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The double stranded RNA binding protein Adad1 (adenosine deaminase domain containing 1) is a member of theadenosinedeaminaseacting onRNAs (Adar) protein family with germ cell-specific expression. In mice, Adad1 is necessary for sperm differentiation, however its function outside of mammals has not been investigated. Here, through an N-ethyl-N-nitrosourea (ENU) based forward genetic screen, we identified anadad1mutant zebrafish line that develop as sterile males. Further histological examination revealed complete lack of germ cells in adult mutant fish, however germ cells populated the gonad, proliferated, and entered meiosis in larval and juvenile fish. Although meiosis was initiated inadad1mutant testes, the spermatocytes failed to progress beyond the zygotene stage. Thus, Adad1 is essential for meiosis and germline maintenance in zebrafish. We tested if spermatogonial stem cells were affected using a label retaining cell (LRC) assay and found that the mutant testes had fewer LRCs compared to wild-type siblings, suggesting that failure to maintain the spermatogonial stem cells resulted in germ cell loss by adulthood. To identify potential molecular processes regulated by Adad1, we sequenced bulk mRNA from mutants and wild-type testes and found mis-regulation of genes involved in RNA stability and modification, pointing to a potential broader role in post-transcriptional regulation. Our findings suggest that Adad1 is an RNA regulatory protein required for fertility through regulation of spermatogonial stem cell maintenance in zebrafish.Author SummaryInfertility is a serious problem for millions of couples who wish to have children. Globally more than 10% of couples suffer from infertility due to genetic, epigenetic, and environmental factors. Among these about 50% of cases occur due to genetic factors such as aneuploidy and genetic mutations affecting development of the gametes (i.e. sperm and eggs). Although many genes are known to be involved in germ cell development, genetic causes of infertility are still largely unexplained. Therefore, it is imperative to investigate genes involved in reproductive processes. In this study, we report that theadad1gene is essential for germ cell maintenance and fertility in zebrafish. Our analysis of zebrafishadad1mutants demonstrates that it is required for maintenance of the germline stem cells and for completion of meiosis. This is in contrast to mouseAdad1, which functions later in gamete development to regulate differentiation of haploid sperm. Our work on zebrafishadad1has uncovered previously unknown roles ofadad1function in germline stem cell maintenance.

High fatty acid intake is thought to increase cancer risk. This relationship remains poorly explored in African-descent populations. We examined 24 circulating fatty acids in 2,934 men, including 1,431 prostate cancer cases and 1,503 population controls from Ghana and African Americans and European Americans from the United States, using CLIA-certified mass spectrometry-based assays. We investigated associations with prostate cancer, lifestyle factors, and the fatty acid desaturase (FADS) genetic locus. Levels of circulating fatty acid varied robustly between the three population groups, particularly trans, omega-3 and omega-6 fatty acids. Yet, trans fatty acids, namely elaidic, palmitelaidic, and linoelaidic acids, whose levels were higher in populations from the United States compared to Ghanaian men, were associated with increased odds of prostate cancer among all men. FADS1/2 germline genetic variants and lifestyle explained some of the variation in fatty acid levels, with the FADS1/2 locus showing population-specific associations, suggesting differences in genetic control.

Diabetes commonly affects cancer patients. In breast cancer, it decreases patient survival. Diabetes also impacts African American women more so than European American women, potentially contributing to the breast cancer health disparity. In this study, we investigated the influence of diabetes on breast cancer biology in a diverse patient cohort using a three-pronged approach that included analysis of orthotopic human tumor xenografts, patient tumors, and breast cancer cells exposed to diabetes/hyperglycemia-like conditions. We aimed to identify shared phenotypes and molecular signatures by investigating the metabolome, transcriptome, and tumor mutational burden. Diabetes does not enhance cell proliferation but induces mesenchymal and stem cell-like phenotypes linked to increased mobility and odds of metastasis. It also promotes oxyradical formation and both transcriptome and mutational signatures of DNA repair deficiency. Moreover, food- and microbiome-derived metabolites tend to accumulate in breast tumors in presence of diabetes, potentially affecting tumor biology. Breast cancer cells cultured under hyperglycemia-like conditions acquire increased DNA damage and sensitivity to DNA repair inhibitors. Based on these observations, diabetes-associated breast tumors may show an increased drug response to DNA damage repair inhibitors that are cancer therapeutics. Key words: Breast cancer, diabetes, metabolome, transcriptome, metastasis, DNA repair, mutational signature, health disparity Citation Format: Gatikrushna Panigrahi, Julián Candia, Tiffany H. Dorsey, Wei Tang, Yuuki Ohara, Jung S. Byun, Tsion Zewdu Minas, Amy Zhang, Anuoluwapo Ajao, Ashley Cellini, Harris G. Yfantis, Dean Mann, Olga Ioffe, Xin W. Wang, Huaitian Liu, Christopher A. Loffredo, Ana Maria Napoles, Stefan Ambs. Diabetes-associated breast cancer is molecularly distinct and shows DNA repair deficiency [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB174.

Background: Chronic life stress is more prevalent in low socioeconomic status (SES) communities and has been shown to affect DNA methylation and the immune system. Yet, the biological processes that mediate the impact of SES on health to promote the development of chronic diseases like cancer remain poorly understood. Previous studies have shown that individuals from disadvantaged neighborhoods experience a disproportionate amount of both chemical and non-chemical stressors, in addition to epigenetic alterations such as histone modifications and aberrant DNA methylation, compared to those from advantaged neighborhoods. These alternations lead to differential epigenomic profiles between these socioeconomic groups which can be long lasting, even transgenerational. Our study aims to uncover if DNA methylation is linked to neighborhood socioeconomic deprivation and to a biology that causes changes to the immune microenvironment that would promote breast cancer development, progression, and reduced survival. We are specifically interested in this relationship among Black and White women with breast cancer, largely due to the 40% increased mortality that Black women experience compared to White women. Methods: DNA was extracted from 426 fresh frozen breast tissue samples from 173 Black and 116 White women in the NCI-Maryland Breast Cancer Cohort, including 185 tumor samples, 137 paired adjacent normal tissue samples, and 104 normal breast tissue samples collected from reduction mammoplasty. Using zip codes, we geocoded the locations of our study participants and linked these data to Census tract-level socioeconomic deprivation from the 2000 Census using a Neighborhood Deprivation Index (NDI). We conducted a principal component analysis (PCA) to extract a single variable that represented the shared variance across the original 20 deprivation indicators. PCA loadings about 0.25 were retained in our index including % of households in poverty, % of households on public assistance, % of households with no car, % of female headed households with dependent children, % of households earning less than $30,000 per year, and the % of males and females unemployed. Higher NDI values represented greater deprivation and lower NDI values correlated with less deprivation. The NDI was analyzed either on a continuous scale, in quartiles, or was dichotomized into high and low groups based on median cutoffs. DNA methylation data was acquired using the Illumina EPIC 850K array and a differentially methylated probe (DMP) analysis was done between tumor and paired adjacent normal tissue to identify gene regions of hypo- or hyper-methylation stratified by high and low NDI status. Additionally, using a volcano plot investigating fold change differences between NDI high and NDI low methylation beta values, we identified CpG methylation probes significantly associated with high NDI status in the tumor tissue. Finally, we used a methylCIBERSORT deconvolution analysis to estimate immune cell subpopulation differences by tissue type, race, and neighborhood deprivation status. Results: In characterizing NDI by demographic and clinical characteristics in our cohort, we found that Black participants had significantly higher NDI levels compared to White participants (p Significance: To date, little is known about how the epigenome translates neighborhood disadvantage into health disparities. Our findings show evidence of differential methylation expression in tumor and adjacent normal tissue for individuals experiencing high neighborhood deprivation, potentially translating to more adverse breast cancer outcomes for this group. This work gives mechanistic insight into how socioeconomic position may affect cancerous mammary gland biology by altering DNA methylation patterns and immune cell responses. Citation Format: Brittany D. Lord, Emily Rossi, Tiffany H. Dorsey, Catherine Pichardo, William Wooten, Margaret Pichardo, Ruby Hutchison, Maeve Bailey-Whyte, Anuoluwapo Ajao, Stefan Ambs. Investigating biological mediators of social and environmental risk factors on cancer health disparities. [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 NG06.

Background: Breast cancer subtypes are often used as therapeutic and prognostic measures; however, it is unclear whether there is an association between molecular subtypes and site-specific metastasis. Our study aimed to evaluate the relationship between molecular subtypes and developing metastasis in specific sites. Methods: We selected 118 breast cancer patients with immunohistochemistry confirmed molecular subtype diagnosed in 2020 and 2021 at the Department of Surgery, University College Hospital, Ibadan. We classified the molecular subtypes into four categories, HR+/HER2-, HR-/HER2+, HR+/HER2+, and triple negative (HR-/HER2-). The different sites of metastasis of interest were lungs, liver, brain, and bone. We used the chi-square test to determine the proportions and significance of the subtypes based on the different sites assessed. Results: According to our study, 45.50%, 18.20%, and 36.40% of patients presented with lungs, liver, and other (multiple organs and contralateral breast) metastasis respectively. Additionally, HR+/HER2- and TNBC patients developed metastasis at a higher rate and account for a combined 90.10% of all metastases (the site-specific distribution was even between both subtypes). Conclusion: Overall, while there are limitations in our study based on sample size, our data shows that some molecular subtypes are associated with a higher risk of metastasis. Additionally, while not significant in our study, breast cancer subtypes are associated with different metastatic sites.

There is evidence that tumor immunobiology and immunotherapy response may differ between African American and European American prostate cancer patients. Here, we determined if men of African descent harbor a unique systemic immune-oncological signature and measured 82 circulating proteins in almost 3000 Ghanaian, African American, and European American men. Protein signatures for suppression of tumor immunity and chemotaxis were significantly elevated in men of West African ancestry. Importantly, the suppression of tumor immunity protein signature associated with metastatic and lethal prostate cancer, pointing to clinical significance. Moreover, two markers, pleiotrophin and TNFRSF9, predicted poor disease survival specifically among African American men. These findings indicate that immune-oncology marker profiles differ between men of African and European descent. These differences may contribute to the disproportionate burden of lethal prostate cancer in men of African ancestry. The elevated peripheral suppression of tumor immunity may have important implication for guidance of cancer therapy which could particularly benefit African American patients.

OBJECTIVE: Differentiating men who have lethal forms of prostate cancer from those with a more slow-growing disease remains a major challenge in clinical oncology. Risk stratification strategies are particularly needed for men of African descent who disproportionately bear the prostate cancer burden. Methods: Using a high throughput proximal extension assay, we simultaneously measured 82 immune-oncological proteins in the blood of 819 prostate cancer patients at diagnosis of whom 394 were African American (AA) and 425 were European American (EA). These patients were followed up for a median of 8.6 years since their diagnosis during which 57 died of prostate cancer while 202 died of all causes. To identify an immune-oncology protein signature predictive of lethal prostate cancer, we applied a cross-validated, regularized Cox regression model. Included in this model were the 82 immune-oncology proteins and 6 covariates of clinical significance (age, education, BMI, smoking history, aspirin use, and diabetes). Results: We did not identify a robust predictive signature of lethal prostate cancer for EA patients. However, for AA patients a signature primarily driven by tumor necrosis factor receptor superfamily member 9 (TNFRSF9) and pleiotrophin (PTN) (both positively associated with the risk of lethal disease) and regular aspirin use (negatively associated with risk) were the top predictors (P < 0.05) based on two selection criteria: the feature frequency and the weight of the features' contribution to the prediction. These features combined predicted prostate cancer-specific mortality with an accuracy of 83.7% (SE=3.8%). The two proteins alone, TNFRSF9 and PTN, predicted prostate cancer-specific mortality with an accuracy of 78.2% (SE=4.2%). AA prostate cancer patients with high levels (> median) of both TNFRSF9 and PTN in their blood at diagnosis had the worst prostate cancer-specific survival. By 10 years, 33% of cases with high levels of both TNFRSF9 and PTN died of prostate cancer compared to only 5% of cases with low levels of both or either of these proteins. Conclusions: Our study describes novel blood markers of lethal prostate cancer that can be used for risk stratification of AA patients at the time of diagnosis. AA patients with high levels of both TNFRSF9 and PTN in their sera had the highest risk of dying from prostate cancer. These markers may also be applicable to African prostate cancer patients since the blood-based immunome of Ghanaian and AA men are similar, as shown by our data. Citation Format: Tsion Zewdu Minas, Julián Candia, Tiffany H. Dorsey, Francine Baker, Wei Tang, Maeve Kiely, Cheryl J. Smith, Symone V. Jordan, Obadi M. Obadi, Anuoluwapo Ajao, Christopher A. Loffredo, Clayton Yates, Michael B. Cook, Stefan Ambs. Blood levels of TNFRSF9 and PTN predict lethal prostate cancer among African American men [abstract]. In: Proceedings of the AACR Virtual Conference: 14th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2021 Oct 6-8. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr PR-11.