Telomeres are often considered as the 'ageing clock' that determines the lifespan at the cellular level, forming the ends of a chromosome, which shorten each time the cell divides itself to the point where they become so short the cell is unable to divide itself further. Telomere length alteration is often linked with lifestyle factors such as age, obesity, exposure to pesticides and pollution, depression, unhealthy diet, lack of exercise, and stress. The current review discusses the mechanism of telomere shortening in relation to ageing and lifestyle factors in general and its association with chronic diseases like diabetes which may influence the health and lifespan of an individual by increasing telomere shortening. Accelerated or excessive telomere shortening is also associated with the early onset of age-related disorders globally and, hence, reduced lifespan of individuals. Upregulated Telomerase activity and reactivation of telomeres is observed in > 70 % of cancer patients by TERT point mutations, rearrangements, DNA amplifications, and transcript fusions, making it a useful marker in diagnosis and prognosis of various cancers. The study presents a systematic review of the unregulated Telomere activity with progression of various cancer and extrapolation of suitable pathways and prognostic information correlated with mRNA levels of TERT, which are critical among thymic epithelial tumors (TETs). In most cancers, unlimited proliferation is due to the reactivation of reverse transcriptase gene TERT. All these observations are comprehensively presented in the paper and might be useful for researchers working in the field of telomere dynamics and finding the correlation of age shortening with mRNA expression profiling.
Keywords: Ageing; Cancer; Diabetes; Lifestyle; MRNA expression profiling; Telomere shortening.
Copyright © 2022 Elsevier Ltd. All rights reserved.