Phenethyl isothiocyanate (PEITC) promotes G2/M phase arrest via p53 expression and induces apoptosis through caspase- and mitochondria-dependent signaling pathways in human prostate cancer DU 145 cells

Phenethyl isothiocyanate (PEITC), one of many compounds found in cruciferous vegetables, has been reported as a potential anticancer agent. In earlier studies, PEITC was shown to inhibit cell growth and induction of apoptosis in many cancer cell lines. However, no report has shown whether PEITC can induce apoptosis in human prostate cancer cells. Herein, we aimed to determine whether PEITC has anticancer activity in DU 145 human prostate cancer cells. As a result, we found that PEITC induced a dose-dependent decrease in cell viability through induction of cell apoptosis and cell cycle arrest in the G(2)/M phase of DU 145 cells. PEITC induced morphological changes and DNA damage in DU 145 cells. The induction of G(2)/M phase arrest was mediated by the increase of p53 and WEE1 and it reduced the level of CDC25C protein. The induction of apoptosis was mediated by the activation of caspase-8-, caspase-9- and caspase-3-depedent pathways. Results also showed that PEITC caused mitochondrial dysfunction, increasing the release of cytochrome c and Endo G from mitochondria, and led cell apoptosis through a mitochondria-dependent signaling pathway. This study showed that PEITC might exhibit anticancer activity and become a potent agent for human prostate cancer cells in the future.

Crude extracts of Agaricus brasiliensis induce apoptosis in human oral cancer CAL 27 cells through a mitochondria-dependent pathway

In Taiwan, oral cancer is the fourth leading cause of male cancer mortality, and is still increasing. The Basiodiomycete, Agaricus brasiliensis Murill (ABM) is a dietary mushroom and has been known for its immuneenhancing, antitumor, antioxidation, antiviral and antimutagenesis functions. However, the exact anticancer mechanisms of ABM on human oral cancer cells are still unclear. In the present study, we investigated the effects of 50% ethanol crude extracts and hot water extracts of ABM on oral cancer CAL 27 cells. We observed that 0.9 mg/ml and 0.7 mg/ml of ABM 50% ethanol crude extracts and hot water, respectively, caused morphological changes and significantly reduced cell viability after 48-h treatment. The results showed that both extracts of ABM inhibited cell proliferation, increased the Ca(2+) release, reduced the mitochondria membrane potential (ΔΨm), and caused cell cycle arrest in the G(0)/G(1) phase, which contributed to apoptosis. Additionally, ABM induced DNA fragmentation, a characteristic of apoptosis and the expressions of apoptosis-related proteins, including apoptosis-inducing factor, cytochrome c, and caspase-3, were increased. Overall, we demonstrated that 50% ethanol crude extract and hot water extracts of ABM were able to induce apoptotic cell death in CAL 27 cells via the release of cytochrome c from mitochondria into the cytoplasm and activation of caspase-3 in vitro.

Danthron inhibits murine WEHI-3 cells in vivo, and enhances macrophage phagocytosis and natural killer cell cytotoxic activity in leukemic mice

Danthron has been shown to induce apoptotic cell death, and inhibit migration and invasion of human gastric or brain cancer cells in vitro. However, there is no report addressing whether danthron affects murine leukemia cells or immune responses in vivo. Herein, this study focused on the in-vivo effects of danthron on WEHI-3 leukemia in mice and immune responses in vivo. The results indicated that danthron reduced spleen weight and increased the percentage of cells with CD3 and CD19 markers, indicating that differentiation of the precursors of T- and B-cells was promoted in the leukemic mice. The results also showed that danthron promoted the activity of phagocytosis by macrophages isolated from the peritoneal cavity but had no effect on peripheral blood mononuclear cells. Danthron also promoted natural killer cell cytocytic activity at an effector and target cell ratio of 100:1 in comparison with leukemic animals in vivo. Taken together, these results demonstrated that application of danthron might affect WEHI-3 leukemia in mice and modulate immune responses in vivo.

Zanthoxylum ailanthoides Sieb and Zucc. extract inhibits growth and induces cell death through G2/M-phase arrest and activation of apoptotic signals in colo 205 human colon adenocarcinoma cells

The effects of 50% ethanolic stem extracts of Zanthoxylum ailanthoides Sieb and Zucc. (ZASZ) on the cell viability, cell cycle and apoptosis were investigated in a human colon adenocarcinoma cell line (colo 205). The results demonstrated that ZASZ induced morphological changes and decreased the cell viability. ZASZ promoted Wee1, checkpoint kinase 2 (CHK2), p21 and p53 levels, decreased cyclin B and cdc25c associated with that led to G(2)/M phase arrest. ZASZ-triggered apoptosis was confirmed by 4' -6-diamidino-2-phenylindole (DAPI) staining and DNA gel electrophoresis. ZASZ increased the levels of glucose-regulated protein 78 (GRP78) and growth arrest and DNA damage inducible gene 153 (GADD153), and promoted an increase of reactive oxygen species (ROS) and Ca(2+) release, and loss of mitochondrial membrane potential (ΔΨ(m)) accompanied by cytochrome c release that was due to the decrease of Bcl-2 and increase of Bax levels in the colo 205 cells. ZASZ also induced the protein levels of apoptosis-inducing factor (AIF) and endonuclease G (Endo G), increased the levels of caspase-3, -7 and -9, and stimulated the levels of fatty acid synthase (Fas) and Fas ligand in the colo 205 cells. ZASZ contains phenolic compounds, including flavone, chlorogenic acid and isofraxidin, among which, flavone was found to be the most effective in reducing cell viability and proliferative responses in the colo 205 cells. ZASZ induces cytotoxicity and apoptosis in colo 205 cells which provides the rationale for studies in animal models on the utilization of ZASZ as a potential cancer therapeutic compound.

Gallic acid suppresses the migration and invasion of PC-3 human prostate cancer cells via inhibition of matrix metalloproteinase-2 and -9 signaling pathways

Epidemiological studies have demonstrated that a natural diet or consumption of fruits or vegetables can decrease the risk of cancer development. Cancer cells can migrate to and invade other organs or tissues that cause more difficulty to treat them and this also results in the need for treatments targeting multiple cellular pathways. Gallic acid (GA) has been demonstrated to possess multiple biological activities including anticancer function. However, no report exist on GA inhibited invasion and migration of human prostate cancer cells. We investigated the effects of migration and invasion in GA-treated PC-3 human prostate cancer cells with a series of in vitro experiments. Boyden chamber transwell assay was used to examine the migration and invasion of PC-3 cells. Western blotting, real-time PCR and gelatin zymography were used for determining the protein levels, gene expression and enzyme activities of matrix metalloproteinase-2 (MMP-2) and -9 in vitro. Results indicated that GA inhibited the invasion and migration of PC-3 cells and these effects are dose-dependent. GA inhibited the protein levels of MMP-2 and -9, son of sevenless homolog 1 (SOS1), growth factor receptor-bound protein 2 (GRB2), protein kinase C (PKC) and nuclear factor-κ B (NF-κB) p65, c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase 1/2 (ERK1/2), p38, p-AKT (Thr308) and p-AKT (Ser473), but it promoted the levels of phosphatidylinositol 3-kinase (PI3K) and AKT in PC-3 cells. GA also reduced the enzyme activities of MMP-2 and -9 in the examined cells. Moreover, the down-regulation of focal adhesion kinase (FAK) and Ras homolog gene family, member A (Rho A) mRNA expression levels, and up-regulation of the tissue inhibitor of metalloproteinase-1 (TIMP1) gene levels occurred in GA-treated PC-3 cells after 24 h treatment. Based on these observations, we suggest that GA might modulate through blocking the p38, JNK, PKC and PI3K/AKT signaling pathways and reducing the NF-κB protein level, resulting in the inhibition of MMP-2 and -9 of PC-3 human prostate cancer cells.

The synthesized novel fluorinated compound (LJJ-10) induces death receptor- and mitochondria-dependent apoptotic cell death in the human osteogenic sarcoma U-2 OS cells

We designed the 6-fluoro-2-(3-fluorophenyl)-4-substituted anilinoquinazoline derivatives as less toxic anti-cancer candidates. Our result demonstrated that LJJ-10 has greater cytotoxicity than that of the other compounds in human osteogenic sarcoma U-2 OS cells. LJJ-10-induced apoptosis was associated with enhancing ROS generation, DNA damage, and an increase of the protein levels of Fas, FasL, FADD, caspase-8, cytochrome c, Apaf-1, AIF, Endo G, caspase-9 and caspase-3 in U-2 OS cells. LJJ-10-triggered growth inhibition was significantly attenuated by N-acetylcysteine, cyclosporine A, anti-FasL monoclonal antibody, and caspase-8, -9 and -3 specific inhibitors in U-2 OS cells. We suggest that LJJ-10-induced apoptotic cell death in U-2 OS cells through death receptor- and mitochondria-dependent apoptotic signaling pathways.

Diallyl sulfide induces cell cycle arrest and apoptosis in HeLa human cervical cancer cells through the p53, caspase- and mitochondria-dependent pathways

Diallyl sulfide (DAS), one of the main active constituents of garlic, causes growth inhibition of cancer cells in vitro and promotes immune responses in vivo in experimental settings. However, its effects on the induction of cell cycle and apoptosis in human cervical cancer cells are still unclear. The aims of this study were to explore the anti-cancer effects of DAS in HeLa human cervical cancer cells and to investigate the underlying mechanisms in vitro. Cytotoxicity and apoptosis in HeLa human cervical cancer cells were examined by the morphological changes, viability assay, 4',6-Diamidino-2-phenylindole dihydrochloride (DAPI) staining, comet assay, Western blotting and confocal microscopy examination. The results showed that DAS treatment for 24-72 h resulted in a marked decrease in cell viability time- and dose-dependently. Flow cytometric analysis showed that a 48-h treatment of 75 µM DAS induced G0/G1 cell cycle arrest and sub-G1 phase (apoptosis) in HeLa cells. Typical apoptotic nucleus alterations were observed by fluorescence microscopy in HeLa cells after exposure to DAS using DAPI staining. Cells treated with different concentrations of DAS also showed changes typical of apoptosis such as morphological changes, DNA damage and fragmentation, dysfunction of mitochondria, cytochrome c release and increased expression of pro-caspase-3 and -9. DAS also promoted the release of AIF and Endo G from mitochondria in HeLa cells. In conclusion, DAS induced G0/G1 cell cycle arrest and apoptosis in HeLa cells through caspase- and mitochondria and p53 pathways providing further understanding of the molecular mechanisms of DAS action in cervical cancer. This study, therefore, revealed that DAS significantly inhibits the growth and induces apoptosis of human cervical cancer HeLa cells in vitro.

New bichalcone analogs as NF-κB inhibitors and as cytotoxic agents inducing Fas/CD95-dependent apoptosis

A series of novel bichalcone analogs were synthesized and evaluated in lipopolysaccharide (LPS)-activated microglial cells as inhibitors of nitric oxide (NO) and for in vitro anticancer activity using a limited panel of four human cancer cell lines. All analogs inhibited NO production. Compounds 4 and 11 exhibited optimal activity with IC(50) values of 0.3 and 0.5 μM, respectively, and were at least 38-fold better than the positive control. A mechanism of action study showed that both compounds significantly blocked the nuclear translocation of NF-κB p65 and up-regulation of iNOS at 1.0 μM. Compound 4 and three other analogs (3, 20, and 23) exerted significant in vitro anticancer activity GI(50) values ranging from 0.70 to 13.10 μM. A mode of action study using HT-29 colon cancer cells showed that 23 acts by inducing apoptosis signaling.

Kaempferol induced apoptosis via endoplasmic reticulum stress and mitochondria-dependent pathway in human osteosarcoma U-2 OS cells

Kaempferol is a natural flavonoid. Previous studies have reported that kaempferol has anti-proliferation activities and induces apoptosis in many cancer cell lines. However, there are no reports on human osteosarcoma. In this study, we investigate the anti-cancer effects and molecular mechanisms of kaempferol in human osteosarcoma cells. Our results demonstrate that kaempferol significantly reduces cell viabilities of U-2 OS, HOB and 143B cells, especially U-2 OS cells in a dose-dependent manner, but exerts low cytotoxicity on human fetal osteoblast progenitor hFOB cells. Comet assay, DAPI staining and DNA gel electrophoresis confirm the effects of DNA damage and apoptosis in U-2 OS cells. Flow cytometry detects the increase of cytoplasmic Ca(2+) levels and the decrease of mitochondria membrane potential. Western blotting and fluorogenic enzymatic assay show that kaempferol treatment influences the time-dependent expression of proteins involved in the endoplasmic reticulum stress pathway and mitochondrial signaling pathway. In addition, pretreating cells with caspase inhibitors, BAPTA or calpeptin before exposure to kaempferol increases cell viabilities. The anti-cancer effects of kaempferol in vivo are evaluated in BALB/c(nu/nu) mice inoculated with U-2 OS cells, and the results indicate inhibition of tumor growth. In conclusion, kaempferol inhibits human osteosarcoma cells in vivo and in vitro.

Cantharidin induces apoptosis in human bladder cancer TSGH 8301 cells through mitochondria-dependent signal pathways

Cantharidin has shown potent anticancer activities on many types of human cancer cells. This study was performed to elucidate whether mitochondria and caspases are involved in the modulation of apoptosis and cell cycle arrest by cantharidin in human bladder cancer cells. The effect of cantharidin on cell cycle arrest, apoptosis, caspases, reactive oxygen species (ROS) and mitochondrial membrane potential (ΔΨ(m)) were measured by flow cytometry, and the levels of apoptosis-associated proteins and its regulatory molecules were studied by Western blotting. Cantharidin-induced apoptosis and DNA damage was determined by flow cytometric analysis, DAPI staining and Comet assay. After cantharidin treatment, the active forms of caspase-3, -8 and -9 were promoted. Cantharidin-induced apoptosis was associated with enhanced ROS and Ca(2+) generations, caused DNA damage, decreased the levels of ΔΨ(m) and promoted Endo G and AIF released from mitochondria. Cantharidin-induced G0/G1 arrest was associated with a marked decrease in the protein expressions of cyclin E and Cdc25c but promoted the levels of p21 and p-p53. Cantharidin-induced apoptosis was accompanied with up-regulation of the protein expression of Bax and PARP, but down-regulation of the protein levels of Bcl-2, resulting in dysfunction of mitochondria then led to Endo G and AIF release for causing induction of apoptosis.

Cantharidin induces G2/M phase arrest and apoptosis in human colorectal cancer colo 205 cells through inhibition of CDK1 activity and caspase-dependent signaling pathways

Cantharidin (CTD) is a traditional Chinese medicine and an effective component isolated from blister beetle, and it has been demonstrated to have anticancer, antibiotic, antivirus activities and immune-regulated functions. It has been reported that CTD induces cell cycle arrest and apoptosis in many cancer cell types. However, there are no reports showing that CTD would induce cell cycle arrest and apoptosis in human colorectal cancer colo 205 cells. In this study, we studied colo 205 cells which were treated with CTD and demonstrated its molecular mechanisms in apoptosis. CTD induced growth inhibition, G2/M phase arrest and apoptosis in colo 205 cells. The IC50 is 20.53 µM in CTD-treated colo 205 cells. DAPI/TUNEL double staining and Annexin V assays were used to confirm the apoptotic cell death in colo 205 cells after CTD exposure. CTD caused G2/M arrest, down-regulated CDK1 activity, decreased Cyclin A, Cyclin B, CDK1 and increased CHK1 and p21 protein levels. Colorimetric assays also indicated that CTD triggered activities of casapse-8, -9 and -3 in colo 205 cells. Moreover, CTD increased ROS production and decreased the level of mitochondrial membrane potential (ΔΨm) in colo 205 cells. Consequently, CTD-induced growth inhibition was significantly attenuated by N-acetylcysteine (NAC, a scavenger). CTD stimulated the protein levels of Fas/CD95, the caspase-3 active form, cytochrome c and Bax, but suppressed the protein levels of pro-caspase-8, pro-caspase-9 and Bcl-2, determined by Western blot analysis. Based on our observations, we suggest that CTD is able to induce G2/M phase arrest and apoptosis in colo 205 cells through inhibition of CDK1 activity and caspase-dependent signaling pathways.

The roles of AIF and Endo G in the apoptotic effects of benzyl isothiocyanate on DU 145 human prostate cancer cells via the mitochondrial signaling pathway

It is well known that the response of cancer cells to chemotherapeutic drugs involves the activation of apoptotic pathways. Benzyl isothiocyanate (BITC) is an important compound found in plant food and has been shown to have anti-cancer effects on human cancer cells, but its effect on prostate cancer cells in vitro remains unknown. The aim of the present study was to investigate the effects of BITC on DU 145 human prostate cancer cells in order to clarify whether a time/concentration range for optimal BITC-induced apoptosis exists and to find the associated signaling pathway. Cell morphological changes, percentage of cell viability, DNA damage and apoptosis in DU 145 cells were examined by phase-contrast microscopy, flow cytometric assay, 4',6-diamidine-20-phenylindole dihydrochloride staining, comet assay and Western blotting analysis. The results indicate that BITC induces cell morphological changes, decreases the percentage of viable cells (induction of cell cytotoxicity), and induces DNA damage and apoptosis in DU 145 cells in a time- and dose-dependent manner. Flow cytometric assays indicated that BITC promoted reactive oxygen species and Ca2+ productions and decreased the levels of mitochondrial membrane potential (ΤYm), while the pre-treatment with N-acetylcysteine caused an increase in the percentage of viable cells. BITC also promoted caspase-3, -8 and -9 activities. Furthermore, when cells were pre-treated with the caspase-3 inhibitor and then treated with BITC, this led to an increase in the percentage of viable cells. Confocal laser microscopy examination indicated that BITC promoted the expression of AIF and Endo G, which were released from the mitochondria in DU 145 cells. In conclusion, BITC induces apoptosis in DU 145 cells through the release of AIF and Endo G from the mitochondria and also promotes caspase-3 activation.

Antitumor activity of capsaicin on human colon cancer cells in vitro and colo 205 tumor xenografts in vivo

Capsaicin was reported to inhibit cancer cell growth. The aim of this study was to evaluate the antitumor potential of capsaicin by studying antitumor activity in vitro as well as in vivo. The in vitro studies are to examine the effects of capsaicin on human colon cancer colo 205 cells after exposure to capsaicin. The results showed that capsaicin induced cytotoxic effects in a time- and dose-dependent manner and increased reactive oxygen species (ROS) and Ca(2+) but decreased the level of mitochondrial membrane potential (ΔΨ(m)) in colo 205 cells. Data from Western blotting analysis indicated that the levels of Fas, cytochrome c, and caspases were increased, leading to cell apoptosis. Capsaicin decreased the levels of anti-apoptotic proteins such as Bcl-2 and increased the levels of pro-apoptotic proteins such as Bax. Capsaicin-induced apoptosis in colo 205 cells was also done through the activations of caspase-8, -9 and -3. In vivo studies in immunodeficient nu/nu mice bearing colo 205 tumor xenografts showed that capsaicin effectively inhibited tumor growth. The potent in vitro and in vivo antitumor activities of capsaicin suggest that capsaicin might be developed for the treatment of human colon cancer.

Triptolide induces apoptosis in human adrenal cancer NCI-H295 cells through a mitochondrial-dependent pathway

Triptolide, the main active component obtained from Tripterygium wilfordii Hook. f, has been reported to present potent immunosuppressive and anti-inflammatory biological activities. It has been previously shown that due to the cytotoxicity of triptolide it has a limited use in the clinic. Although numerous studies have shown that triptolide induced apoptosis in many human cancer cells there is no report to show triptolide-induced apoptosis in human adrenal cancer cells. We treated the human adrenal cancer NCI-H295 cells with triptolide in vitro and investigated its cytotoxic effects. The cytotoxicity was examined and quantitated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay and the viability of inhibition and apoptosis was determined by flow cytometric assay, using propidium iodide (PI) staining for apoptosis. Flow cytometric assay also used for the determination of reactive oxygen species (ROS) production and the levels of mitochondrial membrane potential (ΔΨm), and the caspase-3 and -9 activation in NCI-H295 cells. Western blotting was used for examining the changes of apoptotic associated proteins. The results indicated that triptolide induced cytotoxicity (decreased the percentage of viable cells) and induced sub-G1 phase (apoptosis) occurring in NCI-H295 cells and those effects are dose-dependent. Results also showed that triptolide promoted the production of ROS and decreased the levels of ΔΨm in examined NCI-H295 cells. The results showed that triptolide promoted the levels of cytochrome c, Apaf-1, AIF, Endo G, caspase-9 and -3 which were analyzed by Western blotting. These results suggest that triptolide is able to induce apoptosis on NCI-H295 cells through the mitochondrial-dependent signal pathway.

Death receptor 5-mediated TNFR family signaling pathways modulate γ-humulene-induced apoptosis in human colorectal cancer HT29 cells

A component from Emilia sonchifolia (L.) DC, γ-humulene, was investigated. Significantly decreased cell viability of human colorectal cancer HT29 cells in a dose-dependent manner with IC50 53.67±2.99 μM for 24-h treatment was found. γ-Humulene induced apoptotic cell death and apoptosis was confirmed by morphological assessment. The staining with propidium iodide (PI) and flow cytometric analysis also showed that γ-humulene significantly promoted the sub-G1 phase (an apoptotic population) in HT29 cells. Colorimetric assays indicated that pretreatment with a specific inhibitor of caspase-8 (Z-IETD-FMK) significantly reduced activities of caspase-8 and caspase-3 in examined HT29 cells. γ-Humulene stimulated the death receptor 5 (DR5), DR4, Fas-associated protein with death domain (FADD), the cleavage of caspase-8 and cleavage caspase-3, but reduced the protein levels of cellular Fas-associated death-domain-like IL-1ß-converting enzyme inhibitory protein (c-FLIP) by Western blot analysis. Consequently, γ-humulene-triggered cell death was significantly attenuated by DR5 siRNA and the caspase-8 inhibitor. Based on our results, we suggest that γ-humulene induced apoptotic cell death in HT29 cells through a DR5-mediated caspase-8 and -3-dependent signaling pathway. Therefore, this agent might be useful for developing new therapeutic regimens for treatment of colorectal cancer in the future.

Danthron, an anthraquinone derivative, induces DNA damage and caspase cascades-mediated apoptosis in SNU-1 human gastric cancer cells through mitochondrial permeability transition pores and Bax-triggered pathways

Anthraquinones have been shown to induce apoptosis in different types of tumor cells, but the mechanisms of danthron-induced cytotoxicity and apoptosis in human gastric cancer cells have not been adequately explored. This study investigated the roles of caspase cascades, ROS, DNA damage, mitochondrial disruption, and Bax and Bcl-2 proteins in danthron-induced apoptosis of SNU-1 human gastric cancer cells, a commonly used cell culture system for in vitro studies. Cells were incubated with different concentrations of danthron in a time- and/or dose-dependent manner. Cell morphological changes (shrinkage and rounding) were examined by a phase-contrast microscope, whereas cell viability and apoptotic populations were determined by flow cytometric analysis using propidium iodide (PI) and annexin V-FITC staining. The fluorescent DAPI nucleic acid stain and Comet assay were applied to detect danthron-induced chromatin condensation (an apoptotic characteristic) and DNA damage. Increasing the levels of caspase-3, -8, and -9 activities was involved in danthron-induced apoptosis, and they could be attenuated by inhibitors of specific caspases, indicating that danthron triggered the caspase-dependent apoptotic pathway. Further studies with flow cytometric analyses indicated that cellular levels of ROS, cytosolic Ca(2+), and mitochondrial permeability transition (MPT) pore opening were increased, but the level of mitochondrial membrane potential (ΔΨ(m)) was decreased. Also, the ratio of Bax/Bcl-2 levels and other proapoptotic proteins associated with modulating the ΔΨ(m) were up-regulated. Apoptotic signaling was also stimulated after exposure to danthron and determined by Western blotting and real-time PCR analyses. In summary, it is suggested that danthron-induced apoptotic cell death was involved in mitochondrial depolarization, which led to release of cytochrome c, apoptosis-inducing factor (AIF), and endonuclease G (Endo G) and caused the activation of caspase-9 and -3 in SNU-1 human gastric cancer cells.

Chrysophanol induces necrosis through the production of ROS and alteration of ATP levels in J5 human liver cancer cells

Anthraquinone compounds have been shown to induce apoptosis in different cancer cell types. Effects of chrysophanol, an anthraquinone compound, on cancer cell death have not been well studied. The goal of this study was to examine if chrysophanol had cytotoxic effects and if such effects involved apoptosis or necrosis in J5 human liver cancer cells. Chrysophanol induced necrosis in J5 cells in a dose- and time-dependent manner. Non-apoptotic cell death was induced by chrysophanol in J5 cells and was characterized by caspase independence, delayed externalization of phosphatidylserine and plasma membrane disruption. Blockage of apoptotic induction by a general caspase inhibitor (z-VAD-fmk) failed to protect cells against chrysophanol-induced cell death. The levels of reactive oxygen species production and loss of mitochondrial membrane potential (DeltaPsi(m)) were also determined to assess the effects of chrysophanol. However, reductions in adenosine triphosphate levels and increases in lactate dehydrogenase activity indicated that chrysophanol stimulated necrotic cell death. In summary, human liver cancer cells treated with chrysophanol exhibited a cellular pattern associated with necrosis and not apoptosis.

Allyl isothiocyanate triggers G2/M phase arrest and apoptosis in human brain malignant glioma GBM 8401 cells through a mitochondria-dependent pathway

Isothiocyanates (ITCs) are present as glucosinolates in various cruciferous vegetables. Allyl isothiocyanate (AITC) is one of the common naturally occurring isothiocyanates. Recent studies have shown that AITC significantly inhibited survival of leukemia HL-60, bladder cancer UM-UC-3 and colon cancer HT-29 cells in vitro. In this study, we demonstrate that AITC significantly decreased proliferation and viability of human brain malignant glioma GBM 8401 cells in a dose-dependent manner with IC50 9.25+/-0.69 microM for 24 h-treatment. The analysis of cell cycle distribution also showed that AITC induced significantly G2/M arrest and sub-G1 phase (apoptotic population) in GBM 8401 cells. AITC markedly reduced the CDK1/cyclin B activity and protein levels by CDK1 activity assay and Western blot analysis. AITC-induced apoptotic cell death and this evidence was confirmed by morphological assessment and DAPI staining. Pretreatment with specific inhibitors of caspase-3 (Z-DEVE-FMK) and -9 (Z-LEHD-FMK) significantly reduced caspase-3 and -9 activity in GBM 8401 cells. Western blot analysis and colorimetric assays also displayed that AITC caused a time-dependent increase in cytosolic cytochrome c, pro-caspase-9, Apaf-1, AIF, Endo G and the stimulated caspase-9 and -3 activity. Our results suggest that AITC is a potent anti-human brain malignant glioma drug and it shows a remarkable action on cell cycle arrest before commitment for apoptosis is reached.

Phenethyl isothiocyanate inhibited tumor migration and invasion via suppressing multiple signal transduction pathways in human colon cancer HT29 cells

Phenethyl isothiocyanate (PEITC), one of the major compounds from dietary cruciferous vegetables, has been found to have antitumor properties and therefore could generate special interest for the development of chemopreventive and/or chemotherapeutic agent for human cancers. In the primary studies, we found that PEITC induced cytotoxic effect (decreased the percentage of viable cells) in human colon cancer HT29 cells. Here, in this study, we are the first to report the antimetastatic effect of PEITC in HT29 human colon cancer cells. The results show that PEITC exhibited an inhibitory effect on the abilities of adhesion, migration, and invasion by Boyden chamber assay. Western blotting examination indicated that PEITC exerted an inhibitory effect on the SOS-1, PKC, ERK1/2 and Rho A for causing the inhibitions of MMP-2 and -9 then followed by the inhibition of invasion and migration of HT29 cells in vitro. PEITC also affected Ras, FAK, PI3K or inhibited GRB2, NF-κB, iNOS and COX-2 for causing the inhibition of cell proliferation in HT29 cells. Real-time PCR also showed that PEITC inhibited the gene expressions of MMP-2, -7, -9, FAK and Rho A after PEITC treatment for 48 h in HT29 cells. PEITC also inhibited the activities of AKT, ERK, JNK and PKC. Our results provide a new insight into the mechanisms and functions of PEITC which inhibit migration and invasion of HT29 human colon cancer cells. These results suggest that molecular targeting of NF-κB led to the inhibition of MMP-2, -7, and -9 and it might be a useful strategy for the inhibition of migration and invasion on human colon cancer.

Apigenin induces apoptosis in human lung cancer H460 cells through caspase- and mitochondria-dependent pathways

Apigenin (4,5,7-trihydroxyflavone), a promising chemopreventive agent presented in fruits and vegetables, has been shown to induce cell cycle arrest and apoptosis in many types of human cancer cell lines. However, there is no available information to address the effects of apigenin on human lung cancer H460 cells. In the present studies, H460 cells were treated with apigenin for different time and then were analyzed for the morphological changes, induction of apoptosis, protein levels associated with apoptosis and results in dose-dependent induction of morphological changes, decrease in the percentage of viability, induced DNA damage and apoptosis; down-modulation of the protein expression of Bid, Bcl-2, procaspase-8; up-regulation of protein levels of Bax, caspase-3, AIF, cytochrome c, GRP78 and GADD153; decreased the levels of mitochondrial membrane potential and increased the productions of reactive oxygen species (ROS) and Ca2+ in H460 cells. Taken together, this is the first systematic in vitro study showing the involvement of apoptosis regulatory proteins as potential molecular targets of apigenin in human lung cancer H460 cells.

2-(3-Methoxyphenyl)-6, 7-methylenedioxoquinolin-4-one, a novel synthetic compound, inhibited migration and invasion in TSGH8301 human bladder cancer cells

Matrix metalloproteinases (MMPs) play an important role in the invasion, metastasis and angiogenesis of cancer cells. Many agents have been shown to inhibit the cancer cell migration and invasion by suppression of MMPs. 2-(3-Methoxyphenyl)-6,7-methylenedioxoquinolin-4-one (MMEQ) is a derivative compound synthesized from quinolin and the purpose of this study is to determine whether or not cell migration would be reduced in human bladder cancer TSGH8301 cells after MMEQ treatment. Wound healing assay and boyden chamber assay were used in cell migration and invasion determinations. Cell migration and invasion inhibited by MMEQ exerted an inhibitory effect on the sevenless homolog-1 (SOS-1), protein kinase c (PKC), extracellular signal-regulated kinase (ERK) and Rho A for causing the inhibitions of MMP-2 and -9, and then followed by the inhibitions of invasion and migration. MMEQ also affected FAK, PI3K or inhibited growth factor receptor-bound protein 2 (GRB2), nuclear factor kappaB (NF-κB), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) for cell proliferation inhibition. Therefore, MMEQ may serve as a drug in the prevention of tumor metastasis of bladder cancer in the future.

Dietary effect of Antrodia Camphorate extracts on immune responses in WEHI-3 leukemia BALB/c mice

Antrodia camphorata has been recognized to be a traditional Chinese medicine for abdominal pain, diarrhea, and to protect against hepatitis virus infection. Several ingredients derived from A. camphorata possess various pharmacological and biological activities such as antioxidant and anticancer. In this study, its ability to promote immune responses and to exhibited antileukemia activity in WEHI-3 leukemia BALB/c mice were investigated. The results indicated A. camphorata significantly prolonged the survival rate and prevented the body weight loss in leukemia mice. Four mg/kg of A. camphorata treatment significantly decreased the weight of the spleen. Both doses (2 and 4 mg/kg) of A. camphorata did not affect Mac-3 marker in leukocytes. However, the 4 mg/kg of A. camphorata decreased the levels of CD11b and both doses of treatment increased CD3 and CD19. With lipopolysaccharide stimulation, the 4 mg/kg of A. camphorata promoted the significant proliferation of leukocytes; but with concanavalin A stimulation, both doses promoted the significant proliferation of leukocytes. YAC-1 target cells were killed by NK cells from the mice after treatment with A. camphorata at 4 mg/kg in target cells at a ratio of 50:1. The percentage of macrophages with phagocyted at A. camphorata treatment increased, and these effects were in dose-dependent manners.

The novel quinolone CHM-1 induces DNA damage and inhibits DNA repair gene expressions in a human osterogenic sarcoma cell line

20-Fluoro-6,7-methylenedioxy-2-phenyl-4-quino-lone (CHM-1) has been reported to induce cell cycle arrest and apoptosis in many types of cancer cells. However, there is no available information to show CHM-1 affecting DNA damage and expression of associated repair genes. Herein, we investigated whether or not CHM-1 induced DNA damage and affected DNA repair gene expression in U-2 OS human osterogenic sarcoma cells. The comet assay showed that incubation of U-2 OS cells with 0, 0.75, 1.5, 3 and 6 μM of CHM-1 led to a longer DNA migration smear (comet tail). DNA gel electrophoresis showed that 3 μM of CHM-1 for 24 and 48 h treatment induced DNA fragmentation in U-2 OS cells. Real-time PCR analysis showed that treatment with 3 μM of CHM-1 for 24 h reduced the mRNA expression levels of ataxia telangiectasia mutated (ATM), ataxia-telangiectasia and Rad3-related (ATR), breast cancer 1, early onset (BRCA1), 14-3-3sigma (14-3-3σ), DNA-dependent serine/threonine protein kinase (DNA-PK) and O(6)-methylguanine-DNA methyltransferase (MGMT) genes in a time-dependent manner. Taken together, the results indicate that CHM-1 caused DNA damage and reduced DNA repair genes in U-2 OS cells, which may be the mechanism for CHM-1-inhibited cell growth and induction of apoptosis.

Houttuynia cordata Thunb extract inhibits cell growth and induces apoptosis in human primary colorectal cancer cells

It is reported that Houttuynia cordata Thunb. (HCT), a traditional Chinese herbal medicine, has many biological properties such as antiviral, antibacterial and antileukemic activities. However, the molecular mechanisms of cytotoxicity and apoptosis in human primary colorectal cancer cells are not clear. In this study, whether HCT induced cytotoxicity in primary colorectal cancer cells obtained from three patients was investigated. The results indicated that HCT inhibited growth of cancer cells in a dose-dependent manner. After treatment with HCT (250 μg/ml) for 24 h, cells exhibited chromatin condensation (an apoptotic characteristic). HCT increased reactive oxygen species (ROS) production and decreased the mitochondrial membrane potential (ΔΨ(m)) in examined cells. Mitochondria-dependent apoptotic signaling pathway was shown to be involved as determined by increase in the levels of cytochrome c, Apaf-1, and caspase-3 and -9. The decrease in the level of ΔΨ(m) was associated with an increase in the BAX/BCL-2 ratio which led to activation of caspase-9 and -3. Based on our results, HCT induced apoptotic cell death in human primary colorectal cancer cells through a mitochondria-dependent signaling pathway.