Research and Contributions to Science

Define the specificity of the human autoantibody response to the DFS70/LEDGFp75

The clinical and biological significance of human antinuclear autoantibodies (ANAs) targeting the dense fine speckled (DFS) nuclear protein DFS70, also known as LEDGFp75, remains elusive. The frequencies of these autoantibodies are very low in ANA-positive autoimmune rheumatic diseases but are relatively elevated in clinical laboratory referrals, diverse inflammatory conditions, and 'apparently' healthy individuals. Dr. Carlos A. Casiano’s group reported previously that DFS70/LEDGFp75 is an autoantigen in prostate cancer (PCa) that closely interacts with another 70kD DFS nuclear protein called MeCP2. I participated in a research project in Dr. Casiano’s laboratory where we investigated if human anti-DFS sera exclusively target DFS70/LEDGFp75 or also recognize its interacting partner MeCP2, using several complementary autoantibody detection platforms and cellular/molecular approaches. The data showed that these antibodies are highly specific for DFS70/LEDGFp75 and do not target MeCP2. This was an important contribution toward establishing the specificity of the anti-DFS ANA response. This work formed the basis for several abstracts that I presented at local and national scientific meetings and a publication. In addition, I was the first author in two comprehensive review papers focused on the DFS70/LEDGFp75 autoantigen-autoantibody system, and co-author in a third review discussing the emergence of alpha-enolase as a cancer-associated autoantigen and therapeutic target in cancer. See the publications below:

Delineate molecular pathways contributing to chemoresistant PCa.

Patients with metastatic castration-resistant prostate cancer (mCRPC) develop resistance to conventional therapies including docetaxel (DTX). Identifying molecular pathways underlying DTX resistance is critical for developing novel combinatorial therapies to prevent or reverse this resistance. Studies in Dr. Casiano’s laboratory identified transcriptomic signatures associated with the acquisition of chemoresistance using RNAseq in DTX-sensitive and -resistant mCRPC cells. We observed that a transcriptomic program associated with epithelial to mesenchymal transition (EMT) and cancer stem cells was upregulated in the DTX-resistant cells. In addition, we demonstrated that glucocorticoid signaling upregulates the DTX resistance-associated oncoproteins LEDGF/p75 and Clusterin in PCa cells and suggested that this effect may be enhanced in African American PCa cells. These additional studies provided an initial framework for understanding the contribution of glucocorticoid signaling to PCa health disparities. I particularly contributed to the phenotype validation of the DTX-resistant mCRPC cells by examining chemoresistance markers via quantitative immunoblotting. These studies served as a foundation for my dissertation research, which focuses on the role of the LEDGF/p75 interactome in PCa chemoresistance. To define this role, I have used several complementary approaches, including human autoantibodies as tools, immunoprecipitation, confocal microscopy, gene silencing, and functional assays in chemoresistant PCa cells. My contributions to the Casiano Lab studies on PCa chemoresistance have allowed me to be an author in several publications. See the publications below:

Characterize molecular pathways and biomarkers contributing to PCa health disparities

African-American (AA) and Hispanic/Latino (H/L) men have higher rates of advanced PCa attributed to a lack of access to early screening, higher prevalence of risk factors such as obesity and diet, and genetic differences. Consequently, there is a critical need to identify potential biomarkers for the future development of targeted therapies to disrupt disease progression. Studies in Dr. Kittles lab suggested that vitamin D decreases some oncogenes' activity and could be important for preventing PCa, especially for AA men. I contributed to the validation, optimization, and characterization of African American-derived cell lines and performed treatments in models of colony formation assays. My contribution to the Kittles lab as a postdoc has allowed me to collaborate and co-author a publication. See the publication below:

Determine the role of insulin-like growth factor (IGF) modulators in the context of metastatic PCa

In PCa, low IGF1 receptor (IGF1R) expression is linked to metastasis in H/L men, and IGF1 variants are associated with risk in AA men. Despite efforts to target IGF1R, toxicity remains an issue, prompting the exploration of alternative candidates. Based on my preliminary studies, one potential candidate is CYR61, a modulator of the IGF1R signaling pathway and downstream known target of the Yes-Associated Protein (YAP1). I reported that endogenous CYR61 expression was upregulated in the metastatic PCa cell lines and demonstrated that recombinant IGF1 induced the expression of CYR61. I also showed that knockdown of cytoplasmic CYR61 abrogated androgen receptor (AR) splice variant, AR-v7, relevant for therapy resistance. Also, knockdown of CYR61 decreased PCa aggressive properties in metastatic cells by decreasing activation of the PI3/AKT signaling pathway, cellular metabolism, prostasphere formation, migration, invasion, and colony formation. I am currently developing this project to as the foundation for my career development and a publication of this work is readily available. A publication for this research and supported by the Burroughs Wellcome Fund (1277523) is under review and highlighted below.