MECHANISM &REGULATION OF BCL-2 ANTIPROLIFERATIVE EFFECT

Northwestern University, Evanston IL

Investigators

Linked publications & trials

Abstract

DESCRIPTION: (adapted from the investigator's abstract) Programmed cell death, or apoptosis, is an active form of cellular suicide that functions physiologically to ensure that superfluous or unwanted cells are eliminated. The oncoprotein, Bcl-2, counters apoptosis in many instances, and when expressed in malignant cells often renders chemotherapy ineffective. Bcl-2 also provokes temporary refractoriness to mitogen stimulated cell proliferation but how this effect relates to its anti-apoptotic function was not previously clarified. In this proposal, the investigators now demonstrate that Bcl-2 in fact possesses two separate functions; ie. it increases a cell's inherent resistance against programmed cell death, and independently also delays cell proliferation. This suggests a metazoan strategy in which proliferation of cells with cell-autonomous resistance to apoptosis is inherently restricted, and argues that an overriding mitogenic signal and/or selective disabling of Bcl-2's antiproliferative effect is required for the proliferation of Bcl-2 expressor cells. The temporal correlation seen between Bcl-2's phosphorylation and its effect on cell proliferation suggests this post-translational modification may represent one such inactivation mechanism. Bcl-2 kinase initiated inactivation of Bcl-2's antiproliferative function may contribute to the secondary malignant transformations of Bcl-2 expressing indolent tumors, such as follicular lymphoma. Their proposed research program aims to examine the relation of Bcl-2's phosphorylation to its antiproliferative effect, to identify the kinase responsible for Bcl-2's phosphorylation and to examine its role in malignant transformation of Bcl-2 expressing indolent tumors. In addition, the wish to identify the mechanism by which Bcl-2 delays cell cycle progression.