Enhancement of Apo2L/TRAIL signaling pathway receptors by the activation of Klotho gene with CRISPR/Cas9 in Caco-2 colon cancer cells.

Human Klotho gene has many known functions such as anti-aging and anti-tumor, and decreased expression of this gene causes malignant formations in most types of cancer, including colon cancer. Interacting with TRAIL death receptors (DR4 and DR5) induces an apoptotic effect in cancer treatments by reducing the proliferation of cancer cells. The present study aimed to investigate downstream effect of overexpression of Klotho gene, which is known to have an antitumor effect on resistant human colon cancer cells, by examining its action on TRAIL death and decoy (DcR1 and DcR2) receptors for the first time. For this purpose, upregulation of human Klotho gene was achieved with CRISPR/Cas9-mediated system in resistant human colon cancer Caco-2 cells. To determine the effect of upregulation of Klotho gene on cancer cells evaluations with flow cytometry, WST-8, qRT-PCR, ELISA, and immunohistochemical analysis were performed. Then, Klotho gene was knocked out and its apoptotic effect was tested to find out whether it is due to overexpression of Klotho gene or not. Our results indicate that overexpression of Klotho gene in Caco-2 cells via CRISPR/Cas9-sensitized TRAIL death receptor DR4 suppresses the proliferation of cells by leading to apoptosis. Thus, this study conducted on apoptosis-resistant colon cancer cells may bring new insights about the role of Klotho gene in colon cancer.