Dr. Huang’s research interests focus on the investigation of epigenetic regulation of gene expression in breast cancer. There is a growing body of evidence to suggest that changes in the activity of chromatin-modifying enzymes contribute to the uncontrolled cell proliferation and tumorigenesis. Importantly, epigenetic changes, unlike mutations or loss of chromosomes, are reversible that provides a rational mechanism for applying small molecule drugs as personalized therapeutics to target these changes in cancer. Our main research objective is to define in depth the mechanisms and biological consequences of functional interplay between chromatin-modifying enzymes in breast cancer development. We are also interested in identifying novel, small molecule reagents that act as selective inhibitors of important chromatin-modifying enzymes to target more specifically the small regions of chromatin and the subset of genes that are associated with most prominent alterations in the breast cancer genome. Our recent work demonstrated that activities of histone lysine-specific demethylase 1 (LSD1) and histone deacetylases (HDACs) are functionally linked in breast cancer, especially in triple negative breast cancer (TNBC). LSD1 inhibitor in combination with HDAC inhibitor displays superior synergy in blocking growth and metastasis of TNBC cells. We are investigating the precise mechanisms underlying orchestrated LSD1 and HDAC crosstalk in breast cancer and determining how the dysregulated interaction of histone-modifying enzymes leads to aberrant gene silencing and aggressive phenotype of TNBC. We are also studying if targeting LSD1/HDAC crosstalk by novel inhibitors are more efficacious in hindering TNBC growth than current strategies and thus represent a novel targeted therapy for this devastating disease.
Another focus of the lab is to determine the role of polyamine biosynthesis pathway in mediating the activity of estrogen receptor signaling in breast cancer. Since the growth of ER positive breast cancer largely relies on the action of estrogen, antagonizing ER or its ligands is one of the most important strategies for breast cancer treatment and prevention. Our recent study demonstrated that inhibition of a key polyamine biosynthesis enzyme, ornithine decarboxylase (ODC), diminishes ERa expression that leads to the loss of expression or function of several important ERa target or partner genes including PR, NF-kB and cyclin D1. Loss of ODC disrupts the binding of Sp1 and its newly identified co-factors (Pokemon, PARP-1, myc, etc) to ERa minimal promoter element. Clinically, patients that initially respond to anti-estrogen endocrine therapy will gradually develop resistance. This constitutes a major clinical challenge in breast cancer therapy and prevention. Therefore, development of more effective estrogen receptor modulators is necessary for improving the therapeutic efficacy of breast cancer. We are investigating how ODC mediates the expression and activity of ERa and elucidating the potential role of ODC in endocrine resistance development in breast cancer.