Akt-mTOR通路调控SD大鼠大分割放疗后肝再生的机制研究

Liver function damage after radiotherapy for hepatocellular carcinoma (HCC) is the bottleneck restricting the application of radiotherapy for HCC. Liver regeneration contributes to the recovery of liver function, which has been extensively studied in partial hepatectomy and ALPPS, etc. However, the related studies and mechanisms of liver regeneration after radiotherapy have rarely been reported. .Our previous results found that mRNA of Akt and mTOR were significantly highly expressed in HCC patients with liver regeneration after radiotherapy comparing to those without regeneration after radiotherapy. It was also verified that mTOR inhibitor could reduce the clonal formation ability of liver normal cell lines after radiotherapy in vitro experiments. Therefore, we hypothesized that the Akt-mTOR signaling pathway might regulate liver regeneration after radiotherapy..We aim to establish an animal model of liver regeneration after liver fractionated irradiation in Sprague-Dawley rats. Animal models were treated with Akt-mTOR signaling pathway inhibitor (Akt inhibitor, mTOR inhibitor) and pathway agonist (carbamazepine) in vivo experiment. Using RT-PCR, Western Blot and other experimental techniques, the molecular mechanism of Akt-mTOR signaling pathway regulating liver regeneration after radiotherapy were investigated at mRNA, total protein and phosphorylation level. This study may provide therapeutic targets for clinical prevention and treatment of liver function damage and liver regeneration after radiation.

肝细胞癌放射治疗后肝功能损害是制约肝癌放疗应用的瓶颈。肝再生有助于肝功能恢复，其在肝部分切除和ALPPS等得到广泛研究，然而放射治疗后肝细胞再生相关研究及机制鲜有报道。.课题组前期发现Akt、mTOR基因mRNA高表达于肝癌放疗后肝细胞再生组织中；细胞体外实验mTOR抑制剂降低放疗后正常肝细胞株的克隆形成能力。因此我们提出假说：Akt-mTOR信号通路调控肝脏放疗后的肝细胞再生。.为验证此假说，拟建立大鼠肝右叶大分割放疗-肝左叶再生的动物模型，应用Akt-mTOR信号通路抑制剂（Akt inhibitor，mTOR inhibitor）和通路激动剂（卡马西平）干预放疗-肝再生动物模型；通过RT-PCR和Western Blot等实验技术，在mRNA、总蛋白水平及磷酸化水平，探讨Akt-mTOR信号通路调控放疗后肝细胞再生的机制，为临床防治放射性肝功能损害和肝再生提供治疗靶点。

放射性肝损伤是制约肝癌放疗的主要限制性因素之一。针对放射性肝损伤-肝再生这一关键的临床问题，开展临床基础转化研究。课题组发现：放疗前的肝功能状态不仅关系到患者的生存时间，还是放射性肝损伤和放疗耐受剂量的主要影响因素，通过采集多中心的临床肝癌放疗数据，基于肝功能、肿瘤状态、体力评分，首次建立了肝癌放疗新分期。课题组发现放射性肝再生有望改善放疗引起的肝损伤，其中谷丙转氨酶（ALT）和剩余标准肝剂量（SVs20）是放射性肝再生的关键预后指标；并提出正常肝保护的靶区勾画（苏氏靶区），显著的减少了肝损伤的发生并可减轻其严重程度。另外，收集到临床肝损伤和肝再生组织标本，并建立了SD大鼠放射性肝损伤-肝再生的动物模型（不同体积和剂量照射：15Gy+1/2V，15Gy+2/3V，25Gy+1/2V，25Gy+2/3V）。通过蛋白组学-全转录组学检测，发现PI3K/AKT/mTOR通路在放射性肝损伤-肝再生中发挥调控作用，并通过Western-Blot等验证了分子作用机制，同时发现卡马西平有望成为放射性肝再生潜在用药。