JARID1C依赖去甲基化酶活性抑制HIF2α靶基因表达和肾癌增殖的机制研究

Epigenetic dysregulation play an important role in the pathogenesis of renal cell carcinoma; JARID1C is a histone H3 lysine 4 (H3K4me3) demethylase. Through whole-genome Exon sequencing found about 4% kidney cancer specimens contain JARID1C mutations. Previous studies showed that JARID1C inhibits the proliferation of renal carcinoma cells, but the molecular mechanisms of JARID1C inhibition of tumor cell proliferation remains unclear. By using TALEN technology, we knockout JARID1C gene and mutated JARID1C H514A and established the gene targeting cell,which demethylase activity was mutated; by immunoprecipitation experiments prove that JARID1C and HIF2α binding together; by chromatin immunoprecipitation confirmed that HIF2α recruitment JARID1C to GDF15 promoter, inhibiting its expression through decreasing the promoter H3K4Me3 level; Nude mouse tumorigenicity experiments prove that JARID1C inhibits tumor growth depending on its demethylase activity, which will provide a new drug target for renal cancer therapy.

表观遗传的改变在肾癌的发病中发挥重要作用；JARID1C是组蛋白4赖氨酸3甲基化(H3K4me3)的去甲基化酶。全基因组外显子测序发现肾癌标本中4%的JARID1C基因发生突变。前期研究表明JARID1C抑制肾癌细胞的增殖，但JARID1C抑制肿瘤细胞增殖的分子机制仍不清楚。本项目中采用TALEN核酶技术敲除JARID1C；同时基因打靶建立JARID1C-H514A突变其去甲基化酶活性的细胞株；通过免疫沉淀实验证明HIF2α与JARID1C相互结合; 通过染色质免疫沉淀证明HIF2α招募JARID1C到GDF15的启动子上抑制其表达依赖于其H3K4Me3去甲基化酶活性; 通过裸鼠成瘤实验证明JARID1C抑制肿瘤增值依赖于其去甲基化酶活性。从而阐明JARID1C结合HIF2α抑制其靶基因表达和JARID1C依赖其去甲基化酶抑制肾癌发展的分子机制,为将来的肿瘤治疗提供新靶点。

表观遗传的改变在肾癌的发病中发挥重要作用；JARID1C是组蛋白4赖氨酸3甲基化(H3K4me3)的去甲基化酶。 基于之前全基因组外显子测序发现肾癌标本中有4%的JARID1C基因发生突变，及前期研究工作表明JARID1C抑制肾癌细胞的增殖，但JARID1C抑制肿瘤细胞增殖的分子机制仍不清楚。因此本项目首先采用TALEN核酶技术敲除JARID1C；同时基因打靶建立JARID1C-H514A突变其去甲基化酶活性的细胞株；构建了敲除JARID1C和突变JARID1C去甲基化酶活性的细胞系，其次通过免疫沉淀实验证明HIF2α与JARID1C相互结合; 通过染色质免疫沉淀证明HIF2α招募JARID1C到GDF15的启动子上并抑制其表达依赖于其H3K4Me3去甲基化酶活性; 最终通过裸鼠成瘤实验证明JARID1C抑制肿瘤增值依赖于其去甲基化酶活性。项目阐明JARID1C结合HIF2α抑制其靶基因表达和JARID1C依赖其去甲基化酶抑制肾癌发展的分子机制,为将来的肿瘤治疗提供新靶点。