Clinical and metabolic effects of miR-26a, miR-16 and let-7 microRNAs in acromegaly patients

Background and aim: MicroRNAs (miRNA) are small nucleotide sequences that affect gene expression in cells at the posttranscriptional level. Some miRNAs behave like oncogenes, while others behave like tumor suppressors. In this study, it was aimed to investigate the role of miRNAs in tumor development and its effects on clinical and metabolic parameters of the patients with acromegaly. Methods: 39 patients diagnosed with acromegaly (20 F / 19 M, mean age 51.6 ± 10.1 years) and 39 age- and gender-matched healthy controls (27 F/ 12 M, mean age 52.1 ± 12 years) were included in the study. The levels of miR-16, miR-26a and let-7 were measured in peripheral blood by real-time PCR methods. Demographic features of the patients, radiological features of the adenoma, treatment modalities and comorbidities of the patients were evaluated. The relationship between these parameters and miRNAs was evaluated. Results: While there was no significant difference in miR-16 and miR-26a levels between acromegalic patients and the control group, let-7 levels were found to be lower in acromegalics compared to the control group [0.945 (0.29-5.77) vs.1.261 (0.25-3.1); p = 0.053]. There was no effect of miRNAs on adenoma size, optic chiasm compression and cavernous sinus invasion of the adenoma. Regarding the effects of miRNAs on need of medical treatment, miR26a expression is demonstrated to be increased in patients who use medical treatment (N: 26, 66.6%) [1.22 (0.63- 5.98) vs.0.74 (0.51-2.62); p=0.004] whereas miR-16 [0.95 (0.34-5.27) vs 0.74 (0.44- 2.65); p: 0.121] and let-7 [0.75 (0.29-5.77) vs. 0.63 (0.29-1.44); p:0.095] were found to be similar in both groups. When the patients were evaluated according to the presence of of coronary artery disease, hypertension, hyperlipidemia, Type 2 diabetes mellitus, multinodular goiter, malignancy and colonic polyps, no statistically significant difference was found between the groups in all three miRNA levels. Conclusion: Decreased expression of let-7 miRNA levels, which is known to have a tumor suppressor feature, suggests that it may have a role in tumor development in acromegaly. While these was no effect of these miRNAs on the development of clinical features and comorbidities of acromegalic patients, increased miR-26a expression in patients receiving medical therapy supports the potential role of miR- 26a in determining the long-term prognosis of acromegalic patients. Key words: Acromegaly, microRNA, miR-26a, miR-16, let-7