Qiu Xiaonan, Pascal Laura E, Song Qiong, Zang Yachen, Ai Junkui, O'Malley Katherine J, Nelson Joel B, Wang Zhou
Tsinghua MD Program, School of Medicine, Tsinghua University, Beijing, China; Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
Neoplasia. 2017 Mar;19(3):207-215. doi: 10.1016/j.neo.2017.01.001. Epub 2017 Feb 3.
Elongation factor, RNA polymerase II, 2 (ELL2) is expressed and regulated by androgens in the prostate. ELL2 and ELL-associated factor 2 (EAF2) form a stable complex, and their orthologs in Caenorhabditis elegans appear to be functionally similar. In C. elegans, the EAF2 ortholog eaf-1 was reported to interact with the retinoblastoma (RB) pathway to control development and fertility in worms. Because RB loss is frequent in prostate cancer, ELL2 interaction with RB might be important for prostate homeostasis. The present study explored physical and functional interaction of ELL2 with RB in prostate cancer. ELL2 expression in human prostate cancer specimens was detected using quantitative polymerase chain reaction coupled with laser capture microdissection. Co-immunoprecipitation coupled with deletion mutagenesis was used to determine ELL2 association with RB. Functional interaction between ELL2 and RB was tested using siRNA knockdown, BrdU incorporation, Transwell, and/or invasion assays in LNCaP, C4-2, and 22Rv1 prostate cancer cells. ELL2 expression was downregulated in high-Gleason score prostate cancer specimens. ELL2 could be bound and stabilized by RB, and this interaction was mediated through the N-terminus of ELL2 and the C-terminus of RB. Concurrent siRNA knockdown of ELL2 and RB enhanced cell proliferation, migration, and invasion as compared to knockdown of ELL2 or RB alone in prostate cancer cells. ELL2 and RB can interact physically and functionally to suppress prostate cancer progression.
延伸因子，RNA聚合酶II，2（ELL2）在前列腺中由雄激素表达和调控。ELL2与ELL相关因子2（EAF2）形成稳定复合物，它们在秀丽隐杆线虫中的直系同源物似乎具有相似功能。在秀丽隐杆线虫中，据报道EAF2的直系同源物eaf-1与视网膜母细胞瘤（RB）通路相互作用，以控制线虫的发育和生育能力。由于RB缺失在前列腺癌中很常见，ELL2与RB的相互作用可能对前列腺内环境稳定很重要。本研究探讨了ELL2与RB在前列腺癌中的物理和功能相互作用。使用定量聚合酶链反应结合激光捕获显微切割技术检测人前列腺癌标本中的ELL2表达。采用免疫共沉淀结合缺失诱变技术确定ELL2与RB的关联。在LNCaP、C4-2和22Rv1前列腺癌细胞中，使用小干扰RNA（siRNA）敲低、溴脱氧尿苷掺入、Transwell和/或侵袭试验检测ELL2与RB之间的功能相互作用。在高Gleason评分的前列腺癌标本中，ELL2表达下调。ELL2可被RB结合并稳定，这种相互作用通过ELL2的N端和RB的C端介导。与单独敲低ELL2或RB相比，同时敲低ELL2和RB可增强前列腺癌细胞的增殖、迁移和侵袭。ELL2和RB可在物理和功能上相互作用，以抑制前列腺癌进展。
