运用CRISPR-Cas9功能基因组学筛查技术探索肝癌治疗新策略

Hepatocellular carcinoma (HCC) is one of the most frequent malignancies with complicated mechanisms of pathogenesis. The development and progression of liver cancer are mediated by a lot of functional genes and several different risk factors. Sorafenib is a multikinase inhibitor that is approved as the standard therapy for advanced HCC patients. However, sorafenib provides only limited response rate for patients with advanced HCC. It is therefore urgent to identify potential therapeutic targets for HCC. Here, we attempt to identify novel treatment strategy for HCC by functional genetic screens based on CRISPR-Cas9 technology. Cell division cycle 7 (CDC7) which is required for proliferation of HCC cells was identified. We observed that CDC7 inhibition with XL413 selectively induced senescence in p53 mutant liver cancer cells. Based on these findings, we provide the hypothesis that is it possible to induce senescence first and then to screen for compounds that selectively kill the senescent cells (one-two punch model). By a GPCR compound screen, we found that sertraline could selectively kill the senescent cells by suppressing mTOR signaling. In the further study, we are planning to explore the mechanism why CDC7 inhibitor can selectively induce senescence in p53 null or mutant cancer cells. The mechanisms why mTOR inhibitor can specifically induce apoptosis in senescent cells will be also revealed by further analyzing the crosstalk between the relevant signaling. In addition, we will investigate the feasibility and rationality of one-two punch model using xenografts and genetic models. This study may provide a novel and promising therapeutic approach to the treatment of HCC.

肝细胞癌是一种多基因参与、多因素介导、病理机制复杂的恶性肿瘤。在临床，作为进展期肝癌标准疗法的索拉菲尼仅能获得较低的治疗反应性，寻找安全有效的治疗策略已成为肝癌研究领域的热点。本课题拟采用CRISPR-Cas9功能基因组学筛查技术探索肝癌治疗新策略。在前期的高通量筛选中我们发现CDC7对于肝癌细胞的生长具有调节作用。抑制CDC7能特异性地促进p53突变肝癌细胞衰老。在此基础上，我们提出首先诱导肿瘤细胞衰老再特异性诱导衰老细胞凋亡的治疗理念（one-two punch模型）。通过高通量化合物筛查，我们发现sertraline可以通过抑制mTOR信号通路特异性诱导衰老细胞凋亡。在后续研究中，我们将系统研究CDC7抑制剂选择性诱导p53突变肝癌细胞衰老以及mTOR抑制剂特异性诱导衰老细胞凋亡的分子机制，同时在动物水平探索该治疗策略的可行性。本研究有望为肝癌的治疗提供新的实验依据。

肝细胞癌是一种多基因参与、多因素介导、病理机制复杂的恶性肿瘤。在临床，作为进展期肝癌标准疗法的索拉菲尼仅能获得较低的治疗反应性，寻找安全有效的治疗策略已成为肝癌研究领域的热点。本课题采用CRISPR-Cas9功能基因组学筛查技术探索肝癌治疗新策略。在高通量功能基因筛选中，我们发现CDC7对于肝癌细胞的生长具有调节作用。抑制CDC7能特异性地促进p53突变肝癌细胞衰老。在此基础上，我们提出首先诱导肿瘤细胞衰老再特异性诱导衰老细胞凋亡的治疗理念（one-two punch模型）。通过高通量化合物筛查，我们发现sertraline可以通过抑制mTOR信号通路特异性诱导衰老细胞凋亡。随后，我们系统研究CDC7抑制剂选择性诱导p53突变肝癌细胞衰老以及mTOR抑制剂特异性诱导衰老细胞凋亡的分子机制，同时在动物水平验证了该治疗策略的可行性。该研究创新性地提出先特异诱导肿瘤细胞衰老，再特异清除衰老肿瘤细胞的"One-two punch"分步式肝癌精准治疗模式，为肝癌精准治疗提供了新思路。