Effect of phorbol esters on the susceptibility of a glioma cell line to lymphokine-activated killer cell activity.
The mechanisms by which lymphokine-activated killer (LAK) cells exert their cytotoxic effects are not well understood. This study demonstrates that phorbol ester pretreatment of a LAK cell-sensitive glioma cell line (SNB-19) induced a significant decrease in the susceptibility of cells to LAK cell-mediated lysis. This effect was produced by low concentrations of the tumor-promoting phorbol ester, phorbol-12,13-myristate acetate (PMA), and was reversible. Protein kinase C (PKC) inhibitors failed to block this phenomenon. No apparent alteration in the ability of LAK cells to bind to their targets was observed. Thus, PMA may have exerted its effects by a mechanism that does not require PKC, or these glioma cells may possess an isozyme of PKC which is insensitive to the inhibitors used in these studies.
Maleci
A
A
Department of Neurosurgery, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, New York.
Alterman
R L
RL
Sundstrom
D
D
Kornblith
P L
PL
Moskal
J R
JR
D002455:Cell Division / Q000187:drug effects; D005910:Glioma / Q000276:immunology* / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D015979:Killer Cells, Lymphokine-Activated / Q000187:drug effects*; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology; D010703:Phorbol Esters / Q000494:pharmacology*; D010704:Phorbols / Q000494:pharmacology; D011493:Protein Kinase C / Q000502:physiology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013936:Thymidine / Q000378:metabolism; D014407:Tumor Cells, Cultured
D010703:Phorbol Esters; D010704:Phorbols; D015240:Phorbol 12,13-Dibutyrate; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate; D013936:Thymidine; C033085:phorbol