1. Phenylarsine Oxide (PAO) More Intensely Induces Apoptosis in Acute Promyelocytic Leukemia and As2O3-Resistant APL Cell Lines than As2O3by Activating the Mitochondrial Pathway
- Author
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Masato Maekawa, Miki Kobayashi, Kazunori Ohnishi, Akihiro Takeshita, Tomoki Naoe, Satoki Nakamura, Toshinobu Horii, Kensuke Naito, Hideharu Hayash, Kaori Shinjo, Naohi Sahara, Ryuzo Ohno, Kunio Kitamura, and Kazuyuki Shigeno
- Subjects
Acute promyelocytic leukemia ,Cancer Research ,bcl-X Protein ,Down-Regulation ,Apoptosis ,Biology ,Arsenicals ,Membrane Potentials ,chemistry.chemical_compound ,Arsenic Trioxide ,Leukemia, Promyelocytic, Acute ,Cell Line, Tumor ,medicine ,Humans ,Cytotoxic T cell ,Cyclin D1 ,Phenylarsine oxide ,Cell Proliferation ,Dose-Response Relationship, Drug ,Cell growth ,Oxides ,Hematology ,medicine.disease ,Molecular biology ,Mitochondria ,Transplantation ,Leukemia ,Proto-Oncogene Proteins c-bcl-2 ,Oncology ,chemistry ,Biochemistry ,Drug Resistance, Neoplasm ,Cell culture - Abstract
We studied the cytotoxic effect of an organic arsenical compound, phenylarsine oxide (PAO) on an acute promyelocytic leukemia (APL) cell line (NB4) and an As2O3-resistant NB4 subline (NB4/As). Cell growth was inhibited by 50% (IC50) upon 2-day treatment with As2O3 or PAO at 0.54 and 0.06 microM, respectively in NB4 cells (P = 0.025), and 2.80 and 0.08 microM, respectively in NB4/As (P = 0.030). 0.1 microM PAO increased the proportion of hypodiploid cells (50.3%) by a greater degree than the same dose of As2O3 (3.8%) in NB4 cells. In NB4 cells, 0.1 microM PAO reduced the mitochondrial transmembrane potential (20.5% in a PI(negative)-Rhodamine123(low) fraction) by a greater degree than 1 microM As2O3 (7.1%). Western blotting showed that 0.1 microM PAO downregulated the expression of both Bcl-2 and Bcl-X(L) proteins, whereas I microM As2O3 downregulated only Bcl-2 expression. These results suggest that the cytotoxic effect of PAO on an APL cell line and As2O3-resistant subline is significantly higher than that of As2O3. PAO-induced apoptosis seems to be related to the activation of the mitochondrial pathway and downregulation of both Bcl-2 and Bcl-X(L). PAO is a considerable agent for relapsed/refractory APL and for purging APL cells following stem cell transplantation.
- Published
- 2004