EZH2 Lysine Methylation of p38 MAPK Signals Deadly Metastatic Triple-Negative Breast Cancer
Abstract
Triple-negative (estrogen, progesterone, and HER2-neu negative) invasive breast carcinomas (TNBC) comprise approximately 10% of all breast cancers but are responsible for a disproportionate number of deaths. Although it develops in all races, African-American women have a higher incidence of TNBCs compared to white women. The Kleer laboratory was the first to discover that EZH2 is an independent prognostic biomarker and promotes growth and invasion of TNBC in vivo and in vitro. The basis of this Breakthrough application is our recent discovery that EZH2, which is known to methylate histones, is able to methylate p38 MAPK protein, which promotes TNBC metastasis. Specifically, we found that once activated, p38 phosphorylates EZH2 at T367, inducing pEZH2 cytoplasmic expression and activation of vinculin at sites of focal adhesions, to promote TNBC migration, invasion, and metastasis. If our novel findings are proven in human breast cancer samples, we will shift the current paradigms on EZH2 function in breast cancer, will provide a new biomarker of aggressiveness for TNBC, and lead to new ways to approach targeted therapy in TNBC, based on blocking EZH2?p38 protein-protein interaction without affecting the effect of EZH2 on normal cells. We propose the breakthrough hypothesis that in TNBC, EZH2 methylates and activates p38, leading to rapid metastasis. We further hypothesize that blocking the binding of EZH2 to p38 will be a new approach to target TNBC and that detection of pEZH2 (T367), p-p38, and p-vinculin (Y100) proteins in tissue samples may identify aggressive and metastatic TNBC. To test the hypothesis, we propose three aims. In Aim 1, we will elucidate the contribution of EZH2 methylation of p38 to TNBC growth, migration, invasion, and metastasis. We will use cell lines and primary TNBC cells derived from patients? fresh tumors of different races. In Aim 2, we will investigate in detail the binding of EZH2 with p38 and pinpoint the specific binding sites. Dr. Zaneta Nikolovska-Coleska will provide complementary expertise. She is an accomplished chemical biologist and expert on protein-protein interactions and on the discovery and development of small molecules for treatment of cancer. Drs. Kleer and Nikolovska-Coleska have already established collaboration and published studies together. In Aim 3, we will characterize 600 invasive carcinomas from white, African, and African-American women, which includes a cohort of 200 patients from Ghana. We will evaluate the pathology and expression of pEZH2, pp38, and p-vinculin proteins to determine if there are racial differences, associations with age of diagnosis, and with patient survival. Our proposal will address the following overarching challenges: (1) How to distinguish deadly form non-deadly breast cancers by developing new tissue based biomarkers of metastasis before metastasis develop. (2) Identify what drives breast cancer metastasis and how to stop it by discovering a completely new mechanism of action of EZH2 in TNBC, which involves methylation of p38 leading to its activation and induction of TNBC metastasis. (3) Revolutionize treatment regimens, by discovery of a new mechanism driving metastasis in TNBC and design ways to inhibit by blocking EZH2-p38 binding. We will also decrease racial disparities in breast cancer. Our goals are attainable within the next 3 years because all of the tissues are in place, the reagents and methodology are available in our laboratories, and we have expertise in the experiments proposed. Our breakthrough proposal has the potential to profoundly improve management of breast cancer patients because: (1) It will alert clinicians which TNBC tumors have high ability to metastasize at the time of initial biopsy, thus allowing for more effective treatment strategies. (2) It will uncover a new mechanism driving aggressive TNBC tumors, which may be the basis of new small molecules that inhibit the lethal interac
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 05, 2019
- Source ID
- W81XWH1910094
Entities
People
- Zaneta Nikolovska-coleska
Organizations
- United States Army
- University of Michigan