334 - Histone demethylase JMJD3 regulates a copper-containing lysyl oxidase expression in THP-1 cell-derived M2-macrophages

Abstract

Lysyl oxidase (LOX) is a copper-containing amine oxidase that plays a key role in the regulation of extracellular stiffness through the cross-linking of collagen. It has been considered that excess production of LOX participated in the progression of tumor cell metastasis; however, LOX regulation has not been fully elucidated. To determine the molecular mechanisms involved in LOX expression, we used human monocytic THP-1 cell-derived M2-macrophages that participated in the tumor progression. Our results revealed that LOX expression was significantly induced in IL4/IL13-elicited M2-macrophages that was accompanied with the significant induction of CD206 and arginase-1, M2-macrophage markers. On the other hand, LOX induction was not observed in IFNγ/LPS-elicited M1-macrophages. These data are consistent with high LOX expression in metastatic human breast cancer MDA-MB-231 cells. According to the significant involvement of epigenetics in tumor progression, histone modifications including acetylation and methylation in M2-macrophages was investigated. Among histone modifications, the level of histone H3K27me3, an epigenetic marker for transcription suppression, was decreased in M2-macrophages. Based on the previous findings that histone demethylase JMJD3 participated in M2-macrophage differentiation, we investigated the involvement of JMJD3 in LOX induction. As expected, LOX induction was significantly suppressed in the presence of JMJD3 inhibitor, GSK-J4. However, histone deacetylase inhibitor and DNA demethylation reagent did not induce LOX expression, suggesting that JMJD3-mediated histone demethylation could be a key histone modification in LOX expression. Moreover, our ChIP results clearly showed that the level of H3K27me3 within the proximal LOX promoter was decreased. Overall, we have determined that H3K27 methylation is involved in the regulation of LOX expression in THP-1 cell-derived M2-macrophages.