High-Throughput Transcriptomic and RNAi Analysis Identifies AIM1, ERGIC1, TMED3 and TPX2 as Potential Drug Targets in Prostate Cancer

Prostate cancer is a heterogeneous group of diseases and there is a need for more efficient and targeted methods of treatment. In this study, the potential of gene expression data and RNA interference technique were combined to advance future personalized prostate cancer therapeutics. To distinguish the most promising in vivo prevalidated prostate cancer drug targets, a bioinformatic analysis was carried out using genome-wide gene expression data from 9873 human tissue samples. In total, 295 genes were selected for further functional studies in cultured prostate cancer cells due to their high mRNA expression in prostate, prostate cancer or in metastatic prostate cancer samples. Second, RNAi based cell viability assay was performed in VCaP and LNCaP prostate cancer cells. Based on the siRNA results, gene expression patterns in human tissues and novelty, endoplasmic reticulum function associated targets AIM1, ERGIC1 and TMED3, as well as mitosis regulating TPX2 were selected for further validation. AIM1, ERGIC1, and TPX2 were shown to be highly expressed especially in prostate cancer tissues, and high mRNA expression of ERGIC1 and TMED3 associated with AR and ERG oncogene expression. ERGIC1 silencing specifically regulated the proliferation of ERG oncogene positive prostate cancer cells and inhibited ERG mRNA expression in these cells, indicating that it is a potent drug target in ERG positive subgroup of prostate cancers. TPX2 expression associated with PSA failure and TPX2 silencing reduced PSA expression, indicating that TPX2 regulates androgen receptor mediated signaling. In conclusion, the combinatorial usage of microarray and RNAi techniques yielded in a large number of potential novel biomarkers and therapeutic targets, for future development of targeted and personalized approaches for prostate cancer management.

前列腺癌是一类异质性疾病群，亟需更为高效且靶向的治疗手段。本研究将基因表达数据（gene expression data）与RNA干扰（RNA interference）技术相结合，以推动未来前列腺癌个性化治疗的发展。为筛选出最具潜力的经体内预验证的前列腺癌药物靶点，研究团队利用9873例人体组织样本的全基因组（genome-wide）基因表达数据开展生物信息学分析（bioinformatic analysis）。最终筛选出295个基因，因其在前列腺组织、前列腺癌组织或转移性前列腺癌（metastatic prostate cancer）样本中呈现高mRNA表达（mRNA expression），将用于后续培养的前列腺癌细胞功能研究。其次，研究在VCaP与LNCaP前列腺癌细胞系中开展了基于RNA干扰的细胞活力检测（cell viability assay）。基于小干扰RNA（siRNA）实验结果、人体组织中的基因表达模式以及靶点新颖性，研究选取了与内质网（endoplasmic reticulum）功能相关的靶点AIM1、ERGIC1、TMED3，以及调控有丝分裂（mitosis）的TPX2进行后续验证。实验结果显示，AIM1、ERGIC1与TPX2尤其在前列腺癌组织中呈高表达；ERGIC1与TMED3的高mRNA表达与雄激素受体（androgen receptor，AR）及ERG癌基因的表达显著相关。ERGIC1基因沉默可特异性调控ERG癌基因阳性前列腺癌细胞的增殖，并抑制此类细胞中ERG的mRNA表达，表明其是ERG阳性前列腺癌亚组的强效药物靶点。TPX2的表达与前列腺特异性抗原（prostate-specific antigen，PSA）复发相关，且TPX2基因沉默可降低PSA的表达，提示TPX2可调控雄激素受体介导的信号通路。综上，本研究联合应用基因芯片（microarray）与RNA干扰技术，筛选得到大量潜在的新型生物标志物（biomarkers）与治疗靶点，为未来开发靶向性、个性化的前列腺癌管理方案提供了重要支撑。