gossypol-acetic-acid and Lymphoma--B-Cell

B-cell lymphoma 2 (Bcl-2) is a regulator protein involved in apoptosis. In the past few decades, this protein has been demonstrated to have high efficacy in cancer therapy, and several approaches targeting Bcl-2 have been tested clinically (e.g., oblimersen, ABT-737, ABT-263, obatoclax mesylate, and AT-101). This review reports potential Bcl-2 inhibitors according to current information on their underlying mechanism and the results of clinical trials. In addition, the function and mechanisms of other potentially valuable Bcl-2 inhibitors that did not show efficacy in clinical studies are also discussed. This summary of the development of Bcl-2 inhibitors provides worthwhile viewpoints on the use of biomedical approaches in future cancer therapy.

Topics: Aniline Compounds; Antineoplastic Agents; Apoptosis; Biphenyl Compounds; Cell Line, Tumor; Gossypol; Humans; Lymphoma, B-Cell; Nitrophenols; Piperazines; Proto-Oncogene Proteins c-bcl-2; Sulfonamides; Thionucleotides

Overexpression of antiapoptotic members of the Bcl-2 family are observed in approximately 80% of B-cell lymphomas, contributing to intrinsic and acquired drug resistance. Nullifying antiapoptotic function can potentially overcome this in-trinsic and acquired drug resistance. AT-101 is a BH3 mimetic known to be a potent inhibitor of antiapoptotic Bcl-2 family members including Bcl-2, Bcl-X(L), and Mcl-1. In vitro, AT-101 exhibits concentration- and time-dependent cytotoxicity against lymphoma and multiple myeloma cell lines, enhancing the activity of cytotoxic agents. The IC(50) for AT-101 is between 1 and 10 microM for a diverse panel of B-cell lymphomas. AT-101 was synergistic with carfilzomib (C), etoposide (E), doxorubicin (D), and 4-hydroxycyclophosphamide (4-HC) in mantle cell lymphoma (MCL) lines. In a transformed large B-cell lymphoma line (RL), AT-101 was synergistic when sequentially combined with 4-HC, but not when both drugs were added simultaneously. AT-101 also induced potent mitochondrial membrane depolarization (Delta Psi m) and apoptosis when combined with carfilzomib, but not with bortezomib in MCL. In severe combined immunodeficient (SCID) beige mouse models of drug-resistant B-cell lymphoma, 35 mg/kg per day of AT-101 was safe and efficacious. The addition of AT-101 to cyclophosphamide (Cy) and rituximab (R) in a schedule-dependent manner enhanced the efficacy of the conventional therapy.

Topics: Animals; Antibodies, Monoclonal; Antibodies, Monoclonal, Murine-Derived; Antineoplastic Agents, Phytogenic; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; BH3 Interacting Domain Death Agonist Protein; Biomimetics; Blotting, Western; Cell Line, Tumor; Cyclophosphamide; Disease Models, Animal; Flow Cytometry; Gossypol; Humans; In Vitro Techniques; Lymphoma, B-Cell; Membrane Potential, Mitochondrial; Mice; Microscopy, Confocal; Proto-Oncogene Proteins c-bcl-2; Rituximab; Xenograft Model Antitumor Assays