[Role of siRNA mediated matrix metalloproteinase-2 gene silencing in the inhibition of invasion and growth of laryngeal cancer cells].

Objective: To explore the inhibitory effect of matrix metalloproteinase-2 (MMP-2) gene silencing in vitro and in vivo on the invasion and growth of laryngeal cancer cells.

Methods: siRNA recombinant lentivirus targeting MMP-2 gene was transfected into Hep-2 cells, and MMP-2 protein expression was analyzed consequently by using western-blot. Invasive properties of transfectants were evaluated by Boyden assay. In addition, the lentivirus was intratumorally injected in a model of the grafted nude mouse and the morphological changes of transfectants were examined by transmission electron microscope. Finally, cell proliferation in xenografts was measured by immunolabeling of proliferating cell nuclear antigen (PCNA).

Results: Over 90% of target cancer cells were found to be transfected by MMP-2-RNAi-Lentivirus. Western-blot analysis revealed that none of transfectants expressed MMP-2 protein whereas most untreated cancer cells exhibited positive protein expression. Significant differences were found between the treated and untreated groups regarding the number of transfectants penetrating through an artificial basement in a Boyden chamber (12 +/- 4 vs 35 +/- 6, x +/- s, t = 14.492, P < 0.01), and the average value of weight [(1.186 +/- 0.225) g vs [(2.127 +/- 0.344) g] and volume [(0.974 +/- 0.216) cm3 vs (1.618 +/- 0.272) cm3] of the grafted tumors (t was 7.094 and 5.684, P < 0.01). The overall tumor inhibitive rate was about 44.2%. Transmission electron microscope showed an obviously decreased invasive feature of transfectants. Finally, the percentages of transfectants immunolabeled for PCNA were significantly lower in the treated group (49.588 +/- 6.995) than those (71.434 +/- 7. 043) in control one (t = 9. 573, P < 0.01).

Conclusions: The invasion, growth and proliferation of laryngeal cancer can be inhibited by siRNA mediated MMP-2 gene silencing. These data strongly suggest that MMP-2 gene silencing by siRNA technology could be a promising approach to cancer therapy.