Liu Y, Zheng P, Ji T et al.An epigenetic role for PRL-3 as a regulator of H3K9 methylation in colorectal cancer. Gut 62:571-581
School of Basic Medical Sciences, Southern Medical University, Guangzhou, People's Republic of China.Gut (Impact Factor: 14.66). 02/2012; 62(4). DOI: 10.1136/gutjnl-2011-301059
OBJECTIVE: This study investigated the epigenetic role of PRL-3, a key metastasis gene in colorectal cancer (CRC), as a regulator of histone demethylation and the functions of Jumonji domain-containing protein 1B (JMJD1B) and JMJD2B in the progression of CRC. METHODS: PRL-3-associated proteins were analysed using functional distribution and category enrichment analysis. Western blotting and immunofluorescence were used to detect nuclear PRL-3. The relationship between PRL-3 and JMJD1B or JMJD2B and the roles of JMJD1B, JMJD2B and PRL-3 in histone demethylation were determined after these proteins were knocked down using RNA interference. Case-control studies on JMJD1B and JMJD2B in patients with CRC were performed using immunohistochemical analysis. The in vitro functional effects of JMJD2B and JMJD1B were examined further. RESULTS: JMJD1B and JMJD2B, two histone demethylases, were enriched among PRL-3-associated proteins. Nuclear PRL-3 was observed in CRC cells and clinical samples of CRC. The expression of nuclear PRL-3 was increased in patients with CRC at more advanced Dukes' stages. PRL-3 was involved in the regulation of histone methylation by affecting the activities of JMJD1B and JMJD2B. A low expression of the JMJD1B protein was positively correlated with the lymph node status (p=0.032), Dukes' classification (p=0.008) and TNM staging (p=0.022) of patients with CRC. A high expression of JMJD2B was positively correlated with the lymph node status (p=0.03), Dukes' classification (p=0.036) and tumour invasion (p=0.003) of patients with CRC. A loss-of-function analysis confirmed that JMJD2B promoted the proliferation, colony formation and migration of human CRC cells. CONCLUSION: Our data reveal a new role for PRL-3 as a key regulator of histone demethylation. JMJD1B seems to be a candidate tumour suppressor and JMJD2B seems to be a potential oncoprotein in the development and progression of CRC.
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ABSTRACT: Metastasis-associated phosphatase of regenerating liver-3 (PRL-3) has pleiotropic effects in driving cancer progression, yet the signaling mechanisms of PRL-3 are still not fully understood. Here, we provide evidence for PRL-3-induced hyperactivation of EGFR and its downstream signaling cascades in multiple human cancer cell lines. Mechanistically, PRL-3-induced activation of EGFR was attributed primarily to transcriptional downregulation of protein tyrosine phosphatase 1B (PTP1B), an inhibitory phosphatase for EGFR. Functionally, PRL-3-induced hyperactivation of EGFR correlated with increased cell growth, promigratory characteristics, and tumorigenicity. Moreover, PRL-3 induced cellular addiction to EGFR signaling, as evidenced by the pronounced reversion of these oncogenic attributes upon EGFR-specific inhibition. Of clinical significance, we verified elevated PRL-3 expression as a predictive marker for favorable therapeutic response in a heterogeneous colorectal cancer (CRC) patient cohort treated with the clinically approved anti-EGFR antibody cetuximab. The identification of PRL-3-driven EGFR hyperactivation and consequential addiction to EGFR signaling opens new avenues for inhibiting PRL-3-driven cancer progression. We propose that elevated PRL-3 expression is an important clinical predictive biomarker for favorable anti-EGFR cancer therapy.The Journal of clinical investigation 07/2013; 123(8). DOI:10.1172/JCI66824 · 13.22 Impact Factor
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ABSTRACT: This study investigated the role of histone demethylase Jumonji domain-containing protein 2B (JMJD2B) in promoting epithelial-mesenchymal transition (EMT) and underlying molecular mechanisms in the progression of gastric cancer (GC). The induction of EMT by JMJD2B in GC cells and its underlying mechanisms were examined by a series of assays. In-vivo and in-vitro assays were performed to clarify invasive potential of JMJD2B in GC cells. The expression dynamics of JMJD2B were detected using immunohistochemistry in 101 cases of primary gastric cancer tissues. Inhibition of JMJD2B by specific siRNA suppresses EMT of GC cells, while ectopic expression of JMJD2B induces EMT. Importantly, JMJD2B is physically associated with β-catenin and enhances its nuclear localization and transcriptional activity. JMJD2B together with β-catenin binds to the promoter of the β-catenin target gene vimentin to increase its transcription by inducing H3K9 demethylation locally. JMJD2B inhibition attenuates migration and invasion of GC cells in vitro and metastasis in vivo. The expression of JMJD2B was positively correlated with tumor size (P = 0.017), differentiation status (P = 0.002), tumor invasion (P = 0.045), lymph node metastasis (P = 0.000), distant metastasis (P = 0.024) and TNM stage (P = 0.002) in gastric cancer patients. The data reveals a novel function of JMJD2B in promoting EMT and GC invasion and metastasis, implicating JMJD2B as a potential target for reversing EMT and intervention of the progression of GC.Clinical Cancer Research 09/2013; 19(23). DOI:10.1158/1078-0432.CCR-13-0254 · 8.72 Impact Factor
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ABSTRACT: The Jumonji D2 proteins (JMJD2/KDM4) function to demethylate di- and trimethylated (me2/3) histone 3 lysine 9 (H3K9me2/3) and H3K36me3. Knockout mouse models for Kdm4b and Kdm4d have not resulted in gross abnormalities, while mouse models for Kdm4a and Kdm4c have not been reported. However, the KDM4 subfamily of demethylases are overexpressed in several tumor types. Overexpression of KDM4 proteins alters transcription and chromatin remodeling, driving cellular proliferation, anchorage-independent growth, invasion, and migration. Increased proliferation occurs through KDM4-mediated modification of cell cycle timing, as well as through increased numbers of replication forks. Recent evidence also suggests that KDM4C overexpression contributes to the maintenance of a pluripotent state. Together these data suggest that overexpression of KDM4 proteins induces numerous oncogenic effects.Biochemistry and Cell Biology 12/2013; 91(6):369-77. DOI:10.1139/bcb-2012-0054 · 2.15 Impact Factor
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