Tip60-dependent acetylation of KDM2B promotes osteosarcoma carcinogenesis

Overexpression of KDM2B is frequently occurred in various human solid tumours, and the high levels of KDM2B are associated with tumourigenesis. However, whether and how its activities might be modulated to facilitate tumour progression is still unclear. Immunoprecipitation and immunoblotting were carried out to detect the acetylation of KDM2B. Nucleosomes and mononucleosomes were prepared and the demethylation activity of KDM2B was detected in these two substrates. The effects of KDM2B acetylation on the transcription of target genes, as well as tumour growth and metastasis were then studied. KDM2B was acetylated in osteosarcoma cancer cell lines (MG-63 and HOS). This modification occurred at lysine 758 and catalysed by Tip60. Acetylation of KDM2B decreased the capacity of KDM2B in binding with nucleosomes. KDM2B acetylation diminished its demethylation activity towards nucleosomal substrates rather than towards bulk histone. Besides, acetylation of KDM2B diminished its ability to bind with the promoters of p21 and puma. Moreover, the promoting effects of KDM2B acetylation on tumour cells' proliferation and metastasis, and in vivo tumour growth were dependent on Tip60. KDM2B is acetylated at lysine 758 by Tip60 in human osteosarcoma cells. Acetylation of KDM2B diminishes its association with nucleosomes, and thus increasing methylation of H3K36 at its target genes as well as enhancing its oncogenic effects.