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

Haozhe Xu; Yiming Zhou; Jing Guo; Tao Ling; Yujie Xu; Ting Zhao; Chuanxin Shi; Zhongping Su; Qiang You

doi:10.7555/JBR.37.20230067

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

J Biomed Res. 2023 Sep 10;37(5):340-354. doi: 10.7555/JBR.37.20230067.

Authors

Haozhe Xu¹, Yiming Zhou¹, Jing Guo², Tao Ling¹, Yujie Xu², Ting Zhao³, Chuanxin Shi⁴, Zhongping Su⁵, Qiang You^{1

2}

Affiliations

¹ Department of Geriatrics, Medical Center for Digestive Diseases, the Second Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210011, China.
² Affiliated Cancer Hospital & Institute, Guangzhou Medical University, Guangzhou, Guangdong 510095, China.
³ Department of Medical Oncology, Fudan University Shanghai Cancer Center, Shanghai 200032, China.
⁴ Division of General Surgery, the Second Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210011, China.
⁵ Department of Geriatric Gastroenterology, the First Affiliated Hospital of Nanjing Medical University, Institute of Neuroendocrine Tumor, Nanjing Medical University, Nanjing, Jiangsu 210029, China.

Abstract

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 ²⁺/calmodulin-dependent kinase Ⅱ (CaMKⅡ) reversed the Ca ²⁺-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 FAK and CaMKⅡ were increased in hepatoblastoma. The group with high expression levels of FAK and CaMKⅡ exhibited significantly lower ImmunoScore as well as CD8 ⁺ T and NK cells. The expression of CaMKⅡ was positively correlated with that of PDCD1 and LAG3. Correspondingly, the expression of FAK was negatively correlated with that of TNFSF9, TNFRSF4, and TNFRSF18. Collectively, extracellular calcium accelerates HepG2 cell proliferation and migration via 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.

Keywords: CaMKⅡ; FAK; HepG2; calcium ion; cisplatin resistance; hepatoblastoma.

Grants and funding

This research was funded by the Jiangsu Medical Scientific Research Project of Jiangsu Health Commission (to Q.Y.), the 789 Outstanding Talent Program of SAHNMU (Grant No. 789ZYRC202070102 to Q.Y.), the Guangzhou Key Medical Discipline Construction Project (to Q.Y.), and the National Natural Science Foundation of China (Grant Nos. 81870409 and 81671543 to Q.Y.).