姜黄素诱导人成骨肉瘤MG-63细胞凋亡过程中hnRNP A2/B1表达与定位

姜黄素(curcumin)诱导处理的人成骨肉瘤MG-63细胞,在光镜和电镜观察细胞凋亡的基础上,对hnRNP A2/B1在核基质中存在、分布及其与凋亡相关基因产物在MG-63细胞中的共定位关系进行了研究.经姜黄素处理后,细胞出现染色质凝聚、细胞核固缩、凋亡小体等典型的细胞凋亡形态特征;双向凝胶电泳和质谱鉴定结果显示,hnRNP A2/B1存在于MG-63细胞核基质蛋白组分中,在姜黄素处理后细胞核基质蛋白中表达下调.蛋白质印迹杂交结果,证实hnRNP A2/B1在姜黄素处理前后的MG-63细胞核基质蛋白中的存在及其表达下调变化.免疫荧光显微镜观察显示,hnRNP A2/B1定位于MG-63细胞核基质纤维上,经姜黄素处理后出现分布位置与表达水平变化.激光扫描共聚焦显微镜的观察结果显示,hnRNP A2/B1在MG-63细胞凋亡过程中与Bax、Bcl-2、Fas和p53等基因产物具有共定位关系,且其共定位区域发生了变化.研究结果证实了hnRNP A2/B1定位于核基质纤维上,是一种核基质蛋白,在姜黄素诱导人成骨肉瘤MG-63凋亡过程中的表达与分布变化及其与凋亡相关基因的关系显然对MG-63细胞凋亡具有重要影响,这为深入揭示肿瘤细胞凋亡的机制提供了重要科学依据和深入探索的新方向.

Curcumin induced Apoptosis Affects the Expression and Localization of hnRNP A2/B1 in Human Osteosarcoma MG 63 Cell

The morphology of human osteosarcoma MG-63 cells under light microscopy and transmission election microscopy was altered when treated with curcumin. The distribution of heterogeneous nuclear ribonucleoprotein (hnRNP)A2/B1 in the nuclear matrix and its colocalization with the apoptosis-related gene products were examined. The results demonstrated that curcumin induced typical apoptotic responses, such as chromatin agglutination, nuclei condensation, and apoptotic body formation. Two-dimentional PAGE and mass spectrum analyses showed that hnRNP A2/B1 was complexed with the nuclear matrix. Confirmed by Western blotting, curcumin treatment resulted in a down-regulation of hnRNP A2/B1 expression. An altered distribution of hnRNP A2/B1 with the nuclear matrix was observed in immunofluorescence assays. Laser confocal microscopy- showed that hnRNP A2/B1 colocalized with apoptosis-related molecules, including Bax, Bcl-2, Fas and p53, with different patterns before and after curcumin treatments. Our study showed that expression level and the distribution of hnRNP A2/B1, a nuclear matrix protein, were altered by curcumin treatments and mought be involved in the process of apoptosis in MG63 cells.