naphthoquinones and Breast-Neoplasms

Breast cancer causes the most cancer fatalities in women worldwide. Approximately one-third of breast cancers metastasize, or spread from primary tumors to other tissues, and have a 70% 5-year mortality rate. Current breast cancer treatments like doxorubicin and paclitaxel become ineffective when breast cancer cells develop multi-drug resistance and overexpress ATP-binding cassette transporters, as the transporters cause a substantial efflux of the chemotherapies. Jadomycins, a group of molecules isolated from Streptomyces venezuelae ISP5230, are shown to be cytotoxic against a variety of cancers, especially breast cancer. Furthermore, jadomycins retain their cytotoxic properties in multi-drug resistant breast cancer cells, as they are not expelled through ATP-binding cassette transporters. Here, we describe the research that supports the potential use of jadomycins as a novel chemotherapy in the treatment of multi-drug resistant, metastatic breast cancer. We present the supportive findings, as well as the mechanisms of action investigated thus far. These include copper-mediated reactive oxygen species generation, aurora B kinase inhibition, and topoisomerase IIα and IIβ inhibition. We also suggest future directions of jadomycin research, which will help to determine if jadomycins can be used as a breast cancer chemotherapy in clinical practice.

Topics: Animals; Antineoplastic Agents; Breast Neoplasms; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Female; Humans; Isoquinolines; Naphthoquinones; Streptomyces

The objective of this study was to assess the efficacy and tolerability of YM155, a survivin suppressor, in combination with docetaxel, compared with docetaxel alone in patients with HER2-negative metastatic breast cancer. This phase II, multicenter, open-label, 2-arm study randomized patients (≥18 years) with histologically or cytologically confirmed stage IV HER2-negative metastatic breast cancer and ≥1 measurable lesion, to receive docetaxel alone or docetaxel plus YM155. The primary endpoint was progression-free survival (PFS). Secondary endpoints included objective response rate (ORR), overall survival (OS), duration of response (DOR), clinical benefit rate (CBR), time to response (TTR), biomarker assessment, and analysis of circulating tumor cells. Patients were women diagnosed with HER2-negative breast cancer; most had received prior drug therapies. The median PFS was 8.4 months with YM155 plus docetaxel (n = 50) and 10.5 months with docetaxel alone (n = 51; HR 1.53; 95 % CI 0.83, 2.83; P = 0.176). No statistically significant differences were observed for secondary endpoints, although slightly greater OS (630 vs 601 days; P = 0.768), CBR (84.3 vs 82.0 %; P = 0.855), DOR, and TTR were observed with docetaxel alone compared with YM155 plus docetaxel, whereas ORR was similar (25.5 vs 26.0). The most common TEAEs observed with YM155 plus docetaxel compared with docetaxel alone were neutropenia (83.3 vs 84.3 %), alopecia (62.5 vs 52.9 %), fatigue (50 vs 41.2 %), and nausea (37.5 vs 41.2 %). Although YM155 is a novel drug that suppresses survivin, YM155 plus docetaxel exhibited no statistically significant differences in endpoints compared with docetaxel alone. The combination regimen was well tolerated.

Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Breast Neoplasms; Disease-Free Survival; Docetaxel; Drug-Related Side Effects and Adverse Reactions; Female; Humans; Imidazoles; Lymphatic Metastasis; Middle Aged; Naphthoquinones; Receptor, ErbB-2; Taxoids; Treatment Outcome

Cisplatin (CDDP) is a first-line chemotherapeutic drug for treating various cancers. However, CDDP also damages normal cells and causes many side effects. Recently, CDDP has been demonstrated to kill cancer cells by targeting mitochondria. Protecting mitochondria might be a potential therapeutic strategy for CDDP-induced side effects. β-Lapachone (β-lap), a recognized NAD. In this study, the protective effects of β-lap on mitochondria against CDDP cytotoxicity in normal cells were evaluated.. In vitro cell models were used in this study, including 3T3 fibroblasts, human dermal fibroblasts, MCF-7 breast cancer cells, and MDA-MB-231 breast cancer cells.. Cells were treated with CDDP and β-lap, and cell survival, NAD. β-lap could be a good synergistic drug for reducing the side effects of CDDP without affecting the anticancer drug effect.

Topics: Antineoplastic Agents; Breast Neoplasms; Cell Line, Tumor; Cisplatin; Female; Humans; Mitochondria; NAD; NAD(P)H Dehydrogenase (Quinone); Naphthoquinones

Shikonin is a natural multipotent anti-tumorigenic compound. We investigated potential synergy between shikonin and anti-diabetic metformin against tumorigenic properties of breast cancer cell line MCF-7.. Shikonin and metformin synergize in inhibiting the tumorigenic activities of MCF-7 cells including their proliferation, invasiveness, and EMT with a potential to inhibit multidrug resistance.

Topics: Apoptosis; Breast Neoplasms; Cell Line, Tumor; Cell Movement; Cell Proliferation; Epithelial-Mesenchymal Transition; Female; Humans; MCF-7 Cells; Metformin; Naphthoquinones

Topics: Breast Neoplasms; Cell Hypoxia; Cell Line, Tumor; Female; Humans; Hypoxia; Hypoxia-Inducible Factor 1, alpha Subunit; Naphthoquinones; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; TOR Serine-Threonine Kinases; Vascular Endothelial Growth Factor A

Target treatment using site-specific nanosystems is a hot topic for treating several diseases, especially cancer.. The study was set out to develop site-specific liposomes using ConcanavalinA (ConA) to target β- lapachone(β-lap) to human breast cancer cells.. Liposomes were prepared and characterized according to diameter size, zeta potential, ConA conjugation(%) and β-lap encapsulation efficiency (%). Isothermal Titration Calorimetry evaluated the binding energy between the biomolecules, which compose of the liposomes. ConA avidity was assessed before and after conjugation. Cytotoxicity was evaluated, and fluorescence microscopy was performed to investigate the influence of ConA influenced on MCF-7 uptake.. Uncoated and ConA-coated liposomes presented size, and zeta potential values from 97.46 ± 2.01 to 152.23 ± 2.73 nm, and -6.83 ± 0.28 to -17.23 ±0.64 mV, respectively. Both ConA conjugation and β-lap encapsulation efficiency were approximately 100%. The favorable and spontaneous process confirmed the binding between ConA and the lipid. Hemagglutination assay confirmed ConA avidity once Lipo-ConA and Lipo-PEG-ConA were able to hemagglutinate the red blood cells at 128-1 and 256-1, respectively. Lipo-ConA was not cytotoxic, and the site-specific liposomes presented the highest toxicity. ConA-coated liposomes were more internalized by MCF7 than uncoated-liposomes.. Therefore, the presence of ConA on the surface of liposomes influenced MCF7 uptake, in that way could be used as a promising site-specific system to target β-lap to cancer cells.

Topics: Breast Neoplasms; Concanavalin A; Female; Humans; Liposomes; Naphthoquinones

Rhinacanthin-C is a natural bioactive naphthoquinone ester with potential chemotherapeutic value in cancer treatment. In this study, we investigated its apoptotic induction ability and the involved mechanisms through the mitogen-activated protein kinases (MAPK) and protein kinase B/glycogen synthase kinase-3β/nuclear factor erythroid 2-related factor 2 (Akt/GSK-3β/Nrf2) signaling pathways in doxorubicin-resistant breast cancer MCF-7 (MCF-7/DOX) cells. Our 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that rhinacanthin-C (3-28 µM) significantly decreased the viability of MCF-7/DOX cells and potentiated hydrogen peroxide cytotoxicity. This naphthoquinone was able to increase intracellular reactive oxygen species (ROS), as measured by the 2',7'-dichlorofluorescein diacetate (DCFH-DA) assay. This compound increased the number of apoptotic cells by elevating the ratio of apoptotic checkpoint proteins Bax/Bcl-2 and by decreasing the expression of poly(ADP-ribose) polymerase (PARP) protein. Furthermore, Western blotting analyses showed that treatment with rhinacanthin-C (3-28 µM) for 24 h significantly decreased the expression levels of the phosphorylated forms of MAPK proteins (i.e., extracellular signal regulated protein kinase 1/2 (ERK1/2), c-Jun N-terminal kinases (JNK) and p38), Akt, GSK-3β and Nrf2 proteins in MCF-7/DOX cells. Inhibition of the Akt/GSK-3β/Nrf2 pathway led to a significant reduction in heme oxygenase-1 (HO-1) and reduced nicotinamide adenine dinucleotide phosphate (NADP)(H): quinone oxidoreductase 1 (NQO1) proteins. These findings suggested that rhinacanthin-C was able to induce apoptosis in MCF-7/DOX cells through increased ROS production and suppression of the cell survival systems mediated by the MAPKs and Akt/GSK-3β/Nrf2 signaling pathways.

Topics: Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Breast Neoplasms; Cell Survival; Doxorubicin; Drug Resistance, Neoplasm; Drug Screening Assays, Antitumor; Female; Humans; MAP Kinase Signaling System; MCF-7 Cells; Naphthoquinones; Oxidative Stress; Reactive Oxygen Species

Cancer-associated thrombosis is the second-leading cause of mortality in patients with cancer and presents a poor prognosis, with a lack of effective treatment strategies. NAD(P)H quinone oxidoreductase 1 (NQO1) increases the cellular nicotinamide adenine dinucleotide (NAD

Topics: Animals; Breast Neoplasms; Cell Line, Tumor; Disease Models, Animal; Extracellular Traps; Female; Mice; Mice, Inbred BALB C; NAD; NAD(P)H Dehydrogenase (Quinone); Naphthoquinones; Sirtuin 1; Thrombophilia; Thromboplastin; Thrombosis

Lapachol (LAP) is a natural compound with various biological properties, including anticancer activity. However, its clinical application is limited due to the low aqueous solubility and potential adverse side effects. Nanoemulsions are drug delivery systems that can assist in the administration of hydrophobic drugs, increasing their bioavailability and protecting from degradation. Thus, this study aimed to prepare a LAP-loaded nanoemulsion (NE-LAP), and evaluate its antitumor activity. For this purpose, the nanoemulsion was prepared using a hot homogenization method and characterized morphologically by cryogenic transmission electron microscopy (cryo-TEM). Mean diameter, polydispersity index, and zeta potential was evaluated by DLS, encapsulation efficiency was measured by HPLC. Moreover, the short-term storage stability, the drug release and hemolysis in vitro was determined. Additionally, pharmacokinetic, toxicology and toxicity properties of

Topics: Animals; Antineoplastic Agents, Phytogenic; Breast Neoplasms; Cell Line, Tumor; Drug Compounding; Drug Liberation; Drug Stability; Emulsions; Female; Humans; Mice, Inbred BALB C; Nanoparticles; Naphthoquinones; Tumor Burden

Bioenergetic perturbations driving neoplastic growth increase the production of reactive oxygen species (ROS), requiring a compensatory increase in ROS scavengers to limit oxidative stress. Intervention strategies that simultaneously induce energetic and oxidative stress therefore have therapeutic potential. Phenformin is a mitochondrial complex I inhibitor that induces bioenergetic stress. We now demonstrate that inflammatory mediators, including IFNγ and polyIC, potentiate the cytotoxicity of phenformin by inducing a parallel increase in oxidative stress through STAT1-dependent mechanisms. Indeed, STAT1 signaling downregulates NQO1, a key ROS scavenger, in many breast cancer models. Moreover, genetic ablation or pharmacological inhibition of NQO1 using β-lapachone (an NQO1 bioactivatable drug) increases oxidative stress to selectively sensitize breast cancer models, including patient derived xenografts of HER2+ and triple negative disease, to the tumoricidal effects of phenformin. We provide evidence that therapies targeting ROS scavengers increase the anti-neoplastic efficacy of mitochondrial complex I inhibitors in breast cancer.

Topics: Animals; Antineoplastic Agents; Breast Neoplasms; Cell Line, Tumor; Drug Synergism; Electron Transport Complex I; Energy Metabolism; Female; Glutathione; Humans; Interferon-gamma; Mammary Neoplasms, Experimental; MCF-7 Cells; Mice; Mice, Inbred BALB C; Mice, Knockout; Mice, SCID; NAD(P)H Dehydrogenase (Quinone); Naphthoquinones; Oxidative Stress; Phenformin; Poly I-C; Reactive Oxygen Species; STAT1 Transcription Factor; Xenograft Model Antitumor Assays

Small molecule inhibitors (TKIs) of HER2 have demonstrated clinical benefit in HER2-positive breast tumors. One of them, lapatinib, is used once advanced tumors become refractory to the HER2 antibody trastuzumab. Another one, neratinib, has shown benefit in high-risk early-stage breast cancer after trastuzumab-based therapies. A common characteristic is that patients are formerly treated with trastuzumab. We have explored whether trastuzumab previous therapy affects its antitumoral action. Long time exposure of the HER2+ cell line BT474 to trastuzumab resulted in trastuzumab-insensitive cells (BTRH cells). While treatment of wild type BT474 cells with lapatinib or neratinib resulted in decreased viability, BTRH cells were resistant to the action of these TKIs. Analogous results were obtained using trastuzumab-resistant cells derived from a PDX. Functional transcriptomic analyses and biochemical studies demonstrated that the TKIs caused DNA damage and apoptosis in wild type cells, but not in BTRH. Moreover, previous treatment with trastuzumab impairs response to small TKIs, by eliminating their proapoptotic action. Moreover, actioning on the apoptotic machinery using a chemical library of proapoptotic compounds led to the identification of clinical-stage drugs that may be used to fight trastuzumab-TKI resistance.

Topics: Animals; Antineoplastic Agents, Immunological; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Breast Neoplasms; Cell Line, Tumor; DNA Damage; Drug Resistance, Neoplasm; Female; Gene Expression Profiling; Humans; Imidazoles; Lapatinib; Mice; Naphthoquinones; Protein Kinase Inhibitors; Pyridines; Quinolines; Receptor, ErbB-2; Trastuzumab; Xenograft Model Antitumor Assays

PLB is a natural naphthoquinone compound isolated from the roots of Plumbago indica plant. Our previous study reported the inhibitory effect of Plumbagin (PLB) on human endocrine resistant breast cancer cell growth and cell invasion.. Since PLB is a naphthoquinone compound, it can be reduced by the cytosolic NADPH: quinone oxidoreductase 1 (NQO1) enzyme. NQO1 expression is upregulated in various types of aggressive cancer including breast cancer. This study investigated the impact of NQO1 on anti-cancer effects of PLB in endocrine-resistant breast cancer cells.. This study was an in vitro study using ER-positive cell line (MCF7) and endocrine-resistant cell lines (MCF7/LCC2 and MCF7/LCC9 cells).. The roles of NQO1 in anti-cancer activity of PLB were investigated by using NQO1 knockdown cells, NQO1 inhibitor and NQO1 overexpressed cells. To study the impact of NQO1 on the effects of PLB on cell viability, apoptosis, invasion and generation of ROS, the following assays were used: MTT assays, annexin V-PE/7-ADD staining flow cytometry, matrigel invasion assays and DCFHDA assays. To study the mechanism of how NQO1 mediated PLB effects in tamoxifen response and apoptosis, we assessed the levels of mRNA expression by using qRT-PCR.. 1. In this study, NQO1 was upregulated in endocrine-resistant cells. 2. PLB did not change the expression of NQO1 but it was able to increase NQO1 activity. 3. The inhibitory effects of PLB on cell proliferation, cell invasion and expression of tamoxifen resistant gene were attenuated in NQO1 knockdown cells or in the presence of NQO1 inhibitor. 4. The effects of PLB to induce apoptosis and generate ROS were also decreased when NQO1 activity was inhibited or when the NQO1 expression was reduced. 5. The anti-cancer effects of PLB increased when NQO1 was upregulated.. The effects of PLB in endocrine-resistant breast cancer cells is dependent on NQO1's activity.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Breast Neoplasms; Cell Proliferation; Cell Survival; Drug Resistance, Neoplasm; Female; Humans; MCF-7 Cells; NAD(P)H Dehydrogenase (Quinone); Naphthoquinones; Neoplasm Invasiveness; Tamoxifen

Breast cancer is the most incident and mortal cancer type in women, with an estimated 2 million new cases expected by 2020 worldwide, with 600,000 deaths. As not all breast cancer types respond to the anti-hormonal therapy, the development of new antineoplastic drugs is necessary. Lawsone (2-hydroxy-1,4-naphtoquinone) is a natural bioactive naphtoquinone displaying a range of activities, with dozens of derivatives described in the literature, including some glycosides possessing antitumor activity. Here, a series of glycosides of lawsone are reported for the first time and all compounds displayed good activity against the SKBR-3 cell line, with IC

Topics: Breast Neoplasms; Female; Glycosides; Humans; Molecular Structure; Naphthoquinones; Structure-Activity Relationship

Topics: Antineoplastic Agents, Hormonal; Antineoplastic Agents, Phytogenic; Breast Neoplasms; Drug Resistance, Neoplasm; Female; Humans; MCF-7 Cells; Naphthoquinones; Nuclear Receptor Coactivator 3; Proto-Oncogene Proteins c-akt; Receptor, ErbB-2; Receptors, Estrogen; Signal Transduction

We previously reported the potential of aminonaphthoquinone derivatives as therapeutic agents against breast and other oestrogen-responsive tumours when combined with curcumin. This study aimed at screening of novel aminonaphthoquinone derivatives (Rau 008, Rau 010, Rau 015 and Rau 018) combined with curcumin for cytotoxic, anti-angiogenic and anti-metastatic effects on MCF-7 and MDA-MB-231 breast cancer cells.. Cytotoxic and anti-angiogenic effects were analysed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and enzyme-linked immunosorbent assay; while anti-metastatic effects were measured using adhesion assay, Boyden chambers and Matrigel.. Curcumin combined with Rau 008 elicited marked cytotoxic effects in MCF-7 cells compared with the individual treatments, whereas when it was combined with Rau 015 and with Rau 018, it displayed similar effects in MDA-MB-231 cells. The anti-angiogenic effect of Rau 015 plus curcumin in MCF-7 cells and Rau 018 plus curcumin in MDA-MB-231 cells was more effective than individual treatments, while the metastatic capability of MDA-MB-231 cells was significantly reduced after treatment with the aminonaphthoquinone-curcumin combinations.. Aminonaphthoquinones may offer significant promise as therapeutic agents against breast cancer, particularly when combined with curcumin.

Topics: Breast Neoplasms; Cell Adhesion; Cell Movement; Cell Survival; Curcumin; Disease Progression; Extracellular Matrix; Female; Humans; MCF-7 Cells; Naphthoquinones; Neoplasm Invasiveness; Neovascularization, Pathologic; Vascular Endothelial Growth Factor A

Melanoma is the most dangerous form of skin cancer with a very poor prognosis. Melanoma develops when unrepaired DNA damage causes to skin cells to multiply and form malignant tumors. The current therapy is limited by the highly ability of this disease to metastasize rapidly. Plumbagin is a naphthoquinone (5-hydroxy-2-methyl-1, 4-naphthoquinone), isolated from the roots of medicinal plant Plumbago zeylanica, and it is widely present in Lawsonia inermis L. It has been shown that plumbagin has an anti-proliferative and anti-invasive activities in various cancer cell lines; however, the anti-cancer and anti-metastatic effects of plumbagin are largely unknown against melanoma cells. In this study, we evaluated the effect of plumbagin on B16F10 murine melanoma cells . Plumbagin decreased B16F10 cell viability as well as the cell migration, adhesion, and invasion. The molecular mechanism was studied, and plumbagin downregulated genes relevant in MAPK pathway, matrix metalloproteinases (MMP's), and cell adhesion. Furthermore, plumbagin elevated the expression of apoptosis and tumors suppressor genes, and genes significant in reactive oxygen species (ROS) response. Taken together, our findings suggest that plumbagin has an anti-invasion and anti-metastasis effect on melanoma cancer cells by acting on MAPK pathway and its related genes.

Topics: Animals; Breast Neoplasms; Cell Adhesion; Cell Line, Tumor; Cell Proliferation; Cell Survival; Female; Gene Expression Regulation, Neoplastic; Humans; MAP Kinase Signaling System; Melanoma; Melanoma, Experimental; Mice; Naphthoquinones; Neoplasm Invasiveness; Neoplasm Metastasis; Oligonucleotide Array Sequence Analysis; Plant Extracts; Signal Transduction; Wound Healing

Despite recent progress in molecular-targeted therapies, breast cancer remains the primary leading cause of cancer related death among women worldwide. Breast cancer stem cells (BCSCs) are believed to be responsible for therapy resistance and cancer recurrence. We recently demonstrated that human BCSCs (CD24-/CD44+) could survive better than their counterpart non-BCSCs (CD24-/CD44-) when treated with rotenone, possibly due to lower levels of reactive oxygen species (ROS) production, high expression of antioxidant manganese superoxide dismutase (MnSOD), and anti-apoptotic survivin. The aim of this study was to verify the role of survivin on human BCSCs survival under oxidative stress modulation by suppressing its expression using YM155, a survivin inhibitor.. Human BCSCs (ALDH+ cells) were treated with YM155 for 24 h prior to treatment with rotenone for a further 6 h. We determined intracellular superoxide levels were determined using dihydroethidium assay, survivin and MnSOD expression using qRT-PCR, survivin protein level using ELISA, as well as cell viability using trypan blue exclusion and acridine orange/ethidium bromide apoptosis assay.. Suppression of survivin expression using YM155 could reduce the survival of rotenone-treated BCSCs, which may be associated with oxidative stress modulation, as shown by increased ROS levels and decreased MnSOD expression. We confirm that survivin is responsible for maintaining BCSCs survival under oxidative stress modulation. Furthermore, YM155 could modulate oxidative stress in BCSCs by reducing MnSOD expression and increasing ROS levels.. YM155 treatment could be used to overcome BCSCs resistance to oxidative stress-based anticancer therapies.

Topics: Antineoplastic Agents; Apoptosis; Breast Neoplasms; Cell Proliferation; Female; Gene Expression Regulation, Neoplastic; Humans; Imidazoles; Insecticides; Naphthoquinones; Neoplastic Stem Cells; Oxidative Stress; Rotenone; Survivin; Tumor Cells, Cultured

The reaction of 2-acyl-1,4-naphthoquinones with

Topics: Antineoplastic Agents; Antioxidants; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Drug Screening Assays, Antitumor; Electrochemical Techniques; Female; HEK293 Cells; Humans; Male; Naphthoquinones; Oxidation-Reduction; Prostatic Neoplasms; Structure-Activity Relationship

To study anticancer effects, underlying mechanism and safety of ethoxy mansonone G (EMG) which is the potent derivative of mansonone G (MG) in breast cancer cells.. Anticancer, antimigration, anti-invasion effects and anchorage-independent growth were investigated by MTT, scratch, matrigel invasion and soft agar assays. Estrogen receptor (ER)-targeted genes and endocrine-resistant genes were assessed by RT-PCR and Western blot.. Ethoxy mansonone G is the most potent MG derivative and has anticancer effects in ER-positive, endocrine-resistant and ER-negative breast cancer cells. Our results demonstrated that EMG can significantly inhibit estrogen-induced cell proliferation and the expression of ER-targeted genes in ER-positive breast cancer cells, suggesting the anti-estrogenic property of EMG which is consisting with the virtual molecular docking that EMG could possibly bind to the ERα. Moreover, EMG has synergistic effect with tamoxifen in endocrine-resistant cells. EMG also inhibited cell proliferation, invasion and anchorage-independent growth by reducing expression of genes involved in endocrine resistance and invasive factors during the metastatic process.. Ethoxy mansonone G has an anticancer effect in breast cancer cells and is possible to use as a therapeutic agent in patients with breast cancer.

Topics: Antineoplastic Agents, Hormonal; Breast Neoplasms; Cell Proliferation; Drug Resistance, Neoplasm; Drug Synergism; Estrogen Receptor alpha; Ethyl Ethers; Female; Gene Expression Regulation, Neoplastic; Humans; MCF-7 Cells; Molecular Docking Simulation; Naphthoquinones; Receptors, Estrogen; Tamoxifen

Breast cancer is the second in mortality rate malignancy among women. Despite the many advances in breast cancer treatment, there is still a need to improve drug efficacy and reduce non-specific effects. D-alpha-tocopheryl polyethylene glycol succinate (TPGS) is frequently used in the development of drug delivery systems to improve the pharmacokinetics of anti-cancer drugs and reduce multi-drug resistance. We have previously shown that TPGS not only acts as a carrier molecule but also exerts anti-cancer effects. As part of this study, we investigated the effect of TPGS with YM155, a small molecule suppressant of Survivin, in various breast cancer cell lines representing different subtypes of the disease. We aimed to evaluate the presumed synergistic effect of the TPGS-YM155 combination and reveal its mechanism of action. Our results show that the TPGS-YM155 combination acts synergistically to reduce specifically the viability of SKBR3 cells. The combination of these agents reduced activation of the AKT pathway, decreased Survivin and Bcl-2 levels, and induced caspase-dependent and independent apoptosis via the mitochondrial pathway. Importantly, the TPGS-YM155 combination did not significantly affect the viability of MCF-10A normal immortalized cells. In conclusion, the combination of YM155 and TPGS could be a promising approach against SKBR3-type breast cancer.

Topics: Apoptosis; Breast Neoplasms; Drug Delivery Systems; Drug Synergism; Female; Gene Expression Regulation, Neoplastic; Humans; Imidazoles; MCF-7 Cells; Naphthoquinones; Survivin; Vitamin E

BACKGROUND Tamoxifen (TAM) is the first-line drug for estrogen receptor-positive (ER+) breast cancer (BC) treatment. However, its resistance is a main obstacle in clinical practice. Thus, new therapeutic agents are urgently needed to fight TAM resistance. MATERIAL AND METHODS Here, we constructed TAM-resistant ER+BC cells with TAM resistance, named MCF-7-R. Western blot, quantitative real-time PCR (qRT-PCR), ALDH1 activity analysis, and spheroid-forming detection were used to detect the stemness of cells and the effects of napabucasin (NP) on BC cell stemness. Cell counting kit-8 (CCK8) assay was used to evaluate the effects of NP on cell viability. RESULTS MCF-7-R cells exhibited higher stemness compared with the parental MCF-7 cells, which was evident by the increased spheroid formation ability at diluted concentration, aldehyde dehydrogenase (ALDH) activity, and expression of stemness critical biomarkers (Oct4, Nanog, and Sox2). Additionally, it was found that napabucasin (NP) specifically killed MCF-7-T cells, characterized by remarkably decreased IC₅₀ value. Notably, NP reduced MCF-7-R cell stemness, which was evident as the decreased stemness marker expression, spheroid-forming capacity, and ALDH1 activity. Importantly, NP attenuated TAM resistance of MCF-7-R cells and enhanced sensitivity of MCF-7 cells to TAM. Mechanistic study showed that NP inhibited STAT3 activation, and overexpression of STAT3 rescued NP-mediated inhibition of the stemness-like characteristics of MCF-7-R cells. CONCLUSIONS NP might be used as an adjuvant therapy for ER+ BC patients with TAM resistance.

Topics: Antineoplastic Agents, Hormonal; Apoptosis; Benzofurans; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Cell Survival; China; Drug Resistance, Neoplasm; Estrogen Receptor alpha; Humans; MCF-7 Cells; Naphthoquinones; Neoplastic Stem Cells; Receptors, Estrogen; Signal Transduction; Stem Cells; Tamoxifen

We performed an extensive analysis about the reaction conditions of the 1,4-Michael addition of amino acids to 1,4-naphthoquinone and substitution to 2,3-dichloronaphthoquinone, and a complete evaluation of stoichiometry, use of different bases, and the pH influence was performed. We were able to show that microwave-assisted synthesis is the best method for the synthesis of naphthoquinone-amino acid and chloride-naphthoquinone-amino acid derivatives with 79-91% and 78-91% yields, respectively. The cyclic voltammetry profiles showed that both series of naphthoquinone-amino acid derivatives mainly display one quasi-reversible redox reaction process. Interestingly, it was shown that naphthoquinone derivatives possess a selective antitumorigenic activity against cervix cancer cell lines and chloride-naphthoquinone-amino acid derivatives against breast cancer cell lines. Furthermore, the newly synthetized compounds with asparagine-naphthoquinones (

Topics: Amino Acids; Antineoplastic Agents; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Drug Screening Assays, Antitumor; Female; Humans; Naphthoquinones; Uterine Cervical Neoplasms

Topics: Animals; Antineoplastic Agents, Phytogenic; Apoptosis; Breast Neoplasms; Caryophyllales; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Female; Humans; MCF-7 Cells; Mice, Inbred BALB C; Mice, Nude; Naphthoquinones; Reactive Oxygen Species; Tumor Suppressor Protein p53

One million females are diagnosed worldwide every year with breast cancer, and the mortality rate of these patients remains high. Several treatments, including surgery, are available for breast cancer. β‑Lapachone (β‑Lap), a natural quinone compound, has been developed for cancer treatment due to its strong cytotoxic effect through its action on NAD(P)H:quinone oxidoreductase 1 (NQO1)‑dependent activity. However, the mechanism in regards to how β‑Lap induces cytotoxicity in breast cancer cells is still elusive. In the present study, we showed that β‑Lap induced apoptotic cell death via activation of protein kinase A (PKA) in NQO1‑overexpressing MDA‑MB‑231 human breast cancer cells. This PKA‑dependent cell death was observed solely in NQO1‑overexpressing 231 cells via the high production of reactive oxygen species (ROS). Cell survival of antioxidant [N‑acetylcysteine (NAC)]‑treated NQO1‑overexpressing 231 cells was significantly recovered, and NQO1‑negative 231 cells did not respond to β‑Lap. Antiapoptotic proteins such as Bcl2 and Bcl‑xL were decreased, while proapoptotic proteins, including cytochrome c, activation of caspase‑3, and cleavage of PARP were increased after β‑Lap treatment of NQO1‑overexpressing 231 cells. Furthermore, PKA activators, forskolin or dibutyryl‑cAMP, an analog of cAMP, aggravated the β‑Lap‑induced apoptotic cell death by decreasing antiapoptotic proteins and further activating proapoptotic proteins in NQO1‑positive 231 cells. Treatment with a PKA inhibiter, H89, significantly increased cell viability even in NQO1‑overexpressing cells treated with β‑Lap. These data showed that β‑Lap activated PKA via ROS accumulation, subsequently leading to apoptotic cell death in NQO1‑positive breast cancer cells.

Topics: Apoptosis; Breast Neoplasms; Cell Line, Tumor; Cyclic AMP-Dependent Protein Kinases; Enzyme Activation; Female; Humans; NAD(P)H Dehydrogenase (Quinone); Naphthoquinones; Reactive Oxygen Species

Recognition of a new therapeutic agent may activate an alternative programmed cell death for the treatment of breast cancer.. Here, it has been tried to evaluate the effects of Shikonin, a naphthoquinone derivative of Lithospermum erythrorhizon, on the induction of necroptosis and apoptosis mediated by RIPK1-RIPK3 in the ER+ breast cancer cell line, MCF-7.. In the current study, cell death modalities, cell cycle patterns, RIPK1 and RIPK3 expressions, caspase-3 and caspase-8 activities, reactive oxygen species and mitochondrial membrane potential have been evaluated in the Shikonin-treated MCF-7 cells.. Necroptosis and apoptosis have been occurred by Shikonin, with a significant increase in RIPK1 and RIPK3 expressions, although necroptosis was the major rout in MCF-7 cells. Shikonin significantly increased the percentage of the cells in sub-G1 and also those in the later stages of cell cycle, which represents an increase in necroptosis and apoptosis. Under caspase inhibition by Z-VAD-FMK, Shikonin has stimulated necroptosis, which could be arrested by Nec-1. An increase in ROS levels and a decrease in the mitochondrial membrane potential have also been observed.. On the basis of present findings, Shikonin has been suggested as a good candidate for the induction of cell death in ER+ breast cancer, although further investigations, experimental and clinical, are required.

Topics: Antineoplastic Agents; Breast Neoplasms; Cell Cycle; Cell Death; Cell Proliferation; Cell Survival; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Female; Humans; MCF-7 Cells; Membrane Potential, Mitochondrial; Molecular Structure; Naphthoquinones; Reactive Oxygen Species; Receptors, Estrogen; Structure-Activity Relationship; Tumor Cells, Cultured

A new naphthoquinone, teratosphaerone A (1), four new naphthalenones, namely, teratosphaerone B (2), structurally related to 1, iso-balticol B (3), iso-balticol B-4,9-acetonide (4), and (+)-balticol C (5), a new furanonaphthalenone, (3a S,9 R,9a S)-1(9a),3(3a),9-hexahydromonosporascone (6), and the known metabolite monosporascone (7) were isolated from Teratosphaeria sp. FL2137, a fungal strain inhabiting the internal tissue of recently dead but undecomposed foliage of Pinus clausa. The structures of 1-6 were elucidated on the basis of their spectroscopic data including 2D NMR, and absolute configurations of 2, 3, and 6 were determined by the modified Mosher's ester method. When evaluated in a panel of five tumor cell lines, metabolites 1 and 7 isolated from a cytotoxic fraction of the extract exhibited moderate selectivity for metastatic breast adenocarcinoma cell line MDA-MB-231. Of these, 1 showed cytotoxicity to this cell line with an IC

Topics: Ascomycota; Breast Neoplasms; Cell Line, Tumor; Cytotoxins; Drug Screening Assays, Antitumor; Humans; Magnetic Resonance Spectroscopy; Naphthoquinones; Pinus

Shikonin (SHK) has been proven to have a good anti-tumor effect. However, poor water solubility and low bioavailability limit its wide application in clinical practice. In this study, to overcome these drawbacks, RGD-modified shikonin-loaded liposomes (RGD-SSLs-SHK) were successfully prepared. It exhibited excellent physicochemical characteristics including particle size, zeta potential, encapsulation efficiency, and delayed release time. Meanwhile, the targeting activity of the RGD-modified liposomes was demonstrated by flow cytometry and confocal microscopy in the α

Topics: Apoptosis; bcl-2-Associated X Protein; Breast Neoplasms; Cell Adhesion; Cell Movement; Cell Proliferation; Female; Gene Expression Regulation, Neoplastic; Humans; Liposomes; MCF-7 Cells; Naphthoquinones; Oligopeptides; Proto-Oncogene Proteins c-bcl-2; Transcription Factor RelA

Emerging evidence showed that alteronol has a potential antitumour effect in several tumour cells. However, the antitumour effect of alteronol on breast cancer has not been reported. This study investigated the mechanisms of alteronol-induced cell proliferation inhibition in human breast cancer T47D cells.. After treatment with alteronol, T47D cell proliferation was examined by MTT assay. The cell cycle distribution, cell apoptosis, reactive oxygen species level and mitochondrial membrane potential were evaluated via flow cytometry. Next, the protein levels of cyclin B1, cdc2, p21, p-cyclin B1, p-cdc2, p53, Bax, Bcl-2 and cytochrome c were analysed using Western blot analysis. Meanwhile, the mRNA levels of cyclin B1, cdc2, p21 and p53 were examined by qRT-PCR.. Our data showed that alteronol inhibited the proliferation of T47D cells via inducing G2-phase arrest and cell apoptosis. Compared with control group, alteronol significantly increased ROS level and triggered mitochondrial dysfunction in alteronol-treated T47D cells. Further studies showed that the mRNA and protein levels of cdc2 and cyclin B1 were downregulated, while the mRNA and protein levels of p21, p53, p-cyclin B1, p-cdc2 and cytochrome c were upregulated. In addition, the expression level of Bax was increased, and the expression level of Bcl-2 was decreased.. Alteronol induced T47D cell cycle arrest and cell apoptosis through increasing ROS production and triggering mitochondrial dysfunction, and subsequently inhibiting T47D cell proliferation.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Breast Neoplasms; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Proliferation; Dose-Response Relationship, Drug; Female; Humans; Naphthoquinones; Reactive Oxygen Species

Shikonin is a naphthoquinone isolated from the dried root of Lithospermum erythrorhizon, an herb used in Chinese medicine. Although several studies have indicated that shikonin exhibits antitumor activity in breast cancer, the mechanism of action remains unclear. In the present study, we performed transcriptome analysis using RNA-seq and explored the mechanism of action of shikonin in regulating the growth of different types of breast cancer cells. The IC

Topics: Apoptosis; Breast Neoplasms; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Proliferation; Dual Specificity Phosphatase 1; Dual Specificity Phosphatase 2; Gene Expression Profiling; Humans; Lithospermum; MAP Kinase Signaling System; MCF-7 Cells; Naphthoquinones; RNA; Signal Transduction; Transcriptome

Multidrug resistance is responsible for the poor outcome in breast cancer therapy. Lapa is a novel therapeutic agent that generates ROS through the catalysis of the NAD(P) H:quinone oxidoreductase-1 (NQO1) enzyme which significantly facilitate the intracellular accumulation of the co-delivered DOX to overcome MDR in cancer cells.. Herein, in our study, nanostructured lipid carrier (NLC) co-delivering β-lapachone (Lapa) and doxorubicin (DOX) was developed (LDNLC) with the aim to overcome the multidrug resistance (MDR) in breast cancer therapy.. Lapa and DOX were loaded into NLC to prepare LDNLC using melted ultrasonic dispersion method.. The well designed LDNLC was nanoscaled particles that exhibited preferable stability in physiological environment. In vitro cell experiments on MCF-7 ADR cells showed increased DOX retention as compared to DOX mono-delivery NLC (DNLC). In vivo anti-cancer assays on MCF-7 ADR tumor bearing mice model also revealed significantly enhanced efficacy of LDNLC than mono-delivery NLCs (DNLC and LNLC).. LDNLC might be a promising platform for effective breast cancer therapy.

Topics: Adenosine Triphosphate; Animals; Antineoplastic Agents; Breast Neoplasms; Cell Death; Cell Survival; Colloids; Doxorubicin; Drug Carriers; Drug Liberation; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Female; Hemolysis; Humans; Lipids; MCF-7 Cells; Mice, Inbred BALB C; Mice, Nude; Nanostructures; Naphthoquinones; Particle Size; Rabbits; Static Electricity; Tissue Distribution; Tumor Burden

Cancer stem cells (CSCs) exhibit self-renewal activity and give rise to other cell types in tumors. Due to the infinite proliferative potential of CSCs, drugs targeting these cells are necessary to completely inhibit cancer development. The β-lapachone (bL) compound is widely used to treat cancer development; however, its effect on cancer stem cells remain elusive. Thus, we investigated the effect of bL on mammosphere formation using breast-cancer stem-cell (BCSC) marker-positive cells, MDA-MB-231. MDA-MB-231 cells, which are negative for reduced nicotinamide adenine dinucleotide phosphate (NAD(P)H):quinone oxidoreductase (NQO1) expression, were constructed to stably express NQO1 (NQO1 stable cells). The effect of bL on these cells was evaluated by wound healing and Transwell cell-culture chambers, ALDEFLUOR assay, and mammosphere formation assay. Here, we show that bL inhibited the proliferative ability of mammospheres derived from BCSC marker-positive cells, MDA-MB-231, in an NQO1-dependent manner. The bL treatment efficiently downregulated the expression level of BCSC markers cluster of differentiation 44 (CD44), aldehyde dehydrogenase 1 family member A1 (ALDH1A1), and discs large (DLG)-associated protein 5 (DLGAP5) that was recently identified as a stem-cell proliferation marker in both cultured cells and mammosphered cells. Moreover, bL efficiently downregulated cell proliferation and migration activities. These results strongly suggest that bL could be a therapeutic agent for targeting breast-cancer stem-cells with proper NQO1 expression.

Topics: Blotting, Western; Breast Neoplasms; Cell Line, Tumor; Cell Movement; Humans; Immunohistochemistry; MCF-7 Cells; NAD(P)H Dehydrogenase (Quinone); Naphthoquinones; Neoplastic Stem Cells; Real-Time Polymerase Chain Reaction; Wound Healing

NQO1 is a FAD-binding protein that can form homodimers and reduce quinones to hydroquinones, and a growing body of evidence currently suggests that NQO1 is dramatically elevated in solid cancers. Here, we demonstrated that NQO1 was elevated in breast cancer and that its expression level was positively correlated with invasion and reduced disease free survival (DFS) and overall survival (OS) rates. Next, we found that β-lapachone exerted significant anti-proliferation and anti-metastasis effects in breast cancer cell lines due to its effects on NQO1 expression. Moreover, we revealed that the anti-cancer effects of β-lapachone were mediated by the inactivation of the Akt/mTOR pathway. In conclusion, these results demonstrated that NQO1 could be a useful prognostic biomarker for patients with breast cancer, and its bioactivatable drug, β-lapachone represented a promising new development and an effective strategy for indicating the progression of NQO1-positive breast cancers.

Topics: Animals; Biomarkers, Tumor; Breast Neoplasms; Cell Line, Tumor; Cell Movement; Cell Proliferation; Disease Models, Animal; Disease Progression; Dose-Response Relationship, Drug; Epithelial-Mesenchymal Transition; Female; Gene Expression; Humans; Mice; NAD(P)H Dehydrogenase (Quinone); Naphthoquinones; Neoplasm Grading; Neoplasm Staging; Prognosis; Xenograft Model Antitumor Assays

The Chinese traditional medicine Shikonin is an ideal drug due to its multiple targets to tumor cells. But in clinics, improving its aqueous solubility and tumor accumulation is still a challenge. Herein, a copolymer with tunable poly(N-isopropylacrymaide) and polylactic acid block lengths is designed, synthesized, and characterized in nuclear magnetic resonance. The corresponding thermosensitive nanomicelle (TN) with well-defined core-shell structure is then assembled in an aqueous solution. For promoting the therapeutic index, the physical-chemistry properties of TNs including narrow size, low critical micellar concentration, high serum stability, tunable volume phase transition temperature (VPTT), high drug-loading capacity, and temperature-controlled drug release are systematically investigated and regulated through the fine self-assembly. The shikonin is then entrapped in a degradable inner core resulting in a shikonin-loaded thermosensitive nanomicelle (STN) with a VPTT of ~40°C. Compared with small-molecular shikonin, the in vitro cellular internalization and cytotoxicity of STN against breast cancer cells (Michigan Cancer Foundation-7) are obviously enhanced. In addition, the therapeutic effect is further enhanced by the programmed cell death (PCD) specifically evoked by shikonin. Interestingly, both the proliferation inhibition and PCD are synergistically promoted as T > VPTT, namely the temperature-regulated passive targeting. Consequently, as intravenous injection is administered to the BALB/c nude mice bearing breast cancer, the intratumor accumulation of STNs is significantly increased as T > VPTT, which is regulated by the in-house developed heating device. The in vivo antitumor assays against breast cancer further confirm the synergistically enhanced therapeutic efficiency. The findings of this study indicate that STN is a potential effective nanoformulation in clinical cancer therapy.

Topics: Animals; Antineoplastic Agents; Breast Neoplasms; Delayed-Action Preparations; Drugs, Chinese Herbal; Female; Humans; Hyperthermia, Induced; MCF-7 Cells; Mice, Inbred BALB C; Micelles; Nanostructures; Naphthoquinones; Polyesters; Polymers; Solubility; Temperature; Tissue Distribution; Xenograft Model Antitumor Assays

The early detection and thus treatment of breast cancer bone metastasis remain a big challenge clinically. As the most abundant cells within bone tissue, osteocytes have been found to manipulate the activity of early cancer bone metastasis by its crosstalk with cancer cells and osteoclasts. However, conventional bone-targeting nanomedicine has limited bone-lesion specificity and ignores the vital role of osteocytes during breast cancer bone metastasis. Also, it lacks detailed insight into the therapeutic mechanisms, which hinders the following translational practice. Previously, we have shown that a combination of zoledronic acid (ZA) and plumbagin (PL) synergistically alleviates cancer-induced bone destruction. Herein, we further develop a pH-responsive bone-targeting drug delivery system, i.e., the ZA-anchored bimodal mesoporous slica covered gadolinium(III) upconversion nanoparticles loaded with PL, to detect and treat bone metastasis sensitively and specifically at an early stage. This multifunctional nanosystem can target osteocytes to release PL as controlled by pH, decreasing osteocytic RANKL expression synergistically through the structural simulation of adenosine phosphate, which competitively inhibits the phosphorylation of osteocytic protein kinase-a, cAMP-response element binding protein, extracellular regulated protein kinase, and c-Jun N-terminal kinase. More importantly, by establishing a breast cancer bone metastasis mice model via intracardiac injection, we show that tumoriogenesis and osteoclastogenesis can both be attenuated significantly. We thereby realize the effective theranostics of tiny bone metastasis in breast cancer bone metastasis. Our work highlights the significance of theranostic nanomedicine and osteocyte-targeting therapy in the treatment of early bone metastasis, which could be applied in achieving efficient theranostic effects for other bone diseases.

Topics: Animals; Antineoplastic Agents, Phytogenic; Bone Density Conservation Agents; Bone Neoplasms; Breast Neoplasms; Cell Line, Tumor; Delayed-Action Preparations; Drug Delivery Systems; Female; Gadolinium; Humans; Luminescent Agents; Mice; Mice, Nude; Nanoparticles; Naphthoquinones; Optical Imaging; Osteocytes; Silicon Dioxide; Theranostic Nanomedicine; Zoledronic Acid

The signal transducer and activator of transcription 3 is a constitutively activated oncogenic protein in various human tumors and represents a valid target for anticancer drug design. In this study, we have achieved a new type of STAT3 inhibitors based on structural modifications on shikonin scaffold, guided by computational modelling. By tests, PMMB-187 exhibited a more outstanding profile than shikonin on a small panel of human breast cancer cells, especially for the MDA-MB-231 cells. For the cellular mechanisms research, PMMB-187 was found to induce cell apoptosis in MDA-MB-231 cells, associated with the reduction of mitochondrial membrane potential, production of ROS and alteration of the levels of apoptosis-related proteins. Furthermore, PMMB-187 inhibited constitutive/inducible STAT3 activation, transcriptional activity, nuclear translocation and downstream target genes expression in STAT3-dependent breast cancer cells MDA-MB-231. Besides, no obvious inhibitory effect on activation of STAT1 and STAT5 was observed with PMMB-187 treatment. Most notably, the in vivo studies further revealed that PMMB-187 could dramatically suppress the MDA-MB-231 cells xenografted tumor growth. The in vitro and in vivo results collectively suggest that PMMB-187 may serve as a promising lead compound for the further development of potential therapeutic anti-neoplastic agents.

Topics: Antineoplastic Agents; Apoptosis; Breast Neoplasms; Cell Line, Tumor; Female; Humans; Membrane Potential, Mitochondrial; Models, Molecular; Molecular Structure; Naphthoquinones; STAT3 Transcription Factor; Thiadiazoles

Combination therapies are often explored to treat cancer. The use of curcumin as an adjuvant to current chemotherapies has been reported, whilst aminonaphthoquinones have shown potential as anticancer agents in various tumour cell lines. This study aimed at screening synthetic aminonathoquinone derivatives (Rau 008, Rau 010, Rau 015 and Rau 018) alone and in combination with curcumin for anti-breast cancer activity.. Combination effects were determined in MCF-7 breast cancer cells using combination index analyses. Synergistic anti-proliferative effects were further investigated in breast (MCF-7, MDA-MB-231), osteosarcoma (MG-63) and endometrial (HEC-1A) cancer-derived cells.. Rau 015 (15 μM) and curcumin (112.5 μM) significantly reduced MCF-7, MDA-MB-231 and MG-63 cell proliferation compared to individual treatment, indicating synergistic anti-proliferative effects. Rau 018 (30 μM) and curcumin (100 μM) displayed similar effects in MCF-7 and MG-63 cells.. We report on the potential of Rau 015 or Rau 018 as anti-breast cancer agents when combined with curcumin.

Topics: Alkaline Phosphatase; Antineoplastic Agents; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Curcumin; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Drug Synergism; Female; Humans; Insulin-Like Growth Factor Binding Protein 3; MCF-7 Cells; Molecular Structure; Naphthoquinones; Receptors, Estrogen

β-Lapachone is a drug candidate in phase II clinical trials for treatment of solid tumors. The therapeutic efficacy of β-lapachone is closely related to its metabolism, since this o-naphthoquinone produces cytotoxic effect after intracellular bioreduction by reactive oxygen species formation. The aim of this study was to produce β-lapachone human blood phase I metabolites to evaluate their cytotoxic activities.. The biotransformation of β-lapachone was performed using Mucor rouxii NRRL 1894 and Papulaspora immersa SS13. The metabolites were isolated and their chemical structures determined from spectrometric and spectroscopic data. Cell cytotoxicity assays were carried out with β-lapachone and its metabolites using the neoplastic cell line SKBR-3 derived from human breast cancer and normal human fibroblast cell line GM07492-A.. Microbial transformation of β-lapachone by filamentous fungi resulted in the production of five metabolites identical to those found during human blood metabolism, a novel metabolite and a product stated before only in a synthetic procedure. The analysis of the results showed that β-lapachone metabolites were not cytotoxic for the neoplastic cell line SKBR-3 derived from human breast cancer and the normal human fibroblast cell line GM07492-A. The cytotoxic activity assay against the neoplastic cell line SKBR-3 revealed that the lowest half-maximal inhibitory concentration (IC. The cytotoxic activity of β-lapachone in vivo may be reduced due to its swift conversion in blood.

Topics: Antineoplastic Agents; Breast Neoplasms; Cell Line; Cell Line, Tumor; Female; Fibroblasts; Fungi; Humans; Inhibitory Concentration 50; Mucor; Naphthoquinones

Trastuzumab (Herceptin) monoclonal antibody directed against HER2 receptor has been administered as a treatment for metastatic HER2 positive breast cancer. The problematic issue in treatment of HER2 positive breast cancer cells is commonly the induction of resistance to trastuzumab which might be due to modulation of some vital signaling elements such as Notch1 and Pin1. In this study, we were aimed to investigate whether the cross talk between pin1 and Notch1 has a role in this event. Our results indicated that the expression level of Pin1 in resistant SKBR3 cells increased by about twofold relative to sensitive SKBR3 cells. Besides, Pin1 inhibition via juglone reduced the extent of proliferation, colony formation and migration capacity of resistant SKBR3 cells. In addition, despite a feed forward loop between Notch1 and Pin1 in sensitive SKBR3 cells, inhibition of Notch1 cleavage in resistant SKBR3 cells did not affect pin1 level whereas pin1 inhibition by juglone reduced the level of Hes1, p-Akt and increased the cellular content of Numb. Therefore, we concluded that pin1 inhibition could be considered as a promising sensitizing strategy to weaken trastuzumab resistance.

Topics: Breast Neoplasms; Drug Resistance, Neoplasm; Female; Gene Expression Regulation, Neoplastic; Humans; Membrane Proteins; Naphthoquinones; Nerve Tissue Proteins; NIMA-Interacting Peptidylprolyl Isomerase; Proto-Oncogene Proteins c-akt; Receptor, ErbB-2; Receptor, Notch1; Signal Transduction; Transcription Factor HES-1; Trastuzumab

Rhinacanthin-C is a major bioactive naphthoquinone ester found in Rhinacanthus nasutus Kurz (Acanthaceae). This compound has potential therapeutic value as an anticancer and antiviral agent. In this study, we investigated an enhancement effect of rhinacanthin-C on doxorubicin cytotoxicity in human breast cancer cell lines and the involvement of the ABC drug efflux transporters. The cytotoxicity was determined by an MTT assay. Combination between doxorubicin and rhinacanthin-C at their non-cytotoxic concentrations when giving each compound alone significantly reduced cell viability in MCF-7 and MCF-7/DOX resistant cells. At the non-cytotoxic concentration (0.1µM), rhinacanthin-C enhanced doxorubicin cytotoxicity by 38 fold in MCF-7 cells after 48-h treatment. Moreover, intracellular doxorubicin accumulation significantly increased in both MCF-7 cells and MCF-7/DOX resistance cells in the presence of rhinacanthin-C for 6-h treatment period. The interference of rhinacanthin-C on the ABC drug transporters (P-gp, MRP1 and MRP2) was evaluated by substrate accumulation assay, using fluorescence spectroscopy technique. Our results showed that rhinacanthin-C at 0.1µM for 6-h treatment period could increase intracellular accumulation of transporter substrates in MCF-7 cells [i.e., CDCF by 1.65 fold (MRP2)] as well as in MCF-7/DOX resistance cells [i.e., CDCF by 1.18 fold (MRP2) and calcein by 1.38 fold (P-gp)]. In conclusion, rhinacanthin-C could enhance doxorubicin cytotoxicity through interference on MRP2 and P-gp functions. Consequently, intracellular doxorubicin accumulation in the cells increased up to its cytotoxic level. Another potential mechanism of the synergy between rhinacanthin-C and doxorubicin would be investigated further.

Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; Breast Neoplasms; Doxorubicin; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Drug Synergism; Humans; Intracellular Space; MCF-7 Cells; Multidrug Resistance-Associated Protein 2; Multidrug Resistance-Associated Proteins; Naphthoquinones

The glucose regulated protein 78 (GRP78) is a major chaperone of the endoplasmic reticulum, and a prosurvival component of the unfolded protein response. GRP78 is upregulated in many types of cancers, including breast cancer. Research has suggested that GRP78 overexpression confers chemoresistance to anti-estrogen agents through a mechanism involving the inhibition of a pro-apoptotic BH3-only protein, Bik. In the present research the role of plumbagin, a naturally occurring naphthoquinone, in GRP78-associated cell death inhibition was examined. The results demonstrated that plumbagin inhibits GRP78 activity and GRP78 inhibition contributes to plumbagin-mediated cell death induction. Furthermore, Bik upregulation was associated with plumbagin-induced cell death and an increase in plumbagin-mediated Bik induction was observed upon GRP78 downregulation. Plumbagin sensitized estrogen-positive breast cancer cells to tamoxifen and the association of GRP78 inhibition and Bik upregulation in plumbagin-mediated cell sensitization was shown. Collectively, the results of this research suggest that plumbagin inhibits the antiapoptotic activity of GRP78 leading to Bik upregulation and apoptosis induction, which contributes to the sensitization of breast cancer cells to tamoxifen.

Topics: Antineoplastic Agents, Hormonal; Antineoplastic Agents, Phytogenic; Apoptosis; Apoptosis Regulatory Proteins; Breast Neoplasms; Cell Line, Tumor; Cell Survival; Endoplasmic Reticulum Chaperone BiP; Female; Heat-Shock Proteins; Humans; MCF-7 Cells; Membrane Proteins; Mitochondrial Proteins; Naphthoquinones; RNA Interference; Tamoxifen

The phosphoinositide 3-kinase (PI3K) signaling pathway plays an important role in processes critical for breast cancer progression and its upregulation confers increased resistance of cancer cells to chemotherapy and radiation. The present study aimed at determining the activity of ramentaceone, a constituent of species in the plant genera Drosera, toward breast cancer cells and defining the involvement of PI3K/Akt inhibition in ramentaceone-mediated cell death induction. The results showed that ramentaceone exhibited high antiproliferative activity toward breast cancer cells, in particular HER2-overexpressing breast cancer cells. The mode of cell death induced by ramentaceone was through apoptosis as determined by cytometric analysis of caspase activity and Annexin V staining. Apoptosis induction was found to be mediated by inhibition of PI3K/Akt signaling and through targeting its downstream anti-apoptotic effectors. Ramentaceone inhibited PI3-kinase activity, reduced the expression of the PI3K protein and inhibited the phosphorylation of the Akt protein in breast cancer cells. The expression of the anti-apoptotic Bcl-2 protein was decreased and the levels of the pro-apoptotic proteins, Bax and Bak, were elevated. Moreover, inhibition of PI3K and silencing of Akt expression increased the sensitivity of cells to ramentaceone-induced apoptosis. In conclusion, our results indicate that ramentaceone induces apoptosis in breast cancer cells through PI3K/Akt signaling inhibition. These findings suggest further investigation of ramentaceone as a potential therapeutic agent in breast cancer therapy, in particular HER2-positive breast cancer.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Breast Neoplasms; Caspases; Cell Line, Tumor; Cell Proliferation; Drosera; Enzyme Activation; Female; Humans; Naphthoquinones; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-bcl-2; Signal Transduction

The treatment of breast cancer-induced osteolysis remains a challenge in clinical settings. Here, we explored the effect and mechanism of combined treatment with zoledronic acid (ZA) and plumbagin (PL), a widely investigated component derived from Plumbago zeylanica, against breast cancer-induced osteoclastogenesis. We found that the combined treatment with PL and ZA suppressed cell viability of precursor osteoclasts and synergistically inhibited MDA-MB-231-induced osteoclast formation (combination index=0.28) with the abrogation of recombinant mouse receptor activator of nuclear factor-κB ligand (RANKL)-induced activation of NF-κB/MAPK (nuclear factor-κB/mitogen-activated protein kinase) pathways. Molecular docking suggested a putative binding area within c-Jun N-terminal kinase/extracellular signal-regulated kinase (JNK/Erk) protease active sites through the structural mimicking of adenosine phosphate (ANP) by the spatial combination of PL with ZA. A homogeneous time-resolved fluorescence assay further illustrated the direct competitiveness of the dual drugs against ANP docking to phosphorylated JNK/Erk, contributing to the inhibited downstream expression of c-Jun/c-Fos/NFATc-1 (nuclear factor of activated T cells, cytoplasmic, calcineurin-dependent 1). Then, in vivo testing demonstrated that the combined administration of PL and ZA attenuated breast cancer growth in the bone microenvironment. Additionally, these molecules prevented the destruction of proximal tibia, with significant reduction of tartrate-resistant acid phosphatase (TRAcP)-positive osteoclast cells and potentiation of apoptotic cancer cells, to a greater extent when combined than when the drugs were applied independently. Altogether, the combination treatment with PL and ZA could significantly and synergistically suppress osteoclastogenesis and inhibit tumorigenesis both in vitro and in vivo by simulating the spatial structure of ANP to inhibit competitively phosphorylation of c-Jun N-terminal kinase/extracellular signal-regulated kinase (JNK/Erk).

Topics: Adenine Nucleotides; Animals; Antineoplastic Combined Chemotherapy Protocols; Breast Neoplasms; Cell Line, Tumor; Diphosphonates; Disease Models, Animal; Drug Synergism; Female; Humans; Imidazoles; JNK Mitogen-Activated Protein Kinases; MAP Kinase Signaling System; Mice; Mice, Inbred BALB C; Mice, Nude; Naphthoquinones; Osteoclasts; Osteolysis; Phosphorylation; Random Allocation; Signal Transduction; Zoledronic Acid

Studies over the past decade and half have identified cancer stem cells (CSCs) to be responsible for tumorigenesis, invasion, sustenance of metastatic disease, radio- and chemo-resistance and tumor relapse. Recent reports have described the plasticity of breast CSCs (BCSCs) to shift between the epithelial and mesenchymal phenotypes via Epithelial-Mesenchymal Transition (EMT) and Mesenchymal-Epithelial Transition (MET) states as the reason for their invasive capabilities. Additionally, BRCA1 has been found to be a mammary stem cell fate determinant. However, it is not clear what would be the best marker that can be used for identifying CSCs in BRCA1 mutated cancers. Also, anticancer agents that can reduce CSC population in a BRCA1 defective condition have not been addressed so far.. Putative BCSCs were identified based on Hoechst exclusion, CD44(+)/24(-/low) expression and Aldehyde Dehydrogenase 1 (ALDH1) positivity using flow cytometry. The 'stemness' of the isolated ALDH1+ cells were analysed by immunofluorescence, western blotting for stem cell and EMT markers as well as in vitro mammosphere assays. Induction of Reactive Oxygen Species (ROS) by Plumbagin (PB) in BCSCs was assayed by Dichloro-dihydro-fluorescein diacetate (DCF-DA) staining. Ovarian cancer xenografts treated with PB were subjected to immunohistochemical analysis to study the ability of PB to target CSCs.. We have confirmed that ALDH1 positivity is the best marker for the identification of BCSCs in BRCA1-defective breast cancer cell lines when compared to the CD marker profile and Side Population (SP) analysis. BRCA1 status was observed to be a determinant of the abundance of epithelial-like (ALDH1+) or mesenchymal-like (CD44(+)/24(-/low)) BCSCs, and the reconstitution of a full length, wild type BRCA1 in HCC1937 breast cancer cells possessing a mutated BRCA1, transforms them from 'stem-like' to more 'mesenchymal'. For the first time we have shown that Plumbagin (PB), a naturally occurring naphthoquinone which is predominantly a ROS inducer, could reduce BCSCs specifically in BRCA1-defective, basal-like cancer cells.. The best marker for identifying BCSCs in BRCA1 defective condition could be ALDH1 and that BRCA1 mutated BCSCs would be mostly 'stem like' than 'mesenchymal'. Also ROS inducers like PB could reduce BCSCs in BRCA1 defective cancers.

Topics: Animals; Antineoplastic Agents, Phytogenic; Biomarkers, Tumor; BRCA1 Protein; Breast Neoplasms; Carboplatin; Cell Line, Tumor; Cell Proliferation; Epithelial-Mesenchymal Transition; Female; Humans; Inhibitory Concentration 50; Mice, SCID; Naphthoquinones; Neoplastic Stem Cells; Xenograft Model Antitumor Assays

Immunogenic cell death (ICD) of tumor cells occurs via various pathways that activate immune cell systems against cancer. Previous studies have demonstrated that shikonin (SK), a plant secondary metabolite, can confer strong pharmacological activities that activate ICD and strong immunogenicity of tumor cells. However, the exact hierarchical regulatory mechanisms including the molecular targets of SK-activated immunogenicity are still unknown. Here, the heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1) was revealed to serve as a specific protein target for SK. This binding plays a key role in SK-stimulated ICD activity and the suppression of post-transcriptional mRNA processing, including nuclear export activity of newly synthesized mRNAs in mammary carcinoma cells in vitro. Moreover, it also mechanistically mediates the anti-metastatic effect of a tumor cell lysate (TCL) vaccine, which can be readily generated from SK-treated 4T1 tumor cells (SK-TCL), and the derived tumor-immunogenicity of SK-TCL-treated dendritic cells in vivo. Together, the identification of hnRNPA1 as the intracellular molecular target provides compelling pharmacology-based knowledge for the potential clinical use of SK-induced immunogenicity. In addition, SK may also serve as a potent suppressor that interferes with specific post-transcriptional activities, a mechanism which may be useful for exploitation in cancer therapeutics.

Topics: Animals; Antineoplastic Agents; Apoptosis; Breast Neoplasms; Cancer Vaccines; Cell Line, Tumor; Dendritic Cells; Female; Heterogeneous Nuclear Ribonucleoprotein A1; Humans; Mice; Mice, Inbred BALB C; Molecular Docking Simulation; Naphthoquinones; RNA Processing, Post-Transcriptional; RNA, Messenger; Tandem Mass Spectrometry; Xenograft Model Antitumor Assays

Shikonin is a naphthoquinone isolated from the traditional Chinese medicine Lithospermum. It has been used in the treatment of various tumors. However, the effects of shikonin on such diseases have not been fully elucidated. In the present study, we detected the exosome release of a breast cancer cell line (MCF-7) with shikonin treatment and found a positive relationship between the level of secreted exosomes and cell proliferation. We next analyzed miRNA profiles in MCF-7 cells and exosomes and found that some miRNAs are specifically sorted and abundant in exosomes. Knockdown of the most abundant miRNAs in exosomes and the MCF-7 proliferation assay showed that miR-128 in exosomes negatively regulates the level of Bax in MCF-7 recipient cells and inhibits cell proliferation. These results show that shikonin inhibits the proliferation of MCF-7 cells through reducing tumor-derived exosomal miR-128. The current study suggests that shikonin suppresses MCF-7 growth by the inhibition of exosome release.

Topics: Apoptosis; Breast Neoplasms; Cell Proliferation; Exosomes; Female; Gene Expression Regulation, Neoplastic; Humans; MCF-7 Cells; MicroRNAs; Naphthoquinones

The estrogen receptor (ER) inhibitor tamoxifen reduces breast cancer mortality by 31 % and has served as the standard treatment for ER-positive breast cancers for decades. However, 50 % of advanced ER-positive cancers display de novo resistance to tamoxifen, and acquired resistance evolves in 40 % of patients who initially respond. Mechanisms underlying resistance development remain poorly understood and new therapeutic opportunities are urgently needed. Here, we report the generation and characterization of seven tamoxifen-resistant breast cancer cell lines from four parental strains.. Using high throughput drug sensitivity and resistance testing (DSRT) with 279 approved and investigational oncology drugs, exome-sequencing and network analysis, we for the first time, systematically determine the drug response profiles specific to tamoxifen resistance.. We discovered emerging vulnerabilities towards specific drugs, such as ERK1/2-, proteasome- and BCL-family inhibitors as the cells became tamoxifen-resistant. Co-resistance to other drugs such as the survivin inhibitor YM155 and the chemotherapeutic agent paclitaxel also occurred.. This study indicates that multiple molecular mechanisms dictate endocrine resistance, resulting in unexpected vulnerabilities to initially ineffective drugs, as well as in emerging co-resistances. Thus, combatting drug-resistant tumors will require patient-tailored strategies in order to identify new drug vulnerabilities, and to understand the associated co-resistance patterns.

Topics: Breast Neoplasms; Cell Line, Tumor; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Drug Screening Assays, Antitumor; Drugs, Investigational; Exome; Female; Gene Expression Regulation, Neoplastic; Gene Regulatory Networks; Genomic Instability; High-Throughput Screening Assays; Humans; Imidazoles; MCF-7 Cells; Naphthoquinones; Paclitaxel; Sequence Analysis, DNA; Small Molecule Libraries; Tamoxifen

Natural plant products are increasingly being used in cancer therapeutic studies due to their reduced normal cell toxicity. In this study, the anti-cancer properties of plumbagin, a naphthoquinone derivative extracted from the roots of Plumbago, were evaluated in breast cancer cells.. To evaluate the effects of plumbagin on breast cancer cell types, we employed a variety of techniques comprising cell viability, cell cycle assay, comet assay, western blotting, immunocytochemistry, measurement of telomerase activity, telomere restriction fragment length, quantitative fluorescence in situ hybridisation, along with gene expression analysis of untreated cells.. Plumbagin treatment induced cytotoxicity in human breast cancer cells along with cell cycle arrest, DNA damage and cell death leading to apoptosis. Plumbagin was also found to suppress the telomerase activity in cancer cells accompanied by telomere attrition. Telomere shortening was corroborated by reduced telomere fluorescence on chromosome ends and genome instability.. Together, these findings may suggest the application of plumbagin as adjuvant modality in breast cancer therapeutics.

Topics: Apoptosis; Breast Neoplasms; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Movement; Chromosome Aberrations; Clone Cells; DNA Breaks, Double-Stranded; DNA Damage; Female; Gene Expression Regulation, Neoplastic; Genomic Instability; Humans; In Situ Hybridization, Fluorescence; Naphthoquinones; Oligonucleotide Array Sequence Analysis; Telomerase; Telomere; Telomere Homeostasis; Wound Healing

This study investigated the nature and mechanism of juglone-induced apoptosis in the human breast cancer cell line MCF-7. The inhibitory effect of juglone on MCF-7 cell growth was evaluated by the dimethylthiazol tetrazolium assay. Morphological apoptotic changes were characterized using an inverted microscope, Hoechst 33258 fluorescence staining, and Giemsa staining. The rate of cell apoptosis, intracellular levels of reactive oxygen species (ROS), and mitochondrial membrane potential were detected using flow cytometry. Intracellular Ca(2+) concentrations were detected using laser scanning confocal fluorescence microscopy. Expression of the proteins Bcl-2, Bax, and cytochrome C was assessed by western blotting. Caspase-3 activity was quantified using a caspase-3 activity kit. Juglone inhibited the growth of MCF-7 cell line with an IC50 of 11.99 μM. The rates of MCF-7 cell apoptosis at 24 h after exposure to 5, 10, and 20 μM juglone were 9.29, 20.67, and 28.39%, respectively; compared to unexposed cells, juglone-exposed cells exhibited significant elevation in intracellular ROS level, decrease in mitochondrial membrane potential, and increase in intracellular Ca(2+) concentration. Juglone upregulated the expression of Bax, and downregulated the expression of Bcl-2, promoting the release of cytochrome C, thereby upregulating the activity of caspase-3. The results suggest that the mechanism of juglone-induced apoptosis in MCF-7 cells is characterized by elevated ROS levels, reduced Bcl-2 expression, increased Bax expression, decreased mitochondrial membrane potential, increased intracellular Ca(2+) concentration, outer mitochondrial-membrane rupture, cytochrome C release, and caspase-3 activation.

Topics: Apoptosis; bcl-2-Associated X Protein; Breast Neoplasms; Caspase 3; Cell Line, Tumor; Cytochromes c; Female; Humans; MCF-7 Cells; Membrane Potential, Mitochondrial; Mitochondria; Naphthoquinones; Proto-Oncogene Proteins c-bcl-2; Reactive Oxygen Species; Signal Transduction

Tamoxifen is widely used as the first line drug for estrogen receptor-positive subtype which is expressed in 70% of overall breast cancer patients. However, approximately 50% of these patients develop acquired resistance after 5 years of treatment, which is characterized by tumor recurrence and metastasis. The epithelial mesenchymal transition (EMT) is an important process in breast cancer invasion. Fundamentally, targeting the EMT represents a crucial therapeutic strategy for preventing or treating breast cancer metastasis. Plumbagin (PLB) is a natural naphthoquinone with significant anticancer effects against several types of tumor cells including breast cancer. In this study, we investigated the effect of PLB on human endocrine-resistant breast cancer cell growth, invasion and the possible mechanisms underlying such actions. PLB exhibited potent cytotoxic activity at a micromolar concentration against endocrine-resistant breast cancer cells. Interestingly, a fixed low concentration of PLB and tamoxifen combination resulted in an increase in growth inhibition in endocrine-resistant cells. In addition, PLB also significantly suppressed mesenchymal biomarker expressions that govern the EMT process, resulting in attenuated metastatic capabilities. In conclusion, PLB should be developed as a pharmacological agent for the use as a single treatment or in combination for endocrine-resistant breast cancer. Copyright © 2016 John Wiley & Sons, Ltd.

Topics: Anticoagulants; Breast Neoplasms; Cell Line, Tumor; Drug Resistance, Neoplasm; Epithelial-Mesenchymal Transition; Female; Humans; Naphthoquinones; Tamoxifen

HER2-overexpressing breast cancers account for about 30% of breast cancer occurrences and have been correlated with increased tumor aggressiveness and invasiveness. The nuclear factor-κB (NF-κB) is overexpressed in a subset of HER2-positive breast cancers and its upregulation has been associated with the metastatic potential of HER2-overexpressing tumors. The present study aimed at determining the potential of plumbagin, a naturally occurring naphthoquinone, to inhibit the invasion of HER2-overexpressing breast cancer cells and determine the involvement of NF-κB inhibition in plumbagin-mediated cell invasion suppression. In the present research we showed that plumbagin inhibited the transcriptional activity of NF-κB in HER2-positive breast cancer cells. The suppression of NF-κB activation corresponded with the inhibition of NF-κB p65 phosphorylation and downregulation of NF-κB-regulated matrix metalloproteinase 9 (MMP-9) expression. Plumbagin suppressed the invasion of HER2-overexpressing breast cancer cells and the inhibition of cell invasion was associated with the ability of plumbagin to inhibit NF-κB transcriptional activity. The silencing of NF-κB p65 increased the sensitivity of HER2-overexpressing breast cancer cells to plumbagin-induced cell invasion inhibition. NF-κB inhibition was associated with IκB kinase α (IKKα) activity suppression and inhibition of IκBα phosphorylation and degradation. The knockdown of IKKα resulted in increased sensitivity of HER2-positive cells to plumbagin-induced suppression of NF-κB transcriptional activity and expression of MMP-9. In conclusion, plumbagin inhibits the invasion of HER2-overexpressing breast cancer cells through the inhibition of IKKα-mediated NF-κB activation and downregulation of NF-κB-regulated MMP-9 expression.

Topics: Breast Neoplasms; Cell Line, Tumor; Cell Movement; Down-Regulation; Female; Humans; I-kappa B Kinase; Matrix Metalloproteinase 9; Naphthoquinones; NF-kappaB-Inducing Kinase; Phosphorylation; Protein Serine-Threonine Kinases; Receptor, ErbB-2; RNA Interference; RNA, Small Interfering; Transcription Factor RelA; Transcription, Genetic

Investigating the effects of juglone loaded P188/phospholipid mixed micelles (J-MM) in breast cancer.. In vitro cytotoxicity, apoptotic effects, in vivo therapeutic efficacy and toxicity were used to assess its antitumour effect. Uptake and imaging were used to evaluate the effect on the uptake and passive targeting.. Mixed micelle carrier enhanced the targeting and uptake by MB-231 cells. The tumour inhibition rates in tumour xenograft models for paclitaxel, juglone, J-MM (10mg/kg) and J-MM (40mg/kg) were 46%, 27%, 39% and 53%, respectively. J-MM (10mg/kg) exhibited lower toxicity compared with that by free juglone or high dose J-MM.. J-MM exhibited low toxicity, improved cellular uptake, passive targeting and anti-cancer effects in breast cancer model.

Topics: Antineoplastic Agents; Apoptosis; Breast Neoplasms; Cell Line, Tumor; Drug Carriers; Female; Humans; Micelles; Naphthoquinones; Paclitaxel; Phospholipids; Poloxamer

Cell division cycle (CDC) 25 proteins are key phosphatases regulating cell cycle transition and proliferation by regulating CDK/cyclin complexes. Overexpression of these enzymes is frequently observed in cancer and is related to aggressiveness, high-grade tumors and poor prognosis. Thus, targeting CDC25 by compounds, able to inhibit their activity, appears a good therapeutic approach. Here, we describe the synthesis of a new inhibitor (SV37) whose structure is based on both coumarin and quinone moieties. An analytical in vitro approach shows that this compound efficiently inhibits all three purified human CDC25 isoforms (IC50 1-9 µM) in a mixed-type mode. Moreover, SV37 inhibits growth of breast cancer cell lines. In MDA-MB-231 cells, reactive oxygen species generation is followed by pCDK accumulation, a mark of CDC25 dysfunction. Eventually, SV37 treatment leads to activation of apoptosis and DNA cleavage, underlining the potential of this new type of coumarin-quinone structure.

Topics: Apoptosis; Benzoquinones; Breast Neoplasms; cdc25 Phosphatases; Cell Line, Tumor; Cell Proliferation; Coumarins; Cyclin-Dependent Kinases; DNA Cleavage; Female; Humans; MCF-7 Cells; Naphthoquinones; Protein Isoforms; Reactive Oxygen Species; Viral Proteins

The aim of this study was to determine the potency and molecular mechanism of action of YM155, a first-in-class survivin inhibitor that is currently under phase I/II clinical investigations, in various drug-resistant breast cancers including the oestrogen receptor positive (ER(+) ) tamoxifen-resistant breast cancer and the caspase-3-deficient breast cancer.. The potency of YM155 in SK-BR-3, MDA-MB-231, MCF7 and its tamoxifen-resistant sublines, TamR6, TamR7, TamR8, TamC3 and TamC6, were determined by MTT assay. Western blot analysis, flow cytometric analysis, reverse transcription-PCR, fluorescent microscopy and comet assay were used to determine the molecular mechanism of action of YM155 in different breast cancer cell lines.. YM155 was equally potent towards the parental ER(+) /caspase-3-deficient MCF7 breast cancer cells and its tamoxifen-resistant sublines in vitro. The ER(-) /HER2(+) SK-BR-3 breast cancer cells and the triple-negative/caspase-3-expressing metastatic aggressive MDA-MB-231 breast cancer cells were also sensitive to YM155 with IC50 values in the low nanomolar range. Targeting survivin by YM155 modulated autophagy, induced autophagy-dependent caspase-7 activation and autophagy-dependent DNA damage in breast cancer cells. Interestingly, YM155 also induced XIAP degradation and the degradation of XIAP might play an important role in YM155-induced autophagy in breast cancer cells.. YM155 is a potent survivin inhibitor that has potential for the management of various breast cancer subtypes regardless of the expression of ER, HER2 and caspase-3. Importantly, this study provides new insights into YM155's molecular mechanism of action and therapeutic potential in the treatment of tamoxifen-resistant breast cancer.

Topics: Antineoplastic Agents; Autophagy; Breast Neoplasms; Caspase 3; Cell Line, Tumor; Cell Survival; DNA Damage; Down-Regulation; Humans; Imidazoles; Inhibitor of Apoptosis Proteins; L-Lactate Dehydrogenase; Microtubule-Associated Proteins; Naphthoquinones; Receptor, ErbB-2; Receptors, Estrogen; RNA, Small Interfering; Survivin; X-Linked Inhibitor of Apoptosis Protein

Naphthazarin (Naph, DHNQ, 5,8-dihydroxy-l,4-naphthoquinone) is one of the naturally available 1,4-naphthoquinone derivatives that are well-known for their anti-inflammatory, antioxidant, antibacterial and antitumor cytotoxic effects in cancer cells. Herein, we investigated whether Naph has effects on cell cycle arrest and apoptosis in MCF-7 human breast cancer cells exposed to ionizing radiation (IR). Naph reduced the MCF-7 cell viability in a dose-dependent manner. We also found that Naph and/or IR increased the p53-dependent p21 (CIP/WAF1) promoter activity. Noteworthy, our ChIP assay results showed that Naph and IR combined treatment activated the p21 promoter via inhibition of binding of multi-domain proteins, DNMT1, UHRF1 and HDAC1. Apoptosis and cell cycle analyses demonstrated that Naph and IR combined treatment induced cell cycle arrest and apoptosis in MCF-7 cells. Herein, we showed that Naph treatment enhances IR-induced cell cycle arrest and death in MCF-7 human breast cancer cells through the p53-dependent p21 activation mechanism. These results suggest that Naph might sensitize breast cancer cells to radiotherapy by enhancing the p53-p21 mechanism activity.

Topics: Antineoplastic Agents; Apoptosis; Breast Neoplasms; Cell Cycle Checkpoints; Cell Proliferation; Chemoradiotherapy; Cyclin-Dependent Kinase Inhibitor p21; Dose-Response Relationship, Drug; Female; Gene Expression Regulation, Neoplastic; Humans; MCF-7 Cells; Naphthoquinones; Promoter Regions, Genetic; Radiation-Sensitizing Agents

The tumor microenvironment plays a critical role in regulating breast tumor progression. Signaling between preadipocytes and breast cancer cells has been found to promote breast tumor formation and metastasis. Exosomes secreted from preadipocytes are important components of the cancer stem cell niche. Mouse preadipocytes (3T3L1) are treated with the natural antitumor compound shikonin (SK) and exosomes derived from mouse preadipocytes are co-cultured with MCF10DCIS cells. We examine how preadipocyte-derived exosomes can regulate early-stage breast cancer via regulating stem cell renewal, cell migration, and tumor formation. We identify a critical miR-140/SOX2/SOX9 axis that regulates differentiation, stemness, and migration in the tumor microenvironment. Next, we find that the natural antitumor compound SK can inhibit preadipocyte signaling inhibiting nearby ductal carcinoma in situ (DCIS) cells. Through co-culture experiments, we find that SK-treated preadipocytes secrete exosomes with high levels of miR-140, which can impact nearby DCIS cells through targeting SOX9 signaling. Finally, we find that preadipocyte-derived exosomes promote tumorigenesis in vivo, providing strong support for the importance of exosomal signaling in the tumor microenvironment. Our data also show that targeting the tumor microenvironment may assist in blocking tumor progression.

Topics: 3T3 Cells; Adipocytes; Animals; Antineoplastic Agents; Breast Neoplasms; Cell Differentiation; Cell Line, Tumor; Coculture Techniques; Exosomes; Female; Gene Expression Regulation, Neoplastic; Humans; Mice; MicroRNAs; Naphthoquinones; Neoplasm Transplantation; Neoplastic Stem Cells; Signal Transduction; SOX9 Transcription Factor

Cancer stem cells (CSCs) are responsible for aggressive tumor growth, metastasis and therapy resistance. In this study, we evaluated the effects of Shikonin (Shk) on breast cancer and found its anti-CSC potential. Shk treatment decreased the expression of various epithelial to mesenchymal transition (EMT) and CSC associated markers. Kinase profiling array and western blot analysis indicated that Shk inhibits STAT3, FAK and Src activation. Inhibition of these signaling proteins using standard inhibitors revealed that STAT3 inhibition affected CSCs properties more significantly than FAK or Src inhibition. We observed a significant decrease in cell migration upon FAK and Src inhibition and decrease in invasion upon inhibition of STAT3, FAK and Src. Combined inhibition of STAT3 with Src or FAK reduced the mammosphere formation, migration and invasion more significantly than the individual inhibitions. These observations indicated that the anti-breast cancer properties of Shk are due to its potential to inhibit multiple signaling proteins. Shk also reduced the activation and expression of STAT3, FAK and Src in vivo and reduced tumorigenicity, growth and metastasis of 4T1 cells. Collectively, this study underscores the translational relevance of using a single inhibitor (Shk) for compromising multiple tumor-associated signaling pathways to check cancer metastasis and stem cell load.

Topics: Adult; Anti-Inflammatory Agents, Non-Steroidal; Breast Neoplasms; Cell Movement; Cell Proliferation; Cell Survival; Drugs, Chinese Herbal; Epithelial-Mesenchymal Transition; Female; Focal Adhesion Kinase 1; Humans; MCF-7 Cells; Middle Aged; Naphthoquinones; Neoplasm Invasiveness; Neoplastic Stem Cells; Proto-Oncogene Proteins pp60(c-src); Signal Transduction; Spheroids, Cellular; STAT3 Transcription Factor; Tumor Burden; Tumor Cells, Cultured

Specific overexpression in cancer cells and evidence of oncogenic functions make Survivin an attractive target in cancer therapy. The small molecule compound YM155 has been described as the first "Survivin suppressant" but molecular mechanisms involved in its biological activity and its clinical potential remain obscure. We herein show that YM155 exerts single agent toxicity on primary breast cancer cells grown in an ex vivo assay preserving tumor microenvironment. In vitro assays indicate that YM155 more efficiently triggers cell death in breast cancer cells (including these with stem-cell like properties) than in non tumorigenic mammary cells. YM155-induced cell death is critically dependent on autophagy and NF-kB but independent of p53 and it coïncides with DNA damage and a DNA damage response in p53-proficient cells. Our results point out a crosstalk between NF-kB and autophagy controlling YM155-induced death in breast cancer cells and argue for the potential use of YM155 as a genotoxic agent in breast cancer therapy.

Topics: Antineoplastic Agents; Autophagy; Breast Neoplasms; Cell Death; Cell Line, Tumor; Cell Proliferation; DNA Damage; Female; Humans; Imidazoles; MCF-7 Cells; Naphthoquinones; NF-kappa B; Signal Transduction; Transfection; Xenograft Model Antitumor Assays

This study aimed to evaluate the effects of Pin1 inhibitor Juglone on proliferation, migration and the angiogenic ability of breast cancer cell line MCF7Adr. MCF7Adr cells were cultured and separately treated with Pin1 inhibitor Juglone (treatment group) and DMEM without drug (control group). The cell cycle was examined by flow cytometry. Cell migration was measured by wound-healing assay. Cyclin E protein content was detected by Western blotting. The angiogenesis factor vascular endothelial growth factor (VEGF) in cell media was determined by enzyme linked immunosorbent assay. The results showed that the percentage of cells in G2/M phase in treatment group was significantly higher than that in control group (25.5% vs. 10.1%, P<0.05), and that in G0/G1 phase and S stage in treatment group was significantly lower than that in control group (40.5% vs. 48.2%, and 33.7% vs. 41.7%, P<0.05). Cyclin E protein content in treatment group was significantly lower than that in control group (39.2 ± 7.4 vs. 100 ± 23.1, P<0.05). (A0-A24)/A0 value in treatment group was significantly lower than that in control group (23.9 ± 3.8 vs. 100 ± 14.4, P<0.05). VEGF-A, -B, and -C contents in cell media of treatment group were significantly lower than those in control group (P<0.05). It was suggested that Pin1 inhibitor Juglone can effectively inhibit the proliferation, migration and the angiogenic ability of MCF7Adr cells, and can be used as an alternative drug therapy for breast cancer.

Topics: Antineoplastic Agents; Breast Neoplasms; Cell Cycle; Cell Movement; Cell Proliferation; Cyclin E; Female; Gene Expression Regulation, Neoplastic; Humans; MCF-7 Cells; Naphthoquinones; NIMA-Interacting Peptidylprolyl Isomerase; Peptidylprolyl Isomerase; Vascular Endothelial Growth Factor A

Zoledronic acid (ZA), a bisphosphonate, is currently used in combination with chemotherapeutic agents to suppress breast cancer cell proliferation or breast cancer-induced osteolysis. The aim of this study was to investigate the effects of ZA combined with a natural anticancer compound plumbagin (PL) against human breast cancer cells in vitro.. Human breast cancer MDA-MB-231SArfp cells were treated with ZA, PL or a combination of ZA and PL. The cell growth, apoptosis and migration were evaluated using CCK-8 assay, flow cytometry and transwell assay, respectively. The expression of apoptosis-related proteins was measured using real-time PCR and Western blotting. Synergism was evaluated using Compusyn software, and the combination index (CI) and drug reduction index (DRI) values were determined.. PL or ZA alone caused mild cytotoxicity (the IC50 value at 24 h was 12.18 and above 100 μmol/L, respectively). However, the combination of ZA and PL caused a synergistic cytotoxicity (CI=0.26). The DRI values also showed a synergistic effect between PL and ZA, with actual values of 5.52 and 3.59, respectively. Furthermore, PL and ZA synergistically induced apoptosis and inhibited migration of the breast cancer cells. Moreover, the combination of ZA and PL decreased the expression of Notch-1, cleaved PARP, Bcl-2 and Bcl-xl, and increased the expression of cleaved caspase-3, CDKN1A and ID1. When the breast cancer cells were transfected with specific siRNA against Notch-1, the combination of ZA and PL markedly increased the expression of Bcl-2.. Combination of ZA and PL synergistically suppresses human breast cancer MDA-MB-231SArfp cells in vitro. PL can inhibit ZA-induced activation of the Notch-1 signaling pathway and subsequently reduce the expression of Bcl-2, thus potentiating cancer cell apoptosis.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Bone Density Conservation Agents; Breast; Breast Neoplasms; Cell Line, Tumor; Cell Movement; Diphosphonates; Drug Synergism; Female; Gene Expression Regulation, Neoplastic; Humans; Imidazoles; Naphthoquinones; Proto-Oncogene Proteins c-bcl-2; Receptor, Notch1; RNA, Small Interfering; Signal Transduction; Zoledronic Acid

Shikonin (SK), a natural naphthoquinone isolated from the Chinese medicinal herb, has been known to suppress the proliferation of several cancer cells. However, its role in the epithelial mesenchymal transition (EMT) has yet to be demonstrated. The aim of the present study was to examine the effects of SK on EMT. Lipopolysaccharide (LPS) induced EMT-like phenotypic changes, enhancing cell migration and invasion. SK markedly reduced the expression of the LPS-induced EMT markers, including N-cadherin in MDA-MB‑231 cells, and increased the expression of E-cadherin in MCF-7 cells. SK also inhibited cell migration and invasion in vitro. The effects of SK on the LPS-induced EMT were mediated by the inactivation of the NF-κB-Snail signaling pathway. The results provided new evidence that SK suppresses breast cancer cell invasion and migration by inhibiting the EMT. Therefore, SK is a potentially effective anticancer agent for breast tumors, by inhibiting metastasis.

Topics: Anti-Inflammatory Agents, Non-Steroidal; Blotting, Western; Breast Neoplasms; Cadherins; Cell Line, Tumor; Cell Movement; Cell Proliferation; Cell Survival; Dose-Response Relationship, Drug; Drugs, Chinese Herbal; Epithelial-Mesenchymal Transition; Female; Humans; Lipopolysaccharides; MCF-7 Cells; Microscopy, Fluorescence; Naphthoquinones; Snail Family Transcription Factors; Transcription Factor RelA; Transcription Factors

Breast cancer, the most common cancer in the women, is the leading cause of death. Necrotic signaling pathways will enable targeted therapeutic agents to eliminate apoptosis-resistant cancer cells. In the present study, the effect of shikonin on the induction of cell necroptosis or apoptosis was evaluated using the T-47D breast cancer cell line. The cell death modes, caspase-3 and 8 activities and the levels of reactive oxygen species (ROS) were assessed. Cell death mainly occurred through necroptosis. In the presence of Nec-1, caspase-3 mediated apoptosis was apparent in the shikonin treated cells. Shikonin stimulates ROS generation in the mitochondria of T-47D cells, which causes necroptosis or apoptosis. Induction of necroptosis, as a backup-programmed cell death pathway via ROS stimulation, offers a new strategy for the treatment of breast cancer.

Topics: Anti-Inflammatory Agents, Non-Steroidal; Apoptosis; Breast Neoplasms; Caspase 3; Cell Proliferation; Female; Humans; Mitochondria; Naphthoquinones; Necrosis; Reactive Oxygen Species; Tumor Cells, Cultured

Plumbagin [5-hydroxy- 2-methyl-1, 4-naphthaquinone] is a well-known plant derived anticancer lead compound. Several efforts have been made to synthesize its analogs and derivatives in order to increase its anticancer potential. In the present study, plumbagin and its five derivatives have been evaluated for their antiproliferative potential in one normal and four human cancer cell lines. Treatment with derivatives resulted in dose- and time-dependent inhibition of growth of various cancer cell lines. Prescreening of compounds led us to focus our further investigations on acetyl plumbagin, which showed remarkably low toxicity towards normal BJ cells and HepG2 cells. The mechanisms of apoptosis induction were determined by APOPercentage staining, caspase-3/7 activation, reactive oxygen species production and cell cycle analysis. The modulation of apoptotic genes (p53, Mdm2, NF-kB, Bad, Bax, Bcl-2 and Casp-7) was also measured using real time PCR. The positive staining using APOPercentage dye, increased caspase-3/7 activity, increased ROS production and enhanced mRNA expression of proapoptotic genes suggested that acetyl plumbagin exhibits anticancer effects on MCF-7 cells through its apoptosis-inducing property. A key highlighting point of the study is low toxicity of acetyl plumbagin towards normal BJ cells and negligible hepatotoxicity (data based on HepG2 cell line). Overall results showed that acetyl plumbagin with reduced toxicity might have the potential to be a new lead molecule for testing against estrogen positive breast cancer.

Topics: Antineoplastic Agents; Apoptosis; Breast Neoplasms; Caspase 3; Caspase 7; Cell Cycle; Cell Survival; Female; Fibroblasts; Hep G2 Cells; Humans; Male; MCF-7 Cells; Naphthoquinones; Reactive Oxygen Species; Receptors, Estrogen; Structure-Activity Relationship

Metastasis contributes to the escalating mortality rate among cancer patients worldwide. The search for novel and more effective anti-metastatic agent is crucial owing to the lack of anticancer drugs that can successfully combat metastasis. Hence, this study aims to examine the effects of 2-Methoxy-1,4-Naphthoquinone (MNQ) towards the metastasis of MDA-MB-231 cells. In invasion assays, the number of cells permeating across a Matrigel barrier was found to be decreased in a dose-dependent manner upon treatment with MNQ (0-7.5 μM). In wound-healing migration assays, MNQ exhibited dose-dependent inhibition of cell migration in which significant reduction in the zone of closure was observed as compared to untreated controls. Furthermore, the proteolytic activity of a pivotal metastatic mediator, matrix metalloproteinase-9 (MMP-9) was also downregulated by MNQ as determined by gelatin zymography. This study reports for the first time, the ability of MNQ to inhibit the invasion and migration characteristics of a highly metastatic MDA-MB-231 cancer cell line.

Topics: Antineoplastic Agents; Breast Neoplasms; Cell Line, Tumor; Cell Movement; Collagen; Dose-Response Relationship, Drug; Down-Regulation; Drug Combinations; Female; Humans; Laminin; Matrix Metalloproteinase 9; Naphthoquinones; Neoplasm Invasiveness; Neoplasm Metastasis; Proteoglycans

To investigate the effects of plumbagin, a naphthoquinone derived from the medicinal plant Plumbago zeylanica, on human breast cancer cell growth and the cancer cell-induced osteolysis in the bone microenvironment of mice.. Human breast cancer cell subline MDA-MB-231SA with the ability to spread and grow in the bone was tested. The cell proliferation was determined using the CCK-8 assay. Apoptosis was detected with Annexin V/PI double-labeled flow cytometry. Red fluorescent protein-labeled MDA-MB-231SArfp cells were injected into the right tibia of female BALB/c-nu/nu mice. Three days after the inoculation, the mice were injected with plumbagin (2, 4, or 6 mg/kg, ip) 5 times per week for 7 weeks. The growth of the tumor cells was monitored using an in vivo imaging system. After the mice were sacrificed, the hind limbs were removed for radiographic and histological analyses.. Plumbagin (2.5-20 μmol/L) concentration-dependently inhibited the cell viability and induced apoptosis of MDA-MB-231SA cells in vitro (the IC50 value of inhibition of cell viability was 14.7 μmol/L). Administration of plumbagin to breast cancer bearing mice delayed the tumor growth by 2-3 weeks and reduced the tumor volume by 44%-74%. The in vivo imaging study showed that plumbagin dose-dependently inhibited MDA-MB-231SArfp cell growth in bone microenvironment. Furthermore, X-ray images and micro-CT study demonstrated that plumbagin reduced bone erosion area and prevented a decrease in bone tissue volume. Histological studies showed that plumbagin dose-dependently inhibited the breast cancer cell growth, enhanced the cell apoptosis and reduced the number of TRAcP-positive osteoclasts.. Plumbagin inhibits the cell growth and induces apoptosis in human breast cancer cells in mice bone microenvironment, leading to significant reduction in osteolytic lesions caused by the tumor cells.

Topics: Animals; Antineoplastic Agents, Phytogenic; Bone Neoplasms; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Cell Survival; Dose-Response Relationship, Drug; Female; Humans; Mice; Mice, Inbred BALB C; Mice, Nude; Naphthoquinones; Osteoclasts; Tumor Microenvironment

The objective of this research was to simultaneously analyze protein adducts of quinonoid metabolites of naphthalene and endogenous estrogen in serum albumin (Alb) derived from healthy pregnant women in Taiwan and to explore the correlations among them. The isomeric forms of cysteinyl adducts of naphthoquinones, including 1,2-naphthoquinone (1,2-NPQ) and 1,4-naphthoquinone (1,4-NPQ) as well as estrogen quinones, including estrogen-2,3-quinones (E2-2,3-Q) and estrogen-3,4-quinones (E2-3,4-Q), are characterized after adduct cleavage. Results showed that the median levels of cysteinyl adducts of 1,2-NPQ and 1,4-NPQ on serum albumin were 249-390 and 16.0-24.8 pmol g(-1), respectively. Logged levels of 1,2-NPQ-Alb were correlated with logged levels of 1,4-NPQ-Alb (correlation coefficient r = 0.551, P < 0.001). Cysteinyl adducts of E2-2,3-Q-1-S-Alb, E2-2,3-Q-4-S-Alb, and E2-3,4-Q-2-S-Alb were detected in all subjects with median levels at 275-435, 162-288, and 197-254 pmol g(-1), respectively. We also found a positive relationship between logged levels of E2-2,3-Q-4-S-Alb and those of E2-3,4-Q-2-S-Alb (r = 0.770, P < 0.001).We noticed that median levels of E2-2,3-Q-derived adducts (E2-2,3-Q-1-S-Alb plus E2-2,3-Q-4-S-Alb) in pregnant women were greater than those of E2-3,4-Q-2-S-Alb (∼2-3-fold). Taken together, this evidence lends further support to the theme that cumulative concentration of E2-3,4-Q is a significant predictor of the risk of breast cancer. Furthermore, we noticed that levels of 1,2-NPQ-Alb are positively associated with levels of E2-3,4-Q-2-S-Alb (r = 0.522, P < 0.001) and those of E2-2,3-Q-4-S-Alb (r = 0.484, P < 0.001). Overall, this evidence suggests that environmental exposure to polycyclic aromatic hydrocarbons may modulate estrogen homeostasis and enhance the production of reactive quinone species of endogenous estrogen in humans.

Topics: Adult; Benzoquinones; Biomarkers; Body Burden; Breast Neoplasms; Environmental Exposure; Estradiol; Female; Humans; Naphthalenes; Naphthoquinones; Polycyclic Aromatic Hydrocarbons; Pregnancy; Quinones; Serum Albumin; Taiwan

Shikonin, a small-molecule natural product which inhibits the activity of pyruvate kinase M2 (PKM2), has been studied as an anti-cancer drug candidate in human cancer models. Here, our results demonstrate that shikonin is able to sensitize human breast cancer cells to chemotherapy by paclitaxel (taxol). Human breast adenocarcinoma MBA-MD-231 cells, which have higher levels of PKM2 expression and activity compared with MCF-7 cells, were selected to study further. The concentrations of shikonin and taxol were first selected at which they did not significantly induce cytotoxicity when treated alone, whereas the combination induced apoptosis. Surprisingly, PKM2 activity was decreased by shikonin, but not by the combination treatment. To identify the potential targets of this combination, human phospho-kinase antibody array analysis was performed and results indicated that the combination treatment inhibited the activation of ERK, Akt, and p70S6 kinases, which are known to contribute to breast cancer progression. Finally, how the combination affects breast cancer cell growth in vivo was tested using a xenograft tumor model. The results indicated that shikonin plus taxol prolonged animal survival and reduced tumor size than the vehicle treatment group. In summary, our results suggest that shikonin has a potential as an adjuvant for breast cancer therapy.

Topics: Adenocarcinoma; Animals; Antineoplastic Agents; Antineoplastic Agents, Phytogenic; Apoptosis; Breast Neoplasms; Cell Line, Tumor; Drug Interactions; Drug Therapy, Combination; Female; Heterografts; Humans; Mice; Mice, Nude; Naphthoquinones; Paclitaxel

Shikonin, a natural naphthoquinone isolated from a traditional Chinese medicinal herb, has been reported to promote tumor cell death. However, there are few reports concerning its effect on metastasis-related cell invasion and migration behavior. In the present study, we investigated the effect of shikonin on human breast cancer invasion and migration. We found that shikonin inhibited phorbol 12-myristate 13-acetate (PMA)-induced cell migration and invasion in MCF-7 breast cancer cells, which was correlated with modulation of matrix metalloproteinase-9 (MMP-9) through suppression of both expression and proteolytic and promoter activity. We also found that shikonin inhibited both MMP-9 expression and promoter activity in MDA-MB‑231 cells with high metastatic potential. These results indicated that shikonin induces the suppression of migration and invasion through modulation of MMP-9 in human breast cancer cells. Therefore, shikonin may be a potential anticancer drug for human breast cancer therapy.

Topics: Breast Neoplasms; Cell Movement; Female; Gene Expression Regulation, Neoplastic; Humans; Matrix Metalloproteinase 9; Matrix Metalloproteinase Inhibitors; MCF-7 Cells; Naphthoquinones; Neoplasm Invasiveness; Signal Transduction; Tetradecanoylphorbol Acetate

We have synthesized, structurally characterized and examined cytotoxicity of novel plumbagin hydrazones against estrogen and progesterone receptor positive (ER+/PR+) MCF-7 and triple negative MDA-MB-231 breast cancer cell lines in order to evaluate the potential of these novel phytochemical analogs. Compounds were docked into the protein cavity of p50-subunit of NF-κB protein revealing better fit and better binding energies than the parent plumbagin compound. This was also reflected in their superior cytotoxicities which were found to be mediated by inhibition of NF-κB expression. These compounds can provide a starting point for the development of novel drug molecules against triple negative breast cancers.

Topics: Antineoplastic Agents; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Female; Humans; Hydrazones; MCF-7 Cells; Models, Molecular; Molecular Structure; Naphthoquinones; Structure-Activity Relationship

The molecular determinants of breast cancer resistance to first-line anthracycline-containing chemotherapy are unknown.. We examined the response to doxorubicin of organotypic cultures of primary human breast tumors ex vivo with respect to cell proliferation, DNA damage and modulation of apoptosis. Samples were analyzed for genome-wide modulation of cell death pathways, differential activation of p53, and the role of survivin family molecules in drug resistance. Rational drug combination regimens were explored by high-throughput screening, and validated in model breast cancer cell types.. Doxorubicin treatment segregated organotypic human breast tumors into distinct Responder or Non Responder groups, characterized by differential proliferative index, stabilization of p53, and induction of apoptosis. Conversely, tumor histotype, hormone receptor or human epidermal growth factor receptor-2 (HER2) status did not influence chemotherapy sensitivity. Global analysis of cell death pathways identified survivin and its alternatively spliced form, survivin-ΔEx3 as uniquely overexpressed in Non Responder breast tumors. Forced expression of survivin-ΔEx3 preserved cell viability and prevented doxorubicin-induced apoptosis in breast cancer cell types. High-throughput pharmacologic targeting of survivin family proteins with a small-molecule survivin suppressant currently in the clinic (YM155) selectively potentiated the effect of doxorubicin, but not other chemotherapeutics in breast cancer cell types, and induced tumor cell apoptosis.. Survivin family proteins are novel effectors of doxorubicin resistance in chemotherapy-naive breast cancer. The incorporation of survivin antagonist(s) in anthracycline-containing regimens may have improved clinical activity in these patients.

Topics: Alternative Splicing; Antibiotics, Antineoplastic; Antineoplastic Agents; Antineoplastic Agents, Phytogenic; Apoptosis; Breast Neoplasms; Camptothecin; Cell Line, Tumor; Cell Proliferation; Cell Survival; DNA Damage; Doxorubicin; Drug Resistance, Neoplasm; Etoposide; Female; High-Throughput Screening Assays; Humans; Imidazoles; Inhibitor of Apoptosis Proteins; MCF-7 Cells; Naphthoquinones; Paclitaxel; Receptor, ErbB-2; Survivin; Tumor Suppressor Protein p53

Gla-rich protein (GRP) was described in sturgeon as a new vitamin-K-dependent protein (VKDP) with a high density of Gla residues and associated with ectopic calcifications in humans. Although VKDPs function has been related with γ-carboxylation, the Gla status of GRP in humans is still unknown. Here, we investigated the expression of recently identified GRP spliced transcripts, the γ-carboxylation status, and its association with ectopic calcifications, in skin basal cell and breast carcinomas. GRP-F1 was identified as the predominant splice variant expressed in healthy and cancer tissues. Patterns of γ-carboxylated GRP (cGRP)/undercarboxylated GRP (ucGRP) accumulation in healthy and cancer tissues were determined by immunohistochemistry, using newly developed conformation-specific antibodies. Both GRP protein forms were found colocalized in healthy tissues, while ucGRP was the predominant form associated with tumor cells. Both cGRP and ucGRP found at sites of microcalcifications were shown to have in vitro calcium mineral-binding capacity. The decreased levels of cGRP and predominance of ucGRP in tumor cells suggest that GRP may represent a new target for the anticancer potential of vitamin K. Also, the direct interaction of cGRP and ucGRP with BCP crystals provides a possible mechanism explaining GRP association with pathological mineralization.

Topics: alpha-Galactosidase; Breast Neoplasms; Calcinosis; Carcinoma, Basal Cell; Female; Humans; Naphthoquinones; Osteocalcin; Skin Neoplasms; Vitamin K

Cancer stem cells (CSCs), a small and elusive population of undifferentiated cancer cells within tumors that drive tumor growth and recurrence, are believed to resemble normal stem cells. Although surrogate markers have been identified and compelling CSC theoretical models abound, actual proof for the existence of CSCs can only be had retrospectively. Hence, great store has come to be placed in isolating CSCs from cancers for in-depth analysis. On the other hand, although induced pluripotent stem cells (iPSCs) hold great promise for regenerative medicine, concern exists over the inadvertent co-transplantation of partially or undifferentiated stem cells with tumorigenic capacity. Here we demonstrate that the introduction of defined reprogramming factors (OCT4, SOX2, Klf4 and c-Myc) into MCF-10A nontumorigenic mammary epithelial cells, followed by partial differentiation, transforms the bulk of cells into tumorigenic CD44(+)/CD24(low) cells with CSC properties, termed here as induced CSC-like-10A or iCSCL-10A cells. These reprogrammed cells display a malignant phenotype in culture and form tumors of multiple lineages when injected into immunocompromised mice. Compared with other transformed cell lines, cultured iCSCL-10A cells exhibit increased resistance to the chemotherapeutic compounds, Taxol and Actinomycin D, but higher susceptibility to the CSC-selective agent Salinomycin and the Pin1 inhibitor Juglone. Restored expression of the cyclin-dependent kinase inhibitor p16INK4a abrogated the CSC properties of iCSCL-10A cells, by inducing cellular senescence. This study provides some insight into the potential oncogenicity that may arise via cellular reprogramming, and could represent a valuable in vitro model for studying the phenotypic traits of CSCs per se.

Topics: Animals; Breast Neoplasms; CD24 Antigen; Cell Differentiation; Cell Line, Tumor; Cell Proliferation; Cellular Reprogramming; Cellular Senescence; Cyclin-Dependent Kinase Inhibitor p16; Dactinomycin; Drug Resistance, Neoplasm; Epithelial Cells; Female; Gene Expression Regulation, Neoplastic; Humans; Hyaluronan Receptors; Induced Pluripotent Stem Cells; Kruppel-Like Factor 4; Kruppel-Like Transcription Factors; Mammary Glands, Human; MCF-7 Cells; Mice; Mice, Inbred BALB C; Mice, Nude; Naphthoquinones; Neoplastic Stem Cells; Octamer Transcription Factor-3; Paclitaxel; Proto-Oncogene Proteins c-myc; Pyrans; SOXB1 Transcription Factors; Spheroids, Cellular

β-Lapachone is a phytochemotherapeutic originally isolated from Lapacho tree whose extract has been used medicinally for centuries. It is well known that NAD(P)H:quinone oxidoreductase (NQO1) activity is the principal determinant of β-Lapachone cytotoxicity. As NQO1 is overexpressed in most common carcinomas, recent investigations suggest its potential application against cancer. Photodynamic therapy (PDT) is a clinically approved and rapidly developing cancer treatment. PDT involves the administration of photosensitizer (PS) followed by local illumination with visible light of specific wavelength. In the presence of oxygen molecules, the light illumination of PS can lead to a series of photochemical reactions and consequently the generation of cytotoxic reactive oxygen species (ROS). It has been reported that β-Lapachone synergistically interacts with ionizing radiation, hyperthermia and cisplatin and that the sensitivity of cells to β-Lapachone is closely related to the activity of NQO1. So, the present study aimed to investigate the feasibility of PDT to increase the anticancer effect of β-Lapachone by up-regulating NQO1 expression on breast cancer MCF-7c3 cells. NQO1 expression was evaluated by Western blot analysis at different times after PDT using ME-ALA as PS. The cytotoxicity of the photodynamic treatment and β-Lapachone alone or in combination was determined by MTT assay and the combination index (CI)-isobologram method and the dose reduction index (DRI) analysis were used to assess the effect of drug combinations. Our studies for the first time demonstrated that the expression of NQO1 is induced 24h after photodynamic treatment. The sensitivity of cancer cells to β-Lapachone treatment increased 24h after PDT and a synergistic inhibitory effect on MCF-7c3 cells was showed. Taken together, these results lead us to conclude that the synergistic interaction between β-Lapachone and PDT in killing cells was consistent with the up-regulation of NQO1. The combination of β-Lapachone and PDT is a potentially promising modality for the treatment of cancer.

Topics: Antineoplastic Agents, Phytogenic; Breast Neoplasms; Female; Humans; Light; MCF-7 Cells; NAD(P)H Dehydrogenase (Quinone); Naphthoquinones; Photochemotherapy; Phytotherapy; Plant Extracts; Reactive Oxygen Species; Tabebuia; Up-Regulation

Improving patient outcome by personalized therapy involves a thorough understanding of an agent's mechanism of action. β-Lapachone (clinical forms, Arq501/Arq761) has been developed to exploit dramatic cancer-specific elevations in the phase II detoxifying enzyme NAD(P)H:quinone oxidoreductase (NQO1). NQO1 is dramatically elevated in solid cancers, including primary and metastatic [e.g., triple-negative (ER-, PR-, Her2/Neu-)] breast cancers. To define cellular factors that influence the efficacy of β-lapachone using knowledge of its mechanism of action, we confirmed that NQO1 was required for lethality and mediated a futile redox cycle where ∼120 moles of superoxide were formed per mole of β-lapachone in 2 minutes. β-Lapachone induced reactive oxygen species (ROS), stimulated DNA single-strand break-dependent poly(ADP-ribose) polymerase-1 (PARP1) hyperactivation, caused dramatic loss of essential nucleotides (NAD(+)/ATP), and elicited programmed necrosis in breast cancer cells. Although PARP1 hyperactivation and NQO1 expression were major determinants of β-lapachone-induced lethality, alterations in catalase expression, including treatment with exogenous enzyme, caused marked cytoprotection. Thus, catalase is an important resistance factor and highlights H2O2 as an obligate ROS for cell death from this agent. Exogenous superoxide dismutase enhanced catalase-induced cytoprotection. β-Lapachone-induced cell death included apoptosis-inducing factor (AIF) translocation from mitochondria to nuclei, TUNEL+ staining, atypical PARP1 cleavage, and glyceraldehyde 3-phosphate dehydrogenase S-nitrosylation, which were abrogated by catalase. We predict that the ratio of NQO1:catalase activities in breast cancer versus associated normal tissue are likely to be the major determinants affecting the therapeutic window of β-lapachone and other NQO1 bioactivatable drugs.

Topics: Breast Neoplasms; Catalase; DNA Breaks, Single-Stranded; DNA Damage; Female; Gene Expression Regulation, Neoplastic; Humans; Hydrogen Peroxide; NAD(P)H Dehydrogenase (Quinone); Naphthoquinones; Necrosis; Poly (ADP-Ribose) Polymerase-1; Poly(ADP-ribose) Polymerases; Reactive Oxygen Species

Human arylamine N-acetyltransferase 1 (hNAT1) has become an attractive potential biomarker for estrogen-receptor-positive breast cancers. We describe here the mechanism of action of a selective non-covalent colorimetric biosensor for the recognition of hNAT1 and its murine homologue, mNat2, over their respective isoenzymes, leading to new opportunities in diagnosis. On interaction with the enzyme, the naphthoquinone probe undergoes an instantaneous and striking visible color change from red to blue. Spectroscopic, chemical, molecular modelling and biochemical studies reported here show that the color change is mediated by selective recognition between the conjugate base of the sulfonamide group within the probe and the conjugate acid of the arginine residue within the active site of both hNAT1 and mNat2. This represents a new mechanism for selective biomarker sensing and may be exploited as a general approach to the specific detection of biomarkers in disease.

Topics: Animals; Arylamine N-Acetyltransferase; Biomarkers, Tumor; Breast Neoplasms; Catalytic Domain; Color; Female; Humans; Isoenzymes; Mice; Naphthoquinones; Protein Binding

Phospholipid and Tween(®) 80 mixed micelles were investigated as injectable nanocarriers for the natural anticancer compound, plumbagin (PBG), with the aim to improve anticancer efficiency. PBG-loaded mixed micelles were fabricated by self-assembly; composition being optimized using 3(2) factorial design.. Optimized mixed micelles were spherical and 46 nm in size. Zeta potential, drug loading and encapsulation efficiency were 5.04 mV, 91.21 and 98.38% respectively. Micelles demonstrated sustained release of PBG. Micelles caused a 2.1-fold enhancement in vitro antitumor activity of PBG towards MCF-7 cells. Micelles proved safe for intravenous injection as PBG was stable at high pH; micelle size and encapsulation efficiency were retained upon dilution.. Developed mixed micelles proved potential nanocarriers for PBG in cancer chemotherapy.

Topics: Antineoplastic Agents, Phytogenic; Blood Proteins; Breast Neoplasms; Cell Survival; Chemistry, Pharmaceutical; Delayed-Action Preparations; Drug Carriers; Drug Stability; Female; Hemolysis; Humans; Kinetics; MCF-7 Cells; Micelles; Nanoparticles; Nanotechnology; Naphthoquinones; Particle Size; Phospholipids; Polysorbates; Protein Binding; Solubility; Technology, Pharmaceutical

It has been shown earlier that plumbagin, a naturally occurring naphthaquinone has specific anticancer activity in BRCA1 blocked ovarian cancer cells. Plumbagin can induce estrogen dependent cell signaling and apoptosis in BRCA1 blocked ovarian cancer cells. Being a reactive oxygen species (ROS) generator and apoptosis inducing agent, plumbagin has immense potential as a promising anticancer agent. In this study we analyzed whether there would be increased anticancer activity if the positions of the functional groups on plumbagin were altered and further to analyze the detailed molecular mechanism of action of the lead molecule. Methods like MTT assay, apoptosis analysis by flow cytometry, assessment of mitochondrial membrane potential-Δψm , suppression subtractive hybridization, microarray, molecular docking and estrogen receptor-DNA binding activity by electrophoresis mobility shift assay (EMSA) were adopted for assessing the anticancer activity. Consequently we found that, plumbagin was the most potent anticancer agent when compared to structurally related compounds. The anti-cancer activities were in the order plumbagin > 1,4-naphthaquinone > juglone > lawsone > menadione. Molecular docking studies showed that plumbagin could be well docked in the receptor ligand complex of TRAIL-DR5 complexes to activate the extrinsic pathway of apoptosis. Since the antiproliferative activity of plumbagin could be reduced by inhibiting ERα, we speculated that plumbagin interferes with the binding of ERα to ERE and we confirmed this by EMSA. This study clearly indicates that plumbagin can induce multiple pathways of apoptosis and cell cycle arrest in BRCA1 blocked cells compared to unblocked cells.

Topics: Antineoplastic Agents, Phytogenic; BRCA1 Protein; Breast Neoplasms; Cell Cycle Checkpoints; Drug Screening Assays, Antitumor; Estrogen Receptor alpha; Female; Gene Knockout Techniques; Humans; Membrane Potential, Mitochondrial; Molecular Docking Simulation; Naphthoquinones; Ovarian Neoplasms; Poly(ADP-ribose) Polymerases; Response Elements; Structure-Activity Relationship; Transcriptome

Naphtho[1,2-b]furan-4,5-dione (NFD), a bioactive component of Avicennia marina, has been demonstrated to display anti-cancer activity. Activation of epidermal growth factor receptor (EGFR)-induced signaling pathway has been correlated with cancer metastasis in various tumors, including breast carcinoma. We use EGF as a metastatic inducer of MDA-MB-231 cells to investigate the effect of NFD on cell migration and invasion. NFD suppressed EGF-mediated protein levels of c-Jun and c-Fos, and reduced MMP-9 expression and activity, concomitantly with a marked inhibition on cell migration and invasion without obvious cellular cytotoxicity. NFD abrogated EGF-induced phosphorylation of EGF receptor (EGFR) and phosphatidylinositol 3-kinase (PI3K)/Akt. The specific PI3K inhibitor, wortmannin, blocked significantly EGF-induced cell migration and invasion. Furthermore, the EGFR inhibitor AG1478 inhibited EGF-induced MMP-9 expression, cell migration and invasion, as well as the activation of PI3K/Akt, suggesting that PI3K/Akt activation occur downstream of EGFR activation. These findings suggest that NFD inhibited the EGF-induced invasion and migration of MDA-MB-231 cells via EGFR-dependent PI3K/Akt signaling, leading to the down-regulation of MMP-9 expression. These results provide a novel mechanism to explain the role of NFD as a potent anti-metastatic agent in MDA-MB-231 cells.

Topics: Androstadienes; Antineoplastic Agents; Breast Neoplasms; Cell Cycle; Cell Line, Tumor; Cell Movement; Cell Proliferation; Epidermal Growth Factor; ErbB Receptors; Female; Humans; Matrix Metalloproteinase 9; Naphthoquinones; Neoplasm Invasiveness; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Transcription Factor AP-1; Wortmannin; Wound Healing

β-Lapachone (β-Lap) is a 1,2-orthonaphthoquinone that selectively induces cell death in human cancer cells through NAD(P)H:quinone oxidoreductase-1 (NQO1). NQO1 is overexpressed in a variety of tumors, as compared to normal adjacent tissue. However, the low solubility and non-specific distribution of β-Lap limit its suitability for clinical assays. We formulated β-Lap in an optimal random methylated-β-cyclodextrin/poloxamer 407 mixture (i.e., β-Lap ternary system) and, using human breast adenocarcinoma MCF-7 cells and immunodeficient mice, performed in vitro and in vivo evaluation of its anti-tumor effects on proliferation, cell cycle, apoptosis, DNA damage, and tumor growth. This ternary system is fluid at room temperature, gels over 29 °C, and provides a significant amount of drug, thus facilitating intratumoral delivery, in situ gelation, and the formation of a depot for time-release. Administration of β-Lap ternary system to MCF-7 cells induces an increase in apoptosis and DNA damage, while producing no changes in cell cycle. Moreover, in a mouse xenograft tumor model, intratumoral injection of the system significantly reduces tumor volume, while increasing apoptosis and DNA damage without visible toxicity to liver or kidney. These anti-tumoral effects and lack of visible toxicity make this system a promising new therapeutic agent for breast cancer treatment.

Topics: Adenocarcinoma; Animals; Antineoplastic Agents; Apoptosis; Breast Neoplasms; Cell Line, Tumor; Cyclodextrins; DNA Damage; Drug Delivery Systems; Female; Humans; Mice; Mice, SCID; Naphthoquinones; Poloxamer; Rheology; Temperature; Xenograft Model Antitumor Assays

Bone loss is one of the major complications of advanced cancers such as breast cancer, prostate cancer, and multiple myeloma; agents that can suppress this bone loss have therapeutic potential. Extensive research within the last decade has revealed that RANKL, a member of the tumor necrosis factor superfamily, plays a major role in cancer-associated bone resorption and thus is a therapeutic target. We investigated the potential of vitamin K3 analogue plumbagin (derived from Chitrak, an Ayurvedic medicinal plant) to modulate RANKL signaling, osteoclastogenesis, and breast cancer-induced osteolysis. Plumbagin suppressed RANKL-induced NF-κB activation in mouse monocytes, an osteoclast precursor cell, through sequential inhibition of activation of IκBα kinase, IκBα phosphorylation, and IκBα degradation. Plumbagin also suppressed differentiation of these cells into osteoclasts induced either by RANKL or by human breast cancer or human multiple myeloma cells. When examined for its ability to prevent human breast cancer-induced bone loss in animals, plumbagin (2 mg/kg body weight) administered via the intraperitoneal route significantly decreased osteolytic lesions, resulting in preservation of bone volume in nude mice bearing human breast tumors. Overall, our results indicate that plumbagin, a vitamin K analogue, is a potent inhibitor of osteoclastogenesis induced by tumor cells and of breast cancer-induced osteolytic metastasis through suppression of RANKL signaling.

Topics: Animals; Antineoplastic Agents, Phytogenic; Blotting, Western; Bone Neoplasms; Bone Resorption; Breast Neoplasms; Cell Line; Cell Line, Tumor; Female; Humans; I-kappa B Proteins; Macrophages; Mice; Mice, Inbred BALB C; Mice, Nude; Naphthoquinones; NF-kappa B; NF-KappaB Inhibitor alpha; Osteoclasts; Osteogenesis; Osteolysis; RANK Ligand; Signal Transduction; Xenograft Model Antitumor Assays

Diospyrin diethylether (D7), a bisnaphthoquinonoid derivative, exhibited an oxidative stress-dependent apoptosis in several human cancer cells and tumor models. The present study was aimed at evaluation of the increase in cytosolic calcium [Ca(2+)](c) leading to the apoptotic cell death triggered by D7 in MCF7 human breast carcinoma cells. A phosphotidylcholine-specific phospholipase C (PC-PLC) inhibitor, viz. U73122, and an antioxidant, viz. N-acetylcysteine, could significantly prevent the D7-induced rise in [Ca(2+)](c) and PC-PLC activity. Using an endoplasmic reticulum (ER)-Ca(2+) mobilizer (thapsigargin) and an ER-IP3R antagonist (heparin), results revealed ER as a major source of [Ca(2+)](c) which led to the activation of calpain and caspase12, and cleavage of fodrin. These effects including apoptosis were significantly inhibited by the pretreatment of Bapta-AM (a cell permeable Ca(2+)-specific chelator), or calpeptin (a calpain inhibitor). Furthermore, D7-induced [Ca(2+)](c) was found to alter mitochondrial membrane potential and induce cytochrome c release, which was inhibited by either Bapta-AM or ruthenium red (an inhibitor of mitochondrial Ca(2+) uniporter). Thus, these results provided a deeper insight into the D7-induced redox signaling which eventually integrated the calcium-dependent calpain/caspase12 activation and mitochondrial alterations to accentuate the induction of apoptotic cell death.

Topics: Acetylcysteine; Antineoplastic Agents; Apoptosis; Breast Neoplasms; Calcium; Calcium Channels; Carcinoma; Cell Line, Tumor; Chelating Agents; Cytosol; Egtazic Acid; Endoplasmic Reticulum; Estrenes; Female; Humans; Mitochondria; Naphthoquinones; Oxidation-Reduction; Phosphodiesterase Inhibitors; Pyrrolidinones; Ruthenium Red; Type C Phospholipases

Topics: Antineoplastic Agents; Apoptosis; Breast Neoplasms; Calcium; Carcinoma; Endoplasmic Reticulum; Female; Humans; Mitochondria; Naphthoquinones

Novel plumbagin hydrazonates were prepared, structurally characterized and evaluated for anti-proliferative activity against estrogen receptor-positive MCF-7 and triple negative MDA-MB-231 and MDA-MB-468 breast cancer cell lines which exhibited superior inhibitory activity than parent plumbagin compound. Molecular docking studies indicated that hydroxyl groups on plumbagin and hydrazonate side chain favor additional hydrogen bonding interactions with amino acid residues in p50-subunit of NF-κB protein and these compounds inhibited NF-κB expression which may be responsible for the enhanced anti-proliferative activity. These compounds were found to be more effective against triple negative breast cancer cells and might serve as a starting point for building future strategies against triple negative breast cancers which are known for their increased drug resistance and poor prognosis of breast cancer patients.

Topics: Antineoplastic Agents; Antineoplastic Agents, Phytogenic; Binding Sites; Breast Neoplasms; Cell Line, Tumor; Female; Humans; Hydrazones; Hydrogen Bonding; Naphthoquinones; NF-kappa B; Protein Binding; Structure-Activity Relationship

Bone metastasis is a common and serious consequence of breast cancer. Bidirectional interaction between tumor cells and the bone marrow microenvironment drives a so-called 'vicious cycle' that promotes tumor cell malignancy and stimulates osteolysis. Targeting these interactions and pathways in the tumor-bone microenvironment has been an encouraging strategy for bone metastasis therapy. In the present study, we examined the effects of plumbagin on breast cancer bone metastasis. Our data indicated that plumbagin inhibited cancer cell migration and invasion, suppressed the expression of osteoclast-activating factors, altered the cancer cell induced RANKL/OPG ratio in osteoblasts, and blocked both cancer cell- and RANKL-stimulated osteoclastogenesis. In mouse model of bone metastasis, we further demonstrated that plumbagin significantly repressed breast cancer cell metastasis and osteolysis, inhibited cancer cell induced-osteoclastogenesis and the secretion of osteoclast-activating factors in vivo. At the molecular level, we found that plumbagin abrogated RANKL-induced NF-κB and MAPK pathways by blocking RANK association with TRAF6 in osteoclastogenesis, and by inhibiting the expression of osteoclast-activating factors through the suppression of NF-κB activity in breast cancer cells. Taken together, our data demonstrate that plumbagin inhibits breast tumor bone metastasis and osteolysis by modulating the tumor-bone microenvironment and that plumbagin may serve as a novel agent in the treatment of tumor bone metastasis.

Topics: Actins; Animals; Antigens, Differentiation; Antineoplastic Agents; Bone and Bones; Bone Density Conservation Agents; Bone Neoplasms; Breast Neoplasms; Cell Differentiation; Cell Line, Tumor; Cell Survival; Cytokines; Enzyme Activation; Female; Gene Expression; Humans; Inhibitory Concentration 50; Macrophages; Mice; Mice, Inbred BALB C; Mice, Nude; Mitogen-Activated Protein Kinases; Naphthoquinones; Neoplasm Invasiveness; NF-kappa B; Osteoclasts; Osteolysis; Protein Binding; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Signal Transduction; TNF Receptor-Associated Factor 6; Tumor Microenvironment; Xenograft Model Antitumor Assays

Drug-induced haploinsufficiency (DIH) in yeast has been considered a valuable tool for drug target identification. A plant metabolite, plumbagin, has potent anticancer activity via reactive oxygen species (ROS) generation. However, the detailed molecular targets of plumbagin for ROS generation are not understood. Here, using DIH and heterozygous deletion mutants of the fission yeast Schizosaccharomyces pombe, we identified 1, 4-phopshatidylinositol 5-kinase (PI5K) its3 as a new molecular target of plumbagin for ROS generation. Plumbagin showed potent anti-proliferative activity (GI(50); 10 µM) and induced cell elongation and septum formation in wild-type S. pombe. Furthermore, plumbagin dramatically increased the intracellular ROS level, and pretreatment with the ROS scavenger, N-acetyl cysteine (NAC), protected against growth inhibition by plumbagin, suggesting that ROS play a crucial role in the anti-proliferative activity in S. pombe. Interestingly, significant DIH was observed in an its3-deleted heterozygous mutant, in which ROS generation by plumbagin was higher than that in wild-type cells, implying that its3 contributes to ROS generation by plumbagin in this yeast. In MCF7 human breast cancer cells, plumbagin significantly decreased the level of a human ortholog, 1, 4-phopshatidylinositol 5-kinase (PI5K)-1B, of yeast its3, and knockdown of PI5K-1B using siPI5K-1B increased the ROS level and decreased cell viability. Taken together, these results clearly show that PI5K-1B plays a crucial role in ROS generation as a new molecular target of plumbagin. Moreover, drug target screening using DIH in S. pombe deletion mutants is a valuable tool for identifying molecular targets of anticancer agents.

Topics: Antineoplastic Agents; Breast Neoplasms; Cell Death; Cell Proliferation; Cell Survival; Down-Regulation; Drug Screening Assays, Antitumor; Female; Gene Knockdown Techniques; Haploinsufficiency; Heterozygote; Humans; MCF-7 Cells; Models, Biological; Mutation; Naphthoquinones; Phosphotransferases (Alcohol Group Acceptor); Reactive Oxygen Species; RNA, Small Interfering; Schizosaccharomyces

Invasive lobular carcinoma (ILC) and its variants represent 5% to 15% of all invasive breast cancers diagnoses annually. AS a serine/threonine kinase, mammalian target of rapamycin (mTOR) is often a downstream effector of PI3K/Akt (phosphatidyl inositol 3-kinase/protein kinase B) signaling pathway in breasts and many types of cancer cells. Therefore, agents that target mTOR in direct or indirect manner are being developed in anti-cancer therapy.. In this study, our objective here was to explore more crosstalk pathway with mTOR signaling pathway.. We collected pathways data from published database, then based on bioinformatics methods we analyzed the significant pathways in the database, additionally, the crosstalk pathways were also analyzed which were defined as those pathways which have the overlapping genes with each other.. As we expected, the results showed that Notch signaling pathway (hsa04330), Regulation of autophagy (hsa04140), and Adipocytokine signaling pathway (hsa04920) were linked to mTOR signaling pathway. All of them have been demonstrated participate in breast cancer progression.. We obtained some key pathways that crosstalked with mTOR signaling pathway, we hope our study could provide novel therapeutic approaches for breast cancer.

Topics: Adipokines; Autophagy; Breast Neoplasms; Carcinoma, Lobular; Female; Humans; Naphthoquinones; Signal Transduction; TOR Serine-Threonine Kinases

Metastatic triple negative breast cancer [TNBC, with negative expression of estrogen and progesterone receptors and no overexpression of HER2/neu (ErbB-2)] remains a major therapeutic challenge because of its poor overall prognosis and lack of optimal targeted therapies. Survivin has been implicated as an important mediator of breast cancer cell growth and dysfunctions in apoptosis, and its expression correlates with a higher incidence of metastases and patient mortality; thus, survivin is an attractive target for novel anti-cancer agents. In previous studies, we identified YM155 as a small molecule that selectively suppresses survivin expression. YM155 inhibits the growth of a wide range of human cancer cell lines. Tumor regression induced by YM155 is associated with decreased intratumoral survivin expression, increased apoptosis and a decreased mitotic index. In the present study, we evaluated the antitumor efficacy of YM155 both in vitro and in vivo using preclinical TNBC models. We found that YM155 suppressed survivin expression, including that of its splice variants (survivin 2B, δEx3 and 3B), resulting in decreased cellular proliferation and spontaneous apoptosis of human TNBC cells. In a mouse xenograft model, continuous infusion of YM155 led to the complete regression of subcutaneously established tumors. Furthermore, YM155 reduced spontaneous metastases and significantly prolonged the survival of animals bearing established metastatic tumors in the MDA-MB-231-Luc-D3H2-LN orthotopic model. These results suggest that the survivin-suppressing activity of YM155 may offer a novel therapeutic option for patients with metastatic TNBC.

Topics: Animals; Antineoplastic Agents; Breast Neoplasms; Caspase 3; Cell Line, Tumor; Down-Regulation; Enzyme Activation; Female; Humans; Imidazoles; Inhibitor of Apoptosis Proteins; Mice; Mice, SCID; Naphthoquinones; Neoplasm Metastasis; Receptor, ErbB-2; Receptors, Estrogen; Receptors, Progesterone; Repressor Proteins; Survivin; Xenograft Model Antitumor Assays

Increasing evidence indicates that the interaction between the CXC chemokine receptor-4 (CXCR4) and its ligand CXCL12 is critical in the process of metastasis that accounts for more than 90% of cancer-related deaths. Thus, novel agents that can downregulate the CXCR4/CXCL12 axis have therapeutic potential in inhibiting cancer metastasis.. In this report, we investigated the potential of an agent, plumbagin (5-hydroxy-2-methyl-1, 4-naphthoquinone), for its ability to modulate CXCR4 expression and function in various tumor cells using Western blot analysis, DNA binding assay, transient transfection, real time PCR analysis, chromatin immunoprecipitation, and cellular migration and invasion assays.. We found that plumbagin downregulated the expression of CXCR4 in breast cancer cells irrespective of their HER2 status. The decrease in CXCR4 expression induced by plumbagin was not cell type-specific as the inhibition also occurred in gastric, lung, renal, oral, and hepatocellular tumor cell lines. Neither proteasome inhibition nor lysosomal stabilization had any effect on plumbagin-induced decrease in CXCR4 expression. Detailed study of the underlying molecular mechanism(s) revealed that the regulation of the downregulation of CXCR4 was at the transcriptional level, as indicated by downregulation of mRNA expression, inhibition of NF-κB activation, and suppression of chromatin immunoprecipitation activity. In addition, using a virtual, predictive, functional proteomics-based tumor pathway platform, we tested the hypothesis that NF-κB inhibition by plumbagin causes the decrease in CXCR4 and other metastatic genes. Suppression of CXCR4 expression by plumbagin was found to correlate with the inhibition of CXCL12-induced migration and invasion of both breast and gastric cancer cells.. Overall, our results indicate, for the first time, that plumbagin is a novel blocker of CXCR4 expression and thus has the potential to suppress metastasis of cancer.

Topics: Antineoplastic Agents, Phytogenic; Breast Neoplasms; Cell Line, Tumor; Cell Movement; Chemokine CXCL12; Computer Simulation; Down-Regulation; Female; Gene Expression Regulation, Neoplastic; Genes, Reporter; Humans; Luciferases; Models, Biological; Naphthoquinones; Neoplasm Invasiveness; NF-kappa B; Protein Binding; Receptors, CXCR4; Stomach Neoplasms; Transcription, Genetic

β-lapachone (β-lap), has been known to cause NQO1-dependnet death in cancer cells and sensitize cancer cells to ionizing radiation (IR). We investigated the mechanisms underlying the radiosensitization caused by β-lap.. β-lap enhanced the effect of IR to cause clonogenic cells in NQO1(+)-MDA-MB-231 cells but not in NQO1(-)-MDA-MB-231 cells. β-lap caused apoptosis only in NQO1(+) cells and not in NQO1(-) cells and it markedly increased IR-induced apoptosis only in NQO1(+) cells. Combined treatment of NQO1(+) cells induced ROS generation, triggered ER stress and stimulated activation of ERK and JNK. Inhibition of ROS generation by NAC effectively attenuated the activation of ERK and JNK, induction of ER stress, and subsequent apoptosis. Importantly, inhibition of ERK abolished ROS generation and ER stress, whereas inhibition of JNK did not, indicating that positive feedback regulation between ERK activation and ROS generation triggers ER stress in response to combined treatment. Furthermore, prevention of ER stress completely blocked combination treatment-induced JNK activation and subsequent apoptotic cell death. In addition, combined treatment efficiently induced the mitochondrial translocation of cleaved Bax, disrupted mitochondrial membrane potential, and the nuclear translocation of AIF, all of which were efficiently blocked by a JNK inhibitor. Caspases 3, 8 and 9 were activated by combined treatment but inhibition of these caspases did not abolish apoptosis indicating caspase activation played a minor role in the induction of apoptosis.. β-lap causes NQO1-dependent radiosensitization of cancer cells. When NQO1(+) cells are treated with combination of IR and β-lap, positive feedback regulation between ERK and ROS leads to ER stress causing JNK activation and mitochondrial translocation of cleaved Bax. The resultant decrease in mitochondrial membrane leads to translocation of AIF and apoptosis.

Topics: Active Transport, Cell Nucleus; Antineoplastic Agents; Apoptosis; Apoptosis Inducing Factor; bcl-2-Associated X Protein; Breast Neoplasms; Cell Line, Tumor; Cell Nucleus; Chemoradiotherapy; Endoplasmic Reticulum Stress; Enzyme Activation; Extracellular Signal-Regulated MAP Kinases; Feedback, Physiological; Female; Humans; JNK Mitogen-Activated Protein Kinases; Membrane Potential, Mitochondrial; Mitochondria; Molecular Targeted Therapy; NAD(P)H Dehydrogenase (Quinone); Naphthoquinones; Radiation-Sensitizing Agents; Reactive Oxygen Species

Glutathione-S-transferase (GST) is a cytoplasmic protein responsible for detoxification, but the effect of the enzyme on cell biological events, including proliferation and migration, has never been reported. Thus, we evaluated the detoxification effect of in vitro-applied GST on cancer cell proliferation and migration. Assays for proliferation and migration of human breast cancer cells in the presence of GST were carried out. Binding of GST on the surface of the cancer cells was studied by flow cytometry. Detoxification through GST pathway was studied in the presence of shikonin. The effective dosage of GST in enhancement of cell proliferation was 10-50 nM, and the cell migration could be significantly enhanced after 6 hours in the presence of 2-50 nM GST. Therefore, overall cell proliferation and migration could be enhanced in the presence of 10nM or greater concentration of GST, and 15 μM shikonin-induced toxification of the cancer cells could be neutralized by 1.0 μM GST. Flow cytometry showed that GST directly bound to the surface of the cancer cells, and this was confirmed by fluorescence confocal microscopic observation. It is concluded that human class π-GST enhances proliferation and migration of human breast cancer cells by means of direct binding to the cell surface and maintaining cell viability by detoxification.

Topics: Breast Neoplasms; Cell Death; Cell Line, Tumor; Cell Membrane; Cell Movement; Cell Proliferation; Cell Survival; Female; Flow Cytometry; Glutathione Transferase; Humans; Metabolic Detoxication, Phase II; Microscopy, Confocal; Naphthoquinones; Protein Binding; Recombinant Proteins

Cancer cells reprogram their metabolism due to genetic alteration to compensate for increased energy demand and enhanced anabolism, cell proliferation, and protection from oxidative damage. Here, we assessed the cytotoxicity of three dimeric naphthoquinones against the glycolytic MCF-7 versus the oxidative MDA-453 breast carcinoma cell lines. Dimeric naphthoquinones 1 and 2 impaired MDA-453, but not MCF-7, cell growth at IC(50)=15 μM. Significant increase in reactive oxygen species, decrease in oxygen consumption and ATP production were observed in MDA-453 cells but not in MCF-7 cell. These findings suggest that oxidative stress and mitochondrial dysfunction are mechanisms by which these agents exert their cytotoxic effects. Cyclic voltammetry and semi-empirical molecular orbital calculations further characterized the electrochemical behavior of these compounds. These results also suggest that dimeric naphthoquinones may be used to selectively target cancer cells that depend on oxidative phosphorylation for energy production and macromolecular synthesis.

Topics: Breast Neoplasms; Cell Growth Processes; Cell Line, Tumor; Female; Humans; Naphthoquinones; Oxidative Stress; Reactive Oxygen Species

Several reports have demonstrated the anticancer activities of plumbagin, a naphthoquinone derivative isolated from plants belonging to Plumbaginaceae family. However, to the best of our knowledge, there are no reports which describe gold nanoconjugation with plumbagin, even though plumbagin is considered to be a promising therapeutic agent. In this report, we demonstrate the fabrication and characterization of gold nanoparticles conjugated with plumbagin (AuPB) that can reduce the toxicity of the latter, and their capacity for cellular localization and generation of reactive oxygen species. The anticancer activity and ability of plumbagin to produce reactive oxygen species was studied and compared with that of bromoderivatives of 1,4 naphthoquinones such as 2-bromo-1,4-naphthoquinone (2-BNQ) and 2,3-dibromo-1, 4-naphthoquinone (2,3-DBNQ) and their gold nanoconjugates. Plumbagin and bromoderivatives of 1,4 naphthoquinones in the form of gold nanoconjugates showed reduced cytotoxicity and apoptosis compared with the pristine compounds, ie, plumbagin, 2-BNQ, and 2,3-DBNQ. Interestingly, we observed that the gold nanoparticles could quench the reactive oxygen species-generating capacity of plumbagin, 2-BNQ, and 2,3-BNQ, which is one of the main mechanisms of action of the naphthoquinones. Therefore, it can be concluded that conjugation with gold nanoparticles can reduce the cytotoxicity of these compounds.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Female; Fluoresceins; Gold; Histocytochemistry; Humans; Metal Nanoparticles; Naphthoquinones; Reactive Oxygen Species; Tumor Suppressor Protein p53

Shikonin (SK) has been isolated and identified as a key bioactive component in an herbal plant, Shikon (gromwell). In this study, we investigated antiestrogen activity of SK in breast cancer cells. In human breast cancer cells, we observed that treatment with SK inhibits tumor cell growth in estrogen receptor alpha (ERalpha)-positive, but not ERalpha-negative breast cancer cells. Estrogen-dependent cell growth was inhibited by co-treatment with SK. A potential molecular mechanism by which SK inhibits estrogen action was explored. We found that SK has no effect on ERalpha mRNA expression, but decreases its protein level. This effect is associated with an increase in ubiquitinated ERalpha for degradation. Our results suggest that SK downregulates ERalpha protein through a proteasome-mediated pathway. We also found that the treatment with SK inhibits estrogen-induced estrogen response elements reporter gene activity. Furthermore, SK inhibits recruitment of ERalpha at the estrogen-dependent gene promoters, and subsequently suppresses gene expression. Finally, co-treatment with SK enhanced sensitivity of breast cancer cells to endocrine therapy. Collectively, our studies suggested that SK has a potential for antihormone therapy in ERalpha-positive breast cancer cells, and should serve as a target for new drug developments.

Topics: Breast Neoplasms; Cell Line, Tumor; Chromatin Immunoprecipitation; Estrogen Receptor alpha; Estrogen Receptor Modulators; Female; Gene Expression; Humans; Immunoblotting; Naphthoquinones; Response Elements; Reverse Transcriptase Polymerase Chain Reaction; Transcription, Genetic

Naphtho[1,2-b]furan-4,5-dione (NFD), prepared from 2-hydroxy-1,4-naphthoquinone and chloroacetaldehyde in an efficient one-pot reaction, exhibits an anti-carcinogenic effect. NFD-induced apoptosis in MDA-MB-231 cells, as indicated by the accumulation of sub-G1 population, externalization of phosphatidylserine, loss of mitochondrial membrane potential (DeltaPsim) with subsequent release of cytochrome c, and activation of both capase-9 and caspase-3. This correlated with up-regulation in Bax and Bad, and down-regulation of various anti-apoptotic proteins, including Bcl-2, Bcl-X(L), Mcl-1, and survivin in NFD-treated cells. In the analysis of signal transduction pathway, NFD suppressed the phosphorylation of JAK2 in MDA-MB-231 cells without altering the expression of JAK2 protein. Activation of STAT3, Src, and PI3K/Akt were also inhibited by NFD. Moreover, the JAK2 inhibitor AG490 blocked JAK2, STAT3, Src, PI3K, and Akt activation, whereas both Src inhibitor PP2 and PI3K inhibitor wortmannin did not affect JAK2 activation. This suggests that STAT3, Src, and PI3K/Akt are downstream molecules of the JAK2 signaling pathway. AG490 treatment also mimics the cytotoxic effects of NFD. Taken together, these results indicate that NFD disrupts JAK2 pathway and induces apoptosis in MDA-MB-231 cells.

Topics: Antineoplastic Agents; Apoptosis; Breast Neoplasms; Cell Line, Tumor; Female; Humans; Inhibitor of Apoptosis Proteins; Janus Kinase 2; Naphthoquinones; Phosphatidylinositol 3-Kinases; Phosphorylation; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-bcl-2; src-Family Kinases; STAT3 Transcription Factor

Endocrine therapies, which inhibit estrogen receptor signaling, are the most common and effective treatments for estrogen receptoralpha-positive breast cancer. However, the utility of these agents is limited by the frequent development of resistance, and the precise mechanisms underlying endocrine therapy resistance remain incompletely understood. Here, we demonstrate that peptidyl-prolyl isomerase Pin1 is an important determinant of resistance to tamoxifen and show that Pin1 increases E2F-4- and Egr-1-driven expression of LC-3 as a result of an increased interaction with and phosphorylation of MEK1/2. In human tamoxifen-resistant breast cancer, our results show a significant correlation between Pin1 overexpression and high levels of LC-3. Promoter activity as well as expression levels of Pin1 were drastically higher in tamoxifen-resistant MCF7 cells than control MCF7 cells, as were levels of LC-3 mRNA and protein, an autophagy marker. Pin1(-/-) mouse embryonic fibroblasts showed lower 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced MEK1/2 phosphorylation than Pin1(+/+) mouse embryonic fibroblasts. Silencing of Pin1 expression inhibited TPA-induced MEK1/2 phosphorylation in MCF7 cells. Moreover, PD98059, a specific inhibitor of MEK1/2, and juglone, a potent Pin1 inhibitor, significantly suppressed the TPA-induced expression of E2F-4 as well as Egr-1 transcription factors, which control LC-3 gene expression. Importantly, 4-hydroxy tamoxifen, when used in combination with silencing of Pin1 or LC-3, increased cleaved poly(ADP-ribose) polymerase and DNA fragmentation to inhibit cologenic growth of MCF7 cells. We therefore link the Pin1-MEK pathway and LC-3-mediated tamoxifen resistance and show the therapeutic potential of Pin1 in the treatment of tamoxifen-resistant breast cancer.

Topics: Animals; Antineoplastic Agents; Breast Neoplasms; Cell Line, Tumor; Drug Resistance, Neoplasm; Enzyme Inhibitors; Female; Flavonoids; Gene Expression Regulation, Neoplastic; Humans; Mice; Microtubule-Associated Proteins; Naphthoquinones; NIMA-Interacting Peptidylprolyl Isomerase; Peptidylprolyl Isomerase; Tamoxifen

A study of the components of the fruits of Kigelia pinnata was undertaken to identify compounds with potential growth inhibitory activity against human melanoma cells, since extracts from the fruits of this plant have been described in traditional medicine to have application in the treatment of skin cancer and other skin ailments. A bioactivity-guided fractionation process yielded a number of crude fractions, which demonstrated cytotoxicity in vitro against human melanoma cells. Compounds isolated and identified included the isocoumarins, demethylkigelin (1) and kigelin (2), fatty acids, oleic (3) and heneicosanoic acids (4), the furonaphthoquinone, 2-(1-hydroxyethyl)-naphtho[2,3-b]furan-4,9-dione (5), and ferulic acid (6). A number of structurally related synthetic compounds were also tested using the MTT assay. The most potent series of these compounds, the furonaphthoquinones, also demonstrated a cytotoxic effect in two human breast cancer cell lines tested.

Topics: Antineoplastic Agents, Phytogenic; Bignoniaceae; Breast Neoplasms; Cell Line, Tumor; Female; Fruit; Growth Inhibitors; Humans; Melanoma; Naphthoquinones; Phytotherapy; Plant Extracts; Skin Neoplasms

Exposure to higher levels of estrogen produces genotoxic metabolites that can stimulate mammary tumorigenesis. Induction of NF-E2-related factor 2 (NRF2)-dependent detoxifying enzymes (e.g., NAD(P)H-quinone oxidoreductase 1 (NQO1)) is considered an important mechanism of protection against estrogen-associated carcinogenesis because they would facilitate removal of toxic estrogens. Here, we studied the impact of estrogen-receptor (ER) signaling on NRF2-dependent gene transcription. In luciferase assay experiments using the 5-flanking region of the human NQO1 gene promoter, we observe that ERα ligand-binding domain (LBD) is required for estrogen inhibition of NQO1 promoter activity in estrogen-dependent breast cancer cells. Chromatin immunoprecipitation (ChIP) assay shows that estrogen recruits ERα and a class III histone deacetylase SIRT1 at the NQO1 promoter, leading to inhibition of NQO1 transcription. Inhibition of ERα expression by the antiestrogen shikonin reverses the inhibitory effect of estrogen on NQO1 expression. As a consequence, a chemoprevention study was undertaken to monitor the impact of shikonin on DNA lesions and tumor growth. Treatment of MCF-7 breast cancer cells with shikonin inhibits estrogen-induced 8-hydroxy-2-deoxyguanosine (8-OHdG), a marker of DNA damage. NQO1 deficiency promotes estrogen-dependent tumor formation, and shikonin inhibits estrogen-dependent tumor growth in an NQO1-dependent manner in MCF-7 xenografts. These results suggest that estrogen-receptor signaling pathway has an inhibitory effect on NRF2-dependent enzymes. Moreover, shikonin reverses the inhibitory effects of estrogen on this pathway and may contribute to breast cancer prevention.

Topics: Animals; Antineoplastic Agents, Phytogenic; Binding Sites; Breast Neoplasms; Cell Line, Tumor; Chromatin Immunoprecipitation; DNA Damage; Dose-Response Relationship, Drug; Estradiol; Estrogen Receptor alpha; Female; Gene Expression Regulation, Neoplastic; Humans; Mice; Mice, Nude; NAD(P)H Dehydrogenase (Quinone); Naphthoquinones; NF-E2-Related Factor 2; Ovariectomy; Promoter Regions, Genetic; RNA, Messenger; Signal Transduction; Sirtuin 1; Transcription, Genetic; Transfection; Tumor Burden; Xenograft Model Antitumor Assays

Mitochondria and associated oxidative stress have been shown to play critical roles in apoptotic death induced by various stress agents. Previously, we reported the antitumor property of diospyrin (D1), a plant-derived bisnaphthoquinonoid, and its diethylether derivative (D7), which was found to cause apoptotic death in human cancer cell lines. The present study aims to explore the relevant mechanism of apoptosis involving generation of cellular reactive oxygen species (ROS) by D7 in human breast carcinoma (MCF-7) cells. It was found that while D7 inhibited the proliferation of tumor cells, the associated apoptosis induced by D7 was prevented by treating the cells with N-acetyl-L-cysteine (NAC), an antioxidant, and cyclosporine A (CsA), an inhibitor of mitochondrial permeability transition (MPT). Experiments using suitable inhibitors also demonstrated that D7 could alter the electron flow in mitochondrial electron transport chain by affecting target(s) between complex I and complex III, and indicated the probable site of D7-induced generation of ROS. These results were further supported by confocal microscopic observation on changes in mitochondrial organization and shape in cells treated with D7. Taken together, the results of our study clearly suggested that the apoptosis induced by D7 would involve alteration of MPT, cardiolipin peroxidation, migration of Bax from cytosol to mitochondria, decreased expression of Bcl-2, and release of cytochrome c, indicating oxidative mechanism at the mitochondrial level in the tumor cells.

Topics: Acetylcysteine; Allopurinol; Animals; Antimycin A; Apoptosis; bcl-2-Associated X Protein; Breast Neoplasms; Cardiolipins; Cell Line, Tumor; Cyclosporine; Cytochromes c; Female; Free Radical Scavengers; Humans; Membrane Potential, Mitochondrial; Mitochondria; Naphthoquinones; Oxidation-Reduction; Oxidative Stress; Proto-Oncogene Proteins c-bcl-2; Reactive Oxygen Species; Rotenone; Uncoupling Agents; Vitamin K 3

A series of shikonin analogues with side chain variants have been synthesized and evaluated for antitumor activity. These novel analogues show a broad spectrum of in vitro cytotoxicity against various cancer cell lines. Additionally, some analogues were also found to have the ability to decrease the expression level of HIF-1alpha in breast cancer cells MDA-MB-231 under hypoxia. The features of these analogues suggest their potential in cancer therapy.

Topics: Antineoplastic Agents; Breast Neoplasms; Cell Line, Tumor; Chemistry, Pharmaceutical; Drug Design; Drug Screening Assays, Antitumor; HeLa Cells; HL-60 Cells; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Inhibitory Concentration 50; Models, Chemical; Naphthoquinones

Breast cancer is the most frequent cancer and the second leading cause of cancer deaths in women today. A number of 1,4-naphthoquinone derivatives have been found to possess significant pharmacological effects associated with marked antimicrobial and antitumor activities. In the present study, the in vitro effect of 2,3-dichloro-5,8-dimethoxy-1,4-naphthoquinone (DCDMNQ) was evaluated on estrogen-positive MCF-7 and estrogen-negative MDA-MB-436 and Hs-578T human breast cancer cell lines. Moreover, the in vitro activity of this compound on cell cycle regulation and apoptosis were evaluated.. Established methods of cell viability, cell cycle, Western blot and apoptosis were used.. The effect of DCDMNQ on MCF-7, MDA-MB-436 and Hs-578T cells revealed significant antitumor activities with IC(50)s, of 0.6 +/- 0.02, 1.4 +/- 0.25 and 3.1 +/- 0.4 microM respectively. Cell cycle analysis showed that DCDMNQ inhibited progression through the cell cycle in MCF-7 and MDA-MB-436 cell lines in a time-dependent manner. DCDMNQ arrested cells in the S-phase of the cell cycle with the greatest proportion of cells in the S-phase by day 5. This cell-cycle arrest was corroborated by inhibition of topoisomerase I induced by DCDMNQ. These findings were further validated using Western blot analysis of retinoblastoma protein time-dependent phosphorylation. Furthermore, DCDMNQ induced apoptosis in both estrogen-positive and -negative cell lines in a time-dependent manner. However, the highest percentages of apoptotic cells were observed in the MDA-MB-436 cell line.. Although the mechanism of action of DCDMNQ has not been completely elucidated, it appears that this compound can inhibit topoisomerase I in a concentration-dependent manner. These promising results to explore novel naphthoquinone analogues as potential breast cancer agents. This study suggests that DCDMNQ may have an impact on treatment of estrogen-positive and -negative breast cancer while protecting the bone marrow.

Topics: Antineoplastic Agents; Apoptosis; Blotting, Western; Breast Neoplasms; Cell Cycle; Cell Line, Tumor; Cell Survival; DNA Topoisomerases, Type I; Flow Cytometry; Humans; Naphthoquinones; Topoisomerase I Inhibitors

Steroid sulfatase (STS) has an important role in regulating the biosynthesis of estrogen within breast tumors. We aimed to investigate whether shikonin, an ingredient of Lithospermum erythrorhizon, could modulate STS expression in breast cancer cells. By MTT assay, shikonin inhibited the cell proliferation of breast cancer cells MCF-7 and SK-BR-3. Moreover, by semi-quantitative/quantitative reverse transcription polymerase chain reaction and dual-luciferase reporter based bioluminescent measurements, the mRNA and enzymatic activity levels of STS were decreased after shikonin treatment. Concluding, shikonin could act as a selective estrogen enzyme modulator by down-regulating the STS expression.

Topics: Antineoplastic Agents; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Down-Regulation; Female; Gene Expression Regulation, Enzymologic; Humans; Lithospermum; Naphthoquinones; RNA, Messenger; Steryl-Sulfatase

Breast cancer remains the major cause of cancer-related deaths in women world-wide. The heterogeneity of breast cancer has further complicated the progress of target-based therapies. Triple negative breast cancers, lacking estrogen receptor, progesterone receptor and the Her-2/neu (ErbB2), represent a highly aggressive breast cancer subtype, that are difficult to treat. Pleiotropic agents, such as those found in nature, can target receptor-positive as well as receptor-negative cancer cells, suggesting that such agents could have significant impact in breast cancer prevention and/or therapy. Plumbagin (5-hydroxy-2-methyl-1, 4-naphthoquinone) is one such agent which has anti-tumor activity against several cancers. However, its mechanism of action against breast cancer is not clearly understood. We hypothesized that plumbagin may act as an effective agent against breast cancer especially triple negative breast cancer. We tested our hypothesis using ER-positive MCF-7 and ER-negative MDA-MB-231 (triple negative) breast cancer cells, and we found that plumbagin significantly inhibits the growth of breast cancer cells with no effect on normal breast epithelial cells. We also found that plumbagin induces apoptosis with concomitant inactivation of Bcl-2 and the DNA binding activity of NF-kappaB. Bcl-2 over-expression resulted in attenuation of plumbagin-induced effects, suggesting that the inhibition of cell growth and induction of apoptosis by plumbagin is in part due to inactivation of NF-kappaB/Bcl-2 pathway. To our knowledge, this is the first report, showing mechanistic and cancer cell specific apoptosis-inducing effects of plumbagin in breast cancer cells, suggesting the potential role of plumbagin in the prevention and/or treatment of breast cancer.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Autophagy; Breast Neoplasms; Cell Line, Tumor; Cell Survival; Female; Humans; Naphthoquinones; NF-kappa B; Proto-Oncogene Proteins c-bcl-2

Radiotherapy is the primary line of cancer treatment for cervical cancer and is known to induce cell death in tumors. Radiotherapy is however limited by the total dose that can be given without damaging normal tissue. Plumbagin, a naturally occurring naphthaquinone, has been reported to have free radical producing properties. Hence we hypothesized that plumbagin could also have properties that could modify effects of radiation on cervical cancer cells. Radiation in combination with plumbagin may thus have treatment augmenting effects. Results from our studies have shown that a lower dose of radiation in combination with plumbagin could induce apoptosis more effectively compared to a higher dose of radiation alone. Plumbagin in combination with 2 Gy of radiation was very effective in inducing apoptosis, when compared to a higher radiation dose of 10 Gy alone. This combination also showed a fivefold increase in the activation of caspase 3 in C33A cells. Activation of effector caspases confirms that the induction of apoptosis by irradiation and plumbagin involves caspase-dependent pathways. Expression of apoptotic regulatory molecules Bcl-2, Bax and Survivin was also modulated by plumbagin in combination with radiation. In summary, this study shows that a combination of plumbagin and radiation augmented cell growth inhibition compared to higher radiation dose alone, thus indicating that plumbagin may be a potential radiosensitizer acting through the induction of apoptosis.

Topics: Apoptosis; Breast; Breast Neoplasms; Cell Line, Tumor; Cell Survival; Female; Gamma Rays; HeLa Cells; Humans; Membrane Potentials; Mitochondrial Membranes; Naphthoquinones; Radiation-Sensitizing Agents; Uterine Cervical Neoplasms

Mitogen-activated protein kinase phosphatase (MKP)-1 is a dual-specificity phosphatase that negatively regulates the activity of mitogen-activated kinases and that is overexpressed in human tumors. Contemporary studies suggest that induction of MKP-1 during chemotherapy may limit the efficacy of clinically used antineoplastic agents. Thus, MKP-1 is a rational target to enhance anticancer drug activity, but suitable small-molecule inhibitors of MKP-1 are currently unavailable. Here, we have used a high-content, multiparameter fluorescence-based chemical complementation assay for MKP activity in intact mammalian cells to evaluate the cellular MKP-1 and MKP-3 inhibitory activities of four previously described, quinone-based, dual-specificity phosphatase inhibitors, that is, NSC 672121, NSC 95397, DA-3003-1 (NSC 663284), and JUN-1111. All compounds induced formation of reactive oxygen species in mammalian cells, but only one (NSC 95397) inhibited cellular MKP-1 and MKP-3 with an IC(50) of 13 mumol/L. Chemical induction of MKP-1 by dexamethasone protected cells from paclitaxel-induced apoptosis but had no effect on NSC 95397. NSC 95397 phenocopied the effects of MKP-1 small inhibitory RNA by reversing the cytoprotective effects of dexamethasone in paclitaxel-treated cells. Isobologram analysis revealed synergism between paclitaxel and NSC 95397 only in the presence of dexamethasone. The data show the power of a well-defined cellular assay for identifying cell-active inhibitors of MKPs and support the hypothesis that small-molecule inhibitors of MKP-1 may be useful as antineoplastic agents under conditions of high MKP-1 expression.

Topics: Antineoplastic Combined Chemotherapy Protocols; Breast Neoplasms; Cell Survival; Cytoprotection; Dexamethasone; Drug Evaluation, Preclinical; Drug Resistance, Neoplasm; Drug Synergism; Dual Specificity Phosphatase 1; Dual Specificity Phosphatase 6; HeLa Cells; Humans; Mitogen-Activated Protein Kinase Phosphatases; Models, Biological; Naphthoquinones; Paclitaxel; Quinones; Reactive Oxygen Species; Tumor Cells, Cultured

Fatty acid synthase (FAS) is a major lipogenic enzyme catalyzing the synthesis of long-chain saturated fatty acids. Most breast cancers require lipogenesis for growth. Here, we demonstrated the effects of theanaphthoquinone (TNQ), a member of the thearubigins generated by the oxidation of theaflavin (TF-1), on the expression of FAS in human breast cancer cells. TNQ was found to suppress the EGF-induced expression of FAS mRNA and FAS protein in MDA-MB-231 cells. Expression of FAS has previously been shown to be regulated by the SREBP family of transcription factors. In this study, we demonstrated that the EGF-induced nuclear translocation of SREBP-1 was blocked by TNQ. Moreover, TNQ also modulated EGF-induced ERK1/2 and Akt phosphorylation. Treatment of MDA-MB-231 cells with PI 3-kinase inhibitors, LY294002 and Wortmannin, inhibited the EGF-induced expression of FAS and nuclear translocation of SREBP-1. Treatment with TNQ inhibited EGF-induced EGFR/ErbB-2 phosphorylation and dimerization. Furthermore, treatment with kinase inhibitors of EGFR and ErbB-2 suggested that EGFR/ErbB-2 activation was involved in EGF-induced FAS expression. In constitutive FAS expression, TNQ inhibited FAS expression and Akt autophosphorylation in BT-474 cells. The PI 3-kinase inhibitors and tyrosine kinase inhibitors of EGFR and ErbB-2 also reduced constitutive FAS expression. In addition, pharmacological blockade of FAS by TNQ decreased cell viability and induced cell death in BT-474 cells. In summary, our findings suggest that TNQ modulates FAS expression by the regulation of EGFR/ErbB-2 pathways and induces cell death in breast cancer cells.

Topics: Blotting, Western; Breast Neoplasms; Cell Death; Cell Line, Tumor; Cell Nucleus; Cell Survival; Down-Regulation; Epidermal Growth Factor; ErbB Receptors; fas Receptor; Fatty Acid Synthases; Female; Flow Cytometry; Genes, erbB-2; Humans; Immunoprecipitation; Naphthoquinones; Oncogene Protein v-akt; Phosphatidylinositol 3-Kinases; Phosphorylation; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction; Sterol Regulatory Element Binding Protein 1; Stimulation, Chemical; Translocation, Genetic; Tyrosine

The development of radio-resistant tumor cells might be overcome by the use of tumor selective cytotoxic agents in combination with radiation treatment of cancer. Thus, we are exploring the radiomodifying potential of D7, a tumor-inhibitory compound derived from a plant product, diospyrin, in breast carcinoma cells, MCF-7. The present study indicated that D7 could enhance the radiation-induced cytotoxicity and apoptosis through down-regulation of the anti-apoptotic Bcl-2 and COX-2 gene expression, and up-regulation of pro-apoptotic genes, like p53 and p21. The higher expression of PUMA, a pro-apoptotic protein was also observed in the combination treatment. Effect of D7 on up-regulation of p21 expression in irradiated MCF-7 cells was concomitant with the cell cycle arrest in the G1 phase. Thus, it was concluded that D7 could sensitize the effect of radiation in breast carcinoma by regulating the gene expression involved in cell cycle and apoptosis.

Topics: Breast Neoplasms; Carcinoma; Cell Cycle; Cell Line, Tumor; Cyclooxygenase 2; Drug Evaluation, Preclinical; Gene Expression Regulation, Neoplastic; Genes, bcl-2; Genes, p53; Humans; Models, Biological; Naphthoquinones; Radiation Tolerance; Radiation-Sensitizing Agents; Reactive Oxygen Species

The jadomycins are a series of natural products produced by Streptomyces venzuelae ISP5230 in response to ethanol shock. A unique structural feature of these angucyclines is the oxazolone ring, the formation of which is catalyzed by condensation of a biosynthetic aldehyde intermediate and an amino acid. The feeding of enantiomeric forms of alpha-amino acids indicates that the amino acid is incorporated by S. venezuelae ISP5230 without isomerization at the alpha-carbon. The characterization of the first two six-membered E-ring-containing jadomycins is reported. These precursor-directed biosynthesis studies indicate flexibility in the acceptor substrate specificity of the glycosyltransferase, JadS. Analysis of cytotoxicity data against two human breast cancer cell lines indicates that the nature of the substitution at the alpha-carbon, rather than the stereochemistry, influences biological activity.

Topics: Breast Neoplasms; Carbon; Catalysis; Cell Line, Tumor; Dose-Response Relationship, Drug; Drug Design; Ethanol; Humans; Isoleucine; Isoquinolines; Magnetic Resonance Spectroscopy; Naphthoquinones; Oxazolone; Stereoisomerism; Streptomyces

Shikonin, isolated from the plant Lithospermum erythrorhizon Sieb. Et Zucc, has been reported to induce apoptosis in several tumor cells. However, such effect of shikonin on human breast cancer cells has not been reported. Thus, in the present study, whether shikonin could induce MCF-7 human breast cancer cell apoptosis was investigated. The results showed that shikonin (2.5-80 microM) induced MCF-7 cell death in a time- and dose-dependent manner, as measured by MTT assay. The IC(50) of a 24 h, 48 h and 72 h time course for MCF-7 cells was 7.4+/-0.4, 6.3+/-0.6 and 3.9+/-0.5 microM, respectively. Cellular morphology observation showed that MCF-7 cells underwent marked apoptotic morphological changes upon treatment with 10 microM shikonin compared with the untreated control. Flow cytometric analysis of shikonin-treated MCF-7 cells showed that the ratio of the apoptotic DNA fragmentation increased in a dose-dependent manner. The present study demonstrated for the first time that the cytotoxic effect of shikonin on MCF-7 cells underwent apoptosis process.

Topics: Anti-Inflammatory Agents, Non-Steroidal; Apoptosis; Breast Neoplasms; Cell Proliferation; DNA Fragmentation; DNA, Neoplasm; Dose-Response Relationship, Drug; Female; Flow Cytometry; Humans; Naphthoquinones; Tumor Cells, Cultured

This study is the first to investigate the anticancer effect of plumbagin in human breast cancer cells. Plumbagin exhibited cell proliferation inhibition by inducing cells to undergo G2-M arrest and autophagic cell death. Blockade of the cell cycle was associated with increased p21/WAF1 expression and Chk2 activation, and reduced amounts of cyclin B1, cyclin A, Cdc2, and Cdc25C. Plumbagin also reduced Cdc2 function by increasing the association of p21/WAF1/Cdc2 complex and the levels of inactivated phospho-Cdc2 and phospho-Cdc25C by Chk2 activation. Plumbagin triggered autophagic cell death but not predominantly apoptosis. Pretreatment of cells with autophagy inhibitor bafilomycin suppressed plumbagin-mediated cell death. We also found that plumbagin inhibited survival signaling through the phosphatidylinositol 3-kinase/AKT signaling pathway by blocking the activation of AKT and downstream targets, including the mammalian target of rapamycin, forkhead transcription factors, and glycogen synthase kinase 3beta. Phosphorylation of both of mammalian target of rapamycin downstream targets, p70 ribosomal protein S6 kinase and 4E-BP1, was also diminished. Overexpression of AKT by AKT cDNA transfection decreased plumbagin-mediated autophagic cell death, whereas reduction of AKT expression by small interfering RNA potentiated the effect of plumbagin, supporting the inhibition of AKT being beneficial to autophagy. Furthermore, suppression of AKT by plumbagin enhanced the activation of Chk2, resulting in increased inactive phosphorylation of Cdc25C and Cdc2. Further investigation revealed that plumbagin inhibition of cell growth was also evident in a nude mouse model. Taken together, these results imply a critical role for AKT inhibition in plumbagin-induced G2-M arrest and autophagy of human breast cancer cells.

Topics: Animals; Antineoplastic Agents, Phytogenic; Apoptosis; Autophagy; Breast Neoplasms; Cell Division; Cell Growth Processes; Cell Line, Tumor; Female; G2 Phase; Humans; Mice; Mice, Inbred BALB C; Mice, Nude; Naphthoquinones; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Protein Kinases; Proto-Oncogene Proteins c-akt; RNA, Small Interfering; Sirolimus; TOR Serine-Threonine Kinases

Salvicine, a diterpenoid quinone compound, possesses potent in vitro and in vivo antitumor activity. Salvicine is a novel non-intercalative topoisomerase II poison. In this study salvicine induced evident DNA damage, which was further characterized as double-strand breaks mainly in MCF-7 human breast cancer cells. The degree of damage was highly correlated with growth inhibition of MCF-7. Using a PCR-stop assay we demonstrated that this damage was selective. Preferential damage occurred in the p2 promoter region, but not the 3'-end of the protooncogene c-myc. The expression of oncogenes, such as c-myc and c-jun, was additionally investigated. Salvicine induced a dose-dependent decrease in c-myc gene transcription, concomitant with an increase in c-jun expression. Furthermore, reverse-transcription PCR and Western blotting data revealed that salvicine failed to stimulate the mRNA and protein levels of p53 and its downstream targets p21 and bax. The phosphorylation degree of serine 15 of p53, which is thought to be an active form of p53 in response to cellular DNA damage, remained in a steady state. In view of these results, we propose that the downregulation of c-myc resulting from selective damage plays a role in apoptosis signaling. Moreover, salvicine-induced apoptosis in MCF-7 subsequent to DNA damage seems to be mediated through a p53-independent pathway.

Topics: Antineoplastic Agents; Apoptosis; Breast Neoplasms; Cell Division; DNA Damage; Gene Expression Regulation; Genes, myc; Humans; Naphthoquinones; Promoter Regions, Genetic; Proto-Oncogene Proteins c-jun; Reverse Transcriptase Polymerase Chain Reaction; Topoisomerase II Inhibitors; Tumor Cells, Cultured; Tumor Suppressor Protein p53

Several aziridinylbenzoquinone drugs have undergone clinical trials as potential antitumor drugs. These bioreductive compounds are designed to kill cells preferentially within the hypoxia tumor microenvironment. The bioreductive compound of bis-type naphthoquinone synthesized in our laboratory, 2-aziridin-1-yl-3-[(2-{2-[(3-aziridin-1-yl-1,4-dioxo-1,4-dihydronaphthalen-2-yl)thio]ethoxy}ethyl)thio]naphthoquinone (AZ-1), had the most potent death effect on the breast cancer cells BC-M1 in our previous screening. In the present study, we determined that the mechanism of the death effect of BC-M1 cells induced by AZ-1 was mediated by the apoptosis pathway.. We evaluated the cytotoxicity of AZ-1 and the anti-breast cancer drugs tamoxifen and paclitaxel to BC-M1 cells and MCF-7 cells by the MTT assay and measured the apoptosis phenomena by Hoechst 33258 staining for apoptotic bodies. We also quantified the sub-G1 peak area and the ratio of the CH2/CH3 peak area of the cell membrane in BC-M1 cells by flow cytometry and 1H-NMR spectra, respectively. The apoptosis-related protein expressions, including p53, p21, the RNA-relating protein T-cell restricted intracellular antigen-related protein, cyclin-dependent kinase 2 (cell cycle regulating kinase) and pro-caspase 3, were detected by western blot, and the caspase-3 enzyme activity was also quantified by an assay kit.. AZ-1 induced two of the breast cancer cell lines, with IC50 = 0.51 microM in BC-M1 cells and with IC50= 0.57 microM in MCF-7 cells, and showed less cytotoxicity to normal fibroblast cells (skin fibroblasts) with IC50= 5.6 microM. There was a 10-fold difference between two breast cancer cell lines and normal fibroblasts. Of the two anti-breast cancer drugs, tamoxifen showed IC50= 0.12 microM to BC-M1 cells and paclitaxel had much less sensitivity than AZ-1. The expression of p53 protein increased from 0.5 to 1.0 microM AZ-1 and decreased at 2.0 microM AZ-1. The p21 protein increased from 0.5 microM AZ-1, with the highest at 2 microM AZ-1. Regarding the AZ-1 compound-induced BC-M1 cells mediating the apoptosis pathway, the apoptotic body formation, the sub-G1 peak area, the ratio of CH2/CH3 of phospholipids in the cell membrane and the enzyme activity of caspase-3 were all in direct proportion with the dose-dependent increase of the concentration of AZ-1. The death effect-related proteins, including T-cell restricted intracellular antigen-related protein, cyclin-dependent kinase 2, and pro-caspase-3, all dose-dependently decreased with AZ-1 concentration.. The AZ-1-induced cell death of BC-M1 cells mediating the apoptosis pathway might be associated with p53 protein expression, and AZ-1 could have the chance to be a candidate drug for anti-breast cancer following more experimental evidence, such as animal models.

Topics: Antineoplastic Agents, Hormonal; Antineoplastic Agents, Phytogenic; Apoptosis; Aziridines; Blotting, Western; Breast Neoplasms; Female; Genes, p53; Humans; Naphthoquinones; Paclitaxel; Tamoxifen; Tumor Cells, Cultured; Tumor Suppressor Protein p53

Cdc25 phosphatases are important in cell cycle control and activate cyclin-dependent kinases (Cdk). Efforts are currently under way to synthesize specific small-molecule Cdc25 inhibitors that might have anticancer properties. NSC 95397, a protein tyrosine phosphatase antagonist from the National Cancer Institute library, was reported to be a potent Cdc25 inhibitor. We have synthesized two hydroxyl derivatives of NSC 95397, monohydroxyl-NSC 95397 and dihydroxyl-NSC 95397, which both have enhanced activity for inhibiting Cdc25s. The new analogues, especially dihydroxyl-NSC 95397, potently inhibited the growth of human hepatoma and breast cancer cells in vitro. They influenced two signaling pathways. The dual phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) was induced, likely due to inhibition of the ERK phosphatase activity in Hep 3B cell lysate but not the dual specificity ERK phosphatase MKP-1. They also inhibited Cdc25 enzymatic activities and induced tyrosine phosphorylation of the Cdc25 target Cdks. Addition of hydroxyl groups to the naphthoquinone ring thus enhanced the potency of NSC 95397. These two new compounds may be useful probes for the biological functions of Cdc25s and have the potential for disrupting the cell cycle of growing tumor cells.

Topics: Antineoplastic Agents; Biotinylation; Blotting, Western; Breast Neoplasms; Carcinoma, Hepatocellular; cdc25 Phosphatases; Cell Cycle Proteins; Cell Line, Tumor; Cell Proliferation; Cell-Free System; DNA; Dual Specificity Phosphatase 1; Flavonoids; Flow Cytometry; Humans; Immediate-Early Proteins; Immunoprecipitation; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Naphthoquinones; Phosphoprotein Phosphatases; Phosphorylation; Protein Phosphatase 1; Protein Tyrosine Phosphatases; Signal Transduction; Time Factors; Transfection; Tyrosine

Salvicine is a novel DNA topoisomerase II inhibitor with potent anticancer activity. In present study, the effect of salvicine against metastasis is evaluated using human breast carcinoma orthotopic metastasis model and its mechanism is further investigated both in animal and cellular levels.. The MDA-MB-435 orthotopic xenograft model was applied to detect the antimetastatic effect of salvicine. Potential target candidates were detected and analyzed by microarray technology. Candidates were verified and explored by reverse transcription-PCR and Western blot. Salvicine activities on stress fiber formation, invasion, and membrane translocation were further investigated by immunofluorescence, invasion, and ultracentrifugal assays.. Salvicine significantly reduced the lung metastatic foci of MDA-MB-435 orthotopic xenograft, without affecting primary tumor growth obviously. A comparison of gene expression profiles of primary tumors and lung metastatic focus between salvicine-treated and untreated groups using the CLOTECH Atlas human Cancer 1.2 cDNA microarray revealed that genes involved in tumor metastasis, particularly those closely related to cell adhesion and motility, were obviously down-regulated, including fibronectin, integrin alpha3, integrin beta3, integrin beta5, FAK, paxillin, and RhoC. Furthermore, salvicine significantly down-regulated RhoC at both mRNA and protein levels, greatly inhibited stress fiber formation and invasiveness of MDA-MB-435 cells, and markedly blocked translocation of both RhoA and RhoC from cytosol to membrane.. The unique antimetastatic action of salvicine, particularly its specific modulation of cell motility in vivo and in vitro, is closely related to Rho-dependent signaling pathway.

Topics: Animals; Blotting, Western; Breast Neoplasms; Cell Line, Tumor; Cell Membrane; Cytosol; Female; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Humans; Lung Neoplasms; Lysophospholipids; Mammary Neoplasms, Experimental; Mice; Mice, Nude; Naphthoquinones; Protein Transport; ras Proteins; Reverse Transcriptase Polymerase Chain Reaction; rho GTP-Binding Proteins; rhoA GTP-Binding Protein; rhoC GTP-Binding Protein; RNA, Messenger; Signal Transduction; Stress Fibers; Xenograft Model Antitumor Assays

Reactive oxygen species (ROS) are produced by all aerobic cells and have been implicated in the regulation of diverse cellular functions, including intracellular signaling, transcription activation, proliferation, and apoptosis. Salvicine, a novel diterpenoid quinone compound, demonstrates a broad spectrum of antitumor activities. Although salvicine is known to trap the DNA-topoisomerase II (Topo II) complex and induce DNA double-strand breaks (DSBs), its precise antitumor mechanisms remain to be clarified. In this study, we investigated whether salvicine altered the levels of ROS in breast cancer MCF-7 cells and whether these ROS contributed to the observed antitumoral activity. Our data revealed that salvicine stimulated intracellular ROS production and subsequently elicited notable DSBs. The addition of N-acetyl cysteine (NAC), an antioxidant, effectively attenuated the salvicine-induced ROS enhancement and subsequent DNA DSBs. Heat treatment reversed the accumulation of DNA DSBs, and the addition of NAC attenuated the Topo II-DNA cleavable complexes formation and the growth inhibition of salvicine-treated JN394top2-4 yeast cells, collectively indicating that Topo II is a target of the salvicine-induced ROS. On the other hand, when examining the impact of salvicine on DNA repair pathways, we unexpectedly observed that salvicine selectively down-regulated the catalytic subunit of DNA-dependent protein kinase (DNA-PK(CS)) protein levels and repressed DNA-PK kinase activity; both of these effects were attenuated by NAC pretreatment of MCF-7 cells. Finally and most importantly, NAC attenuated salvicine-induced apoptosis and cytotoxicity in MCF-7 cells. These results indicate that apart from its direct actions, salvicine generates ROS that modulate DNA damage and repair, contributing to the comprehensive biological consequences of salvicine treatment, such as DNA DSBs, apoptosis, and cytotoxicity in tumor cells. The finding of salvicine-induced ROS provides new evidence for the molecular mechanisms of this compound. Moreover, the effects of salvicine-induced ROS on Topo II and DNA-PK give new insights into the diverse biological activities of ROS.

Topics: Acetylcysteine; Apoptosis; Blotting, Western; Breast Neoplasms; Cell Line, Tumor; DNA; DNA Damage; DNA-Activated Protein Kinase; DNA-Binding Proteins; Enzyme Inhibitors; Humans; Naphthoquinones; Nuclear Proteins; Protein Serine-Threonine Kinases; Reactive Oxygen Species; Topoisomerase II Inhibitors

The aggressiveness of a tumor is partly attributed to its resistance to chemotherapeutic agent-induced apoptosis. Cysteine-rich 61 (Cyr61), from the CCN gene family, is a secreted and matrix-associated protein, which is involved in many cellular activities such as growth and differentiation. Here we established a cell model system to examine whether stable expression of Cyr61 in MCF-7 cells can confer resistance to apoptosis and identify possible participating mechanisms. We showed that stable cell lines overexpressing Cyr61 had acquired a remarkable resistance to apoptosis induced by paclitaxel, adriamycin, and beta-lapachone. Most interesting, gel shift and reporter assays showed that the Cyr61-overexpressing cells had significantly increased NF-kappaB activity compared with neo control cells. Blockage of NF-kappaB activity in Cyr61-expressing cells by transfecting with a dominant negative (DN)-IkappaB or with an NF-kappaB decoy rendered them more susceptible to anti-cancer drugs-induced apoptosis. In addition, several NF-kappaB-regulated anti-apoptotic genes were examined, and we found that only XIAP showed a significant 3-4-fold increase in mRNA and protein in Cyr61-overexpressing cells but not in neo control cells. Treatment with inhibitor of apoptosis protein (XIAP)-specific antisense, but not sense, oligonucleotides abolished the apoptosis resistance of the Cyr61-overexpressing cells. At the same time, transfection of these stable cells with DN-IkappaB to block NF-kappaB activity also effectively reduced the elevated XIAP level. Function-neutralizing antibodies to alpha(v)beta(3) and alpha(v)beta(5) could inhibit Cyr61-mediated NF-kappaB activation as well as XIAP expression. Taken together, our data suggested that Cyr61 plays an important role in resistance to chemotherapeutic agent-induced apoptosis in human breast cancer MCF-7 cells by a mechanism involving the activation of the integrins/NF-kappaB/XIAP signaling pathway.

Topics: Active Transport, Cell Nucleus; Antibiotics, Antineoplastic; Antineoplastic Agents, Phytogenic; Apoptosis; Blotting, Western; Breast Neoplasms; Cell Division; Cell Line, Tumor; Cell Nucleus; Cell Survival; Cysteine-Rich Protein 61; DNA; Doxorubicin; Flow Cytometry; Genes, Dominant; Genes, Reporter; Humans; Immediate-Early Proteins; Integrin alphaVbeta3; Integrins; Intercellular Signaling Peptides and Proteins; Microscopy, Fluorescence; Models, Biological; Naphthoquinones; NF-kappa B; Oligonucleotides, Antisense; Paclitaxel; Promoter Regions, Genetic; Proteins; Receptors, Vitronectin; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Signal Transduction; Time Factors; Transfection; Up-Regulation; X-Linked Inhibitor of Apoptosis Protein

We have investigated the antitumor functions and mechanisms of 1,2-naphthoquinone-2-thiosemicarbazone (NQTS) and its metal complexes (Cu(2+), Pd(2+), and Ni(2+)) against MCF-7 human breast cancer cells. The cells were dosed with these complexes at varying concentrations, and cell viability was measured by a sulforhodamine B (SRB) method. To study mechanisms of action, the complexes were incubated with topoisomerase II (topo II) and supercoiled DNA, linear DNA, nicked open DNA, and relaxed DNA were detected by agarose gel electrophoresis. The results revealed that these complexes are effective antitumor chemicals in inhibiting MCF-7 cell growth, with Ni-NQTS being the most effective among the complexes studied. Our data also indicated that Ni-NQTS is more effective than the commercial antitumor drug, etoposide, based on IC(50) values. The mechanistic study of action showed that metal complexes of NQTS, NQ, and NQTS can only stabilize the single-strand nicked DNA, but not double-strand breakage intermediates. In addition, metal derivatives of these ligands, but not the parent NQ and NQTS, exerted an antagonizing effect on topoisomerase II activity. In summary, chemicals with or without metal derivatives might possess different chemical-topoisomerase II-DNA interactions.

Topics: Antineoplastic Agents; Apoptosis; Breast Neoplasms; Cell Line, Tumor; DNA, Neoplasm; Dose-Response Relationship, Drug; Female; Humans; In Situ Nick-End Labeling; Indicators and Reagents; Metals; Naphthoquinones; Topoisomerase II Inhibitors

Diosquinone [1], a naphthoquinone epoxide previously isolated from the root bark of Diospyros mespiliformis (Hostch) and D. tricolor [Ebenaceae] is been assessed for cytotoxicity activity against ten cancer cell lines by standard NIH method. The ethno-pharmacological claim of this plant and the previously observed good antibacterial activity of this compound among the others isolated from this plant suggest its probable cytotoxicity activity. Diosquinone was observed to be very active against most of the cancer cell lines. It shows very good activity against all the cell lines tested with ED50 value ranging between 0.18 microg/ml. against Human Glioblastoma (U373) to 4.5 microg/ml. against Hormone dependent human prostrate cancer( LNCaP).

Topics: Antineoplastic Agents; Breast Neoplasms; Colonic Neoplasms; Diospyros; Drug Resistance, Multiple; Female; Fibrosarcoma; Humans; Lung Neoplasms; Male; Naphthoquinones; Nasopharyngeal Neoplasms; Neoplasms, Hormone-Dependent; Phytotherapy; Plant Extracts; Prostatic Neoplasms; Tumor Cells, Cultured

A convenient synthesis of the new enamine derivatives 2-(4-morpholinyl)-3-(3-methyl-2-butenyl)-1,4-naphthalenedione, 2-(1-piperidinyl)-3-(3-methyl-2-butenyl)-1,4-naphtalenedione and 2-(1-pyrrolidinyl)-3-(3-methyl-2-butenyl)-1,4-naphthalenedione was carried out from natural 2-hydroxy-3-(3-methyl-2-butenyl)-1,4-naphthalenedione (lapachol) and morpholine, piperidine and pyrrolidine. The structures of the products were established mainly by NMR analysis, including 2D experiments. Biological activities of these products were evaluated against Artemia salina, Aedes aegypti and cytotoxicity using A549 human breast cells.

Topics: Aedes; Amines; Animals; Antineoplastic Agents, Phytogenic; Artemia; Breast Neoplasms; Drug Evaluation, Preclinical; Female; Humans; Magnetic Resonance Spectroscopy; Naphthoquinones; Tumor Cells, Cultured

beta-Lapachone (beta-Lap) triggers apoptosis in a number of human breast and prostate cancer cell lines through a unique apoptotic pathway that is dependent upon NQO1, a two-electron reductase. Downstream signaling pathway(s) that initiate apoptosis following treatment with beta-Lap have not been elucidated. Since calpain activation was suspected in beta-Lap-mediated apoptosis, we examined alterations in Ca(2+) homeostasis using NQO1-expressing MCF-7 cells. beta-Lap-exposed MCF-7 cells exhibited an early increase in intracellular cytosolic Ca(2+), from endoplasmic reticulum Ca(2+) stores, comparable to thapsigargin exposures. 1,2-Bis-(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester, an intracellular Ca(2+) chelator, blocked early increases in Ca(2+) levels and inhibited beta-Lap-mediated mitochondrial membrane depolarization, intracellular ATP depletion, specific and unique substrate proteolysis, and apoptosis. The extracellular Ca(2+) chelator, EGTA, inhibited later apoptotic end points (observed >8 h, e.g. substrate proteolysis and DNA fragmentation), suggesting that later execution events were triggered by Ca(2+) influxes from the extracellular milieu. Collectively, these data suggest a critical, but not sole, role for Ca(2+) in the NQO1-dependent cell death pathway initiated by beta-Lap. Use of beta-Lap to trigger an apparently novel, calpain-like-mediated apoptotic cell death could be useful for breast and prostate cancer therapy.

Topics: 4-Nitroquinoline-1-oxide; Adenosine Triphosphate; Apoptosis; Blotting, Western; Breast Neoplasms; Calcium; Cell Death; Cell Division; Chelating Agents; Cytosol; DNA Fragmentation; Dose-Response Relationship, Drug; Egtazic Acid; Endoplasmic Reticulum; Female; Flow Cytometry; Humans; In Situ Nick-End Labeling; Male; Membrane Potentials; Microscopy, Confocal; Mitochondria; Models, Biological; Naphthoquinones; Prostatic Neoplasms; Quinolones; Signal Transduction; Time Factors; Tumor Cells, Cultured

beta-Lapachone activates a novel apoptotic response in a number of cell lines. We demonstrate that the enzyme NAD(P)H:quinone oxidoreductase (NQO1) substantially enhances the toxicity of beta-lapachone. NQO1 expression directly correlated with sensitivity to a 4-h pulse of beta-lapachone in a panel of breast cancer cell lines, and the NQO1 inhibitor, dicoumarol, significantly protected NQO1-expressing cells from all aspects of beta-lapachone toxicity. Stable transfection of the NQO1-deficient cell line, MDA-MB-468, with an NQO1 expression plasmid increased apoptotic responses and lethality after beta-lapachone exposure. Dicoumarol blocked both the apoptotic responses and lethality. Biochemical studies suggest that reduction of beta-lapachone by NQO1 leads to a futile cycling between the quinone and hydroquinone forms, with a concomitant loss of reduced NAD(P)H. In addition, the activation of a cysteine protease, which has characteristics consistent with the neutral calcium-dependent protease, calpain, is observed after beta-lapachone treatment. This is the first definitive elucidation of an intracellular target for beta-lapachone in tumor cells. NQO1 could be exploited for gene therapy, radiotherapy, and/or chemopreventive interventions, since the enzyme is elevated in a number of tumor types (i.e. breast and lung) and during neoplastic transformation.

Topics: Antibiotics, Antineoplastic; Apoptosis; Blotting, Western; Breast Neoplasms; Cell Division; Cytochrome Reductases; Cytochrome-B(5) Reductase; Dicumarol; Dose-Response Relationship, Drug; Drug Synergism; Enzyme Inhibitors; Flow Cytometry; Humans; Models, Biological; NAD; NADH, NADPH Oxidoreductases; NADPH-Ferrihemoprotein Reductase; Naphthoquinones; Proteins; Quinone Reductases; Transfection; Tumor Cells, Cultured; Tumor Suppressor Protein p53; Vitamin K

beta-Lapachone (beta-lap) effectively killed MCF-7 and T47D cell lines via apoptosis in a cell-cycle-independent manner. However, the mechanism by which this compound activated downstream proteolytic execution processes were studied. At low concentrations, beta-lap activated the caspase-mediated pathway, similar to the topoisomerase I poison, topotecan; apoptotic reactions caused by both agents at these doses were inhibited by zVAD-fmk. However at higher doses of beta-lap, a novel non-caspase-mediated "atypical" cleavage of PARP (i.e., an approximately 60-kDa cleavage fragment) was observed. Atypical PARP cleavage directly correlated with apoptosis in MCF-7 cells and was inhibited by the global cysteine protease inhibitors iodoacetamide and N-ethylmaleimide. This cleavage was insensitive to inhibitors of caspases, granzyme B, cathepsins B and L, trypsin, and chymotrypsin-like proteases. The protease responsible appears to be calcium-dependent and the concomitant cleavage of PARP and p53 was consistent with a beta-lap-mediated activation of calpain. beta-Lap exposure also stimulated the cleavage of lamin B, a putative caspase 6 substrate. Reexpression of procaspase-3 into caspase-3-null MCF-7 cells did not affect this atypical PARP proteolytic pathway. These findings demonstrate that beta-lap kills cells through the cell-cycle-independent activation of a noncaspase proteolytic pathway.

Topics: Antibiotics, Antineoplastic; Apoptosis; Breast Neoplasms; Cysteine Endopeptidases; Enzyme Activation; Female; Humans; Naphthoquinones; Tumor Cells, Cultured

Electrochemical methods have been widely used to monitor physiologically important molecules in biological systems. This report describes the first application of the scanning electrochemical microscope (SECM) to probe the redox activity of individual living cells. The possibilities of measuring the rate and investigating the pathway of transmembrane charge transfer are demonstrated. By this approach, significant differences are detected in the redox responses given by nonmotile, nontransformed human breast epithelial cells, breast cells with a high level of motility (engendered by overexpression of protein kinase Calpha), and highly metastatic breast cancer cells. SECM analysis of the three cell lines reveals reproducible differences with respect to the kinetics of charge transfer by several redox mediators.

Topics: Animals; Breast; Breast Neoplasms; Cattle; Cell Line; Cell Membrane; Cell Movement; Cells, Immobilized; Electrochemistry; Epithelial Cells; Female; Humans; Isoenzymes; Microscopy, Electron, Scanning; Naphthoquinones; Neoplasm Metastasis; Oxidation-Reduction; Protein Kinase C; Protein Kinase C-alpha; Transfection; Tumor Cells, Cultured; Vitamin K

Four naturally occurring quinones, mansonone-D (MD), mansonone-H (MH), thespone (TP) and thespesone (TPE), extracted from the heartwood of Thespesia populnea have been tested for their cytotoxic action by aerobic incubation with human breast adenocarcinoma (MCF-7) cells. Toxicity of the quinones follows the order MD > TP > MH approximately TPE. EPR spectrometric and Clark electrode oximetric studies indicate that redox cycling of these quinones produce superoxide anion radical (O2*-) and H2O2 on aerobic incubation with NADH:cytochrome c reductase. Generation of superoxide radical during enzymatic reduction of quinones, was confirmed by EPR spin trapping experiment using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as a spin trap. Cyclic voltammetric studies show reversible redox couples for MD and TP whereas TPE and MH show irreversible redox couple. The electrochemical results indicate that MH and TPE are more difficult to reduce than TP and MD.

Topics: Antineoplastic Agents, Phytogenic; Breast Neoplasms; Cell Survival; Electron Spin Resonance Spectroscopy; Female; Humans; Naphthoquinones; Oxidation-Reduction; Oxygen Consumption; Plant Extracts; Quinones; Structure-Activity Relationship; Superoxides; Tumor Cells, Cultured

Beta-lapachone (beta-lap) affects a number of enzymes in vitro, including type I topoisomerase (Topo I); however, its exact intracellular target(s) and mechanism of cell killing remain unknown. We compared the cytotoxic responses of MCF-7:WS8 (MCF-7) human breast cancer cells after 4-h pulses of beta-lap or camptothecin (CPT), a known Topo I poison. A direct correlation between loss of survival and apoptosis was seen after beta-lap treatment (LD50 = 2.5 microM). A concentration-dependent, transient sub-2 N preapoptotic cell population was observed at 4-8 h. Estrogen deprivation-induced synchronization and bromodeoxyuridine-labeling studies revealed an apoptotic exit point near the G1-S border. Apoptosis activated by beta-lap was closely correlated with cleavage of lamin B but not with increases in p53/p21 or decreases in bcl-2. Loss of hyperphosphorylated forms of the retinoblastoma protein was observed within 5 h, but cyclins A, B1, and E levels were unaltered for up to 72 h after 5 microM beta-lap. Topo I and Topo IIalpha levels decreased at > 24 h. Logarithmic-phase MCF-7 cells were not affected by < or = 1 microM beta-lap. In contrast, dramatic and irreversible G2-M arrest with no apoptosis was observed in MCF-7 cells treated with 1 microM CPT, monitored for 6-10 days posttreatment. MCF-7 cells treated with supralethal doses of CPT (5 microM) resulted in only approximately 20% apoptosis. No correlation between apoptosis and loss of survival was observed. MCF-7 cells exposed to > 5 microM CPT arrested at key cell cycle checkpoints (i.e., G1, S, and G2-M), with little or no movement for 6 days. Ten-fold increases in p53/p21 and 2-5-fold decreases in bcl-2, Topo I, Topo IIalpha, and cyclins A and B1, with no change in cyclin E, were observed. Temporal decreases in bcl-2 and cleavage of lamin B corresponded to the minimal apoptotic response observed. Beta-lap activated apoptosis without inducing p53/p21 or cell cycle arrest responses and killed MCF-7 cells solely by apoptosis. In contrast, concentration-dependent increases in nuclear p53/p21 and various cell cycle checkpoint arrests were seen in MCF-7 cells after CPT. Despite dramatic p53/p21 protein induction responses, CPT-treated MCF-7 cells showed low levels of apoptosis, possibly due to protective cell cycle checkpoints or the lack of specific CPT-activated apoptotic pathways in MCF-7 cells.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Breast Neoplasms; Camptothecin; Cell Cycle; Cell Cycle Proteins; Cell Survival; Cyclin-Dependent Kinase Inhibitor p21; Cyclins; DNA Topoisomerases, Type I; Dose-Response Relationship, Drug; Female; Humans; Lethal Dose 50; Naphthoquinones; Proto-Oncogene Proteins c-bcl-2; Reverse Transcriptase Inhibitors; Tumor Cells, Cultured; Tumor Suppressor Protein p53

Topics: Atovaquone; Bias; Breast Neoplasms; Drug Combinations; Estrogen Replacement Therapy; Female; Humans; Naphthoquinones; Proguanil

beta-Lapachone and certain of its derivatives directly bind and inhibit topoisomerase I (Topo I) DNA unwinding activity and form DNA-Topo I complexes, which are not resolvable by SDS-K+ assays. We show that beta-lapachone can induce apoptosis in certain cells, such as in human promyelocytic leukemia (HL-60) and human prostate cancer (DU-145, PC-3, and LNCaP) cells, as also described by Li et al. (Cancer Res., 55: 0000-0000, 1995). Characteristic 180-200-bp oligonucleosome DNA laddering and fragmented DNA-containing apoptotic cells via flow cytometry and morphological examinations were observed in 4 h in HL-60 cells after a 4-h, > or = 0.5 microM beta-lapachone exposure. HL-60 cells treated with camptothecin or topotecan resulted in greater apoptotic DNA laddering and apoptotic cell populations than comparable equitoxic concentrations of beta-lapachone, although beta-lapachone was a more effective Topo I inhibitor. beta-Lapachone treatment (4 h, 1-5 microM) resulted in a block at G0/G1, with decreases in S and G2/M phases and increases in apoptotic cell populations over time in HL-60 and three separate human prostate cancer (DU-145, PC-3, and LNCaP) cells. Similar treatments with topotecan or camptothecin (4 h, 1-5 microM) resulted in blockage of cells in S and apoptosis. Thus, beta-lapachone causes a block in G0/G1 of the cell cycle and induces apoptosis in cells before, or at early times during, DNA synthesis. These events are p53 independent, since PC-3 and HL-60 cells are null cells, LNCaP are wild-type, and DU-145 contain mutant p53, yet all undergo apoptosis after beta-lapachone treatment. Interestingly, beta-lapachone treatment of p53 wild type-containing prostate cancer cells (i.e., LNCaP) did not result in the induction of nuclear levels of p53 protein, as did camptothecin-treated cells. Like other Topo I inhibitors, beta-lapachone may induce apoptosis by locking Topo I onto DNA, blocking replication fork movement, and inducing apoptosis in a p53-independent fashion. beta-Lapachone and its derivatives, as well as other Topo I inhibitors, have potential clinical utility alone against human leukemia and prostate cancers.

Topics: Apoptosis; Breast Neoplasms; Camptothecin; Cell Division; Dimethyl Sulfoxide; Drug Screening Assays, Antitumor; G1 Phase; Humans; Leukemia, Promyelocytic, Acute; Male; Naphthoquinones; Prostatic Neoplasms; Resting Phase, Cell Cycle; Time Factors; Topoisomerase I Inhibitors; Tumor Cells, Cultured; Tumor Stem Cell Assay

The inhibition of phosphatidylinositol-3-kinase (PtdIns-3-kinase), protein kinase C and c-Src protein tyrosine kinase by a series of halogenated naphthoquinones and quinoline quinones related to the plant-derived naphthoquinones juglone and methyljuglone, which inhibit protein kinase C, has been investigated. Some of the compounds inhibited PtdIns-3-kinase at micromolar concentrations and below. PtdIns-3-kinase inhibition was time dependent and could be prevented by endogenous thiol. The compounds were only weak inhibitors of PtdIns-4-kinase. Some of the compounds inhibited protein kinase C, but c-Src protein tyrosine kinase was only weakly inhibited. In intact cells, PtdIns-3-kinase was only partly inhibited by concentrations of the halogenated quinones that inhibited cell growth. Some halogenated quinones showed in vivo antitumor activity without accompanying toxicity, while methyljuglone was without in vivo antitumor activity. Halogenated quinones may have multiple biochemical effects in the cell that could contribute to their cytotoxic and antitumor effects. Inhibition of PtdIns-3-kinase by the halogenated quinones may provide a lead for the development of more potent and specific inhibitors.

Topics: Breast Neoplasms; Colonic Neoplasms; CSK Tyrosine-Protein Kinase; Female; Humans; Naphthoquinones; Phosphatidylinositol 3-Kinases; Phosphotransferases (Alcohol Group Acceptor); Protein Kinase C; Protein-Tyrosine Kinases; src-Family Kinases; Tumor Cells, Cultured; Tumor Stem Cell Assay