Chemical Tools for Investigating Lysine Demethylases in Chemoresistance of Triple-Negative Breast Cancer

Description

Chemoresistance in cancer therapy presents a significant challenge, often resulting in reduced chemotherapy efficacy and treatment failures. Growing evidence indicates a close association between lysine demethylases (KDMs), especially LSD1, and chemotherapy resistance. However, the contribution of other KDMs to chemotherapy resistance remains largely unexplored. Our proposal aims to develop robust chemical tools to explore the roles of KDMs in biology, particularly in the context of chemoresistance in Triple Negative Breast Cancer (TNBC), the most aggressive form of breast cancer. TNBC lacks targeted therapy options, making conventional chemotherapy the primary treatment avenue. Unfortunately, TNBC patients frequently develop resistance to chemotherapy, adding complexity to treatment strategies. Understanding the functional roles of KDMs in mediating drug resistance in TNBC could pave the way for innovative treatment approaches for this disease. In the initial phase of our proposal, our objective is to develop fluorescent probes capable of detecting the enzymatic activities of different KDM subclasses. Creating fluorescent probes for detecting KDM activity presents a significant challenge due to two main reasons. Firstly, KDMs are enzymes requiring strict substrate specificity. Secondly, very few electrophilic groups can selectively react with lysine residues without interference from endogenous thiols. To address these issues, we will meticulously screen a library of NBD derivatives to identify suitable lysine-reactive building blocks under physiological conditions. Upon identifying appropriate building blocks, we will construct a series of fluorescent probes to detect various KDM isoforms by linking them with long and diverse peptide sequences through click chemistry strategy. These designed probes will be utilized to screen KDM inhibitors in a high-throughput manner. Furthermore, we will develop cell-permeable fluorescent probes to monitor the intracellular activity of KDM4A--an enzyme overexpressed in various cancer cells. Our ultimate goal is to create dual-function probes capable of both detecting enzymatic activity and conducting proteomic studies of KDMs in TNBC. These probes will enable us to track changes in intracellular KDM activity in drug-resistant TNBC cell lines. More importantly, employing chemical proteomic strategy, we will pinpoint specific KDMs associated with chemotherapy resistance in TNBC. Identifying these specific KDMs linked to chemoresistance may reveal potential drug targets for combating TNBC. Targeting these enzymes with specific inhibitors holds the potential to sensitize cancer cells to chemotherapy and improve patient outcomes in the battle against TNBC. Through the proposed research, we seek to shed light on the roles of KDMs in chemotherapy resistance and provide new avenues for cancer therapy.