The maintenance of telomeres, nucleoprotein structures that constitute the ends of eukaryotic chromosomes, regulates many crucial cellular functions and might, in multicellular organisms, participate in the control of complex phenotypes such as aging and cancer. Stabilization of telomere length is strongly associated with cellular immortalization, and constitutive telomerase activation occurs in most human cancers. Such observations form the basis for the prevailing model that postulates that alterations in telomere biology both suppress and facilitate malignant transformation by regulating genomic stability and cell life span. However, recent findings suggest that telomere maintenance might not be an obligate requirement for initial tumor formation in some settings and that telomerase activation contributes to tumorigenesis independently of its role in maintaining telomere length. These recent developments indicate that our understanding of telomere biology remains incomplete and implicate additional complexity in the relationships among telomeres, telomerase and cancer.
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http://dx.doi.org/10.1016/s0962-8924(03)00085-0 | DOI Listing |
World J Gastrointest Oncol
January 2025
Department of Clinical Laboratory, Affiliated Hospital of North Sichuan Medical College, Nanchong 637000, Sichuan Province, China.
Background: Esophageal squamous cell carcinoma (ESCC) is a malignant tumor with high morbidity and mortality, and easy to develop resistance to chemotherapeutic agents. Telomeres are DNA-protein complexes located at the termini of chromosomes in eukaryotic cells, which are unreplaceable in maintaining the stability and integrity of genome. Telomerase, an RNA-dependent DNA polymerase, play vital role in telomere length maintain, targeting telomerase is a promising therapeutic strategy for cancer.
View Article and Find Full Text PDFBiol Direct
January 2025
Department of Clinical Laboratory, Affiliated Hangzhou First People's Hospital, School of Medicine, Westlake University, Hangzhou, Zhejiang, China.
Thioredoxin1 (TRX1) and telomerase are both attractive oncology targets that are tightly implicated in tumor initiation and development. Here, we reported that the 6-dithio-2-deoxyguanosine analog thiotert exhibits an effective cytotoxic effect on myelodysplastic syndromes (MDS) cell SKM-1 and lymphoma cell U-937. Further studies confirmed that thiotert effectively disrupts cellular redox homeostasis, as evidenced by elevated intracellular reactive oxygen species (ROS) levels, increased MnSOD, accelerated DNA impairment, and activated apoptosis signal.
View Article and Find Full Text PDFMech Ageing Dev
January 2025
Department of Medicine, Divisions of Geriatric Medicine and Gerontology, the Department of Physiology and Biomedical Engineering, and the Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, Minnesota. Electronic address:
Preclinical models of age-related osteoporosis have been developed based on the accumulation and clearance of senescent cells. The former include animal models based on telomere dysfunction and focal radiation; the latter based on genetic and pharmacological targeting (i.e.
View Article and Find Full Text PDFTo maintain genome stability, proliferating cells must enact a program of telomere maintenance. While most tumors maintain telomeres through the action of telomerase, a subset of tumors utilize a DNA-templated process termed Alternative Lengthening of Telomeres or ALT. ALT is associated with mutations in the ATRX/DAXX/H3.
View Article and Find Full Text PDFAlternative Lengthening of Telomeres (ALT) is a homologous recombination-dependent telomere elongation mechanism utilized by at least 10-15% of all cancers. Here we identified that the DNA topoisomerase, TOP3A is enriched at the telomeres of ALT cells but not at the telomeres of telomerase-positive (Tel) cancer cells. We demonstrate that TOP3A stabilizes the shelterin protein TERF2 in ALT cancer cell lines but not in Tel cells and that long non-coding telomere transcribed RNA (TERRA) enrichment at telomeres depends upon TOP3A.
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