Overall, c-met protein staining was noted in 36 of 43 (84%) primary prostate cancer samples versus 2 of 11 (18%) benign prostate hyperplasia samples (p < 0.0001) and in 4 of 4 (100%) lymph node metastases, 23 of 23 (100%) bone marrow metastases and 1 of 3 (33%) other metastatic sites.
Our data unequivocally demonstrates the autocrine dependency of HGF/SF-Met-induced transformation and metastasis in this system and supports the theory that the inappropriate expression of HGF/SF and Met proteins could play a role in the development and spread of human tumors.
It is concluded that the metastatic potential of the MET oncogene relies on the properties of its multifunctional docking site, and that a single point mutation affecting signal transduction can dissociate neoplastic transformation from metastasis.
We assessed the effect of human HGF/SF on the dissemination of the B-lymphoma cells and found that administration of 5 microg HGF/SF to mice, injected (i.v.) with c-MET-positive lymphoma cells, significantly (P = 0.018) increased the number of metastases in lung, liver and lymph nodes.
These data indicate that cells expressing mutant MET undergo clonal expansion during HNSCC progression and suggest that MET might be one of the long sought oncogenes controlling progression of primary cancers to metastasis.
HGF/SF is a multifunctional cytokine that enhances the metastatic behaviour of tumour cells in vitro by stimulation of the c-met receptor tyrosine kinase and has been implicated in the development of tumour metastasis in vivo.
Real-time quantitative RT-PCR was used to measure MET gene-specific mRNA in normal tissues, primary tumors and lymphatic metastases and showed a 2-8-fold increased expression in tumor cells which metastasize.
These results suggest that the amplification and overexpression of c-met gene do not play a different role in the progression and metastasis of EBV-positive and EBV-negative gastric carcinomas.
The presence of c-MET mRNA was correlated with T stage (P = 0.025), lymph node metastasis (P = 0.036), distant metastasis (P = 0.031), and stage of the stomach cancer (P = 0.023).
The expression of p53, beta-hCG, c-Met, and uMAGE in primary tumors was significantly higher in the presence of nodal micrometastases vs no metastases (P =.03).
Hepatocyte growth factor (HGF) is a stromal-derived cytokine that plays a crucial role in invasion and metastasis of tumor cells through the interaction with HGF receptor, c-Met, which is frequently overexpressed in pancreatic cancer.
The receptor tyrosine kinase (RTK) c-MET has been implicated in various solid tumors, including SCLC, and is involved in mediating tumorigenesis, cell motility, scattering, invasion and metastasis.
Increased expression of the hepatocyte growth factor (HGF) receptor (c-met) and urokinase type plasminogen (uPA) correlated with the development and metastasis of cancers.
Aberrant signalling through the hepatocyte growth factor/scatter factor receptor Met has been implicated in various aspects of the development of human cancer including the promotion of tumour invasion, angiogenesis and metastasis.
Inhibition of various solid tumors growth and metastasis by SU5416 may be partially attributed to blocking activation of the hepatocyte growth factor receptor.
Recent work indicates that activation of the MET oncogene, which drives invasion and metastasis in cancer, can promote a cancer-associated thrombohemorrhagic syndrome that is mediated by transcriptional up-regulation of the procoagulation factors plasminogen activator inhibitor type-1 and cyclooxygenase-2.
Although MET activation has primarily been linked with tumor cell migration and invasiveness, the amplified wild-type MET in these cells is constitutively activated, and its continued signaling is required for cell survival.
Recent findings indicate that the MET tyrosine-kinase receptor is a sensor of adverse microenvironmental conditions (such as hypoxia) and drives cell invasion and metastasis through the transcriptional activation of a set of genes that control blood coagulation.
Subsequently, the disseminated mesenchymal tumour cells must undergo a reverse transition (mesenchymal-epithelial transition, MET) at the site of metastases, as most metastases recapitulate the pathology of their corresponding primary tumours.
Inhibition of the HGF-Met receptor pathway and tumor angiogenesis by NK4 gene expression has potential therapeutic value toward inhibition of invasion, growth, and metastasis of colon cancer.