β-arrestin2介导的PKM可变剪接调控前列腺癌多西他赛耐药的作用研究

Chemotherapeutic resistance is an important cause of treatment failure in castration resistant prostate cancer (CRPC) therapy. How to enhance the sensitivity and reverse the drug resistance of docetaxel in CRPC patients remains a severe challenge for clinical treatment to date. In our previous study, we found that the tolerance of CRPC cells with β-arrestin2 overexpression to docetaxel was significantly increased, which was related to β-arrestin2-induced increased expression of PKM2. Heterogeneous nuclear ribonucleoprotein (hnRNAP)-mediated alternative splicing is a key mechanism for the regulation of PKM2 expression, we had confirmed that hnRNP is involved in the regulation of β-arrestin2-induced PKM2 expression, suggesting that β-arrestin2 may promote the docetaxel resistance of CRPC cells via modulating hnRNP-mediated alternative splicing of PKM, but its exact role and underlying mechanism still need further research. Therefore, based on our previous results, this project was designed to study the role and mechanism of β-arrestin2-mediated PKM alternative splicing in the regulation of docetaxel resistance in CRPC through cell and animal experiments, as well as clinical samples, thus to reveal the possible molecular mechanism of CRPC docetaxel resistance and provide new experimental basis for its clinical treatment.

去势抵抗型前列腺癌（CRPC）的化疗耐药是导致其治疗失败的重要原因，如何增强CRPC的多西他赛敏感性和逆转耐药仍然是目前临床治疗所面临的严峻挑战。我们前期发现β-arrestin2过表达的CRPC细胞对多西他赛的耐药性明显增加，且与β-arrestin2诱导的PKM2的表达增加有关。核不均一核糖核蛋白（hnRNAP）介导的可变剪接是调控PKM2表达的关键机制，我们前期初步证实hnRNP参与了β-arrestin2诱导的PKM2表达调控，提示β-arrestin2可能通过调控hnRNP介导的PKM可变剪接从而促进了CRPC细胞的多西他赛耐药，但其具体机制仍需进一步的研究。因此，本项目拟进一步通过细胞、动物实验以及临床样本，对β-arrestin2介导的PKM可变剪接在CRPC多西他赛耐药过程中的作用及机制进行深入研究，从而揭示CRPC多西他赛耐药的可能分子机制并为其临床治疗提供新的实验依据。

前列腺癌在男性的致死性癌症中高居第二位，是导致老年男性死亡的最主要的恶性肿瘤之一。早期局限性前列腺癌在采用根治性前列腺切除术或放射治疗后可以达到治愈的目的，而局部晚期和转移性前列腺癌的往往预后不良，并最终进展为去势抵抗型前列腺癌（castration resistant prostate cancer, CRPC）。由于其发病及进展机制不明，目前国际上仍缺乏有效控制CRPC的药物和治疗措施。化疗是CRPC的重要治疗手段，其可以延长CRPC患者的生存时间，控制疼痛及提高活质量。尽管以多西他赛为基础的化疗方案效显著，但是前列腺癌转移瘤对化疗药物选择性低且容易产生耐药，极大地影响了治疗效果并导致治疗失败。如何逆转化疗耐药，或增强多西他赛的敏感性仍是目前研究主要方向之一。我们的前期研究发现G蛋白偶联受体的负性调控蛋白β-arrestin2介导的丙酮酸激酶PKM可变剪接可能是其促进CRPC细胞对多西他赛产生耐药的一种重要机制，但其具体作用及机制仍不清楚。因此，本项目通过细胞、动物实验和临床样本，结合公共数据库相关数据分析，对β-arrestin2介导的PKM可变剪接在CRPC多西他赛耐药过程中的作用及机制进行了深入研究，证实β-arrestin2和PKM2可以促进CRPC细胞的多西他赛耐药性，并且证实β-arrestin2可以通过调控hnRNP A1/A2的表达而调控PKM的可变剪接即促进PKM2亚型的生成，继而促进了CRPC细胞的糖酵解和对多西他赛的耐药性，从而首次揭示了β-arrestin2调控CRPC多西他赛耐药的作用及分子机制，有助于充实前列腺癌化疗耐药的机制研究，并为临床增强前列腺癌多西他赛的敏感性，甚至逆转化疗耐药，提供新的实验依据和干预靶点。