Abstract

 Background and Objectives

 Acute Promyelocytic Leukemia (APL) is one subtype of acute myeloblastic leukemia it responds to differentiation using All-Trans Retinoic Acid (ATRA). Recently, arsenic trioxide (As₂O₃) has been added to this method. The cellular mechanism of differentiation therapy by arsenic is not yet clear. We decided to study the relationship between cell differentiation using arsenic trioxide and nucleostemin gene as a proliferation marker.

 Materials and Methods

 In this descriptive study, we treated NB4 cell (a cell line in APL) with 0.5, 1, and 2 µM of arsenic trioxide in 6 well plates for five days. Then, cellular differentiation was assessed by flowcytometry for CD11b. Nucleostemin gene expression was also assessed by Real Time PCR.

 Results

 According to the results, cell proliferation has occurred by 0.5 µM arsenic trioxide and no differentiation was observed during 10 days of culture. With 1 µM concentration of arsenic, CD11b has raised from 5.2% to 13.6% during five days of culture (p < 0.001). Morever, 1 µM of arsenic caused decrease in nucleostemin gene copy number from 130 to 70.

 Conclusions

 According to the results, 1 µM of arsenic has increased CD11b in the cells and caused a partial differentiation during five days of culture. Increase in CD11b marker has also been associated with decrease in nucleostemin gene expression as a proliferation marker.

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 Key words : Leukemia, Promyelocytic, Acute, arsenic trioxide, RT- PCR�