en عمومى General پژوهشي Research <div><strong>Background: </strong>Due to the estrogen participation in modulating the proliferation and commitment of stem cells and the effects of miR-21 and miR-155 expression on reduced proliferation and colony formation of acute myeloid leukemia (AML), the aim of the present study was to evaluate the effect of estradiol on expression of miR-21 and miR-155 in the NB4 cell line, as an acute promyelocytic leukemia (APL).<br> <strong>Materials and Methods: </strong>In the present experiment, NB4 cells were treated with different quantities of estradiol (5, 25, 50, 75, 100, 150, 200, 250 &mu;g/ml) and vehicle control for 24 and 48 hours. Viability, apoptosis, and cellular proliferation were estimated by trypan blue exclusion, flow cytometry, and MTT assays, respectively. The level of miR-155 and miR-21 expression was studied using absolute quantitative real-time PCR.<br> <strong>Results: </strong>Results showed that estradiol in the effective dose (200 &mu;g/ml) led to decreased cellular viability (in a dose dependent manner, P = 0.004) and apoptosis of NB4 cells. In addition, the expressions of miR-155 and miR-21 were significantly and dose-dependently decreased (p<0.05).<br> <strong>Conclusion: </strong>Estradiol at the effective dose caused apoptosis in NB4 cell line. This substance can be used as a drug for the treatment of APL. However, further assessments are needed to support the effectiveness of estradiol in the treatment of APL.<br> &nbsp;</div> cute Myeloid Leukemia (AML), Estradiol, MiR-155, MiR-21 49 56 http://ijpho.ssu.ac.ir/browse.php?a_code=A-10-686-2&slc_lang=en&sid=1 Robab Naghibzadeh robab.naghibzadeh@gmail.com No Department of Hematology, School of Para Medicine, Bushehr University of Medical Sciences, Bushehr, Iran Bushehr University of Medical Sciences Narges Obeidi nobeidi@yahoo.com 0000-0001-8087-2850 Yes Department of Hematology, School of Para Medicine, Bushehr University of Medical Sciences, Bushehr, Iran Bushehr University of Medical Sciences Alireza Farsinejd farsinezahad239@yahoo.com No Department of Hematology and Medical Laboratory Sciences, Faculty of Allied Medical Sciences, Kerman University of Medical Sciences, Kerman, Iran Kerman University of Medical Sciences Gholamreza Khamisipour gh.khamisi@gmail.com No Department of Hematology, School of Para Medicine, Bushehr University of Medical Sciences, Bushehr, Iran Bushehr University of Medical Sciences Masoud Tohid Far gtohidfar@yahoo.com No Department of Hematology and Medical Laboratory Sciences, Faculty of Allied Medical Sciences, ShahidBeheshti University of Medical Sciences, Tehran, Iran Shahid Beheshti University of Medical Sciences