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Oncogene. 2017 Nov 9;36(45):6262-6271. doi: 10.1038/onc.2017.222. Epub 2017 Jul 10.

Impact of histone demethylase KDM3A-dependent AP-1 transactivity on hepatotumorigenesis induced by PI3K activation.

Author information

1
Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
2
Cellular Memory Laboratory, RIKEN Advanced Science Institute, Wako-shi, Saitama, Japan.
3
Division of Metabolic Medicine, Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Meguro-ku, Tokyo, Japan.
4
Department of Enzyme Chemistry, Institute for Enzyme Research, Tokushima University, Tokushima-shi, Tokushima, Japan.
5
Genome Science Division, Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Meguro-ku, Tokyo, Japan.

Abstract

Epigenetic gene regulation linked to oncogenic pathways is an important focus of cancer research. KDM3A, a histone H3 lysine 9 (H3K9) demethylase, is known to have a pro-tumorigenic function. Here, we showed that KDM3A contributes to liver tumor formation through the phosphatidylinositol 3-kinase (PI3K) pathway, which is often activated in hepatocellular carcinoma. Loss of Kdm3a attenuated tumor formation in Pik3ca transgenic (Tg) mouse livers. Transcriptome analysis of pre-cancerous liver tissues revealed that the expression of activator protein 1 (AP-1) target genes was induced by PI3K activation, but blunted upon Kdm3a ablation. Particularly, the expression of Cd44, a liver cancer stem marker, was regulated by AP-1 in a Kdm3a-dependent manner. We identified Cd44-positive hepatocytes with epithelial-mesenchymal transition-related expression profiles in the Pik3ca Tg liver and confirmed their in vivo tumorigenic capacity. Notably, the number and tumor-initiating capacity of Cd44-positive hepatocytes were governed by Kdm3a. As a mechanism in Kdm3a-dependent AP-1 transcription, Kdm3a recruited c-Jun to the AP-1 binding sites of Cd44, Mmp7 and Pdgfrb without affecting c-Jun expression. Moreover, Brg1, a component of the SWI/SNF chromatin remodeling complex, interacted with c-Jun in a Kdm3a-dependent manner and was bound to the AP-1 binding site of these genes. Finally, KDM3A and c-JUN were co-expressed in 33% of human premalignant lesions with PI3K activation. Our data suggest a critical role for KDM3A in the PI3K/AP-1 oncogenic axis and propose a novel strategy for inhibition of KDM3A against liver tumor development under PI3K pathway activation.

PMID:
28692045
DOI:
10.1038/onc.2017.222
[Indexed for MEDLINE]

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