ASH2L, a COMPASS core subunit, is involved in the cell invasion and migration of triple-negative breast cancer cells through the epigenetic control of histone H3 lysine 4 methylation

HDAC5, an early osimertinib-responsive gene, is a novel therapeutic target for the drug resistance in EGFR-mutant lung adenocarcinoma cells

Aberrant epigenetic regulation is closely associated with drug tolerance, an early step in the acquisition of drug resistance. We previously reported that a pioneer transcriptional factor (also called an epigenetic initiator) rapidly induced by osimertinib, a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, plays a pivotal role in promoting the formation of osimertinib-tolerant cells. In this study, to identify novel epigenetic factors associated with osimertinib-tolerance, we performed a comprehensive screening of epigenetic factors whose expression is rapidly induced by osimertinib. Our results revealed that HDAC5, a class IIa histone deacetylase (HDAC), is a prominently induced epigenetic regulator in several EGFR-mutant non-small cell lung cancer (NSCLC) cell lines during the early response to osimertinib. Knockdown of HDAC5 significantly reduced the emergence of osimertinib-resistant cells. Furthermore, treatment with LMK235, a selective HDAC5 inhibitor, significantly increased global histone acetylation and enhanced osimertinib-induced apoptosis. These findings highlight the potential of HDAC5 as a novel therapeutic target to overcome osimertinib-resistance and suggest LMK235 as a promising compound to provide therapeutic benefit to EGFR-mutant NSCLC patients receiving osimertinib treatment.

KMT2C and KMT2D aberrations in breast cancer

KMT2C and KMT2D are histone lysine methyltransferases responsible for the monomethylation of histone 3 lysine 4 (H3K4) residues at gene enhancer sites. KMT2C/D are the most frequently mutated histone methyltransferases (HMTs) in breast cancer, occurring at frequencies of 10-20% collectively. Frequent damaging and truncating somatic mutations indicate a tumour-suppressive role of KMT2C/D in breast oncogenesis. Recent studies using cell lines and mouse models to replicate KMT2C/D loss show that these genes contribute to oestrogen receptor (ER)-driven transcription in ER+ breast cancers through the priming of gene enhancer regions. This review provides an overview of the functions of KMT2C/D and outlines the recent clinical and experimental evidence of the roles of KMT2C and KMT2D in breast cancer development.

maGENEgerZ: An Efficient Artificial Intelligence-Based Framework Can Extract More Expressed Genes and Biological Insights Underlying Breast Cancer Drug Response Mechanism

Understanding breast cancer drug response mechanisms can play a crucial role in improving treatment outcomes and survival rates. Existing bioinformatics-based approaches are far from perfect and do not adopt computational methods based on advanced artificial intelligence concepts. Therefore, we introduce a novel computational framework based on an efficient support vector machine (esvm) working as follows: First, we downloaded and processed three gene expression datasets related to breast cancer responding and non-responding to treatments from the gene expression omnibus (GEO) according to the following GEO accession numbers: GSE130787, GSE140494, and GSE196093. Our method esvm is formulated as a constrained optimization problem in its dual form as a function of λ. We recover the importance of each gene as a function of λ, y, and x. Then, we select p genes out of n, which are provided as input to enrichment analysis tools, Enrichr and Metascape. Compared to existing baseline methods, including deep learning, results demonstrate the superiority and efficiency of esvm, achieving high-performance results and having more expressed genes in well-established breast cancer cell lines, including MD-MB231, MCF7, and HS578T. Moreover, esvm is able to identify (1) various drugs, including clinically approved ones (e.g., tamoxifen and erlotinib); (2) seventy-four unique genes (including tumor suppression genes such as TP53 and BRCA1); and (3) thirty-six unique TFs (including SP1 and RELA). These results have been reported to be linked to breast cancer drug response mechanisms, progression, and metastasizing. Our method is available publicly on the maGENEgerZ web server.