Activation of the PI3K/Akt/mTOR/p70S6K1 Signaling Cascade in the Mononuclear Cells of Peripheral Blood: Association with Insulin and Insulin-Like Growth Factor Levels in the Blood of Patients with Cancer and Diabetes

Abstract

The aim of the present work was to determine the insulin and insulin-like growth factor (IGF-1) content in blood in association with the activity of the end components of the PI3K/Akt/mTORC1/p70S6K signaling cascade in the peripheral blood mononuclear cells (PBMC) of patients with type 2 diabetes (T2D) and cancer. Insulin and IGF-1 levels in blood and Akt (Ser473) and p70S6K (Thr389) phosphorylation in PBMC were studied by enzyme immunoassay in the following groups: 1—control group—age-representative group of healthy individuals; 2—T2D patients; 3—cancer patients; 4—patients with both cancer and T2D. It has been demonstrated that the insulin level is significantly increased in the blood of T2D patients and the patients with T2D and cancer (group 4). The IGF-1 level is substantially increased in cancer patients. Akt and p70S6K phosphorylation is enhanced in cancer patients, which indicates the activation of these protein kinases. The mechanisms linking Akt and p70S6K activation in PBMC and insulin and IGF-1 levels in the blood of patients with cancer and diabetes are discussed.