【文章內(nèi)容簡(jiǎn)介】 cadherin基因本身并未發(fā)生缺失突變（12）。Yu（2002）進(jìn)一步研究顯示Tcadherin基因啟動(dòng)子在肝癌中高度甲基化，而Ecadherin基因啟動(dòng)子在肝癌中不發(fā)生甲基化，表明在Cadherin細(xì)胞粘附分子超家族中Tcadherin基因啟動(dòng)子甲基化在肝癌中具有高度特異性,且Tcadherin基因啟動(dòng)子甲基化與Tcadherin基因失活密切相關(guān)（26）這些。研究表明Tcadherin基因啟動(dòng)子甲基化是Tcadherin基因在肝癌中失活的主要機(jī)制。Takeuchi在對(duì)皮膚鱗癌細(xì)胞株的研究中發(fā)現(xiàn)，與2ug/ml去甲基化藥物5aza2’deoxycytidine共孵6天能使皮膚鱗癌細(xì)胞株恢復(fù)Tcadherin分子表達(dá)（17）。但目前對(duì)Tcadherin基因失活與肝癌惡性分化程度、肝內(nèi)轉(zhuǎn)移及復(fù)發(fā)等惡性生物學(xué)特征的關(guān)系，以及應(yīng)用去甲基化藥物是否能誘導(dǎo)Tcadherin分子在肝癌細(xì)胞株中重新表達(dá)，并抑制肝癌細(xì)胞的增殖、侵襲及轉(zhuǎn)移等惡性特征全世界尚無(wú)研究報(bào)道。本研究將進(jìn)一步研究Tcadherin在肝癌中的基因功能，調(diào)查缺失表達(dá)Tcadherin的肝癌細(xì)胞株重新表達(dá)Tcadherin是否能抑制肝癌細(xì)胞的增殖、侵襲及轉(zhuǎn)移等惡性生物學(xué)特征，并在裸鼠肝癌模型上加以證實(shí)。同時(shí)，進(jìn)一步研究其基因功能的分子機(jī)制。在臨床切除的肝癌標(biāo)本中研究Tcadherin基因失活與肝癌惡性分化程度、轉(zhuǎn)移及復(fù)發(fā)等惡性生物學(xué)特征的關(guān)系，進(jìn)一步揭示Tcadherin基因失活與臨床肝癌預(yù)后的關(guān)系。在肝癌細(xì)胞株及裸鼠肝癌模型上證實(shí)是否去甲基化藥物能重新誘導(dǎo)Tcadherin分子表達(dá)，并抑制肝癌細(xì)胞的增殖、侵襲及轉(zhuǎn)移等惡性生物學(xué)特征，觀察其潛在的治療作用和可能的毒副作用。由于國(guó)內(nèi)外尚無(wú)類似研究報(bào)道，申請(qǐng)人具有研究Tcadherin基因與C6細(xì)胞惡性生物學(xué)特征的關(guān)系及其分子機(jī)制的豐富經(jīng)驗(yàn)，預(yù)期該研究成果能達(dá)國(guó)際先進(jìn)水平。主要參考文獻(xiàn)： 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parative genomic Chromosomes ,18: J, Ni M, Xu J, et profiling of twenty promoterCpG islands of genes which may contribute to hepatocellular Cancer 2002, 2:29項(xiàng)目的研究?jī)?nèi)容、研究目標(biāo)，以及擬解決的關(guān)鍵問(wèn)題一、研究Tcadherin在肝癌中的基因功能 ，使其表達(dá)Tcadherin分子，研究表達(dá)Tcadherin分子的肝癌細(xì)胞的增殖、侵襲及轉(zhuǎn)移等惡性生物學(xué)特征的變化，證實(shí)是否Tcadherin重新表達(dá)能抑制肝癌細(xì)胞的增殖、侵襲及轉(zhuǎn)移等惡性生物學(xué)特征。 的HepG2細(xì)胞于皮下接種裸鼠，在裸鼠肝癌模型上進(jìn)一步證實(shí)Tcadherin基因的腫瘤抑制基因功能。3．研究Tcadherin基因在肝癌中腫瘤抑制功能的分子機(jī)制。證實(shí)是否Tcadherin在肝癌細(xì)胞株存在與在C6細(xì)胞中一致的分子機(jī)制，即Tcadherin分子通過(guò)誘導(dǎo)P21 CIP1/WAF1表達(dá)致使肝癌細(xì)胞于細(xì)胞周期G2期阻滯。二、在臨床切除的肝癌標(biāo)本中研究Tcadherin基因失活與肝癌惡性分化程度、轉(zhuǎn)移及復(fù)發(fā)等惡性生物學(xué)特征的關(guān)系，在人肝癌中揭示Tcadherin基因失活與肝癌的惡性生物學(xué)特征及預(yù)后的關(guān)系。，揭示Tcadherin基因表達(dá)水平（失活）與肝癌惡性分化程度、肝內(nèi)轉(zhuǎn)移（包括合并門(mén)靜脈癌栓和衛(wèi)星灶形成）的關(guān)系。，選擇在臨床分期、病理類型及治療方法上具有可比性的肝癌病例，分別選取肝癌切除術(shù)后半年內(nèi)復(fù)發(fā)或肝外轉(zhuǎn)移以及2年 內(nèi)未復(fù)發(fā)或肝外轉(zhuǎn)移的肝癌病例的石蠟標(biāo)本各20例，研究Tcadheri