蛇床子素通过抑制SIRT1的表达增强阿霉素对p53野生型前列腺癌细胞的凋亡诱导活性

目的:探讨中药活性成分蛇床子素对阿霉素抗前列腺癌作用的影响及机制。方法:MTT法检测前列腺癌细胞系LNCaP在阿霉素和蛇床子素处理下的细胞活力。Western blot实验检测阿霉素和蛇床子素对LNCaP细胞中沉默信息调节因子1(SIRT1)、p53、乙酰化p53和Puma的表达水平、细胞色素C的释放水平及caspase-9和caspase-3活化水平的影响。流式细胞术检测阿霉素和蛇床子素对LNCaP细胞凋亡的影响。结果:蛇床子素联合治疗能明显提高阿霉素对p53野生型前列腺癌细胞系LNCaP的杀伤力。蛇床子素处理能显著抑制LNCaP细胞中SIRT1的表达,转染SIRT1过表达质粒后,蛇床子素、阿霉素联合治疗对LNCaP细胞的杀伤力受到显著抑制(P0.05)。蛇床子素联合阿霉素显著升高LNCaP细胞p53蛋白的表达水平和乙酰化水平,转染p53 si RNA后,蛇床子素对阿霉素的协同作用明显减弱。蛇床子素联合阿霉素显著诱导LNCaP细胞细胞色素C从线粒体释放到细胞质中,增强细胞中的caspase-9及下游caspase-3的活性并诱导细胞发生凋亡。结论:蛇床子素通过下调前列腺癌LNCaP细胞中SIRT1的表达促进阿霉素诱导的p53依赖的细胞凋亡。

Osthole enhances doxorubicin-induced apoptosis in p53-wildtype prostate cancer cells by down-regulating SIRT1 expression

AIM: To investigate the effect and mechanism of osthole on increasing the cytotoxicity of doxorubicin (DOX) to prostate cancer cells. METHODS: MTT assay was performed to evaluate the viability of LNCaP cells treated with osthole and DOX. The protein expression of silent information regulator 1 (SIRT1), p53, acetylated p53 and Puma, as well as release of cytochrome C and activation of caspase-9 and caspase-3 in the LNCaP cells treated with osthole and DOX were determined by Western blot. The apoptosis of the LNCaP cells treated with osthole and DOX was analyzed by flow cytometry. RESULTS: Osthole significantly increased the cytotoxicity of DOX against p53-wildtype prostate cancer cell line LNCaP. Osthole significantly inhibited the expression of SIRT1 in the LNCaP cells. Transfection with SIRT1 plasmid decreased the cytotoxicity of osthole and DOX co-treatment against LNCaP cells. Combination with osthole and DOX significantly induced the over-expression and acetylation of p53. Transfection with p53 siRNA significantly decreased the synergistic effect of osthole on cytotoxicity of DOX-treated LNCaP cells. Combination with osthole and DOX significantly induced the release of cytochrome C into the cytoplasm from mitochondria, followed by activation of caspase-9 and its downstream molecule caspase-3, thus leading to cell apoptosis in the LNCaP cells. CONCLUSION: Osthole promotes the p53-dependent apoptosis in DOX-treated prostate cancer LNCaP cells by down-regulating the expression of SIRT1.