Prostate specific membrane antigen (PSMA): a novel modulator of p38 for proliferation, migration, and survival in prostate cancer cells.

BACKGROUND: Regulated activation of p38 is crucial for cell proliferation, survival, and metabolism. Our previous studies had showed that prostate specific membrane antigen (PSMA) can facilitate the proliferation, migration, survival of the LNCaP prostate cancer cell line, but the mechanisms are poorly defined.
METHODS: Our LNCaP cells had been stably transfected with lentivirus-mediated shRNA for PSMA silencing in previous study. We first testify the efficacy of PSMA knockdown in our LNCaP cell line. Then using this PSMA (-) LNCaP cell line, we compared the expression of PSMA and P-p38 by Western blotting among groups. Furthermore, we also performed immunofluorescence to confirm the change of P-p38 in cells. Then, cell viability and migration were measured by cell counting kit-8 reagent and Transwell analysis respectively. Flow cytometry was employed to evaluate cell survival.
RESULTS: After silencing the expression of PSMA, the level of the phospho-p38 (P-p38) decreased approximate 40% compared with the blank and NC groups (P < 0.05). When the cells were incubated with SB203582 (p38 inhibitor), the P-p38 in three groups was at low level and no difference among groups (P > 0.05). Then the results of immunofluorescence further proved the relationship between PSMA and P-p38. Decrease of cell viability, migration, and survival was observed upon PSMA silencing. SB203580, a specific inhibitor of p38 MAPK pathway, also reduced proliferation, migration, and survival of LNCaP cells.
CONCLUSION: These data suggests PSMA may stimulate prostate cancer cells proliferation, migration and survival through p38 MAPK pathway, revealing a novel mechanism for PSMA playing positive role on LNCaP cells.