IGF-1 activates the P13K/AKT signaling pathway via upregulation of secretory clusterin.

Secretory clusterin (sCLU) is a type of stress-induced, pro-survival glycoprotein elevated in early-stage cancer. It enhances cancer cell survival and is associated with several types of cancer progression. In this study, we measured the PI3K/AKT signaling activity by determining the phosphorylation level of the AKT protein, namely pAKT. A549 human non-small cell lung carcinoma (NSCLC) cells were treated with insulin-like growth factor-1 (IGF-1) for various periods of time. The results showed that IGF-1 activated the PI3K/AKT signaling pathway in the A549 cells in a time-dependent manner. Western blot analysis was performed to determine the expression of sCLU protein in A549 cells treated with IGF-1. IGF-1 elevated the expression of sCLU. To determine whether sCLU is required for the IGF-1 activation of the PI3K/AKT signaling pathway, the A549 cells were treated with IGF-1 and sCLU antisense oligonuleotide (sCLU ASO). sCLU ASO blocked the IGF-1 activation of the PI3K/AKT signaling pathway. These results demonstrate that IGF-1 activates the P13K/AKT signaling pathway via the upregulation of sCLU. The present study implies that this pathway may uncover a new mechanism for cancer progression and reveal new targets for drug development in the treatment of NSCLC.