Luo Y, Li M C, Zhao J H, Han Y L, Lin Y H, Wang Y X, Jiang Y G, Lu Q, Lan L
Department of Urology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China.
Zhonghua Yi Xue Za Zhi. 2018 Aug 28;98(32):2552-2558. doi: 10.3760/cma.j.issn.0376-2491.2018.32.004.
To investigate the role of hypoxia-inducible factor-1α (HIF-1α) and β-catenin in radioresistance of prostate cancer (PCa) cells. Two PCa cell lines, LNCaP and C4-2B, were grouped as: negative control (no treatment), HIF-1α overexpression group (transfected with HIF-1α plasmids), and β-catenin silencing group (transfected with HIF-1α plasmids and β-catenin-shRNA). Cell proliferation, cycle, invasion, and radiosensitivity were measured under normal or hypoxic condition. Radiosensitivity was tested in two mice PCa models (the LNCaP orthotopic BALB/c-nu mice model and the C4-2B subcutaneous SCID mice model). In both LNCaP and C4-2B cells, HIF-1α transfection led to an enhanced β-catenin nuclear translocation, while β-catenin silencing inhibited the β-catenin nuclear translocation. Enhanced β-catenin nuclear translocation caused by HIF-1α overexpression resulted in enhanced cell proliferation and invasion, altered cell cycle distribution, reduced apoptosis, and improved non-homologous-end-joining (NHEJ) repair under irradiation condition. In vivo imaging of orthotopic models showed that HIF-1α overexpression LNCaP cells produced tumors with 3-fold volume (=0.003 1) and 2-fold wet weight (=0.039 4) than those by negative control cells at day 21, and β-catenin silencing cells aberrantly reduced both tumor volume (=0.000 3) and wet weight (=0.017 5) than HIF-1α overexpression cells. In addition, C4-2B subcutaneous models showed similar tumor promotion effects induced by HIF-1α overexpression (tumor volume: =0.000 1 and wet weight: =0.047 3) and suppressive effects by β-catenin silencing (tumor volume: <0.000 1 and wet weight: =0.022 1) as LNCaP orthotopic xenograft with regard to tumor volume and wet weight. HIF-1α overexpression enhanced β-catenin nuclear translocation, which led to the activation of the β-catenin/NHEJ signaling pathway and increased cell proliferation, invasion, and DNA repair. These results suggest that HIF-1α overexpression led to radioresistance of PCa cells.
探讨缺氧诱导因子-1α（HIF-1α）和β-连环蛋白在前列腺癌细胞（PCa）放射抗性中的作用。将两种PCa细胞系LNCaP和C4-2B分为：阴性对照组（未处理）、HIF-1α过表达组（转染HIF-1α质粒）和β-连环蛋白沉默组（转染HIF-1α质粒和β-连环蛋白短发夹RNA）。在正常或缺氧条件下测量细胞增殖、周期、侵袭和放射敏感性。在两种小鼠PCa模型（LNCaP原位BALB/c-nu小鼠模型和C4-2B皮下SCID小鼠模型）中测试放射敏感性。在LNCaP和C4-2B细胞中，HIF-1α转染均导致β-连环蛋白核转位增强，而β-连环蛋白沉默则抑制β-连环蛋白核转位。HIF-1α过表达引起的β-连环蛋白核转位增强导致细胞增殖和侵袭增强、细胞周期分布改变、凋亡减少以及照射条件下非同源末端连接（NHEJ）修复改善。原位模型的体内成像显示，在第21天时，HIF-1α过表达的LNCaP细胞产生的肿瘤体积比阴性对照细胞大3倍（=0.003 1），湿重比阴性对照细胞大2倍（=0.039 4），而β-连环蛋白沉默细胞的肿瘤体积（=0.000 3）和湿重（=0.017 5）均比HIF-1α过表达细胞异常减少。此外，C4-2B皮下模型显示，与LNCaP原位异种移植相比，HIF-1α过表达诱导的肿瘤促进作用（肿瘤体积：=0.000 1，湿重：=0.047 3）和β-连环蛋白沉默的抑制作用（肿瘤体积：<0.000 1，湿重：=0.022 1）在肿瘤体积和湿重方面相似。HIF-1α过表达增强了β-连环蛋白核转位，导致β-连环蛋白/NHEJ信号通路激活，细胞增殖、侵袭和DNA修复增加。这些结果表明，HIF-1α过表达导致PCa细胞产生放射抗性。
