Fu Xiaoqin, Ravindranath Lakshmi, Tran Nicholas, Petrovics Gyorgy, Srivastava Shiv
Department of Surgery, Center for Prostate Disease Research (CPDR), U.S. Military Cancer Institute, Uniformed Services University of the Health Sciences, Bethesda, MD 20852, USA.
DNA Cell Biol. 2006 Mar;25(3):135-41. doi: 10.1089/dna.2006.25.135.
PCGEM1 is a prostate tissue-specific, and prostate cancer-associated noncoding RNA (ncRNA) gene. Previous results revealed a significant association of elevated PCGEM1 expression levels in prostate cancer cells of African-American patients, whose mortality rate is the highest among prostate cancer patients. Functional study of PCGEM1 demonstrated a marked increase in colony formation in LNCaP prostate cancer cells and NIH3T3 mouse fibroblast cells. This study demonstrates that PCGEM1 overexpression in LNCaP cell culture model results in the inhibition of apoptosis induced by doxorubicin (DOX). Induction of p53 and p21(Waf1/Cip1) by DOX were delayed in LNCaP cells stably overexpressing PCGEM1 (LNCaP-PCGEM1 cells) compared to control LNCaP cells. The protein levels of cleaved caspase 7, and cleaved PARP were attenuated in DOXtreated LNCaP-PCGEM1 cells compared to control LNCaP cells. Similar results were observed in LNCaP cells transiently overexpressing PCGEM1. The inhibition of PARP cleavage by PCGEM1 overexpression was also observed in LNCaP-PCGEM1 cells incubated with etoposide and sodium selenite. Fluorescence-Activated Cell Sorter Annexin-V analysis revealed significantly lower percentage of apoptotic cells in DOX-treated LNCaP-PCGEM1 cells compared to control LNCaP cells. The attenuation of apoptic response appears to be androgen dependent in this experimental model, as androgen-independent variants of LNCaP cells did not exhibit this response. In summary, this study provides new insights into cell biologic functions and novel features of an ncRNA. Further, these data unravel biological mechanisms of cell growth/cell survival-associated functions of this ncRNA in a widely used prostate cancer cell culture model.
PCGEM1是一种前列腺组织特异性且与前列腺癌相关的非编码RNA（ncRNA）基因。先前的研究结果显示，非裔美国前列腺癌患者的癌细胞中PCGEM1表达水平升高，且该群体的死亡率在前列腺癌患者中是最高的。对PCGEM1的功能研究表明，LNCaP前列腺癌细胞和NIH3T3小鼠成纤维细胞的集落形成显著增加。本研究表明，在LNCaP细胞培养模型中过表达PCGEM1可抑制阿霉素（DOX）诱导的细胞凋亡。与对照LNCaP细胞相比，在稳定过表达PCGEM1的LNCaP细胞（LNCaP-PCGEM1细胞）中，DOX诱导的p53和p21（Waf1/Cip1）延迟出现。与对照LNCaP细胞相比，DOX处理的LNCaP-PCGEM1细胞中，裂解的半胱天冬酶7和裂解的PARP的蛋白水平减弱。在瞬时过表达PCGEM1的LNCaP细胞中也观察到了类似结果。在用依托泊苷和亚硒酸钠孵育的LNCaP-PCGEM1细胞中，也观察到PCGEM1过表达对PARP裂解的抑制作用。荧光激活细胞分选仪膜联蛋白-V分析显示，与对照LNCaP细胞相比，DOX处理的LNCaP-PCGEM1细胞中凋亡细胞的百分比显著降低。在该实验模型中，凋亡反应的减弱似乎依赖雄激素，因为LNCaP细胞的雄激素非依赖变体未表现出这种反应。总之，本研究为ncRNA的细胞生物学功能和新特性提供了新见解。此外，这些数据揭示了在广泛使用的前列腺癌细胞培养模型中，该ncRNA与细胞生长/细胞存活相关功能的生物学机制。
