Human telomerase reverse transcriptase regulates cyclin D1 and G1/S phase transition in laryngeal squamous carcinoma.

Conclusion: Down-regulating human telomerase reverse transcriptase (hTERT) expression will significantly suppress the cell viability of laryngeal squamous cell carcinoma Hep-2, which was mainly due to the inhibition of cyclin D1 and thus G1/S phase transition. Objective: Small-interfering RNA (siRNA) targeting hTERT can arrest the cell cycle of cancer cells, as well as inhibit telomerase activity and cell viability. However, the precise mechanisms still remain unclear. Here, we investigate the regulatory role of hTERT in cyclin D1 in laryngeal squamous carcinoma. Methods: Short hairpin RNAs (shRNAs) specifically targeting hTERT were constructed and expressed in Hep-2 cells. Cell proliferation was measured by CCK-8 assay. Expression of hTERT, cyclin D1, cyclin E, c-myc, and GAPDH was detected by RT-PCR and Western blot; cyclin D1 and hTERT proteins in laryngeal squamous carcinoma tissue microarray were analyzed by quantum dots immunofluorescence. Results: hTERT silence by shRNAs decreased the proliferation of Hep-2 cells by 76.8% at day 4 (96 h). Furthermore, transfection with hTERT shRNA for 48 h also significantly reduced expression of hTERT, cyclin D1, and c-Myc, but not cyclin E. Quantum dots immunofluorescence analysis of 36 laryngeal squamous carcinoma tissue samples found that hTERT expression was highly correlated with cyclin D1 expression. [ABSTRACT FROM AUTHOR]

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