Hes1靶向调控IGF1R信号通路诱导肝癌放疗抵抗的作用机制研究

Radioresistance is one of the main reasons for the treatment failure in hepatocellular carcinoma (HCC). Transcription factor Hes1 has been shown to be closely related to the radiosensitivity of various tumors. However, the role of it on the radiosensitivity of HCC is hardly known. Previously we have established several radioresistant HCC cell lines and then screen the resistance-related factor Hes1 by Gene chip, which is highly expressed in both HCC cell lines and tissue samples. Overexpression of Hes1 could induce cell radioresistance in HCC. Further studies found that Hes1 could directly target IGF1R and activate downstream related signaling pathways. Accordingly, we hypothesized that the transcription factor Hes1 induces cell radioresistance by targeting IGF1R and activating radioresistance related signaling pathways. This study intends to elucidate the effect of Hes1 on the radioresistance of HCC and its specific regulation mechanism through in vitro and in vivo experiments. We would simultaneously investigate the relationship between Hes1 and IGF1R as well as the sensitivity and prognosis by detecting HCC tissue samples and collecting clinical data of HCC patients. The completion of this project will clarify the status and potential clinical significance of Hes1 on the radiosensitivity in HCC, which may provide a new strategy for the doctors making individualized radiotherapy plans.

放疗抵抗是肝细胞肝癌（HCC）治疗失败的主要原因之一。转录因子Hes1已被证实与多种肿瘤放疗敏感性密切相关，但其在HCC放疗敏感性中的作用尚不明确。前期我们通过建立耐放疗细胞株及基因芯片筛选发现Hes1是HCC放疗抵抗相关因子，其在HCC细胞株和组织标本中高表达；上调Hes1的表达可以促进HCC细胞放疗抵抗；进一步发现IGF1R是其下游靶基因，可以上调其表达并激活下游相关信号通路。据此，我们推测转录因子Hes1通过上调IGF1R基因开放放疗抵抗相关信号通路从而降低HCC细胞放疗敏感性。本项目拟通过体外和体内实验阐明Hes1介导HCC放疗抵抗的分子作用机制，并探索临床干预的可能性。同时，我们将通过HCC组织标本和收集临床资料，明确Hes1和IGF1R的表达及与放疗敏感性和预后相关性。本项目的完成将明确Hes1在HCC放疗敏感性中的地位和潜在临床意义，为临床制定个体放疗计划提供新思想。

放疗抵抗是肝细胞肝癌(HCC)治疗失败的主要原因之一。转录因子Hes1已被证实与多种肿瘤放疗敏感性密切相关，但其在HCC放疗敏感性中的作用尚不明确。本实验中我们首先建立了辐射抵抗肝癌细胞株，接着利用基因芯片技术筛选出肝癌辐射抵抗因子Hes1。通过qRT-PCR发现Hes1在肝癌组织标本和细胞株中表达明显上调；通过体外功能实验（平板克隆、免疫荧光、免疫印记等）证实过表达Hes1可促进肝癌细胞辐射抵抗，反之，敲除Hes1可降低肝癌细胞辐射抵抗。为进一步探寻Hes1引起肝癌辐射抵抗的具体分子机制，通过生物信息学预测分析发现Hes1与IGF1R启动子区域有结合位点，进一步通过双荧光素酶报告系统证实IGF1R为Hes1下游调控的靶基因。那IGF1R是否为Hes1诱导肝癌辐射抵抗的功能性靶基因？为了证实这一点，通过回复实验证实IGF1R为Hes1下游直接调控的一个功能性靶基因。接着继续寻找IGF1R下游信号通路，通过生物信息学预测及本实验研究结果证实，过表达Hes1联合辐射后PI3K/Akt/mTOR信号通路被激活，据此，我们推测转录因子Hes1通过上调IGF1R基因开放PI3K/Akt/mTOR信号通路从而降低HCC细胞放疗敏感性。后续进一步通过一系列功能实验及回复实验证实Hes1通过转录调控IGF1R表达上调继而激活PI3K/Akt/mTOR信号通路增强肝癌辐射抵抗。同时，我们将通过HCC组织标本和收 集临床资料，明确Hes1和IGF1R的表达及与放疗敏感性和预后相关性。本项目的完成明确了Hes1在HCC放疗敏感性中的地位和潜在临床意义，为临床制定个体放疗计划提供新思想。