Tumor Induced Suppression of NFkB Activation in T Cells Derived from Patients with Renal Cell Carcinoma; The Role of Prostaglandin E2

Kim, Hyung Jin; Park, Jong Kwan; Kim, Young Gon; Park, Young Kyung

Abstract

PURPOSE: T lymphocytes from patients with renal cell carcinoma(RCC) show reduced immune function and impaired activation of the transcription factor, NFkB. Recent work from this laboratory shows that supernatant fluid from RCC explants can inhibit activation of NFkB. Because PGE2 can suppress T cell function and is present in supernatant fluid from RCC explants, we determined if PGE2 could suppress the activation of NFkB.
MATERIALS AND METHODS
Peripheral blood T cells from normal volunteers and RCC patients were stimulated with crosslinked antiCD3 antibody and IL-2(1000u/ml) or PMA(20ng/m1) and lonomycin(0.75rg/m1) for various lengths of time. The effect that PGE, and RCC-5(supernatant fluid from RCC) had on NFkB was assessed by adding PGE2 or RCC-S to normal T cells using western blotting and electrophoretic mobility shift assay(EMSA).
RESULTS
T cell activation results in the nuclear expression of two KB binding complexes(C 1 and C2) as determined by EMSA. However, PGE2 suppressed the nuclear expression of KB binding activity with 10-5M PGE2 having the most effect. PGE2 and RCC-S suppressed the expression of Cl which is composed of NFkB1, ReIA and c-Rel whereas it had minimal erect on C2 which is composed only of NFkB1. Western blotting verified that PGE2 and RCC-S significantly reduced the nuclear but not the cytoplasmic levels of ReIA, NFkBl and c-Rel. Furthermore, the results obtained with PGE2 and RCC-S are similar to those obtained with T cells from RCC patients
CONCLUSIONS
These results demonstrate that PGE2 can suppress NFkB activation in T cells through inhibiting the nuclear translocation of ReIA, NFkBl and c-Rel. PGE2 may contribute to the inhibition of NFkB that is mediated by RCC supernatant.