Insulin Mediated Activation of PI3K/Akt Signalling Pathway Modifies the Proteomic Cargo of Extracellular Vesicles

Proteomics. 2017 Dec;17(23-24). doi: 10.1002/pmic.201600371. Epub 2017 Oct 16.


Epidemiological studies suggest that diabetes and obesity increases the risk of colorectal cancer (CRC) and lowers the patient survival rate. An important attribute in diabetes and obesity is the presence of high levels of growth factors including insulin in blood which can activate the PI3K/Akt signalling pathway. Dysregulation of PI3K/Akt signalling pathway leads to sustained proliferative signals thereby allowing the cells susceptible to cancer. Extracellular vesicles (EVs), secreted nanovesicles of endocytic origin, are implicated in mediating the transfer of oncogenic cargo in the tumour microenvironment. In this study, CRC cells were treated with insulin to activate PI3K/Akt signaling pathway. Insulin treatment significantly increased the number of EVs secreted by CRC cells. Furthermore, pAkt was exclusively packaged in EVs secreted by PI3K/Akt activated cells. Quantitative proteomics analysis confirmed that the protein cargo of EVs are modified upon activation of PI3K/Akt signaling pathway. Bioinformatics analysis highlighted the enrichment of proteins implicated in cell proliferation in EVs secreted by PI3K/Akt activated cells. Furthermore, incubation of EVs secreted by PI3K/Akt activated cells induced proliferation in recipient CRC cells. These findings suggest that EVs can amplify the signal provided by the growth factors in the tumor microenvironment and hence aid in cancer progression.

Keywords: PI3k/Akt signalling; colorectal cancer; extracellular vesicles; intercellular communication.

MeSH terms

  • Cell Proliferation / drug effects
  • Colorectal Neoplasms / drug therapy
  • Colorectal Neoplasms / metabolism*
  • Colorectal Neoplasms / pathology
  • Computational Biology / methods
  • Extracellular Vesicles / drug effects
  • Extracellular Vesicles / metabolism*
  • Gene Expression Regulation / drug effects
  • Humans
  • Hypoglycemic Agents / pharmacology
  • Insulin / pharmacology*
  • Phosphatidylinositol 3-Kinases / metabolism*
  • Proteomics / methods*
  • Proto-Oncogene Proteins c-akt / metabolism*
  • Signal Transduction / drug effects*
  • Tumor Cells, Cultured
  • Tumor Microenvironment / drug effects


  • Hypoglycemic Agents
  • Insulin
  • Phosphatidylinositol 3-Kinases
  • Proto-Oncogene Proteins c-akt