Curcumin down-regulates PCNA, cyclin D1 and Bcl-XL expression in human keratinocyte cell lines

Objective：To evaluate the effects of curcumin on regulating the proliferation,cell cycle distribution,apoptosis and relevant mechanisms in keratinocyte cell lines.Methods：The human immortalized human keratinocyte lines（HaCaT cells） were treated with different doses of curcumin.The effects of curcumin on cell viability were measured by MTT assay,and the cell cycle distribution and apoptosis determined by flow cytometry.The mRNA expression changes of proliferating cell nuclear antigen（PCNA）,cyclin D1 and Bcl-xL were from real-time PCR analysis and the protein levels were detected by Western blotting.Results：Data obtained in the study showed that curcumin could cause significantly inhibitory effect on proliferation in HaCaT cells in a time- and dose-dependent manner.Cell arrest at G1/S phase and significant apoptosis were observed after being treated with curcumin for 24 h.In association with these,the expression of PCNA,cyclin D1 and Bcl-xL were decreased both at mRNA and protein levels for the same treatment.Conclusion：Curcumin can inhibit proliferation,induce cell arrest at G1/S phase and cause apoptosis in HaCaT cells.The decreased expression of PCNA,cyclin D1 and Bcl-xL induced by curcumin contributes to the above effects in vitro.     

Suppression of breast cancer proliferation and induction of apoptosis via AKT and ERK1/2 signal transduction pathways by synthetic polypeptide derived from viral macrophage inflammatory protein II

SDF-1α,a ligand for the chemokine receptor CXCR4,is well known for mediating the migration of breast cancer cells.In a previous study we demonstrated that a synthetic 21-mer peptide antagonist of CXCR4(NT21MP) derived from the viral macrophage inflammatory protein Ⅱ could antagonize tumor growth in vivo by inhibiting cellular proliferation and inducing apoptosis in breast cancer cells.However,the role of SDF-1α in the signaling pathways underlying the proliferation of human breast cancer cells and associated signaling pathways and inhibiting signal pathways of NT21MP remained unclear.The present study investigated the mechanism of NT21MP on anti-tumor in breast cancer in vitro.The effect of NT21MP on the viability of cells was determined by the MTT assay.Annexin V-FITC and PI staining was performed to detect early stage apoptosisin SKBR3 cells treated with SDF-1α and AMD3100 or NT21MP.Western blotting techniques were used to assay the composition of phosphoproteomics and total proteins present in the SKBR3 breast cancer cells.RT-PCR and Western blotting technique were used to detect the effect of NT21MP and AMD3100 on Bcl-2 and Bax expression.The results indicated that SDF-1α prevented apoptosis and promoted the proliferation of SKBR3 human breast cancer cells.As compared with untreated SKBR3 cells,Treatment with SDF-1α significantly increased cell viability,and NT21MP abolished the protective effects of SDF-1α dose-dependently(P<0.05).There was a significant decrease in the percentage of apoptotic cells after SDF-1α treatment as compared with control group(2.7%±0.2% vs.5.7%±0.4%,P<0.05).But pretreatment of SKBR3 cells with NT21MP significantly attenuated the antiapoptotic effects of SDF-1α as compared with SKBR3 cells without NT21MP pretreatment.The proliferative and anti-apoptotic effects of SDF-1α in SKBR3 cells were associated with an increase in AKT and ERK1/2 phosphorylation as well as a decrease in Bax expression and an increase in Bcl-2 expression.These changes in intracellular processes were blocked by NT21MP in a dose-dependent manner(P<0.05).In conclusion,NT21MP efficiently inhibits SDF-1α-induced proliferation and antiapoptosis in SKBR3 cells by reducing the levels of phosphorylated AKT and ERK1/2,as well as decreasing the ratio of expression of Bcl-2 relative to Bax.     

Effects of inotodiol extracts from inonotus obliquus on proliferation cycle and apoptotic gene of human lung adenocarcinoma cell line A549

Objective:To observe the proliferation inhibition,apoptosis,and cell proliferation cycle of human lung carcinoma cell line A549 treated with Inotodiol extracts from Inonotus obliquus and explore the possibility of Inotodiol extracts from Inonotus obliquus as a new tumor chemopreventive drug.Methods:Human lung cancer cell line A549 was treated with different concentrations of Inotodiol,the effects of Inotodiol on cell apoptosis,the expression of Ki-67,Bcl-2,Bax,and p53 and cell cycle were detected by TUNEL assay,immunohistochemistry, and flow cytometry assay respectively.Results:Inotodiol extracts had antiproliferation effect on human lung carcinoma cell line A549.The expression of Ki-67 decreased with the increase of Inotodiol concentration and exposure time(P<0.05),in a dose-dependent and time-dependent manner.The typical characteristics of the apoptosis of A549 cells treated with Inotodiol were observed,and the apoptotic rate of A549 cell at 48 h was the highest by TUNEL assay.Inotodiol arrested A549 cells in the S phase,and apoptotic peak was observed by flow cytometry.Immunocytochemistry indicated that the expression of Bcl-2 protein decreased,while the expression of p53 and Bax proteins increased in A549 cells treated with Inotodiol,compared with the control cells(P<0.05).Conclusion:Inotodiol can inhibit proliferation and induce the apoptosis of A549 cells,and its molecular mechanism may be associated with the up-regulating expression of p53 and bax proteins and down-regulating expression of Bcl-2 protein,which arrested A549 cells in S phase.     

Altered gene expression reveals molecular mechanisms underlying oridonin-induced apoptosis of multiple myeloma LP-1 cells

Objective: To investigate the effect of oridonin on proliferation and invasion of human multiple myeloma LP-1 cells and the underlying mechanism. Methods: LP-1 cells in culture medium in vitro were treated with oridonin at the different concentration. Cell proliferation was measured by Microwave Theory and Techniques (MTT) assay and cell apoptotic rate was detected by flow cytometry. Morphology of cell apoptosis was observed by transmission electron microscope. Expressions of Bax, Bcl-2, Caspase-3, NF-κB as well as I-κB mRNA were detected by real-time PCR. Results: The MTT assays and flow cytometry revealed that oridonin could inhibit the growth of LP-1 cells and cause apoptosis significantly; the suppression was both in time- and dose-dependent manner. Marked morphological changes of cell apoptosis were found under a transmission electron microscope after the cells were treated with oridonin at 25 μmol/L for 24 h. Along with the apoptotic process, Bcl-2, Caspase-3,NF-κB gene expressions were down-regulated (P<0.05). On the contrast, the Bax and I-κB gene expressions were up-regulated (P<0.05). Conclusion: Oridonin could inhibit the proliferation of LP-1 cells via inducing apoptosis. We concluded that oridonin induces apoptosis in LP-1 cells via activation of caspase-3 as well as down-regulation of Bcl-2 and up-regulation of Bax expression. The results suggested that oridonin could induce apoptosis of LP-1 cells through mitochondria- and caspase3-dependent pathways. Meanwhile, the inhibition of NF-κB and the activation of I-κB indicate pro-apoptotic stimuli. In one word, oridonin might be an important potential anti-myeloma reagent.     

Triptolide-induced apoptosis by inactivating nuclear factor-kappa B apoptotic pathway in multiple myeloma <Emphasis Type="Italic">in vitro</Emphasis>

The effect of triptolide on proliferation and apoptosis of human multiple myeloma RPMI-8226 cells in vitro,as well as the roles of nuclear factor-kappa B(NF-κB) and IκBα was investigated.The effect of tritptolide on the growth of RPMI-8226 cells was studied by MTT assay.Apoptosis was detected by Hoechest 33258 staining and Annexin V/PI double staining assay.The expression of NF-κB and IκBα was observed by Western blot and confocal microscopy.The results showed that triptolide inactivated NF-κB apoptotic pathway in human multiple myeloma RPMI-8226 cells.Triptolide at nM range induced proliferation inhibition in a dose-and time-dependent manner and apoptosis in a dose-dependent fashion in RPMI-8226 cells.Besides,we observed the inhibition of NF-κB /p65 in the nuclear fraction was correlated with the increase in the protein expression of IκBα in the cytosol.These results suggested that triptolide might exhibit its strong anti-tumor effects via inactivation of NF-κB/p65 and IκBα.     

Histone deacetylase inhibitor trichostatin A induced caspase- independent apoptosis in human gastric cancer cell

Background Histone deacetylase inhibitors （HDACIs） have been reported to induce apoptosis in cancer cells. The effects of trichostatin A （TSA） on gastric cancer cells have not been well characterized. This study was aimed to explore the effects and mechanisms of TSA on human gastric cancer SGC-7901 cells. Methods The cells were treated with TSA and analyzed by cell proliferation assay, Western blot, TUNEL assay, flow cytometry by fluorescein isothiocyanate （FITC） conjugated with Annexin V and PI staining, immunofluorescence analysis, analysis of subcellular fractionation, gene chips and real time polymerase chain reaction （PCR）. Results TSA could inhibit cell growth and induced apoptosis in gastric cancer SGC-7901 cells through the regulation of apoptosis-related genes, such as Bcl-2, Bax and survivin. Further study indicated that the pan-caspase inhibitor z-VAD-fmk did not inhibit the apoptosis induced by TSA, and we did not observe the cleavage of poly ADP ribose polymerase （PARP） after TSA treatment too. In addition, apoptosis inducing factor （AIF） and EndoG were found to translocate from mitochondria to nucleus in the immunofluorescence assay and the Western analysis of subcellular fractionation confirmed the result of immunofluorescence assay. Conclusions The apoptosis induced by TSA in gastric cancer SGC-7901 cells involves a caspase-independent pathway.     

Study of apoptosis induced by nordihydroguaiaretic acid in human ma-lignant glioma cell line SHG-44

Objective: To investigate the effect and mechanism of nordihydroguaiaretic acid (NDGA) on apop-tosis in human malignant glioma cell line SHG-44. Methods: Cell growth inhibition was measured with MTT assay. Cell apoptosis was observed with light and electron microscopy and TUNEL. Expression of bcl-2 gene was measured with immunohistochemistry, in situ hybridization and image analyses. Results: NDGA at the concentration of 100 μmol/L inhibited the proliferation of SHG-44 cells and induced apoptosis in a time-de-pendent manner. The expression of Bcl-2 protein in SHG-44 cells was decreased in the present of 100 μmol/L NDGA along with the duration of treatment in a negative correlation with the degree of cell apoptosis. The bcl-2 mRNA expressed in SHG-44 cells was reduced after treatment with 100 μmol/L NDGA, apparently consistent with the immunohistochemical results. Conclusion.- NDGA can induce apoptosis of human malig-nant glioma cells probably by down-regulating expression of bcl-2 gene, though the exact mechanism needs further study.     

葡萄籽原花青素对海马细胞氧化损伤和凋亡的影响

目的:观察葡萄籽原花青素(GSP)对大鼠海马细胞氧化损伤的保护作用,及对凋亡相关基因Bcl-2和Bax表达的影响。方法:建立H2O2致海马细胞损伤模型,观察GSP对细胞形态和细胞存活率的影响;并用免疫组化法检测GSP对凋亡相关基因Bcl-2与Bax蛋白表达的影响。结果:1 mmol/L H2O2诱导海马细胞损伤,细胞活力下降(P<0.001),细胞凋亡小体明显增多,细胞中Bcl-2表达下降和Bax表达升高。而GSP可明显减少细胞损伤,上调细胞中Bcl-2的表达,使细胞中Bax表达明显减少,(P<0.01),细胞凋亡明显改善。结论:GSP对H2O2诱导的海马神经细胞凋亡具有保护作用,与GSP可增加Bcl-2表达同时减少Bax表达有关。     

γ-分泌酶抑制剂对正常乳鼠心肌细胞的影响

目的探讨Notch信号特异性阻断剂γ-分泌酶抑制剂（DAPT）对正常乳鼠心肌细胞的影响。方法 SD乳鼠心肌细胞体外分离培养后,与不同浓度DAPT（10μmol/L、5μmol/L、2.5μmol/L、1.25μmol/L、0.625μmol/L、0.3125μmol/L、0.15625μmol/L）孵育24 h,或者与DAPT（5μmol/L）孵育不同时间（1 h、2 h、4 h、8 h、16 h、24 h、48 h）,MTT法测定心肌细胞活力;Western Blotting方法测定心肌细胞Notch1受体胞内区（NICD）和Bcl-2蛋白表达量。结果 DAPT显著抑制正常乳鼠心肌细胞的存活,同时浓度越高、时间越长,其抑制效果越明显;DAPT处理后心肌细胞NICD和Bcl-2表达均降低。结论 DAPT可阻断Notch信号通路,抑制正常乳鼠心肌细胞的增殖,促进细胞凋亡。     

隐丹参酮对人胃癌细胞SGC-7901凋亡的影响及其机制

目的探讨隐丹参酮(CPT)对人胃癌细胞SGC-7901凋亡的影响及其机制。方法用不同浓度的CPT作用于人胃癌细胞SGC-7901,采用四甲基偶氮唑蓝(MTT)法检测细胞增殖的活力;流式细胞术检测细胞凋亡的变化;Real Time RT-PCR法检测细胞凋亡相关蛋白Bax、Bcl-2、p53和p21 mRNA表达的变化;Western blot法检测细胞凋亡相关蛋白Bax、Bcl-2、p53和p21表达的变化。结果 CPT作用于人胃癌细胞SGC-7901 24 h后,可明显抑制细胞生长,诱导细胞发生凋亡;在转录水平上调促细胞凋亡蛋白Bax和p53 mRNA的表达,下调抑制细胞凋亡蛋白Bcl-2 mRNA的表达;在翻译水平上调促细胞凋亡蛋白Bax和p53的表达,下调抑制细胞凋亡蛋白Bcl-2的表达。结论 CPT对人胃癌细胞SGC-7901具有诱导凋亡的作用,其机制可能与线粒体途径相关。     

熊果酸诱导胃癌细胞BGC-823凋亡机制的研究

目的:探讨熊果酸(UA)对胃癌细胞BGC-823增殖抑制和诱导凋亡的作用机制。方法:采用MTT法检测UA对BGC-823细胞的增殖抑制效应;用琼脂糖凝胶电泳观察DNA凋亡片段;流式细胞仪检测UA作用后BGC-823细胞的周期分布和凋亡率;用Fas单克隆抗体检测BGC-823细胞表面Fas的表达;Western blot检测BGC-823细胞Bcl-2的表达及caspase-3和caspase-8的活性。结果:UA对BGC-823细胞具有增殖抑制效应,并呈浓度和时间依赖性。UA作用24 h时半数抑制浓度(IC50)为43.10μmol/L。当UA浓度为50和60μmol/L时,琼脂糖凝胶电泳可呈现DNA凋亡梯带。随着UA浓度从20μmol/L递增到60μmol/L,周期检测发现BGC-823细胞出现亚G1峰逐步增高,S期阻滞增加,G1期下降。细胞内Bcl-2表达下降,caspase-3和caspase-8活性增加。BGC-823细胞表面未发现Fas的表达。结论:UA对BGC-823细胞有较强的增殖抑制和诱导凋亡作用,下调Bcl-2的表达及激活caspase-3、caspase-8可能是其诱导凋亡的机制。     

草苁蓉环烯醚萜苷对二乙基亚硝胺诱发肝癌大鼠细胞凋亡的影响

目的观察二乙基亚硝胺（DEN）诱发大鼠肝癌的病理变化,探讨草苁蓉环烯醚萜苷（IGBR）对细胞凋亡的作用及对p53、Bcl-2蛋白表达的影响。方法132 只Wistar雄性大鼠随机分为对照组、模型对照组、阳性对照组及IGBR 组。除对照组,各组大鼠给予DEN 0.2 g/kg 腹腔注射1 次,而后0.05%的DEN 水溶液用于自由饮水;阳性对照组腹腔注射5- 氟尿嘧啶（5-FU）0.025 g/kg 每周3 次;IGBR 组每日IGBR 0.5 g/kg 灌胃1次。实验第12、20及28周末,分批处死动物,观察肝脏病理变化及细胞凋亡,免疫组织化学法和Western blot检测p53、Bcl-2 的表达。结果与对照组比较,模型对照组肝细胞核大且深染,肝细胞变性、异型增生,有些增生灶可见癌变细胞。凋亡的肝细胞皱缩、核固缩及核仁消失。IGBR组与阳性对照组凋亡指数高于模型对照组,差异有统计学意义（P <0.05）,但两组比较差异无统计学意义（P >0.05）。免疫组织化学结果,p53 和Bcl-2 阳性细胞主要分布于不典型增生灶和癌灶的胞浆中。与模型对照组比较,IGBR 组和阳性对照组p53 表达强度增强,而Bcl-2 表达强度减弱,差异有统计学意义（P <0.05）,IGBR 组和阳性对照组比较,差异无统计学意义（P >0.05）。结论大鼠肝癌发生与细胞凋亡相关,IGBR通过调控p53、Bcl-2 来抑制DEN 诱发大鼠肝癌。     

三硫二苄基抑制头颈部鳞状癌细胞HN30的增殖并诱导其凋亡

目的 探究三硫二苄基（DTS）抑制头颈癌细胞HN30增殖和促进其凋亡的作用机制。方法 通过克隆形成实验检测DTS对不同头颈癌细胞HN30、HN12、SCC25增殖能力的影响,并用MTT实验检测不同浓度DTS对HN30细胞活力的影响;DTS（3、10、30 μmol/L）刺激HN30细胞24 h,经Annexin Ⅴ-FITC/PI双染及JC-1荧光探针染色,采用流式细胞仪检测DTS对HN30 细胞凋亡及线粒体膜电位的影响,并通过免疫印迹实验检测不同浓度 DTS 作用对凋亡相关蛋白 caspase 3、cleavedcaspase-3和Bcl-2表达的影响;通过免疫印迹实验检测HN30细胞在DTS（10 μmol/L）不同作用时间（0、0.5、1、2、4、8、16 h） 下,Akt/p53磷酸化水平的变化。结果 克隆形成实验发现1 μmol/L DTS能够明显抑制头颈癌细胞HN30、HN12及SCC25的增殖。MTT实验发现,与溶剂对照组相比,HN30细胞的细胞活力在DTS作用下呈剂量依赖性降低,在100 μmol/L DTS作用时效果显著（P<0.001）。采用Annexin Ⅴ-FITC/PI双染及JC-1荧光探针染色后,流式细胞术检测发现随着DTS作用浓度增高,HN30细胞的凋亡细胞比例逐渐增高（30 μmol/L DTS作用下,P<0.01）,线粒体膜电位逐渐降低（30 μmol/L DTS作用下, P<0.001）。与溶剂对照组相比,DTS 刺激 24 h 后,HN30 细胞中 cleaved caspase-3 的表达升高（30 μmol/L DTS 作用下,P< 0.01）,Bcl-2的表达降低（30 μmol/L DTS作用下,P<0.001）。与溶剂对照组相比,10 μmol/L DTS刺激HN30细胞16 h后,Akt磷酸化水平被显著抑制（P<0.001）,而p53的磷酸化水平升高（P<0.01）。结论 DTS抑制HN30细胞的增殖,并诱导凋亡,其作用机制可能与Akt/p53信号通路有关。     

二苯乙烯苷上调Bcl-2抑制内皮细胞凋亡

目的研究二苯乙烯苷（TSG）对过氧化氢（H2O2）诱导人脐静脉内皮细胞凋亡的作用,以及对抗凋亡基因Bcl-2表达的影响。方法体外培养人脐静脉内皮细胞,筛选造模内皮细胞凋亡的H2O2浓度,以不同浓度二苯乙烯苷作用24 h。采用MTT法检测细胞生长活力,Hoechst33258染色观察细胞形态,流式细胞仪检测细胞凋亡率,Western-blot检测Bcl-2蛋白的含量。结果过氧化氢能引起内皮细胞损伤,抑制细胞增殖,并且随着浓度增加,细胞生存率逐渐降低。其中300μmol/L H2O2作用后细胞增殖明显受到抑制,Hoechst33258染色可见大量凋亡细胞,流式细胞仪检测出明显的凋亡峰,Bcl-2蛋白的表达量显著减少;加入二苯乙烯苷作用后,随着TSG浓度增加,细胞生存率增加,凋亡率逐渐降低;与H2O2造模组比较,10μmol/L的二苯乙烯苷预处理能够显著提高细胞生存率,抑制细胞的凋亡,并且使Bcl-2表达增加（P〈0.05）。结论二苯乙烯苷能抑制过氧化氢诱导的内皮细胞凋亡,该作用与上调Bcl-2表达有关。     

白英提取液对Hela细胞凋亡及P53和Bcl-2蛋白表达的影响

目的探讨白英提取液对Hela细胞凋亡及野生型P53(wtP53)和Bcl-2蛋白表达的影响。方法采用MTT法检测细胞增殖抑制率,荧光显微镜检测癌细胞形态变化,TUNEL法检测凋亡率,二步法免疫组化检测P53和Bcl-2蛋白表达变化。结果白英提取液能够抑制Hela细胞增殖,且呈剂量依赖性;观察到凋亡细胞典型的形态特征;细胞凋亡率随白英提取液浓度增加而升高;P53蛋白表达显著上升(P<0.01),而Bcl-2蛋白表达明显下降(P<0.01)。结论白英提取液能促进Hela细胞凋亡,其分子机制可能与上调野生型P53蛋白表达和下调Bcl-2蛋白表达有关。