Lymphocytes can be stimulated to proliferate in vitro by mitogens such as concanavalin A. The tumor-promoting Phorbol ester 12-O-tetradecanoyl Phorbol-13-acetate(TPA)can enhance this proliferation, partly because of an increase in interleukin 2 (IL-2) production. However, if lymphocytes are treated with TPA for 24 h before concanavalin A exposure, IL-2 production and proliferation are depressed. The target of the action of TPA is protein kinase C, which is activated after a short exposure but down-regulated after a longer one. This study was designed to determine if the modulation of IL-2 was separable from the modulation of protein kinase C. \\hen Phorbol esters Phorbol 12-retinoate-13-acetate, Phorbol 12,13-dibutyrate, 12-deoxyPhorbol 13-phenylacetate, and 12-deoxyPhorbol 13-phenylacetate-20-acetate, as well as nonPhorbol tu mor promoters mezerein, telocidin, and okadaic acid, were tested, all but okadaic acid reproduced the effects of TPA. However, 12-deoxyPhorbol 13-phenylacetate and 12-dcoxyPhorbol 13-phenylacetate-20-acetate were required at nearly 100-fold higher concentrations than TPA to suppress IL-2 production, suppress mitogenesis, and cause down-regulation of protein kinase C. A comparison of structures indicated that an R group at the 12-position was less important for IL-2 production and mitogenesis than for down-regulation of protein kinase C and the suppression of mitogenesis. In no case was the modulation of protein kinase C separated from the effects on IL-2 production and proliferation.
|Original language||English (US)|
|Number of pages||7|
|State||Published - Jan 1991|
All Science Journal Classification (ASJC) codes
- Cancer Research