Development of Substrate-Selective Probes for Affinity Pulldown of Histone Demethylases
ACS CHEMICAL BIOLOGY
Authors: Marholz, Laura J.; Chang, Le; Old, William M.; Wang, Xiang
Abstract
JmjC-domain containing histone demethylases (JHDMs) play critical roles in many key cellular processes and have been implicated in multiple disease conditions. Each enzyme within this family is known to have a strict substrate scope, specifically the position of the lysine within the histone and its degree of methylation. While much progress has been made in determining the substrates of each enzyme, new methods with which to systematically profile each histone mark are greatly needed. Novel chemical tools have the potential to fill this role and, furthermore, can be used as probes to answer fundamental questions about these enzymes and serve as potential therapeutic leads. In this work, we first investigated three small-molecule probes differing in the degree of methylation state and their differential bindings to JHDM1A (an H3K36me1/2 demethylase) using a fluorescence polarization-based competition assay. We then applied this specificity toward the methylation state and combined it with specificity toward lysine position in the design and synthesis of a peptidic probe targeting H3K36me2 JHDMs. The probe is further functionalized with a benzophenone cross-linking moiety and a biotin for affinity purification. Results showed binding of the peptidic probe to JHDM1A and specific enrichment of this protein in the presence of its native histone substrates. Affinity purification pulldown experiments from nuclear lysate coupled with mass spectrometry revealed the capability of the probe to pull out and enrich JHDMs along with other epigenetic proteins and transcriptional regulators.
Lysine-specific demethylase 2A expression is associated with cell growth and cyclin D1 expression in colorectal adenocarcinoma
INTERNATIONAL JOURNAL OF BIOLOGICAL MARKERS
Authors: Cao, Lin-Lin; Du, Changzheng; Liu, Hangqi; Pei, Lin; Qin, Li; Jia, Mei; Wang, Hui
Abstract
Objective: Lysine-specific demethylase 2A (KDM2A), a specific H3K36me1/2 demethylase, has been reported to be closely associated with several types of cancer. In this study, we aimed to investigate the expression and function of KDM2A in colorectal adenocarcinoma. Methods: A total of 215 colorectal adenocarcinoma specimens were collected, and then subjected to immunohistochemistry assay to evaluate the expression levels of KDM2A, cyclin D1 and other proteins in colorectal adenocarcinoma tissues. Real-time polymerase chain reaction, Western blot, and other molecular biology methods were used to explore the role of KDM2A in colorectal adenocarcinoma cells. Results: In this study, we report that the expression level of KDM2A is high in colorectal adenocarcinoma tissues, and this high expression promotes the proliferation and colony formation of colorectal adenocarcinoma cells, as demonstrated by KDM2A knockdown experiments. In addition, the expression of KDM2A is closely associated with cyclin D1 expression in colorectal adenocarcinoma tissues and cell lines. Conclusions: Our study reveals a novel role for high-expressed KDM2A in colorectal adenocarcinoma cell growth, and that the expression of KDM2A is associated with that of cyclin D1 in colorectal adenocarcinoma.