The JMJD2A demethylase regulates apoptosis and proliferation in colon cancer cells

Abstract

JMJD2A is a transcriptional cofactor and enzyme that catalyzes demethylation of histone H3 lysines 9 and 36 and is overexpressed in human tumors, but its role in oncogenesis remains unclear. Here, we show that JMJD2A interacts with the tumor suppressor p53 both in vitro and in HCT116 colon cancer cells. Chromatin immunoprecipitation assays demonstrated that JMJD2A was recruited together with p53 to the promoter of the p21 cell cycle inhibitor upon stimulation with the DNA damaging agent, adriamycin. Downregulation of JMJD2A resulted in increased expression of p21 and of the pro-apoptotic Puma protein, whereas levels of the anti-apoptotic Bcl-2 protein were decreased. Furthermore, JMJD2A knock-down led to reduced HCT116, DLD-1 and HT-29 colon cancer cell proliferation, while overexpression of JMJD2A enhanced HCT116 proliferation in low serum media. Finally, JMJD2A depletion induced apoptosis in HCT116 cells and this effect was less pronounced in the absence of p53. Collectively, these data indicate that JMJD2A is a novel promoter of colon cancer cell proliferation and survival, which mediates its effects in p53-dependent and -independent ways. JMJD2A may therefore be a valid target to sensitize tumor cells to chemotherapy-induced cell death and growth suppression.

Sumoylation of the histone demethylase KDM4A is required for binding to tumor suppressor p53 in HCT116 colon cancer cell lines

“…Flag-KDM4A-WT or Flag-KDM4A (K3R) expression vectors were co-transfected with HA-tagged p53 vector into 293 T cells and immunoprecipitation assays were performed. Consistent with a previous report (Kim et al 2012), Flag-KDM4A strongly interacted with HA-tagged p53. In contrast, mutation of sumoylation sites within KDM4A reduced the interaction between p53 and KDM4A (Figure 4(A)).…”

“…KDM4A-deficient cells exhibit upregulation of p53 target gene (p21, bcl2) expression and lead to reduced colon cancer cell proliferation (Kim et al 2012). Here, we demonstrated that KDM4A was modified by SUMO1, and that this sumoylation was involved in the binding between KDM4A and p53.…”

“…This data may suggest that sumoylation of KDM4A is not involved in regulation of p53 expression in undamaged cells. As KDM4A is recruited to the p21 promoter upon exposure to adriamycin (Kim et al 2012), sumoylation of KDM4A may be required for damage-induced expression of the p53-p21 axis via efficient targeting of the sumoylated KDM4A-p53 complex to the p21 promoter. However these findings cannot rule out the possibility that other post-translational modifications such as ubiquitination, methylation, and acetylation can affect the mutant phenotypes observed in KDM4A-K471A or K3R mutants.…”

“…KDM4A interacts with tumor suppressor protein p53, and KDM4A amino acids 301-703 are responsible for the interaction (Kim et al 2012). Intriguingly, the SUMO-conjugation site, K471, of KDM4A is included within the interaction domain (301-703aa), thereby raising the possibility that sumoylation may influence the interaction between p53 and KDM4A.…”

“…Knockdown of KDM4A increases expression of the tumor suppressor protein p53, leading to apoptosis and reduced proliferation in colon cancer cell lines (Kim et al 2012). One study revealed that SUMO modification plays a crucial role in regulation of the function of heterogeneous nuclear ribonucleoprotein K (hnRNP-K) as a positive regulator of p53 in response to DNA damage (Lee et al 2012).…”