Telomerase activation is regulated by the expression of human telomerase reverse transcriptase (hTERT) and is a key step in the development of human cancers. Interferon-gamma (IFN-gamma) signaling induces growth arrest in many tumors through multiple regulatory mechanisms. The p27 tumor suppressor protein inhibits the formation of tumors through the induction of cell cycle arrest and/or apoptosis. We demonstrate here that p27Kip1 inhibits hTERT mRNA expression and telomerase activity through post-transcriptional up-regulation by IFN-gamma/IRF-1 signaling. The ectopic expression of p27 suppressed hTERT expression and telomerase activity in human cervical cancer cell lines, HeLa and HT3. Furthermore, hTERT promoter activity of mouse embryonic fibroblasts (MEFs) deficient in p27 (p27-/- MEFs) was significantly higher than that of wild-type MEFs. Overexpression of p27 suppressed hTERT promoter activity and telomerase activity of p27-/- MEFs. In addition p27 down-regulated E7 protein expression and in transiently transfected HeLa cells, E7 increased hTERT promoter activity. In conclusion, we propose that inhibition of the hTERT expression and telomerase activity may be a novel tumor suppressor function of p27.
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http://dx.doi.org/10.1016/j.febslet.2005.01.005 | DOI Listing |
J Phys Chem B
January 2025
College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China.
Under conditions that are close to the real cellular environment, the human telomeric single-stranded overhang (∼200 nt) consisting of tens of TTAGGG repeats tends to form higher order structures of multiple G-quadruplex (G4) blocks. On account of the higher biological relevance of higher order G4 structures, ligand compounds binding to higher order G4 are significant for the drug design toward inhibiting telomerase activity. Here, we study the interaction between a cationic porphyrin derivative, 5,10,15,20-tetra{4-[2-(1-methyl-1-piperidinyl)propoxy]phenyl}porphyrin (T4), and a human telomeric G4-dimer (AG(TAG)) in the mimic intracellular molecularly crowded environment (PEG as a crowding agent) and K or Na solution (i.
View Article and Find Full Text PDFCells
January 2025
The Shapiro Family Laboratory of Viral Oncology and Aging Research, UCLA School of Dentistry, University of California, 714 Tiverton Ave, Los Angeles, CA 90095, USA.
Doxorubicin is a highly effective anticancer agent, but its clinical use is restricted by severe side effects, including atherosclerosis and cardiomyopathy. These complications are partly attributed to doxorubicin's ability to induce endothelial-to-mesenchymal transition (EndMT) in vascular endothelial cells, a critical process in the initiation and progression of atherosclerosis and cardiomyopathy. GV1001, a multifunctional peptide with anti-inflammatory, anti-cancer, antioxidant, and anti-Alzheimer's properties, has demonstrated inhibition of EndMT.
View Article and Find Full Text PDFJMIR Aging
January 2025
Faculty of Medicine, Department of Statistics, University of Salamanca, Salamanca, Spain.
Background: Telomere length (TL) is a marker of cellular health and aging. Physical exercise has been associated with longer telomeres and, therefore, healthier aging. However, results supporting such effects vary across studies.
View Article and Find Full Text PDFNat Commun
January 2025
Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, USA.
Biogenesis of human telomerase requires its RNA subunit (hTR) to fold into a multi-domain architecture that includes the template-pseudoknot (t/PK) and the three-way junction (CR4/5). These hTR domains bind the telomerase reverse transcriptase (hTERT) protein and are essential for telomerase activity. Here, we probe hTR structure in living cells using dimethyl sulfate mutational profiling with sequencing (DMS-MaPseq) and ensemble deconvolution analysis.
View Article and Find Full Text PDFCirc Res
January 2025
Division of Cardiology, Department of Medicine, Pittsburgh Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, PA. (R.A.C., C.C.C., R.W., A.C., C.B., C.R., W.J.M., M.J. Bashline, A.P., A.M.P., P.B., M.J. Brown, C.S.H.).
Background: Calcific aortic valve disease is the pathological remodeling of valve leaflets. The initial steps in valve leaflet osteogenic reprogramming are not fully understood. As TERT (telomerase reverse transcriptase) overexpression primes mesenchymal stem cells to differentiate into osteoblasts, we investigated whether TERT contributes to the osteogenic reprogramming of valve interstitial cells.
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