naphthoquinones and Colonic-Neoplasms

Topics: Autophagy; Carcinogenesis; Cell Line, Tumor; Cell Proliferation; Colonic Neoplasms; Colorectal Neoplasms; Gene Expression Regulation, Neoplastic; GTP-Binding Protein beta Subunits; Humans; MicroRNAs; Naphthoquinones

Indomethacin [IND] is reported to treat colon cancer. However, continuous exposure to IND causes gastric ulceration, an adverse side effect in humans. This study implies the therapeutic effect of IND and juglone [JUG] against colon carcinogenesis, without gastric ulceration - an adverse side effect of IND.. Adult male Balb/C mice were divided into six groups randomly: control, AOM/DSS-induced, IND-treated, JUG-treated, IND + JUG-treated and drug-control. Levels of serum markers, haematoxylin & eosin staining to observe tissue architecture, toluidine blue staining to detect mast cells expression, Masson's trichrome and sirius-red staining were used to detect the collagen deposition. RT-PCR and western blot analysis were carried out to detect inflammation and apoptosis.. IND + JUG effectively decreased the levels of serum markers: CEA, AFP, LDH, AST and ALT. Although, IND restored colonic architecture by regulating the accumulation of mast cell and collagen content, it causes gastric ulceration. To address this adverse effect of IND, JUG was given along with IND and was shown to alleviate IND-induced gastric ulceration. AOM/DSS induced animals showed increased expression of inflammatory molecules - TNFα, NFκB and Cox-2, apoptosis regulator - Bcl-2 and decreased expression of pro-apoptotic molecules - Bad, Bax and caspase3; whereas, IND and JUG treated groups showed decreased inflammatory expression with increased expression of pro-apoptotic molecules.. IND and JUG reduce the inflammatory activity and induce apoptotic cell death, while JUG effectively prevents IND induced gastric ulceration. These findings establish that a combination of IND + JUG may serve as a promising treatment regimen for colon cancer.

Topics: Animals; Apoptosis; Azoxymethane; Carcinogenesis; Cell Count; Cell Line, Tumor; Collagen; Colonic Neoplasms; Dextran Sulfate; Indomethacin; Inflammation; Male; Mast Cells; Mice, Inbred BALB C; Naphthoquinones

Shikonin, a naphthoquinone compound extracted from the root of Lithospermum erythrorhizon, has been extensively studied for its antitumor activity. However, the systematic pathways involved in Shikonin intervention in human colon cancer has not yet clearly defined.. This study was to evaluate the cytotoxic effects of Shikonin in colon cancer, as well as investigate the potential biomarkers from a global perspective and the possible antitumor mechanisms involved.. In this work, cell viability, cell cycle and cell apoptosis in human colon cancer cells were assessed to evaluate the antitumor activity of Shikonin. Transcriptomics and metabolomics were integrated to provide the perturbed pathways and explore the potential mechanisms. The crucial proteins and genes involved were further validated by immunohistochemistry and real-time quantitative PCR.. Shikonin revealed a remarkable antitumor potency in colon cancer. Cell cycle was significantly arrested at the S phase as well as apoptosis was induced in SW480 cell line. Furthermore, a total of 1642 differentially expressed genes and 40 metabolites were detected after Shikonin intervention. The integrated analysis suggested that the antitumor effect was mainly attributed to purine metabolism, arginine biosynthesis, pyrimidine metabolism, urea cycle and metabolism of amino acids. The up-regulated expression of proteins vital for arginine biosynthesis was subsequently validated by immunohistochemistry in xenograft mice. Notably, supplemental dNTPs and arginine could significantly reverse the cytotoxic effect induced by Shikonin and the genes participating in purine metabolism and arginine biosynthesis were further determined by RT-qPCR.. Our findings provide a systematic perspective in the therapeutic effect of Shikonin which might lay a foundation for further research on Shikonin in colon cancer.

Topics: Animals; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Cell Survival; Colonic Neoplasms; Humans; Lithospermum; Metabolomics; Mice; Naphthoquinones; Plant Roots; Xenograft Model Antitumor Assays

Colorectal cancer (CRC) is the third most common fatal cancer. Indomethacin, a nonsteroidal anti-inflammatory drug, is known to reduce the occurrence of CRC. This study evaluated the potential anticolon cancer effects of juglone (5-hydroxy-1,4-naphthoquinone) in combination with indomethacin. Human colon adenocarcinoma cells (HT29) were subjected to treatment with indomethacin, juglone, and a combination of both. Morphological analysis, cell cycle regulation, and dual staining using acridine orange and ethidium bromide in control and treated cells revealed the apoptotic potential of these compounds. Bcl2 and inflammatory molecules (tumor necrosis factor-α, nuclear factor kappa B, and Cox-2) were found to be decreased with a concomitant increase in the expression of proapoptotic molecules (Bad, Bax, cytochrome c, and PUMA) as a result of the molecular regulation of Wnt, Notch, and peroxisome proliferator-activated receptor-γ signaling. Treatment with juglone was not as effective as with indomethacin; however, a combination of both was shown to be more effective, suggesting that juglone may be considered for therapeutic intervention of colon cancer.

Topics: Anti-Inflammatory Agents, Non-Steroidal; Antineoplastic Agents; Apoptosis; Apoptosis Regulatory Proteins; Cell Cycle Checkpoints; Cell Survival; Colonic Neoplasms; Drug Synergism; HT29 Cells; Humans; Indomethacin; Inflammation Mediators; Inhibitory Concentration 50; Naphthoquinones; PPAR gamma; Proto-Oncogene Proteins c-bcl-2; Receptors, Notch; Signal Transduction; Wnt Signaling Pathway

Topics: Anti-Bacterial Agents; Ascomycota; Biosynthetic Pathways; Cell Proliferation; Colonic Neoplasms; Genome, Fungal; Gram-Positive Bacteria; HCT116 Cells; Humans; Naphthoquinones; Secondary Metabolism

The efficacy of chemotherapeutic agents for colon cancer treatment is limited by multidrug resistance (MDR) and insufficient intracellular release of the administered nanomedicine. To overcome these limitations, we constructed a pH/ROS cascade-responsive and self-accelerating drug release nanoparticle system (PLP-NPs) for the treatment of multidrug-resistant colon cancer. The PLP-NPs comprised a reactive oxygen species (ROS)-sensitive polymeric paclitaxel (PTX) prodrug (DEX-TK-PTX), a pH-sensitive poly(l-histidine) (PHis), and beta-lapachone (Lapa), a ROS-generating agent. We found that PLP-NPs could accumulate in tumor tissue through enhancement of the permeability and retention (EPR) effect, and were subsequently internalized by cancer cells via the endocytic pathway. Within the acidic endo-lysosomal environment, PHis protonation facilitated the escape of the PLP-NPs from the lysosome and release of Lapa. The released Lapa generated a large amount of ROS, consumed ATP, and downregulated P-glycoprotein (P-gp) production through the activity of NQO1, an enzyme that is specifically overexpressed in tumor cells. In addition, the generated ROS promoted the release of PTX from DEX-TK-PTX to kill cancer cells, while ATP depletion inhibited P-gp-mediated MDR.

Topics: Animals; Cell Line, Tumor; Cell Survival; Colonic Neoplasms; Dextrans; Drug Carriers; Drug Delivery Systems; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Histidine; Humans; Hydrogen-Ion Concentration; Mice; Nanoparticles; Naphthoquinones; Paclitaxel; Prodrugs; Reactive Oxygen Species; Xenograft Model Antitumor Assays

Colorectal cancer (CRC) is a common malignancy occurring in the digestive system. Despite progress in surgery and therapy options, CRC is still a considerable cause of cancer mortality worldwide. In this study, a colon cancer patient-derived xenograft model was established to evaluate the antitumor activity of Shikonin. The protective effect underlying Shikonin was determined through assessing serum levels of liver enzymes (ALT, AST) and kidney functions (BuN, Scr) in PDX mice. Proteomics and metabolomics profiles were integrated to provide a systematic perspective in dynamic changes of proteins and global endogenous metabolites as well as their perturbed pathways. A total of 456 differently expressed proteins (DEPs), 32 differently expressed metabolites (DEMs) in tumor tissue, and 20 DEMs in mice serum were identified. The perturbation of arginine biosynthesis, purine metabolism, and biosynthesis of amino acids may mainly account for therapeutic mechanism of Shikonin. Furthermore, the expression of mRNAs participating in arginine biosynthesis (CPS1, OTC, Arg1) and do novo purine synthesis (GART, PAICS, ATIC) were validated through RT-qPCR. Our study provides new insights into the drug therapeutic strategies and a better understanding of antitumor mechanisms that might be valuable for further studies on Shikonin in the clinical treatment of colorectal cancer.

Topics: Alanine Transaminase; Animals; Antineoplastic Agents; Aspartate Aminotransferases; Blood Urea Nitrogen; Cell Cycle Checkpoints; Cell Proliferation; Colonic Neoplasms; Creatinine; Female; Humans; Metabolomics; Mice; Mice, Nude; Naphthoquinones; Neoplasm Proteins; Proteomics; Xenograft Model Antitumor Assays

Colon cancer is the second most common deadliest malignancy in the world and better understanding of its underlying mechanisms is needed to improve clinical management. Natural plant extracts are gaining attention in the development of new therapeutic strategies against various cancer types. Shikonin is a naturally extracted naphthoquinone pigment with effects against cancer, including colon cancer.. In this study, we conducted a series of in vitro experiments to show the effects of Shikonin on colon cancer cell apoptosis. A colon cancer cell line with overexpression of peroxiredoxin V (PrxV) was constructed and the relationship of PrxV expression with Shikonin-induced cell apoptosis was investigated.. Shikonin induced colon cancer cell apoptosis via regulation of mammalian target of rapamycin signaling. Shikonin-induced cell apoptosis was abrogated by overexpression of PrxV.. According to the results obtained in this study, targeting PrxV may provide new insight for the successful management of colon cancer by inducing cell apoptosis.

Topics: Anti-Inflammatory Agents, Non-Steroidal; Apoptosis; Biomarkers, Tumor; Cell Movement; Cell Proliferation; Colonic Neoplasms; Gene Expression Regulation, Neoplastic; Humans; Naphthoquinones; Peroxiredoxins; Tumor Cells, Cultured

Peroxiredoxin (Prx) V has been known as an antioxidant enzyme which scavenges intracellular reactive oxygen species (ROS). Also, Prx V has been shown to mediate cell apoptosis in various cancers. However, the mechanism of Prx V-induced apoptosis in colon cancer cells remains unknown. Thus, in this study we analyzed the effects of Prx V in β-lapachone-induced apoptosis in SW480 human colon cancer cells.. β-lapachone-induced apoptosis was analyzed by the MTT assay, western blotting, fluorescence microscopy, Annexin V staining and flow cytometry.. Overexpression of Prx V, significantly decreased β-lapachone-induced cellular apoptosis and Prx V silencing increased β-lapachone-induced cellular apoptosis via modulating ROS scavenging activity compared to mock SW480 cells. In addition, to further explore the mechanism of Prx V regulated β-lapachone-induced SW480 cells apoptosis, the Wnt/β-catenin signaling was studied. The Wnt/ β-catenin signaling pathway was found to be induced by β-lapachone.. Prx V regulates SW480 cell apoptosis via scavenging ROS cellular levels and mediating the Wnt/β-catenin signaling pathway, which was induced by β-lapachone.

Topics: Apoptosis; Cell Line, Tumor; Colon; Colonic Neoplasms; Humans; Naphthoquinones; Peroxiredoxins; Reactive Oxygen Species; Wnt Signaling Pathway

NSC 95397, a quinone-based small molecule compound, has been identified as an inhibitor for dual-specificity phosphatases, including mitogen-activated protein kinase phosphatase-1 (MKP-1). MKP-1 is known to inactivate mitogen-activated protein kinases by dephosphorylating both of their threonine and tyrosine residues. Moreover, owing to their participation in tumorigenesis and drug resistance in colon cancer cells, MKP-1 is an attractive therapeutic target for colon cancer treatment. We therefore investigated the inhibitory activity of NSC 95397 against three colon cancer cell lines including SW480, SW620, and DLD-1, and their underlying mechanisms. The results demonstrated that NSC 95397 reduced cell viability and anchorage-independent growth of all the three colon cancer cell lines through inhibited proliferation and induced apoptosis via regulating cell-cycle-related proteins, including p21, cyclin-dependent kinases, and caspases. Besides, by using mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) inhibitor U0126, we provided mechanistic evidence that the antineoplastic effects of NSC 95397 were achieved via inhibiting MKP-1 activity followed by ERK1/2 phosphorylation. Conclusively, our results indicated that NSC 95397 might serve as an effective therapeutic intervention for colon cancer through regulating MKP-1 and ERK1/2 pathway.

Topics: Apoptosis; Biomarkers; Caspase 3; Cell Cycle Proteins; Cell Line, Tumor; Cell Proliferation; Cell Survival; Colonic Neoplasms; Dual-Specificity Phosphatases; Humans; MAP Kinase Signaling System; Naphthoquinones; Tumor Stem Cell Assay

Topics: Calcium; Cell Death; Colonic Neoplasms; Cytosol; HCT116 Cells; Humans; Imidazoles; Indoles; MAP Kinase Kinase 4; Mitochondria; Multiprotein Complexes; Naphthoquinones; Nuclear Pore Complex Proteins; Reactive Oxygen Species; Receptor-Interacting Protein Serine-Threonine Kinases; RNA-Binding Proteins; RNA, Small Interfering; Signal Transduction

The present study was designed to assess the expression of microRNA-542-3p (miR-542-3p) in human colon cancer and investigate the possible molecular mechanisms underlying the effect of miR-542-3p on the growth and invasion of colon cancer cells. We found that miR-542-3p expression was downregulated in colon cancer patient tissues, compared with that observed in the control group. Silencing of miR‑542-3p expression significantly promoted cell viability and inhibited apoptosis. In addition, overexpression of miR-542-3p significantly reduced cell viability and promoted apoptosis in colon cancer cells. Meanwhile, silencing of miR-542-3p expression significantly suppressed PI3K and p-AKT and survivin protein expression, while overexpression of miR-542-3p significantly induced PI3K and p-AKT and survivin protein expression in colon cancer cells. PI3K inhibitor (LY294002) or survivin inhibitor (YM155) suppressed PI3K/AKT/survivin signaling and increased the anticancer effects of miR-542-3p on the apoptosis in colon cancer. The present study demonstrated that upregulation of miR-542-3p inhibited the growth and invasion of colon cancer cells through PI3K/AKT/survivin signaling, highlighting a novel therapeutic approach for the treatment of colon cancer.

Topics: Apoptosis; Cell Line, Tumor; Cell Proliferation; Chromones; Colonic Neoplasms; Female; Gene Expression Regulation, Neoplastic; Humans; Imidazoles; Inhibitor of Apoptosis Proteins; Male; MicroRNAs; Morpholines; Naphthoquinones; Neoplasm Invasiveness; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Signal Transduction; Survivin; Up-Regulation

Lawsone (LS) a colored napthoquinone compound obtained from the plant Lawsonia inermis L. (Lythraceae) is known for its usefulness of being a precursor for synthesis of some anticancer compounds. Literatures support potent anticancer activity of napthoquinone derivatives in human colon cancer, present study evaluates the effect and mechanism of LS on chemical induced colon cancerous rats and human colon cancer DLD-1 cells, the study was supported by endoscopy, histological and immunohistochemistry analysis. KAD rats were subjected to colon cancer mediated by Azoxymethane (AOM) injections followed Dextran sodium sulfate (DSS) orally in drinking water. After endoscopic confirmation the rats were given LS (200mg/ml) orally for 8 weeks. Presence of aberrant foci, types of tumors and the proliferative effect on tumor lesions was studied by macroscopic, histological and immunohistochemical analysis. To establish the mechanism, human colon DLD-1 cancer cells were exposed to LS and its effect on proliferation were studied. LS reduced aberrant crypt without affecting tumor pathology. Histological study of colon suggested decrease in numbers of adenomas and lesions. Immunohistochemistry confirmed the antiproliferative activity in adenocarcinomas without affecting the cells of normal colon mucosa. Results on human DLD-1 cells showed LS delayed progression of cell cycle by decreasing expression of cyclin B1 as well as cdk1 by inactivating NF-κB without inducing apoptosis. The study concluded role of LS in suppressing cell proliferation of colon tumors. The suppressive activity on DLD-1 cells was not by apoptosis but by decreased NF-κB activity resulting in suppression of expression levels of cyclin B1 and cdk1.

Topics: Adenocarcinoma; Animals; Antineoplastic Agents, Phytogenic; Azo Compounds; Carcinogens; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Colonic Neoplasms; Dextran Sulfate; Endoscopy; Humans; Intestinal Mucosa; Naphthoquinones; NF-kappa B; Rats; Signal Transduction

Shikonin is a kind of naphthoquinone compound found mainly in Lithospermum erythrorhizon Sieb,et Zucc. Previous studies have shown that Shikonin has anti-tumor, anti-inflammatory and extensive pharmacological effects. According to new studies, Shikonin could also modulate the immune system function, but the effect to NK (nature killer) cells is yet unknown.. To investigate the effect and mechanism of Shikonin on NK cells proliferation and cytotoxicity to colon cancer cell line (Caco-2).. The proliferation and cytotoxicity of NK cells cultured with Shikonin were detected with CCK-8 assay. The expressions of perforin, GranB and IFN-γ were examined with FCM. The content of TNF-alpha was disclosed with ELISA kit. p-ERK1/2 and p-Akt expression of NK cells were detected with western blot.. With CCK-8 assay, it is found that Shikonin could significantly enhance NK cells proliferation and cytotoxicity to colon cancer cells. With FCM assay, it is found that Shikonin could improve the expression of perforin and GranB in a dose-dependent manner. Shikonin had no effect on TNF-alpha and IFN-γ expression. In mechanism, the study shows that Shikonin could enhance the expression of p-ERK1/2 and p-Akt.. Shikonin enhances NK cells proliferation and cytotoxicity via the improvement of perforin, GranB, p-ERK1/2 and p-Akt expression.

Topics: Caco-2 Cells; Cell Proliferation; Colonic Neoplasms; Humans; Immunity, Cellular; Killer Cells, Natural; MAP Kinase Signaling System; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Naphthoquinones; Proto-Oncogene Proteins c-akt

Cisplatin-based therapy is one of the most important chemotherapy treatments for cancers. However, its efficacy is greatly limited by drug resistance and undesirable side effects. Therefore, it is of great importance to develop effective chemosensitization agents to cisplatin. In the present study, we demonstrated the strategy to use shikonin, a natural product from the root of Lithospermum erythrorhizon, as a synergistic agent of cisplatin and elucidated their action mechanisms. The combination of shikonin and cisplatin exhibited synergistic anticancer efficacy and achieved greater selectivity between cancer cells and normal cells. By inducing intracellular oxidative stress, shikonin potentiated cisplatin-induced DNA damage, followed by increased activation of mitochondrial pathway. In addition, inhibition of ROS reversed the apoptosis induced by shikonin and cisplatin, and recovered the depletion of mitochondrial membrane potential, which revealed the vital role of ROS in the synergism. Moreover, HCT116 xenograft tumor growth in nude mice was more effectively inhibited by combined treatment with shikonin and cisplatin. Our findings suggest that the strategy to apply shikonin as a synergistic agent to cisplatin could be a highly efficient way to achieve anticancer synergism by inducing intracellular oxidative stress. Shikonin may be a promising candidate as a chemosensitizer to cisplatin-based therapy for cancer treatments.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Cell Line, Tumor; Cisplatin; Colonic Neoplasms; Drug Synergism; Drugs, Chinese Herbal; Female; HT29 Cells; Humans; Mice; Mice, Inbred BALB C; Mice, Nude; Naphthoquinones; Reactive Oxygen Species; Treatment Outcome

Survivin has a known beneficial role in the survival of both cancer cells and normal cells. Therapies targeting survivin have been proposed as an alternative treatment modality for various tumors; however, finding the proper indication for this toxic therapy is critical for reducing unavoidable side effects. We recently observed that high survivin expression in CD133(+) cells is related to chemoresistance in Caco-2 colon cancer cells. However, the effect of survivin-targeted therapy on CD133(+) colon cancer is unknown. In this study, we investigated the roles of CD133 and survivin expression in colon cancer biology in vitro and comparatively analyzed the anticancer effects of survivin inhibitor on CD133(+) cells (ctrl-siRNA group) and small interfering RNA (siRNA)-induced CD133(-) cells (CD133-siRNA group) obtained from a single colon cancer cell line. CD133 knockdown via siRNA transfection did not change the tumorigenicity of cells, although in vitro survivin expression levels in CD133(+) cells were higher than those in siRNA-induced CD133(-) cells. The transfection procedure seemed to induce survivin expression. Notably, a significant number of CD133(-) cells (33.8%) was found in the cell colonies of the CD133-siRNA group. In the cell proliferation assay after treatment, YM155 and a combination of YM155 and 5-fluorouracil (5-FU) proved to be far more effective than 5-FU alone. A significantly increased level of apoptosis was observed with increasing doses of YM155 in all groups. However, significant differences in therapeutic effect and apoptosis among the mock, ctrl-siRNA, and CD133-siRNA groups were not detected. Survivin inhibitor is an effective treatment modality for colon cancer; however, the role of CD133 and the use of survivin expression as a biomarker for this targeted therapy must be verified.

Topics: Antineoplastic Agents; Apoptosis; Caco-2 Cells; Colonic Neoplasms; Dose-Response Relationship, Drug; Humans; Imidazoles; Inhibitor of Apoptosis Proteins; Naphthoquinones; Survivin; Treatment Outcome

Anticancer activity of diospyrin and its derivatives (1-5) was evaluated against thirteen human cell lines. Compared to diospyrin (1), the acetylamine derivative (4) exhibited increase in cytotoxicity, particularly in HT-29 colon cancer cells, showing GI50 values of 33.90 and 1.96 μM, respectively. Also, enhanced toxicity was observed when cells, pre-treated with compound 4, were exposed to radiation. In vivo assessment of 4 was undertaken on tumour-bearing Nod-Scid mice treated at 4 mg/kg/day. Significant reduction in relative tumour volume (~86-91 %) was observed during the 12th-37th days after drug treatment. Increased caspase-3 activity and DNA ladder formation was observed in HT-29 cells after treatment with 4, suggesting induction of apoptotic death after drug treatment. Moreover, flow cytometric determination of Annexin V- FITC positive and PI negative cells demonstrated 17.4, 26.4, and 27.9 % of early apoptosis, respectively, upon treatment with 5, 10 and 25 μM of 4. HT-29 cells after treatment with 4 (1-25 μM) revealed ~2.5- 3- folds generation of ROS. Furthermore, concentration dependent decrease of mitochondrial trans-membrane potential (∆ψm), and expression of Bcl-2/Bax and other marker proteins suggested involvement of mitochondrial pathway of cell death. Overall, our results demonstrated the underlying cell-death mechanism of the plant-derived naphthoquinonoid (4), and established it as a prospective chemotherapeutic 'lead' molecule against colon cancer.

Topics: Animals; Antineoplastic Agents, Phytogenic; Caspase 3; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cell Survival; Colonic Neoplasms; DNA Fragmentation; Humans; Membrane Potential, Mitochondrial; Mice, Inbred NOD; Mice, SCID; Naphthoquinones; Tumor Burden; Xenograft Model Antitumor Assays

β-lapachone (β-lap), an. quinone oxidoreductase 1 (NQO1) targeting antitumor drug candidate in phase II clinical trials, is metabolically eliminated via NQO1 mediated quinone reduction and subsequent UDP-glucuronosyltransferases (UGTs) catalyzed glucuronidation. This study intends to explore the inner link between the cellular glucuronidation and pharmacokinetics of β-lap and its apoptotic effect in human colon cancer cells. HT29 cells S9 fractions exhibited high glucuronidation activity towards β-lap, which can be inhibited by UGT1A9 competitive inhibitor propofol. UGT1A siRNA treated HT29 cells S9 fractions displayed an apparent low glucuronidation activity. Intracellular accumulation of β-lap in HCT116 cells was much higher than that in HT29 cells, correlated with the absence of UGT1A in HCT116 cells. The cytotoxic and apoptotic effect of β-lap in HT29 cells were much lower than that in HCT116 cells; moreover, β-lap triggered activation of SIRT1-FOXO1 apoptotic pathway was observed in HCT116 cells but not in HT29 cells. Pretreatment of HT29 cells with UGT1A siRNA or propofol significantly decreased β-lap's cytotoxic and apoptotic effects, due to the repression of glucuronidation and the resultant intracellular accumulation. In conclusion, UGT1A is an important determinant, via switching NQO1-triggered redox cycle to metabolic elimination, in the intracellular accumulation of β-lap and thereafter its cytotoxicity in human colon cancer cells. Together with our previous works, we propose that UGTs determined cellular pharmacokinetics is an important determinant in the apoptotic effects of NQO1 targeting substrates serving as chemotherapeutic drugs.

Topics: Antineoplastic Agents; Apoptosis; Colonic Neoplasms; Drug Resistance, Neoplasm; Forkhead Box Protein O1; Forkhead Transcription Factors; Glucuronic Acid; Glucuronosyltransferase; HCT116 Cells; HT29 Cells; Humans; Intracellular Space; Naphthoquinones; Reactive Oxygen Species; Signal Transduction; Sirtuin 1

A series of ferrocene and (arene)ruthenium(II) complexes attached to the naturally occurring anticancer naphthoquinones plumbagin and juglone was tested for efficacy against various cancer cell lines and for alterations in the mode of action. The plumbagin ferrocene and (p-cymene)Ru(II) conjugates 1c and 2a overcame the multi-drug drug resistance of KB-V1/Vbl cervix carcinoma cells and showed IC50 (72 h) values around 1 μM in growth inhibition assays using 3-(4,5-dimethyl-2-yl)-2,5-diphenyltetrazolium bromide (MTT). They were further investigated for their influence on the cell cycle of KB-V1/Vbl and HCT-116 colon carcinoma cells, on the generation of reactive oxygen species (ROS) by the latter cell line, for their substrate character for the P-glycoprotein drug eflux pump via the calcein-AM efflux assays, and for DNA affinity by the electrophoretic mobility shift assay (EMSA). The derivatives 1c and 2a increased the number of dead cancer cells (sub-G0/G1 fraction) in a dose- and time-dependent manner. ROS levels were significantly increased upon treatment with 1c and 2a. These compounds also showed a greater affinity to linear DNA than plumbagin. While plumbagin did not affect calcein-AM transport by P-glycoprotein the derivatives 1c and 2a exhibited a 50% or 80% inhibition of the P-glycoprotein-mediated calcein-AM efflux relative to the clinically established sensitizer verapamil.

Topics: Antineoplastic Agents, Phytogenic; ATP Binding Cassette Transporter, Subfamily B; Cell Cycle; Cell Line, Tumor; Colonic Neoplasms; Coordination Complexes; Cymenes; DNA; Female; Ferrous Compounds; Humans; Metallocenes; Monoterpenes; Naphthoquinones; Ruthenium; Uterine Cervical Neoplasms

Despite increased use of early detection methods and more aggressive treatment strategies, the worldwide incidence of colorectal cancer is still on the rise. Consequently, it remains urgent to identify novel agents with enhanced efficacy in prevention and/or therapeutic protocols. Our studies focused on the use of Plumbagin, a natural phytochemical that showed promising results against other tumor types, to determine its effectiveness in blocking the proliferation and survival of colon cancer cells in experimental protocols mimicking the environment in primary tumors (attached culture conditions) and in circulating tumor cells (unattached conditions). Under both experimental settings, exposure of HCT116 cells to Plumbagin concentrations in the low micromolar range resulted in cell cycle arrest at the G1 phase, apoptosis via the mitochondrial cell death pathway, and increased production of reactive oxygen species. The cell cycle effects were more noticeable in attached cells, whereas the induction of cell death was more evident in unattached cells. These effects were consistent with the nature and the magnitude of the alterations induced by Plumbagin on the expression levels of a set of proteins known to play key roles in the regulation of cell cycle dynamics, apoptosis mechanisms and cell proliferation. In light of its previously reported lack of toxicity on normal colon cells and the striking anti-survival effect on colon cancer cells observed in our study, Plumbagin should be considered a promising drug for the treatment of colon cancer.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Cell Cycle Checkpoints; Cell Proliferation; Cell Survival; Colonic Neoplasms; HCT116 Cells; Humans; Mitochondria; Naphthoquinones; Reactive Oxygen Species

Here we report that activation of AMP-activated protein kinase (AMPK) mediates plumbagin-induced apoptosis and growth inhibition in both primary cultured human colon cancer cells and cell lines. Knocking-down of AMPKα by the target shRNA significantly inhibits plumbagin-induced cytotoxicity in cultured colon cancer cells, while forced activation of AMPK by introducing a constitutively active AMPK (CA-AMPK), or by the AMPK activator, inhibits HT-29 colon cancer cell growth. Our Western-blots and immunoprecipitation (IP) results demonstrate that plumbagin induces AMPK/Apoptosis signal regulating kinase 1 (ASK1)/TNF receptor-associated factor 2 (TRAF2) association to activate pro-apoptotic c-Jun N-terminal kinases (JNK)-p53 signal axis. Further, after plumbagin treatment, activated AMPK directly phosphorylates Raptor to inhibit mTOR complex 1 (mTORC1) activation and Bcl-2 expression in colon cancer cells. Finally, we found that exogenously-added short-chain ceramide (C6) enhances plumbagin-induced AMPK activation and facilitates cell apoptosis and growth inhibition. Our results suggest that AMPK might be the key mediator of plumbagin's anti-tumor activity.

Topics: AMP-Activated Protein Kinases; Antineoplastic Agents, Phytogenic; Apoptosis; Cell Line, Tumor; Cell Proliferation; Colonic Neoplasms; Gene Expression Regulation, Neoplastic; HT29 Cells; Humans; Naphthoquinones; Phosphorylation; Primary Cell Culture; Reactive Oxygen Species; Signal Transduction

Plumbagin, a quinonoid found in the plants of the Plumbaginaceae, possesses medicinal properties. In this study we investigated the anti-proliferative and apoptotic activity of plumbagin by using two human colonic cancer cell lines, HT29 and HCT15. IC50 of Plumbagin for HCT15 and HT29 cells (22.5 µM and 62.5 µM, respectively) were significantly different. To study the response of cancer cells during treatment strategies, cells were treated with two different concentrations, 15 µM, 30 µM for HCT15 and 50 µM, 75 µM for HT29 cells. Though activation of NFκB, Caspases-3, elevated levels of TNF-α, cytosolic Cytochrome C were seen in both HCT15 cells HT29 treated with plumbagin, aberrant apoptosis with decreased level of pEGFR, pAkt, pGsk-3β, PCNA and Cyclin D1was observed only in 15 µM and 30 µM plumbagin treated HCT15 and 75 µM plumbagin treated HT29 cells. This suggests that plumbagin induces apoptosis in both HCT15 cells and HT29 treated, whereas, proliferation was inhibited only in 15 µM and 30 µM plumbagin treated HCT15 and 75 µM plumbagin treated HT29 cells, but not in 50 µM plumbagin treated HT29 cells. Expression of COX-2 was decreased in 75 µM plumbagin treated HT29 cells when compared to 50 µM plumbagin treated HT29 cells, whereas HCT15 cells lack COX. Hence the observed resistance to induction of apoptosis in 50 µM plumbagin treated HT29 cells are attributed to the expression of COX-2. In conclusion, plumbagin induces apoptosis in colonic cancer cells through TNF-α mediated pathway depending on expression of COX-2 expression.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Cell Cycle; Cell Line, Tumor; Colonic Neoplasms; Comet Assay; Cyclooxygenase 2; Cyclooxygenase Inhibitors; Flow Cytometry; Gene Expression Regulation, Neoplastic; Humans; Inhibitory Concentration 50; Naphthoquinones; Reverse Transcriptase Polymerase Chain Reaction; RNA, Small Interfering; Tetrazolium Salts; Thiazoles

Benzonaphthofurandione has been considered as an important class of naturally occurring and synthetic compounds having a variety of biological functions. In this study, we evaluated the antitumor effects of 3-[2-(dimethylamino)isopropoxy]-1-hydroxybenzo[b]naphtho[2,3-d]furan-6,11-dione (8e), a novel benzonaphthofurandione derivative, on the growth of colorectal cancer HCT 116 cells both in vitro culture and an in vivo animal model. Compound 8e exhibited the potential growth inhibition of the colon cancer cells in a concentration-dependent manner. The anti-proliferative activity of 8e was also associated with the induction of cell cycle arrest in the G(0)/G(1) phase. The 8e-induced cell cycle arrest was well correlated with the suppression of cyclin-dependent kinase 2 (CDK2), CDK4, cyclin D1, cyclin E, c-Myc, and phosphorylated retinoblastoma protein (pRb). The tumor growth in xenograft nude mice bearing HCT 116 cells by compound 8e (10mg/kg) also significantly inhibited without any overt toxicity. In addition, the down-regulation of epidermal growth factor receptor (EGFR), Akt, and mTOR signalings were associated with the anti-proliferative activity of compound 8e in colon cancer cells. Taken together, these findings suggested that cell cycle arrest and modulation of cell signal transduction pathways might be the plausible mechanisms of actions for the anti-proliferative activity of 8e, and thus 8e might be used as an effective chemotherapeutic agent in human colon cancer.

Topics: Animals; Antineoplastic Agents; Benzofurans; Cell Line, Tumor; Colonic Neoplasms; Cyclin D1; Cyclin E; Cyclin-Dependent Kinase 2; Cyclin-Dependent Kinase 4; Down-Regulation; ErbB Receptors; G1 Phase; Humans; Mice; Mice, Nude; Naphthoquinones; Proto-Oncogene Proteins c-myc; Resting Phase, Cell Cycle; Retinoblastoma Protein; Signal Transduction; TOR Serine-Threonine Kinases; Transplantation, Heterologous

Organotellurides are newly described redox-catalyst molecules with original pro-oxidative properties. We have investigated the in vitro and in vivo antitumoral effects of the organotelluride catalyst LAB027 in a mouse model of colon cancer and determined its profile of toxicity in vivo. LAB027 induced an overproduction of H(2)O(2) by both human HT29 and murine CT26 colon cancer cell lines in vitro. This oxidative stress was associated with a decrease in proliferation and survival rates of the two cell lines. LAB027 triggered a caspase-independent, ROS-mediated cell death by necrosis associated with mitochondrial damages and autophagy. LAB027 also synergized with the cytotoxic drug oxaliplatin to augment its cytostatic and cytotoxic effects on colon cancer cell lines but not on normal fibroblasts. The opposite effects of LAB027 on tumor and on non-transformed cells were linked to differences in the modulation of reduced glutathione metabolism between the two types of cells. In mice grafted with CT26 tumor cells, LAB027 alone decreased tumor growth compared with untreated mice, and synergized with oxaliplatin to further decrease tumor development compared with mice treated with oxaliplatin alone. LAB027 an organotelluride catalyst compound synergized with oxaliplatin to prevent both in vitro and in vivo colon cancer cell proliferation while decreasing the in vivo toxicity of oxaliplatin. No in vivo adverse effect of LAB027 was observed in this model.

Topics: Animals; Antineoplastic Agents; Apoptosis; Caspases; Catalysis; Cell Line, Tumor; Cell Proliferation; Colonic Neoplasms; Disease Models, Animal; Glutathione; Humans; Hydrogen Peroxide; Mice; Naphthoquinones; Organometallic Compounds; Organoplatinum Compounds; Oxaliplatin; Oxidation-Reduction; Oxidative Stress; Tellurium; Transplantation, Heterologous

Angiogenesis inhibitors are beneficial for the prevention and treatment of angiogenesis-dependent diseases including cancer. Vitamin K2 and K3, which are naphthoquinone derivatives, inhibit angiogenesis. We examined the anti-cancer and anti-angiogenic effects of naphthoquinones and its structurally related compounds. Among these 13 compounds, 1,4-naphthoquinone strongly inhibited both human colon cancer cell (HCT116) growth and angiogenesis. To clarify the anti-angiogenic mechanism, the effects of 1,4-naphthoquinone on human umbilical vein endothelial cell (HUVEC) tube formation, proliferation and chemotaxis were examined. Consequently, 1,4-naphthoquinone inhibited HUVEC functions. These results suggest that 1,4-naphthoquinone may be useful to cancer therapy.

Topics: Animals; Antineoplastic Agents; Cell Division; Cell Line, Tumor; Chemotaxis; Colonic Neoplasms; Endothelium, Vascular; Femoral Artery; HeLa Cells; Humans; Male; Naphthoquinones; Neovascularization, Pathologic; Rats; Rats, Wistar; Umbilical Veins

The use of agents targeting EGFR represents a new frontier in colon cancer therapy. Among these, mAbs and EGFR tyrosine kinase inhibitors seemed to be the most promising. However they have demonstrated scarce utility in therapy, the former being effective only at toxic doses, the latter resulting inefficient in colon cancer. This paper presents studies on a new EGFR inhibitor, FR18, a molecule containing the same naphthoquinone core as shikonin, an agent with great anti-tumor potential. In HT29, a human colon carcinoma cell line, flow cytometry, immunoprecipitation, and Western blot analysis, confocal spectral microscopy have demonstrated that FR18 is active at concentrations as low as 10 nM, inhibits EGF binding to EGFR while leaving unperturbed the receptor kinase activity. At concentration ranging from 30 nM to 5 microM, it activates apoptosis. FR18 seems therefore to have possible therapeutic applications in colon cancer.

Topics: Apoptosis; Colonic Neoplasms; Dose-Response Relationship, Drug; ErbB Receptors; HT29 Cells; Humans; Microscopy, Confocal; Naphthoquinones; Protein Kinase 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

The hollow fiber test has been developed for the preliminary in vivo assessment of cancer chemotherapeutic efficacy of selected natural products. Using this model, we have established growth conditions for HL-60, HUVEC, Ishikawa, KB, KB-V1, LNCaP, Lu1, MCF-7, Mel2, P-388, and SW626 cells implanted at the intraperitoneal (i.p.) and subcutaneous (s.c.) compartments of athymic mice. Five cytotoxic natural product isolates (2-6) were tested in this model, along with paclitaxel (taxol) (1). Among the compounds tested, dioscin (2) and 13-methoxy-15-oxozoapatlin (3) were found to be active, indicating their potential to function as cancer chemotherapeutic agents. On the other hand, ochraceolide A (4), alpha-lapachone (5), and 2-(1-hydroxyethyl)naphtha[2,3-b]furan-4,9-quinone (6), all of which were significantly cytotoxic to cultured mammalian cells, did not mediate significant responses with the hollow fiber model. In further xenograft studies using KB cells implanted at the subcutaneous site, compound 3 mediated a statistically significant response which was consistent with the response observed at the subcutaneous compartment in the hollow fiber tests. In sum, these studies illustrate the usefulness of the hollow fiber model in natural product drug discovery programs. Preliminary indications of potential therapeutic efficacy can be provided quickly at relatively low expense. Agents capable of mediating a response at the subcutaneous site would appear to warrant greatest attention.

Topics: Animals; Biological Factors; Colonic Neoplasms; Diosgenin; Disease Models, Animal; Diterpenes; Drug Screening Assays, Antitumor; Female; Heterocyclic Compounds, 3-Ring; HL-60 Cells; Humans; Inhibitory Concentration 50; KB Cells; Leukemia P388; Male; Melanoma; Mice; Molecular Structure; Naphthoquinones; Ovarian Neoplasms; Paclitaxel; Polymers; Prostatic Neoplasms; Triterpenes; Tumor Cells, Cultured

KILLER/DR5 is a death-domain-containing proapoptotic receptor that binds to the cytotoxic ligand TRAIL. It was originally reported that induction of KILLER/DR5 mRNA following DNA damage was p53-dependent, but some drugs that induce apoptosis can upregulate KILLER/DR5 mRNA expression in cell lines with mutated p53. We further extend those findings by classifying the capability of various apoptosis-inducing drugs to increase the expression of KILLER/DR5 mRNA in a p53-independent manner. beta-Lapachone, a topoisomerase inhibitor, increased KILLER/DR5 mRNA in colon cancer cell lines with wild-type p53 but not with mutant p53. In contrast, betulinic acid, a novel chemotherapeutic compound, induced apoptosis and KILLER/DR5 mRNA in melanoma and glioblastoma cells through a p53-independent mechanism. The synthetic glucocorticoid dexamethasone elevated KILLER/DR5 mRNA in glioblastoma, ovarian cancer, and colon cancer cell lines with mutant p53 undergoing apoptosis, and this induction was inhibited by the transcriptional inhibitor actinomycin D. Although another glucocorticoid, prednisolone, also induced apoptosis, it did not increase KILLER/DR5 mRNA. Finally, the cytokine interferon-gamma (IFN-gamma) induced apoptosis and KILLER/DR5 in cell lines with mutant p53, and the induction of KILLER/DR5 mRNA by IFN-gamma was delayed in cells lacking wild-type STAT1, a transcription factor implicated in IFN-gamma signaling. Similarly, the induction of KILLER/DR5 mRNA by the cytokine TNF-alpha was also delayed in cell lines with mutated STAT1. These findings suggest that KILLER/DR5 may play a role in p53-independent apoptosis induced by specific drugs and warrants further investigation as a novel target for chemotherapy of tumors lacking wild-type p53.

Topics: Antibiotics, Antineoplastic; Apoptosis; Betulinic Acid; Colonic Neoplasms; Dactinomycin; Dexamethasone; DNA-Binding Proteins; Female; Glioblastoma; Glucocorticoids; Humans; Interferon-gamma; Melanoma; Mutation; Naphthoquinones; Ovarian Neoplasms; Pentacyclic Triterpenes; Prednisolone; Receptors, TNF-Related Apoptosis-Inducing Ligand; Receptors, Tumor Necrosis Factor; RNA, Messenger; STAT1 Transcription Factor; Trans-Activators; Triterpenes; Tumor Cells, Cultured; Tumor Suppressor Protein p53; Up-Regulation

The human colon carcinoma cell lines Caco-2 and HT-29 were exposed to three structurally related naphthoquinones. Menadione (MEN), 1,4-naphthoquinone (NQ), and 2,3-dimethoxy-1,4-naphthoquinone (DIM) redoxcycle at similar rates, NQ is a stronger arylator than MEN, and DIM does not arylate thiols. The Caco-2 cell line was particularly vulnerable to NQ and MEN and displayed moderate toxic effects of DIM. The HT-29 cell line was only vulnerable to NQ and MEN after inhibition of DT-diaphorase (DTD) with dicoumarol, whereas dicoumarol did not affect the toxicity of quinones to Caco-2 cells. DTD activity in the HT-29 and Caco-2 cell lines, as estimated by the dicoumarol-sensitive reduction of 2,6-dichlorophenolindophenol, was 393.7 +/- 46.9 and 6.4 +/- 2.2 nmol NADPH x min(-1) x mg protein(-1), respectively. MEN depleted glutathione to a small extent in the HT-29 cell line, but a rapid depletion similar to Caco-2 cells was achieved when dicoumarol was added. The data demonstrated that the DTD-deficient Caco-2 cell line was more vulnerable to arylating or redoxcycling quinones than DTD-expressing cell lines. Exposure of the Caco-2 cell line to quinones produced a rapid rise in protein disulphides and oxidised glutathione. In contrast to NQ and DIM, no intracellular GSSG was observed with MEN. The relatively higher levels of ATP in MEN-exposed cells may account for the efficient extrusion of intracellular GSSG. The reductive potential of the cell as measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide reduction was only increased by MEN and not with NQ and DIM. We conclude that arylation is a major contributing factor in the toxicity of quinones. For this reason, NQ was the most toxic quinone, followed by MEN, and the pure redoxcycler DIM elicited modest toxicity in Caco-2 cells.

Topics: Adenosine Triphosphate; Cell Survival; Colonic Neoplasms; Dicumarol; Glutathione; Glutathione Disulfide; Humans; Kinetics; NAD(P)H Dehydrogenase (Quinone); Naphthoquinones; Neoplasm Proteins; Sulfhydryl Compounds; Tumor Cells, Cultured; Vitamin K

Human colon cancers have a high frequency of p53 mutations, and cancer cells expressing mutant p53 tend to be resistant to current chemo- and radiation therapy. It is thus important to find therapeutic agents that can inhibit colon cancer cells with altered p53 status. beta-Lapachone, a novel topoisomerase inhibitor, has been shown to induce cell death in human promyelocytic leukemia and prostate cancer cells through a p53-independent pathway. Here we examined the effects of beta-lapachone on human colon cancer cells.. Several human colon cancer cell lines, SW480, SW620, and DLD1, with mutant or defective p53, were used. The antiproliferative effects of beta-lapachone were assessed by colony formation assays, cell cycle analysis, and apoptosis analysis, including annexin V staining and DNA laddering analysis. The effects on cell cycle and apoptosis regulatory proteins were examined by immunoblotting.. All three cell lines, SW480, SW620, and DLD1, were sensitive to beta-lapachone, with an IC(50) of 2 to 3 microM in colony formation assays, a finding similar to that previously reported for prostate cancer cells. However, these cells were arrested in different stages of S phase. At 24 hr post-treatment, beta-lapachone induced S-, late S/G2-, and early S-phase arrest in SW480, SW620, and DLD1 cells, respectively. The cell cycle alterations induced by beta-lapachone were congruous with changes in cell cycle regulatory proteins such as cyclin A, cyclin B1, cdc2, and cyclin D1. Moreover, beta-lapachone induced apoptosis, as demonstrated by annexin V staining, flow cytometric analysis of DNA content, and DNA laddering analysis. Furthermore, down-regulation of mutant p53 and induction of p27 in SW480 cells, and induction of pro-apoptotic protein Bax in DLD1 cells may be pertinent to the anti-proliferative and apoptotic effects of beta-lapachone on these cells.. beta-Lapachone induced cell cycle arrest and apoptosis in human colon cancer cells through a p53-independent pathway. For human colon cancers, which often contain p53 mutations, beta-lapachone may prove to be a promising anticancer agent that can target cancer cells, especially those with mutant p53.

Topics: Antibiotics, Antineoplastic; Apoptosis; bcl-2-Associated X Protein; Cell Cycle; Cell Cycle Proteins; Cell Survival; Colonic Neoplasms; DNA, Neoplasm; Humans; Naphthoquinones; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Tumor Cells, Cultured; Tumor Suppressor Protein p53

The effects of two naphthoquinones, juglone and plumbagin, and an isocoumarin, hydrangenol, on intestinal carcinogenesis in rats were examined by dietary exposure during the initiation phase. Starting at 5 weeks of age, male F344 rats were fed the diets containing either of the test chemicals at a concentration of 200 ppm or the control diet without the compounds. At 6 weeks of age, all animals were treated with s.c. injections of azoxymethane (AOM) (15 mg/kg body weight, once weekly for 3 weeks) or saline alone. Animals fed experimental diets were changed to the control diet 1 week after the last carcinogen treatment. Animals given plumbagin together with the carcinogen had a lower incidence (41%) and smaller multiplicity (0.48 +/- 0.62) of tumors in the entire intestine compared with those exposed to carcinogen alone (68% and 1.04 +/- 0.62) (P < 0.05 and < 0.01, respectively). The incidence and multiplicity of tumors in the small intestine (7% and 0.07 +/- 0.25) and the multiplicity of tumors in the entire intestine (0.60 +/- 0.76) of animals treated with juglone and the carcinogen were significantly less than those of animals treated with carcinogen alone (P < 0.05 in each). Hydrangenol tended to decrease the incidence and the multiplicity of tumors in the entire intestine induced by AOM, but the effect was not statistically significant. The present data suggest that the naphthoquinones, juglone and plumbagin, could be promising chemopreventive agents for human intestinal neoplasia.

Topics: Animals; Antineoplastic Agents, Phytogenic; Azo Compounds; Benzopyrans; Colonic Neoplasms; Coumarins; Diet; Intestinal Neoplasms; Isocoumarins; Male; Naphthoquinones; Rats; Rats, Inbred F344

Quinones were studied for their growth inhibitory effect on cultured malignant cells. HCT-15 cells derived from human colon carcinoma were used for these experiments. Quinones used were arbutin in the benzoquinone group, juglone and lawsone in the naphthaquinone group, alizarin, emodin, 1,8-dihydroxyanthraquinone, and anthraquinone in the anthraquinone group, and xanthone. Cultured cells were incubated with various concentrations of the quinones for four days in a 5% CO2 incubator, after which cell numbers were counted and significance of differences was analyzed by Student's t test. Anthraquinones and naphthaquinones used in these experiments were more effective than the monocyclic quinone. The 50% suppression dose was less than 12.5 micrograms/ml for them. The number of OH groups seemed to play an important role in the degree of the cell growth inhibition: anthraquinones with 2 or 3 OH groups were more effective than those with no OH group like, 9,10-dioxoanthracene and xanthone. In fact, anthraquinones with no OH group and xanthone were not significantly effective. Flow cytometric histograms revealed a specific pattern; that is, lawsone and juglone in the naphthaquinone group and alizarin and 1,8-dihydroxy-anthraquinone in the anthraquinone group blocked mainly the S phase, and emodin in the anthraquinone group blocked the G1 to S phase of the cell cycle.

Topics: Anthraquinones; Antineoplastic Agents; Arbutin; Cell Division; Colonic Neoplasms; Humans; Naphthoquinones; Quinones; Tumor Cells, Cultured; Xanthenes; Xanthones

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

Levels of glutathione (GSH) in tumour tissue may be important in determining the clinical response to certain anticancer agents. Recent reports have suggested that D,L-buthionine-S,R-sulphoximine (BSO), a specific inhibitor of GSH synthesis, may be used to deplete tumour cell GSH and thus increase the therapeutic ratio of these agents. We have previously shown that 1-naphthol is a potential antitumour agent, and that its possible metabolite 1,4-naphthoquinone is thiol reactive and capable of redox cycling. It was therefore of interest to investigate the effect of pretreatment with BSO, on the toxicity of these agents, to tumour cells. For comparison we included three other cytotoxic agents, melphalan, helenalin and menadione, the toxicities of which are reported to be modulated by intracellular GSH. Depletion of GSH using BSO did not effect the toxicity of 1-naphthol, or 1,4-NQ but did produce slight potentiation of the cytotoxicities of menadione, helanalin and melphalan. The lack of effect of BSO on 1-naphthol and 1,4-NQ is not easily explained but if one also considers the modest potentiation of cytotoxicity+ achieved with the other agents studied, the potential use of BSO in combined chemotherapy is at best rather modest.

Topics: Antimetabolites; Antineoplastic Agents, Phytogenic; Buthionine Sulfoximine; Cell Line; Cell Survival; Colonic Neoplasms; Drug Evaluation, Preclinical; Glutathione; Humans; Melphalan; Methionine Sulfoximine; Naphthols; Naphthoquinones; Sesquiterpenes; Sesquiterpenes, Guaiane; Vitamin K

1-Naphthol was selectively toxic to human colorectal tumours compared to corresponding normal colonic tissue removed at surgery and maintained in short-term organ culture. Nineteen of 24 tumours studied have shown a significant differential response. Three human colonic adenocarcinoma xenografts, in the short-term organ culture system, displayed the same response to 1-naphthol as primary tumours removed at surgery. 1-Naphthol, 1,2- and 1,4-naphthoquinone were also toxic to two human colonic adenocarcinoma cell lines, LoVo and COLO 206. The selective toxicity of 1-naphthol is mediated in part through an accumulation of 1-naphthol in the tumour tissue due to impaired conjugation by the tumour. The higher concentrations of 1-naphthol may then exert their toxicity either directly or by formation of naphthoquinones. Some indirect evidence was obtained for the possible involvement of 1,2- or 1,4-naphthoquinone in the cytotoxicity of 1-naphthol. Our studies suggest that further studies are warranted of the possible use of 1-naphthol or related compounds as antitumour agents.

Topics: Cell Line; Cell Survival; Colon; Colonic Neoplasms; Humans; Naphthols; Naphthoquinones; Neoplasm Proteins; Organ Culture Techniques; Rectal Neoplasms; Time Factors