代写论文 >> 医学论文 >> PPARγ胃癌表达曲格列酮对胃癌SGC7901生长影响
PPARγ胃癌表达曲格列酮对胃癌SGC7901生长影响
- 作者:admin 来源:网络 日期:2009-4-29 19:54:10
- 浓度TGZ对于SGC7901细胞发挥不同程度生长抑制作用，抑制作用具有浓度及时间依赖性，高浓度药物（50 μmol/L）与阴性对照组相比有显著性差异。至于其抑制肿瘤细胞生长的作用机制，结果提示TGZ可诱导SGC7901G0/G1的细胞比例增加、细胞凋亡增加。
研究显示PPARγ/RXR能被 PPARγ、RXR激动剂单独或协同激活形成PPARγ/RXR二聚体，再结合于PPRE激活目的基因转录而发挥调控作用［11］。其作用的机制主要有：①通过泛素-蛋白体蛋白降解途径，上调周期素依赖激酶抑制因子p21Waf1、p27Kip1的表达［12-13］；②通过抑制炎症及核转录相关因子（如TNF、IL-4、NF-κB）的活性而抑制肿瘤细胞的生长［14-15］；③降低凋亡抑制蛋白Bcl-2和Bcl-XL的表达，从而激活caspase-3介导的细胞凋亡途径［16］；④抑制肿瘤血管内皮细胞增殖，从而抑制肿瘤血管生成［17］。那么如何去理解PPARγ在胃癌中高表达，而其激动剂却可以抑制胃癌细胞生长的作用，根据实验结果可以推测在胃癌中可能存在PPARγ过表达与RXR表达失平衡而无法形成有效的PPARγ/RXR二聚体进而发挥其抗肿瘤作用。因此进一步探讨RXR在胃癌中的表达及其联合使用二者激动剂对胃癌细胞的影响将是本研究继续研究的方向与内容。
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