两种不同类型ING1表达对人癌细胞生长影响的比较

Effects of two variants of ING1 expression on tumor cell growth regulation

目的 比较两种不同类型ING1剪接体表达对人癌细胞系生长影响的异同及其作用。方法 构建人p3 3 /ING1A和p47/ING1B表达重组子 ,用瞬时转染和稳定转染法分别导入表达野生型p5 3的人乳腺癌细胞系MCF 7和肺癌细胞系PAa ,用噻唑蓝比色法和软琼脂集落形成观察其生长变化及用Westernblot法检测相关基因表达状况。结果 瞬时和稳定转染后两种癌细胞系都有p47/ING1A和p3 3 /ING1B表达 ,但p3 3 /ING1表达量明显高于p47/ING1。外源性p3 3 /ING1B高表达对细胞生长具有抑制作用 ,细胞出现G0 ～G1期阻滞 (P <0 .0 1) ;外源性p47/ING1A过表达对细胞生长无明显影响。转染p3 3 /ING1B并出现生长抑制的肿瘤细胞p2 1WAF1表达水平明显升高 ,但p5 3表达并没有变化。结论 两种不同类型ING1剪接体过量表达对肿瘤细胞生长具有不同影响。外源性p3 3 /ING1B过量表达可以促进p2 1WAF1表达 ,协同p5 3引起细胞周期阻滞从而抑制肿瘤细胞生长 ,是p5

Objective To study effects of alternative transcripts of ING1 transfection on human cancer cell lines. Methods p47/ING1A and p33/ING1B expression vehicles were constructed and introduced into a human breast cancer cell line MCF-7 and a human lung cancer cell line PAa, both expressing wild-type p53 protein. Growth characteristics of the transfectants and potentially related genes were analyzed. Results The levels of p47/ING1A and p33/ING1B protein elevated respectively in tumor cells of MCF-7 and PAa after transfected with p47/ING1A and p33/ING1B, and the latter was much higher than that of the former. Ectopic overexpression of p33/ING1B effectively blocked tumor cell growth and arrested cells in the G 0～G 1 phase of the cell cycle (P<0.01), while p47/ING1A gave no effect on cell growth or cell cycle. Tumor cells overexpressing p33/ING1B contained more p21 WAF1 protein than that of the control cells, with undisturbed p53 protein level. Conclusions Expression of two different transcripts of ING1 may have different effects on tumor cell growth. p33/ING1B may cooperate with p53 in stimulating expression of p21 WAF1 gene, thus to arrest cell cycle and to inhibit tumor cell growth. p33/ING1B may be considered to be a candidate as a partner of p53 in gene therapy.