Overexpression of EIF3S3 promotes cancer cell growth

BACKGROUND Amplification and overexpression of EIF3S3 gene has been demonstrated in breast and prostate cancer. Here, our goal was to study the effect of EIF3S3 on cell growth. METHODS The effect of EIF3S3 on growth of NIH 3T3 murine fibroblasts as well as breast (SK‐Br‐3 and ZR‐75‐1) and prostate (PC‐3 and LNCaP) cancer cell lines was examined by using transfection with inducible pTet‐Off system and siRNAs. RESULTS NIH 3T3 cells with overexpression of EIF3S3 grew significantly faster than cells transfected with empty vector and survived longer when grown in soft agar. The EIF3S3 overexpression was associated with increased fraction of cells in S‐phase and with phosphorylation of retinoblastoma (Rb) protein. siRNA treatment inhibited significantly (P = 0.0022) the growth of all breast and prostate cancer cell lines studied. CONCLUSIONS The results suggest that EIF3S3 regulates cell growth and viability, and that overexpression of the gene may provide growth advantage to the cancer cells. Prostate © 2006 Wiley‐Liss, Inc.