PSCA promotes prostate cancer proliferation and cell-cycle progression by up-regulating c-Myc.

BACKGROUND: The Prostate stem cell antigen (PSCA) is a glycosylphosphatidylinositol (GPI)-anchored protein. Increasing evidence has indicated PSCA plays an important role in tumorigenesis. However, its function and the underlying molecular mechanisms in prostate cancer (PCa) are still not fully elucidated. In this study, we aimed to explore the effect of PSCA on cell cycle of PCa cells and its mechanism research.

METHODS: Immunohistochemistry, quantitative reverse transcription-PCR (qRT-PCR) and Western blotting were used to quantify PSCA expression pattern in PCa tissues and cell lines. The association of PSCA expression with the biochemical recurrence (BCR)-free survival and overall survival (OS) of PCa patients were analyzed using Kaplan-Meier method. The roles of PSCA in PCa were confirmed based on both in vitro and in vivo systems.

RESULTS: Immunohistochemistry results showed that PSCA was upregulated in PCa tissue. PSCA overexpression were significantly associated with high Gleason score (GS) (P = 0.028), positive BCR (P = 0.002), and poor OS (P = 0.032) and high c-Myc expression (P = 0.019). PSCA promoted PCa cell cycle progression and tumor growth via increased c-Myc expression. Additional, PI3K/AKT signaling pathways was involved in PSCA-mediated c-Myc expression and cell proliferation.

CONCLUSIONS: PSCA is a novel cell cycle regulator with a key role in mediating c-Myc-induced proliferation. PSCA may be a potential diagnostic marker and therapeutic target for patients with PCa.