Effects of wortmannin and rapamycin on CSF-1-mediated responses in macrophages

Abstract

There are differing views regarding the roles of phosphatidylinositol 3- kinases (PI3-kinases) and p70 S6 kinase (p76(s6k)) in growth factor-induced cellular responses. One approach that is widely employed to investigate these roles is to use the inhibitors, wortmannin and rapamycin, respectively. This approach is used here to study the responses in macrophages to colony stimulating factor-1 (CSF-1). Wortmannin (≤30 nM) and rapamycin (≤3 nM) both weakly inhibited CSF-1-stimulated DNA synthesis in murine bone marrow- derived macrophages (BMM), suggesting that there are PI3-kinase- and p70(s6k)-independent pathways required for the onset of the S phase; interestingly the combination of the dru..