Department of Obstetrics and Gynecology, General Hospital of the People's Liberation Army, Chengdu Military Region, P.R. China.
Department of Obstetrics and Gynecology, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, P.R. China.
Int J Oncol. 2014 Apr;44(4):1401-9. doi: 10.3892/ijo.2014.2301. Epub 2014 Feb 14.
Notch signaling is implicated in ovarian cancer tumorigenesis and inhibition of Notch signaling with γ-secretase inhibitor DAPT resulted in reduction of tumor cell viability and induction of apoptosis in ovarian cancer cells. This study investigated whether DAPT has the same effect on ovarian cancer cells that are resistant to cisplatin and the underlying molecular events. Ovarian cancer cell lines resistant to cisplatin were treated with DAPT, cisplatin or combination for cell viability MTT, flow cytometric cell cycle, ELISA apoptosis and colony formation assays. qRT-PCR and western blotting were used to detect gene expressions. We found that pretreatment of ovarian cancer cisplatin-resistant cell lines with DAPT for 24 h and then with cisplatin for 72 h showed a synergistic antitumor activity in these cell lines, while cisplatin treatment and then addition of DAPT just showed an additive or antagonistic effects on these cisplatin-resistant ovarian cancer cells. Moreover, pretreatment of ovarian cancer cell lines with DAPT and then with cisplatin also inhibited tumor cell colony formation capacity, arrested tumor cells at G2 phase of the cell cycle and induced apoptosis. The cell cycle and apoptosis-related genes, such as cyclin B1, Bcl-2 and caspase-3, were also modulated by the treatment. Pretreatment of ovarian cancer cell lines with DAPT and then with cisplatin downregulated Notch1 and Hes1 expression dose- and time-dependently. The current data demonstrate that DAPT pretreatment was able to sensitize cisplatin-resistant human ovarian cancer cells to cisplatin by downregulation of Notch signaling.
Notch 信号通路与卵巢癌的肿瘤发生有关，用 γ-分泌酶抑制剂 DAPT 抑制 Notch 信号通路会导致肿瘤细胞活力降低，并诱导卵巢癌细胞凋亡。本研究旨在探讨 DAPT 是否对顺铂耐药的卵巢癌细胞具有相同的作用，以及其潜在的分子事件。用 DAPT、顺铂或两者联合处理对顺铂耐药的卵巢癌细胞系，通过 MTT 法检测细胞活力、流式细胞术检测细胞周期、ELISA 法检测细胞凋亡和集落形成实验。用 qRT-PCR 和 Western blot 检测基因表达。我们发现，用 DAPT 预处理顺铂耐药的卵巢癌细胞系 24 h 后再用顺铂处理 72 h，可在这些细胞系中显示协同的抗肿瘤活性，而先用顺铂处理再加入 DAPT 仅对这些顺铂耐药的卵巢癌细胞表现出相加或拮抗作用。此外，用 DAPT 预处理卵巢癌细胞系，然后再用顺铂处理，也抑制了肿瘤细胞集落形成能力，使肿瘤细胞在细胞周期的 G2 期停滞，并诱导凋亡。细胞周期和凋亡相关基因，如细胞周期蛋白 B1、Bcl-2 和 caspase-3，也被这种治疗方式所调节。用 DAPT 预处理卵巢癌细胞系并随后用顺铂处理可剂量和时间依赖性地下调 Notch1 和 Hes1 的表达。目前的数据表明，DAPT 预处理能够通过下调 Notch 信号通路使顺铂耐药的人卵巢癌细胞对顺铂敏感。
