Involvement of programmed cell death 4 in transforming growth factor-beta1-induced apoptosis in human hepatocellular carcinoma

The programmed cell death 4 (PDCD4) gene was originally identified as a tumor-related gene in humans and acts as a tumor-suppressor in mouse epidermal carcinoma cells. However, its function and regulatory mechanisms of expression in human cancer remain to be elucidated. We therefore investigated the expression of PDCD4 in human hepatocellular carcinoma (HCC) and the role of PDCD4 in human HCC cells. Downregulation of PDCD4 protein was observed in all HCC tissues tested compared with corresponding noncancerous liver, as revealed by Western blotting or immunohistochemical staining. Human HCC cell line, Huh7, transfected with PDCD4 cDNA showed nuclear fragmentation and DNA laddering characteristic of apoptotic cells associated with mitochondrial changes and caspase activation. Transforming growth factor-beta1 (TGF-beta1) treatment of Huh7 cells resulted in increased PDCD4 expression and occurrence of apoptosis, also concomitant with mitochondrial events and caspase activation. Transfection of Smad7, a known antagonist to TGF-beta1 signaling, protected cells from TGF-beta1-mediated apoptosis and suppressed TGF-beta1-induced PDCD4 expression. Moreover, antisense PDCD4 transfectants were resistant to apoptosis induced by TGF-beta1. In conclusion, these data suggest that PDCD4 is a proapoptotic molecule involved in TGF-beta1-induced apoptosis in human HCC cells, and a possible tumor suppressor in hepatocarcinogenesis.     

野生型p53对SMMC-7721细胞中POLD1基因的影响

目的探讨野生型p53基因表达对人肝癌细胞SMMC-7721中POLD1基因的影响。方法设计并构建p53特异性小干扰shRNA绿色荧光真核表达质粒（p53-siRNA）和表达EGFP-p53融合蛋白的p53绿色荧光真核增强表达质粒（pEGFP-p53）,通过稳定转染,将表达pEGFP-p53重组质粒、p53-siRNA转染入SMMC-7721细胞;经G418筛选,获得稳定细胞系7721-p53、7721-p53RNAi。通过RT-PCR检测转染后p53、POLD1的mRNA。结果在人肝癌细胞SMMC-7721中,野生型p53高表达组能够抑制POLD1的基因转录（P〈0.001）;而低表达组能够促进POLD1的基因转录（P〈0.001）。结论在人肝癌细胞SMMC-7721中,p53能够调控POLD1的基因转录。     

可溶性肿瘤坏死因子相关凋亡诱导配体诱导肝癌细胞凋亡的研究

方法 采用原位杂交方法检测肝癌组织、肝癌细胞株以及正常肝组织中TRAILR的表达。采用不同浓度TRAIL蛋白处理肝癌细胞株Hep2和SMMC7721,应用流式细胞仪和原位末端标记,观察经药物处理前后该细胞株的凋亡发生率。结果 60例肝癌组织及20例正常肝组织均表达死亡受体DR5和DR4,但肝癌组织DR表达量显著强于正常肝组织。54例(90．0％)肝癌组织不表达诱捕受体DcR1,25例(41．7％)肝癌组织不表达DcR2,而20例正常肝组织均表达DcR。肝癌组织中DR的高表达及DcR的低表达,不同于正常肝组织中DR的低表达及DcR的高表达,两者间差异有显著性。两种肝癌细胞株中均可检测到DR5、DR4、DcR2的表达,但DcR1表达缺失。肝癌组织中DR的表达与肿瘤的分化、肿瘤分期有关,低分化的肿瘤DR表达减少(P＜0．01),Ⅲ、Ⅳ期肿瘤DR表达显著低于I、Ⅱ期(P＜0．05)。DR表达与患者的性别、年龄、HBsAg阳性与否、AFP水平、肿瘤大小以及是否转移无关。经TRAIL(100ng/ml)处理24h,肝癌细胞凋亡发生率约10％,而Jurkat细胞凋亡率达70％以上,胆管癌细胞QBC939凋亡发生率约50％。结论 肝细胞肝癌普遍存在TRAILR的表达,并存在受体类型的表达差异。但单一的TRAIL治疗只能有限的诱导肝癌细胞HepG2、SMMC7721发生凋亡,HCC对TRAIL诱导的凋亡存在耐药现象。     

miR-223-3p 通过靶向RAC1 调控肝细胞癌SMMC-7721 细胞的增殖和凋亡

目的：探讨miR-223-3p 通过调控Ras 相关C3 肉毒素底物1（Ras-related C3 botulinum toxin substrate 1，RAC1）对肝细胞癌（hepatocellular carcinoma，HCC）细胞增殖和凋亡的影响及其可能的作用机制。方法：选用2016 年8 月至2018 年8 月吉林市中心医院手术切除的30 例HCC 组织及其癌旁组织标本和人HCC 细胞系SMMC-7721、Bel-7402、HepG2 及人正常肝细胞QSG-7701，用qPCR检测HCC组织和细胞系中miR-223-3p的表达水平。分别将miR-223-3p mimics、miR-223-3p inhibitor 和siRAC1转染至SMMC-7721 细胞，通过CCK-8、克隆形成实验和Annexin V-FITC/PI 染色流式细胞术检测SMMC-7721 细胞的增殖、克隆形成和凋亡水平。用双荧光素酶报告基因实验检测miR-223-3p 与RAC1 的靶向关系，Western blotting 检测细胞中RAC1 蛋白的表达水平。结果：miR-223-3p 在HCC组织的表达水平显著低于癌旁组织（P<0.01），其表达水平与肿瘤大小、TNM分期及肿瘤分化病理特征相关（P<0.05 或P<0.01）；miR-223-3p 在HCC细胞系表达水平显著低于QSG-7701 细胞（均P<0.01），以在SMMC-7721细胞中表达水平最低。双荧光素酶报告基因实验证实RAC1 是miR-223-3p 靶基因，miR-223-3p 靶向负调控RAC1 的表达。转染miR-223-3p mimics 显著抑制SMMC-7721 细胞的增殖和克隆形成能力（P<0.05 或P<0.01），并促进细胞凋亡（P<0.01）；转染miR-223-3p inhibtor 则逆转miR-223-3p mimics 对细胞的抑制作用。结论：过表达miR-223-3p 抑制HCC细胞增殖和克隆形成能力并促进细胞凋亡，其机制可能与靶向下调RAC1表达有关。     

人剪切修复基因XPD转染对人肝癌细胞SMMC-7721的生物学影响

目的 将人剪切修复基因XPD稳定转染人SMMC-7721肝癌细胞,观察转染后细胞内野生型p53、XPD、周期素依赖性蛋白激酶(CDK)7、c-myc等基因表达的变化以及对细胞生长的影响,探讨野生型XPD基因与p53、CDK7、c-myc的相互作用及细胞凋亡机制.方法 将表达绿色荧光蛋白并含有人类全长野生型XPD的pEGFP-N2-XPD重组体质粒稳定转染人SMMC-7721肝癌细胞中,选择培养基筛选单克隆稳定转染重组质粒的人SMMC-7721肝癌细胞(SMMC-7721-pEGFP-N2-XPD)和稳定转染空载质粒的人SMMC-7721肝癌细胞(SMMC.7721-pEGFP-N2),并将人SMMC-7721肝癌细胞作为空白对照,利用荧光显微镜观测绿色荧光蛋白表达,用逆转录-聚合酶链反应(RT-PCR)、Westem blot法检测转染XPD基因后细胞内XPD、p53、CDK7、c-myc的表达量变化,并用细胞增殖力检测(MTT)法及流式细胞仪分别检测细胞增殖及凋亡和细胞周期变化.结果 ①免疫荧光显微镜下,SMMC.7721.pEGFP.N2.XPD和SMMC-7721-pEGFP-N2细胞中观察到绿色荧光蛋白表达,说明pEGFP-N2-XPD重组质粒和pEGFP-N2空载质粒成功转染.②RT-PCR检测:SMMC-7721-pEGFP-N2-XPD中p53 mRNA、XPD mR-NA表达量与SMMC-7721-pEGFP-N2和SMMC-7721相比均明显增高(P<0.01),CDK7 mRNA、c-myc mRNA在SMMC-7721-pEGFP-N2-XPD的表达量比两对照组明显降低(P<0.01),而两对照组各个基因的表达没有明显差异(P>0.05).③Western blot检测:SMMC-7721-pEGFP-N2-XPD细胞的p53、XPD蛋白表达最较两对照组升高(P<0.01),CDK7、c-myc的蛋白相对表达量比两对照组降低(P<0.01),两对照组差异没有统计学意义(P>0.05).④M1Tr检测:SMMC-7721-pEGFP-N2-XPD的细胞增殖力较对照组减弱(P<0.05),两对照组筹异没有统计学意义(P>0.05).⑤流式细胞仪检测:SMMC-7721-pEGFP-N2-XPD细胞进入s期出现障碍,停滞在G1期的细胞增多.结论 将XPD成功稳定转染到人SMMC-7721肝癌细胞中,XPD、p53在转录和蛋白水平的表达明显升高,CDK7、c-myc表达明显降低,野生型XPD基因的过表达可能抑制CDK7、c-myc表达,改变细胞周期,并促进p53抑制肝癌细胞增长,促进细胞凋亡.     

Effects of RNAi-mediated Smad4 silencing on growth and apoptosis of human rhabdomyosarcoma cells

Transforming growth factor-beta (TGF-beta) signals through membrane-bound heteromeric serine/threonine kinase receptors. Upon ligand binding, TGF-beta activates intracellular Smad proteins and regulates proliferation and apoptosis in various cell types. To demonstrate the effects of TGF-beta/Smad signal on growth and apoptosis of human embryonal rhabdomyosarcoma (RMS) cells, a strategy of RNAi-mediated 'gene silencing' of Smad4 was used to interrupt endogenous TGF-beta/Smad signaling in an RMS cell line, RD, and the regulation of exogenous TGF-beta1 to growth and apoptosis of the cells was also determined. Physiologically, TGF-beta/Smad signaling was essential for the normal growth of RD. The interruption of endogenous TGF-beta/Smad signaling by RNAi significantly suppressed the growth of RD cells and dramatically induced apoptosis of RD cells. Exogenous TGF-beta1 also inhibited the growth of RD cells, but had no effect on apoptosis. It also partially counteracted the growth inhibition and apoptosis induced by Smad4 silencing in RD cells. These findings provide a new insight into how TGF-beta/Smad signaling regulates the growth and apoptosis of cancer cells. Moreover, as a powerful tool, shRNA interference suppresses endogenous Smad4 gene expression and subsequently modulates cell growth and apoptosis, which may provide a novel basis for the development of rational intervention strategies in RMS therapy.     

Oncolytic adenovirus-mediated E1A gene therapy induces tumor-cell apoptosis and reduces tumor angiogenesis leading to inhibition of hepatocellular carcinoma growth in animal model

Oncolytic adenovirus (rAd)-mediated E1A gene therapy of cancer has become a novel therapeutic modality. In this study, we constructed a recombinant oncolytic adenovirus (rAd-E1A) expressing the tumor suppressor E1A gene. We demonstrated that the rAd-E1A replicated in HepG2 and SMMC-7721 human hepatocellular carcinoma (HCC) cells but attenuated in the normal liver cell line HL-7702. It induced HCC cell apoptosis through upregulation of apoptosis-associated Bax, caspase-3, and Fas and downregulation of survivin and Bcl-2 in a p53-dependent pathway. It also downregulated the expression of angiogenesis- associated vascular endothelial growth factor (VEGF) and CD34 genes and reduced tumor vessel formation and angiogenesis. In mice bearing SMMC-7721 tumors, intratumoral injections of rAd- E1A significantly inhibited HCC growth. Therefore, the oncolytic adenovirus-mediated E1A gene therapy may be a useful therapeutic approach for HCC treatment.     

MiR 142 5p通过靶向IGF2BP3调控多柔比星诱导的肝癌细胞凋亡

目的:探讨miR-142-5p对多柔比星诱导的原发性肝细胞癌(hepatocellular carcinoma,HCC)细胞凋亡的影响及其作用机制.方法:收集广西医科大学附属肿瘤医院88例HCC患者手术切除的癌组织及癌旁组织(距癌灶组织边缘2～5cm)标本.采用实时荧光定量PCR检测人HCC组织和癌旁组织、人正常肝细胞以及HCC细胞系中miR-142-5p的表达量.向HCC细胞SMMC-7721中转染miR-142-5p mimics,流式细胞术检测过表达miR-142-5p后SMMC-7721细胞在多柔比星(doxorubicin)(1 μg/ml)诱导下凋亡的变化;生物信息学方法预测miR-142-5p可靶向结合胰岛素样生长因子2 mRNA结合蛋白3(in-sulin-like growth factor 2 mRNA-binding protein 3,IGF2BP3)基因,并采用荧光素酶报告基因实验进行验证.采用实时荧光定量PCR及Western blotting检测过表达miR-142-5p的SMMC-7721细胞中IGF2BP3的mRNA及蛋白表达情况.结果:与癌旁组织和正常肝细胞相比,HCC组织(-6.91±2.61vs-11.59±2.59,P＜0.01)和多种HCC细胞系中miR-142-5p呈明显低表达(均P＜0.01);过表达miR-142-5p可显著促进多柔比星诱导的HCC细胞SMMC-7721的凋亡[(49.40±3.47)％ vs (19.50±1.74)％,P＜0.01];过表达miR-142-5p可明显降低HCC细胞中IGF2BP3的mRNA及蛋白表达水平(P＜0.01),敲减IGF2BP3表达可进一步促进多柔比星诱导的SMMC-7721细胞的凋亡(P＜0.01).荧光素酶报告基因实验结果显示,miR-142-5p能够抑制IGF2BP3的3'UTR荧光素酶报告基因的活性.结论:miR-142-5p在HCC组织标本和体外培养细胞系中的表达水平均显著降低,转染miR-142-5p mimics后能够促进多柔比星诱导的HCC细胞的凋亡,其机制可能与miR-142-5p靶向作用IGF2 BP3从而促进HCC细胞凋亡有关.     

RNA干扰技术靶向hTERT基因治疗肝癌的实验研究

背景与目的：RNA干扰(RNA interference,RNAi)是由双链RNA介导的、在转录后mRNA水平关闭相应基因表达的新基因阻断技术,在基因功能研究、基因治疗方面已显示出巨大的前景。目前,利用RNAi已抑制了包括cyclophilin、GAPDH、p53、c-myc在内的多个内源基因的表达。同时在艾滋病、病毒性肝炎等的治疗研究中也已取得一定进展。但对肝癌等恶性肿瘤中高表达的hTERT基因,国内外还未见相关研究报道。本研究利用RNAi技术,在体内外抑制hTERT基因表达,探讨RNAi对肝癌治疗的可行性。方法：设计干扰hTERT基因的小片段RNA,构建重组表达质粒pTzu6 1-shRNA-hTERT并导入肝癌SMMC7721细胞株和裸鼠移植瘤,在体内外诱导RNAi,采用流式细胞检测技术、RT—PCR法、免疫组化等同时检测RNAi治疗组和对照组hTERT基因表达及细胞增殖变化,结果：体外细胞实验显示,重组质粒pTZU6 1—shRNA—hTERT导入肝癌SMMC7721细胞株3～7天后,肝癌细胞生长抑制率达37．5％;细胞周期相分布发生显著变化,S期细胞明显减少,G1／G0期细胞显著增加;hTERT的mRNA表达由99．4％下调到53．1％,hTERT蛋白表达由86．3％下调到46．6％。裸鼠体内实验结果显示,质粒pTZu6 1-shRNA-hTERT注射裸鼠皮下移植瘤7天后,瘤体积明显缩小,hTERT的mRNA表达由99．1％下调到76．2％,hT．ERT蛋白表达由87．2％下调到61．8％。体内、外对照组各指标均无变化。结论：RNAi明显抑制了靶基因hTERT的表达及肝癌细胞增殖,是潜在的肿瘤治疗新方法。     

Suppression of Na<Superscript>+</Superscript>/H<Superscript>+</Superscript> exchanger 1 by RNA interference or amiloride inhibits human hepatoma cell line SMMC-7721 cell invasion

Na⁺/H⁺ exchanger 1 (NHE1), a primary regulator of intracellular pH (pHi) and extracellular pH (pHe), plays a significant role in acidifying the tumor microenvironment, possibly resulting in their malignant potential. However, currently, very little is known about the roles of NHE1 in invasion of hepatocellular carcinoma (HCC) cells. We have recently shown that NHE1 is over-expressed in HCC tissues and that this increased expression is associated with HCC invasiveness. In this study, we also found that NHE1 is over-expressed in HCC cell lines. Subsequently, we silenced NHE1 expression in the human HCC cell line SMMC-7721 using RNA interference (RNAi) and examined the invasiveness and proliferation of NHE1-silenced SMMC-7721 cells and the matrix metalloproteinase-2 (MMP-2) activity. The knockdown of NHE1 expression significantly inhibited the invasive ability of SMMC-7721 cells but had only a minor effect on the cellular proliferation rate. Moreover, NHE1 knockdown significantly reduced the secretion of MMP-2. Further experiment using amiloride (an inhibitor of NHE1) confirmed the above result. Together, these findings indicate that NHE1 has an important role in SMMC-7721 cell invasion and that NHE1 might be a new target of HCC treatment.     

TSA对人肝癌细胞SMMC-7721的抑制作用及其机制

目的:研究去乙酰化转移酶抑制剂TSA对肝癌细胞SMMC-7721的作用及其机理。方法:利用细胞计数,流式细胞仪分析细胞凋亡及细胞周期,Tunel试验研究TSA对肝癌细胞SMMC-7721的作用;利用western研究TSA对肝癌细胞蛋白表达的影响。结果:TSA可明显抑制肝癌细胞SMMC-7721的生长,并可诱导细胞凋亡。可阻滞肝癌细胞SMMC-7721细胞周期于G0/G1期。可增加p53,p21,bax等基因的表达,降低BCL-2的表达。结论:去乙酰化转移酶抑制剂TSA可明显抑制肝癌细胞SMMC-7721的生长并诱导其凋亡,其主要通过调控一些肿瘤相关基因的表达起作用。     

Adenovirus-mediated Il-24 expression suppresses hepatocellular carcinoma growth via induction of cell apoptosis and cycling arrest and reduction of angiogenesis

Previous studies have shown that interleukin (IL)-24 as a novel tumor suppressor gene has tumor-suppressor activity in a broad spectrum of human cancer cells both in vitro and in vivo. In this study, we explored the potential effect of adenovirus-mediated IL-24 gene therapy on human hepatocellular carcinoma (HCC) by using a HCC cell line, SMMC-7721. We constructed a recombinant adenovirus, AdVGFP/IL-24 expressing the marker green fluorescent protein (GFP) and the tumor-suppressor gene, IL-24. We demonstrated that AdVGFP/IL-24 treatment of SMMC-7721 cells in vitro significantly induced HCC cell cytotoxicity and apoptosis, and altered HCC cell cycling with an S-phase reduction and G2/M phase arrest, compared with AdVGFP, without IL-24 expresssion (p < 0.05). Furthermore, we also showed that the treatment of SMMC-7721 tumors by an intratumoral injection of AdVGFP/IL-24 significantly suppressed in vivo HCC growth in athymic nude mice, compared with AdVGFP treatment (p < 0.05). In addition, we also elucidated the molecular mechanism responsible for AdVGFP/IL-24-associated tumor suppression. These include: (1) upregulation of p53-independent apoptosis-associated caspase-3 and (2) downregulation of angiogenesis-associated vascular endothelial growth factor and CD34. Therefore, this study will provide a framework for future clinical applications of AdVGFP/IL-24 in HCC gene therapy.     

Role of the pituitary tumor transforming gene 1 in the progression of hepatocellular carcinoma

In order to demonstrate the role of the pituitary tumor transforming gene 1 (PTTG1) in the development of hepatocellular carcinoma (HCC) and its value as a molecular target for cancer therapy, we analyzed the expression of PTTG1 mRNA and protein, and their relation to clinicopathological characteristics and basic fibroblast growth factor (bFGF) expression in HCC. It was observed that the level of PTTG1 mRNA and the positive rate of PTTG1 protein in cancerous tissues were significantly higher than that in adjacent non-cancerous tissues (both P< 0.001). The PTTG1 protein levels were correlated with several clinicopathological parameters, including alpha-fetoprotein level, portal vein tumor thrombosis, tumor stage, and bFGF protein level (P< 0.05). The proliferation indices were significantly less and the apoptotic rates were significantly higher in the HepG2 and SMMC-7721 cells treated with PTTG1 siRNA transfection than their untransfected counterparts. The expressions of Caspase-3, Bax, p21 and p53 in HepG2 and SMMC-7721 cells were significantly increased after siRNA knockdown of PTTG1 expression. In conclusion, the PTTG1 gene is up-regulated in the cancerous tissue from patients with HCC and involved in the progression of HCC. Inhibiting PTTG1 expression decreases cell proliferation and induces apoptosis in hepatic cancer cell lines, indicating that PTTG1 may be a new therapeutic target for HCC treatment.     

重组腺病毒介导突变型p27基因转移对肝癌细胞SMMC-7721生长的影响

 目的 探讨突变型p27基因（p27mt）对肝癌细胞SMMC-7721的细胞增生和凋亡的调节作用。方法 利用重组体腺病毒Ad-p27mt转染培养的人肝癌细胞SMMC-7721，用3H -TdR掺入法检测细胞增生；流式细胞术、DNA片段分析法、TUNEL法检测细胞凋亡。结果 重组体腺病毒Ad-p27mt在MOI≥ 50时， 可达到100 %的转导效率。Ad-p27mt转染肝癌细胞后，3H -TdR掺入检测发现细胞增生抑制；流式细胞术检测在G1期前出现亚二倍体凋亡峰；细胞DNA抽提电泳后发现凋亡特征性梯带。Ad-p27mt组及空白对照组TUNEL法检测凋亡指数分别为58.6±4.3及4.5±1.6，差异有统计学意义（P＜0.01）。结论 重组腺病毒介导的p27mt基因转移可抑制肝癌SMMC-7721细胞增生并诱导其凋亡。     

Mig-6基因表达对肝癌细胞增殖和凋亡的影响

目的:研究Mig-6对肝癌细胞增殖和凋亡的影响,以探讨Mig-6在肝癌中的作用机制。方法:采用Mig-6过表达质粒和siRNA转染肝癌细胞,使用Real-time PCR和Western Blot法检测转染后的过表达或沉默效果;CCK-8实验检测细胞增殖水平的变化;流式细胞仪检测细胞凋亡百分比的变化;蛋白免疫印迹检测相关蛋白的表达变化。结果:转染Mig-6能抑制肝癌细胞的增殖,促进肝癌细胞的凋亡;干扰Mig-6能促进肝癌细胞的增殖,抑制肝癌细胞的凋亡。上调Mig-6能增加肝癌细胞Caspase-3 的活性,抑制P-ERK的磷酸化;干扰下调Mig-6能抑制肝癌细胞Caspase-3 的活性,增加P-ERK的磷酸化。结论:在肝癌细胞中,Mig-6表现出抑制细胞增殖及促进细胞凋亡的作用,该作用可能与Mig-6能增加Caspase-3 的活性,同时抑制P-ERK的表达有关。     

Andrographolide enhances 5-fluorouracil-induced apoptosis via caspase-8-dependent mitochondrial pathway involving p53 participation in hepatocellular carcinoma (SMMC-7721) cells

Despite recent significant advances in the treatment of human carcinoma (HCC), the results of chemotherapy to date remain unsatisfactory. 5-Fluorouracil (5-FU) still represents the cornerstone of treatment of carcinoma, and resistance to the actions of 5-FU is a major obstacle to successful chemotherapy. More effective treatment strategies may involve combinations of agents with activity against HCC. Andrographolide (ANDRO), a natural bicyclic diterpenoid lactone isolated from Andrographis paniculata, has been shown to suppress the growth of HCC cells and trigger apoptosis in vitro. To assess the suitability of ANDRO as a chemotherapeutic agent in HCC, its cytotoxic effects have been evaluated both as a single agent and in combination with 5-FU. ANDRO potentiates the cytotoxic effect of 5-FU in HCC cell line SMMC-7721 through apoptosis. ANDRO alone induces SMMC-7721 apoptosis with p53 expression, Bax conformation and caspase-3,8,9 activation. Surprisingly, the addition of ANDRO to 5-FU induces synergistic apoptosis, which could be corroborated to the increased caspase-8, p53 activity and the significant changes of Bax conformation in these cells, resulting in increased losses of mitochondrial membrane potential, increased release of cytochrome c, and activation of caspase-9 and caspase-3. Suppression of caspase-8 with the specific inhibitor z-IETD-fmk abrogates largely ANDRO/5-FU biological activity by preventing mitochondrial membrane potential disappearance, caspase-3,9 activation and subsequent apoptosis. The results suggest that ANDRO may be effective in combination with 5-FU for the treatment of HCC cells SMMC-7721.     

Smad4基因沉默促进PanIN裸鼠移植瘤增殖和微血管形成的研究

背景与目的:由已建立的小鼠基因打靶模型证实,K-ras突变启动了胰腺癌前病变一胰腺腺管内上皮瘤(pancreatic intraepithelial neoplasia,PanIN),p53或p16失活均可单独促进小鼠PanIN发展为浸润性胰腺癌.作为人胰腺癌中另一失活频率高发的抑癌基因Smad4,其失活对PanIN的转化作用及是否可单独促进PanIN发展为胰腺癌目前仍不清楚.基于此目的,在已成功分离建立K-ras突变启动的PanIN细胞株基础上,本研究拟进一步应用RNA干扰技术沉默PanIN细胞株中内源性Smad4表达,以探讨siRNA干扰Smad4基因对PanIN细胞恶性转化作用.方法:构建Smad4基因沉默慢病毒质粒,筛选Smad4沉默稳转细胞并命名为PanIN-S细胞;分别用PanIN和PanIN-S细胞并采用皮下接种的方法,构建获得PanIN及PanIN-S细胞组裸鼠移植瘤模型(每组5只),2周后测定各组肿瘤体积和质量;应用免疫组织化学SP法检测并比较各组增殖细胞核抗原(PCNA)和CD31的表达及其差异.结果:成功构建了Smad4基因SiRNA体系;与未干扰PanIN细胞组相比,PanIN-S组裸鼠肿瘤体积和质量显著增加(P<0.05);组织病理学检查,符合胰腺癌(腺癌);免疫组织化学结果显示PCNA和CD31表达显著增高(P<0.05).结论:Smad4基因沉默可促使在K-ras突变基础上的小鼠PanIN细胞的恶性转化;裸鼠移植瘤中Smad4失活可显著促进小鼠移植瘤增殖和肿瘤微血管形成,这些可能是其致瘤恶性转化的重要作用机制.     

Inhibition of Growth and Induction of Differentiation ofSMMC-7721 Human Hepatocellular Carcinoma Cells byOncostatin M

Oncostatin M (OSM) is a multifunctional cellular regulator acting on a wide variety of cells, which haspotential roles in the regulation of gene activation, cell survival, proliferation and differentiation. Previousstudies have shown that OSM can induce morphological and/or functional differentiation and maturation ofmany tumor cells. However, the action of OSM on the induction of differentiation of human hepatocellularcarcinoma (HCC) has not been reported. Here, we investigated the effects of different concentrations of OSMon human HCC cell line SMMC-7721 growth, proliferation, cell cycling, apoptosis and differentiation in vitro.Cell growth was determined via MTT assay, proliferation by cell cycle analysis, apoptosis by flow cytometry,morphology by transmission electronic microscopy, and cell function by detection of biochemical markers.Our results demonstrated that OSM strongly inhibited the growth of SMMC-7721 cells in a dose-dependentmanner, associated with decreased clonogenicity. Cell cycle analysis revealed a decreased proportion of cells inS phase, with arrest at G0/G1. The apotosis rate was increased after OSM treatment compared to the control.These changes were associated with striking changes in cellular morphology, toward a more mature hepaticphenotype, accompanied by significant reduction of the expression of AFP and specific activity of γ-GT, withremarkable increase in secretion of albumin and ALP activity. Taken together, our findings indicate that OSMcould induce the differentiation and reduce cell viability of SMMC-7721 cells, suggesting that differentiationtherapy with OSM offers the opportunity for therapeutic intervention in HCC.