CAMK2G Promotes Neuronal Differentiation and Inhibits Migration in Neuroblastoma.

ABSTRACT

PURPOSE: Neuroblastoma (NB) originates from differentiation arrest of sympathoadrenal progenitors in the neural crest. It is necessary to reveal the differentiation mechanism of NB. Previously, we reported that Purkinje cell protein 4 (PCP4) is a well-differentiated marker of NB tissues. Herein, we explored the underlying mechanism of PCP4 induced differentiation in order to find better treatment options for patients. METHODS: We screened the interacting proteins of PCP4 by co-immunoprecipitation (Co-IP) and liquid chromatography-mass spectrometry (LC-MS/MS). Then we investigated the relevance between expression of calmodulin-dependent protein kinase II gamma (CAMK2G) and clinical features using R2 platform. We also explored the function of CAMK2G in NB cells by knockdown and RNA sequencing. RESULTS: Here, we verified the binding of PCP4 and calmodulin (CaM) by Co-IP and identified a target kinase of CaM, CAMK2G, by LC-MS/MS. PCP4 overexpression activates the autophosphorylation of CAMK2G. Patients with high CAMK2G expression had better survival while low CAMK2G was associated with unfavorable clinical features including MYCN-amplification, unfavorable histology, progression and high INSS stage. CAMK2G knockdown inhibited neurite outgrowth and down-regulated neuronal differentiation markers (NF-H, MAP2), yet promoted migration, invasion and proliferation. Gene Ontology (GO) analysis showed that knockdown of CAMK2G downregulated the expression of neuronal differentiation-related genes. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that knockdown of CAMK2G upregulated the expression of migration-related genes. CONCLUSION: These findings indicate that CAMK2G activated by PCP4/CaM complex promotes differentiation and inhibits migration in NB cells. LEVEL OF EVIDENCE Not applicable.