| Hepatocyte growth factor (HGF), namely scatter factor (SF) is the strongest cytokine that stimulate hepatocyte regeneration. At first, it has ever been considered as the hepatocyte specificity cytokine incorrectly. Latter, its' effect of promoting caryocinesia and inducing morphogenesis on nephric tubule epithelium, alveolar epithelium, gastrointestinal tract mucosae epithelium and other epithelium cells was been discovered. HGF can promote tumor cell cleavage, induce tumor cell migration and invasion, and induce tumor vessel formation. The function of HGF is mediated by c-Met. c-Met is one of proto-oncogene, belonging to transmembrane protein. Many tissues and cells such as hepatocyte, spleen, kidney, hematopoietic cell, hepatoma, gastric cancer, colon carcinoma, bronchogenic carcinoma, thyroid carcinoma can express c-Met. c-Met mRNA concentration is very low and even can't be detected in normal tissues, but its' mRNA concentration is very high in corresponding cancer cell. Therefore, inhibiting the reciprocity between HGF and c-Met is a promising strategy that inhibit tumor production and induce tumor cell apoptosis. Many researchers try to inhibit c-Met expression by antisense oligonucleotides and ribozyme, which have low transduction efficiency and transient working time. RNA interference (RNAi) technique emergence provides a new way to inhibit gene expression. Proposed by Fire et al in 1998, RNAi is the post transcription gene silence induced by dsRNA, which can silence gene specifically and result in gene functional incapacitation or reduction. RNAi has specificity, persistence and sensitivity, and its' applications in genome medicine, gene therapy, gene function study, mechanisms of gene expression regulation study are more and more extensive.The purpose of this experiment is to inhibit HGF receptor, c-Met, expression by RNAi technique mediated by viral vector, inhibit tumor cell proliferation and induce tumor cell apoptosis, and explore new way for tumor gene therapy.First, human U6 promotor and the fragment including c-Met reverse complement target sequence were obtained by PCR. HU6shmet was constructed into adenovirus vector and adeno-associated virus vector. Then, the recombination adenovirus vectors and adeno-associated virus vectors were transduced into SK-BR-3 cells. Basic control was bland cells. Transduction efficiency was monitored by GFP. Non-specificity inhibition control was unrelated short hairpin RNA structure. β-actin was inner reference standard. c-Met mRNA level was assayed by slit hybridization. c-Met protein level was assayed by Western Blot. At last, SK-BR-3 proliferation activity was assayed by MTT.rAdUshmet1 titer is 108.25 TCID50/ml, and rAdUshmet2 is 108 TCID50/ml. While rAAVUshmet1 and rAAVUshmet2 titer are 4×1012vg/ml. c-Met expression level of SK-BR-3 cells are higher than that of HepG2 and QGY7703. Transduction efficiency into SK-BR-3 cells of rAd is 100%, while that of rAAV is 20%.Compared with rAdUsicon, c-Met mRNA relative level of SK-BR-3 cells transduced by rAdUshmet1 is decreased 35.0% (p<0.005), while rAdUshmet2 is decreased 48.7% (p<0.005). Compared with bland cells, c-Met mRNA relative level of SK-BR-3 cells transduced by rAdUshmet1 is decreased 30.7% (p<0.05), while rAdUshmet2 is decreased 45.3% (p<0.005).Compared with rAAVUsicon, c-Met mRNA relative level of SK-BR-3 cells transduced by rAAVUshmet1 is decreased 6.4% (p<0.05), while rAAVUshmet2 is decreased 7.0% (p>.05). Compared with bland cells, c-Met mRNA relative level of SK-BR-3 cells transduced by rAAVUshmet1 is decreased 8.5% (p<0.05), while rAAVUshmet2 is decreased 9.1% (p<0.05).Compared with rAdUsicon, c-Met protein relative level of SK-BR-3 cells transduced by rAdUshmet1 is decreased 9.7% (p<0.05), and rAdUshmet2 is 32.0% (p<0.005). Compared with blank cells, c-Met protein relative level of SK-BR-3 cells transduced by rAdUshmet1 is decreased 24.2% (p<0.005), while rAdUshmet2 is 42.9% (p<0.005).Compared with blank cells, proliferation inhibition rate of SK-BR-3 cells tra...
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