WILD-TYPE P53-INDUCED APOPTOSIS IN A BURKITT-LYMPHOMA CELL-LINE IS INHIBITED BY INTERFERON-GAMMA

The tumor suppressor p53 plays a central role in negative growth contr ol, including growth arrest and apoptosis. Interferons (IFNs) are capa ble of modulating a variety of cellular responses, including apoptosis . In this study, we have evaluated the influence of gamma- and alpha-i nterferon (IFN) on wild-type (wt) p53-induced apoptosis using a Burkit t lymphoma cell line, BL41, transfected with a temperature-sensitive p 53 construct. gamma-IFN, but not alpha-IFN, was found to protect cells from wt p53-induced apoptosis. The gamma-IFN-dependent protection was due neither to down-regulation of p53, nor to the p53-induced genes, p21 (WAF-I) and box, nor to up-regulation of bcl-2 or bcl-x(L). Expres sion of the proto-oncogene c-myc, implicated in the control of both pr oliferation and apoptosis, was not affected by gamma-IFN. We conclude that gamma-IFN can suppress p53-induced apoptosis, and that the cytoki ne microenvironment may be decisive in the cellular response to wt p53 expression. (C) 1996 Wiley-Liss, Inc.