Effects of wortmannin and rapamycin on CSF-1-mediated responses in macrophages.
There are differing views regarding the roles of phosphatidylinositol 3-kinases (PI3-kinases) and p70 S6 kinase (p70s6k) 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 (> or = 30 nM) and rapamycin (> or = 3 nM) both weakly inhibited CSF-1-stimulated DNA synthesis in murine bone marrow-derived macrophages (BMM), suggesting that there are PI3-kinase- and p70s6k-independent pathways required for the onset of S phase; interestingly the combination of the drugs gave dramatic suppression. Inhibition of DNA synthesis by rapamycin on the BMM was much less than that observed with the CSF-1-dependent cell line, BAC1.2F5. In BMM, wortmannin suppressed CSF-1-stimulated increase in p70s6k activity indicating that PI3-kinase activity may lie upstream. In contrast to some other growth factor/cell systems, no evidence was obtained using the inhibitors for the involvement of PI3-kinase or p70s6k in CSF-1-mediated induction of c-fos mRNA expression or Erk-1 activity; in addition, no evidence was found for an involvement in the CSF-1-mediated increase in cyclin D1 expression or STAT activation. The findings reinforce the need to study the signal transduction cascades relevant to each individual growth factor and preferably not in cell lines.
Hamilton
J A
JA
Inflammation Research Centre, University of Melbourne, Department of Medicine, Royal Melbourne Hospital, Parkville, Vic., Australia. j.hamilton@medicine.unimelb.edu.au
Byrne
R
R
Whitty
G
G
Vadiveloo
P K
PK
Marmy
N
N
Pearson
R B
RB
Christy
E
E
Jaworowski
A
A
D000730:Androstadienes / Q000494:pharmacology*; D000818:Animals; D001854:Bone Marrow Cells / Q000187:drug effects; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics; D002460:Cell Line; D019938:Cyclin D1 / Q000096:biosynthesis; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology*; D004247:DNA / Q000096:biosynthesis; D004790:Enzyme Induction / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D016762:Genes, fos / Q000235:genetics; D016173:Macrophage Colony-Stimulating Factor / Q000494:pharmacology*; D008264:Macrophages / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D019869:Phosphatidylinositol 3-Kinases / Q000096:biosynthesis; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011090:Polyenes / Q000494:pharmacology*; D012333:RNA, Messenger / Q000096:biosynthesis; D019893:Ribosomal Protein S6 Kinases / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D020123:Sirolimus; D000077191:Wortmannin
D000730:Androstadienes; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D019938:Cyclin D1; D015853:Cysteine Proteinase Inhibitors; D004247:DNA; D004791:Enzyme Inhibitors; D016173:Macrophage Colony-Stimulating Factor; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011090:Polyenes; D012333:RNA, Messenger; D019893:Ribosomal Protein S6 Kinases; D020123:Sirolimus; D000077191:Wortmannin