Background and Aim: Acute promyelocytic leukemia (APL) is a distinct subtype of acute myeloid leukemia. APL is characterized by a balanced reciprocal translocation between chromosomes 15 and 17, t(5;17)). Important therapeutic strategies for this disease are ATRA and Arsenic trioxide. To eliminate tumor cells with arsenic, high dose of arsenic is needed. But high dose is toxic for normal tissue. The purpose of this study is Assessment of effect of low dose of arsenic trioxide in combination with AZT on NB4 cell line (APL cell line) to reduce toxic effect of high dose arsenic.

Materials and Methods: In this study after NB4 cell line culture and proliferation, the cells treated with low dose of arsenic trioxide(0.5µM) in combination with different doses of AZT(50, 100, 200 µM) and then viability and metabolic activity was assessed by try pan blue and MTT assay respectively.

Results: Low dose of arsenic (0.5µm) alone and in combination with dose of 50µm of AZT has little effect on viability and metabolic activity but in combination with higher dose of AZT has significant effect on viability and metabolic activity and both viability and metabolic activity significantly reduced.

Conclusion: Different apoptosis- induced mechanisms cause apoptosis by arsenic and AZT. Since some of these mechanisms between AZT and arsenic are similar, so maybe these similar mechanisms cause synergic effect and significant reduction of viability and metabolic activity in combination of these two drugs.