Epigenetics in the Pathogenesis of Esophageal Adenocarcinoma

Epigenetic influences, such as DNA methylation, histone acetylation, and up‐regulation/down‐regulation of genes by microRNAs, change the genetic makeup of an individual without affecting DNA base‐pair sequences. Indeed, epigenetic changes play an integral role in the progression from normal esophageal mucosa to Barrett''s esophagus to esophageal adenocarcinoma via dysplasia–metaplasia–neoplasia sequence. Many genes involved in esophageal adenocarcinoma display hypermethylation, leading to their down‐regulation. The classes of these genes include cell cycle control, DNA and growth factor repair, tumor suppressors, antimetastasis, Wnt‐related genes, and proapoptotic genes. Histone acetylation in the pathophysiology of esophageal diseases has not been thoroughly investigated, and its critical role in the development of esophageal adenocarcinoma is less defined. Many microRNAs have been associated with the development of Barrett''s esophagus and esophageal adenocarcinoma. Here, we critically addressed the specific steps most closely influenced by microRNAs in the progression from Barrett''s esophagus to esophageal adenocarcinoma. However, microRNAs can target up to hundreds of genes, making it difficult to correlate directly with a given phenotype of the disease. Esophageal adenocarcinoma progressing from premalignant condition of Barrett''s esophagus carries an extremely poor prognosis. Risk stratification for patients based on their epigenetic profiles may be useful in providing more targeted and directed treatment to patients.     

细胞外组蛋白在炎症反应中的作用机制

背景 组蛋白是真核生物染色质的基本结构蛋白.组织损伤、细胞坏死时被释放到细胞外成为细胞外组蛋白.新近研究发现细胞外组蛋白作为一种危险信号分子或炎性介质,在启动和加重炎症损伤中有重要的作用. 目的 回顾近年来国内外关于细胞外组蛋白的研究,为细胞外组蛋白在创伤后炎症反应中作用机制的研究提供参考. 内容 阐述了组蛋白的结构、生物学功能和细胞外组蛋白的来源,并且从脓毒血症、肝损伤、肺损伤、肾疾病以及抗组蛋白治疗等多方面探讨细胞外组蛋白在创伤后炎症反应的作用和可能机制. 趋向 对其深入研究将为脓毒血症等炎性疾病的治疗提供新的作用靶点和理论依据.     

JARID1B deletion induced apoptosis in Jeko-1 and HL-60 cell lines

Aims: To investigate the involvement of JARID1B histone methyltransferase in the epigenetic change of euchromatic promoter in mantle cell lymphoma (MCL) and acute leukemia. Methods: We retrospectively analyzed the protein of JARID1B and tri-methylated histone H3 lysine 4 (H3K4), histone H3 lysine 9 (H3K9), and cyclin D1 and Ki67 in 30 cases of MCL by immunohistochemistry. JARID1B was depleted by small interfering RNA (siRNA), and cell apoptosis and cell proliferation were detected by flow cytometry and MTT [3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide], histone tri-methylated H3K4 and histone acetylated H3, H4, cyclin D1, Bcl-2, procaspase-3, C-myc were studied by Western blot. Results: We demonstrated that JARID1B was upregulated and histone tri-methylated H3K4 was downregulated in MCL compared to proliferative lymphadenitis, P < 0.05. The expression of histone methylated H3K9 was similar in both. Histone methylation of H3K4 was positively correlated with Ki67 in MCL (Kappa = 0.757, P < 0.05). This study showed that depletion of JARID1B cleavage apoptotic proteins of Bcl-2, procaspase-3, C-myc and resulted in loss cell viability and inducing apoptosis in Jeko-1 and HL-60 cell lines. JARID1B siRNA improved tri-methyl H3K4 and histone acetylated H3 and inhibited cyclin D1, but did not affect histone acetylated H4. Conclusions: This study revealed hyper JARID1B expression and hypo histone H3K4 tri-methylation in MCL. We identify depletion JARID1B as a demethylase which is capable of removing three methyl groups from H3K4 and up-regulating histone acetylation of H3 in both cell lines. Interestingly, depletion of JARID1B inhibits Cyclin D1, which is one of the genes contributes to MCL pathogenesis. JARID1B might be one of therapeutic targets in acute leukemia and MCL.     

Histone Acetylation Level and Histone Acetyltransferase/Deacetylase Activity in Ejaculated Sperm from Normozoospermic Men

Purpose

The aim of this work was to evaluate nuclear histone acetylation level and total histone acetyltransferase (HAT) and deacetylase (HDAC) activity in ejaculated sperm and their relevance to conventional sperm parameters.

Materials and Methods

Thirty-three normozoospermic men were included in this study. Semen samples were processed by swim-up and then immunostained by six acetylation antibodies (H3K9ac, H3K14ac, H4K5ac, H4K8ac, H4K12ac, and H4K16ac). Our preliminary study verified the expression of HAT/HDAC1 in mature human sperm. From vitrified-warmed sperm samples, total HAT/HDAC activity was measured by commercially available kits. Nuclear DNA integrity was also measured by TUNEL assay.

Results

The levels of six acetylation marks were not related with conventional sperm parameters including sperm DNA fragmentation index (DFI) as well as HAT/HDAC activity. However, sperm DFI was positively correlated with HAT activity (r=0.038 after adjustment, p<0.02). HAT activity showed a negative relationship with HDAC activity (r=-0.51, p<0.01). Strict morphology was negatively correlated with acetylation enzyme index (=HAT activity/HDAC activity) (r=-0.53, p<0.01).

Conclusion

Our works demonstrated a significant relationship of acetylation-associated enzyme activity and strict morphology or sperm DFI.     

Involvement of epigenetics and microRNA-29b in the urethane induced inception and establishment of mouse lung tumors

Epigenetic changes are correlated with tumor development showing aberrations in DNA methylation and histone modifications. To find the early changes, we evaluated the epigenetic events from early to late stage of the urethane induced lung tumor development in mouse model and tried to correlate the molecular events with the progression of tumor. We addressed the hypothesis by examining the tumor development, status of DNMTs, HDACs and MBDs, DNA methylation and expression of microRNA-29b during 1 to 36 weeks after urethane exposure that included the period before and after the tumor appearance. Tumors did not appear after 1 or 4 weeks but well defined tumors appeared after 12 weeks and larger tumors appeared at 36 weeks which was prevented by IP6. DNMT1, DNMT3a and DNMT3b were upregulated after urethane exposure at the time of no tumor till the tumor developed and showed its upregulated functional activity. DNMTs are shown to be the targets of microRNA-29b and we showed that microRNA-29b was downregulated in the line of DNMT upregulation. HDAC, the histone modifier, also showed progressive upregulation. Periodic increase in methyl binding proteins, MBD2, supported the expression of gene silencing pathways in terms of the downregulation of tumor suppressor genes, p16 and MLH1. All these molecular alterations were protected in the presence of IP6. Our results showed that the key steps of epigenetics, DNMTs, mir29b, and HDAC1, are altered both before and after the development of tumors.