姜黄素上调NF-κB诱导急性早幼粒白血病HL-60细胞凋亡

目的观察姜黄素诱导人急性早幼粒细胞白血病HL-60细胞凋亡的作用,并探讨作用机制。方法用台盼蓝计数观察姜黄素对HL-60细胞生长的抑制作用,AnnexinV-FITC/PI染色流式细胞仪检测细胞凋亡,RT-PCR检测凋亡相关基因mRNA的表达,Western blot检测细胞内NF-κB p65蛋白的表达。结果姜黄素对HL-60细胞生长有抑制作用,并诱导细胞凋亡。姜黄素作用前后HL-60细胞中抗凋亡基因Bcl-2和Bcl-xl表达无明显变化;促凋亡基因Bax和Bid表达增高;P53基因均不表达;NF-κB mRNA和蛋白表达均增高,并呈剂量依赖性。结论姜黄素能诱导HL-60细胞凋亡和上调促凋亡基因Bax和Bid,这可能与NF-κB表达上调有关。     

TIP30 regulates apoptosis-related genes in its apoptotic signal transduction pathway

AIM: To investigate the role of TIP30 in apoptotic signal pathway in hepatoblastoma cells and to provide a basis for TIP30 as a gene therapy candidate in the regression of hepatoblastoma cells. METHODS: Apoptosis of human hepatoblastoma cell lines HepG2 (p53 wild), Hep3B (p53 null) and PLC/RPF/5 (p53 mutant) infected with Ad-TIP30 (bearing a wild type human Tip30 gene) were analyzed and p53, Bax and Bcl-xl expression levels were compared among these cells. MTT assay, DNA fragmentation, in situ 3' end labeling of DNA, annexin-V FITC staining were used to detect cell death and apoptosis in cells at various time intervals subsequent to infection, and to determine whether TIP30 had an effect on the expression levels of some apoptosis-related gene products such as Bax, p53 and Bcl-xl. A similar time course experiment was performed by Western blotting. RESULTS: In MTT assay, the viability of HepG2 cells decreased significantly from 99.7% to 10% and displayed more massive cell death within 5-8 d than Hep3B and PLC/ RPF/5 cells, with their viability decreased from 97.8% to 44.3% and 98.1% to 50.4%, respectively. In annexin-V FITC assay, the percentage of apoptosis cells in HepG2 cells was two to three-fold higher than that in control cells (infected with Ad-GFP), two-fold higher than that in Hep3B cells and 1.4-fold higher than that in PLC/RPF/5 cells 36 h after infection, respectively. Moreover, in HepG2 cells, the p53 began to increase 6-8 h after infection, reaching a maximum level between 8 and 12 h after infection and then dropped. Bax showed a similar increase in the cells as p53 reached the maximum at 8-12 h and subsequently decreased. Interestingly, Bcl-xl protein levels were down regulated during 24 to 36 h after Ad-TIP30 infection. In contrast, ectopic expression of TIP30 in Hep3B and PLC/ RPF/5 cells had no effect on the regulation of Bax expression, but had an effect on Bcl-xl levels. In comparison with HepG2 cells, these data suggested that up-regulation of p53 levels by TIP30 might be a pre-requisite for Bax and Bax/Bcl-xl ratio increase. We hypothesied that TIP30 might regulate Bax gene partly through p53, which sensitizes cells to apoptosis by involving a p53 apoptosis signal transduction pathway. CONCLUSION: TIP30 plays an important role in predisposing hepatoblastoma cells to apoptosis through regulating expression levels of these genes. Ad-TIP30 carrying exogenous TIP30-anti-tumor genes may be regarded as a potential candidate for the treatment of hepatocellular carcinoma.     

Honokiol： A potent chemotherapy candidate for human colorectalcarcinoma

AIM: To investigate the anticancer activity of honokiol on RKO, a human colorectal carcinoma cell line in vitro and in vivo, and to evaluate its possible use in clinic. METHODS: In vitro anticancer activity of honokiol was demonstrated by its induction of apoptosis in tumor cells. We analyzed cell proliferation with MTT assay, cell cycle with flow cytosmeter, DNA fragment with electrophoresis on agarose gels. To test the mechanism of honokiol-induced apoptosis, Western blotting was used to investigate the factors involved in this process. The pharmacokinetics study of honokiol was tested by high phase liquid chromatography. In in vivo study, Balb/c nude mice were incubated with RKO cells. Honokiol was injected intraperitoneally every other day into tumor bearing Balb/c nude mice. RESULTS: Our results showed that honokiol induced apoptosis of RKO cells in a time- and dose-dependent manner. At 5-10 microg/mL for 48 h, honokiol induced apoptosis through activating Caspase cascades. Pharmacokinetics study demonstrated that, honokiol could be absorbed quickly by intraperitoneal injection, and maintained in plasma for more than 10 h. In nude mice bearing RKO-incubated tumor, honokiol displayed anticancer activity by inhibiting tumor growth and prolonging the lifespan of tumor bearing mice. CONCLUSION: With its few toxicity to normal cells and potent anticancer activity in vitro and in vivo, honokiol might be a potential chemotherapy candidate in treating human colorectal carcinoma.     

白藜芦醇对白血病K562细胞增殖、凋亡的影响及机制探讨

目的 探讨白藜芦醇对白血病K562细胞生长的影响及相关作用机制.方法 用不同浓度白藜芦醇作用于K562细胞,CCK-8法观察白藜芦醇对K562细胞生长增殖的影响,AnnexinV-FITC/PI双染法观察白藜芦醇对K562细胞凋亡的影响,PI染色法观察白藜芦醇对K562细胞周期的影响,Western blot法检测K562细胞中的Bcl-2、Bcl-xl、Bax、Cyclin D1蛋白.结果 白藜芦醇作用后的K562细胞的增殖被抑制并且凋亡增加,呈时间-剂量依赖性;同时,凋亡相关分子Bcl-2、Bcl-xl表达下调,Bax表达上调;白藜芦醇作用K562细胞后,G1期细胞增多,S期细胞减少,细胞周期调节蛋白Cyclin D1表达下降.结论 白藜芦醇可抑制K562细胞增殖并诱导其凋亡,其机制可能与下调细胞内Bcl-2、Bcl-xl、Cyclin D1表达并上调Bax的表达有关.     

Resveratrol engages selective apoptotic signals in gastric adenocarcinoma cells

INTRODUCTION Gastric cancer is a major cause of mortality both in developed and underdeveloped countries because currently available chemotherapeutic regimens are not very effective, resulting in high recurrence rates and poor survival. There is strong evidence that the predominant etiological factors contributing to development of gastric cancer are infections with H pylori during early years of life and/or exposure to chemical carcinogens such as those in cigarettes and cured meat[1]. I…     

Helicobacter pylori infection induces apoptosis in gastric cancer cells through the mitochondrial pathway

BACKGROUND AND AIMS: To clarify the role of the mitochondrial pathway in apoptosis induced by H. pylori infection in gastric epithelial cells. METHODS: Cells of a gastric adenocarcinoma cell line SGC-7,901 were co-cultured with H. pylori NCTC 11,637, with or without preincubation with the inhibitors of caspases -3, -8, and -9. Apoptosis was determined by flow cytometry. RT-PCR was used to determine the expression of Bid, Bax, and Bcl-2 mRNA, and Western blotting was used to determine the expression of Bid, Bax, and Bcl-2 proteins, and the activation of caspases -3 and -9. RESULTS: H. pylori directly induced apoptosis in SGC-7,901 cells. Apoptotic indices (AIs) were 6.30 +/- 0.40%, 11.57 +/- 0.78%, 8.63 +/- 0.67%, and 7.22 +/- 0.97%, respectively, at 6, 12, 24, and 48 h after SGC-7,901 cells were co-cultured with H. pylori. H. pylori up-regulated the expression of Bid and Bax at both protein and mRNA levels, and induced a time-dependent activation of caspases -3 and -9. Apoptosis was inhibited significantly by the preincubation of SGC-7,901 cells with the inhibitors of caspase-3 (AIs were 1.72 +/- 0.59%, 2.97 +/- 0.55%, 4.38 +/- 1.56%, and 3.29 +/- 0.83%, respectively, at 6, 12, 24, and 48 h), and caspase -9 (AIs were 2.47 +/- 0.53%, 6.68 +/- 0.47%, 5.97 +/- 0.46%, and 5.43 +/- 0.15%, respectively, at 6, 12, 24, and 48 h). The caspase-8 inhibitor also reduced H. pylori-induced apoptosis by 20%. CONCLUSIONS: H. pylori infection induces apoptosis and the activation of caspases -3 and -9 in gastric cancer cells. Moreover, the caspase inhibitors significantly suppress H. pylori-induced apoptosis. These findings suggest that the mitochondrial pathway may be the major pathway in H. pylori-induced apoptosis in gastric epithelial cells.     

Mechanisms underlying aspirin-mediated growth inhibition and apoptosis induction of cyclooxygenase-2 negative colon cancer cell line SW480

AIM： To investigate the effects of aspirin （acetylsalicylic acid） on proliferation and apoptosis of colorectal cancer cell line SW480 and its mechanism. METHODS： Cyclooxygenase （COX）-2 negative colorectal cancer cell line SW480 was treated with aspirin at concentrations of 2.5 mmol/L, 5.0 mmol/L, 10.0 mmol/L for different periods in v/tro. Anti-proliferation effect of aspirin on SW480 was detected by 3-（4,5-dimeth- ylthiazol-2-yl）-2,5-diphenyltetrazolium bromide （MTT） assay. Cell cycle and apoptosis were observed by flow cytometry （FCM）. Transmission electron microscope （TEM） was used for morphological study. Apoptosis-associated genes were detected by immunohistochemical staining and Western blotting. RESULTS： Aspirin inhibited SW480 proliferation and induced apoptosis in a dose- and time-dependent manner. Treatment with different concentrations of aspirin significantly increased the proportions of cells at the G0/G1 phase and decreased the proportions of cells at the S- and G2/M phases in a concentration-dependent manner. Aspirin not only induced apoptosis but also caused cell necrosis at a high concentration as well. After treatment with aspirin, SW480 cells displayed typically morphological features of apoptosis and necrosis under TEM, and increased the Bcl-2 expression in cells, but the expression of Bax was down regulated. CONCLUSION： Aspirin inhibits proliferation and induces apoptosis of SW480 cells. Its anti-tumor mechanism may arrest cell cycle and shift Bax/Bcl-2 balance in cells.     

Inhibitor of growth 4 induces apoptosis in human lung adenocarcinoma cell line A549 via Bcl-2 family proteins and mitochondria apoptosis pathway

Objective  Inhibitor of growth 4 (ING4) is considered to be a tumor suppressor implicated in several human malignancies by tumor growth inhibition and apoptosis enhancement. In present study, the effects of ING4 on apoptosis and its mechanisms were investigated through the transduction of ING4 cDNA into lung adenocarcinoma cell line A549. Methods  The effects of ING4 on A549 apoptosis were observed by FCM analysis, TUNEL assay, and electron microscopy. Simultaneously, the effects of ING4 on the expression of several apoptosis-related proteins in cell line A549 were evaluated by Western blot analysis. Results  Both Annexin-V FITC analysis by FCM and TUNEL assay revealed more apoptotic cells in A549 cells with exogenous ING4 gene. For electron microscopy, A549 cells with exogenous ING4 gene showed typical morphological changes of apoptosis. The deregulation of Bcl-2 family proteins (Bcl-2, Bcl-xl, Bax, Bak, Bid) and the major apoptotic executioners of mitochondria pathway (Cyt-c, caspase3, PARP) were also observed. Conclusion  Our findings suggest that exogenous ING4 can enhance A549 apoptosis via regulating the expression of Bcl-2 family proteins and the activation of mitochondrial apoptotic pathway. Xiaomei Li, Qingyuan Zhang, and Limin Cai contributed equally to this work.     

斑蝥素诱导人胰腺癌细胞凋亡的实验研究

目的 探讨斑蝥素（Cantharidin）对人胰腺癌细胞凋亡的影响及其作用机制。方法采用MTT法观察斑蝥素对人胰腺癌细胞株SW1990细胞增殖的抑制作用。采用Hoechst33258染色、TUNNEL染色、流式细胞术检测细胞凋亡改变，并以RT—PCR和Westernblot检测凋亡调节基因p53和Bcl-2、Bax的表达。结果 5mol／L斑蝥素能明显抑制人胰腺癌SW1990细胞的生长，呈现凋亡特征。RT—PCR和Westernblot检测可见Bax、p53基因表达显著增加，而Bcl—2基因表达减少。结论 斑蝥素能诱导人胰腺癌细胞凋亡，其作用可能与上调p53、Bax基因和下调Bcl-2基因有关。     

弓形虫ROP16蛋白对人乳腺癌MCF-7细胞增殖、周期和凋亡的影响

目的 探讨弓形虫Ⅰ型(RH)ROP16蛋白在人乳腺癌MCF-7细胞增殖、周期及凋亡方面的作用。方法 以空载体(MCF-7-HBLV)和过表达ROP16蛋白的慢病毒(HBLV-RH ROP16)分别感染MCF-7细胞,嘌呤霉素筛选出稳定表达ROP16的细胞株,Real time PCR、Western blot法检测MCF-7细胞中ROP16 mRNA和蛋白表达水平。CCK-8和流式细胞术检测细胞增殖、周期和凋亡。Western blot法检测细胞周期及凋亡相关蛋白表达。结果 相比MCF-7-HBLV(空载体组)和MCF-7细胞组(对照组),MCF-7-RH ROP16细胞组中ROP16 mRNA和蛋白表达升高;细胞增殖率降低(P<0.01);S期细胞比例、细胞凋亡率升高(P<0.01)。促凋亡因子Bax、P53、Caspase-9、Caspase-3及细胞周期蛋白依赖激酶抑制因子P21表达增高(P<0.01);抗凋亡蛋白Bcl-2及细胞周期蛋白A1(CyclinA1)、周期蛋白依赖性激酶2(CDK2)的表达均下降(P<0.01)。结论 弓形虫Ⅰ型(RH)ROP1...     

Antiproliferation effects of oridonin on HPB-ALL cells and its mechanisms of action

Oridonin, an ent-kaurane diterpenoid derived from the herbal Rabdosia rubescens, has been recently reported to have antitumor effects on a large variety of cancer cells. The present study was undertaken to investigate the in vitro antiproliferation and apoptosis inducing effects of oridonin on HPB-ALL cell lines and its mechanisms of action. HPB-ALL cells in culture medium in vitro were treated with different concentrations of oridonin (16-56 micromol/L). MTT assay was used to detect the cell growth inhibitory rate, and the cell viability was assessed by the trypan blue dye-exclusion method. Cell apoptosis and the mitochondrial membrane potential (delta psi m) were investigated by flow cytometry (FCM), Hoechst 33258 staining, and DNA fragmentation analysis. The expression of caspase-3 and different apoptosis modulators, including Fas and Bcl-2 family members, was analyzed by Western blotting. The results revealed that oridonin could significantly inhibit the growth of HPB-ALL cells and cause apoptosis, and the suppression was both time- and dose-dependent. After treatment with oridonin for 48 hr, the percentage of disruption of delta psi m gradually increased in a dose-dependent manner along with marked changes of cell apoptosis, and necrotic cells increased remarkably after the cells were treated with oridonin for 72 hr; Western blotting showed cleavage of the caspase-3 zymogen protein (32 kDa) with the appearance of its 20-kDa subunit when apoptosis occurred; expression of Bcl-2 and Bcl-XL was downregulated remarkably while expression of Bax and Bid was upregulated concurrently after the cells were treated with oridonin for 24 hr. Of note, the expressions of Fas and other Bcl-2 family members including Bak and Bad remained constant before and after apoptosis occurred. We therefore conclude that oridonin has significant antiproliferation effects on HPB-ALL cells by induction of apoptosis as well as directly causing cell necrosis and that oridonin-induced apoptosis on HPB-ALL cells is mainly related to the disruption of delta psi m and activation of caspase-3 as well as downregulation of anti-apoptotic protein Bcl-2, Bcl-XL, and upregulation of pro-apoptotic proteins Bax and Bid. The results indicate that oridonin may serve as a potential antileukemia reagent.     

Early apoptosis and cell death induced by ATX-S10Na ( Ⅱ)-mediated photodynamic therapy are Bax- and p53-dependent in human colon cancer cells

AIM: To investigate the roles of Bax and p53 proteins in photosensitivity of human colon cancer cells by using lysosome-localizing photosensitizer, ATX-S10Na (Ⅱ).METHODS: HCT116 human colon cancer cells and Bax-null or p53-null isogenic derivatives were irradiated with a diode laser. Early apoptosis and cell death in response to photodynamic therapy were determined by MTT assays, annexin V assays, transmission electron microscopy assays, caspase assays and western blotting.RESULTS: Induction of early apoptosis and cell death was Bax- and p53-dependent. Bax and p53 were required for caspase-dependent apoptosis. The levels of anti-apoptotic Bcl-2 family proteins, Bcl-2 and Bcl-XL,were decreased in Bax- and p53-independent manner.CONCLUSION: Our results indicate that early apoptosis and cell death of human colon cancer cells induced by photodynamic therapy with lysosome-localizingphotosensitizer ATX-S10Na (Ⅱ) are mediated by p53-Bax network and Iow levels of Bcl-2 and Bcl-XL proteins.Our results might help in formulating new therapeutic approaches in photedynamic therapy.     

Mutant p53 protein, Bcl-2/Bax ratios and apoptosis in paediatric acute lymphoblastic leukaemia

PURPOSE: The Bcl-2 family of proteins regulates a late step in the apoptosis pathway. Bcl-2 protein is believed to be involved in imparting resistance to programmed cell death or apoptosis induced by chemotherapeutic agents and radiation. The anti-apoptotic function of the Bcl-2 protein appears to be modulated by its ability to heterodimerize with other members of the gene family, predominantly Bax, a protein favouring induction of apoptosis. Susceptibility to undergoing apoptosis may, therefore, be dependent on the ratio between Bcl-2 and Bax. Both Bax and Bcl-2 are regulated by the tumour-suppressor protein p53. The present study therefore aims to study the significance of the Bcl-2:Bax ratio, p53 expression and apoptosis in paediatric acute lymphoblastic leukaemia (ALL). METHODS: Expression of Bax, Bcl-2 and p53 was determined by immunocytochemistry, and apoptosis was evaluated by an enzymatic end-labelling technique using biotin-dUTP and further confirmed by annexin binding. The presence of mutant p53 was determined using a mutant-p53-specific enzyme-linked immunosorbent assay (ELISA). RESULTS: A total of 32 cases and 20 controls were evaluated. Bcl-2 was found to be expressed in 22/32 of the ALL cases. Pretreatment (spontaneous) apoptosis was observed in 23/32 cases. The mean pretreatment apoptotic index was 11.34 +/- 2.04% with a median value of 7.5%. CONCLUSIONS: There was a positive correlation between apoptosis and Bax expression (r = 0.5044; P = 0.0038). There was good correlation between the immunoreactivity of p53 and detection of mutant p53 by ELISA (r = 0.4605; P = 0.0079). The apoptosis index showed a negative borderline correlation to the expression of Bcl-2 protein (r = -0.3181; P = 0.076). There was an inverse correlation between extent of apoptosis and the presence of mutant p53 protein (r = -0.4732; P = 0.006). p53 protein expression also showed a correlation with both Bcl-2 (r = 0.4647; P = 0.007) and Bax (r = 0.4128; P = 0.018). The Bcl-2/Bax ratio, however, showed no significant correlation with apoptosis (r = -0.3131; P = 0.08) or with p53 expression. No significant association was evident between clinical and laboratory parameters with the Bcl-2/Bax protein expression except lymphadenopathy (r = 0.5774; P = 0.03). However, Bax expression showed a borderline correlation with the immediate tumour response to chemotherapy (r = -0.338; P = 0.0628). These patients are being followed-up to look for any association between clinical outcome, Bcl-2/Bax ratio and apoptosis.     

Exogenous phosphatidylethanolamine induces apoptosis of human hepatoma HepG2 cells via the bcl-2/bax pathway

AIM： To investigate the signaling pathways implicated in phosphatidylethanolamine （PE）-induced apoptosis of human hepatoma HepG2 cells. METHODS： Inhibitory effects of PE on human hepatoma HepG2 cells were detected by 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide （MTT） assay. Cell cycle, apoptosis and mitochondrial transmembrane potential （△ψm） were analyzed by flow cytometry. Immunocytochemical assay and Western blotting were used to examine Bcl-2, Bax and caspase-3 protein levels in HepG2 cells treated with PE. RESULTS： PE inhibited the growth of HepG2 cells in a dose- and time- dependent manner. It did not affect the cell cycle, but induced apoptosis. PE significantly decreased △ψm at 0.25, 0.5 and 1 mmol/L, respectively, suggesting that PE induces cell apoptosis by decreasing the mitochondrial transmembrane potential. The Bcl-2 expression level induced by different concentrations of PE was lower than that in control groups. However, the Bax expression level induced by PE was higher than that in the control group. Meanwhile, PE increased the caspase-3 expression in a dose- and time-dependent manner. CONCLUSION： Exogenous PE induces apoptosis of human hepatoma HepG2 cells via the bcl-2/bax pathway.     

Antitumor bioactivity of adenovirus-mediated p27mt in colorectal cancer cell line SW480

AIM： To explore the antitumor bioactivity of adenovirusmediated mutant type p27^kip1 gene in a colorectal cancer cell line SW480. METHODS： We constructed recombinant adenovirus vector expressing a mutant type p27^kip1 gene （ad- p27mt）, with mutation of Thr-187/Pro-188 （ACGCCC） to Met-187/Ile-188 （ATGATC）, and transduced into SW480 cells. Then we detected expression of p27, Bcl-2 and Bax protein in the transductants by Western blotting, cell cycle of transductants by a digital flow cytometric system, migrating potential with Boyden Chamber and SW480 tumor cell growth inhibition in vitro and in vivo. RESULTS： We found that a recombinant adenovirus vector of expressing ad-p27mt, with mutation of Thr-187/Pro-188 （ACGCCC） to Met-187/Ile-188 （ATGATC） has potent inhibition of SW480 tumor cell growth in vitro and in vivo. Furthermore, ad-p27mt induced cell apoptosis via regulating bax and bcl-2 expressions, and G1/S arrest in SW480 cells and inhibited cell migration. CONCLUSION： ad-p27mt has a strong anti-tumor bioactivity and has the potential to develop into new therapeutic agents for colorectal cancer.     

Early apoptosis and cell death induced by ATX-S10Na （ Ⅱ ）-mediated photodynamic therapy are Bax- and p53-dependent in human colon cancer cells

AIM： To investigate the roles of Bax and p53 proteins in photosensitivity of human colon cancer cells by using lysosome-localizing photosensitizer, ATX-S10Na （Ⅱ）. METHODS： HCT116 human colon cancer cells and Bax-null or p53-null isogenic derivatives were irradiated with a diode laser. Early apoptosis and cell death in response to photodynamic therapy were determined by MTT assays, annexin Ⅴ assays, transmission electron microscopy assays, caspase assays and western blotting. RESULTS： Induction of early apoptosis and cell death was Bax- and p53-dependent. Bax and p53 were required for caspase-dependent apoptosis. The levels of anti-apoptotic Bcl-2 family proteins, Bcl-2 and Bcl-xL, were decreased in Bax- and p53-independent manner. CONCLUSION： Our results indicate that eady apoptosis and cell death of human colon cancer cells induced by photodynamic therapy with lysosome-localizing photosensitizer ATX-S10Na （Ⅱ） are mediated by p53- Bax network and low levels of Bcl-2 and Bcl-xL proteins. Our results might help in formulating new therapeutic approaches in photodynamic therapy.     

Apoptotic pathway induced by diallyl trisulfide in pancreatic cancer cells

AIM:To investigate the effects of diallyl trisulfide(DATS),a garlic-derived organosulfur compound,in pancreatic cancer cells.METHODS:Human pancreatic cancer cells with wildtype p53 gene(Capan-2)and normal pancreatic epithelial cells(H6C7)were cultured in RPMI1640.DATS was prepared at a concentration of 100μmol/L.Cell viability was determined via the methyl thiazolyl tetrazolium assay.Apoptotic cells were detected by TUNEL assay.Cell cycle analysis was performed using flow cytometry.Protein expression was determined by Western blot.Bax and Bcl-2 expression was detected by immunofluorescence.Apoptosis genes and cell cycle were assessed by quantitative real-time polymerase chain reaction.RESULTS:DATS suppressed the viability of cultured human pancreatic cancer cells(Capan-2)by increasing the proportion of cells in the G2/M phase and induced apoptotic cell death.Western blot analysis indicated that DATS enhanced the expression of Fas,p21,p53and cyclin B1,but downregulated the expression of Akt,cyclin D1,MDM2 and Bcl-2.DATS induced cell cycle inhibition which was correlated with elevated levels of cyclin B1 and p21,and reduced levels of cyclin D1 in Capan-2 cells and H6C7 cells.DATS-induced apoptosis was markedly elevated in Capan-2 cells compared with H6C7 cells,and this was correlated with elevated levels of cyclin B1 and p53,and reduced levels of Bcl-2.DATS-induced apoptosis was correlated with downregulation of Bcl-2,Akt and cyclin D1 protein levels,and up-regulation of Bax,Fas,p53 and cyclin B protein levels in Capan-2 cells.CONCLUSION:DATS induces apoptosis of pancreatic cancer cells(Capan-2)and non-tumorigenic pancreatic ductal epithelial cells(H6C7).     

Involvement of p38 mitogen‐activated protein kinase pathway in honokiol‐induced apoptosis in a human hepatoma cell line (hepG2)

Background: Honokiol has been known to have antitumour activity. This study was conducted to evaluate the antiproliferative potential of honokiol against the hepG2 heptocellular cell line and its mechanism of action. Methods: hepG2 cells were treated with honokiol of 0–40 μg/ml concentration. The cytotoxic effect of honokiol was determined by a 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay. The apoptosis was evaluated by flow cytometry. Western blots were used to analyse the expression of various proteins (procaspase‐9, procaspase‐3, cleaved caspase‐3, cytochrome c, Bcl‐2, Bax, Bad, Bcl‐X_L and p38). Results: Honokiol induced apoptosis with a decreased expression of procaspase‐3 and ‐9 and an increased expression of active caspase‐3. Exposure of hepG2 cells to honokiol resulted in the downregulation of Bcl‐X_L and Bcl‐2 expression and the release of mitochondrial cytochrome c to the cytosol. In addition, honokiol activated the p38 mitogen‐activated protein kinase (MAPK) pathway, and the inhibition of this pathway by SB203580 reduced honokiol‐induced apoptosis and activation of caspase‐3. Conclusion: Honokiol induces apoptosis of hepG2 human hepatocellular carcinoma cells through activation of the p38 MAPK pathway, and, in turn, activation of caspase‐3.     

Gli-1 siRNA induced apoptosis in Huh7 cells

AIM： To investigate the effects of Gli-1 small interference RNA （siRNA） on Huh7 cells, and the change of Bcl-2 expression in Huh7 cells. METHODS： Human hepatocellular carcinoma cells Huh7 were used. Cell viability was analyzed by 3-（4, 5-Dimethylthiazol-2-yl）-2, 5-diphenyl tetrazolium bromide （MTT） assay. The expressions of Gli-1 and Bcl-2 family members were detected by RT-PCR and Western blot. Apoptosis was detected by Flow cytometry using propidium iodide, measured by Hoechst 33258 staining using Advanced Fluorescence Microscopy and caspase-3 enzymatic assay. Cell growth was analyzed after treatment with Gli-1 siRNA and 5-fluorouracil （5-Fu）. RESULTS： Inhibition of Gli-1 mRNA in Huh7 cells through Gli-1 siRNA reduced cell viability. Gli-1 siRNA treatment also induced apoptosis by three criteria, increase in the sub-G1 cell cycle fraction, nuclear condensation, a morphologic change typical of apoptosis, and activation of caspase-3. Gli-1 siRNA was also able to down-regulate Bcl-2. However, Gli-1 siRNA resulted in no significant changes in Bcl-xl, Bax, Bad, and Bid. Furthermore, Gli-1 siRNA increased the cytotoxic effect of 5-Fu on Huh7 cell. CONCLUSION： Down-regulation of Bcl-2 plays an important role in apoptosis induced by Gli-1 siRNA in HCC cells. Combination Gli-1 siRNA with chemotherapeutic drug could represent a more promising strategy against HCC. The effects of the strategies need further investigation in vivo and may have potential clinical application.