[PubMed] [Google Scholar] 37

[PubMed] [Google Scholar] 37. and protein expression levels as well as FosB subcellular localization. Transient silencing of FosB protein was used to determine its role in cell proliferation, migration, and invasion. RESULTS Our data show that FOS mRNA and proteins were differentially expressed in human prostate epithelial (RWPE-1) and prostate cancer cell lines (LNCaP, DU145, and PC3). TGF-1 induced the expression of FosB at both the mRNA and protein levels in DU145 and PC3 cells, whereas cFos and Fra1 were unaffected. Immunofluorescence analysis showed an increase in the accumulation of FosB protein in the nucleus of PC3 cells after treatment with exogenous TGF-1. Selective knockdown of endogenous FosB by specific siRNA did not have any effect on cell proliferation in PC3 and DU145 cells. However, basal and TGF-1- and EGF-induced cell migration was significantly reduced in DU145 and PC3 NKY 80 cells lacking endogenous FosB. TGF-1- and EGF-induced cell invasion were also significantly decreased after FosB knockdown in Parp8 PC3 cells. CONCLUSION Our data suggest that FosB is required for migration and invasion in prostate cancer cells. We also conclude that TGF-1 effect on prostate cancer cell migration and invasion may be mediated through the induction of FosB. < 0.05) from untreated controls. (D) The Dose dependent effects of TGF-1 on expression of FosB; Western blot analysis of FosB in prostate cancer cells DU145 and PC3 after treatment with varying concentrations of exogenous TGF-1 (0, 1, 5, 10 ng/ml) for 4 hr. (E) Immunofluorescence, TGF-1 activation of FosB in PC3. Cells were treated with exogenous TGF-1 (10 ng/ml) for 0 and 4 hr. FosB Knockdown Has No Effect on TGF-1-Mediated Cell Proliferation But Abrogates TGF-1 and EGF-Mediated Cell Migration and Invasion Next, we determined the role of FosB in TGF-1-induced cell proliferation, migration and invasion in prostate cancer cells. A transient knock down of FosB was carried out using siRNA specific to FosB, followed by a MTT proliferation (Fig. 3A and B), trans-well inserts migration assays (Fig. 4A and B), NKY 80 and matrigel invasion assays (Fig. 5). Knock down of FosB had no effect on cell proliferation in DU145 and PC3 cells (Fig. 3A and B); however, there was a significant decrease in cell migration (DU145, PC3) and cell invasion (PC3) in response to TGF-1 and EGF in these cells (Fig. 4A, B and Fig. 5). Our data also suggests that FosB knockdown reduced both TGF-1- and EGF-induced cell invasion but had no significant effect on the basal invasive potential of these cells (Fig. 5). Open in a separate window Fig. 3 Effects of FosB knock down on TGF-1-induced cell proliferation. DU145 (A) and PC3 (B) cells were transfected with siRNA to transiently silence FosB followed by an in vitro proliferation assay. Open in a separate window Fig. 4 Effects of FosB knock down on cell migration. Prostate cancer cells DU145 (A) and PC3 (B) were pretreated with siRNA against FosB for 72 hr. Western blots were used to confirm knock down of endogenous FosB (inserts). DU145 and PC3 cells were pretreated with siRNA against FosB, followed by treatment with 10 ng/ml of exogenous TGF-1 and 10 ng/ml EGF migratory behavior were measured using transwell insert migration assay. Each bar represents Mean SEM from three independent experiments. Different letters designate statistically significant (< 0.05) differences among different treatments. Open in a separate window Fig. 5 Effects of FosB knock down on cell invasion. PC3 cells were pretreated with siRNA against FosB, followed by treatment with 10 ng/ml of exogenous TGF-1 and 10 ng/ml EGF. Invasive behavior was measured using a matrigel in vitro invasion assay. Insert shows western blot used to confirm FosB knock down. Each bar represents Mean SEM from three independent experiments. Different letters designate statistically significant (< 0.05) differences among different treatments. DISCUSSION In this study, we demonstrate for the first time the role of Fos transcription factors NKY 80 in migration.