ABSTRACT
The present study aimed to construct conditionally replicative adenovirus (CRAds) carrying small hairpin (sh)RNA targeting enhancer of zeste homolog 2 (EZH2), in order to study its effect on inhibiting prostate cancer (PCa) cell growth and invasion. Immunohistochemical analyses of EZH2 was performed in tumor tissue samples from PCa and benign prostate hyperplasia (BPH). The human telomerase reverse transcriptase (hTERT) promoter was chosen to transcriptionally control EZH2 gene expression to obtain adenoviral replication (AdhTERTEZH2shRNA) in human PCa cell lines. The inhibitory effect of AdhTERTEZH2shRNA on EZH2 expression was evaluated by reverse transcription-quantitative polymerase chain reaction and western blot analyses. Cell Counting Kit8 assays were used to examine the effects of the AdhTERTEZH2shRNA on cell proliferation. Transwell Matrigel invasion assays were used to detected cell invasion. Immunohistochemistry showed that EZH2 staining was stronger in castrationresistant prostate cancer (CRPC) samples, compared with androgendependent prostate cancer (ADPC) samples, and was absent in BPH. Furthermore, EZH2 expression knockdown suppressed PCa cell proliferation and invasion. In addition, it was found that AdhTERTEZH2shRNA selectively replicated and significantly reduced the expression of EZH2 in PCa cells lines. The growth ability and invasion of DU145 and PC3 cells in vitro was effectively inhibited by AdhTERTEZH2shRNA. Silencing the expression of EZH2 led to decreased expression of CCND1 and Ki67 and increased expression of Ecadherin, as determined by western blot analysis. Thus, it was shown that CRAds armed with EZH2 shRNA exhibited significant antitumor effects in human PCa cells. AdhTERTEZH2shRNA may be developed as a treatment for hormonerefractory PCa.
