ABSTRACT
<p><b>OBJECTIVE</b>The proto-oncogene c-Met was found to express on human laryngeal carcinoma Hep-2 cell line in previous research. In the present study, the author further examined whether inhibition of c-Met by RNA interference (RNAi) might inhibit biologic activity of Hep-2 cell line in vitro and proliferation using a murine laryngeal carcinoma model.</p><p><b>METHODS</b>RNAi plasmid that can express small interfering RNA targeting c-Met or siRNA that did not match any known human coding mRNA(control siRNA plasmid)was designed, constructed, and transfected into Hep-2 cell line by using cationic liposome Lipofectamine2000 as transfecting agent. In vitro, the transfection efficacy was tested by RT-PCR and Western Blot method, then elected the most inhibitive c-Met-siRNA sequence. Cell proliferation, movement and invasion were studied using MTT, cell migration assay and cell invasion assay, respectively. The Hep-2 cells were transplanted into nude mice, then the time of tumor formation and growth were observed. After tumor formation, c-Met-siRNA was given as the anti-tumor therapy. Expression of c-Met, MMP-9 and VEGF were detected by Western Blot method.</p><p><b>RESULTS</b>After the pSilencer2.0/c-Met-shRNA recombinant plasmid transfection into laryngeal carcinoma Hep-2 cells, the expression of mRNA and protein of c-Met decreased significantly in Hep-2 cells. On the 35th day after tumor vaccination, the tumor volume was (138 ± 27) mm³ in c-Met-siRNA transfection group, Which was diminished significantly in contrast with control group (P < 0.01). The expression of c-Met, MMP-9 and VEGF in the tumor of experiment group was decreased significantly, respectively (P < 0.05).</p><p><b>CONCLUSIONS</b>The results indicated that c-Met-siRNA can down-regulate the expression of c-Met and markedly inhibit laryngeal carcinoma Hep-2 cell proliferation, movement and invasion and the growth of transplantation tumor of nude mice. The siRNA expressing plasmid mediated gene therapy might be a new strategy in targeting molecular therapy of cancer of larynx.</p>