Elevated extracellular calcium ions accelerate the proliferation and migration of HepG2 cells and decrease cisplatin sensitivity.

Hepatoblastoma is the most frequent liver malignancy in children. HepG2 has been discovered as a hepatoblastoma-derived cell line and tends to form clumps in culture. Intriguingly, we observed that the addition of calcium ions reduced cell clumping and disassociated HepG2 cells. The calcium signal is in connection with a series of processes critical in the tumorigenesis. Here, we demonstrated that extracellular calcium ions induced morphological changes and enhanced the epithelial-mesenchymal transition in HepG2 cells. Mechanistically, calcium ions promoted HepG2 proliferation and migration by up-regulating the phosphorylation levels of focal adhesion kinase (FAK), protein kinase B, and p38 mitogen-activated protein kinase. The inhibitor of FAK or Ca /calmodulin-dependent kinase Ⅱ (CaMKⅡ) reversed the Ca -induced effects on HepG2 cells, including cell proliferation and migration, epithelial-mesenchymal transition protein expression levels, and phosphorylation levels of FAK and protein kinase B. Moreover, calcium ions decreased HepG2 cells' sensitivity to cisplatin. Furthermore, we found that the expression levels of and were increased in hepatoblastoma. The group with high expression levels of and exhibited significantly lower ImmunoScore as well as CD8 T and NK cells. The expression of was positively correlated with that of and . Correspondingly, the expression of was negatively correlated with that of , , and . Collectively, extracellular calcium accelerates HepG2 cell proliferation and migration FAK and CaMKⅡ and enhances cisplatin resistance. FAK and CaMKⅡ shape immune cell infiltration and responses in tumor microenvironments, thereby serving as potential targets for hepatoblastoma.