European American Patients Research Articles

Abstract C114: DNA methylation signatures linked to different grades of prostate tumors from African American and European American patients

Abstract Prostate cancer is the second leading cause of cancer-related deaths among men in the United States. Health disparities in men diagnosed with prostate cancer are observed between patients of African and those of European ancestry. To develop biomarkers and elucidate the molecular mechanisms behind prostate tumorigenesis and racial disparities, we collected formalin-fixed paraffin-embedded (FFPE) prostate tissues from African American (AA) and European American (EA) patients. By comparing global DNA methylation profiles among normal samples and different grades of tumor samples from AA and EA, we revealed distinct prostate cancer subgroups with variable DNA methylated regions. We identified thousands of differentially methylated regions between normal and tumor samples, defining hypermethylated and hypomethylated regions. When we examined the frequency of differentially methylated regions among different grades of tumor samples, we found that low-grade tumor samples exhibited fewer hypermethylated regions while high-grade tumors exhibited numerous hypermethylated regions across AA and EA samples. However, we found that a subset of low-grade tumors exhibited many hypomethylated regions similar to high-grade tumors. By clustering prostate tumor samples with the identified differentially methylated regions, we revealed distinct prostate cancer subgroups with unique DNA methylation patterns. By integrating immunohistochemistry data with DNA methylation profiles, we found that the identified subgroups are tightly linked to the overexpression status of ERG, surpassing the ethnicity-related variations. Associating DNA methylation patterns with clinicopathological features and integrating this data with other molecular features, we are characterizing the molecular mechanisms underlying prostate tumorigenesis and health disparities. This study will pave the way to identify novel DNA methylation biomarkers and therapeutic targets linked to different prostate cancer subgroups. Citation Format: Leonardo Gonzalez-Smith, Colton Stensrud, Claire Stevens, Jenaye Mack, Olumide Arigbede, Sarah G Buxbaum, Sara M. Falzarano, Suhn K. Rhie. DNA methylation signatures linked to different grades of prostate tumors from African American and European American patients [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr C114.

Mitochondrial reprogramming by activating OXPHOS via glutamine metabolism in African American patients with bladder cancer.

Bladder cancer (BLCA) mortality is higher in African American (AA) patients compared with European American (EA) patients, but the molecular mechanism underlying race-specific differences are unknown. To address this gap, we conducted comprehensive RNA-Seq, proteomics, and metabolomics analysis of BLCA tumors from AA and EA. Our findings reveal a distinct metabolic phenotype in AA BLCA characterized by elevated mitochondrial oxidative phosphorylation (OXPHOS), particularly through the activation of complex I. The results provide insight into the complex I activation-driven higher OXPHOS activity resulting in glutamine-mediated metabolic rewiring and increased disease progression, which was also confirmed by [U]13C-glutamine tracing. Mechanistic studies further demonstrate that knockdown of NDUFB8, one of the components of complex I in AA BLCA cells, resulted in reduced basal respiration, ATP production, GLS1 expression, and proliferation. Moreover, preclinical studies demonstrate the therapeutic potential of targeting complex I, as evidenced by decreased tumor growth in NDUFB8-depleted AA BLCA tumors. Additionally, genetic and pharmacological inhibition of GLS1 attenuated mitochondrial respiration rates and tumor growth potential in AA BLCA. Taken together, these findings provide insight into BLCA disparity for targeting GLS1-Complex I for future therapy.

A novel role for KIFC1-MYH9 interaction in triple-negative breast cancer aggressiveness and racial disparity

African American (AA) women are twice as likely to develop triple-negative breast cancer (TNBC) as women of European descent. Additionally, AA women with TNBC present a much more aggressive disease course than their European American (EA) counterparts. Thus, there is an unmet clinical need to identify race-specific biomarkers and improve survival outcomes in AA patients with TNBC. The minus-end directed microtubule motor protein kinesin family member C1 (KIFC1) promotes centrosome clustering and chromosomal instability and is often overexpressed in TNBC. Previous findings suggest that KIFC1 plays a role in cell proliferation and migration in TNBC cells from AAs and that the levels of nuclear KIFC1 (nKIFC1) are particularly high in AA patients with TNBC. The nuclear localization of KIFC1 in interphase may underlie its previously unrecognized race-specific association. In this study, we found that in TNBC cells derived from AAs, nKIFC1 interacted with the tumor suppressor myosin heavy chain 9 (MYH9) over EA cells. Treatment of AA TNBC cells with commercial inhibitors of KIFC1 and MYH9 disrupted the interaction between KIFC1 and MYH9. To characterize the racial differences in the KIFC1-MYH9-MYC axis in TNBC, we established homozygous KIFC1 knockout (KO) TNBC cell lines. KIFC1 KO significantly inhibited proliferation, migration, and invasion in AA TNBC cells but not in EA TNBC cells. RNA sequencing analysis showed significant downregulation of genes involved in cell migration, invasion, and metastasis upon KIFC1 KO in TNBC cell lines from AAs compared to those from EAs. These data indicate that mechanistically, the role of nKIFC1 in driving TNBC progression and metastasis is stronger in AA patients than in EA patients, and that KIFC1 may be a critical therapeutic target for AA patients with TNBC.Graphical abstract

Endothelin-1 Correlates with Blood Pressure and Pulse Pressure in Females with Lupus Associated Hypertension

Systemic Lupus Erythematosus (SLE) is a common autoimmune disease that is classified by IgG complex deposition in end organs including the kidney, heart, and vasculature. SLE disproportionally affects women to men (9:1 ratio), with a high prevalence in African American women. Importantly, patients with an SLE diagnosis have common cardiovascular complications including hypertension. Importantly, numerous studies have reported that plasma and urinary endothelin-1 (ET-1) levels are elevated in patients with SLE or hypertension. However, few studies have investigated the role of the synergistic effects of SLE and hypertension on ET-1. Therefore, we hypothesized that women with SLE and hypertension would have elevated plasma ET-1 levels compared to SLE or hypertension alone. To investigate this, we recruited non-SLE non-HTN controls (n=8), non-SLE HTN (n=7), SLE non-HTN (n=5), and SLE-HTN (n=6) female human subjects and analyzed clinical and demographic characteristics, plasma ET-1, c-reactive protein (CRP), soluble vascular adhesion molecule-1 (sVCAM-1), and anti-Smith autoantibodies. We found that plasma ET-1 levels are significantly higher in African American compared to European American patients independent of SLE or blood pressure status (p=0.0182). When plasma ET-1 levels were correlated with age and body mass index (BMI), ET-1 had a positive association with age (r=0.4861;p=0.0118), but no correlation with BMI (r=0.2137;p=0.2945). When subjects we characterized by SLE diagnosis, we found that female subjects with SLE had elevated plasma ET-1 levels compared to non-SLE controls (p=0.0141). Next, we stratified subjects by blood pressure status and found that only SLE-HTN subjects had significantly elevated plasma ET-1 levels compared to non-SLE non-HTN controls (p=0.0005), and a trend for elevated ET-1 levels over SLE non-HTN (p=0.0799). Lastly, we correlated plasma ET-1 levels to offce systolic blood pressure, diastolic blood pressure and calculated pulse pressure. We found that plasma ET-1 positively associated with systolic blood pressure (r=0.5621;p=0.0035) and pulse pressure (r=0.5810;p=0.0023) but not diastolic blood pressure (r=0.3177;p=0.1217). These data demonstrate that plasma ET-1 levels associate with SLE diagnosis and blood pressure status in our cohort of female SLE human subjects. Further investigation of ET signaling should be done in SLE and SLE-HTN human subjects. Veterans Affairs Biomedical Laboratory Research & Development Career Development Award (CDA-2) 1IK2BX005605-01 to J.P.V.B, Medical University of South Carolina College of Medicine Program Project Grant to J.C.O and J.P.V.B., and Medical University of South Carolina Core Centers for Clinical Research Project Award P30AR072582 to M.A.C and J.P.V.B. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Abstract 6116: Rs2363956, a coding variant of ANKLE1, drives triple-negative breast cancer disparity by altering DNA damage response

Abstract African American women have a 42% higher breast cancer mortality rate than European American women and are over twice as likely to develop triple-negative breast cancer (TNBC). We have previously demonstrated that this higher incidence of TNBC is tied to ancestry-related biological determinants of TNBC tumor biology, including possible novel genetic drivers that may result in reduced treatment efficacy. Within the TCGA BRCA cohort, we have previously found that high ANKLE1 gene expression significantly improves survival in European Americans but not in African Americans. This difference may be attributed to the presence of a polymorphic variant of ANKLE1, rs2363956. The minor G allele of rs2363956 leads to a structural alteration in ANKLE1, potentially changing its functionality. Interestingly, among our International Center for the Study of Breast Cancer Subtypes (ICSBCS) patient cohort, we observed that 41-53% of European Americans with TNBC were homozygous for the G allele as compared to only ~14% of African American patients. These observations suggest that the presence of the rs2363956 polymorphic variant may drive differences between European American and African American patients. ANKLE1 is a conserved gene among eukaryotic organisms and has been reported as an endonuclease implicated in DNA damage repair. Among our patient cohort (n=62) we have observed that patients homozygous for the G allele (n=13) are enriched for COSMIC mutational signatures 2 and 13 (P≤.05 and P≤.001, respectively), that denote overactivity of APOBEC deaminases, as compared to patients homozygous for the T allele (n=19). Therefore, the increased mutational burden present in those patients caused by APOBEC overactivity may sensitize those cancer cells to chemotherapeutics or other therapies. Alternatively, the patients homozygous for the T allele may have an increased capacity for DNA damage repair that does not involve APOBEC activity. Using the MDA-MB-231 cell line, which is homozygous for the T allele, we performed an ANKLE1 knockdown with siRNA in order to examine the impact of ANKLE1 loss on DNA damage repair. Upon treatment with 25 μM, 10 μM, and 5 μM of Cisplatin we observe increased γ-H2AX and cell shrinkage in the ANKLE1 knockdowns as compared to cells treated with control siRNA, denoting increased DNA damage and apoptosis. Additionally, after knocking down ANKLE1 we observed decreased proliferation. Based on these observations, ANKLE1 is critical for DNA damage response in TNBC cells and may be implicated in the genomic stability of TNBC. The polymorphic variants observed may impact this function and in part explain why European American patients have improved survival, as compared to African American patients. Citation Format: Yanira Guerra, Rachel Martini, Olivier Elemento, Melissa B. Davis. Rs2363956, a coding variant of ANKLE1, drives triple-negative breast cancer disparity by altering DNA damage response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6116.

Abstract 2146: Race-related differential immunoreactivity of enolase autoantibodies in patients with prostate cancer

Abstract INTRODUCTION AND OBJECTIVE: Enolase-1 (ENO1) and -2 (ENO2) are implicated in tumor metabolic and aggressive functions. Like prostate specific membrane antigen (PSMA), they localize to the tumor cell surface and are potential theranostics targets. ENO autoantibodies were reported by our group in prostate cancer (PCa) patients but their immunoreactivity to ENO1/2 isoforms was not defined. Differential ENO immunoreactivity in docetaxel-resistant (DR) PCa cells between African American (AA) and European American (EA) PCa patients was also reported. Our objective was to investigate the role of ENO isoforms in the race-related differential ENO immunoreactivity of PCa patients. METHODS: PCa patient sera (41 AA, 68 EA) were obtained from Loma Linda University Biospecimen Laboratory. Western blotting (WB) analysis, using patient sera and monoclonal antibodies to ENO1 and ENO2, was done against lysates from docetaxel-sensitive (DS) and DR PCa cell lines and against recombinant (rec) ENO1 and ENO2 to assess ENO isoform expression and detect ENO autoantibodies. Scratch-wound assay was performed to evaluate AA and EA anti-ENO driven inhibition of DR PCa cell migration. Student’s T-test and Chi-squared analyses were performed with p<0.05 deemed significant. RESULTS: ENO1 expression was robust in all assessed DS and DR cell lines. ENO2 was detected in DS cells but was significantly reduced in DR cells. PSMA expression was lost in cells expressing ENO1 and neuroendocrine markers. Anti-ENO EA sera reacted in WB with the expected 50 kD band in both DS and DR PCa cells, but anti-ENO AA sera reacted preferentially with this band in DS cells. Strong immunoreactivity was noted against recENO1 in AA and EA sera (7% vs 28%, p<0.01) and against recENO2 in AA and EA sera (24% vs 35%, p=0.23). EA, but not AA, ENO autoantibodies significantly inhibited DR cell migration, and their pre-absorption with recENO1 diminished this inhibitory effect. CONCLUSIONS: Autoantibodies to ENO1 and ENO2 were identified in EA and AA PCa patient sera. Weaker ENO1 immunoreactivity was seen in sera from AA PCa patients, corresponding with weaker inhibition of DR PCa cell migration compared to EA patient sera. Unlike PSMA and ENO2, ENO1 expression was robust in neuroendocrine-like DR PCa cell lines. Future studies will correlate the presence of ENO autoantibodies with clinicopathologic parameters in a larger patient cohort. Defining mechanisms underlying the race-related differential ENO immunoreactivity may identify novel biological determinants of PCa health disparities and uncover the theranostic potential of tumor surface ENO1. Citation Format: Kai Wen Cheng, Carlos J. Diaz Osterman, Krystal Santiago, Michael Reeves, Diano Lozano, Pedro Ochoa, Alfonso Duran, Saied Mirshahidi, Brian R. Hu, Frankis Almaguel, Carlos A. Casiano. Race-related differential immunoreactivity of enolase autoantibodies in patients with prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2146.

Abstract 6159: Single cell analysis of circulating peripheral blood mononuclear cells in African American men with prostate cancer and their association with lethal disease

Abstract Prostate cancer is a leading cause of cancer-related deaths among men in the United States and affects African American (AA) men more so than other men. We and others previously described a distinct tumor immunobiology in AA prostate cancer patients. Furthermore, we discovered a serum proteome-defined suppression of tumor immunity signature that is prevalent among these patients and associated with lethal prostate cancer. In the current study, we sought to investigate the composition of circulating peripheral blood mononuclear cells (PBMCs) in AA and European American (EA) prostate cancer patients and their association with patient group and lethal prostate cancer. We obtained high-quality RNA-sequencing data for 277336 single cells representing circulating PBMCs from 59 AA and EA men. In the analysis, being an AA patients associated with an increased abundance of exhausted T cells, higher numbers of plasma B cells and CD16+ monocytes. Gene signatures indicative of T cell exhaustion and Treg activity were generally elevated in AA PBMCs while T cell effector function features were decreased. Within the overall cell population, interferon gene signatures were robustly elevated in AA than EA patients. This gene signature pattern that we observed in AA patients also associated with lethal prostate cancer, namely the T cell exhaustion, Treg activity and elevated interferon signaling gene signatures, may contribute to immune dysfunction and immune injury; pointing to potential clinical implications. Lastly, the interferon-induced transmembrane protein (IFITM3), interferon alpha inducible protein (IFI6), cysteine rich protein-1 (CRIP1), and the RAC family small GTPase2 (RAC2) were notably upregulated in AA patient-derived immune cells. In summary, we show that circulating immune cell populations and the associated gene signatures differ between men of African and European descent. Those elevated in AA patients correlated with lethal prostate cancer. Citation Format: Md Shakir Uddin Ahmed, Tiffany Dorsey, Stefan Ambs. Single cell analysis of circulating peripheral blood mononuclear cells in African American men with prostate cancer and their association with lethal disease [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6159.

Global epidemiology of mental disorder in atrial fibrillation between 1998-2021: A systematic review and meta-analysis.

As the burden of mental disorders among patients with atrial fibrillation (AF) increases, researchers are beginning to pay close attention to the risk and prevalence of these comorbidities. Although studies have independently analyzed the risk of comorbidity with depression and anxiety in patients with AF, no study has systematically focused on the global epidemiology of these two mental disorders. To explore the prevalence of depression and anxiety in patients with AF. Five databases were searched from their date of establishment until January 2023. Observational studies reporting the comorbidity of AF with depression and anxiety, were included in this study. Basic information, such as the first author/ publication year, study year, study type, and prevalence of depression and anxiety, were extracted. STATA SE 15.1 was used to analyze the data. Subgroup, meta-regression, and sensitivity analyses were performed to estimate study heterogeneity. After a thorough search, 26 studies were identified and included in this meta-analysis. The prevalence rates of depression and anxiety in adults with AF were 24.3% and 14.5%, respectively. Among adult males with AF, the prevalence was 11.7% and 8.7%, respectively, whereas in females it was 19.8% and 10.1%, respectively. In older adults with AF, the prevalence rates of depression and anxiety were 40.3% and 33.6%, respectively. The highest regional prevalence of depression and anxiety was observed in European (30.2%) and North American (19.8%) patients with AF. In this study, we found that the prevalence of depression and anxiety among patients with AF varies with sex, region, and evaluation scales, suggesting the need for psychological interventions for patients with AF in clinical practice.

Tislelizumab versus chemotherapy as second-line treatment for European and North American patients with advanced or metastatic esophageal squamous cell carcinoma: a subgroup analysis of the randomized phase III RATIONALE-302 study

The phase III RATIONALE-302 study evaluated tislelizumab, an anti-programmed cell death protein 1 antibody, as second-line (2L) treatment for advanced/metastatic esophageal squamous cell carcinoma (ESCC). This prespecified exploratory analysis investigated outcomes in patients from Europe and North America (Europe/North America subgroup). Patients with tumor progression during/after first-line systemic treatment were randomized 1:1 to open-label tislelizumab or investigator's choice of chemotherapy (paclitaxel, docetaxel, or irinotecan). The Europe/North America subgroup comprised 108 patients (tislelizumab: n= 55; chemotherapy: n= 53). Overall survival (OS) was prolonged with tislelizumab versus chemotherapy (median: 11.2 versus 6.3 months), with a hazard ratio (HR) of 0.55 [95% confidence interval (CI) 0.35-0.87]; HR was similar irrespective of programmed death-ligand 1 score [≥10%: 0.47 (95% CI 0.18-1.21); <10%: 0.55 (95% CI 0.30-1.01)]. Median progression-free survival was 2.3 versus 2.7 months with tislelizumab versus chemotherapy [HR: 0.97 (95% CI 0.64-1.47)]. Overall response rate was greater with tislelizumab (20.0%) versus chemotherapy (11.3%), with more durable response (median duration of response: 5.1 versus 2.1 months). Tislelizumab had a favorable safety profile versus chemotherapy, with fewer patients experiencing ≥grade 3 treatment-related adverse events (13.0% versus 51.0%). Those on tislelizumab experienced less deterioration in health-related quality of life, physical functioning, and/or disease- and treatment-related symptoms (i.e. fatigue, pain, and eating problems) as compared to those on chemotherapy, per the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 (QLQ-C30) and QLQ-OES18 scores. As a 2L therapy for advanced/metastatic ESCC, tislelizumab improved OS and had a favorable safety profile as compared to chemotherapy in European/North American ESCC patients in the randomized phase III RATIONALE-302 study.

Abstract C040: Single cell analysis of circulating peripheral blood mononuclear cells in African American men with prostate cancer and their association with lethal disease

Abstract Prostate cancer is a leading cause of cancer-related deaths among men in the United States and affects African American (AA) men more so than other men. We and others previously described a distinct tumor immunobiology in AA prostate cancer patients. Furthermore, we discovered a serum proteome-defined suppression of tumor immunity signature that is prevalent among these patients and associated with lethal prostate cancer. In the current study, we sought to investigate the composition of circulating peripheral blood mononuclear cells (PBMCs) in AA and European American (EA) prostate cancer patients and their association with patient group and lethal prostate cancer. We obtained high-quality RNA-sequencing data for 277642 single cells representing circulating PBMCs from 59 AA and EA men. In the analysis, being an AA patients associated with an increased abundance of exhausted CD8+T cells and higher numbers of macrophages that classified as tumor-associated macrophages, whereas metallothionine-expressing macrophages were decreased in these men. Gene signatures indicative of T cell exhaustion were generally elevated in AA PBMCs while T cell effector function features were decreased. Within the myeloid cell population, cytokine and NFKB signatures were more prevalent in AA than EA patients. This gene signature pattern that we observed in AA patients also associated with lethal prostate cancer, namely the T cell exhaustion and elevated cytokine gene signatures, pointing to potential clinical implications. Lastly, the interferon-induced transmembrane protein (IFITM3), interferon alpha inducible protein (IFI6), cysteine rich protein-1 (CRIP1), and the RAC family small GTPase2 (RAC2) were notably upregulated in AA patient-derived immune cells. In summary, we show that circulating immune cell populations and the associated gene signatures differ between men of African and European descent. Those elevated in AA patients correlated with lethal prostate cancer. Citation Format: Md Shakir U. Ahmed, Tiffany Dorsey, Stefan Ambs. Single cell analysis of circulating peripheral blood mononuclear cells in African American men with prostate cancer and their association with lethal disease [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr C040.

Abstract C050: Allele-specific expression analysis identifies novel dysregulated genes in high-risk prostate tumors from African-American men

Abstract African-American (AA) patients are twice as likely to die from prostate cancer (PCa) compared to European American (EA) patients. Racism, socioeconomic status, access to healthcare, and tumor biology have been attributed to this mortality gap. Tumor biology has not been fully characterized in AA patients, particularly the landscape of gene-regulatory alterations and how they may contribute to tumor aggressiveness. We use allele specific expression (ASE) analysis, which detects genes showing imbalanced expression of alleles often due to altered gene regulation on one allele, to comprehensively identify dysregulated genes in high-risk PCa tumors from AA patients. We develop a framework for identifying candidate cancer genes by integrating ASE data, clinical data, and epigenetics. Our approach identifies genes that recurrently undergo ASE across AA patient tumors. Further, we describe genes that more frequently undergo ASE in AA patient tumors compared to EA patient tumors, some of which are implicated in hormone therapy resistance, aggressive disease, and worse disease-free survival. Our work demonstrates the potential for ASE to uncover dysregulated genes that may not have been identified through RNAseq alone. Ultimately, this work increases our understanding of the effects of regulatory alterations in tumors and how they may contribute to disparities in PCa. Citation Format: Margaret Tsui, Kevin Hu, Hanbing Song, Franklin W. Huang. Allele-specific expression analysis identifies novel dysregulated genes in high-risk prostate tumors from African-American men [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr C050.

Abstract B101: Obesity mediates altered triple-negative breast cancer tumor biology in African American women independent of ancestry

Abstract African American (AA) breast cancer (BC) is associated with a higher incidence of aggressive BC phenotypes at younger age, higher grade of tumor as compared to BCs of age-matched patients of European American (EA). For AA women, there is a higher frequency of the more aggressive TNBC subtype and of the PAM50-molecular basal subtype. AA tumors are enriched for inflammatory and immune pathways, implicating inherited susceptibility associated with African ancestry. Obesity induces a state of low-grade inflammation. AA women tend to be more obese than EA and have elevated a inflammatory markers, including CRP, IL6, and IL1. Since inflammation related to obesity is a reflection of dysfunctional adipocyte biology, we used dataset GSE88837 to perform in silico analysis of gene expression changes in visceral adipose tissue for AAs and EAs. AA adipose tissue is more inflamed than EAs at the same level of obesity (BMI&amp;gt;30). There was a high expression of secreted mediators causing systemic inflammation, including heat shock protein 60 (HSPD1), CXCL1, S100A9, and SPP1. VEGFA, S100A9, and SPP, tumor-promoting angiogenic mediators, were higher in obese AAs than EAs. These data indicate that obesity enhances inflammation in visceral adipose tissue of AAs. We performed in silico analysis of dataset GSE78958, of 400 BC patients annotated for race, BMI, and hormone receptor expression. We analyzed BC patients for differential gene expression, PAM50 subtype, tumor stage and grade, based on race and BMI. AA women have a higher BMI (48.9%) than EA women (32.3%) and a higher percentage of poorly differentiated tumors (51.1%) than EAs (40.6%). AA women with BMI &amp;gt;30, had more basal-like tumors (34.8%) than EA women (19.3%). These analyses confirm that excess adiposity promotes the basal BC phenotype. With BMI &amp;gt;30 as a criterion for obesity, the GSE78958 dataset containing BCs for 96 AA and 200 EA patients was analyzed for differences in gene expression. DEGs showed upregulation of T cell exhaustion marker PTPN22 and LAIR2. The metastasis and proliferation promoting chemokines CXCL1, CCL2, CXC12, CXCR4, and S100A9 were higher in the BCs of obese AAs, than BCs of non-obese AAs. Stemness related genes, STAT1, SOX4, and KLF4, were higher in BCs of obese AAs. CD163-expressing M2 macrophages were higher in BCs of obese AAs. Our group showed that there was a considerable overlap of genes among African and AA cases, but there were some non-overlapping genes indicating that ancestry alone cannot explain the genetic diversity in the tumor phenotype of AA patients. The divergence was largely driven by an upregulated gene signature found among AAs and not seen among African patients. GSE78958 (obesity BC dataset) was mapped for ancestral correlation of altered genes in the AA BC dataset. Ancestry mapping showed an inverse correlation of HSPD1 with ancestry. Obesity upregulated HSPD1 in BCs of AAs as well as in AA adipose tissue and decreased the probability of survival for women of AA ethnicity, suggesting delineation of ancestry-specific and race-specific effects. Citation Format: Deepa Bedi, Rachel Martini, Melissa B. Davis, Clayton Yates. Obesity mediates altered triple-negative breast cancer tumor biology in African American women independent of ancestry [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr B101.

Differences within the Immune Microenvironment May Account for Poorer Outcomes in African American AML Patients Compared to European American Patients with AML

Background: Acute myeloid leukemia (AML) is an aggressive hematological malignancy arising from an immature myeloid progenitor with notoriously poor outcomes. A critical factor responsible for the difficulty in treating this disease evasion of the host immune system by AML. Both the innate and adaptive immune systems have been shown to be dysfunctional in AML with poor type I interferon responses, decreased STING signaling and increased populations of granulocytic and monocytic myeloid derived suppressor cells ultimately leading to poor adaptive response. Studies in solid tumors have demonstrated that variation in immunity contributes to racial disparities in cancer and outcomes. This is felt to be due to variation in geographic ancestry leading to differences in the innate immune genome required due to the need for protection against environmental pathogens. However, no data exists comparing innate and adaptive immunity by race in patients (pts) with AML. Here we sought to characterize the immune microenvironment with treatment outcomes in racially diverse AML pts. Methods: Adults with newly diagnosed AML were identified who had corresponding cryopreserved bone marrow mononuclear cells available within Roswell Park Hematologic Procurement bank. Pts were matched as closely as possible for age, gender, cytogenetic risk per ELN 2017 and molecular profile. Transcriptional differences between African American (AA, n=26) and European American (EA, n=26) AML pts and healthy controls (n=10) were analyzed using transcriptomics data from NanoString Pan Cancer Immune Profile panels. AA and EA AML samples were compared to each other, as well as their race-matched healthy controls. The ‘Limma’ package in R was utilized for differential gene expression analysis. Research was conducted according to the Declaration of Helsinki in accordance with the Institutional Review Board regulated protocol. Results: The median age of the entire cohort (n=52) was 65 years (range: 28-92), with 28 female patients (53.8%) ( Table 1). Within the AA cohort, the majority of pts had intermediate risk cytogenetics per ELN 2017 (n=19; 73.1%, and 6 pts had FLT3 mut (26.1%). Three pts (11.5%) underwent allogeneic stem cell transplant, with a median overall survival (OS) censoring for transplant of 5 months (range; 0.5-68 months) ( Figure 1). Within the EA cohort, most pts had poor risk cytogenetics (n=15; 57.7%). Six pts had FLT3 mut (26.1%), and three pts had TP53 mut (12%). Five pts underwent allogeneic stem cell transplant (19.2%), with a median OS of 16.4 months (range; 0.8-67 months). Sixty-nine significantly (p&amp;lt;0.05, |logFC|&amp;gt;1.5) differentially expressed genes in AA vs. EA pts were identified. Gene set enrichment analysis (GSEA) revealed alterations to Interferon, Jun kinase and STAT signaling pathways in AA pts. In contrast, EA pt samples were enriched for pathways related to amyloid metabolism and other T and B cell immune pathways. Master regulator analysis using LISA highlighted transcriptional dysregulation attributed to PDGB5, CTCF, AR, and NOTCH in AA pts and to GLIS2, SMAD1 and NFE2 in EA pts. Conclusions: As previously reported, we found that a clinically matched cohort of AA AML patients experienced significantly worse OS as compared to EA counterparts. We have identified several significant alterations within the immune microenvironment between cohorts, which may potentially explain this discrepancy in survival in AA patients. These differences could potentially serve as targetable alterations for therapeutic purposes. This work represents the first of its kind evaluating the immune microenvironment by race in AML patients and are awaiting confirmation in a larger cohort.

Genome-wide DNA methylation analysis implicates enrichment of interferon pathway in African American patients with Systemic Lupus Erythematosus and European Americans with lupus nephritis

Systemic Lupus Erythematosus (SLE) is a chronic, multisystem, inflammatory autoimmune disease that disproportionately affects women. Trends in SLE prevalence and clinical course differ by ancestry, with those of African American ancestry presenting with more active, severe and rapidly progressive disease than European Americans. Previous research established altered epigenetic signatures in SLE patients compared to controls. However, the contribution of aberrant DNA methylation (DNAm) to the risk of SLE by ancestry and differences among patients with SLE-associated Lupus Nephritis (LN) has not been well described. We evaluated the DNA methylomes of 87 individuals including 41 SLE patients, with and without LN, and 46 controls enrolled in an ancestry diverse, well-characterized cohort study of established SLE (41 SLE patients [20 SLE-LN+, 21 SLE-LN-] and 46 sex-, race- and age-matched controls; 55% African American, 45% European American). Participants were genotyped using the Infinium Global Diversity Array (GDA), and genetic ancestry was estimated using principal components. Genome-wide DNA methylation was initially measured using the Illumina MethylationEPIC 850K Beadchip array followed by methylation-specific qPCR to validate the methylation status at putative loci. Differentially Methylated Positions (DMP) were identified using a case-control approach adjusted for ancestry. We identified a total of 51 DMPs in CpGs among SLE patients compared to controls. Genes proximal to these CpGs were highly enriched for involvement in type I interferon signaling. DMPs among European American SLE patients with LN were similar to African American SLE patients with and without LN. Our findings were validated using an orthogonal, methyl-specific PCR for three SLE-associated DMPs near or proximal to MX1, USP18, and IFITM1. Our study confirms previous reports that DMPs in CpGs associated with SLE are enriched in type I interferon genes. However, we show that European American SLE patients with LN have similar DNAm patterns to African American SLE patients irrespective of LN, suggesting that aberrant DNAm alters activity of type I interferon pathway leading to more severe disease independent of ancestry.

Microbiome diversity in African American, European American, and Egyptian colorectal cancer patients

PurposeAlthough there is an established role for microbiome dysbiosis in the pathobiology of colorectal cancer (CRC), CRC patients of various race/ethnicities demonstrate distinct clinical behaviors. Thus, we investigated microbiome dysbiosis in Egyptian, African American (AA), and European American (EA) CRC patients. Patients and methodsCRCs and their corresponding normal tissues from Egyptian (n = 17) patients of the Alexandria University Hospital, Egypt, and tissues from AA (n = 18) and EA (n = 19) patients at the University of Alabama at Birmingham were collected. DNA was isolated from frozen tissues, and the microbiome composition was analyzed by 16S rRNA sequencing. Differential microbial abundance, diversity, and metabolic pathways were identified using linear discriminant analysis (LDA) effect size analyses. Additionally, we compared these profiles with our previously published microbiome data derived from Kenyan CRC patients. ResultsDifferential microbiome analysis of CRCs across all racial/ethnic groups showed dysbiosis. There were high abundances of Herbaspirillum and Staphylococcus in CRCs of Egyptians, Leptotrichia in CRCs of AAs, Flexspiria and Streptococcus in CRCs of EAs, and Akkermansia muciniphila and Prevotella nigrescens in CRCs of Kenyans (LDA score >4, adj. p-value <0.05). Functional analyses showed distinct microbial metabolic pathways in CRCs compared to normal tissues within the racial/ethnic groups. Egyptian CRCs, compared to normal tissues, showed lower l-methionine biosynthesis and higher galactose degradation pathways. ConclusionsOur findings showed altered mucosa-associated microbiome profiles of CRCs and their metabolic pathways across racial/ethnic groups. These findings provide a basis for future studies to link racial/ethnic microbiome differences with distinct clinical behaviors in CRC.

Abstract B059: Understanding the role of poly (ADP-ribose) polymerase 1 (PARP-1) activity in prostate cancer

Abstract Prostate cancer (PCa) is the most diagnosed cancer in men in the United States. African American men have two times higher incidence rate and death rate from PCa than European American men. In PCa, the androgen receptor (AR) acts as a pro-oncogenic transcription factor. Androgen deprivation therapy (ADT) and AR antagonists are the current standard of care for advanced PCa. Late stage of disease is recognized as metastatic castrate resistant prostate cancer (mCRPC) due to adaptive resistance to ADT. mCRPC remains universally fatal with no durable therapeutic options. Poly (ADP-ribose) polymerase 1 (PARP-1) has been identified as a driver of cancer cell survival through the recruitment of DNA-damage-repair enzymes and regulation of oncogenic transcription factors, such as AR, in PCa. PARP-1 enzymatic activity is elevated in mCRPC patient tumors as compared to primary tumors. Although increased PARP activity in these tumors has been shown to be a driver of cancer cell survival, the mechanisms and consequences of elevated PARP activity in PCa remains an active research program in our lab, especially regarding PARP-responsive transcriptional networks. PARP inhibitors (PARPi) have been approved for use in mCRPC with alterations in homologous recombination (HR) genes. The experiments below are designed to better understand the mechanisms by which PARP enzymes may transcriptionally regulate and promote pro-tumorigenic functions. Five different PARP inhibitors were analyzed in a CRPC cell line model to assess their relative potencies and develop IC50 values. A cell growth assay using trypan blue exclusion was used to compare the effectiveness of this IC50 value in regular growth conditions as it compares to steroid depleted growth conditions used to mimic ADT. Immunoblot analyses show that there is differential impact on PARP activity (PARylation) in response to the PARPi tested at the respective IC50 concentrations. It will be imperative to better understand how PARP-1 manipulation regulates gene expression. Tissue microarray (TMA) data was analyzed to assess the level of PARP-1, PAR &amp; gH2AX levels in tissue derived from African American versus European American patients. Although not statistically significant, higher PARylation levels were present in African American TMAs compared to European American prostate tumors. It is essential to obtain TMAs representing a more diverse patient demographic to further assess this difference in PARylation levels As well as TMA data, Patient-Derived Explants (PDEs) from patients with different racial backgrounds were assessed for differential impact of PARPi based on race. Collectively, these studies and future studies for this project will further establish the impact of PARP on PCa gene expression programs and provide resources for future studies exploring PARP in PCa. Further, they may help elucidate mechanisms to address PCa racial disparities. Citation Format: Moriah Cunningham, Latese Evans, Salome Tchotorlishvili, Jasibel Vasquez Gonzalez, Candice Bizzaro, Matthew Schiewer. Understanding the role of poly (ADP-ribose) polymerase 1 (PARP-1) activity in prostate cancer [abstract]. In: Proceedings of the AACR Special Conference: Advances in Prostate Cancer Research; 2023 Mar 15-18; Denver, Colorado. Philadelphia (PA): AACR; Cancer Res 2023;83(11 Suppl):Abstract nr B059.

Multiple Correspondence Analysis and HLA-Associations of Organ Involvement in a Large Cohort of African-American and European-American Patients with Sarcoidosis

Sarcoidosis is a systemic granulomatous disease with predominant pulmonary involvement and vast heterogeneity of clinical manifestations and disease outcomes. African American (AA) patients suffer greater morbidity and mortality. Using Multiple Correspondence Analysis, we identified seven clusters of organ involvement in European American (EA; n = 385) patients which were similar to those previously described in a Pan-European (GenPhenReSa) and a Spanish cohort (SARCOGEAS). In contrast, AA (n = 987) had six, less well-defined and overlapping clusters with little similarity to the cluster identified in the EA cohort evaluated at the same U.S. institutions. Association of cluster membership with two-digit HLA-DRB1 alleles demonstrated ancestry-specific patterns of association and replicated known HLA effects.These results further support the notion that genetically influenced immune risk profiles, which differ based on ancestry, play a role in phenotypic heterogeneity. Dissecting such risk profiles will move us closer to personalized medicine for this complex disease.

17β-estradiol and B-cell intrinsic type I interferon amplify toll-like receptor 7 signaling loop in B cells of female lupus prone BXD2 mice

Abstract While systemic lupus erythematosus (SLE) disproportionally affects women versus men, elevation in 17β -estradiol (E2) alone is not sufficient to promote the development of autoantibody producing B cells. The objective of the present study is to determine if B-cell intrinsic mechanisms contribute to the increased TLR7 response to E2 stimulation. We identified that there were elevated circulating levels of E2 in young African American (AA) SLE patients (24–41 yr-old), compared to older AA (42–56 yr-old) and European American SLE patients (24–66 yr-old). Circulating E2 levels positively correlated with the levels of anti-Smith (Sm) and the expression of interferon-beta (IFNβ) in naïve B cells of SLE patients (n=39). Mouse studies were used to determine if E2 stimulates the expression of IFNβ in B cells and if sex plays a role to influence B cell responses to E2. Serum levels of Sm/RNP and RNP autoantibodies positively correlated with the levels of E2 in female lupus prone BXD2 mice post-puberty (12-wk-old) but not pre-puberty (4–6-wk-old). At the post-puberty stage (&amp;gt;12 wk-old), there were significantly elevated levels of anti-DNA and anti-Sm in female BXD2 mice, compared to male mice. This was associated with an increased TLR7-induced expression of IFNβ and CD69 in transitional stage 1 (T1: CD23 −IgM +CD93 +) B cells in female BXD2 mice, compared to male mice. Interestingly, E2 stimulation promoted intracellular levels of IFNβ and TLR7 in T1 B cells from female but not male BXD2 mice. Together, our results suggest that elevation of E2 in combination with an increased B-cell susceptibility to E2 induction of IFNβ may play a role in the increased B cell responses to TLR7 stimulation in individuals predisposed to the development of SLE. This study was supported by grants from VA Merit Review grant (I01BX004049), NIH grants R01-AI-071110, R01 AI134023, and Lupus Research Alliance Distinguished Innovator Award to J.D.M, the LRA Target Identification in Lupus Award to H-C.H., and the P30-AR-048311

Abstract 1904: Somatic copy number alterations and gene expression signatures are associated with aggressive tumor biology in African Americans and European Americans with renal cell carcinoma

Abstract Background: Renal cell carcinoma (RCC) is the deadliest of all urologic cancers in the US. RCC survival is highly dependent on histology. Survival rates range between 55-60% for clear cell RCC (ccRCC) and 80-90% for papillary RCC (pRCC) patients. African Americans (AAs) have lower survival rates when compared to their European American (EA) counterparts for both histologies (ccRCC 67.1 vs 72.6, pRCC 80.5 vs 87.5). RCC survival disparities may be accredited to population differences in tumor biology, such as somatic copy number alteration (SCNA) profiles of tumor suppressor and oncogenes, and differential gene expression signatures with associated cellular pathway dysregulation. SCNAs are the most common structural change in the human genome and ccRCC and pRCC-specific SCNAs have been associated with clinical outcomes. ClearCode34, a 34 gene expression signature, was developed to classify ccRCC tumors into two distinct ccRCC subtypes (ccA and ccB). The ccB subtype is associated with worse survival and features like increased tumor size, grade, and metastasis rates. We hypothesize there are more aggressive tumor biology phenotypes in AA RCC patients compared to their European counterparts. Methods: Comparative genome-wide, chromosomal, and gene SCNA analyses were performed in AA and EA ccRCC and pRCC patients in TCGA using Partek Genomics Suite 7 (1-way ANOVA, P&amp;lt;0.05). Prediction analysis of microarray in R was used to classify ccRCC patients into ccA and ccB subtypes by race based on the ClearCode34 gene expression signature (t-test, P&amp;lt;0.05). Differentially expressed genes (DEGs) between AA and EA patients were identified using Partek Genomics Suite 7 (1-way ANOVA, P&amp;lt;0.05). Gene Set Enrichment Analysis (GSEA) was performed using a pre-ranked gene list (Fold changes &amp;gt;2 or &amp;lt;-2, P&amp;lt;0.01) and two Molecular Signatures Database collections (C6 oncogenic signatures, C7 immunologic signatures). Results: AA-enriched SCNVs were identified on chromosomes 1, 3, 6, 7, and 12 in ccRCC patients, and chromosomes 1, 4, 6, 7, 8, 10, 16 and 20 in pRCC patients. Six cytobands and genes experienced a SCNV across both histologies (1p21.1, 1p21.3, 6p12.1, 6p12.3, 6p21.1, 6q12), BMP5 (on 6p12.1), CD2AP (on 6p12.3), ENPP4 (on 6p21.1), and SLC44A3-AS1 (on 1p21.3). AAs and EAs had significantly different frequencies of ccA (AA 33.9% vs EA 52.2%) and ccB subtypes (AA 66.1% vs EA 47.8%). Unique DEGs were found between AA and EA ccA and ccB patients (131 ccA only, 165 ccB only), which corresponded with up- and down-regulation in kidney cancer with oncogenic KRAS (C6) and various immunologic pathways (C7). Conclusions: Population-specific SCNAs, ccB subtypes, and pathways may help explain differences in RCC tumor biology amongst AA and EA patients. Future Directions: Replicate these findings in the Cooperative Human Tissue Network/Geisinger validation cohort. Citation Format: Samantha Greenberg, Alex Bart, Destiny Ortiz Fernandez, Heinric Williams, Khadijah A. Mitchell. Somatic copy number alterations and gene expression signatures are associated with aggressive tumor biology in African Americans and European Americans with renal cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1904.

Abstract 1937: Racial differences of epigenome in normal breast tissue reveal biological pathways implicated in racial disparities in breast cancer

Abstract Racial disparity in breast cancer is well recognized. Compared to European American (EA) women, African American (AA) women are more often diagnosed with breast cancer at younger ages, have a more advanced or aggressive disease, and have poorer outcomes. Increasing evidence suggests that biological differences between EA and AA women, particularly differences in epigenetic changes of DNA methylation (DNAm), may contribute to the observed cancer disparity. We hypothesize that racial differences in DNAm in normal breast tissue may reflect distinct genomic susceptibility to breast cancer in different racial groups. Therefore, we investigated epigenome-wide differences of DNAm in normal breast tissue between 178 EA and 272 AA women using the Illumina TruSeq Methyl Capture EPIC library and NGS technology. We identified 17,340 differentially methylated CpG loci (DMLs) between EA and AA women, of which 7,744 were hypermethylated in AA women and 9,596 were hypermethylated in EA women. Pathway analyses of genes annotated to these racial DMLs suggested enrichment of biological processes including cell movement, cell motility, and cell migration, features that are likely linked to the aggressiveness and metastatic potentials of tumor cells. We further examined racial differences in DNAm of breast cancer-related candidate genes and GWAS-identified breast cancer risk loci. Approximately 30% of candidate genes were found to have racial differences in DNAm at more than three CpG sites and these candidate genes were enriched for pathways related to response to stimulus and anatomic structure development. Most interestingly, racial DMLs were found to be enriched for breast cancer risk loci that are associated with risk of estrogen-receptor negative (ER-) breast cancer, treatment response to aromatase inhibitor, and breast cancer-specific morality, phenotypes of which we observed differences between EA and AA breast cancer patients. Our results suggest that racial differences in DNAm in normal breast tissue may induce different biological processes that lead to distinct clinical features of breast tumors observed in EA and AA women and provide an epigenetic mechanism underlying the observed racial disparities. Further research is need to validate the findings of this study. Citation Format: Nan Lin, James Castle, Jinpeng Liu, Chunyan He. Racial differences of epigenome in normal breast tissue reveal biological pathways implicated in racial disparities in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1937.