TRANSFORMING GROWTH FACTOR ß2 UP-REGULATES GM-CSF GENE IN HUMAN BLADDER CARCINOMA CELL LINE HTB 5637

Abstract

Transforming growth factor betas are multifunctional polypeptides in the cytokine superfamily. They have a growth inhibitory role on hemopoietic pro­ genitor cells in semisolid colony assay as well as in long-term bone-marrow cul­ ture. TGF -�2 represses stromal cells, stem cell factor gene transcription, and de­ creases the stability of c-kit transcripts in hemopoietic cells. TGF-� also modu­ lates GM-CSF production from human lymphocytes. The present study reveals the TGF-�2 role in production of GM-CSF in HTB 5637, human bladder carci­ noma cell line. HTB 5637 cells were treated with 5 ng/mL of human TGF -�?' viable cells were counted and GM-CSF concentration was determined, No anti­ proliferate activity of TGF-�2 on HTB 5637 cell line was observed. Biological assay showed increased levels of GM-CSF in the supernatant of cultured cells. However this increase was lower than that expected from ELISA. Since TGF-� may be an active suppressor factor regulating hemopoiesis, it seems that some inhibitory factor(s) may be produced (increased) in response to TGF-�2 treat­ ment. It has been shown that GM-CSF mRNA content from HTB 5637 cell line is very stable and this stabilization is translational dependent. Using Slot blot and Northern blot analysis, we determined that TGF-�2 upregulated GM-CSF gene expression in HTB 5637 cell line. The results suggest that TGF-�2 upregulates the production of GM-CSF gene at the transcriptional level. MJIRl, Vol. 15, No.4, 219-225, 2002.