Division of Life Sciences, College of Life Sciences and Bioengineering, University of Incheon, Incheon, Republic of Korea.
J Cell Physiol. 2013 Jul;228(7):1496-505. doi: 10.1002/jcp.24305.
The clinical efficacy of many chemotherapeutic agents has been reduced due to the development of drug resistance. In this article, we aimed to validate gossypol, a natural BH3 mimetic found in cottonseeds, as a potential therapeutic to overcome multidrug resistance (MDR). Gossypol was found to retain its efficacy in v-Ha-ras-transformed NIH 3T3 cells that overexpressed P-glycoprotein (Ras-NIH 3T3/Mdr), which was similar to the efficacy observed in their parental counterparts (Ras-NIH 3T3). A rhodamine assay revealed that the alteration of MDR activity did not contribute to the cytotoxic effect of gossypol. Gossypol caused a G2 /M arrest by the induction of p21(Cip1) and the down-regulation of p27(Kip1) expression in Ras-NIH 3T3 cells, whereas no significant G2 /M arrest was exhibited in Ras-NIH 3T3/Mdr cells. Surprisingly, a 48-h treatment with gossypol induced apoptotic cell death in Ras-NIH 3T3 cells; however, gossypol induced both apoptosis and necrosis in Ras-NIH 3T3/Mdr cells, as determined with flow cytometry analysis. More notably, gossypol preferentially induced autophagy in Ras-NIH 3T3 cells but not in Ras-NIH 3T3/Mdr cells. Coimmunoprecipitation and flow cytometric analysis revealed that gossypol-induced autophagy is independent of the dissociation of Beclin 1 from Bcl-2 in Ras-NIH 3T3 cells. Taken together, these results suggest that the antiproliferative activity of gossypol appears to be due to cell-cycle arrest at the G2 /M phase, with the induction of apoptosis in Ras-NIH 3T3 cells. In addition, defective autophagy might contribute to apoptotic and necrotic cell death in response to gossypol in Ras-NIH 3T3/Mdr cells.
由于耐药性的发展,许多化疗药物的临床疗效已经降低。在本文中,我们旨在验证棉籽中发现的天然 BH3 类似物——黄烷醇,作为一种克服多药耐药性(MDR)的潜在治疗方法。研究发现,黄烷醇在过表达 P 糖蛋白(Ras-NIH 3T3/Mdr)的 v-Ha-ras 转化的 NIH 3T3 细胞中仍保持其疗效,这与在其亲本细胞(Ras-NIH 3T3)中观察到的疗效相似。罗丹明测定表明,MDR 活性的改变与黄烷醇的细胞毒性作用无关。黄烷醇通过诱导 p21(Cip1)的表达和下调 p27(Kip1)的表达,导致 Ras-NIH 3T3 细胞发生 G2/M 期阻滞,而在 Ras-NIH 3T3/Mdr 细胞中则没有明显的 G2/M 期阻滞。令人惊讶的是,用黄烷醇处理 48 小时后,诱导 Ras-NIH 3T3 细胞发生凋亡性细胞死亡;然而,用黄烷醇处理 Ras-NIH 3T3/Mdr 细胞,既诱导凋亡又诱导坏死,通过流式细胞术分析可以确定。更值得注意的是,黄烷醇优先诱导 Ras-NIH 3T3 细胞发生自噬,但不诱导 Ras-NIH 3T3/Mdr 细胞发生自噬。共免疫沉淀和流式细胞术分析表明,黄烷醇诱导的自噬与 Ras-NIH 3T3 细胞中 Beclin 1 从 Bcl-2 解离无关。综上所述,这些结果表明,黄烷醇的抗增殖活性似乎是由于 Ras-NIH 3T3 细胞的细胞周期阻滞在 G2/M 期,并诱导细胞凋亡。此外,自噬缺陷可能导致 Ras-NIH 3T3/Mdr 细胞对黄烷醇的凋亡和坏死性细胞死亡。