The Role of Akt Isoforms in Colorectal Cancer
Technical Report,01 Jul 2013,30 Jun 2015
Tufts Medical Center Inc Boston United States
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Akt activation is found in many cancers, including CRC, and is a marker for CRC initiation and progression. However, since Akt has a central role in cell signaling, targeting the three Akt isoforms concurrently may give rise to unacceptable toxicity. Therefore, selective inhibition of one or more Akt isoforms or their target phosphoproteins may be a more effective treatment strategy for CRC. Though a phosphoproteomics screen, we identified 20 Akt isoform-specific phosphorylation targets as likely to be involved in tumor growth and metastasis. We hypothesized that Akt isoforms and their downstream effectors play essential roles in CRC induction, growth and metastasis. We have found that knockout of Akt1 or Akt2 substantially reduces colorectal tumorigenesis in our genetically engineered mouse model. We also successfully ablated novel downstream targets of Akt in our novel murine colorectal cancer cell lines IWS1, MTSS1 or MIM, FRMD6, SEMA4B, MYH9, and Liprin-1. We found that each phosphorylation target promotes tumorngenesis in vitro. MTSS1 had the greatest effect on in vitro tumorigenesis.