Immunohistochemical demonstration of altered intracellular localization of the c-Myc oncogene product in human colorectal neoplasms

The distribution of the c-myc oncogene product p62 was examined by immunohistochemistry using the monoclonal antibody Mycl-9E10 in a series of 50 colorectal resections for carcinoma. The specimens were specially handled to ensure rapid fixation in formalin, and a significant improvement was shown in the quality and localization of staining compared with routinely handled specimens. Non-neoplastic mucosa showed the presence of nuclear staining of epithelial ceiis in 93 per cent of the samples, whilst all carcinomas showed cytoplasmic staining and infrequent nuclear staining. Adenomas showed an intermediate pattern, with significantly more frequent cytoplasmic distribution than non-neoplastic mucosa, but less than carcinomas. The results show that whilst fixation conditions are important in the immunolocalization of the C-myc protein product, there may be a consistent difference between non-neoplastic mucosa and carcinoma in the manner of association of p62 with the nucleus.     

小干扰RNA抑制c-Myc表达对MCF-7细胞增殖和凋亡的影响

目的应用小干扰RNA（siRNA）干扰乳腺癌MCF-7细胞的c-Myc表达，了解c-Myc对肿瘤细胞增殖和凋亡的作用。方法将c-Mye siRNA，经IApofectamineTM2000脂质体转染MCF-7细胞后，实时定量RT-PCR和Western Blotting法检测细胞cMyc mRNA和蛋白的表达，MTT法和流式细胞仪检测干扰后细胞的增殖和凋亡水平。结果转染后MCF-7细胞的c-Myc的mRNA与蛋白表达明显减弱，增殖能力显著降低。洲亡率明显提高。结论运用RNAi技术，可以有效地干扰MCF-7细胞c—Myc的表达，抑制细胞增殖，并诱导细胞渊亡。     

α-Hederin inhibits the growth of lung cancer A549 cells in vitro and in vivo by decreasing SIRT6 dependent glycolysis

Abstract

Context

α-Hederin, a potent bioactive compound of Pulsatilla chinensis (Bunge) Regel (Ranunculaceae), has many pharmacological uses, but its effect on cancer cell metabolism is still unclear.     

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.     

大肠表面型病变组织学和P53、c-Myc表达

目的研究人类大肠表面型病变的组织学特征及P53、c-Myc在大肠癌演变过程中的意义。方法采用免疫组化二步法,研究20例正常大肠黏膜、31例表面型病变、51例隆起型病变及31例大肠腺癌组织中P53、c-Myc的表达情况。结果大肠表面型病变的组织学均为腺瘤,且全部伴有不同程度的异型增生,与隆起型病变比较,两组中、重度异型增生的比例均有显著差异（P〈0.05）;大肠表面型病变的P53、c-Myc表达分别为3.2%及25.8%,其中P53表达与隆起型病变比较结果无差异（P〉0.05）,但c-Myc的表达两组有显著差异（P〈0.05）。结论大肠表面型病变与大肠癌关系密切,P53、c-Myc在其向大肠癌演变过程中起重要作用。     

B-catenin deficiency, but not Myc deletion, suppresses the immediate phenotypes of APC loss in the liver

Dysregulated Wnt signaling is seen in approximately 30% of hepatocellular carcinomas; thus, finding pathways downstream of the activation of Wnt signaling is key. Here, using cre-lox technology, we deleted the Apc gene in the adult mouse liver and observed a rapid increase in nuclear β-catenin and c-Myc, which is associated with an induction of proliferation that led to hepatomegaly within 4 days of gene deletion. To investigate the downstream pathways responsible for these phenotypes, we analyzed the impact of inactivating APC in the context of deficiency of the potentially key effectors β-catenin and c-Myc. β-catenin loss rescues both the proliferation and hepatomegaly phenotypes after APC loss. However, c-Myc deletion, which rescues the phenotypes of APC loss in the intestine, had no effect on the phenotypes of APC loss in the liver. The consequences of the deregulation of the Wnt pathway within the liver are therefore strikingly different from those observed within the intestine, with the vast majority of Wnt targets being β-catenin-dependent but c-Myc-independent in the liver.     

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.