TY - JOUR
T1 - Mitogenic conversion of transforming growth factor-β1 effect by oncogenic Ha-Ras-induced activation of the mitogen-activated protein kinase signaling pathway in human prostate cancer
AU - Park, Bum Joon
AU - Park, Jae Il
AU - Byun, Do Sun
AU - Park, Jae Hoon
AU - Chi, Sung Gil
N1 - Copyright:
Copyright 2007 Elsevier B.V., All rights reserved.
PY - 2000/6/1
Y1 - 2000/6/1
N2 - Elevated expression of transforming growth factor (TGF)-β1 has been implicated in prostate tumorigenesis despite its growth-inhibitory effect on normal epithelial and carcinoma cells of the prostate. In this study, we identified that G1-to-S transition of the cell cycle is stimulated by TGF- β1 in the prostate cancer cell line TSU-Pr1. No mutation of signal mediators, including Smads, and induction of PAI-1 transcription indicated that the TGF-β1 signaling cascade is functionally intact in this cell line. Whereas pharmacological inhibitors of various mitogenic signaling pathways showed no effects, blockade of the mitogen-activated protein kinase (MAPK) pathway by the MAPK kinase 1 inhibitor PD98059 restored the growth inhibitory role of TGF-β1 in TSU-Pr1, which carries an oncogenic mutation in Ha-Ras (V12). Moreover, expression of antisense Ha-Ras or dominant negative Raf-1 abrogated the mitogenic effect of TGF-β1 in TSU-Pr1, and the TGF-β1 inhibition of DU145 was switched to stimulation by V12Ha-Ras transfection. Whereas the negative growth regulation by TGF-β1 was completely inhibited by dominant negative Smad2, Smad3, or Smad4, its mitogenic effect was not affected, suggesting that this action is Smad-independent. Interestingly, whereas the TGF-β1-mediated up-regulation of p15(INK4B) and p21(WAF1) transcription was abolished in TSU-Pr1 and V12Ha-Ras-transfected DU145, inhibition of the Ras/MAPK pathway restored the TGF-β1 induction of these genes. Taken together, our data suggest that prostate carcinomas with the Ras/MAPK pathway activation might have a selective growth advantage by autocrine TGF-β1 production.
AB - Elevated expression of transforming growth factor (TGF)-β1 has been implicated in prostate tumorigenesis despite its growth-inhibitory effect on normal epithelial and carcinoma cells of the prostate. In this study, we identified that G1-to-S transition of the cell cycle is stimulated by TGF- β1 in the prostate cancer cell line TSU-Pr1. No mutation of signal mediators, including Smads, and induction of PAI-1 transcription indicated that the TGF-β1 signaling cascade is functionally intact in this cell line. Whereas pharmacological inhibitors of various mitogenic signaling pathways showed no effects, blockade of the mitogen-activated protein kinase (MAPK) pathway by the MAPK kinase 1 inhibitor PD98059 restored the growth inhibitory role of TGF-β1 in TSU-Pr1, which carries an oncogenic mutation in Ha-Ras (V12). Moreover, expression of antisense Ha-Ras or dominant negative Raf-1 abrogated the mitogenic effect of TGF-β1 in TSU-Pr1, and the TGF-β1 inhibition of DU145 was switched to stimulation by V12Ha-Ras transfection. Whereas the negative growth regulation by TGF-β1 was completely inhibited by dominant negative Smad2, Smad3, or Smad4, its mitogenic effect was not affected, suggesting that this action is Smad-independent. Interestingly, whereas the TGF-β1-mediated up-regulation of p15(INK4B) and p21(WAF1) transcription was abolished in TSU-Pr1 and V12Ha-Ras-transfected DU145, inhibition of the Ras/MAPK pathway restored the TGF-β1 induction of these genes. Taken together, our data suggest that prostate carcinomas with the Ras/MAPK pathway activation might have a selective growth advantage by autocrine TGF-β1 production.
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M3 - Article
C2 - 10850453
AN - SCOPUS:0034214211
SN - 0008-5472
VL - 60
SP - 3031
EP - 3038
JO - Cancer Research
JF - Cancer Research
IS - 11
ER -