The TRAIL apoptotic pathway mediates proteasome inhibitor induced apoptosis in primary chronic lymphocytic leukemia cells.

The proteasome inhibitors are a new class of antitumor agents. These inhibitors cause the accumulation of many proteins in the cell with the induction of apoptosis including TRAIL death receptors DR4 and DR5, but the role of the TRAIL apoptotic pathway in proteasome inhibitor cytotoxicity is unknown. Herein, we have demonstrated that the induction of apoptosis by the proteasome inhibitors, MG-132 and PS-341 (bortezomib, Velcade), in primary CLL cells and the Burkitt lymphoma cell line, BJAB, is associated with up-regulation of TRAIL and its death receptors, DR4 and DR5.

Lysophosphatidic acid (LPA) protects primary chronic lymphocytic leukemia cells from apoptosis through LPA receptor activation of the anti-apoptotic protein AKT/PKB.

Lysophosphatidic acid (LPA) protects epithelial and fibroblast cell lines from apoptosis. In B-cells, LPA acts as a growth factor promoting cell proliferation. Chronic lymphocytic leukemia (CLL) is characterized by the accumulation of CD19+/CD5+ B-lymphocytes primarily through a block in apoptosis.

Changes in the apoptotic and survival signaling in cancer cells and their potential therapeutic implications.

In normal healthy tissues, an equilibrium is established between cell death and survival. This equilibrium ensures that cells survive in the right milieu, but undergo programmed cell death (apoptosis) when damaged, or when the environment is no longer supportive. Diseases may occur with alterations in this homeostasis.

Role of the TRAIL/APO2-L death receptors in chlorambucil- and fludarabine-induced apoptosis in chronic lymphocytic leukemia.

The standard treatments for chronic lymphocytic leukemia (CLL) include the alkylating agent chlorambucil (CLB) and the nucleoside analog fludarabine (F-ara-AMP, Flu). Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a death receptor ligand that induces apoptosis preferentially in tumors. However, CLL cells seem to be resistant to TRAIL-induced apoptosis.