Pei Nana, Jie Feilong, Luo Jie, Wan Renqiang, Zhang Yanling, Chen Xinglu, Liang Zhibing, Du Hongyan, Li Andrew, Chen Baihong, Zhang Yi, Sumners Colin, Li Jinlong, Gu Weiwang, Li Hongwei
School of Biotechnology, Southern Medical University, Guangzhou, Guangdong, China.
Department of Otolaryngology-Head and Neck Surgery, Guangdong No. 2 Provincial People's Hospital, Guangzhou, Guangdong, China.
PLoS One. 2014 Mar 21;9(3):e92253. doi: 10.1371/journal.pone.0092253. eCollection 2014.
Increased expression of angiotensin II type 2 receptor (AT2R) induces apoptosis in numerous tumor cell lines, with either Angiotensin II-dependent or Angiotensin II-independent regulation, but its molecular mechanism remains poorly understood. Here, we used PCR Array analysis to determine the gene and microRNA expression profiles in human prostate cancer cell lines transduced with AT2R recombinant adenovirus. Our results demonstrated that AT2R over expression leads to up-regulation of 6 apoptosis-related genes (TRAIL-R2, BAG3, BNIPI, HRK, Gadd45a, TP53BP2), 2 cytokine genes (IL6 and IL8) and 1 microRNA, and down-regulation of 1 apoptosis-related gene TNFSF10 and 2 cytokine genes (BMP6, BMP7) in transduced DU145 cells. HRK was identified as an up-regulated gene in AT2R-transduced PC-3 cells by real-time RT-PCR. Next, we utilized siRNAs to silence the up-regulated genes to further determine their roles on AT2R overexpression mediated apoptosis. The results showed downregulation of Gadd45a reduced the apoptotic effect by ∼30% in DU145 cells, downregulation of HRK reduced AT2R-mediated apoptosis by more than 50% in PC-3 cells, while downregulation of TRAIL-R2 enhanced AT2R-mediated apoptosis more than 4 times in DU145 cells. We also found that the effects on AT2R-mediated apoptosis caused by downregulation of Gadd45a, TRAIL-R2 and HRK were independent in activation of p38 MAPK, p44/42 MAPK and p53. Taken together, our results demonstrated that TRAIL-R2, Gadd45a and HRK may be novel target genes for further study of the mechanism of AT2R-mediated apoptosis in prostate cancer cells.
血管紧张素II 2型受体（AT2R）表达增加可诱导多种肿瘤细胞系凋亡，其调控方式既可以是血管紧张素II依赖型，也可以是血管紧张素II非依赖型，但其分子机制仍知之甚少。在此，我们使用PCR Array分析来确定用AT2R重组腺病毒转导的人前列腺癌细胞系中的基因和微小RNA表达谱。我们的结果表明，在转导的DU145细胞中，AT2R过表达导致6个凋亡相关基因（TRAIL-R2、BAG3、BNIPI、HRK、Gadd45a、TP53BP2）、2个细胞因子基因（IL6和IL8）和1个微小RNA上调，以及1个凋亡相关基因TNFSF10和2个细胞因子基因（BMP6、BMP7）下调。通过实时RT-PCR鉴定出HRK是AT2R转导的PC-3细胞中的上调基因。接下来，我们利用小干扰RNA使上调基因沉默，以进一步确定它们在AT2R过表达介导的凋亡中的作用。结果显示，在DU145细胞中下调Gadd45a可使凋亡效应降低约30%，在PC-3细胞中下调HRK可使AT2R介导的凋亡降低超过50%，而在DU145细胞中下调TRAIL-R2可使AT2R介导的凋亡增强超过4倍。我们还发现，下调Gadd45a、TRAIL-R2和HRK对AT2R介导的凋亡的影响在p38丝裂原活化蛋白激酶、p44/42丝裂原活化蛋白激酶和p53的激活方面是独立的。综上所述，我们的结果表明，TRAIL-R2、Gadd45a和HRK可能是进一步研究AT2R介导的前列腺癌细胞凋亡机制的新靶基因。
