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MET Tyrosine Kinase Inhibition Enhances the Antitumor Efficacy of an HGF Antibody
Structural highlights
DiseaseMET_HUMAN Note=Activation of MET after rearrangement with the TPR gene produces an oncogenic protein. Note=Defects in MET may be associated with gastric cancer. Defects in MET are a cause of hepatocellular carcinoma (HCC) [MIM:114550.[1] Defects in MET are a cause of renal cell carcinoma papillary (RCCP) [MIM:605074. It is a subtype of renal cell carcinoma tending to show a tubulo-papillary architecture formed by numerous, irregular, finger-like projections of connective tissue. Renal cell carcinoma is a heterogeneous group of sporadic or hereditary carcinoma derived from cells of the proximal renal tubular epithelium. It is subclassified into common renal cell carcinoma (clear cell, non-papillary carcinoma), papillary renal cell carcinoma, chromophobe renal cell carcinoma, collecting duct carcinoma with medullary carcinoma of the kidney, and unclassified renal cell carcinoma.[2] [3] [4] [5] [6] Note=A common allele in the promoter region of the MET shows genetic association with susceptibility to autism in some families. Functional assays indicate a decrease in MET promoter activity and altered binding of specific transcription factor complexes. Note=MET activating mutations may be involved in the development of a highly malignant, metastatic syndrome known as cancer of unknown primary origin (CUP) or primary occult malignancy. Systemic neoplastic spread is generally a late event in cancer progression. However, in some instances, distant dissemination arises at a very early stage, so that metastases reach clinical relevance before primary lesions. Sometimes, the primary lesions cannot be identified in spite of the progresses in the diagnosis of malignancies.[7] FunctionMET_HUMAN Receptor tyrosine kinase that transduces signals from the extracellular matrix into the cytoplasm by binding to hepatocyte growth factor/HGF ligand. Regulates many physiological processes including proliferation, scattering, morphogenesis and survival. Ligand binding at the cell surface induces autophosphorylation of MET on its intracellular domain that provides docking sites for downstream signaling molecules. Following activation by ligand, interacts with the PI3-kinase subunit PIK3R1, PLCG1, SRC, GRB2, STAT3 or the adapter GAB1. Recruitment of these downstream effectors by MET leads to the activation of several signaling cascades including the RAS-ERK, PI3 kinase-AKT, or PLCgamma-PKC. The RAS-ERK activation is associated with the morphogenetic effects while PI3K/AKT coordinates prosurvival effects. During embryonic development, MET signaling plays a role in gastrulation, development and migration of muscles and neuronal precursors, angiogenesis and kidney formation. In adults, participates in wound healing as well as organ regeneration and tissue remodeling. Promotes also differentiation and proliferation of hematopoietic cells.[8] [9] [10] Acts as a receptor for Listeria internalin inlB, mediating entry of the pathogen into cells.[11] [12] [13] Publication Abstract from PubMedReceptor tyrosine kinase therapies have proven to be efficacious in specific cancer patient populations; however, a significant limitation of tyrosine kinase inhibitor (TKI) treatment is the emergence of resistance mechanisms leading to a transient, partial, or complete lack of response. Combination therapies using agents with synergistic activity have potential to improve response and reduce acquired resistance. Chemoreagent or TKI treatment can lead to increased expression of hepatocyte growth factor (HGF) and/or MET, and this effect correlates with increased metastasis and poor prognosis. Despite MET's role in resistance and cancer biology, MET TKI monotherapy has yielded disappointing clinical responses. In this study, we describe the biological activity of a selective, oral MET TKI with slow off-rate and its synergistic antitumor effects when combined with an anti-HGF antibody. We evaluated the combined action of simultaneously neutralizing HGF ligand and inhibiting MET kinase activity in two cancer xenograft models that exhibit autocrine HGF/MET activation. The combination therapy results in additive antitumor activity in KP4 pancreatic tumors and synergistic activity in U-87MG glioblastoma tumors. Pharmacodynamic characterization of biomarkers that correlate with combination synergy reveal that monotherapies induce an increase in the total MET protein, whereas combination therapy significantly reduces total MET protein levels and phosphorylation of 4E-BP1. These results hold promise that dual targeting of HGF and MET by combining extracellular ligand inhibitors with intracellular MET TKIs could be an effective intervention strategy for cancer patients who have acquired resistance that is dependent on total MET protein. Mol Cancer Ther; 16(7); 1269-78. (c)2017 AACR. MET Tyrosine Kinase Inhibition Enhances the Antitumor Efficacy of an HGF Antibody.,Farrell PJ, Matuszkiewicz J, Balakrishna D, Pandya S, Hixon MS, Kamran R, Chu S, Lawson JD, Okada K, Hori A, Mizutani A, Iwata H, de Jong R, Hibner B, Vincent P Mol Cancer Ther. 2017 Jul;16(7):1269-1278. doi: 10.1158/1535-7163.MCT-16-0771., Epub 2017 Mar 24. PMID:28341789[14] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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