Ca2+/S100A2/p53介导KCa3.1钾通道调控肝癌增殖与凋亡的分子机制研究

Hepatocellular carcinoma is the third leading cause of cancer-related mortality, and leads to 110,000 people deaths every year in China. The current treatment of hepatocellular carcinoma is not ideal, so it is necessary to look for novel targets to treat hepatocellular carcinoma. KCa3.1 potassium channel is a newly discovered membrane potassium channel protein, its carrying the middle-conductance calcium-activated potassium currents is involved in the regulation of intracellular calcium homeostasis.Our preliminary experimental results found that KCa3.1 potassium channel was highly expressed in hepatocellular carcinoma cells. KCa3.1 potassium channel blockers can inhibit the proliferaton of hepatocellular carcinoma cells and induce its apoptosis, suggesting that blocking KCa3.1 potassium channel can treat hepatocellular carcinoma, but its molecular mechanism is largely unclear. Accordingly, we hypothesize that KCa3.1 potassium channel regulates proliferation and apoptosis of hepatocellular carcinoma cells by activating Ca2+/S100A2/p53 pathway, and might be a new target for hepatocellular carcinoma treatment. The project will employ Patch clamp, Confocal laser scanning microscopy, Immunoprecipitation, RNA interference, Western blot, etc to confirm the antitumor effects of blocking KCa3.1 channel, and uncover the molecular mechanism of KCa3.1 potassium channels in the regulation of proliferation and apoptosis of hepatocellular carcinoma cells, and provide novel targets and strategy for the clinical treatment of hepatocellular carcinoma, and display important scientific significance and promisting application potential in clinics.

肝癌占我国癌症死亡率的第三位，每年死亡11万人，然而目前临床上对于肝癌的治疗很不理想，因此亟需寻找肝癌防治的新靶点。KCa3.1钾通道是新发现的膜钾通道蛋白，它所形成的中电导钙激活钾电流参与了细胞内钙稳态的调节。在前期研究中我们发现KCa3.1钾通道在肝癌细胞中高表达，特异性地阻断KCa3.1钾通道可抑制肝癌细胞增殖、诱导其调亡，提示抑制KCa3.1钾通道具有抗肝癌的作用，但其确切分子机制尚不清楚。据此我们提出假设："KCa3.1钾通道通过Ca2+/S100A2/p53途经调控肝癌细胞增殖与调亡过程，是肝癌治疗的新靶点"。本项目拟运用膜片钳、激光共聚焦显微镜、免疫共沉淀、RNA干扰、蛋白杂交等手段从细胞、整体水平验证阻断KCa3.1钾通道的肝癌治疗作用，并进一步阐明KCa3.1钾通道调控肝癌细胞增殖、凋亡的的分子机制，为临床上肝癌的治疗提供新靶点和新策略，具有重要的科学意义和临床应用价值。

肝癌占我国癌症死亡率的第三位，每年死亡11 万人，然而目前临床上对于肝癌的治疗很不理想，因此亟需寻找肝癌防治的新靶点。通过本项目研究我们发现KCa3.1钾通道特异性阻断剂TRAM-34可以抑制HepG2细胞增殖，并诱导HepG2细胞凋亡。此外，KCa3.1钾通道阻断剂TRAM-34还可抑制HepG2细胞的迁移，这些结果提示KCa3.1钾通道阻断剂可用于肝癌的治疗。进一步研究揭示TRAM-34可以引起HepG2细胞内ROS的增加，并促使细胞内p53由胞浆转移至胞核。KCa3.1钾通道siRNA同样可以抑制HepG2细胞增殖，诱导HepG2细胞凋亡，并抑制HepG细胞的迁移。通过本项目的研究，揭示了阻断KCa3.1钾通道可以抑制肝癌细胞增殖和迁移，促进肝癌细胞凋亡，提示KCa3.1钾通道阻断剂是肝癌治疗的新靶点，为临床肝癌的防治提供了新思路。本项目取得了预期的研究成果。参加国内学术会议两次，培养研究生2名。