CKS1B promotes cell proliferation and invasion by activating STAT3/PD-L1 and phosphorylation of Akt signaling in papillary thyroid carcinoma.

OBJECTIVE: To investigate role of GKS1B and its relationship between STAT3/PD-L1 and p-Akt in papillary thyroid carcinoma (PTC). METHODS: Expression of GKS1B and PD-L1 was determined in PTC cell lines. GKS1B was overexpressed or knocked down by transfection with overexpression plasmids or si-CKS1B. STAT3 inhibitor WP1066 was used to suppress STAT3, and PD-L1 inhibitor Pembrolizumab was used to block PD-L1. Cell viability and invasion were evaluated by MTT and transwell assay, respectively. The expression of STAT3, p-STAT3, Akt, and p-Akt was measured using Western blotting. RESULTS: Both protein levels and mRNA levels of CKS1B and PD-L1 were remarkably up-regulated in PTC cell lines. Knockdown of CKS1B significantly inhibited cell viability and invasion of PTC cells and suppressed STAT3/PD-L1 signaling and Akt phosphorylation, while overexpression of CKS1B led to opposite results. Inhibition of STAT3 or PD-L1 reversed the effects of overexpressed CKS1B on PTC cells. CONCLUSION: The overexpression of CSK1B could promote cell viability and invasion of PTC cells through activation of STAT3/PD-L1 signaling and Akt phosphorylation.