长链非编码核苷酸LINC00312促进雄激素受体突变体AR-v7的产生及其在前列腺癌进展和耐药中的作用

Enzalutamide (Enz, 恩杂鲁胺) has been approved to treat castration resistant prostate cancer. Accumulating evidences suggest that androgen receptor (AR, 雄激素受体) variant AR-v7 plays significant role in the development of Enz resistance. Therefore, understanding the mechanisms by which AR-v7 is produced is of importance to improve current therapeutic strategies towards PCa patients. By establishing Enz resistant cell lines, applicant identified that RNA-processing associated lncRNA called LNC00312 and its related certain splicing factor were recruited to the pre-mRNA AR, leading to the alternative splicing of pre-mRNA AR to AR-v7. Overexpression of LNC00312 not only boosted AR-v7 expression but also caused Enz resistance. On the contrary, LNC00312 depletion in Enz resistant cells re-sensitized cells to Enz treatment. Taking together, we hypothesize that: LNC00312 promotes the splicing of pre-mRNA AR to AR-v7 and is involved in the development of Enz resistance. This project is planned to investigate the biological functions of LNC00312 in prostate cancer and to explore the underlying mechanism by which LNC00312 promotes AR-v7.

恩杂鲁胺用于治疗去势抵抗性前列腺癌。大量临床数据表明，雄激素受体（AR）的突变体AR-v7在恩杂鲁胺耐药过程中发挥重要作用。因此，了解AR-v7产生的分子机理对于前列腺癌患者的治疗有重要指导意义。申报人通过构建恩杂鲁胺耐药细胞株，发现跟RNA合成相关的长链非编码核苷酸LNC00312通过结合相关剪切因子并富集到AR的pre-mRNA上，促进其选择性剪切产生AR-v7，过表达LNC00312不仅显著提高AR-v7的表达，同时也明显降低前列腺癌细胞对恩杂鲁胺的敏感性。相反，降低LNC00312能够提高耐药细胞株对恩杂鲁胺的敏感性。据此，我们提出假设：LNC00312能够促进AR的pre-mRNA剪切产生AR-v7，进而导致恩杂鲁胺耐药。本项目拟通过研究LNC00312在前列腺癌中的生物学功能并探索LNC00312促进AR-v7的分子机理。

前列腺癌是常见的男性肿瘤。恩杂鲁胺是治疗去势抵抗性前列腺癌的抗雄药物，但仅能延长病人约5个月生命进而产生药物抵抗。已有研究表明雄激素受体变异体与前列腺癌抗雄抵抗紧密关联。本项目发现长链非编码核苷LNC00312在恩杂鲁胺处理过程中富集到AR mRNA前体，促使其剪切产生ARv7和新型雄激素受体ARv33，导致前列腺癌细胞恩杂鲁胺耐药。ARv33是具两个exon 3的全长AR，经mRNA和蛋白定量定性分析，其存在于恩杂鲁胺耐药细胞和高级别前列腺癌样本中。ARv33可与ARv7相互结合，且结合能力强于AR，ARv33/ARv7复合物可让前列腺癌细胞获得较高的恩杂鲁胺耐药性。ARv33的产生不是源于恩杂鲁胺耐药细胞AR基因的重组，而是源于两条AR mRNA前体的反式剪切。体内外实验均证明靶向ARv33可以抑制恩杂鲁胺耐药肿瘤的进展，是潜在的治疗靶点。