重组人血管内皮抑制素对小鼠胃癌c-Myc,bFGF表达的影响

目的 通过构建荷胃癌小鼠模型研究重组人血管内皮抑制素对癌基因c-Myc和成纤维细胞生长因子(bFGF)表达的影响及可能机制.方法 20只小鼠皮下注射MFC小鼠前胃癌细胞从而构建小鼠胃癌移植瘤模型,后随机分成两组,每组10只,观察组腹腔注射0.8mg/kg重组人血管内皮抑素,对照组腹腔注射等量生理盐水.每天观察小鼠的一般情况,每3天测量肿瘤体积,绘制肿瘤体积生长曲线并对两实验组肿瘤体积进行比较;应用RT-PCR、Western bolt及免疫组织化学法检测两组小鼠肿瘤组织中c-Myc和bFGF的表达,免疫组织化学染色法检测肿瘤组织微血管密度(MVD)的表达,并通过Spearman分析c-Myc和bFGF两者的相关性.结果 在用药的过程中,对照组小鼠随着移植瘤结节的增大而发生行为明显改变,但观察组小鼠精神、反应、活动及进食饮水均如初,未见明显不良反应.治疗后第9d开始,观察组小鼠移植瘤体积明显小于对照组(P＜0.05),在第21 d最明显(P＜0.01).RT-PCR检测显示e-Myc,bFGF mRNA相对表达量明显低于对照组(P＜0.05);Western blot检测显也显示观察组c-Myc,bFGF蛋白的表达量明显低于对照组(P＜0.05);免疫组织化学检测显示c-Myc,bFGF阳性细胞数均明显低于对照组(P＜0.05),c-Myc,bFGF平均灰度值明显高于对照组(P＜0.05);对照组平均MVD为9.2±1.3,观察组为2.9±1.0,两组之间差异亦具有统计学差异(P＜0.05).且Spearman分析得出小鼠胃移植瘤中e-Myc和bFGF mRNA存在正相关(r=0.853,P=0.000).结论 重组人血管内皮抑制素通过抑制胃癌组织c-Myc,bFGF基因表达和血管生成.     

β-catenin及c-Myc蛋白表达与口腔鳞状细胞癌相关性研究

目的 探讨β-catenin和c-Myc在原发性口腔鳞癌(OSCC)中的表达及意义.方法 用免疫组化法检测口腔鳞癌及癌旁正常组织中3-catenin和c-Myc的表达.结果 β-catenin在口腔鳞癌、相应癌旁正常组织中异常表达率分别为56.92％、15.38％,两组之间差异具有统计学意义(P =0.006),β-catenin异常表达增多与肿瘤大小(P=0.003)、局部的淋巴结转移密切相关(P=0.017).在口腔鳞癌、相应癌旁正常组织中c-Myc的阳性表达率为64.62％,7.69％,两组之间差异具有统计学意义(P=0).β-catenin在胞质的表达与c-Myc的表达呈正相关(rs =0.237,P=0.049).结论 c-Myc在口腔鳞癌中过表达,作为原癌基因促进肿瘤发生;β-catenin胞浆异常表达可能与口腔鳞癌的侵袭转移有关.     

MicroRNA-130a associates with ribosomal protein L11 to suppress c-Myc expression in response to UV irradiation

The oncoprotein c-Myc is essential for cell growth and proliferation while its deregulated overexpression is associated with most human cancers. Thus tightly regulated levels and activity of c-Myc are critical for maintaining normal cell homeostasis. c-Myc is down-regulated in response to several types of stress, including UV-induced DNA damage. Yet, mechanism underlying UV-induced c-Myc reduction is not completely understood. Here we report that L11 promotes miR-130a targeting of c-myc mRNA to repress c-Myc expression in response to UV irradiation. miR-130a targets the 3′-untranslated region (UTR) of c-myc mRNA. Overexpression of miR-130a promotes the Ago2 binding to c-myc mRNA, significantly reduces the levels of both c-Myc protein and mRNA and inhibits cell proliferation. UV treatment markedly promotes the binding of L11 to miR-130a, c-myc mRNA as well as Ago2 in cells. Inhibiting miR-130a significantly suppresses UV-mediated c-Myc reduction. We further show that L11 is relocalized from the nucleolus to the cytoplasm where it associates with c-myc mRNA upon UV treatment. Together, these results reveal a novel mechanism underlying c-Myc down-regulation in response to UV-mediated DNA damage, wherein L11 promotes miR-130a-loaded miRISC to target c-myc mRNA.     

miR-145抑制c-Myc基因表达对鼻咽癌细胞增殖的影响

目的：探究miR-145影响鼻咽癌细胞增殖可能的机制。方法：采用Real-time PCR法检测鼻咽癌细胞株CNE-1、CNE-2、CNE-2Z和鼻咽部永生化上皮细胞株NP69中miR-145和c-Myc的mRNA表达水平,Western blotting法检测c-Myc的蛋白表达水平,双萤光素酶报告基因实验检测miR-145与基因c-Myc的关系。分别将miR-Negative control、miR-145 mimics和si-NC、si-c-Myc转染进入CNE-1细胞,采用Real-time PCR及Western blotting法检测转染效果,CCK-8法检测转染后细胞的增殖情况,以及碘化丙啶（IP）染色流式细胞术检测细胞周期情况。结果： miR-145在鼻咽癌细胞系中明显低表达。转染miR-145后明显抑制CNE-1细胞的增殖\[3 d: （1.03±0.02） vs （1.21 ± 0.02）, P<0.05\];\[ 4 d: （1.79±0.02） vs （2.09±0.07）, P<0.01\]和导致G1期阻滞\[（79.57±1.47）% vs （69.98±1.16）%,P<0.05\]。miR-145可以直接作用于c-Myc的3’UTR区域,抑制c-Myc的转录和表达。c-Myc下调可明显抑制CNE-1细胞的增殖\[3 d: （0.80±0.02） vs （1.02±0.01）, P<0.01\];\[4 d: （1.68±0.4） vs （1.92±0.07）, P<0.01\],并致G1期阻滞\[（63.73± 1.81）% vs （54.10±2.26）%,P<0.05\]。结论： miR-145通过靶向作用于c-Myc的3’UTR区来抑制鼻咽癌细胞的增殖,对更深入探索鼻咽癌的诊断和治疗有着重要意义。     

Role of TGF-β signaling in uterine carcinosarcoma

Uterine carcinosarcomas (UCS) are rare (3-4%) but highly aggressive, accounting for a disproportionately high (16.4%) mortality among uterine malignancies. Transforming growth factor beta (TGFβ) is a multifunctional cytokine that regulates important cellular processes including epithelial-mesenchymal transition (EMT). Existence of biphasic elements and a report demonstrating amplification of TGFβ at 19q13.1 prompted us to investigate the role of TGFβ signaling in UCS.Here we demonstrated the components of TGFβ pathway are expressed and functional in UCS. TGFβ-I induced significant Smad2/3 phosphorylation, migration and EMT responses in UCS cell lines which could be attenuated by the TGFβ receptor I (TGFβR-I) or TGFβ receptor I/II (TGFβR-I/II) inhibitor developed by Eli Lilly and company. Importantly, TGFβ-I induced proliferation was c-Myc dependent, likely through activation of cell cycle. c-Myc was induced by nuclear translocation of nuclear factor of activated T cells (NFAT-1) in response to TGFβ-I. Inhibition of NFAT-1 or TGFβR-I blocked c-Myc induction, cell cycle progression and proliferation in UCS. In corroboration, mRNA levels of c-Myc were elevated in recurrent versus the non-recurrent UCS patient samples. Interestingly, in the absence of exogenous TGFβ the TGFβR-I/II inhibitor enhanced proliferation likely through non-Smad pathways. Thus, inhibition of TGFβR-I could be efficacious in treatment of UCS.