title: Suppression of apoptosis in COLO 205 cells by the phorbol ester TPA may be mediated by the PKC isoenzyme alpha.
abstract: Apoptosis induced by an antibody to CD95/APO-1/FAS in the colon carcinoma cells COLO 205 and HT-29 is suppressed by the phorbol ester TPA. Inhibition is much more effective in COLO 205 than in HT-29 cells. The TPA effect is abrogated by the protein kinase C (PKC)-specific inhibitor Go6983 indicating a role of PKC in this process. Bryostatin 1, unlike TPA, is unable to suppress apoptosis, but inhibits the TPA-induced suppression of apoptosis. TPA also inhibits indomethacin-induced apoptosis in COLO 205 cells. COLO 205 and HT-29 cells contain the PKC isoenzymes alpha, beta(II) delta, epsilon, eta, mu and zeta. Expression and activity of PKC alpha are at least 5 times higher in COLO 205 than in HT-29 cells. This correlates with the fact that inhibition of CD95-mediated apoptosis by TPA is more prominent in COLO 205 than in HT-29 cells. Thus, these findings suggest that PKC alpha has an important role in the TPA-induced inhibition of apoptosis.
authors.affiliation: GERMAN CANC RES CTR,DIV BIOCHEM TISSUE SPECIF REGULAT,D-69120 HEIDELBERG,GERMANY. GERMAN CANC RES CTR,DIV IMMUNOGENET,D-69120 HEIDELBERG,GERMANY. UNIV ULM,INST PATHOL,D-89081 ULM,GERMANY.
authors.forename: E
authors.initials: E
authors.lastname: Weiss
authors.forename: U
authors.initials: U
authors.lastname: Vonreyher
authors.forename: W
authors.initials: W
authors.lastname: Kittstein
authors.forename: P
authors.initials: P
authors.lastname: Moller
authors.forename: P
authors.initials: P
authors.lastname: Krammer
authors.forename: F
authors.initials: F
authors.lastname: Marks
authors.forename: M
authors.initials: M
authors.lastname: Gschwendt