Vaskivuo Liisa, Rysä Jaana, Koivuperä Johanna, Myllynen Päivi, Vaskivuo Tommi, Chvalova Katerina, Serpi Raisa, Savolainen Eeva-Riitta, Puistola Ulla, Vähäkangas Kirsi
Department of Pharmacology and Toxicology, University of Oulu, FI-90014 Oulu, Finland.
Toxicol Appl Pharmacol. 2006 Oct 1;216(1):89-97. doi: 10.1016/j.taap.2006.04.015. Epub 2006 May 19.
p14(ARF) tumor suppressor protein regulates p53 by interfering with mdm2-p53 interaction. p14(ARF) is activated in response to oncogenic stimuli but little is known of the responses of endogenous p14(ARF) to different types of cellular stress or DNA damage. Azidothymidine (AZT) is being tested in several clinical trials as an enhancer of anticancer chemotherapy. However, the knowledge of the relationship between AZT and cellular pathways, e.g. p53 pathway, is very limited. In this study, we show that AZT, cisplatin (CDDP) and docetaxel (DTX) all induce unique molecular responses in OVCAR-3 ovarian carcinoma cells carrying a mutated p53, while in A2780, ovarian carcinoma and MCF-7 breast carcinoma cells with wild type p53, all of these drugs cause similar p53 responses. We found that endogenous p14(ARF) protein in OVCAR-3 cells is down-regulated by DTX but induced by AZT and a short CDDP pulse treatment. In HT-29 colon carcinoma cells with a mutated p53, all treatments down-regulated p14(ARF) protein. Both CDDP and AZT increased the expression of p14ARF mRNA in OVCAR-3 cells. Differences in cell death induced by these drugs did not explain the differences in protein and mRNA expressions. No increase in the level of either c-Myc or H-ras oncoproteins was seen in OVCAR-3 cells after AZT or CDDP-treatment. These results suggest that p14(ARF) can respond to DNA damage without oncogene activation in cell lines without functional p53.
p14(ARF)肿瘤抑制蛋白通过干扰mdm2-p53相互作用来调节p53。p14(ARF)在致癌刺激下被激活，但对内源性p14(ARF)对不同类型细胞应激或DNA损伤的反应了解甚少。叠氮胸苷（AZT）正在多项临床试验中作为抗癌化疗的增强剂进行测试。然而，关于AZT与细胞通路（如p53通路）之间关系的了解非常有限。在本研究中，我们表明AZT、顺铂（CDDP）和多西他赛（DTX）在携带突变型p53的OVCAR-3卵巢癌细胞中均诱导独特的分子反应，而在具有野生型p53的A2780卵巢癌和MCF-7乳腺癌细胞中，所有这些药物都引起相似的p53反应。我们发现，DTX可下调OVCAR-3细胞中的内源性p14(ARF)蛋白，但AZT和短时间的CDDP脉冲处理可诱导该蛋白表达。在具有突变型p53的HT-29结肠癌细胞中，所有处理均下调p14(ARF)蛋白。CDDP和AZT均增加了OVCAR-3细胞中p14ARF mRNA的表达。这些药物诱导的细胞死亡差异并不能解释蛋白质和mRNA表达的差异。AZT或CDDP处理后，OVCAR-3细胞中c-Myc或H-ras癌蛋白水平均未升高。这些结果表明，在没有功能性p53的细胞系中，p14(ARF)可以在无癌基因激活的情况下对DNA损伤作出反应。
