Cyclosporin A inhibits phorbol ester-induced cellular proliferation and tumor promotion as well as phosphorylation of a 100-kd protein in mouse epidermis.
Mouse epidermis and HEL30 keratinocytes contain cellular binding sites for the immunosuppressive agent cyclosporin A (CsA). Phorbol ester-induced DNA synthesis and tumor promotion in mouse skin is strongly suppressed by CsA. The anti-tumor effect of CsA is not the consequence of destruction of initiated cells. CsA selectively inhibits the phosphorylation in vitro of a protein with the relative molecular mass of 100 kd in mouse epidermis and HEL30 cytosol. The CsA-suppressible phosphorylation in vitro does not depend on the addition of Ca2+, phospholipid and the phorbol ester TPA.
D000818:Animals; D002273:Carcinogens / Q000037:antagonists & inhibitors*; D002455:Cell Division / Q000187:drug effects*; D003524:Cyclosporins / Q000494:pharmacology*; D004247:DNA / Q000096:biosynthesis; D004817:Epidermis / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D008970:Molecular Weight; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D013755:Tetradecanoylphorbol Acetate / Q000037:antagonists & inhibitors*
D002273:Carcinogens; D003524:Cyclosporins; D010750:Phosphoproteins; D004247:DNA; D013755:Tetradecanoylphorbol Acetate