Search

Silymarin, a standardized extract from milk thistle fruits has been found to exhibit anti-cancer effects against various cancers. Here, we explored the anti-cancer activity of silymarin and its molecular target in human oral cancer in vitro and in vivo. Silymarin dose-dependently inhibited the proliferation of HSC-4 oral cancer cells and promoted caspase-dependent apoptosis. A human apoptosis protein array kit showed that death receptor 5 may be involved in silymarin-induced apoptosis, which was also shown through western blotting, immunocytochemistry, and reverse transcription-polymerase chain reaction. Silymarin increased cleaved caspase-8 and truncated Bid, leading to accumulation of cytochrome c. In addition, silymarin activated death receptor 5/caspase-8 to induce apoptotic cell death in two other oral cancer cell lines (YD15 and Ca9.22). Silymarin also suppressed tumor growth and volume without any hepatic or renal toxicity in vivo. Taken together, these results provide in vitro and in vivo evidence supporting the anti-cancer effect of silymarin and death receptor 5, and caspase-8 may be essential players in silymarin-mediated apoptosis in oral cancer.

Ethnopharmacological Relevance: Pharbitis Nil (PN) is used as a main component of the existing drug, DA-9701, which was developed to treat functional dyspepsia (FD) in Korea. PN extracts isolated from its seeds have been reported to have anticancer effects., Aim of the Study: The purpose of this study was to investigate the underlying mechanism of the chemotherapeutic effects of PN in lung cancer cells., Materials and Methods: We performed MTT assays, colony formation assays, flow cytometry assays, Western blot analysis, reverse transcription-polymerase chain reaction (RT-PCR), immunofluorescence analysis, and cell counting assays to study the molecular mechanism of chemotherapeutic effects of PN in lung cancer cells., Results: Our results indicate that PN induced autophagy as well as apoptosis. PN inhibited cell proliferation and survival by inducing apoptosis in several lung cancer cell lines. PN-treated cells also exhibited induction of autophagy, as evidenced by increased protein expression levels and punctuate patterns of LC3 II. Moreover, activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2), which plays an important role in autophagy activation, was shown to be related with PN-induced autophagy. Interestingly, pharmacological blockade of autophagy activation with wortmannin and inhibition of ERK1/2 phosphorylation by U0126 markedly enhanced PN-induced apoptosis and reduced cell viability, suggesting that autophagy induced by PN may have a cytoprotective effect by suppressing apoptosis. PN- induced apoptosis was regulated by signal transducer and activator of transcription 3 (STAT3) deactivation. Moreover, decrease of STAT3 activation in PN-treated cells was associated with reduced survivin expression, further demonstrating that PN-induced apoptosis was regulated by STAT3 deactivation., Conclusion: We believe that PN, which is already proven to treat human patients with FD, might be a potential anticancer drug for human lung cancer. In addition, our data suggest that the combination of PN treatment with an autophagy inhibitor or traditional anticancer agents may be an effective anticancer therapy., (Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.)

Cancer cells have been suggested to be more susceptible to oxidative damages and highly dependent on antioxidant capacity in comparison with normal cells, and thus targeting antioxidant enzymes has been a strategy for effective cancer treatment. Sulfiredoxin (Srx) is an enzyme that catalyzes the reduction of sulfinylated peroxiredoxins and thereby reactivates them. In this study we developed a Srx inhibitor, K27 (N-[7-chloro-2-(4-fluorophenyl)-4-quinazolinyl]-N-(2-phenylethyl)-β-alanine), and showed that it induces the accumulation of sulfinylated peroxiredoxins and oxidative stress, which leads to mitochondrial damage and apoptotic death of cancer cells. The effects of K27 were significantly reversed by ectopic expression of Srx or antioxidant N-acetyl cysteine. In addition, K27 led to preferential death of tumorigenic cells over non-tumorigenic cells, and suppressed the growth of xenograft tumor without acute toxicity. Our results suggest that targeting Srx might be an effective therapeutic strategy for cancer treatment through redox-mediated cell death., (Copyright © 2016 Elsevier Inc. All rights reserved.)

In the present study, we developed a novel drug-like self-micellizing anticancer lipid (SMAL), and investigated its anticancer activity and effects on cell death pathways in human colorectal cancer (CRC) cell lines. Three self-assembled nanoparticles were prepared, namely, SMAL102 (lauramide derivative), SMAL104 (palmitamide derivative), and SMAL108 (stearamide derivative) by a thin-film hydration technique, and were characterized for physicochemical and biological parameters. SMAL102 were nanosized (160.23 ± 8.11 nm) with uniform spherical shape, while SMAL104 and SMAL108 did not form spherical shape but formed large size nanoparticles and irregular in shape. Importantly, SMAL102 showed a cytotoxic effect towards CRC cell lines (HCT116 and HT-29), and less toxicity to a normal colon fibroblast cell line (CCD-18Co). Conversely, SMAL104 and SMAL108 did not have an anti-proliferative effect on CRC cell lines. SMAL102 nanoparticles were actively taken up by CRC cell lines, localized in the cell membrane, and exhibited remarkable cytotoxicity in a concentration-dependent manner. The normal colon cell line showed significantly less cellular uptake and non-cytotoxicity as compared with the CRC cell lines. SMAL102 nanoparticles induced caspase-3, caspase-9, and PARP cleavage in HT-29 cells, indicating the induction of apoptosis; whereas LC3B was activated in HCT116 cells, indicating autophagy-induced cell death. Collectively, these results demonstrate that SMAL102 induced cell death via activation of apoptosis and autophagy in CRC cell lines. The present study could be a pioneer for further preclinical and clinical development of such compounds., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Aim of the Study: In this study, we examined the effect of different fractions and components of Chaga mushroom (Inonotus Obliquus) on viability and apoptosis of colon cancer cells. Among them, one component showed the most effective growth inhibition and was identified as ergosterol peroxide by NMR analysis. We investigated the anti-proliferative and apoptosis mechanisms of ergosterol peroxide associated with its anti-cancer activities in human colorectal cancer (CRC) cell lines and tested its anti-tumor effect on colitis-induced CRC developed by Azoxymethane (AOM)/Dextran sulfate sodium (DSS) in a mouse model., Materials and Methods: We used MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays, flow cytometry assays, Western blot analysis, colony formation assays, reverse transcription-polymerase chain reaction (RT-PCR), immunohistochemistry (IHC), and AOM/DSS mouse models to study the molecular mechanism of metastatic activities in CRC cells., Results: Ergosterol peroxide inhibited cell proliferation and also suppressed clonogenic colony formation in HCT116, HT-29, SW620 and DLD-1 CRC cell lines. The growth inhibition observed in these CRC cell lines was the result of apoptosis, which was confirmed by FACS analysis and Western blotting. Ergosterol peroxide inhibited the nuclear levels of β-catenin, which ultimately resulted in reduced transcription of c-Myc, cyclin D1, and CDK-8. Ergosterol peroxide administration showed a tendency to suppress tumor growth in the colon of AOM/DSS-treated mice, and quantification of the IHC staining showed a dramatic decrease in the Ki67-positive staining and an increase in the TUNEL staining of colonic epithelial cells in AOM/DSS-treated mice by ergosterol peroxide for both prevention and therapy., Conclusion: Our data suggest that ergosterol peroxide suppresses the proliferation of CRC cell lines and effectively inhibits colitis-associated colon cancer in AOM/DSS-treated mice. Ergosterol peroxide down-regulated β-catenin signaling, which exerted anti-proliferative and pro-apoptotic activities in CRC cells. These properties of ergosterol peroxide advocate its use as a supplement in colon cancer chemoprevention., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Non-steroidal anti-inflammatory drugs (NSAIDs) have been suggested as the potential new class of preventive or therapeutic antitumor agents. The aim of the present study was to evaluate the antitumor activity of the novel NSAID, CG100649. CG100649 is a novel NSAID dual inhibitor for COX-2 and carbonic anhydrase (CA)-I/-II. In the present study, we investigated the alternative mechanism by which CG100649 mediated suppression of the colon cancer growth and development. The anchorage‑dependent and -independent clonogenic assay showed that CG100649 inhibited the clonogenicity of human colon cancer cells. The flow cytometric analysis showed that CG100649 induced the G2/M cell cycle arrest in colon cancer cells. Animal studies showed that CG100649 inhibited the tumor growth in colon cancer xenograft in nude mice. Furthermore, quantitative PCR and FACS analysis demonstrated that CG100649 upregulated the expression of TNF-related apoptosis-inducing ligand (TRAIL) receptors (DR4 and DR5) but decreased the expression of decoy receptors (DcR1 and DcR2) in colon cancer cells. The results showed that CG100649 treatment sensitized TRAIL‑mediated growth suppression and apoptotic cell death. The combination treatment resulted in significant repression of the intestinal polyp formation in APCmin/+ mice. Our data clearly demonstrated that CG100649 contains preventive and therapeutic activity for colon cancer. The present study may be useful for identification of the potential benefit of the NSAID CG100649, for the achievement of a better treatment response in colon cancer.

Background: Recent studies have shown that glucosamine inhibits the proliferation of various human cancer cell lines and downregulates the activity of COX-2, HIF-1α, p70S6K, and transglutaminase 2. Because the IGF-1R/Akt pathway is a common upstream regulator of p70S6K, HIF-1α, and COX-2, we hypothesized that glucosamine inhibits cancer cell proliferation through this pathway., Methods: We used various in vitro assays including flow cytometry assays, small interfering RNA (siRNA) transfection, western blot analysis, MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays, reverse transcription-polymerase chain reaction, and in vivo xenograft mouse model to confirm anticancer activities of glucosamine and to investigate the molecular mechanism., Results: We found that glucosamine inhibited the growth of human non-small cell lung cancer (NSCLC) cells and negatively regulated the expression of IGF-1R and phosphorylation of Akt. Glucosamine decreased the stability of IGF-1R and induced its proteasomal degradation by increasing the levels of abnormal glycosylation on IGF-1R. Moreover, picropodophyllin, a selective inhibitor of IGF-1R, and the IGF-1R blocking antibody IMC-A12 induced significant cell growth inhibition in glucosamine-sensitive, but not glucosamine-resistant cell lines. Using in vivo xenograft model, we confirmed that glucosamine prohibits primary tumor growth through reducing IGF-1R signalling and increasing ER-stress., Conclusions: Taken together, our results suggest that targeting the IGF-1R/Akt pathway with glucosamine may be an effective therapeutic strategy for treating some type of cancer.

Midazolam is a widely used anesthetic of the benzodiazepine class that has shown cytotoxicity and apoptosisinducing activity in neuronal cells and lymphocytes. This study aims to evaluate the effect of midazolam on growth of K562 human leukemia cells and HT29 colon cancer cells. The in vivo effect of midazolam was investigated in BALB/c-nu mice bearing K562 and HT29 cells human tumor xenografts. The results show that midazolam decreased the viability of K562 and HT29 cells by inducing apoptosis and S phase cell-cycle arrest in a concentration-dependent manner. Midazolam activated caspase-9, capspase-3 and PARP indicating induction of the mitochondrial intrinsic pathway of apoptosis. Midazolam lowered mitochondrial membrane potential and increased apoptotic DNA fragmentation. Midazolam showed reactive oxygen species (ROS) scavenging activity through inhibition of NADPH oxidase 2 (Nox2) enzyme activity in K562 cells. Midazolam caused inhibition of pERK1/2 signaling which led to inhibition of the anti-apoptotic proteins Bcl-XL and XIAP and phosphorylation activation of the pro-apoptotic protein Bid. Midazolam inhibited growth of HT29 tumors in xenograft mice. Collectively our results demonstrate that midazolam caused growth inhibition of cancer cells via activation of the mitochondrial intrinsic pathway of apoptosis and inhibited HT29 tumor growth in xenograft mice. The mechanism underlying these effects of midazolam might be suppression of ROS production leading to modulation of apoptosis and growth regulatory proteins. These findings present possible clinical implications of midazolam as an anesthetic to relieve pain during in vivo anticancer drug delivery and to enhance anticancer efficacy through its ROS-scavenging and pro-apoptotic properties.

Epidermal growth factor receptor (EGFR) is one of the most promising targets for cancer therapy. Here, we show the in vitro and in vivo anticancer effects and associated mechanisms of KO-202125, one of the synthesized aristolactam analogs, as a novel EGFR inhibitor, in EGFR-overexpressing cancer cell lines. KO-202125 showed more effective growth inhibition and apoptosis induction than gefitinib, a representative EGFR inhibitor, in various EGFR-overexpressing human cancers including estrogen receptor (ER)-negative MDA-MB-231 human breast cancer cells. Epidermal growth factor receptor phosphorylation at Tyr1068 was reduced and, consequently, the association of EGFR with p85 was decreased by KO-202125 treatment in MDA-MB-231 cell lines. This led to inactivation of the PI3K/Akt pathway, and consequently suppression of activation of the Wnt pathway and enhancement of the nuclear import of p27Kip1. KO-202125 treatment in nude mice injected with MDA-MB-231 cells showed inhibition of tumor growth without toxicity. Collectively, our results showed the possibility of KO-202125 as an effective therapy agent of EGFR-overexpressing cancer cells through reduced EGFR activity and downregulation of the Akt pathway., (© 2011 Japanese Cancer Association.)

Insulin-like growth factor binding protein-3 (IGFBP-3), a major IGF-binding protein in human serum, regulates the growth of non-small cell lung cancer (NSCLC) cells through IGF-dependent and IGF-independent mechanisms. However, the role of IGFBP-3 in lung cancer metastasis is not well known. In the present study, we showed that noncytotoxic doses of adenoviral or recombinant IGFBP-3 significantly decreased the migration and invasion of H1299 and A549 NSCLC cells. Furthermore, treatment of human lung fibroblasts with recombinant IGFBP-3 suppressed their ability to stimulate the invasion of H1299 cells. Overexpression of IGFBP-3 markedly reduced lung metastasis of A549 cells in an experimental animal model system and prolonged the survival time of the animals. Urokinase-type plasminogen activator (uPA) inhibitor treatment or uPA small interfering RNA transfection of A549 and H1299 cells resulted in a significant decrease in invasion. Corresponding ELISA, Western blot, gelatin zymogram, and semiquantitative reverse transcription-PCR analyses revealed that IGFBP-3 reduced the expression of uPA mRNA through IGF-independent mechanisms. The specific role of uPA in anti-invasive activity of IGFBP-3 was further confirmed in NSCLC cells, in which uPA expression/activity was suppressed by the transfection with synthetic small interfering RNA or by the treatment with uPA inhibitor or induced by the infection with an adenoviral vector. IGFBP-3 also decreased the expression/activity of matrix metalloproteinase-2 through IGF-dependent but uPA-independent pathways. Taken together, our data suggest that IGFPB-3 effectively block uPA- and matrix metalloproteinase-2-stimulated invasion pathways, ultimately reducing lung cancer cell metastasis. Our findings indicate that IGFBP-3 may be a promising anti-invasive and antimetastatic therapeutic agent in lung cancer.

Tobacco carcinogens induce Akt activation and lung carcinogenesis. We previously demonstrated that deguelin, a natural plant product, specifically inhibits the proliferation of premalignant and malignant human bronchial epithelial cells by blocking Akt activation. To evaluate the ability of deguelin to block tobacco carcinogen-induced lung tumorigenesis, we evaluated the in vivo effects of deguelin on Akt activation and lung tumorigenesis in transgenic mice in which Akt expression was induced by tamoxifen and in 4-(methylnitrosoamino)-1-(3-pyridyl)-1-butanone (NNK)/benzo(a)pyrene (BaP)-treated A/J mice. Deguelin suppressed Akt activation in vivo, as measured by immunohistochemistry and immunoblotting, and statistically significantly reduced NNK/BaP-induced lung tumor multiplicity, volume, and load in A/J mice, as monitored by microcomputed tomography image analysis, with no detectable toxicity. These results indicate that deguelin warrants consideration as a chemopreventive agent for early-stage lung carcinogenesis in a clinical lung cancer chemoprevention trial.

Cancer prevention is effective and reduces health care costs because cancer is often a preventable disease that can be affected by lifestyle factors. Therefore, researchers are interested in discovering natural compounds that have anticancer activities, such as delaying the development of cancer and preventing its progression. One such natural agent is ginseng (Panax ginseng), which is traditionally used in some parts of the world as a popular remedy for various diseases including cancer. We hypothesized that the ginsenoside Rp1, a component of ginseng, reduces cancer cell proliferation through inhibition of the insulin-like growth factor 1 receptor (IGF-1R)/Akt pathway. We first tested the efficacy of Rp1 against human breast cancer cell lines. Treatment with Rp1 inhibited breast cancer cell proliferation and inhibited both anchorage-dependent and -independent breast cancer cell colony formation. In addition, treatment with 20 μM Rp1 induced cycle arrest and apoptosis-mediated cell growth suppression. Our findings further indicated that Rp1 decreased the stability of the IGF-1R protein in breast cancer cells. Therefore, we suggest that Rp1 has potential as an anticancer drug and that IGF-1R is an important target for treatment and prevention of breast cancer. [ABSTRACT FROM AUTHOR]

Silymarin, a standardized extract from milk thistle fruits has been found to exhibit anti-cancer effects against various cancers. Here, we explored the anti-cancer activity of silymarin and its molecular target in human oral cancer in vitro and in vivo. Silymarin dose-dependently inhibited the proliferation of HSC-4 oral cancer cells and promoted caspase-dependent apoptosis. A human apoptosis protein array kit showed that death receptor 5 may be involved in silymarin-induced apoptosis, which was also shown through western blotting, immunocytochemistry, and reverse transcription-polymerase chain reaction. Silymarin increased cleaved caspase-8 and truncated Bid, leading to accumulation of cytochrome c. In addition, silymarin activated death receptor 5/caspase-8 to induce apoptotic cell death in two other oral cancer cell lines (YD15 and Ca9.22). Silymarin also suppressed tumor growth and volume without any hepatic or renal toxicity in vivo. Taken together, these results provide in vitro and in vivo evidence supporting the anti-cancer effect of silymarin and death receptor 5, and caspase-8 may be essential players in silymarin-mediated apoptosis in oral cancer. [ABSTRACT FROM AUTHOR]