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Overexpression of the oncoprotein BCL‐XL inhibits thioridazine‐induced apoptosis in acute promyelocytic leukemia cells (LB162)
Author(s) -
Moraes Vivian,
Rodrigues Tiago
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.lb162
Subject(s) - apoptosis , programmed cell death , annexin , flow cytometry , biology , viability assay , acute promyelocytic leukemia , trypan blue , cancer research , microbiology and biotechnology , propidium iodide , cell culture , biochemistry , retinoic acid , genetics
The development of resistance to chemotherapeutic agents is one of the main problems in Oncology. Therefore, the improvement of novel antitumor drugs and the knowledge of new drugs and/or new targets in tumor cells are the major goal in this field. During the last years, mitochondria have emerged as an important cancer drug target, since they control several processes that are disrupted in tumor cells, including the control of cell death/survival by the BCL‐2 family proteins. Studies from our group have evidenced relevant biological effects of the antipsychotic thioridazine (TR) in tumor cells associated to mitochondrial dysfunction. In this work we evaluated the effects of BCL‐XL overexpression in the TR‐induced cell death in an acute promyelocytic leukemia model. Parental and overexpressing BCL‐XL HL‐60 cells were cultivated in RPMI1640 plus 10% BFS and antibiotics. Cell viability was evaluated by MTT and trypan blue assays. Also, cells were double stained with Annexin V‐FITC/PI and analyzed by flow cytometry. ROS generation and mitochondrial membrane potential were estimated by flow cytometry using CM‐H2DCFDA and JC‐1, respectively. The incubation of HL‐60 cells with TR for 24h resulted in cell death with an EC50 of 1.9 µM. The double staining cytometry revealed a predominant annexin V‐FITC positive and PI negative staining, indicative of apoptosis. TR‐induced HL‐60 cell death was accompanied by ROS generation and dissipation of mitochondrial transmembrane potential. The overexpression of BCL‐XL increased 7‐fold the EC50 (14.8 µM) for TR‐induced cell death and abolished ROS generation and mitochondrial depolarization. The induction of apoptosis in this model highlights the antitumor potential of TR and these results demonstrate the involvement of mitochondria and ROS unbalance in the TR‐induced apoptosis, as well as its regulation by BCL‐XL. Grant Funding Source : Supported by FAPESP