Identification of Inhibitors of PLU-1, a Histone Demethylase That Promotes Breast Cancer Progression

摘要

PLU-1 is a member of the JARID1 family of Jumonji C histone demethylases and specifically demethylates the diand trimethylated forms of Lys4 in histone H3 (H3K4me2/3). Demethylation of H3K4me2/3 by PLU-1 silences the expression of genes that regulate cell cycle progression in breast cells, promoting invasive cancer. These findings have been corroborated by mouse model studies demonstrating that the activity of PLU-1 is essential to cell proliferation, suggesting that PLU-1 inhibitors hold potential in treating breast cancer. The aim of this project is to express recombinant PLU-1 for use high-throughput screens (HTS) to identify small molecule inhibitors. Toward this goal, multiple constructs encompassing the catalytic domain of PLU-1 have been prepared and tested for soluble expression. The expression tests revealed that the PLU-1 constructs were poorly expressed or insoluble in bacteria. Based on these findings, an alternative approach was adopted wherein we tested the expression of RBP2, an H3K4me2/3-specific demethylase that is highly homologous to PLU-1. These tests demonstrated that most RBP2 constructs were not expressed or insoluble, with the exception of two constructs that showed limited solubility. These findings indicate that additional screening will yield soluble enzymes that can be used in HTS for PLU-1 inhibitors.