Journal of Clinical and Diagnostic Research (Dec 2021)
Expression of Poly(A)-Specific Ribonuclease in Solid Tumours and Haematopoietic Malignancies
Abstract
Introduction: Ribonucleases (RNases) are enzymes involved in degradation of excess messenger Ribonucleic Acid (mRNA) and deadenylation of the poly(A) tail is the most common mechanism involved in mRNA degradation. Among the various RNases involved in deadenylation-dependent mRNA decay, Poly(A)-Specific Ribonuclease (PARN) plays the major role in the deadenylation-mediated mRNA decay. Although PARN is primarily involved in mRNA stability, recent studies suggest other functions of PARN including a role in telomere maintenance, DNA-damage response, and p53 regulation. Altered expression of PARN was also observed in cancers including acute leukaemia, lung squamous cell carcinoma and gastric cancer. Aim: To determine the levels of PARN transcripts in solid tumours and haematopoietic malignancies. Materials and Methods: This study was conducted on a cohort obtained from the Department of Oncology at Justice KS Hegde Charitable hospital in Mangaluru, Karnataka, India during January 2017 to June 2017. A total of 26 clinical samples and 14 controls were included. The expression level of PARN in plasma and tissue samples obtained from patients with solid organ tumours and haematopoietic malignancies were analysed by quantitative real-time Polymerase Chain Reaction (PCR) by calculating relative expression using Microsoft excel 2010. Results: A consistent down regulation of PARN in 88.23% (15 out of 17) of the samples were observed. All the plasma samples (100%, 10 out of 10) obtained from the lung cancer cases, showed down regulation of PARN at statistically significant level, regardless of the subtype of the cancer. In case of haematopoietic malignancies, PARN transcript level was down regulated in five out of seven samples analysed (71.42%), with statistically significant decrease in three of them. Conclusion: Despite a small sample size, the data presented here show that PARN is down regulated in solid organ cancers, suggesting a tumour-suppressive function of PARN. Screening of a large number of samples would be required to evaluate the true potential of PARN as a novel biomarker in solid organ and haematopoietic cancer.
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