Down-Regulation of Ribosomal S6 kinase RPS6KA6 in Acute Myeloid Leukemia Patients


Mohammad Rafiee, M.Sc, 1Mohammad Reza Keramati, M.D, 2,*Hosein Ayatollahi, M.D, 2Mohammad Hadi Sadeghian, M.D, 2Mohieddin Barzegar, M.Sc, 1Ali Asgharzadeh, M.Sc, 1Mohsen Alinejad, M.Sc, 1
Hematology Lab, Imam Reza Hospital, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
Cancer Molecular Pathology Research Center, Ghaem Hospital, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
Hematology Lab, Imam Reza Hospital, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
Cancer Molecular Pathology Research Center, Ghaem Hospital, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
*Corresponding Address: Cancer Molecular Pathology Research Center Ghaem Hospital Faculty of Medicine Mashhad University of Medical Sciences Mashhad Iran Email:Keramatimr@mums.ac.ir
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Abstract

Objective

Signaling pathways such as extracellular regulated kinase/mitogen activated protein kinase (ERK/MAPK) have increased activity in leukemia. Ribosomal 6 kinase (RSK4) is a factor downstream of the MAPK/ERK pathway and an important tumor suppressor which inhibits ERK trafficking. Decrease in RSK4 expression has been reported in some malignancies, which leads to an increase in growth and proliferation and eventually poor prognosis. In this study we measured RSK4 expression rate in acute myeloid leukemia (AML).

Materials and Methods

This cross-sectional study was undertaken in 2013-2014 at Ghaem Hospital in Mashhad, Iran, on 40 AML patients and 10 non-AML patients as the control group. The expression rate was measured by real-time polymerase change reaction (PCR) and employing the ΔΔCT method. Data were analyzed using Mann-Whitney and Spearman tests using SPSS (version 11.5).

Results

Expression rate of RSK4 was significantly decreased in the AML group in comparison with the non-AML group (P<0.001). There was also a significant decrease in RSK4 expression in AML with t(15;17) in comparison to other translocations (P=0.004).

Conclusion

We detected a down-regulation of RSK4 in AML patients. This may lead to an increase in the activity of the ERK/MPAK pathway and exacerbate leukemogenesis or the prognosis of the patients.