Adenosine induces cell cycle arrest and apoptosis via cyclinD1/Cdk4 and Bcl-2/Bax pathways in human ovarian cancer cell line OVCAR-3

Adenosine is a regulatory molecule with widespread physiological effects in almost every cells and acts as a potent regulator of cell growth. Adenosine has been shown to inhibit cell growth and induce apoptosis in the several cancer cells via caspase activation and Bcl-2/Bax pathway. The present study was designed to understand the mechanism underlying adenosine-induced apoptosis in the OVCAR-3 human ovarian cancer cells. MTT viability, BrdU and cell counting assays were used to study the cell proliferation effect of adenosine in presence of adenosine deaminase inhibitor and the nucleoside transporter inhibitor. Cell cycle analysis, propidium iodide and annexin V staining, caspase-3 activity assay, cyclinD1, Cdk4, Bcl-2 and Bax protein expressions were assessed to detect apoptosis. Adenosine significantly inhibited cell proliferation in a concentration-dependent manner in OVCAR-3 cell line. Adenosine induced cell cycle arrest in G0/G1 phase via Cdk4/cyclinD1-mediated pathway. Adenosine induced apoptosis, which was determined by Annexin V-FITC staining and increased sub-G1 population. Moreover, down-regulation of Bcl-2 protein expression, up-regulation of Bax protein expression and activation of caspase-3 were observed in response to adenosine treatment. The results of this study suggest that extracellular adenosine induced G1 cell cycle arrest and apoptosis in ovarian cancer cells via cyclinD1/ Cdk4 and Bcl-2/Bax pathways and caspase-3 activation. These data might suggest that adenosine could be used as an agent for the treatment of ovarian cancer.     

The effect of fatty acid-CoA ligase 4 on the growth of hepatic cancer cells

In this study, we detected the expression of FACL4 mRNA in 40 patients with hepatic carcinoma and its adjacent normal tissues by semi-quantitative RT-PCR. The changes of proliferation and apoptosis of hepatic cancer cell line HepG2 with FACL4 protein expression were examined by MTT and flow cytometry respectively after FACL4 selective inhibitor triacsin C treatment. The activity related to apoptosis of proteinases, caspase-3, caspase-8 and caspase-9, were detected by colorimetry. The expression related to apoptosis of protein, wt-p53, Bax and Bcl-2, in HepG2 cells were evaluated by S-P immunocytochemical dyeing. The results were: (1) FACL4 mRNA was expressed in 95.0% of hepatic cancer tissue, while the positive expression of FACL4 mRNA was 82.5% in cancer adjacent normal liver tissues. Moreover, there was a statistically significant increased in quantity of FACL4 mRNA in cancer tissues compared with adjacent normal liver tissues. (2) The concentration of triacsin C (0.5-2 mg/L) could inhibit the proliferation and induce the apoptosis of HepG2 cells significantly in a dose- and time-effect. (3) During the apoptosis of HepG2 cells induced by triacsin C, flow cytometry coupled with Rhodamine 123 dyeing showed that mitochondrial transmembrane potential of HepG2 declined significantly, and the activity of caspase-9 and caspase-3 increased more remarkably than caspase-8. Besides, the increased apoptosis was accompanied by increased Bax, and decreased wtp53 and Bcl-2 protein levels. The present study suggested that FACL4 might play a role in the growth of hepatic cancer cells. FACL4 selective inhibitor triacsin C leads to a marked growth inhibition of human liver tumor cells, based on the inhibition of proliferation and induction of apoptosis. The apoptotic process was mediated by intrinsic mitochondrial apoptotic pathway due to activation of caspase-9 and caspase-3. The increased apoptosis was accompanied by upregulation of Bax, and decreased wt-p53 and Bcl-2 protein level.     

pseudo-G-Rh2 induces mitochondrial-mediated apoptosis in SGC-7901 human gastric cancer cells

This study was designed to investigate the effect of pseudo-G-Rh2, a novel metabolite of ginsenoside Rh2, on the apoptosis of SGC-7901 human gastric cancer cells. Pseudo-G-Rh2 demonstrated antitumor activity and significantly inhibited the proliferation of SGC-7901 cells in a concentration-dependent manner. After treatment with pseudo-G-Rh2, SGC-7901 cells showed typical apoptotic morphological features, such as chromatin condensation and DNA fragmentation. Pseudo-G-Rh2 could induce mitochondrial membrane potential loss, which led to the release of cytochrome c (Cyt?c), Smac/Diablo and apoptosis-inducing factor (AIF) to the cell cytoplasm. Furthermore, pseudo-G-Rh2 exposure not only decreased the expression of the Bcl-2 protein but also increased the expression of the Bax protein and the activities of caspase-9 and caspase-3 in SGC-7901 cells. These results demonstrated that pseudo-G-Rh2 inhibited the proliferation of SGC-7901 cells by initiating apoptosis. Pseudo-G-Rh2-induced apoptosis was associated with a drop in the mitochondrial transmembrane potential, down-regulation of Bcl-2, up-regulation of Bax and activation of caspase-9 and caspase-3.     

Enhanced effect of gemcitabine by emodin against pancreatic cancer in vivo via cytochrome C-regulated apoptosis

Gemcitabine is currently the best treatment available for pancreatic cancer, but causes high toxicity. Agents that can enhance the effects of gemcitabine with no or low toxicity are needed for the treatment of pancreatic cancer. Emodin, a natural anthraquinone derivative, is one such agent that has been shown to induce apoptosis in other tumor cells via down-regulation of Bcl-2/Bax and promoting the release of Cytochrome C (CytC), but with very low toxicity. The aim of this study was to evaluate whether emodin can enhance the effect of gemcitabine on pancreatic cancer in?vitro and in?vivo and to investigate the possible mechanisms of the enhancement. In?vitro, emodin inhibited the proliferation of the SW1990 cell line and potentiated the apoptosis induced by gemcitabine, which was demonstrated by activation of caspase-3 in the combination group. In?vivo, tumors from nude mice subcutaneously injected with SW1990 cells and treated with a combination of emodin (40?mg/kg) and gemcitabine (80?mg/kg) showed significant reductions in volume, Ki-67 proliferation index and expression of the Bcl-2/Bax ratio (compared with tumors from mice treated with sodium chloride, emodin alone (40?mg/kg) or gemcitabine alone (125?mg/kg), which induced increasing release of CytC from the mitochondria to the cytoplasm and triggered caspase-3 activation leading to apoptosis. Taken together, our results suggest that emodin improved the anti-tumor effect of gemcitabine, even at a lower dose of gemcitabine which could decrease the toxicity of chemotherapy, on transplanted tumors of the SW1990 cell line through the enhancement of apoptosis induced by gemcitabine, the mechanism of which may be through down-regulation of the Bcl-2/Bax ratio and promoting release of CytC from the mitochondria into the cytoplasm.     

ALEX1 Regulates Proliferation and Apoptosis in Breast Cancer Cells

Background: Arm protein lost in epithelial cancers, on chromosome X (ALEX) is a novel subgroup withinthe armadillo (ARM) family, which has one or two ARM repeat domains as opposed to more than six-thirteenrepeats in the classical Armadillo family members. Materials and Methods: In the study, we explore the biologicalfunctions of ALEX1 in breast cancer cells. Overexpression of ALEX1 and silencing of ALEX1 were performedwith SK-BR3 and MCF-7 cell lines. Cell proliferation and colony formation assays, along with flow cytometry,were carried out to evaluate the roles of ALEX1. Results: ALEX1 overexpression in SK-BR3 breast cancer cellsinhibited proliferation and induced apoptosis. Furthermore, depletion of ALEX1 in MCF-7 breast cancer cellsincreased proliferation and inhibited apoptosis. Additional analyses demonstrated that the overexpression ofALEX1 activated the intrinsic apoptosis cascades through up-regulating the expression of Bax, cytosol cytochromec, active caspase-9 and active caspase-3 and down-regulating the levels of Bcl-2 and mitochondria cytochrome c.Simultaneouly, silencing of ALEX1 inhibited intrinsic apoptosis cascades through down-regulating the expressionof Bax, cytosol cytochrome c, active caspase-9, and active caspase-3 and up-regulating the level of Bcl-2 andmitochondria cytochrome c. Conclusions: Our data suggest that ALEX1 as a crucial tumor suppressor genehas been involved in cell proliferation and apoptosis in breast cancer, which may serve as a novel candidatetherapeutic target.     

线粒体凋亡途径在TA2小鼠自发性乳腺癌中的作用

比较TA2小鼠正常乳腺、乳腺癌前病变和乳腺癌组织中细胞增殖和凋亡的情况,通过检测线粒体凋亡途径中Bcl-2、Bax、Caspase-3和Caspase-9在乳腺组织中的表达,初步确定线粒体凋亡途径在TA2小鼠自发乳腺癌中可能发挥的作用。方法:收集正常TA2成年雌鼠的乳腺组织（NC组）和TA2自发性乳腺癌癌前病变组织（SBC-b组）和乳腺癌组织（SBC-t组）,采用免疫组化方法检测各组乳腺上皮细胞中PCNA、Bcl-2、Bax、Caspase-3和Caspase-9的表达并计算增殖指数（PI）;采用TUNEL方法检测细胞凋亡并计算凋亡指数（AI）;采用Real-time PCR和Western blot方法检测组织中Bcl-2、Bax、Caspase-3和Caspase-9蛋白表达及mRNA相对表达水平。结果:免疫组化染色,Real-time PCR以及Western blot结果一致显示,SBC-b组Bcl-2,Bax,Caspase-3和Caspase-9表达均明显高于NC（P<0.01或P<0.05）;SBC-t组中除Bcl-2高于NC外,其余蛋白表达均明显低于NC（P<0.01）,但bcl-2,bax和Caspase-3 mRNA表达均显著高于NC（P<0.01）,Caspase-9 mRNA略高于NC,但无统计学意义（P>0.05）。结论:线粒体途径可能参与了TA2鼠自发性乳腺癌的发生,其通过刺激部分乳腺上皮细胞凋亡,破坏了TA2小鼠乳腺上皮细胞增殖和凋亡的平衡,以致乳腺癌发生。      

Evodiamine,a constituent of Evodiae Fructus,induces anti-proliferating effects in tumor cells

We found that evodiamine, a major alkaloidal component of Evodiae Fructus (Goshuyu in Japan), inhibited proliferation of several tumor cell lines, but had less effect on human peripheral blood mononuclear cells (PBMC). We used human cervical cancer cells, HeLa, as a model to elucidate the molecular mechanisms of evodiamine-induced tumor cell death. The results showed that evodiamine induced oligonucleosomal fragmentation of DNA in HeLa cells and increased the activity of caspase-3, but not that of caspase-1, in vitro . Both evodiamine-induced DNA fragmentation and caspase-3 activity were effectively inhibited by a caspase-3 inhibitor, z-DEVD-fmk (z-Asp-Glu-Val-Asp-fmk). In addition, evodiamine increased the expression of the apoptosis inducer Bax, but decreased the expression of the apoptosis suppressor Bcl-2 in mitochondria. Taken together, our data indicated that evodiamine alters the balance of Bcl-2 and Bax gene expression and induces apoptosis through the caspase pathway in HeLa cells. (Cancer Sci 2003; 94: 92–98)     

δ-生育三烯酚诱导人肝癌HepG2细胞凋亡的机制研究

目的:探讨δ-生育三烯酚诱导人肝癌HepG2细胞凋亡的作用机制.方法:应用MTT法检测δ-生育三烯酚对人肝癌HepG2细胞增殖的影响,应用高内涵活细胞成像系统检测δ-生育三烯酚对人肝癌HepG2细胞凋亡率、细胞周期以及线粒体膜电位的影响,Western印迹法检测δ-生育三烯酚对人肝癌HepG2细胞凋亡相关蛋白(如caspase-3、caspase-8、caspase-9、Bcl-2、Bax、tBid和cytochrome C)表达的影响.结果:δ-生育三烯酚呈浓度依赖性地抑制肝癌HepG2细胞生长并诱导其凋亡,其机制为δ-生育三烯酚降低线粒体膜电位,并诱导cytochrome C从线粒体释放到细胞质中,调控Bcl-2家族蛋白表达(如上调Bax及tBid蛋白的表达,下调Bcl-2蛋白的表达),继而引起caspase-3、caspase-8和caspase-9的活化,最终导致肝癌 HepG2细胞凋亡.结论:δ-生育三烯酚可能通过线粒体途径及膜死亡受体途径共同诱导人肝癌细胞 HepG2凋亡.     

番荔枝内酯单体squamocin诱导人肺腺癌A549细胞凋亡的实验研究

目的 观察番荔枝内酯单体squamocin对人肺腺癌A549细胞的体外增殖抑制及诱导凋亡的作用,并探讨squamocin诱导肿瘤细胞凋亡的机制。方法 MTT法检测不同浓度的squamocin对人肺腺癌A549细胞体外增殖的影响;流式细胞仪检测squamocin干预在不同时间点对人肺腺癌A549细胞凋亡率的影响;Western blotting检测squamocin干预前后细胞凋亡相关蛋白caspase-3、Bax和Bcl-2的表达情况。结果 MTT法显示,squamocin对人肺腺癌A549细胞的体外抑制作用随着squamocin浓度的增加和作用时间的延长而增强,24、48、72h半数抑制浓度（IC50）分别为16.54、9.28、6.17μg／ml;流式细胞仪检测显示,在24、48、72h实验组人肺腺癌A549细胞凋亡率之间及其与阴性对照组比较,差异均有统计学意义（P＜0.01）,其中实验组72h的细胞凋亡率最高,为（51.87±1.79）％Western blotting显示,squamocin干预后细胞凋亡相关蛋白caspase-3和Bax表达上调,Bcl-2表达明显下调。结论 squamocin可诱导人肺腺癌A549细胞凋亡,这可能与squamocin上调细胞凋亡相关蛋白caspase-3、Bax表达以及降低抑制细胞凋亡基因Bcl-2表达有关。     

奈达铂体外诱导人卵巢癌顺铂耐药细胞凋亡的机制

目的探讨研究奈达铂（NDP）体外对人卵巢癌顺铂原发耐药细胞株SKOV3和继发耐药株SKOV3/DDP的抑制作用及其机制。方法采用MTT法检测体外不同时间不同浓度的NDP对SKOV3及SKOV3/DDP细胞的杀伤作用,计算半数抑制浓度(IC50);流式细胞术(FCM)测定给药前后细胞凋亡率及周期分布变化;半定量PCR分析凋亡基因Bcl-2,Bax,caspase-3,caspase-9及反应肿瘤细胞侵袭力的基因MMP-2的表达变化。结果NDP能明显抑制SKOV3及SKOV3/DDP生长,呈时间-剂量依赖性;流式结果显示随时间、浓度增加,SKOV3和SKOV3/DDP细胞凋亡明显增加,S期细胞的比例增加,差异均有统计学意义（P<0.05）。与对照组相比,Bcl-2、MMP-2表达减少,Bax,caspase-3,caspase-9表达增加。结论NDP可抑制SKOV3和SKOV3/DDP细胞增殖,其机制可能与诱导细胞凋亡,细胞S期阻滞,下调Bcl-2及上调Bax,caspase-3,caspase-9的表达有关;同时可下调MMP-2的表达,有利于降低卵巢癌细胞的侵袭力。     

Cav3.1在宫颈癌组织中的表达及靶向下调Cav3.1对宫颈癌HeLa细胞增殖和凋亡的影响

目的:分析Cav3.1在宫颈癌组织中的表达及靶向下调Cav3.1对人宫颈癌HeLa细胞增殖和凋亡的影响。方法:采用免疫组织化学染色法检测Cav3.1在68例宫颈癌组织和40例非癌宫颈组织中的表达;实时定量聚合酶链反应（Real-time PCR）、Western blot检测宫颈癌HeLa细胞中Cav3.1的表达;采用siRNA瞬时转染技术靶向下调Cav3.1表达,CCK-8检测下调Cav3.1表达后宫颈癌HeLa细胞增殖情况,流式细胞仪检测下调Cav3.1表达后宫颈癌HeLa细胞凋亡情况;Western blot检测宫颈癌HeLa细胞中Bcl-2、Bax、Cleaved-Caspase3的表达。结果:Cav3.1在宫颈癌组织中的表达显著高于对照组（P＜0.01）。宫颈癌HeLa细胞中Cav3.1的表达水平显著高于HcerEpic 细胞（P＜0.01）。与对照组相比,siRNA-Cav3.1组的Cav3.1相对表达水平显著下降（P＜0.01）。与空白对照组、mock组相比,siRNA-Cav3.1组HeLa细胞的增殖能力减弱,凋亡能力增强,差异有统计学意义（P＜0.01）。Western blot显示siRNA-Cav3.1组Bax、Cleaved-Caspase3的相对表达量比对照组升高,而Bcl-2降低(P＜0.01)。结论:Cav3.1在宫颈癌组织和细胞中高表达。靶向下调Cav3.1可以抑制HeLa细胞的增殖、促进其凋亡。Cav3.1在宫颈癌的生物学行为中可能起着关键的作用,有望成为一种新的有效的宫颈癌治疗靶点及肿瘤检测的分子生物学标志物。     

LIGHT sensitizes IFNgamma-mediated apoptosis of MDA-MB-231 breast cancer cells leading to down-regulation of anti-apoptosis Bcl-2 family members

LIGHT is a new member of the tumor necrosis factor superfamily, which binds to lymphotoxin beta receptor, herpes virus entry mediator, or TR6. This work was carried out to elucidate the molecular mechanism of LIGHT-sensitized, interferon gamma (IFNgamma)-mediated apoptosis of MDA-MB-231 cells. It was revealed that LIGHT treatment resulted in down-regulation of anti-apoptosis Bcl-2 family member: Bcl-2, Bcl-X(L), Bag-1, and Mcl-1; up-regulation of pro-apoptosis Bcl-2 family member: Bak and Ser (112)-phosphor-Bad; down-regulation of pro-apoptosis Bcl-2 member Bax; the other pro-apoptosis member Bid remains unaltered. LIGHT treatment also resulted in activation of caspase-3, caspase-6, caspase-7, caspase-8, caspase-9, DFF45, and PARP. However, caspase activation and caspase activity, especially caspase-3 activity, is not required for LIGHT-induced apoptosis of MDA-MB-231 cells, since caspase-3 inhibitor, benzyloxycarbonyl-Asp-Glu-Val-Asp-fluoromethylketone, and a broad range caspase inhibitor, benzyloxycarbonyl-val-ala-asp-fluoromethylketone failed to block the apoptosis induced by LIGHT and IFNgamma in MDA-MB-231 cells. In summary, LIGHT-sensitized IFNgamma-mediated apoptosis of MDA-MB-231 cells is probably through down-regulation of anti-apoptosis Bcl-2 family members; it could be caspase (especially caspase-3)-independent, even though extensive caspase activation was observed.     

Grape seed proanthocyanidins induce apoptosis and inhibit metastasis of highly metastatic breast carcinoma cells

The strategies available for the treatment of metastatic breast cancer are limited. Dietary botanicals may have a better protective effect on this disease. We therefore investigated the effects of grape seed proanthocyanidins (GSPs) on a highly metastatic mouse mammary carcinoma cell line. In vitro treatment of breast cancer cells, 4T1, MCF-7 and MDA-MB-468, with GSPs resulted in significant inhibition of cellular proliferation and viability, and induction of apoptosis in 4T1 cells in a time- and dose-dependent manner. Further analysis indicated an alteration in the ratio of Bax/Bcl-2 proteins in favor of apoptosis, and the knockdown of Bax using Bax siRNA transfection of 4T1 cells resulted in blocking of GSPs-induced apoptosis. Induction of apoptosis was associated with the release of cytochrome c, increased expression of Apaf-1 and activation of caspase 3 and poly (ADP-ribose) polymerase. Treatment with the pan-caspase inhibitor (Z-VAD-FMK) resulted in partial but significant inhibition of apoptosis in 4T1 cells suggesting the involvement of both caspase activation-dependent and activation-independent pathways in the apoptosis of 4T1 cells induced by GSPs. The effects of dietary GSPs were then examined using an in vivo model in which 4T1 cells were implanted subcutaneously in Balb/c mice. Dietary GSPs (0.2 and 0.5%, w/w) significantly inhibited the growth of the implanted 4T1 tumor cells and increased the ratio of Bax:Bcl-2 proteins, cytochrome c release, induction of Apaf-1 and activation of caspase 3 in the tumor microenvironment. Notably, the metastasis of tumor cells to the lungs was inhibited significantly and the survival of the mice enhanced. These data suggest that GSPs possess chemotherapeutic efficacy against breast cancer including inhibition of metastasis.     

miR-122-5p通过靶向CREB1抑制食管癌细胞及移植瘤的生长

背景与目的:miR-122在多种肿瘤中表达异常,参与肿瘤细胞增殖、凋亡等,而cAMP反应元件结合蛋白1(cAMP response element-binding protein 1,CREB1)参与食管癌发展过程,研究miR-122-5p通过靶向CREB1对食管癌细胞及移植瘤生长的作用及机制.方法:选取2017年11...     

Regulation of p53-, Bcl-2- and caspase-dependent signaling pathway in xanthorrhizol-induced apoptosis of HepG2 hepatoma cells

Xanthorrhizol is a sesquiterpenoid compound extracted from the rhizome of Curcuma xanthorrhiza. This study investigated the antiproliferative effect and the mechanism of action of xanthorrhizol on human hepatoma cells, HepG2, and the mode of cell death. An antiproliferative assay using methylene blue staining revealed that xanthorrhizol inhibited the proliferation of the HepG2 cells with a 50% inhibition of cell growth (IC50) value of 4.17 +/- 0.053 microg/ml. The antiproliferative activity of xanthorrhizol was due to apoptosis induced in the HepG2 cells and not necrosis, which was confirmed by the Tdt-mediated dUTP nick end labeling (TUNEL) assay. The xanthorrhizol-treated HepG2 cells showed typical apoptotic morphology such as DNA fragmentation, cell shrinkage and elongated lamellipodia. The apoptosis mediated by xanthorrhizol in the HepG2 cells was associated with the activation of tumor suppressor p53 and down-regulation of antiapoptotic Bcl-2 protein expression, but not Bax. The levels of Bcl-2 protein expression decreased 24-h after treatment with xanthorrhizol and remained lower than controls throughout the experiment, resulting in a shift in the Bax to Bcl-2 ratio thus favouring apoptosis. The processing of the initiator procaspase-9 was detected. Caspase-3 was also found to be activated, but not caspase-7. Xanthorrhizol exerts antiproliferative effects on HepG2 cells by inducing apoptosis via the mitochondrial pathway.     

Growth of human prostate cancer cells is significantly suppressed in vitro with sodium butyrate through apoptosis

Histone deacetylase inhibitors (HDACis) have shown significant antiproliferative and apoptotic properties in various types of cancer cells, including prostate cancer cells, and are therefore being evaluated as a treatment modality. However, the mechanism by which sodium butyrate (SB) induces apoptosis is not completely understood. We focused on SB which exists in the intestine and is therefore expected to have less adverse effects. In this study, three prostate cancer cell lines (LNCaP, DU145 and PC-3) were treated in vitro with different concentrations of SB. Cell proliferation was studied by the XTT assay; cell cycle analysis and induction of apoptosis were studied by laser scanning cytometry. Western blot analysis was used to study p21, p27, CDK2, CDK4, CDK6, caspase-3, caspase-7, Fas, FADD, TRADD, Bcl-2 and Bax protein expression. SB inhibited cell growth and induced apoptosis in a concentration-dependent manner in human prostate cancer cells (LNCaP, DU145 and PC-3). Western blot analysis showed dose-dependent increases of p21 levels in DU145 and PC-3 cells, and dose-dependent decreases of CDK2, CDK4, CDK6 and procaspase-3 protein levels in all three prostate cancer cell lines. Bcl-xL was significantly down-regulated in DU145 cells, and Bcl-2 was significantly down-regulated in PC-3 and LNCaP cells. No significant changes were observed in procaspase-7, TRADD and Bax expression, although slight decreases in Fas and FADD expression were seen in all three prostate cancer cell lines. Analysis of cell morphology using laser scanning microscopy detected condensed and fragmented nuclei. In conclusion, SB induces G1 and G2 arrest by increasing p21 expression resulting in CDK2, CDK4 and CDK6 down-regulation. SB potently induced apoptosis, which was accompanied by DNA fragmentation, down-regulated Bcl-2 in LNCaP and PC-3 cells, Bcl-xL in DU145 cells, and down-regulated procaspase-3, but not procaspase-7, in these human prostate cancer cell lines. These results suggest that SB may serve as a new modality for the treatment of hormone refractory prostate cancer.     

Therapeutic effect of arsenic trioxide (As2O3) on cervical cancer in vitro and in vivo through apoptosis induction

Arsenic trioxide (As2O3) induces apoptosis in certain types of cancer cells. But the detailed mechanisms of As2O3 efficacy are not completely known. Here we demonstrate that As2O3 has a therapeutic effect on cervical cancer in vitro and in vivo. We investigated the As2O3-induced apoptosis in various cervical cancer cells. The apoptosis was triggered by mitochondrial pathway and associated with dissociation of Bcl-2 from Bax and VDAC, then the release of cytochrome c from Bax and VDAC channel, resulting in the activation of caspase-9 and caspase-3. The overexpression of Bcl-2 counteracted the As2O3-mediated apoptosis. The As2O3 treatment also resulted in an increased M phase cell cycle distribution by inducing microtubule polymerization. Two independent death-signaling pathways in cervical cancer cells were activated, one dominated by JNK/p38/GADD45 and one by p53 signals. Further investigation involving assessment of As2O3 on tumor cell growth in mice indicated that As203 also inhibited in vivo tumor growth. As2O3 as an inhibitor of cervical cancer proliferation both in vitro and in vivo suggests a potential clinical application in cervical cancer therapies.     

The apoptotic effect of shikonin on human papillary thyroid carcinoma cells through mitochondrial pathway

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

Se-methylselenocysteine induces apoptosis through caspase activation and Bax cleavage mediated by calpain in SKOV-3 ovarian cancer cells

Se-methylselenocysteine (Se-MSC) is a potent chemopreventive agent in many test systems and has been shown to inhibit tumor promotion and induce apoptosis, but its mechanism of action is still not well understood. The present study was designed to assess the mechanism of Se-MSC on the induction of apoptosis in SKOV-3 ovarian cancer cells. Se-MSC displayed strong inhibitory effects on cell proliferation and viability of SKOV-3 cells in dose and time dependent manners and induced apoptosis. Investigation of the mechanism of Se-MSC-induced apoptosis revealed that treatment with Se-MSC produced morphological features of apoptosis and DNA fragmentation. This was associated with caspase-3 activation and cleavage of poly(ADP-ribose) polymerase and phospholipase C-gamma1 proteins. However, SKOV-3 cells treated with Se-MSC did not demonstrate cytochrome c accumulation in the cytosol during apoptosis induction. Pretreatment of cells with the caspase inhibitors (z-VAD-fmk and DEVD-CHO) prevented Se-MSC-induced apoptosis. These results suggested that Se-MSC induces apoptosis through cytochrome c-independent caspase-3 activation in SKOV-3 cells. In late stage of apoptosis, p18kDa fragment of Bax was generated with the down-regulation of the expressions of survivin, X-linked inhibitor of apoptosis protein, and human inhibitor of apoptosis protein 1 following Se-MSC treatment, suggesting that the modulation of Bax and IAP (inhibitors of apoptosis) family proteins play some role in Se-MSC-mediated apoptosis. Pre-treatments of z-VAD-fmk and the calpain inhibitor, calpeptin inhibited Bax cleavage. These results suggested that Bax cleavage is mediated by calpain, and calpain activation may be a caspase-dependent one. Taken together, the chemopreventive effects of Se-MSC may be related in part to the caspase-3 activation, the down-regulation of IAP family proteins, and Bax cleavage mediated by caspase-dependent calpain activation.     

Sulforaphane induces caspase-mediated apoptosis in cultured PC-3 human prostate cancer cells and retards growth of PC-3 xenografts in vivo

Sulforaphane (SFN), a constituent of cruciferous vegetables, is highly effective in affording protection against chemically induced cancers in animal models. Here, we report that SFN inhibited proliferation of cultured PC-3 human prostate cancer cells by inducing apoptosis that was characterized by appearance of cells with sub-G0/G1 DNA content, formation of cytoplasmic histone associated DNA fragments and cleavage of poly(ADP-ribose)polymerase (PARP). SFN-induced apoptosis was associated with up-regulation of Bax, down-regulation of Bcl-2 and activation of caspases-3, -9 and -8. SFN-induced apoptosis, and cleavage of procaspase-3 and PARP were blocked upon pre-treatment of cells with pan caspase inhibitor z-VADfmk, and specific inhibitors of caspase-9 (z-LEHDfmk) and caspase-8 (z-IETDfmk) suggesting involvement of both caspase-9 and caspase-8 pathways in SFN-induced cell death. Oral administration of SFN (5.6 micro mol, 3 times/week) significantly inhibited growth of PC-3 xenografts in nude mice. For instance, 10 days after starting therapy, the average tumor volumes in control and SFN-treated mice were 170 +/- 13 and 80 +/- 14 mm3, respectively, reflecting a >50% reduction in tumor volume due to SFN administration. To the best of our knowledge, the present study is the first published report to document in vivo anticancer activity of SFN in a tumor xenograft model.