Human telomerase reverse transcriptase regulates MMP expression independently of telomerase activity <i>via</i> NF‐κB‐dependent transcription

Telomerase plays a pivotal role in the pathology of aging and cancer by controlling telomere(definition) length and integrity. However, accumulating evidence indicates that telomerase reverse transcriptase may have fundamental biological functions independent of its enzymatic activity in telomere maintenance. In this study, the ectopic expression of human telomerase reverse transcriptase (hTERT) and its catalytic mutant hTERT K626A induced cancer cell invasion accompanied by the up-regulation of the metalloproteinases (MMPs) MMP1, -3, -9, and -10. Both hTERT and hTERT K626A induced MMP9 mRNA expression and promoter activity in an NF-κB-dependent manner. hTERT and hTERT K626A also regulated the expression of several NF-κB target genes in cancer cell lines. Furthermore, both hTERT and hTERT K626A interacted with NF-κB p65 and increased NF-κB p65 nuclear accumulation and DNA binding. A mammalian 1-hybrid assay showed a functional interplay between hTERT and NF-κB p65 that may mediate NF-κB-dependent transcription activation in cells. Together, these data reveal a telomere-independent role for telomerase as a transcriptional modulator of the NF-κB signaling pathway and a possible contributor to cancer development and progression.