Our preclinical work indicates that anlotinib acts as a novel inhibitor of VEGFR2 and MET that blocks tumorigenesis in osteosarcoma, which could be translated into future clinical trials.
In rare tumour types we observed, amongst others, a predicted overexpression rate of 55% of samples for CD22 and 55% for ENPP3 in adrenocortical carcinomas, 81% for CD74 and 81% for FGFR3 in osteosarcomas, and 95% for c-MET in uveal melanomas.
Our data assessed specific miRNA profiling deregulation in OS clinical samples and suggest that the expression of miR-1 and miR-133b may control cell proliferation and cell cycle through MET protein expression modulation.
Overexpression of MET, obtained by lentiviral vector-mediated gene transfer, resulted in the conversion of primary human osteoblasts into osteosarcoma cells, displaying the transformed phenotype in vitro and the distinguishing features of human osteosarcomas in vivo.
We analyzed the effect of the MET receptor activation in five human osteosarcoma cell lines evaluating the levels of HGF-dependent activation of MAPK and PKB/AKT as biochemical readouts of mitogenic and invasive responses, respectively.
We have previously found that bone sarcomas express high levels of Met/HGF receptor while in some cases the ligand HGF is co-expressed with the receptor, activating an autocrine loop.
The finding of Met/HGF receptor overexpression in all of the osteosarcomas suggests a role for the met proto-oncogene in the pathogenesis of this tumor.
These data suggest that activation of the Met/HGF receptor by a paracrine or an autocrine mechanism might play a role in the particularly aggressive behaviour of osteosarcomas.