Mutations have also been identi fied while in the c CBL binding site of the juxtamem brane domain and while in the HGF binding region of Aurora B inhibitor the Sema domain.Enhanced protein expression as being a consequence of transcriptional upregulation while in the absence of gene amplification will be the most frequent cause of constitutive c MET activation in human tumors, and continues to be reported in an ever developing number of carcino mas, including thyroid, colorectal, ovarian, pancreatic, lung and breast, to title some.
Hypoxia, triggered by lack of oxygen diffusion on the centre of a developing tumor, is one mechanism that has been demonstrated to activate c MET transcription Aurora B inhibitor in vitro and in vivo. Hypoxia activates the c MET pro moter, via the transcription factor hypoxia induc ible factor 1a, which itself is regulated by the concentration of intracellular oxygen. Although c MET activation via a ligand depen dent autocrine or paracrine loop will be fully dis cussed elsewhere in this supplement, we will touch on it briefly here. HGF is expressed ubiq uitously within the body and has been found to be frequently overexpressed in the reactive stroma of primary tumors. This supports the formation of paracrine positive feedback loops, which in turn can support the dissemination of cancer cells to distant locations.
Oncogene addiction was identified after studies using EGFR tyrosine kinase inhibitors demonstrated that these inhibi tors were efficacious only BI-1356"href="http://www.selleckchem.com/products/linagliptin-bi-1356.html">BI-1356 in a small subset of tumors which exhibited genetic alterations of the receptor itself. Although this c MET addicted phenotype has only recently been described in cultured cells from gastric and non small cell lung carcinomas, it continues to strongly suggest that amplification of the MET gene might be a genetic predictor of therapeutic responsiveness. Oncogene expedience is a tumor specific term that describes the scattering, invasion and sur vival of cancer cells associated with metastatic spreading. In contrast to oncogene addiction, the inappropriate activation of c MET resulting in oncogene expedience is the consequence rather than the cause of the trans formed phenotype.
Thus, activation of c MET is a secondary event in various types of tumor, exac erbating the malignant properties of already transformed cells. In these cases, aberrant Aurora B inhibitor c MET activation occurs through a number of pos sible routes, these include transcriptional upregu lation by other oncogenes, environmental conditions such as hypoxia and agents secreted by reactive stroma such as inflam matory cytokines, proangiogenic factors and HGF itself.
In addition, as MET also acts as an adjuvant prometastatic gene for many neoplasms, targeted therapies against c MET could also be used as a secondary approach to hamper the progression of a much wider spectrum of advanced cancers that rely on c MET activation for metastatic spreading.
Monday, February 18, 2013
Strange But Rather Helpful Sayings About Aurora B inhibitor BI-1356
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