Signal transduction-related gene transfer leads to inhibition of proliferation and induction of differentiation in laryngeal squamous cell carcinoma in vitro

The aim of this study is to target the interference therapy of signal transduction which is a novel therapeutic strategy in laryngeal squamous cell carcinoma (LSCC). We successfully constructed recombinant adenoviruses Ad-p14^ARF, and Ad-antisense EGFR using AdEasy-1 vector System. Clonogenic cell assay, western blotting assay, 3′(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, flow cytometer (FCM) assay, and immunocytochemical technique were designed to examine the inhibition of proliferation, protein expression of p14^ARF and EGFR and induction of differentiation, respectively. Furthermore the synergistic effect of Ad-p14^ARF and Ad-antisense EGFR on Hep-2 cell was examined. We successfully used AdEasy-1 vector system to construct recombinant adenoviruses Ad-p14^ARF and Ad-antisense EGFR. The activity of proliferation of Hep-2 cells was inhibited markedly by infecting Ad-p14^ARF or Ad-antisense EGFR by comparing Ad-sense EGFR (P = 0.005) with vector control (Ad-Ctrl) (P = 0.005) and with PBS (P = 0.003). This effect, combining Ad-antisense-EGFR with Ad-p14^ARF became more noticeable than alone (P = 0.01, P = 0.02, respectively). P14 (ARF) protein overexpression, EGFR protein down expression, and inhibition of proliferation were observed in Hep-2 cells infected by either Ad-p14^ARF or Ad-antisense EGFR. FCM revealed that the proportion of apoptosis cells transfected by Ad-p14^ARF and Ad-antisense EGFR increased more obviously than the control. The proportion of (Hep-2 cells in) G₀/G₁ phases was increased by up to 78.5, 77.7, and 86.9% in Ad-antisense EGFR, Ad-p14^ARF, and Ad-antisense EGFR + Ad-p14^ARF, respectively. Our findings demonstrated that not only EGFR but p14^ARF also plays a major role on the genesis and in modulating the cell growth and differentiation of human laryngocarcinoma. They efficaciously blocked the signal transduction of human laryngocarcinoma cell, and may therefore, be an effective potential target of gene therapy to prevent human laryngocarcinoma cell proliferation.