Abstract: Objective To investigate the role of selenocysteine-tRNA specific eukaryotic elongation factor (EEFSEC) in regulating the proliferation, migration, and invasion of human prostate cancer 22Rv1 cells. Methods We detected EEFSEC mRNA expression levels in human normal prostate cell line RWPE1 and human prostate cancer cell lines 22Rv1, LNCaP, Vcap and PC-3 using qRT-PCR and EEFSEC protein expression in surgical specimens of prostate cancer and adjacent tissues using Western blotting. 22Rv1 cells were infected with a lentiviral vector carrying EEFSEC shRNA or a control lentivirus and the interference efficiency was determined using Western blotting. XTT assay was used to assess the changes in the viability of the infected cells, and Transwell chamber assay was used to examine the changes in cell migration and invasion. The effect of EEFSEC knockdown on cell cycle progression was determined with flow cytometry and by detecting the expressions of cell cycle proteins using qRT-PCR. Results EEFSEC was significantly upregulated in prostate cancer cells (P<0.05), and a high expression of EEFSEC was associated with a poor prognosis of the patients with prostate cancer. In 22Rv1 cells, EEFSEC knockdown significantly suppressed the proliferation (P<0.001), migration (P<0.001) and invasion (P<0.001) of the cells, resulted in cell cycle arrest in G0/G1 phase, obviously inhibited the expression of C-myc and CCNB1, and significantly increased the expression of p15. Conclusion EEFSEC knockdown can inhibit the proliferation, migration, and invasion of prostate cancer cells in vitro possibly by down-regulating the expression of C-myc.

Key words: prostate cancer; EEFSEC; proliferation; migration; invasion