William Roman Torreguitart, Shannalee R. Martinez, Noemi Santiago Martinez, Brenda Rodriguez Ruiz, Geoffrey Rodriguez, Eric Rosa, Ana Maria Escalona, Ralph Krumhansl, Kosj Yamoah, Jong Y. Park, Julie Dutil, and Carlos J. Diaz Osterman

Puerto Rico Urology Group, Mayagüez, PR, Ponce Research Institute, Ponce Health Sciences University, Ponce, PR, Moffitt Cancer Center, Tampa, FL, University of Puerto Rico Comprehensive Cancer Center, San Juan, PR, University of Puerto Rico Medical Sciences Campus, San Juan, PR

Introduction/Background. Prostate cancer (PCa) is the leading cause of cancer death among men in Puerto Rico. Recent evidence indicates that Puerto Rican men are at higher risk of dying from PCa than other Hispanic subgroups in the United States. The reasons for this disparity are unknown, but several variables are likely contributors, including socioeconomic factors, diet/lifestyle, and tumor biology. Tumor metabolism may serve as a useful indicator of these interacting factors, especially when analyzed in the context of cardiometabolic risk factors (CMRF). Furthermore, as tumor-immune crosstalk is modulated by tumor metabolism, metabolomic profiling may also provide insights into the tumor evasion mechanisms of PCa.

Hypothesis/Goal of Study. The current study is designed to integrate metabolomic profiles with advanced high-dimension imaging of tumor tissues from Puerto Rican men. These studies will provide global untargeted metabolite levels that may be correlated with clinical comorbidities/CMRF and tumor immune composition. In preparation for this project, we analyzed a subset of our study cohort for correlations between tumor aggressiveness and co-existing CMRF.

Methods and Results. Clinical data was abstracted from medical health records of n=40 consenting participants receiving treatment in Puerto Rico. Chi-square tests were used to assess correlations between CMRF with PCa aggressiveness stratified by CAPRA-S. Of the CMRF analyzed, hypertension and overweight were associated with intermediate-risk compared to low-risk PCa (p=0.0308, 0.0060, respectively). Hypertension was also associated with high-risk compared to low-risk PCa (p=0.0027), as was pre-diabetes (p=0.0001). These associations held when intermediate and high risk were analyzed as a group compared to low-risk PCa; however, an association with hyperlipidemia also became significant (p=0.0309).

Discussion/Conclusions. In the future, these studies will be expanded to include our larger cohort of cases aimed at evaluating the prognostic and predictive value of an integrative multi-omics approach to risk stratification for Puerto Rican men with PCa.

Grant/Funding Support. PR-INBRE DRPP Full Project, grant number 2P20GM103475-19.

Abstract Embargoed

Ronald W. Bucher, Alex Lee, Michelle Aguilar-Gaspar, Alexandra Gebbia, Monica Lopez, Dylan Lewis, Clara Whitehead, Valentine Savioz, Emi Umemoto, Farah Tabassum, Brayden Fults, Lauren Patterson, and Daniel B. Stovall
Department of Biology, Winthrop University, Rock Hill, SC

Introduction: Glioblastoma multiforme (GBM) is the most common and lethal cancer of the central nervous system, and its malignancy is often driven by abnormal gene expression profiles. Polycomb (Pc) proteins are important regulators of gene expression that mediate normal cell differentiation and identity. Multiple Pc proteins are de-regulated in cancers and play roles in chemo- and radio-resistance in GBM, specifically. The Pc protein Ring1- and YY1-binding protein (RYBP) exerts antitumor effects in multiple cancers and is frequently silenced in GBM. However its molecular functions in GBM, and the mechanisms leading to is aberrant silencing in GBM, remain unknown.

Hypothesis: We hypothesized that forced expression of RYBP in GBM cell lines would decrease cell viability, migration, and invasion, and that multiple epigenetic mechanisms contribute to RYBP downregulation in GBM.

Methods and Results: We transduced U-118 or T98 GBM cell lines with lentivirus expressing RYBP or a GFP control and established stable cell lines. RYBP-expressing U-118MG and T-98G cells showed decreased migration in wound-healing assays and decreased invasion in Matrigel-coated transwell assays when compared to control cells. Moreover, Western blots revealed changes in epithelial-to-mesenchymal transition (EMT) and apoptotic protein markers among RYBP-expressing cells that suggest induction of a less invasive and less viable phenotype. Additionally, transient transfection of synthetic inhibitors against specific miRNAs restored RYBP protein levels, and both RYBP mRNA and protein levels increased in response to treatment with a DNA methyltransferase inhibitor, 5-aza-2’-deoxycytidine, and G-quadruplex-stabilizing ligands PhenDC3 and TmPyP4.

Conclusion: Overall, our findings suggest RYBP exerts tumor suppressive effects in GBM and that DNA methylation and G-quadruplex resolution contribute to its transcriptional silencing, while miRNAs suppress RYBP protein synthesis. Further delineation of the pathways leading to RYBP silencing and the networks activated by restored RYBP levels may illuminate cellular programs that can be therapeutically exploited in GBM treatment.

Grant/Funding Support: SC INBRE DRP 5P20GM103499-21

Sita Withers1, Cambri Moeller1, Andrew Lewin1, Brent Stanfield2, Ellen Sparger3, Joseph Francis4, Konstantin Kousoulas2, and Emmanuelle Ruiz2

1Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, 2Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, 3School of Veterinary Medicine, University of California, Davis, CA, 4Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA

Introduction/Background. Naturally occurring cancers in pet dogs are heterogenous and immunoedited, and therefore represent a comparative model that bridges mouse and human studies. The limiting factor in the utility of using pet dogs for comparative immunotherapy studies has historically been our inability to detail canine immune responses due to a relative lack of species-specific reagents. Furthermore, given the well-established effects of aging on immune competency and the prevalence of cancer amongst older individuals, it is also important to detail aging-related immunosenescence in this model species.

Hypothesis/Goal of Study. Our goals were to 1) explore the immune microenvironment in paired primary and metastatic canine osteosarcomas, and 2) detail immunosenescence in pet dogs.

Methods and Results. Preliminarily, we have analyzed transcriptional differences between five pairs of primary and metastatic canine osteosarcomas using the nCounter Canine IO panel and the Nanostring platform. These data reveal distinct expression patterns and immune infiltrate profiles between tumor locations. We also utilized single-cell RNA sequencing (scRNAseq) to profile peripheral blood lymphocytes in two young (2 and 3 years) and two aged dogs (12 and 13 years). We observed different proportions of immune cell types in aged dogs compared to young dogs. Key findings included an enrichment of Th17 cells in old dogs, and enrichment of naïve CD4+ and CD8+ T cells, and central memory CD8+ T cells in young dogs.

Discussion/Conclusions. Immune transcript differences between paired primary and metastatic canine osteosarcoma samples suggest an altered immune microenvironment between tumor locations. scRNAseq revealed evidence of immunosenescence in dogs that mirrors that observed in human aging.

Citation/Acknowledgements. This work was supported by an Institutional Development Award (IDeA) from the National Institute of General Medical Sciences of the National Institutes of Health under award number 1P20 GM135000-01A.