Cancer treatment and cellular stress induced type 2 diabetes mellitus

Abstract

Some cancer treatments induce stress responses that activate protective mechanisms and neuregulin expression. In turn, neuregulin activates ErbB receptors, which are responsible for phosphorylating Insulin Receptor Substrates interfering with insulin activity and causing insulin resistance. The effects of neuregulin have been known to enhance development and survival of various tissues by providing nutrients. The activation of ErbB receptors leads to the activation of P13K, which in turn activates serine kinases responsible for phosphorylating IRS-1 and IRS-2. The serine phosphorylated IRS-1 and IRS-2 negatively modulate insulin signaling through the immediate auto-degradation of the serine phosphorylation of IRS, and dissociation of the IR/IRS complex. Furthermore, serine phosphorylated IRS interferes with downstream effectors such as AKT, which are necessary for modulating the glucose transporter, GLUT4. The purpose of this study is to test the hypothesis that neuregulin induced stress pathways alter glucose transport through similar cascades as insulin signaling. A series of experiments were conducted applying variable doses and combinations of neuregulin and insulin to measure the downstream effect on the level of AKT. These applications demonstrated that insulin and neuregulin activate AKT independent from each other through different complimentary mechanisms.