Qi Defeng, Hu Yuan, Li Jinhui, Peng Tao, Su Jialin, He Yun, Ji Weidong
Department of Urology, Minimally Invasive Surgery Center, The First Affiliated Hospital of Guangzhou Medical University, Guangdong Provincial Key Laboratory of Urology, Guangzhou, China.
School of public health, Sun Yat-sen University, Guangzhou, China.
PLoS One. 2015 Apr 22;10(4):e0122977. doi: 10.1371/journal.pone.0122977. eCollection 2015.
Hyperthermia as an anticancer method has been paid increasing attention in recent years. Several studies have shown that hyperthermia can kill tumor cells by inducing apoptosis. However, the underlying molecular mechanisms of hyperthermia-induced apoptosis are largely unknown. To investigate the effects and molecular mechanism of hyperthermia on the apoptosis in renal carcinoma 786-O cells, we firstly examined apoptosis and Ku expression in 786-O cell line treated with heat exposure (42°C for 0-4 h). The results showed that hyperthermia induced apoptosis of 786-O cells, and suppressed significantly Ku80 expression, but not Ku70 expression. Next, we knock-down Ku80 in 786-O cells, generating stable cell line 786-O-shKu80, and detected apoptosis, cell survival and cell cycle distribution. Our data showed higher apoptotic rate and lower surviving fraction in the stable cell line 786-O-shKu80 compared with those in control cells, exposed to the same heat stress (42°C for 0-4 h). Moreover, the results also showed suppression of Ku80 led to G2/M phase arrest in the stable cell line 786-O-shKu80 following heat treatment. Together, these findings indicate that Ku80 may play an important role in hyperthermia-induced apoptosis and heat-sensitivity of renal carcinoma cells through influencing the cell cycle distribution.
近年来，热疗作为一种抗癌方法越来越受到关注。多项研究表明，热疗可通过诱导细胞凋亡来杀死肿瘤细胞。然而，热疗诱导细胞凋亡的潜在分子机制在很大程度上尚不清楚。为了研究热疗对肾癌细胞786-O细胞凋亡的影响及其分子机制，我们首先检测了热暴露（42°C处理0 - 4小时）的786-O细胞系中的细胞凋亡和Ku表达情况。结果显示，热疗诱导了786-O细胞的凋亡，并显著抑制了Ku80的表达，但未抑制Ku70的表达。接下来，我们在786-O细胞中敲低Ku80，构建稳定细胞系786-O-shKu80，并检测细胞凋亡、细胞存活及细胞周期分布情况。我们的数据显示，与对照细胞相比，在相同热应激（42°C处理0 - 4小时）条件下，稳定细胞系786-O-shKu80具有更高的凋亡率和更低的存活分数。此外，结果还表明，在热处理后，稳定细胞系786-O-shKu80中Ku80的抑制导致了G2/M期阻滞。综上所述，这些发现表明Ku80可能通过影响细胞周期分布，在热疗诱导的肾癌细胞凋亡和热敏感性中发挥重要作用。
