Journal of Blood & Lymph

Evaluation of DNA Methylation and Genes Expression JAK2 and STAT3 Gene in Acute Lymphoblastic Leukemia

Abstract

Majid Naderi, Maryam Emami*, Mohammad Shojaei, Tahmine Davoodi and Dor Mohammad Kordi Tamandani*

Acute Lymphoblastic Leukemia (ALL) is the most prevalent malignancy among children. The primary therapeutic modality involves the administration of induction chemotherapy alone or in combination with diverse curative strategies. Existing evidence suggests that epigenetic mechanisms may serve as mediators of the influence of inherited genetic variations on phenotypic characteristics. Consequently, our investigation aimed to ascertain the potential role of DNA methylation in mediating the impact of genetic risk loci on childhood ALL. In mammals, the JAK/STAT pathway represents the principal signaling mechanism for a wide array of cytokines and growth factors. Activation of JAK induces cell proliferation, migration, differentiation, and apoptosis. A multitude of therapeutic interventions have been devised to modulate this signaling pathway, exhibiting varying degrees of efficacy and shortcomings. Pioneeringly, this study sheds light on the methylation status of JAK2 and STAT3, as well as the mRNA expression profiles, in ALL patients both prior to and following administration of the drug. We examined to determine whether there were any alterations in methylation and gene expression between the two genes during chemotherapy treatment.

This study, which took place from 2015 to 2017, utilized a case-control design. It included 50 blood samples from individuals recently diagnosed with Acute Lymphoblastic Leukemia (ALL) who had not yet received any chemotherapy drugs. After a two-month period of receiving the drug, these samples were retested. The study population consisted of 23 males and 27 females with a mean age of 7.52 ± 4.13. Additionally, 50 blood samples from healthy volunteers without any significant medical conditions were included in the study. This control group also consisted of 23 males and 27 females, with a mean age of 12.36 ± 5.63. All samples were stored at a temperature of -80°C until molecular analysis could be conducted. The methylation frequency of the JAK2 gene was found to be 35 (70%) in the blood sample taken from the newly diagnosed patient (referred to as sample1), 18 (36%) in the blood sample taken after the patient received chemotherapy (referred to as sample 2), and 3 (6%) in the blood samples from the healthy controls. The STAT3 gene exhibited a methylation rate of 54% (N=27) in sample1, 32% (N=16) in sample 2, and 4% (N=2) in the control group. A comparison between methylated and unmethylated samples indicated a significant disparity between the cases and controls in terms of JAK2 (OR1=36.55; 95%CI: 9.81 to 136.10, P < 0.0001) and STAT3 (OR1=28.17; 95% CI: 6.16 to 128.80, P<0.0001). Additionally, a notable distinction was observed between patients who underwent chemotherapy and the healthy individuals in relation to JAK2 (OR2=8.81; 95%CI: 2.39 to 32.40, P=0.0011) and STAT3 (OR2=11.29; 95%CI: 2.43 to 52.38, P=0.0020). In alternative terms, when we assessed the methylation status in patients subsequent to the administration of a chemotherapy drug in relation to their pre-treatment condition, a statistically significant finding was observed in JAK2 (OR3=4.14; 95%CI: 1.79 to 9.57, P=0.0009). However, no disparities were identified in STAT3 (OR3=2.49; 95%CI: 1.10 to 5). Within the framework of this investigation, we examined the disparity between the methylation of promoter DNA and the expression of genes within this pathway among patients who received the drug on the initial day, as well as the disparities with the control group. Chemotherapy drugs impeded the cell cycle and mitigated the adverse effects, particularly in the context of bone marrow metastasis, which was reliant on patient relapse in subsequent years.