Brain imaging In the companion diffusion tensor MRI study to assess normal whit

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 Brain imaging In the companion diffusion tensor MRI study to assess normal whit Empty Brain imaging In the companion diffusion tensor MRI study to assess normal whit

Post  jy9202 on Thu Jan 02, 2014 5:01 am

The phosphatidylinositol 3 kinase Akt mam malian target of rapamycin pathway controls tumor cell proliferation, growth, and survival after DNA damage, Activation of this pathway is frequent in many cancers and can occur through diverse mechan isms such as amplification of the epidermal growth fac tor receptor ATP-competitive JAK 阻害剤 gene, mutations of the Ras oncogene, PI3K mutations and loss of phosphatase and tensin homologue deleted in chromosome 10, This pathway consists of EGFR Ras PI3K Akt and is a prime target for inhibition in the context of radio therapy, We and others have previously shown that inhibition of the EGFR Ras PI3K Akt pathway can increase susceptibility to radiation induced tumor killing, Inhibition of Ras, PI3 kinase and Akt reduce tumor clonogenic survival after radiation at clinically relevant doses, A phase III randomized clinical trial evaluated the addition of cetuximab, an EGFR inhibitor, to radiotherapy and demonstrated improved overall survival in the combined modality arm over radiation alone, The kinase mTOR consists of TORC1 and TORC2, two functionally distinct multiprotein complexes, TORC1 includes mTOR and raptor, TORC2 is composed of mTOR and rictor and regulates the activity of Akt, mTOR inhi bitors have radiosensitising potential in tumor and vas cular cells, Inhibition of TORC1 activity alone can result in TORC2 mediated feedback phosphoryla tion of Akt on Ser473, The paradoxical feedback activation of the PI3K Akt pathway may compromise the efficacy of TORC1 inhibitors and provide the ratio nale for generating dual inhibitors.



Preclinical studies have demonstrated antitumor activity for the PI3K mTOR inhibitor NVP BEZ235 in a variety of models especially those with PI3K mutation or K Ras mutation, Here, we examined whether the PI3K mTOR inhibi tors BEZ235 and NVP BGT226 could sensitise tumor cells with EGFR overexpression or Ras mutation LDE225 価格 to radiation. We investigaLY2157299 臨床試験 ted two inhibitors to get a bet ter insight of the efficacy of each compound and test whether comparable results will be obtained. Both dual PI3K mTOR inhibitors are issued from the same chemi cal space, BGT226 displays more prolonged effects on target in cells, likely due the slow kinetics on target, Addition ally, we studied how PI3K mTOR inhibition can modify the response of endothelial cells after IR.

A substantial body of evidence has demonstrated that the PI3K mTOR pathway is involved in angiogenesis and functions down stream of vascular endothelial growth factor to promote endothelial cell survival, We therefore tested the impact of one the inhibitors, BEZ235, on VEGF mediated Akt signaling, survival and in vitro angiogenesis in irradiated tumor and endothelial cells. BGT226 and BEZ235 inhibit PI3K and mTOR activity and reduce AKT and S 6 phosphorylation We initially aimed to confirm inhibition of PI3K and mTOR by these novel compounds and to establish their minimum inhibitory concentrations.

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