Tumor-promoting phorbol esters stimulate the proliferation of interleukin-3 dependent cells

✍ Scribed by Beth B. Hogans; Dr. Jerry L. Spivak

• Publisher: John Wiley and Sons
• Year: 1988
• Tongue: English
• Weight: 721 KB
• Volume: 137
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/jcp.1041370219

✦ Synopsis

To determine whether activation of protein kinase C is involved in the proliferation of interleukin-3 (IL-3) -dependent cells, we examined the effect of tumor-promoting phorbol esters on the in vitro proliferation of the IL-3dependent cell lines FD and DA-1. The viability of FD and DA-1 cells cultured for 24 hours in 100 nM phorbol myristate acetate (PMA) and 10% FCS was similar to that of cells cultured in 25% WEHI-3 conditioned medium as a source of IL-3, and 10% FCS. FD cells failed to proliferate in concentrations of FCS of u p to 50%, while DA-1 cell proliferation was not markedly influenced by FCS. By contrast, PMA promoted the proliferation of FD and DA-I cells in the absence of FCS and enhanced their proliferation in the presence of 10% FCS, 60-and 20-fold, respectively. Stimulation of proliferation was achieved with as little as 10 nM PMA and was maximal at 100 nM PMA. Low concentrations (0.05-0.1%) of WEHI-3 CM promoted t h e proliferative response of FD and DA-1 cells to PMA, but at concentrations of WEHI-3 CM greater than 0.8%, n o further increment in proliferation was obtained with PMA. As little as 112 hour of exposure to phorbol esters was sufficient to cause translocation of protein kinase C from the cytosol to the membranes of DA-1 cells, and 1 hour of exposure to phorbol esters was sufficient to stimulate DNA synthesis. A protein kinase C inhibitor, H-7, at a concentration of 10 pM inhibited phorbol ester-induced stimulation of DA-1 cell proliferation. When DA-1 cells were exposed to the calcium ionophore A23187 in addition to both a phorbol ester and IL-3, their proliferation was enhanced over that stimulated by only the phorbol ester and 1L-3. The data indicate that stimulation of proliferation of IL-3-dependent cells involves the activation of protein kinase C.