naphthoquinones and Carcinoma

Topics: Adenoma; Animals; Carcinogens; Carcinoma; Drug Evaluation, Preclinical; Lethal Dose 50; Liver Neoplasms; Male; Mice; Naphthoquinones

Chemical modification of the thiol group on protein tyrosine phosphatase (PTP) 1B triggers an activation of epidermal growth factor receptor (EGFR) signaling that is mimicked by environmental electrophiles through S-modification of PTP1B. While activation of PTP1B/EGFR by a single exposure to an electrophile has been established, the effects of combined exposure to electrophiles are unknown. Here, we examined the activation of EGFR signaling by combined exposure to ambient electrophiles in human epithelial carcinoma A431 cells. Simultaneous exposure to 1,2- and 1,4-naphthoquinone (NQ) augmented the S-modification of endogenous and recombinant human PTP1B (hPTP1B). Combined exposure of hPTP1B or A431 cells to 1,2- and 1,4-NQ escalated the inactivation of PTP compared with individual exposure. Phosphorylation of EGFR and its downstream kinase extracellular signal-regulated kinase (ERK) 1/2 by 1,2-NQ exposure was facilitated by simultaneous exposure to 1,2-NQ with 10 µM 1,4-NQ. An EGFR inhibitor diminished the phosphorylation of ERK1/2, indicating that ERK was phosphorylated following EGFR activation by the NQ cocktail. The combined exposure to NQs also accelerated cell death in A431 cells compared with each NQ alone. While no EGFR/ERK activation was seen following 1,4-benzoquinone (BQ) treatment, exposure to 1,4-NQ in the presence of 1,4-BQ increased 1,4-NQ-mediated activation of EGFR. This suggests that the enhancement of 1,4-NQ-dependent EGFR activation by 1,4-BQ is caused by a different mechanism than 1,2-NQ with 1,4-NQ. These results suggest that combined exposure to ambient electrophiles, even at low concentrations, can induce stronger activation of redox signaling than individual exposure. Our findings indicate that combining different electrophiles may produce unexpected effects.

Topics: Carcinoma; Cell Death; Cell Line, Tumor; ErbB Receptors; Humans; Mitogen-Activated Protein Kinase 3; Naphthoquinones; Oxidation-Reduction; Phosphorylation; Protein Tyrosine Phosphatase, Non-Receptor Type 1; Signal Transduction

The imidazolium compound YM155, first discovered as a potent inhibitor of Survivin, effectively kills many carcinomas in preclinical models. However, the upstream signaling mechanism triggered by YM155 remains unclear. Here we studied early signaling responses in vitro in prostate and renal cancer cell lines in a dose-dependent manner. We found that YM155 rapidly activates the retinoblastoma protein, correlating with the loss of expression of all three Cyclin Ds. Using Western blot, various selective chemical inhibitors and q-PCR, we show that YM155-mediated decrease in protein levels of Cyclin Ds, Survivin and Mcl-1 is independent of transcription or proteasomal control mechanisms. Moreover, we provide the first evidence that YM155 changes the phosphorylation status of known mTOR-target proteins involved in translational control, namely ribosomal protein S6 (rS6) and 4E-BP1. Our data support that YM155 achieves this by blocking mTORC1 via the phosphorylation of Raptor at S792 through activated AMPKα (T172). Furthermore, we also used a polysome profile, supporting that YM155 markedly suppresses cap-dependent translation of mRNAs which include Survivin, Cyclin D1 and Mcl-1. We provide the first evidence that YM155 functions as a potent activator of AMPKα, a robust suppressor of mTORC1 and an attenuator of global protein synthesis.

Topics: Adaptor Proteins, Signal Transducing; AMP-Activated Protein Kinase Kinases; Apoptosis; Carcinoma; Cell Cycle Proteins; Cell Line, Tumor; Cell Proliferation; Cyclin D; Gene Expression Regulation, Neoplastic; Humans; Imidazoles; Male; Mechanistic Target of Rapamycin Complex 1; Naphthoquinones; Prostate; Prostatic Neoplasms; Protein Kinases; Signal Transduction; Survivin

Shikonin, a natural small agent, has shown inhibitory effect in many kinds of cells, which increases intracellular reactive oxygen species (ROS) level and causes mitochondrial injury. In this study, shikonin showed good inhibitory effect on nasopharyngeal carcinoma CNE-2Z cells in vivo and vitro. The results presented here revealed that ROS levels increased markly after shikonin treated. The electron microscopy displays the change in ultrastructure of CNE-2Z cells after treatment for shikonin, which indicated that shikonin induced necroptosis. Shikonin-induced cell death was inhibited by a necroptosis inhibitor, necrostatin-1 (Nec-1), while the activity was unaffected by the caspase inhibitor z-VAD-fmk. Furthermore, we have demonstrated that the activation of receptor-interacting kinase (RIP) led to necroptosis. Meanwhile, shikonin also significantly inhibited tumor growth in a CNE-2Z xenograft mouse model. Taken together, shikonin induced CNE-2Z cells death by producing ROS as a necroptosis inducer. It could serve as a new therapeutic agent for treating CNE-2Z cells.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Apoptosis; Carcinoma; Cell Line, Tumor; Heterografts; Humans; Mice; Mice, Nude; Naphthoquinones; Nasopharyngeal Carcinoma; Nasopharyngeal Neoplasms; Necrosis; Reactive Oxygen Species

Nasopharyngeal carcinoma (NPC) is a peculiar Epstein Barr virus (EBV)-associated malignancy that is prevalent in South-East Asia. Peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (PIN1) isomerizes specific phosphorylated amino acid residues, which makes it an important regulator in cell survival and apoptosis. In this study, we investigated the contribution made by PIN1 in NPC tumorigenesis and PIN1's potential role as a therapeutic target.. The expression of PIN1 was examined in a panel of NPC cell lines, xenografts and primary tumors. The functional roles of PIN1 in NPC cells were elucidated by the knockdown and overexpression of PIN1 in in vitro and in vivo nude mice models by siRNA and lenti-viral transfection, respectively. The antitumor effects of the PIN1 inhibitor Juglone in NPC cells were also evaluated.. We revealed the consistent overexpression of PIN1 in almost all EBV-associated NPC cell lines, xenografts and primary tumors. PIN1 suppression was capable of inhibiting cyclin D1 expression and activating caspase-3 in NPC cells. It positively regulated NPC cell proliferation, colony formation and anchorage-independent growth. The inhibition of PIN1 suppressed tumor growth in vitro and in vivo.. This study demonstrates the oncogenic role of PIN1 in NPC tumorigenesis, and shows that its overexpression can enhance tumor cell growth via the upregulation of cyclinD1. Our findings inform the development of novel treatments targeting PIN1 for NPC patients.

Topics: Animals; Carcinoma; Caspase 3; Cell Line, Tumor; Cell Proliferation; Cyclin D1; Female; HeLa Cells; Herpesvirus 4, Human; Humans; Immunohistochemistry; In Vitro Techniques; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Middle Aged; Naphthoquinones; Nasopharyngeal Carcinoma; Nasopharyngeal Neoplasms; NIMA-Interacting Peptidylprolyl Isomerase; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction

This study aims to explore the apoptotic function of shikonin on the papillary thyroid cancer cells and the related mechanism. The papillary thyroid cancer cell lines K1 and W3 and thyroid follicular epithelial cells NTHY-ORI 3-1 were treated with different concentrations of shikonin. Cell proliferation was tested. Morphological changes of the apoptotic cells were observed by Hoechst 33342 staining. The apoptosis rate of the papillary thyroid cancer cells was measured with flow cytometry. Changes of the cell cycle were explored. The mitochondrial membrane potential changes were analyzed after JC-1 staining. Bcl-2 family proteins and caspase-3 expression with shikonin treatment was analyzed by real-time fluorescence polymerase chain reaction (PCR). Cell proliferation of K1 and W3 was inhibited by shikonin, and the inhibition was dose-time dependent. Papillary thyroid carcinoma cells treated by shikonin had no obvious cell cycle arrest but were observed with the higher apoptosis rate and the typical apoptotic morphological changes of the cell nucleus. JC-1 staining showed that shikonin reduced the mitochondrial membrane potential of papillary thyroid carcinoma cells. Real-time PCR results showed that shikonin significantly increased Bax and caspase-3 expression and upregulated Bcl-2 expression in a dose-dependent manner in papillary thyroid carcinoma cells. However, the NTHY-ORI 3-1 was almost not affected by shikonin treatment. Shikonin can inhibit K1 and W3 cell proliferation in a dose- and time-dependent manner, enhance Bax levels, reduce anti-apoptotic protein Bcl-2 levels, result in decreasing mitochondrial membrane potential and activating caspase-3 enzyme, and finally lead to apoptosis.

Topics: Anti-Inflammatory Agents, Non-Steroidal; Apoptosis; Carcinoma; Carcinoma, Papillary; Cell Line, Tumor; Cell Proliferation; Flow Cytometry; Humans; Membrane Potential, Mitochondrial; Naphthoquinones; Real-Time Polymerase Chain Reaction; Thyroid Cancer, Papillary; Thyroid Neoplasms

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

Induction of apoptosis in tumor cells has become the major focus of anti-tumor therapeutics development. Juglone, a major chemical constituent of Juglans mandshurica Maxim, possesses several bioactivities, including anti-tumor. In the present study, HeLa cells were incubated with juglone at various concentrations. The proliferation inhibition of juglone on HeLa cells was tested by the MTT assay. Occurrence of apoptosis was detected by Hoechst 33258 staining, flow cytometry, and transmission electron microscopy. The expression of apoptotic-related proteins was examined by Western blot. The results showed that juglone inhibits the growth of HeLa cells in dose-dependent manner. Topical morphological changes of apoptotic body formation after juglone treatment were observed. The percentages of early apoptosis of Annexin V-FITC were 5.23%, 7.95%, 10.69%, and 20.92% with the concentrations of juglone (12.5, 25, 50, and 100 µmol/L), respectively. After cells were treated with juglone at the different dose for 24 h, the expression of Bcl-2 was significantly down-regulated and the expression of Bax was significantly up-regulated compared with the control. These events paralleled with activation of caspase-9, -8, -3, and PARP cleavage. The results suggest that juglone may be effective for the treatment of HeLa cells.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Apoptosis Regulatory Proteins; Blotting, Western; Carcinoma; Caspases; Cell Proliferation; Down-Regulation; Enzyme Activation; Female; HeLa Cells; Humans; Microscopy, Electron, Transmission; Naphthoquinones; Neoplasm Proteins; Osmolar Concentration; Poly (ADP-Ribose) Polymerase-1; Poly(ADP-ribose) Polymerases; Proteolysis; Up-Regulation; Uterine Cervical Neoplasms

A series of mansonone F (MF) derivatives were designed and synthesized. These compounds were found to be strong inhibitors for topoisomerases, with much more significant inhibition for topoisomerase II rather than topoisomerase I. The best inhibitor showed 20 times stronger anti-topoisomerase II activity than a positive control Etoposide. The cytotoxic activity of these MF derivatives was evaluated against human cancer cell lines CNE-2 and Glc-82, which showed that these compounds were potent antitumor agents. The structure-activity relationships (SARs) study revealed that o-quinone group and pyran ring are important for their cytotoxic activity.

Topics: Adenocarcinoma; Adenocarcinoma of Lung; Antigens, Neoplasm; Antineoplastic Agents; Carcinoma; Cell Line, Tumor; Cell Survival; DNA; DNA Topoisomerases, Type I; DNA Topoisomerases, Type II; DNA-Binding Proteins; Drug Screening Assays, Antitumor; Etoposide; Humans; Inhibitory Concentration 50; Lung Neoplasms; Naphthoquinones; Nasopharyngeal Carcinoma; Nasopharyngeal Neoplasms; Plasmids; Pyrans; Quinones; Sesquiterpenes; Structure-Activity Relationship; Telomerase; Topoisomerase Inhibitors

A series of new natural tanshinone-like oxoheterocyclic-fused ortho-quinone derivatives were synthesized from readily available benzofuranol and N-substituted dienes via IBX oxidation-cycloaddition-aromatization procedure. The regiospecific Diels-Alder cycloaddition reactions of N-dienes were achieved efficiently with a variety of dienophiles. It is found that the amide moiety in the molecular could be preserved or eliminated by control of the aromatization conditions. Selected oxoheterocyclic-fused ortho-quinones as well as several thioheterocyclic-fused ortho-quinones we obtained before were evaluated for their cytotoxicities on different cancer cell lines and the Structure-Activity Relationship (SAR) was discussed.

Topics: Adenocarcinoma; Antineoplastic Agents; Carcinoma; Cell Line, Tumor; Cell Proliferation; Furans; Humans; Lung Neoplasms; Models, Molecular; Molecular Structure; Naphthoquinones; Nasopharyngeal Neoplasms; Stereoisomerism; Structure-Activity Relationship

Pancreatic cancer is one of the most resistant malignancies. Several studies have indicated that plumbagin isolated from Plumbago zeylanica possesses anticancer activity. However, its antitumor effects against pancreatic cancer have not been explored.. We investigated the effect of plumbagin on the growth of human pancreatic carcinoma cells and its possible underlying mechanisms.. Plumbagin inhibited the growth of Panc-1 and Bxpc-3 cells in a dose-dependent and time-dependent manner. Liu's staining and transmission electron microscopy demonstrated morphological changes resembling apoptosis in Panc-1 cells treated with plumbagin. The degree of apoptosis was assessed by measuring the proportions of sub-G(1), annexin V+/propidium iodide-, and terminal- deoxynucleotidyl-transferase-mediated-nick-end labeling (TUNEL)+ cells, and a significant increment in apoptotic cells was observed. Exposure to plumbagin caused the upregulation of Bax, a rapid decline in mitochondrial transmembrane potential, apoptosis-inducing factor overexpression in cytosol, and the cleavage of procaspase-9 and poly ADP-ribose polymerase. Activation of caspase-3, but not caspase-8, was evidenced by fluorometric substrate assay. Pretreatment with caspase inhibitors did not block plumbagin-induced apoptosis. Alternatively, it is possible that plumbagin downregulated phosphoinositide 3-kinase activity through a negative feedback mechanism. In an orthotopic pancreatic tumor model, plumbagin markedly inhibited the growth of Panc-1 xenografts without any significant effect on leukocyte counts or body weight.. Plumbagin may induce apoptosis in human pancreatic cancer cells primarily through the mitochondria-related pathway followed by both caspase-dependent and caspase-independent cascades. It indicates that plumbagin can be potentially developed as a novel therapeutic agent against pancreatic cancer.

Topics: Animals; Antineoplastic Agents; Apoptosis; bcl-2-Associated X Protein; Carcinoma; Caspases; Cell Line, Tumor; Cell Proliferation; Humans; Membrane Potential, Mitochondrial; Mice; Mice, Nude; Naphthoquinones; Pancreatic Neoplasms; Plumbaginaceae; Xenograft Model Antitumor Assays

Telomere repeat binding factor 2 (TRF2) has been increasingly recognized to be involved in DNA damage response and telomere maintenance. Our previous report found that salvicine (SAL), a novel topoisomerase II poison, elicited DNA double-strand breaks and telomere erosion in separate experimental systems. However, it remains to be clarified whether they share a common response to these two events and in particular whether TRF2 is involved in this process. In this study, we found that SAL concurrently induced DNA double-strand breaks, telomeric DNA damage, and telomere erosion in lung carcinoma A549 cells. It was unexpected to find that SAL led to disruption of TRF2, independently of either its transcription or proteasome-mediated degradation. By overexpressing the full-length trf2 gene and transfecting TRF2 small interfering RNAs, we showed that TRF2 protein protected both telomeric and genomic DNA from the SAL-elicited events. It is noteworthy that although both the Ataxia-telangiectasia-mutated (ATM) and the ATM- and Rad3-related (ATR) kinases responded to the SAL-induced DNA damages, only ATR was essential for the telomere erosion. The study also showed that the activated ATR augmented the SAL-triggered TRF2 disruption, whereas TRF2 reduction in turn enhanced ATR function. All of these findings suggest the emerging significance of TRF2 protecting both telomeric DNA and genomic DNA on the one hand and reveal the mutual modulation between ATR and TRF2 in sensing DNA damage signaling during cancer development on the other hand.

Topics: Ataxia Telangiectasia Mutated Proteins; Carcinoma; Cell Cycle Proteins; Cell Line, Tumor; Cell Proliferation; Comet Assay; DNA Breaks, Double-Stranded; DNA-Binding Proteins; Humans; Lung Neoplasms; Naphthoquinones; Nuclear Proteins; Protein Serine-Threonine Kinases; RNA, Small Interfering; Statistics as Topic; Telomere; Telomeric Repeat Binding Protein 2; Transfection; Tumor Suppressor Proteins

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

Various accumulating evidence suggests that survivin, a member of the inhibitor of apoptosis (IAP) family, plays an important role in drug resistance and cancer cell survival in many types of cancer, including hormone-refractory prostate cancer (HRPC). Here, we characterized YM155, a novel small-molecule survivin suppressant, using a survivin gene promoter activity assay. YM155 suppressed expression of survivin and induced apoptosis in PC-3 and PPC-1 human HRPC cell lines at 10 nmol/L. In contrast, YM155 up to 100 nmol/L showed little effect on expression levels of other IAP- or Bcl-2-related proteins. In a s.c. xenografted PC-3 tumor model in mice, 3-day continuous infusions of YM155 at 3 to 10 mg/kg induced massive tumor regression accompanied by suppression of intratumoral survivin. YM155 also completely inhibited the growth of orthotopically xenografted PC-3 tumors. No significant decreases in body weight were observed in mice treated with YM155 during the experimental period. Pharmacokinetic analyses indicated that YM155 is highly distributed to tumors and at concentrations approximately 20-fold higher than those in plasma. Our findings represent the first attempt to show tumor regression and suppression of survivin in p53-deficient human HRPC cells by a single small molecular compound treatment. Further extensive investigation of YM155 in many types of cancer, including HRPC, seems to be worthwhile to develop this novel therapeutic approach.

Topics: Animals; Antineoplastic Agents; Antineoplastic Agents, Hormonal; Carcinoma; CHO Cells; Cricetinae; Cricetulus; Drug Evaluation, Preclinical; Drug Resistance, Neoplasm; HeLa Cells; Humans; Imidazoles; Inhibitor of Apoptosis Proteins; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Microtubule-Associated Proteins; Models, Biological; Naphthoquinones; Neoplasm Proteins; Prostatic Neoplasms; Remission Induction; Survivin; Treatment Failure; Tumor Burden; Tumor Cells, Cultured; Xenograft Model Antitumor Assays

The objective of the present study was to investigate the effect of beta-lapachone, a quinone obtained from the bark of the lapacho tree (Tabebuia avellanedae), on the cell growth and apoptosis in human lung carcinoma cell line A549. Exposure of A549 cells to beta-lapachone resulted in growth inhibition and induction of apoptosis in a time- and dose-dependent manner as measured by hemocytometer counts, fluorescence microscopy and flow cytometry analysis. This increase in apoptosis was associated with a decrease in Bcl-2 and expression, an increase of Bax, and an activation of caspase-3 and caspase-9. beta-lapachone treatment markedly inhibited the activity of telomerase in a dose-dependent fashion. Additionally, the levels of human telomerase RNA (hTR) and c-myc expression were progressively down-regulated by beta-lapachone treatment. Taken together, these findings provide important new insights into the possible molecular mechanisms of the anti-cancer activity of beta-lapachone.

Topics: Apoptosis; Carcinoma; Cell Proliferation; Dose-Response Relationship, Drug; Flow Cytometry; Humans; Lung Neoplasms; Naphthoquinones; Plant Extracts; Reverse Transcriptase Inhibitors; Tabebuia; Telomerase; Tumor Cells, Cultured

There are two fundamental forms of cell death: apoptosis and necrosis. Molecular studies of cell death thus far favor a model in which apoptosis and necrosis share very few molecular regulators. It appears that apoptotic processes triggered by a variety of stimuli converge on the activation of a member of the caspase family, such as caspase 3, which leads to the execution of apoptosis. It has been suggested that blocking of caspase activation in an apoptotic process may divert cell death to a necrotic demise, suggesting that apoptosis and necrosis may share some upstream events. Activation of caspase is preceded by the release of mitochondrial cytochrome C.. We first studied cell death induced by beta-lapachone by MTT and colony-formation assay. To determine whether the cell death induced by beta-lapachone occurs through necrosis or apoptosis, we used the PI staining procedure to determine the sub-G1 fraction and the Annexin-V staining for externalization of phophatidylserine. We next compared the release of mitochondrial cytochrome C in apoptosis and necrosis. Mitochondrial cytochrome C was determined by Western blot analysis. To investigate changes in mitochondria that resulted in cytochrome C release, the mitochondrial membrane potential (delta psi) was analyzed by the accumulation of rhodamine 123, a membrane-permeant cationic fluorescent dye. The activation of caspase in apoptosis and necrosis were measured by using a profluorescent substrate for caspase-like proteases, PhiPhiLuxG6D2.. beta-lapachone induced cell death in a spectrum of human carcinoma cells, including nonproliferating cells. It induced apoptosis in human ovary, colon, and lung cancer cells, and necrotic cell death in four human breast cancer cell lines. Mitochondrial cytochrome C release was found in both apoptosis and necrosis. This cytochrome C release occurred shortly after beta-lapachone treatment when cells were fully viable by trypan blue exclusion and MTT assay, suggesting that cytochrome C release is an early event in beta-lapachone induced apoptosis as well as necrosis. The mitochondrial cytochrome C release induced by beta-lapachone is associated with a decrease in mitochondrial transmembrane potential (delta psi). There was activation of caspase 3 in apoptotic cell death, but not in necrotic cell death. This lack of activation of CPP 32 in human breast cancer cells is consistent with the necrotic cell death induced by beta-lapachone as determined by absence of sub-G1 fraction, externalization of phosphatidylserine.. beta-lapachone induces either apoptotic or necrotic cell death in a variety of human carcinoma cells including ovary, colon, lung, prostate, and breast, suggesting a wide spectrum of anti-cancer activity in vitro. Both apoptotic and necrotic cell death induced by beta-lapachone are preceded by a rapid release of cytochrome C, followed by the activation of caspase 3 in apoptotic cell death but not in necrotic cell death. Our results suggest that beta-lapachone is a potential anti-cancer drug acting on the mitochondrial cytochrome C-caspase pathway, and that cytochrome C is involved in the early phase of necrosis.

Topics: Antibiotics, Antineoplastic; Apoptosis; Carcinoma; Caspase 3; Caspases; Cell Death; Cytochrome c Group; Dose-Response Relationship, Drug; Enzyme Activation; Female; Humans; Male; Membrane Potentials; Mitochondria; Naphthoquinones; Necrosis; Tumor Cells, Cultured

An antibiotic, identical with naphthomycin, was isolated from a soil Streptomyces. The antibiotic displayed significant therapeutic activity by ip administration against murine tumors: Ehrlich carcinoma and IMC carcinoma implanted ip. The maximum increase of life-span was more than 169% in Ehrlich carcinoma, and 128% in IMC carcinoma. The antibiotic exhibited a potent cytotoxicity against murine leukemic cells: P388, L1210, and L5178Y. IC50 was 0.4-1.3 microgram/ml in culture. The activity of naphthomycin was reversed by SH compounds: 2-mercaptoethanol, dithiothreitol, and glutathione. DNA and RNA syntheses were more markedly inhibited by naphthomycin than protein synthesis in L5178Y cells. Approximately 50% inhibition of nucleic acid syntheses was observed at an antibiotic concentration of 2 micrograms/ml. Naphthomycin blocked alkaline phosphodiesterase obtained from L5178Y cells: IC50 was ca. 7.6 micrograms/ml. The antibiotic neither caused metaphase arrest nor prevented tubulin polymerization. The results suggest that the mechanism of cytotoxicity of naphthomycin is the inhibition of various SH enzymes, particularly those involved in nucleic acid biosynthesis. The mode of action is unique in the ansamycin group of antibiotics.

Topics: Animals; Antibiotics, Antineoplastic; Carcinoma; Carcinoma, Ehrlich Tumor; Cell Survival; Cells, Cultured; Female; Lethal Dose 50; Leukemia, Experimental; Mice; Mitosis; Naphthoquinones; Neoplasms, Experimental; Soil Microbiology; Streptomyces

Topics: Adenocarcinoma; Animals; Anthraquinones; Antineoplastic Agents; Carcinoma; Carcinoma 256, Walker; Cell Line; Leukemia L1210; Mouth Neoplasms; Naphthoquinones; Quinones; Sarcoma 180; Structure-Activity Relationship

Topics: Amnion; Animals; Carcinoma; Cattle; Cell Line; Culture Techniques; Fibroblasts; Haplorhini; HeLa Cells; Humans; Kidney; Laryngeal Neoplasms; Lung; Naphthoquinones; Tritium

Topics: Animals; Antifibrinolytic Agents; Ascites; Carcinoma; Glycolysis; Lymphoma; Metabolism; Mice; Naphthoquinones; Neoplasms, Experimental; Vitamin K; Vitamin K 1; Vitamins

Topics: Bronchi; Bronchial Neoplasms; Carcinoma; Humans; Naphthoquinones; Vitamin K