姜黄素对肝癌细胞HepG2的抗癌作用及P21WAF1/CIP1表达的影响

目的：探讨姜黄素对肝癌HepG2细胞抗癌作用及相关周期蛋白依赖激酶抑制因子P21WAF1/CIP1表达的影响。方法：体外培养肝癌HepG2细胞,用MTT法检测姜黄素对HepG2细胞的抑制作用,以RT-PCR方法检测HepG2细胞中P21WAF1/CIP1mRNA的表达,用免疫细胞化学检测其P21WAF1/CIP1蛋白的表达。结果：姜黄素呈时间剂量性抑制HepG2细胞的生长,并显著上调HepG2细胞中P21WAF1/CIP1mRNA和蛋白的表达。结论：姜黄素能抑制HepG2细胞的生长,并上调其中P21WAF1/CIP1的表达。     

白藜芦醇体外对肝癌HepG2细胞分化及P21WAF1/CIP1表达的影响

目的:探讨白藜芦醇(Resvratrol,Res)在体外对肝癌细胞分化及相关周期蛋白依赖激酶抑制因子P21WAF1/CIP1的影响.方法:体外培养肝癌HepG2细胞.用MTT法检白藜芦醇对HepG2细胞的生长抑制作用,用倒置显微镜观察肝癌细胞的形态改变,用放射免疫法检测其AFP分泌.以RT-PCR方法检测HepG2细胞中P21WAF1、CIP1mRNA的表达,用免疫细胞化学检测其P21WAF1、CIP1蛋白的表迭.结果:白藜芦醇呈时间剂量性抑制HepG2细胞株的增殖,使其亚细胞结构趋于正常,AFP分泌量下降,并显著上调HepG2细胞中P21WAF1/CIP1 mRNA和蛋白的表达.结论:白藜芦醇能诱导HepG2细胞在体外向正常肝细胞分化,并上调其P21WAF1/CIP1的表达.     

白藜芦醇体外对肝癌HepG2细胞分化及P21^WAF1/CIP1表达的影响

目的：探讨白藜芦醇（Resvratrol,Res）在体外对肝癌细胞分化及相关周期蛋白依赖激酶抑制因子P21^WAF1/CIP1的影响。方法：体外培养肝癌HepG2细胞,用MTT法检白藜芦醇对HepG2细胞的生长抑制作用,用倒置显微镜观察肝癌细胞的形态改变,用放射免疫法检测其AFP分泌,以RT-PCR方法检测HepG2细胞中P21^WAF1/CIP1mRNA的表达,用免疫细胞化学检测其P21^WAF1/CIP1蛋白的表达。结果：白藜芦醇呈时间剂量性抑制HepG2细胞株的增殖,使其亚细胞结构趋于正常,AFP分泌量下降,并显著上调HepG2细胞中P21^WAF1/CIP1mRNA和蛋白的表达。结论：白藜芦醇能诱导HepG2细胞在体外向正常肝细胞分化,并上调其P21^WAF1/CIP1的表达。     

丙戊酸钠抑制A549细胞生长

目的研究丙戊酸钠对肺癌A549细胞增殖和细胞周期的影响。方法MTT检测生长抑制,流式细胞仪检测细胞周期和凋亡,Western blot检测p21WAF1/CIP1蛋白表达。结果丙戊酸钠以剂量依赖性方式抑制A549细胞生长;丙戊酸钠上调G0/G1期比例,下调S期和G2/M期,不影响细胞凋亡;丙戊酸钠上调p21WAF1/CIP1蛋白表达。结论丙戊酸钠上调p21WAF1/CIP1表达,使细胞阻滞于G0/G1期,抑制A549细胞生长。     

5- 脱氧杂氮胞苷对人肝癌细胞HepG2 增殖及beclin1 表达的影响

目的:观察5-脱氧杂氮胞苷(5-aza-CdR)对HepG2细胞生长抑制及beclin1表达的影响,以探讨其抗肿瘤发生的潜在机制。方法:采用四甲基偶氮唑盐(MTT)法检测5-aza-CdR对HepG2细胞的生长抑制;用相差显微镜观察不同药物浓度下不同时间段的肝癌细胞形态学改变;采用RT-PCR法和Western blot法检测5-Aza-CdR对抑癌基因beclin1的mRNA和蛋白表达的影响。结果:5-aza-CdR可抑制HepG2细胞生长,呈剂量依赖性,并上调beclin1的mRNA和蛋白的表达。结果:显示102.4umol/L5-aza-C-dR作用72小时细胞增殖抑制率最高,可达(84.3±3.31)%,beclin1的mRNA和蛋白表达上调最明显,与对照组相比差异有统计学意义。结论:5-aza-CdR可抑制HepG2细胞增殖,其机制可能是通过恢复某些抑癌基因的表达,上调beclin1的mRNA和蛋白表达。     

乳腺癌中Rho A蛋白表达及其与Cyclin D1和P21WAF1/CIP1蛋白表达的相关性

目的探讨Rho A蛋白在人乳腺癌中的表达情况,Rho A蛋白与临床病理因素的关系,及其与细胞周期蛋白Cyclin D1,细胞周期抑制蛋白 P21 WAF1/CIP1表达的相关性.方法应用免疫组化S-P法,检测64例乳腺癌组织及20例正常乳腺组织中Rho A蛋白、Cyclin D1和P21 WAF1/CIP1蛋白的表达情况.结果 (1)Rho A、 Cyclin D1和P21 WAF1/CIP1蛋白在正常乳腺组织中的表达率分别为5.00%、25.00%、15.00%,在乳腺癌组织中的表达率分别为73.44%、59.38%、48.44%,三者在乳腺癌组织中的阳性表达分别与正常乳腺组织相比,均差异有显著性意义(P< 0.01).(2)Rho A蛋白表达与病理组织分级,淋巴结转移相关(P< 0.05),与患者年龄、肿瘤大小及临床分期无关.(3)RhoA蛋白与P21 WAF1/CIP1蛋白表达呈负相关(χ2=4.548,P<0.05),与Cyclin D1蛋白表达无关.结论乳腺癌患者RhoA蛋白过表达与预后不良有关.RhoA蛋白通过下调P21 WAF1/CIP1蛋白参与细胞周期调节,进而与乳腺癌发展及侵袭转移相关.     

利用RNA干扰抑制p21WAF1/CIP1基因的表达及周期阻滞效应

目的：构建p21WAF1/CIP1基因小干扰RNA（siRNA）的真核表达载体,观察其对p21WAF1/CIP1表达的影响和细胞周期的变化。方法：合成了针对p21WAF1/CIP1基因的siRNA,将其克隆到siRNA表达载体pSliencer2.1-U6neo上,将重组质粒和带FLAG标签的p21WAF1/CIP1共转染293T人胚肾细胞,通过Westernblot检验RNA干扰（RNAi）敲低外源p21WAF1/CIP1的效果;将重组质粒单独转染293T人胚肾细胞,利用p21WAF1/CIP1抗体检测RNAi敲低内源p21WAF1/CIP1的效果;利用流式细胞仪检测敲低后细胞周期的变化。结果：测序证明构建了p21WAF1/CIP1siRNA真核表达载体;Westernblot和流式细胞分析证明,构建的siRNA能有效降低p21WAF1/CIP1基因的表达,并且使G1期细胞数减少14.03%,S期细胞增多13.45%。结论：构建了p21WAF1/CIP1siRNA的真核表达载体,该siRNA能有效抑制p21WAF1/CIP1基因的表达并部分解除了G1期阻滞。     

乙肝病毒x基因致肝细胞癌机理探讨

构建HBx基因真核表达载体, 导入HepG2细胞中, 无血清培养同步化后, Western 杂交检测HepG2-X细胞IGF-ⅠR, PCNA和VEGF表达增强, 但无p21CIP1/WAF1表达. 流式细胞检测细胞周期, HepG-X0细胞70%进入G0～G1期, 而HepG2-X细胞仅56%进入G0～G1期, 与血清培养亲本HepG2细胞几乎相同. HBx基因增强IGF-ⅠR表达, 通过信号通路到细胞核, 同时使PCNA表达增强, p21CIP1/WAF1表达抑制, 推进细胞周期, 使G0～G1细胞明显减少. HBx基因增强VEGF表达, 通过旁分泌作用使血管内皮增生; 以上可能是HBx蛋白致HCC 的机理之一.     

姜黄素联合索拉菲尼对肝癌细胞系HepG-2细胞增殖及自噬的影响

目的:研究姜黄素联合索拉菲尼对肝癌细胞系HepG-2细胞增殖及自噬的影响。方法:体外培养肝癌细胞系HepG-2细胞,用不同浓度姜黄素(0、10、20、30、40、50 mmol/L)、不同浓度索拉菲尼(0、5、10、15、20μmol/L)及两药联合处理肝癌细胞系HepG-2细胞24 h后,用CCK8实验检测细胞存活率。用姜黄素30 mmol/L、索拉菲尼10μmol/L及两药联合处理肝癌细胞系HepG-2细胞24 h后,用荧光定量PCR检测自噬相关信号通路关键蛋白AKT、mTOR及自噬相关蛋白LC3-Ⅱ的mRNA表达情况。结果:姜黄素、索拉菲尼及两药联合对HepG-2细胞均有增殖抑制作用,且呈浓度依赖性。与姜黄素或索拉菲尼单药组相比,姜黄素联合索拉菲尼组能显著抑制肝癌细胞系HepG-2细胞的增殖(P0.001);能显著抑制AKT、mTOR的mRNA表达而增加自噬相关蛋白LC3-Ⅱ的mRNA的表达(P0.001)。结论:姜黄素联合索拉菲尼组抑制肝癌细胞系HepG-2细胞增殖作用较单药组明显增强,两药联合协同诱导肝癌细胞系HepG2细胞产生自噬,其作用机制可能与抑制PI3K/AKT/mTOR信号通路有关。     

S-Equol对高糖培养HepG2细胞胰岛素敏感性及IRS-1表达的影响

目的:研究S型雌马酚(S-Equol,S-Eq)对高糖培养HepG2人肝癌细胞株胰岛素敏感性和胰岛素受体底物(insulin receptor substrate,IRS)-1表达的影响并探讨其可能的分子机制.方法:高糖培养HepG2细胞,1、10、100 μM S-Eq处理细胞后,MTT法检测细胞活力,硫酸蒽酮比色法检测胰岛素刺激细胞糖原合成量,Realtime PCR和Western blot法分别检测IRS-I mRNA及蛋白表达变化.结果:S-Eq对HepG2细胞活力无明显影响,但显著改善高糖培养条件下HepG2细胞胰岛素敏感性,其中10 μM S-Eq+H组胰岛素刺激后细胞糖原合成量上升最为显著(P＜0.01),同时发现,S-Eq能显著上调IRS-1 mRNA和蛋白表达量.结论:S-Eq可能通过调控IRS-1的表达,增强高糖培养HepG2细胞胰岛素敏感性,这可能是S-Eq发挥其抗糖尿病作用的重要理论依据.     

Linkage of Curcumin-Induced Cell Cycle Arrest and Apoptosis by Cyclin-Dependent Kinase Inhibitor p21/WAF1/CIP1

We have recently shown that curcumin induces apoptosis in prostate cancer cells through Bax translocation to mitochondria and caspase activation, and enhances the therapeutic potential of TRAIL. However, the molecular mechanisms by which it causes growth arrest are not well-understood. We studied the molecular mechanism of curcumin-induced cell cycle arrest in prostate cancer androgen-sensitive LNCaP and androgen-insensitive PC-3 cells. Treatment of both cell lines with curcumin resulted in cell cycle arrest at G1/S phase and that this cell cycle arrest is followed by the induction of apoptosis. Curcumin induced the expression of cyclin-dependent kinase (CDK) inhibitors p16/INK4a, p21/WAF1/CIP1 and p27/KIP1, and inhibited the expression of cyclin E and cyclin D1, and hyperphosphorylation of retinoblastoma (Rb) protein. Lactacystin, an inhibitor of 26 proteasome, blocks curcumin-induced down-regulation of cyclin D1 and cyclin E proteins, suggesting their regulation at level of posttranslation. The suppression of cyclin D1 and cyclin E by curcumin may inhibit CDK-mediated phosphorylation of pRb protein. The inhibition of p21/WAF1/CIP1 by siRNA blocks curcumin-induced apoptosis, thus establishing a link between cell cycle and apoptosis. These effects of curcumin result in the proliferation arrest and disruption of cell cycle control leading to apoptosis. Our study suggests that curcumin can be developed as a chemopreventive agent for human prostate cancer.     

Expression of p21WAF1/CIP1 in bladder cancer: relation to schistosomiasis

Cell cycle regulation is mediated in part through expression of the cyclin-dependent kinase inhibitor p21WAF1/CIP1. Loss of p21WAF1/CIP1 expression may, therefore, contribute partially to schistosomal carcinogenesis in the urinary bladder. We compared p21WAF1/CIP1 expression in schistosomal and nonschistosomal bladder cancer to explore possible differences in p21WAF1/CIP1 expression between the two subtypes and the possible association between schistosomiasis and loss of p21WAF1/CIP1 expression. Tumor specimens were obtained from 130 patients who underwent transurethral biopsy or cystectomy. p21WAF1/CIP1 was determined by immunodot blot, Western blot, and enzyme immunoassay (EIA). We validated a highly sensitive quantitative EIA assay for determination of p21WAF1/CIP1 in cell lysates. Precision, analytical recovery, and linearity were all excellent. Our results did not show any correlation between p21WAF1/CIP1 expression and most clinicopathologic variables. Lower expression of p21WAF1/CIP1 was evident in squamous cell carcinoma (SCC) and schistosomal subtype than in transitional cell carcinoma and nonschistosomal tumors. Our data suggest a potential role for p21WAF1/CIP1 alteration in schistosomal carcinogenesis.     

Induction of apoptosis in p53-deficient human hepatoma cell line by wild-type p53 gene transduction: inhibition by antioxidant

We investigated the role of wild-type (wt)-p53 as an inducer of apoptotic cell death in human hepatoma cell lines. Following the retrovirus-mediated transduction of the wt-p53 gene, Hep3B cells lacking the endogenous p53 expression began to die through apoptosis in 4 h. They showed a maximal apoptotic death at 12 h, whereas HepG2 cells expressing endogenous p53 did not. However, the transduction of the wt-p53 gene elicited growth suppression of both Hep3B and HepG2 cells. P21(WAF1/CIP1), a p53-inducible cell cycle inhibitor, was induced, not only in Hep3B cells undergoing apoptosis, but also in HepG2 cells. The kinetics of the p21(WAF1/CIP1) induction, DNA fragmentation, and growth suppression of the Hep3B cells showed that DNA fragmentation and growth suppression progressed rapidly following p21(WAF1/CIP1) accumulation. N-acetyl-cysteine or glutathione, potent antioxidants, strongly inhibited the DNA fragmentation, but did not reduce the elevated level of p21(WAF1/CIP1). These findings suggested that p21(WAF1/CIP1) was not a critical mediator for the execution of p53-mediated apoptosis, although it contributed to the growth inhibition of cells undergoing apoptosis. Furthermore, p53-mediated apoptosis could be repressed by antioxidants.     

Troglitazone suppresses cell growth of myeloid leukemia cell lines by induction of p21WAF1/CIP1 cyclin-dependent kinase inhibitor.

In a human eosinophilic leukemia cell line, EoL-1, cell proliferation was suppressed by 2-day treatment with troglitazone. EoL-1 cells treated with troglitazone were arrested and maintained in the G0/G1 phase in the cell cycle. This suppression correlated with the up-regulation of mRNA for p21WAF1/CIP1 cyclin-dependent kinase (Cdk) inhibitor. The inhibitory effects of troglitazone on cell proliferation and expression of p21 mRNA were observed in a human myelomonocytic cell line, U937, and a human myelomonoblastic cell line, KPB-M15. In addition, in EoL-1 cells, p21 protein was induced by troglitazone treatment and the induction was inhibited by protein synthesis inhibitor, cycloheximide. These data suggest that troglitazone inhibits cell proliferation in myeloid leukemia cell lines at least in part by induction of p21 Cdk inhibitor.