CK2催化亚单位调控AR促进前列腺癌激素抵抗性进展机制研究

Prostate cancer is the most common cancer and the second leading cause of cancer death in men in US. Almost all prostate cancer patients treated with androgen ablation therapy relapse as more aggressive tumors termed now as castration-resistant prostate cancer(CRPC). Although it has a tremendous impact on public health, CRPC is not curable and optimization of the conventional androgen ablation is currently under investigation. CK2 expression and activity are elevated in a wide variety of human cancers, especially in prostate cancers. However, it is not fully clear how CK2 inhibition affects androgen receptor (AR)-mediated gene expression and which catalytic subunits of the CK2 complex are involved in AR signaling.Our previous in vitro studies indicated that CK2 inhibition attenuated AR-mediated gene expression and cell proliferation in prostate cancer cells, and caused a G2/M phase arrest. Furthermore, out data revealed that CK2 activity is required for androgen-stimulated AR nuclear localization. In this study,the expression of the catalytic subunit of CK2 in different prostate tissue was detected by immunohistochemistry, Western blot analysis and real-time quantitative PCR.The catalytic subunit of CK2 were used to intervene the heterogeneous tumor-bearing model in Vivo,while molecular biology techniques was performed to investigate the effects and mechanism of catalytic subunit of CK2 on AR in Human CRPCa Cells. This study aims to explore: (1) differential expression of catalytic subunit of CK2 in different prostate tissue,which will provide theoretical basis for clinical practice; (2)in Vivo the catalytic subunit of CK2 on the effect of aggressive CRPCa Cells; (3)different effects of catalytic subunit of CK2 on AR in Human CRPCa Cells, which will guide choose on therapeutic targets of CK2 complex specifically.

前列腺癌是威胁人类健康重要疾病，去势抵抗性前列腺癌（CRPC）现有的治疗方案欠佳。CK2表达和活性在多种人类肿瘤中上升，特别是前列腺癌，但关于CK2抑制剂能否有效抑制CRPC细胞系及其不同催化亚单位调控雄激素受体（AR）促进前列腺激素抵抗机制尚不清楚。我们的前期体外研究首次证实CK2抑制剂减弱AR介导的基因表达和细胞增殖，引起细胞周期停滞，同时减弱雄激素刺激的AR核定位。本项目拟检测人体不同前列腺组织中CK2催化亚单位表达，体内实验观察CK2抑制剂对CRCP异种荷瘤模型效应，并探讨CK2催化亚单位是否都参与了雄激素刺激的AR反式激活及调控AR核定位机制。本课题旨在阐明：（1）人体不同前列腺组织中CK2催化亚单位表达差异，为临床治疗提供理论依据；（2）CK2抑制剂对CRPC细胞系体内效应；（3）CK2催化亚单位调控AR核定位机制，为设计AR信号肽通路特异性CK2抑制剂提供了重要信息。

蛋白激酶2（CK2）是一种具有广泛底物的高度保守性激酶。已有很多研究表明CK2参与多种肿瘤发生发展的相关进程，如细胞周期、细胞凋亡以及侵袭转移等。目前已有多种CK2的靶向抑制剂被开发出来。其中CX4945是新近开发的，特异性最高的CK2抑制剂。目前CX4945已经在开展I期及II期临床试验（NCT02128282）。有研究报道CK2的异常激活与前列腺癌的发生发展密切相关，而且与较差预后相关。我们前期研究也表明抑制CK2活性，可以降低雄激素受体（AR）的转录活性，从而抑制激素依赖性前列腺癌细胞的生长增殖。然而，CK2抑制剂是否同样可以抑制依赖雄激素剪切变异体（AR-Vs）的激素抵抗性前列腺癌（CRPC）细胞的生长增殖仍需进一步探讨。.本研究首次探讨了CK2抑制剂CX4945可以抑制CRPC细胞系22Rv1和VCaP在体外的增殖。22Rv1和VCaP细胞系是理想而且常用的研究CRPC的细胞模型，这两个细胞都表达AR-V7。CX4945可以引起22Rv1细胞的周期阻滞，同时也可以引起细胞凋亡。与此前在AR依赖细胞系中观察到的不同，CX4945并不影响AR-FL的表达。相反的，它可以显著抑制AR-V7的转录以及翻译。同时发现CX4945可以降低细胞核中的AR-V7水平，从而抑制AR-V7对靶基因的调控。qPCR以及ELISA检测结果都显示，CX4945可以显著降低细胞表达以及分泌的PSA水平。这也验证了CX4945可以抑制CRPC细胞系中AR-V7的转录功能。CRPC细胞系对于传统的抗AR治疗，如比卡鲁胺，并不敏感。但在与CX4945合用的情况下却可以显著地抑制CRPC细胞的生长。.已有研究表明CK2可以磷酸化NF-kB p65的ser529位点，从而激活NF-kB通路。而NF-kB通路的激活又与CRPC的发生密切相关。因此，我们推测CK2抑制剂CX4945是通过抑制NF-kB通路的活性，从而来抑制AR-V7的表达。Western blot实验结果显示，CX4945可以减少p65在ser529位点的磷酸化，以及p50和p65的核转位，这表明CX4945可以抑制NF-kB通路的激活。此外，应用NF-kB的抑制剂QNZ也可以显著抑制AR-V7的表达，并且抑制CRPC细胞的体外增殖。.以上研究结果为CRPC的治疗提供了一个新的治疗靶点。