K-ras基因点突变的反义寡脱氧核苷酸对体外培养的人胰腺癌细胞PC-2凋亡的影响

目的观察针对于胰腺癌K-ras基因点突变的反义寡脱氧核苷酸对体外培养人胰腺癌细胞株PC-2凋亡的影响。方法脂质体将人工合成的针对于K-ras基因第12位密码子点突变的反义寡脱氧核苷酸转染体外培养的人胰腺癌细胞株PC-2,流式细胞仪、凋亡细胞原位末端标记（TUNEL）、倒置相差显微镜检测反义寡脱氧核苷酸对人胰腺癌细胞PC-2凋亡的影响。结果转染48小时后,流式细胞仪：实验组有明显的凋亡峰,细胞大部分被阻滞于G1期,S期比例减少。TUNEL：实验组凋亡细胞明显增多。倒置相差显微镜：实验组凋亡小体明显增多。结论针对于K-ras基因点突变的反义寡脱氧核苷酸作用于体外培养的胰腺癌细胞PC-2,对癌细胞的凋亡有明显的促进作用。     

Small interfering RNAs targeting mutant K-ras inhibit human pancreatic carcinoma cells growth in vitro and in vivo

AIM: To investigate the effect of small interfering RNAs targeting mutant K-ras on the growth of pancreatic carcinoma cell lines in vitro and in vivo. MATERIALS AND METHODS: We cloned targeting sequence spanning codon 12 of mutant K-ras into the pSilencer-hygro plasmid, yielding two recombinant vectors with one base different. Both human pancreatic carcinoma cell lines were transfected by these two recombinant vectors. The transfected PC-7 cells were injected subcutaneously into nude mice to observe its tumorigenicity. RT-PCR and Western blot analysis were carried out to test the expression of K-ras in all of the transfected cell lines. Growth curves assay were performed to test the abilities of cells proliferation. Anti-K-ras therapy of PC-7 and Panc-1 in subcutaneous mice models were performed by intratumor injection of polyethylenimine/siRNAs complex. RESULTS: The expressions of K-ras in PC-7 cells and Panc-1 cells were significantly inhibited by corresponding small interfering RNAs. The expression of K-ras was particularly inactivated by siRNA without any base mismatch to its homologous mRNA, while this oncogene with central base mismatch could not be inhibited as effectively as that of the former. The growth of PC-7 cells and Panc-1 cells transfected by corresponding mutant K-ras targeted siRNAs were significantly suppressed when compared with controls (p<0.05). The transfected PC-7 cells lost tumorigenic ability. Four weeks treatment of Xenograft of pancreatic carcinoma (PC-7 and Panc-1) in nude mice with Polyethylenimine-encapsulated mutant K-ras targeted siRNAs (20 microg/mouse twice weekly) were effective in reducing tumor growth, when compared with controls (p<0.05). CONCLUSION: The central base may play a key role in the process of RNA interference. The mutant point and its vicinity of 19 nucleotides in K-ras may be the effective targeting sequence for RNA interference. Targeting mutant-k-ras therapy of pancreatic carcinoma may be a clinically applicable therapeutic modality.     

Intraperitoneal injection of adenovirus expressing antisense K-ras RNA suppresses peritoneal dissemination of hamster syngeneic pancreatic cancer without systemic toxicity

We examined the antitumor effect and safety of the adenovirus-mediated expression of antisense K-ras RNA in two peritoneal dissemination models of pancreatic cancer. First, we found that the infection of an adenovirus vector expressing antisense human K-ras RNA (AxCA-AS) induced significant apoptosis in vitro in human pancreatic cancer cells with K-ras mutation. Second, the intraperitoneal (ip) injection of AxCA-AS effectively suppressed the growth of human pancreatic cancer cells in the peritoneal cavity of nude mice. Third, in the hamster syngeneic peritoneal dissemination model, the ip injection of an adenovirus expressing antisense hamster K-ras RNA significantly suppressed the peritoneal growth of hamster pancreatic cancer cells, and no significant systemic toxicity was observed in the treated hamsters. This study suggests a feasibility of the development of a therapeutic strategy against pancreatic cancer based on the adenovirus-mediated transduction of an antisense K-ras construct.     

Enhanced radiation sensitivity in prostate cancer by inhibition of the cell survival protein clusterin.

PURPOSE: The purpose of this study is to evaluate the role of the cell survival gene clusterin in radiation-induced cell death in human LNCaP and PC-3 prostate cancer models. Experimental Design: Radiation sensitivities were compared in parental and clusterin-overexpressing LNCaP cells and in PC-3 cells and tumors treated with antisense or mismatch clusterin oligonucleotides. RESULTS: Clusterin-overexpressing LNCaP cells were less sensitive to irradiation with significantly lower cell death rates (23% after 8 Gy) compared with parental LNCaP cells (50% after 8 Gy) 3 days after irradiation. Clusterin expression in PC-3 cells after radiation was found to be up-regulated in a dose-dependent manner in vitro by 70% up to 12 Gy and in vivo by 84% up to 30 Gy. Inhibition of clusterin expression in PC-3 cells using antisense oligonucleotides (ASOs) occurred in a sequence- and dose-dependent manner and significantly enhanced radiation-induced apoptosis and decreased PC-3 cell growth rate and plating efficiency. Compared with mismatch control oligonucleotide treatment, clusterin ASO treatment enhanced radiation therapy and significantly reduced PC-3 tumor volume in vivo by 50% at 9 weeks. In addition, TUNEL staining revealed increased number of apoptotic cells in clusterin ASO-treated and irradiated PC-3 tumors, compared with treatment with mismatch control oligonucleotides plus radiation. CONCLUSIONS: These findings support the hypothesis that clusterin acts as a cell survival protein that mediates radioresistance through the inhibition of apoptosis. In vivo results further suggest that inactivation of clusterin using ASO technology might offer a novel strategy to improve results of radiation therapy for prostate cancer patients.     

K-ras和IGF-IR反义寡核苷酸联合转染对人胰腺癌Patu8988细胞增殖和凋亡的影响

背景与目的:已有研究表明K-ras基因点突变及胰岛素样生长因子Ⅰ受体(insulin-like growth factor receptor type1,IGF-IR)过表达在胰腺癌的发生发展过程中起着重要作用,针对K-ras mRNA和IGF-IR mRNA的反义寡核苷酸(antisense oligodeoxynucleotide,ASODN)均可抑制胰腺癌细胞的增殖。本研究旨在探讨针对K-ras基因12密码子点突变的硫代反义寡核苷酸(K-ras ASODN)联合IGF-IR硫代反义寡核苷酸(IGF-IR ASODN)对人胰腺癌Patu8988细胞体内外增殖和凋亡的影响。方法:顺序特异引物聚合酶链反应(polymerase chain reaction using special sequence primers,PCR-SSP)法和基因测序检测Patu8988细胞K-ras点突变形式,根据点突变形式设计并合成K-ras ASODN。K-ras ASODN和IGF-IR ASODN分别单独和联合作用Patu8988细胞后,通过四甲基偶氮唑蓝(MTT)法、克隆形成实验及透射电镜观察其对Patu8988细胞增殖及形态结构的影响;流式细胞术(FCM)检测K-ras和IGF-IR蛋白表达和细胞凋亡;RT-PCR检测K-ras和IGF-IR mRNA表达水平;以Patu8988细胞建立裸鼠人胰腺癌模型,观察K-ras ASODN与IGF-IR ASODN联合应用在体内的抗肿瘤效果。结果:PCR-SSP法和基因测序检测表明Patu8988细胞存在K-ras基因第12密码子点突变,其突变方式为GGT→GTT。2～32mg/L的K-ras ASODN和2～32mg/L的IGF-IR ASODN单独应用均能一定程度抑制Patu8988细胞增殖、诱导细胞凋亡,两者联合应用较单独应用抑制作用更为显著(P<0.01)。体内实验表明,K-ras ASODN与IGF-IR ASODN联合应用较单独应用能更有效地抑制BALB/c裸鼠胰腺癌的生长(P<0.01)。结论:K-ras ASODN和IGF-IF ASODN两种反义寡核苷酸对人胰腺癌Patu8988细胞增殖的抑制具有协同作用,其机制可能是联合下调K-ras、IGF-IR蛋白及K-ras、IGF-IR mRNA表达水平。     

多层螺旋CT同层动态扫描结合MPR技术诊断肝外胆管癌的研究

Objective:To investigate the cell cycle changes of hepatoma cells and the rote of antisense oligonucleotide targeting bFGF.Methods:Inhibition of bFGF protein expression was investigated by conical microscopy analysis and Western blot in the best condition of transfecting antisense oligonucleotide targeting bFGF.Cell cycle and apoptosis were detected with flow cytometry analysis.Results:Treatmenl with antisense oligonucleotide of bFGF not only reduced the expression of bFGF by conical microscopy and Western blot analysises,but also increased the apoptosis of HepG2 cells(P＜0.01).Conclusion:bFGF may take part in apoptosis regulation of hepatoma cells and be used as a target of hepatocel-lular carcinoma therapy.     

c-Ki-ras point mutations in ductectatic-type mucinous cystic neoplasms of the pancreas

Ductectatic-type mucinous cystic neoplasms of the pancreas constitute a recently recognized new human pancreatic tumor entity. Examination for the presence of point mutations at codon 12 of K-ras by oligonucleotide hybridization in 5 adenomas and 3 carcinomas revealed alteration in 3 and 2, respectively. In 4 of these positive cases, the transition was GGT----GAT (Gly----Asp) with the remaining one, found in a cancer, being GGT----GTT (Gly----Val). In two carcinoma cases, the same point mutation was detected both in the carcinoma area and in a coexisting adenoma component. Thus K-ras point mutation appears to be associated with this particular type of neoplasm in the same manner as observed for typical exocrine pancreas carcinomas. Our study also indicates the possible existence of an adenoma-carcinoma sequence in the evolution of this type of neoplasm and we suggest that K-ras activation may be an important event in the phase of adenoma development.     

抗clusterin 反义核酸治疗提高肺癌H460细胞放射敏感性的实验研究

目的：研究抑制clusterin的表达对肺癌H460细胞放射敏感性的影响。方法：用脂质体转染的方法将抗clusterin反义核酸转染肺癌H460细胞，以^137Cs作为放射源对肺癌细胞进行放射干预。用流式细胞仪检测抗clusterin反义核酸治疗和放射干预对肺癌细胞凋亡的影响，用MTT法和克隆形成分析方法检测抗clusterin反义核酸治疗和放射干预对肺癌细胞增殖的影响。结果：抗clusterin反义核酸特异性抑制了分泌型clusterin的表达，而对核型clusterin的表达无明显作用。单纯放射干预或单纯反义核酸转染将凋亡细胞数提高了10％，反义核酸治疗联合放射干预使肺癌H460细胞的凋亡细胞数增加了25％，和单纯放疗或单纯反义核酸转染组比较有显著性差异（P〈0．01）。MTT和体外克隆计数分析显示抗clusterin反义核酸治疗联合放疗干预显著抑制了肺癌H460细胞的增殖（P〈0．01）。结论：体外实验提示抗clusterin反义核酸治疗可以提高肺癌细胞对放射的敏感性。     

Synergistic inhibition of tumor growth and metastasis by combined treatment with TNP-470 and docetaxel in a human prostate cancer PC-3 model

TNP-470, a potent inhibitor of angiogenesis, was reported to synergistically enhance the antitumor effects of cytotoxic agents. The objective of this study was to evaluate the effectiveness of combined treatment with TNP-470 and docetaxel both in vitro and in vivo using androgen-independent human prostate cancer PC-3 cells. The in vitro growth-inhibitory and apoptotic effects of docetaxel and/or TNP-470 on PC-3 cells were assessed using MTT and TUNEL assays. The combined effect of docetaxel and TNP-470 therapy after subcutaneous and orthotopic injection of PC-3 cells into athymic nude mice was evaluated. In vivo effects of this combined regimen on PC-3 tumors were analyzed by the TUNEL assay and immunohistochemical staining of CD31 to quantify microvessel density (MVD). Combined treatment with TNP-470 and docetaxel synergistically inhibited PC-3 cell growth in vitro through the enhanced induction of apoptotic cell death compared with treatment with either agent alone, a result explained, at least in part, by the down-regulation as well as phosphorylation of potential anti-apoptotic genes, Bcl-2 and Bcl-XL. Combined treatment with TNP-470 and docetaxel synergistically suppressed subcutaneous PC-3 tumor growth compared with treatment with either agent alone. Furthermore, this combined regimen significantly inhibited orthotopic PC-3 tumor growth and reduced the incidence of lymph node metastasis. Immunohistochemical analysis of the subcutaneous tumor after each treatment demonstrated that administration of docetaxel as well as TNP-470 significantly induced apoptotic cell death; in contrast, a significant reduction in MVD was observed only after TNP-470. These findings suggest that docetaxel and TNP-470 act synergistically to inhibit PC-3 tumor growth and metastasis, by enhancing apoptosis and suppressing angiogenesis.     

端粒酶反义寡核苷酸诱导肝癌细胞凋亡的实验

目的研究端粒酶反义寡核苷酸对肝癌细胞株的凋亡诱导作用及其机制。方法以人肝癌细胞株SMMC-7721、正常肝细胞株L-02为研究对象,采用TRAP-ELISA法对肿瘤细胞端粒酶活性进行定性定量分析;细胞形态学、TUNEL染色、DNA 琼脂糖凝胶电泳观察端粒酶反义寡核苷酸对肝癌细胞的凋亡诱导作用,用流式细胞仪对细胞周期进行时相分析,Western杂交对细胞周期蛋白进行研究。结果一定浓度的端粒酶反义寡核苷酸可抑制肝癌细胞端粒酶活性,肝癌细胞端粒酶活性被抑制后传代23～26次出现细胞凋亡。细胞凋亡与细胞周期蛋白有关。结论端粒酶反义寡核苷酸可抑制肝癌细胞端粒酶活性并诱导其凋亡。     

碱性成纤维细胞生长因子反义寡核苷酸对肝癌细胞凋亡的影响

目的 检测碱性成纤维细胞生长因子(bFGF)反义寡核苷酸对肝癌细胞凋亡的影响,探讨bFGF作为肝癌治疗靶点的有效性.方法 以脂质体作为转染载体,转染bFGF反义寡核苷酸于HepG2细胞,用共聚焦显微镜和Western blot方法,检测转染bFGF反义寡核苷酸后肝癌细胞株HepG2中bFGF蛋白的表达,用流式细胞仪检测转染bFGF反义寡核苷酸后HepG2细胞的凋亡率.结果 与转染错义寡核苷酸组相比,bFGF反义寡核苷酸对HepG2细胞中bFGF蛋白表达有明显抑制作用,转染bFGF反义寡核苷酸可明显增加HepG2细胞的凋亡率(P＜0.01).结论 bFGF在肝癌细胞凋亡中有重要调节作用,可作为肝癌增敏治疗的有效靶点.     

PCR-SSP法检测人胰腺癌细胞株PCNA-1的K-ras基因点突变的方式

目的检测人胰腺癌细胞株PANC-1的K-ras基因点突变方式,明确干扰Ras基因靶点的碱基序列。方法针对K-ras基因第十二位点密码子点突变最常见方式CAT,CGT,GTT设计顺序特异性引物(SSP),对人胰腺癌细胞株PANC1进行聚合酶链反应(PCR),扩增产物用聚丙烯酰胺凝胶电泳判定该细胞株有无点突变及突变方式。结果人胰腺癌细胞株PANC-1存在K-ras基因的点突变,其突变方式为CAT。结论 PCR-SSP法快速简便,特异性高,结果准确,为应用RNAi技术研究胰腺癌的基因治疗奠定了基础。     

Comparison of K-ras point mutations at codon 12 and p21 expression in pancreatic cancer between Japanese and Chinese patients

BACKGROUND ANF OBJECTIVES: K-ras (Kirsten-ras) point mutation (PM) in codon 12 are suggested to be significantly associated with the tumorigenesis of pancreatic cancer. The incidences of K-ras PMs in human pancreatic cancer are reported to be different between Europeans and Japanese. The present study was designed to compare the incidences and profile of K-ras PMs and ras-p21 expression in primary invasive ductal carcinoma (IDC) of the pancreas between Japanese and Chinese. METHODS: The specimens included 51 Japanese and 34 Chinese patients with the primary IDC of the pancreas. K-ras PMs were tested by allele specific oligonucleotide dot blot hybridization methods and ras-p21 expression was stained by the immunohistochemical method. RESULTS: K-ras PMs were detected in 48 Japanese IDCs (94%) and in 24 Chinese ones (71%). There was a significant difference between the two groups. The GAT mutation was more frequent both in Japanese (61%, 33/54) and in Chinese (60%, 18/30) IDCs. The transitions/transversions ratio in the Japanese group was 2.4 in this study. By contrast, that in the Chinese group was 1.5. The expression of p21 was detected in 24 Japanese IDCs (47%) and in 24 Chinese IDCs (71%). There was a significant difference between the two groups. The expression of p21 and the patterns of K-ras PMs did not show any significant influence on the survival of the patients both in Japanese and Chinese. In the present study, Chinese IDC had a lower frequency of K-ras PMs in codon 12 than Japanese IDC. The pattern of K-ras PMs in Chinese IDC was different from that in Japanese and European IDC, respectively. CONCLUSIONS: Ki-ras PM and p21 expression were frequently seen both in Japanese and Chinese patients with pancreatic cancer. Factors such as lifestyle and environment may have influences on pancreatic carcinogenesis in various populations.     

Overexpression of BCL-X(L) underlies the molecular basis for resistance to staurosporine-induced apoptosis in PC-3 cells

We have reported previously that among human prostate cancer cell lines LNCaP but not PC-3 cells undergo apoptosis after treatment with the protein kinase inhibitor staurosporine (STS). We have now further investigated this model to uncover the molecular mechanism causing resistance to STS-induced apoptosis in PC-3 cells. S-100 lysates of both cell lines showed biochemical changes typical of apoptosis after the addition of cytochrome c and dATP, suggesting that the postmitochondrial phase of apoptosis was intact. Upon addition of STS, the proapoptotic molecules Bax and Bad became predominantly mitochondrial in both cell lines. This, in turn, was followed by loss of mitochondrial transmembrane potential, translocation of cytochrome c to the cytosol, activation of caspase-9, -3, and -7, and cleavage of the apoptotic targets, DNA fragmentation factor and poly(ADP-ribose) polymerase, in LNCaP but not in PC-3 cells. Components of the mitochondrial permeability transition pore, adenine nucleotide transporter and voltage-dependent anion channel, were normally expressed in the correct subcellular fraction of both cell lines. Overexpression of the proapoptotic proteins Bax and Bad, fused to a green fluorescent protein but not of green fluorescent protein alone, induced apoptosis in >80% of PC-3 cells. These experiments suggested that a factor protecting the mitochondria of PC-3 cells mediates resistance to STS-induced apoptosis. A wide search among the antiapoptotic Bcl-2 family members was performed, and Bcl-X(L) was found to be overexpressed in PC-3 cells. Experiments down-regulating Bcl-X(L) expression by using the tyrosine kinase inhibitor genistein, sodium butyrate, or an antisense Bcl-X(L) oligonucleotide restored sensitivity to apoptosis in PC-3 cells. Thus, Bcl-X(L) overexpression is one of the mediators of resistance to STS-induced apoptosis in the prostate cancer cell line PC-3.     

基因放射性核素反义治疗肾癌的体内外实验

目的:探讨Ki-67基因放射性核素反义治疗对人肾癌细胞生长及凋亡的影响。方法:125I标记的反义核酸(125I-ASODNs)处理人肾癌786-0细胞及荷瘤小鼠,采用免疫组化、Westernblot检测Ki-67表达;TUNEL法检测细胞凋亡。结果:肾癌细胞Ki-67抗原表达降低、Ki-67蛋白降低、凋亡细胞阳性率升高、小鼠肿瘤体积减小。结论:Ki-67基因放射性核素反义治疗能抑制肾癌细胞Ki-67基因表达及细胞增殖、促进凋亡。     

Activated K-ras is involved in regulation of integrin expression in human colon carcinoma cells

Integrins participate in controlling proliferation and migration. Therefore, changes in integrin expression might be responsible for unrestrained proliferation and invasiveness of tumor cells. Alterations of integrin subunit expression have been observed in human colon carcinoma, especially loss or reduction of the alpha5 subunit, which was observed consistently. The mechanisms responsible for reduction of alpha5 expression and alteration of expression of other integrins are not fully understood. Circumstantial evidence from previous investigations points to an involvement of activated ras oncogenes in repression of integrin expression. The K-ras protooncogene is activated by point mutation in 50% of human colon carcinomas. Thus, we choose an antisense approach for specific inactivation of activated K-ras in the human colon carcinoma cell line SW 480 in order to test whether activated K-ras contributes to changes in integrin expression on colon carcinoma cells. Cell surface expression of the alpha1 and the alpha5 subunit was increased in K-ras antisense transfected clones, cell surface expression of the alpha3 subunit and the alphav subunit was decreased. This shows, in a human system, that activated K-ras is involved in diminishing cell surface expression of the alpha1beta1 collagen/laminin receptor and the alpha5beta1 fibronectin receptor, both of which are implicated in maintenance of a non-transformed phenotype. Moreover, activated K-ras contributes to increased cell surface expression of the alpha3beta1 laminin/collagen/fibronectin receptor and the alphavbeta5 vitronectin receptor, which might play a role in metastatic behavior of tumor cells.