Involvement of Box2 in the regulation of Chka expression in Neuro-2a cells and in human tumor cells.

HOVANYECZ, P.*, CHAZARRETA-CIFRE, L*., DOMIZI, P., BARRERA, M., AND BANCHIO, C.

Congreso; SAIB; 2016

Involvement of Box2 in the regulation of Chka expression in Neuro-2a cells and in human tumor cells.Hovanyecz, P.*, Chazarreta-Cifre, L*., Domizi, P., Barrera, M., and Banchio, C. E-mail: hovanyecz@ibr-conicet.gov.ar and chazarreta@ibr-conicet,gov.arInst Biología Molecular y Celular de Rosario-CONICET & Fac Cs Bioq y Farm- UNR, Rosario, ArgentinaCholine kinase α (CKα) is the first enzyme of the phosphatidylcholine-biosynthetic pathway (Kennedy pathway). We demonstrated that CKα levels increase during retinoic acid (RA)-induced neuronal differentiation and overexpression of this enzyme was also observed in certain types of human tumors. There are two motives in the Chka gene promoter, named Box1 and Box2, which are involved in its transcriptional regulation. Box2 is essential for maintaining low level of expression under proliferating condition, and mutation or its deletion causes induction of Chka expression, thus this region negatively regulates transcription. In this study, we showed that histone demethylase KDM2B interacts with the Box2 both in vitro and in vivo by EMSA and ChIP assays. To get insight in the mechanism of CKα overexpression in human tumors, we searched for mutations in the sequence of the Box2 that could impair KDM2B binding and/or regulation. This analysis was performed by DNA sequencing on samples obtained from different biopsies and tumor cell lines. Likewise, we examined CKα and KDM2B levels by Western Blot and qRT-PCR. To conclude, this study contributes to elucidate the mechanism by which CKα is regulated in different scenarios like RA-induced neuronal differentiation and in tumor cells regulating its aggressiveness.