1,25-Dihydroxyvitamin D3 Suppresses Prognostic Survival Biomarkers Associated with Cell Cycle and Actin Organization in a Non-Malignant African American Prostate Cell Line

Vitamin D3 is a steroid hormone that confers anti-tumorigenic properties in prostate cells. Serum vitamin D3 deficiency has been associated with advanced prostate cancer (PCa), particularly affecting African American (AA) men. Therefore, elucidating the pleiotropic effects of vitamin D on signaling pathways, essential to maintaining non-malignancy, may provide additional drug targets to mitigate disparate outcomes for men with PCa, especially AA men. We conducted RNA sequencing on an AA non-malignant prostate cell line, RC-77N/E, comparing untreated cells to those treated with 10 nM of vitamin D3 metabolite, 1α,25(OH)2D3, at 24 h. Differential gene expression analysis revealed 1601 significant genes affected by 1α,25(OH)2D3 treatment. Pathway enrichment analysis predicted 1α,25(OH)2D3- mediated repression of prostate cancer, cell proliferation, actin cytoskeletal, and actin-related signaling pathways (p < 0.05). Prioritizing genes with vitamin D response elements and associating expression levels with overall survival (OS) in The Cancer Genome Atlas Prostate Adenocarcinoma (TCGA PRAD) cohort, we identified ANLN (Anillin) and ECT2 (Epithelial Cell Transforming 2) as potential prognostic PCa biomarkers. Both genes were strongly correlated and significantly downregulated by 1α,25(OH)2D3 treatment, where low expression was statistically associated with better overall survival outcomes in the TCGA PRAD public cohort. Increased ANLN and ECT2 mRNA gene expression was significantly associated with PCa, and Gleason scores using both the TCGA cohort (p < 0.05) and an AA non-malignant/tumor-matched cohort. Our findings suggest 1α,25(OH)2D3 regulation of these biomarkers may be significant for PCa prevention. In addition, 1α,25(OH)2D3 could be used as an adjuvant treatment targeting actin cytoskeleton signaling and actin cytoskeleton-related signaling pathways, particularly among AA men.

Epigenetic Modulation of GPER Expression in Gastric and Colonic Smooth Muscle of Male and Female Non-Obese Diabetic (NOD) Mice: Insights into H3K4me3 and H3K27ac Modifications

Type 1 diabetes (T1D) affects gastrointestinal (GI) motility, favoring gastroparesis, constipation, and fecal incontinence, which are more prevalent in women. The mechanisms are unknown. Given the G-protein-coupled estrogen receptor's (GPER) role in GI motility, we investigated sex-related diabetes-induced epigenetic changes in GPER. We assessed GPER mRNA and protein expression levels using qPCR and Western blot analyses, and quantified the changes in nuclear DNA methyltransferases and histone modifications (H3K4me3, H3Ac, and H3K27Ac) by ELISA kits. Targeted bisulfite and chromatin immunoprecipitation assays were used to evaluate DNA methylation and histone modifications around the GPER promoter by chromatin immunoprecipitation assays in gastric and colonic smooth muscle tissues of male and female control (CTR) and non-obese diabetic (NOD) mice. GPER expression was downregulated in NOD, with sex-dependent variations. In the gastric smooth muscle, not in colonic smooth muscle, downregulation coincided with differences in methylation ratios between regions 1 and 2 of the GPER promoter of NOD. DNA methylation was higher in NOD male colonic smooth muscle than in NOD females. H3K4me3 and H3ac enrichment decreased in NOD gastric smooth muscle. H3K4me3 levels diminished in the colonic smooth muscle of NOD. H3K27ac levels were unaffected, but enrichment decreased in NOD male gastric smooth muscle; however, it increased in the NOD male colonic smooth muscle and decreased in the female NOD colonic smooth muscle. Male NOD colonic smooth muscle exhibited decreased H3K27ac levels, not female, whereas female NOD colonic smooth muscle demonstrated diminished enrichment of H3ac at the GPER promoter, contrary to male NOD. Sex-specific epigenetic mechanisms contribute to T1D-mediated suppression of GPER expression in the GI tract. These insights advance our understanding of T1D complications and suggest promising avenues for targeted therapeutic interventions.

Prognostic and therapeutic potential of senescent stromal fibroblasts in prostate cancer

The stromal component of the tumour microenvironment in primary and metastatic prostate cancer can influence and promote disease progression. Within the prostatic stroma, fibroblasts are one of the most prevalent cell types associated with precancerous and cancerous lesions; they have a vital role in the structural composition, organization and integrity of the extracellular matrix. Fibroblasts within the tumour microenvironment can undergo cellular senescence, which is a stable arrest of cell growth and a phenomenon that is emerging as a recognized hallmark of cancer. Supporting the idea that cellular senescence has a pro-tumorigenic role, a subset of senescent cells exhibits a senescence-associated secretory phenotype (SASP), which, along with increased inflammation, can promote prostate cancer cell growth and survival. These cellular characteristics make targeting senescent cells and/or modulating SASP attractive as a potential preventive or therapeutic option for prostate cancer.

Chromatin Accessibility Landscape of Human Triple-negative Breast Cancer Cell Lines Reveals Variation by Patient Donor Ancestry

African American (AA) women have an excessive risk of developing triple-negative breast cancer (TNBC). We employed Assay for Transposase-Accessible Chromatin using sequencing to characterize differences in chromatin accessibility between nine commonly used TNBC cell lines derived from patients of European and African ancestry. Principal component and chromosome mapping analyses of accessibility peaks with the most variance revealed separation of chromatin profiles by patient group. Motif enrichment and footprinting analyses of disparate open chromatin regions revealed differences in transcription factor activity, identifying 79 with ancestry-associated binding patterns (FDR < 0.01). AA TNBC cell lines exhibited increased accessibility for 62 transcription factors associated with epithelial-to-mesenchymal transition, cancer stemness/chemotherapeutic resistance, proliferation, and aberrant p53 regulation, as well as KAISO, which has been previously linked to aggressive tumor characteristics in AA patients with cancer. Differential Assay for Transposase-Accessible Chromatin signal analysis identified 1,596 genes located within promoters of differentially open chromatin regions in AA-derived TNBC, identifying DNA methyltransferase 1 as the top upregulated gene associated with African ancestry. Pathway analyses with these genes revealed enrichment in several pathways, including hypoxia. Culturing cells under hypoxia showed ancestry-specific stress responses that led to the identification of a core set of AA-associated transcription factors, which included members of the Kruppel-like factor and Sp subfamilies, as well as KAISO, and identified ZDHHC1, a gene previously implicated in immunity and STING activation, as the top upregulated AA-specific gene under hypoxia. Together, these data reveal a differential chromatin landscape in TNBC associated with donor ancestry. The open chromatin structure of AA TNBC may contribute to a more lethal disease.

SIGNIFICANCE

We identify an ancestry-associated open chromatin landscape and related transcription factors that may contribute to aggressive TNBC in AA women. Furthermore, this study advocates for the inclusion of diversely sourced cell lines in experimental in vitro studies to advance health equity at all levels of scientific research.

Metronomic Administration of Topotecan Alone and in Combination with Docetaxel Inhibits Epithelial-mesenchymal Transition in Aggressive Variant Prostate Cancers

Prostate cancer is the second leading cause of noncutaneous cancer-related deaths in American men. Androgen deprivation therapy (ADT), radical prostatectomy, and radiotherapy remain the primary treatment for patients with early-stage prostate cancer (castration-sensitive prostate cancer). Following ADT, many patients ultimately develop metastatic castration-resistant prostate cancer (mCRPC). Standard chemotherapy options for CRPC are docetaxel (DTX) and cabazitaxel, which increase median survival, although the development of resistance is common. Cancer stem-like cells possess mesenchymal phenotypes [epithelial-to-mesenchymal transition (EMT)] and play crucial roles in tumor initiation and progression of mCRPC. We have shown that low-dose continuous administration of topotecan (METRO-TOPO) inhibits prostate cancer growth by interfering with key cancer pathway genes. This study utilized bulk and single-cell or whole-transcriptome analysis [(RNA sequencing (RNA-seq) and single-cell RNA sequencing (scRNA-seq)], and we observed greater expression of several EMT markers, including Vimentin, hyaluronan synthase-3, S100 calcium binding protein A6, TGFB1, CD44, CD55, and CD109 in European American and African American aggressive variant prostate cancer (AVPC) subtypes-mCRPC, neuroendocrine variant (NEPC), and taxane-resistant. The taxane-resistant gene FSCN1 was also expressed highly in single-cell subclonal populations in mCRPC. Furthermore, metronomic-topotecan single agent and combinations with DTX downregulated these EMT markers as well as CD44+ and CD44+/CD133+ "stem-like" cell populations. A microfluidic chip-based cell invasion assay revealed that METRO-TOPO treatment as a single agent or in combination with DTX was potentially effective against invasive prostate cancer spread. Our RNA-seq and scRNA-seq analysis were supported by in silico and in vitro studies, suggesting METRO-TOPO combined with DTX may inhibit oncogenic progression by reducing cancer stemness in AVPC through the inhibition of EMT markers and multiple oncogenic factors/pathways.

Significance

The utilization of metronomic-like dosing regimens of topotecan alone and in combination with DTX resulted in the suppression of makers associated with EMT and stem-like cell populations in AVPC models. The identification of molecular signatures and their potential to serve as novel biomarkers for monitoring treatment efficacy and disease progression response to treatment efficacy and disease progression were achieved using bulk RNA-seq and single-cell-omics methodologies.

Immune Profile of Exosomes in African American Breast Cancer Patients Is Mediated by Kaiso/THBS1/CD47 Signaling

African American (AA) women with breast cancer are more likely to have higher inflammation and a stronger overall immune response, which correlate with poorer outcomes. In this report, we applied the nanostring immune panel to identify differences in inflammatory and immune gene expression by race. We observed a higher expression of multiple cytokines in AA patients compared to EA patients, with high expression of CD47, TGFB1, and NFKB1 associated with the transcriptional repressor Kaiso. To investigate the mechanism associated with this expression pattern, we observed that Kaiso depletion results in decreased expression of CD47, and its ligand SIRPA. Furthermore, Kaiso appears to directly bind to the methylated sequences of the THBS1 promotor and repress gene expression. Similarly, Kaiso depletion attenuated tumor formation in athymic nude mice, and these Kaiso-depleted xenograft tissues showed significantly higher phagocytosis and increased infiltration of M1 macrophages. In vitro validation using MCF7 and THP1 macrophages treated with Kaiso-depleted exosomes showed a reduced expression of immune-related markers (CD47 and SIRPA) and macrophage polarization towards the M1 phenotype compared to MCF7 cells treated with exosomes isolated from high-Kaiso cells. Lastly, analysis of TCGA breast cancer patient data demonstrates that this gene signature is most prominent in the basal-like subtype, which is more frequently observed in AA breast cancer patients.

Comparative G-Protein-Coupled Estrogen Receptor (GPER) Systems in Diabetic and Cancer Conditions: A Review

For many patients, diabetes Mellitus and Malignancy are frequently encountered comorbidities. Diabetes affects approximately 10.5% of the global population, while malignancy accounts for 29.4 million cases each year. These troubling statistics indicate that current treatment approaches for these diseases are insufficient. Alternative therapeutic strategies that consider unique signaling pathways in diabetic and malignancy patients could provide improved therapeutic outcomes. The G-protein-coupled estrogen receptor (GPER) is receiving attention for its role in disease pathogenesis and treatment outcomes. This review aims to critically examine GPER' s comparative role in diabetes mellitus and malignancy, identify research gaps that need to be filled, and highlight GPER's potential as a therapeutic target for diabetes and malignancy management. There is a scarcity of data on GPER expression patterns in diabetic models; however, for diabetes mellitus, altered expression of transport and signaling proteins has been linked to GPER signaling. In contrast, GPER expression in various malignancy types appears to be complex and debatable at the moment. Current data show inconclusive patterns of GPER expression in various malignancies, with some indicating upregulation and others demonstrating downregulation. Further research should be conducted to investigate GPER expression patterns and their relationship with signaling pathways in diabetes mellitus and various malignancies. We conclude that GPER has therapeutic potential for chronic diseases such as diabetes mellitus and malignancy.

African Ancestry-Associated Gene Expression Profiles in Triple-Negative Breast Cancer Underlie Altered Tumor Biology and Clinical Outcome in Women of African Descent

Women of sub-Saharan African descent have disproportionately higher incidence of triple-negative breast cancer (TNBC) and TNBC-specific mortality across all populations. Population studies show racial differences in TNBC biology, including higher prevalence of basal-like and quadruple-negative subtypes in African Americans (AA). However, previous investigations relied on self-reported race (SRR) of primarily U.S. populations. Due to heterogeneous genetic admixture and biological consequences of social determinants, the true association of African ancestry with TNBC biology is unclear. To address this, we conducted RNA sequencing on an international cohort of AAs, as well as West and East Africans with TNBC. Using comprehensive genetic ancestry estimation in this African-enriched cohort, we found expression of 613 genes associated with African ancestry and 2,000+ associated with regional African ancestry. A subset of African-associated genes also showed differences in normal breast tissue. Pathway enrichment and deconvolution of tumor cellular composition revealed that tumor-associated immunologic profiles are distinct in patients of African descent.

SIGNIFICANCE

Our comprehensive ancestry quantification process revealed that ancestry-associated gene expression profiles in TNBC include population-level distinctions in immunologic landscapes. These differences may explain some differences in race-group clinical outcomes. This study shows the first definitive link between African ancestry and the TNBC immunologic landscape, from an African-enriched international multiethnic cohort. See related commentary by Hamilton et al., p. 2496. This article is highlighted in the In This Issue feature, p. 2483.

Under-representation of Racial Groups in Genomics Studies of Gastroenteropancreatic Neuroendocrine Neoplasms

Not all populations are poised to benefit from advancing genomics in gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs), as genomics have focused on White patients. This study aimed to evaluate racial populations represented in genomic studies of GEP-NENs and to provide evidence of differential genomic findings between racial groups in GEP-NENs. Manuscripts analyzing DNA, RNA, or DNA methylation in GEP-NENs were queried using PUBMED and EMBASE. NIH race/ethnicity term frequency was then determined by Natural Language Processing, followed by manual evaluation of tumor types and subjects by racial group. Immunohistochemistry of institutional tissue micro-arrays and analysis of AACR GENIE data analyzed was performed to determine mutational differences between Black and White pancreatic NEN (pNEN) patients. 313 manuscripts conducted the requisite genomic analyses, 16 of which included subject race data. Race data were included in 13/184 DNA, 4/107 RNA, and 1/54 DNA Methylation analyses. These studies included 89% White subjects (n=2032), 5.8% Asian subjects (n=132), 4.0% “Other” subjects (n=93), and 1.2% Black subjects (n=27). No Native American/Alaska Native, Native Hawaiian/Pacific Islander, or ethnically Hispanic/Latinx subjects were represented. There were significant differences in MEN1 mutations among Black and White patients in immunohistochemical (13:40) and GENIE data (24:268 patients per group, respectively), with 9 additional genes differentially mutated in the GENIE dataset. Genomic sequencing data for GEP-NENs is almost racially homogenous. Differences in pNEN genomics may exist between racial groups, highlighting a need for diversity in future genomic analyses of GEP-NENs to understand the putative influence of interracial genomic variation on GEP-NEN prevention, diagnosis, and therapy.

Poziotinib Inhibits HER2-Mutant-Driven Therapeutic Resistance and Multiorgan Metastasis in Breast Cancer

The pan-HER tyrosine kinase inhibitor (TKI) neratinib is therapeutically active against metastatic breast cancers harboring activating HER2 mutations, but responses are variable and often not durable. Here we demonstrate that recurrent HER2 mutations have differential effects on endocrine therapy responsiveness, metastasis, and pan-HER TKI therapeutic sensitivity. The prevalence and prognostic significance may also depend on whether the HER2 mutant has arisen in the context of lobular versus ductal histology. The most highly recurrent HER2 mutant, L755S, was particularly resistant to neratinib but sensitive to the pan-HER TKI poziotinib, alone or in combination with fulvestrant. Poziotinib reduced tumor growth, diminished multiorgan metastasis, and inhibited mTOR activation more effectively than neratinib. Similar therapeutic effects of poziotinib were observed in both an engineered HER2L755S MCF7 model and a patient-derived xenograft harboring a HER2G778_P780dup mutation. Overall, these findings support the need for clinical evaluation of poziotinib for the treatment of HER2-mutant metastatic breast cancer.

SIGNIFICANCE

Evaluation of the functional impact of HER2 mutations on therapy-induced resistance and metastasis identifies robust antitumor activity of poziotinib and supports the clinical evaluation of poziotinib in ER+ HER2 mutant breast cancer.

Unmet Needs in Oncology Clinical Research and Treatment in Africa: Focus on Ghana

Cancer incidence is increasing worldwide and is a major cause of mortality. The relative magnitude of the increase is remarkably high in low human development index (HDI; 95%) and medium HDI (64%) countries. On the African continent, a corresponding increase in cancer burden is predicted, particularly for sub-Saharan Africa. Current epidemiologic data indicate that mortality rates of certain cancers, such as breast and cervical cancers, in sub-Saharan Africa are the highest in the world, and the cancer risks are broadly comparable to the risks in high-income countries, such as the United States and Europe. Although emerging data alludes to the unique genetic profile of cancer in African populations, most cancer therapies are introduced to Africa without confirmatory clinical trials. Therefore, there is an increasing need for clinical trials directed toward prevention, screening, diagnosis, and identification of innovative treatments in the African context. This review will discuss the increasing cancer burden in Africa, with a particular focus on Ghana, unmet clinical needs in cancer, current medical systems, clinical trial regulatory systems, and challenges to clinical trial recruitment.

Mannose receptor (CD206) activation in tumor-associated macrophages enhances adaptive and innate antitumor immune responses

Solid tumors elicit a detectable immune response including the infiltration of tumor-associated macrophages (TAMs). Unfortunately, this immune response is co-opted into contributing toward tumor growth instead of preventing its progression. We seek to reestablish an antitumor immune response by selectively targeting surface receptors and endogenous signaling processes of the macrophage subtypes driving cancer progression. RP-182 is a synthetic 10-mer amphipathic analog of host defense peptides that selectively induces a conformational switch of the mannose receptor CD206 expressed on TAMs displaying an M2-like phenotype. RP-182-mediated activation of this receptor in human and murine M2-like macrophages elicits a program of endocytosis, phagosome-lysosome formation, and autophagy and reprograms M2-like TAMs to an antitumor M1-like phenotype. In syngeneic and autochthonous murine cancer models, RP-182 suppressed tumor growth, extended survival, and was an effective combination partner with chemo- or immune checkpoint therapy. Antitumor activity of RP-182 was also observed in CD206^high patient-derived xenotransplantation models. Mechanistically, via selective reduction of immunosuppressive M2-like TAMs, RP-182 improved adaptive and innate antitumor immune responses, including increased cancer cell phagocytosis by reprogrammed TAMs.

Strengthening and Sustaining Inter-Institutional Research Collaborations and Partnerships

Inter-institutional collaborations and partnerships play fundamental roles in developing and diversifying the basic biomedical, behavioral, and clinical research enterprise at resource-limited, minority-serving institutions. In conjunction with the Research Centers in Minority Institutions (RCMI) Program National Conference in Bethesda, Maryland, in December 2019, a special workshop was convened to summarize current practices and to explore future strategies to strengthen and sustain inter-institutional collaborations and partnerships with research-intensive majority-serving institutions. Representative examples of current inter-institutional collaborations at RCMI grantee institutions are presented. Practical approaches used to leverage institutional resources through collaborations and partnerships within regional and national network programs are summarized. Challenges and opportunities related to such collaborations are provided.

Abstract IA27: Exploring the impact of African ancestry in tumor immune response, a possible role in disparate clinical outcomes

Disparities in breast cancer survival among ethnic groups have been a persistent finding over the past five decades, exacerbated in part by the lack of improvement to non-white patient outcomes, despite treatment advancements that have improved clinical outcomes in white women. A significant part of this disparity is health equity; however, recent evidence from several groups indicates that histologic and pathologic diversity in tumor phenotypes among ethnic groups is also a key factor affecting the differences in clinical outcome. Specifically, correlated findings among women with significant West African ancestry reveal that there is a genetic link between women across the African Diaspora that is associated with aggressive tumor phenotypes, including triple-negative breast cancer. Aside from the global incidence of TNBC being higher in regions with relatively higher numbers of women with African ancestry, we also find that pathologic progression of tumors in African Americans tends to mimic that of African women. Tumor progression is directly related to the immune response elicited by the onset of tumor growth as well as the underlying tissue microenvironment, particularly the inflammatory status. We have identified several lines of evidence that suggest there is a distinct immune response to breast cancer, which is also tumor phenotype/subtype specific, when comparing patients of significant African ancestry with those of primarily European ancestry. These findings suggest that there could be a unique mechanism of tumor immunology at work, driven by population private genetic alleles derived in Africa and transmitted throughout the African Diaspora, causing a unique tumor phenotype in these breast cancer patients. This unique phenotype is likely the key factor in distinct treatment responses that result in poorer clinical outcomes for African American women.

Citation Format: Melissa B. Davis, Brittany D. Jenkins, Rachel A. Martini, Haythem Ali, Clayton C. Yates, Elizabeth A. Howerth, Petros Nikolinakos, Michele Monteil, Lisa A. Newman. Exploring the impact of African ancestry in tumor immune response, a possible role in disparate clinical outcomes [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr IA27.

Abstract B062: Kaiso influences immune signaling of breast cancer exosomes

Introduction: Exosomes are communication vesicles act as mediator of intracellular transfer of genetic information, act an important role in intercommunication between tumor cells and immune cells. However, the mechanism underlining this cell-cell communication is not well understanding, particularly in African American breast cancer patients. Recently, our lab has demonstrated that Kaiso, a novel bi-modal transcription factor is highly expressed in African American breast cancer and notably, high Kaiso expression correlates with breast cancer aggressiveness and the disparity in survival outcomes of breast cancer patients of African American compared to European American patients. However, the differential expression and biological consequences of Kaiso in immune signaling of breast cancer exosomes has not been studied yet. Herein we demonstrate the biological role of Kaiso in immune signaling in breast cancer exosomes. Methods: In this study we utilized Nanostring immune profiling technology along with multiple in vitro and in vivo assays were used to study the role of Kaiso in breast cancer immune escape. Results: Nanostring pan cancer immune profiling demonstrated that European American breast cancer exosomes exhibited higher expression of TILs markers, T cell activation markers and CD8+T Cells markers compared to African American, while we observed an increase in the expression of the anti-phagocytic molecule CD47 in breast cancer patient exosomes of African American compared to European American patients. In addition to that CD47 and SIRP-α (Signal Regulatory Protein) are highly expressed in Kaiso-scrambled MDA-MB-231 cells (sh-Scr) and exosomes, whereas THBS1, which is a regulator of CD47 expression and is regarded as angiogenesis inhibitor is significantly increased in sh-Kaiso MDA-231 cells and exosomes. Additionally, we observed that Kaiso directly binds methylated sequences in the promoter region of CD47 and THBS1 by ChIP assay. Furthermore, in vivo sh-Kaiso cells injected into athymic mice exhibited delayed tumor formation after four weeks with smaller tumor size as compared to sh-SCR cells, and we observed higher expression of THBS1 with lower expression of CD47 and SIRP-α molecules by IHC and exosomes isolated from invivo tumors, indicating that Kaiso is associated with macrophage mediated immune escape. Conclusion: These findings demonstrate the important role of kaiso in immune signaling through exosomes which may be related with more aggressive cancer phenotype in breast cancer specially in African Americans.

Citation Format: Shakir U Ahmed, Brittany Davis, Benjamin Adu Addai, Balasubramanyanam Karanam, Melissa Davis, William Grizzle, Honghe Wang, Clayton C Yates. Kaiso influences immune signaling of breast cancer exosomes [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr B062.

Abstract 1525: Kaiso influences immune signaling of breast cancer exosomes

Introduction: Exosomes are communication vesicles between tumor cells and immune cells. However, the mechanism underlining this cell-cell communication is not well understanding, particularly in African American (AA) breast cancer patients. Kaiso, a bi-modal transcription factor is highly expressed in AA patients and high Kaiso expression correlates with aggressiveness and the disparity in survival outcomes compared to European American (EA) patients. However, the biological consequences of Kaiso in immune signaling of breast cancer exosomes has not been studied. Herein we demonstrate the biological role of Kaiso in immune signaling in breast cancer exosomes.

Methods: We utilized Nanostring immune profiling technology along with multiple in vitro and in vivo assays to study the role of Kaiso in breast cancer immune escape.

Results: Nanostring pan cancer immune profiling showed that EA breast cancer exosomes exhibited higher expression of TILs markers, T cell activation markers and CD8+T Cells markers compared to AA, while we observed an increase in the expression of anti-phagocytic molecule CD47 in breast cancer patient exosomes of AA compared to EA. In addition to that CD47 and SIRP-α (Signal Regulatory Protein) are highly expressed in Kaiso-scrambled MDA-MB-231 cells (sh-SCR) and exosomes, whereas THBS1, which is a regulator of CD47 expression and is regarded as angiogenesis inhibitor is significantly increased in sh-Kaiso MDA-231 cells and exosomes. Additionally, we observed that Kaiso directly binds methylated sequences in the promoter region of CD47 and THBS1 by ChIP assay. Furthermore, in vivo sh-Kaiso cells injected into athymic mice exhibited delayed tumor formation after four weeks with smaller tumor size as compared to sh-SCR cells, and we observed higher expression of THBS1 with lower expression of CD47 and SIRP-α molecules by IHC and exosomes isolated from invivo tumors, indicating that Kaiso is associated with macrophage mediated immune escape.

Conclusion: Our findings demonstrate the role of kaiso in immune signaling through exosomes which may be related with more aggressive cancer phenotype in breast cancer specially in African Americans.

Citation Format: Md Shakir U. Ahmed, Brittany Jenkins, Benjamin Adu-Addai, Balasubramanyam Karanam, Melissa B. Davis, William E. Grizzle, Honghe Wang, Clayton C. Yates. Kaiso influences immune signaling of breast cancer exosomes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1525.

Proteomic characterization of paired non-malignant and malignant African-American prostate epithelial cell lines distinguishes them by structural proteins

Background

While many factors may contribute to the higher prostate cancer incidence and mortality experienced by African-American men compared to their counterparts, the contribution of tumor biology is underexplored due to inadequate availability of African-American patient-derived cell lines and specimens. Here, we characterize the proteomes of non-malignant RC-77 N/E and malignant RC-77 T/E prostate epithelial cell lines previously established from prostate specimens from the same African-American patient with early stage primary prostate cancer.

Methods

In this comparative proteomic analysis of RC-77 N/E and RC-77 T/E cells, differentially expressed proteins were identified and analyzed for overrepresentation of PANTHER protein classes, Gene Ontology annotations, and pathways. The enrichment of gene sets and pathway significance were assessed using Gene Set Enrichment Analysis and Signaling Pathway Impact Analysis, respectively. The gene and protein expression data of age- and stage-matched prostate cancer specimens from The Cancer Genome Atlas were analyzed.

Results

Structural and cytoskeletal proteins were differentially expressed and statistically overrepresented between RC-77 N/E and RC-77 T/E cells. Beta-catenin, alpha-actinin-1, and filamin-A were upregulated in the tumorigenic RC-77 T/E cells, while integrin beta-1, integrin alpha-6, caveolin-1, laminin subunit gamma-2, and CD44 antigen were downregulated. The increased protein level of beta-catenin and the reduction of caveolin-1 protein level in the tumorigenic RC-77 T/E cells mirrored the upregulation of beta-catenin mRNA and downregulation of caveolin-1 mRNA in African-American prostate cancer specimens compared to non-malignant controls. After subtracting race-specific non-malignant RNA expression, beta-catenin and caveolin-1 mRNA expression levels were higher in African-American prostate cancer specimens than in Caucasian-American specimens. The “ECM-Receptor Interaction” and “Cell Adhesion Molecules”, and the “Tight Junction” and “Adherens Junction” pathways contained proteins are associated with RC-77 N/E and RC-77 T/E cells, respectively.

Conclusions

Our results suggest RC-77 T/E and RC-77 N/E cell lines can be distinguished by differentially expressed structural and cytoskeletal proteins, which appeared in several pathways across multiple analyses. Our results indicate that the expression of beta-catenin and caveolin-1 may be prostate cancer- and race-specific. Although the RC-77 cell model may not be representative of all African-American prostate cancer due to tumor heterogeneity, it is a unique resource for studying prostate cancer initiation and progression.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3462-7) contains supplementary material, which is available to authorized users.

Abstract 5414: Kaiso influences the exosome profile required to induce cell proliferation, migration and metabolism in breast cancer

Purpose: Breast cancer is the most frequent tumor in women, afflicting African American (AA) females to a greater degree than Caucasians (CAs). Recently, we and others have found that Kaiso expression is elevated in AA patients relative to CA patients, and its expression correlates with tumor recurrence and metastasis. Exosomes are considered important modulators of cellular behavior through their cellular communication by transferring mRNA, microRNAs, proteins among cells. Here, we study the role of Kaiso on the biological function of breast cancer exosomes.

Experimental procedures: Exosomes were isolated by ultracentrifugation method and characterized by antibody array. We performed exosome internalization assay, cell proliferation assay and migration assay. Cellular metabolic activity was measured by Seahorse Analyzer. Exosome proteomics was performed by LC-MS/MS and analyzed quantitatively by Panther and DAVID bioinformatics resources.

Results: Isolated exosomes were effectively internalized by MCF7 cells. MCF7 cells treated with exosomes of Kaiso-knock-downed MDA-MB-231 cells (sh-Kaiso) showed a decreased proliferation as compared to exosomes of Kaiso-scrambled MDA-MB-231 cells (sh-Scr). We further observed that treatment of MCF7 cells with sh-Kaiso exosomes decreased cell migration when compared to sh-Scr. To determine the proteins responsible for this observation, we performed exosome proteomics profiling. Exosomes released from sh-Kaiso compared to sh-Scr cells showed differential enrichment of protein expression. In sh-Kaiso exosomes, 36 proteins were down-regulated and most of these proteins are involved in cell invasion and metastasis; whereas 172 proteins were up-regulated in sh-Kaiso of which most of them are involved in protein folding, protein complex assembly, biogenesis and repair. In proteomics data, lactate dehydrogenases (LDH) A&B which are metabolically important proteins and are involved in the critical step of inter-conversion of lactate to pyruvate, expressed differentially between sh-SCR and sh-kaiso. Furthermore, using Seahorse Analyzer we determined enhanced oxygen consumption rate, an indicator of oxidative phosphorylation and elevated extracellular acidification rate, an indicator of enhanced metabolism; in sh-SCR exosome treated MCF7 cells as compared to sh-Kaiso exosome treated MCF7 cells.

Conclusions: Our findings demonstrate that Kaiso plays an important role in the content of exosome cargo, which in turn has an effect promoting cell growth, migration and metabolism of breast cancer cells. We suggest that Kaiso has defined role in limiting important cellular information in breast cancer exosome cargo.

Citation Format: Md Shakir U. Ahmed, Shweta Triphati, William E. Grizzle, Honghe Wang, Clayton C. Yates. Kaiso influences the exosome profile required to induce cell proliferation, migration and metabolism in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5414. doi:10.1158/1538-7445.AM2017-5414

Abstract 1286: Cytokine response of stromal cells to prostate cancer chemotherapeutics

Non-responsiveness to chemotherapeutic drugs presents a significant challenge to the effective treatment of advanced prostate cancer. Exploration of the therapeutic response in prostate cancer has largely focused on the epithelial tumor cells. However, evidence suggests that the tumor microenvironment may modulate response to chemotherapeutics. The tumor microenvironment consists of immune, fibroblastic, and vascular cells, as well as extracellular matrix (ECM) and stromal-derived soluble factors, all of which contribute to interactions within the tumor microenvironment. It has been demonstrated that tumor cells cross-talk with stromal cells, to establish a protective niche at primary and distant sites and to facilitate survival of cancer cells. Such tumor-stroma cell cross-talk often involves secreted factors, such as cytokines. Previous studies have illustrated the importance of cytokines and cytokine receptors as modulators of drug response. In this study, we sought to identify cytokine factors expressed in response to drugs clinically used to control prostate cancer. To obtain the expression profiles, we conducted a human cytokine and chemokine array, which consisted of 84 specific genes. Analysis of the prostate cancer and stromal cells treated with Docetaxel (4nM), Enzalutamide (30μM) and Bicalutamide (30μM) revealed differential expression patterns. The effect of chemotherapeutics on the expression of the cytokine IL-16 and its cognate receptors CD9 and CCR5 in prostate cancer and stromal cell lines was further examined. We found IL-16 expression increased several fold following chemotherapeutic treatment in stromal cell lines compared to prostate cancer cell lines. To validate gene expression, we examined the expression of IL-16 and its receptors by RT-PCR. All experiments were performed in triplicates. Student t- tests were used to determine the statistical significance between groups. IL-16 expression increased following exposure to chemotherapeutics in stromal cell lines. CCR5 expression showed a decrease in PC3 prostate cancer cells but no significant changes were observed in LNCaP cells. CD9 expression showed an increase in both LNCaP and PC3 cell lines. Collectively, these results indicate that chemotherapy of prostate cancer may alter the expression of IL-16 and its receptors. We hypothesize that IL-16 is a soluble stromal factor that is expressed in response to anticancer drugs, and may have paracrine activity on neighboring cells that express the cognate receptors.

Citation Format: Dominique Gales, Clayton C. Yates, Temesgen Samuel. Cytokine response of stromal cells to prostate cancer chemotherapeutics. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1286.

Abstract PL01-02: Functional biomarkers that promote African American prostate cancer through epigenetic regulation

Prostate cancer is the most commonly diagnosed malignancy in men, with African American men experiencing a rate 60% higher than white patients. At the time of diagnosis, approximately 50% of men have clinically advanced disease. African American men have almost twice the incidence and death rates related to prostate cancer compared to Caucasian men. Several studies have suggested that some of these differences may be attributed to the elevated expression of different genes. Many factors have been associated with why prostate tumors in AA patients are more aggressive. However there is a lack of knowledge, whether this is the result of genes that promote aggressiveness or promote tumor development. Methylation profiling of prostate tumors has demonstrated that the loss of a number of key regulatory genes are not via mutation, but rather hypermethylation. This is particularly evident in the AA patients where hypermethylation of a number of genes in normal or pre-malignant areas are thought to predispose a full-blown malignancy. However the underlining mechanism of these acquired methylation patterns is poorly understood. To better understand the epigenetic regulation of genes associated with promoting aggressiveness and specifically to determine if this can explain the more aggressive nature of AA tumors , we conducted 662 microRNA microarray profiling utilizing novel isogenic non-malignant and malignant cell lines derived from both AA and CA tumor patients. Utilizing multiple criteria, included pathological stage and race, we were able to determine a distinct microRNA signature that was unique the AA derived cell lines, independent of tumor status. Validation by q-PCR of the 10 most significantly differentially expressed miRNA's across our 11 cell line panel demonstrated that loss of miR-152 expression was associated with aggressiveness. Restoring miR-152 expression in miR-152 deficient cell lines, resulted in decreased proliferation, and S phase arrest of the cell cycle. In silico informatics analysis predicted that miR-152 contains a significant number of CpG islands within the promoter region upstream of the start site. We confirmed this analysis with bisulfite conversion and sequencing of the promoter, as well as treatment with demethylation agent 5-Aza-2′-deoxycytidine. Furthermore, we observed an inverse relationship of miR-152 with predicted target DNA methyltransferase-1 (DNMT1), suggesting a reciprocal maintenance of hypermethylation for not only miR-152, but also a number of other methylated genes. This is plausible given the well-established role of DNMT1 in methylation of a large number of genes found to promote aggressiveness in prostate tumors . Lastly, a comparison of normal/tumor ratios of miR-152 expression in 20 CA and 20 AA prostate cancer patients, we observed significantly decreased expression in tumors from CA patients as expected, however this was not observed in AA patients. AA patients also displayed an overall lower expression compared to CA tumors. In summary, these results are the first to identify unique miRNAs that contribute to aggressive prostate cancers in AA patients. Furthermore epigenetic regulation of the miR-152/DNMT1 regulatory loop may play an import ant role in multiple events that contribute to the aggressiveness of PCa tumors.

Citation Format: Shaniece C. Theodore, Honghe Wang, Jhong Rhim, Timothy Turner, Melissa Davis, William Grizzle, Clayton C. Yates. Functional biomarkers that promote African American prostate cancer through epigenetic regulation. [abstract]. In: Proceedings of the Sixth AACR Conference: The Science of Cancer Health Disparities; Dec 6–9, 2013; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2014;23(11 Suppl):Abstract nr PL01-02. doi:10.1158/1538-7755.DISP13-PL01-02

Abstract C70: ABCD3 expression in prostate and breast tumors

Background: In a previous study, we identified the ABCD3 gene as important in aggressive prostate tumors. The ABCD3 gene is a member of the ABC (ATP-Binding Cassette) family. The ABC gene family give instructions for making transporter proteins that carry many types of molecules, such as fats, sugars, protein building blocks (amino acids) and drugs, across cell membranes and is known to play a role in chemoresistance is some cancers.

Purpose: Little is known about role of ABCD3 in prostate cancer, hence in the present study we assessed the expression of ABCD3 in normal and malignant prostate tissue (without regard to racial ethnicity) and determined correlations between ABCD3 expression and clinicopathologic characteristics.

Methods: Clinically annotated duplicate core tissue high-density prostate adenocarcinoma tissue microarray of 92 cases of adenocarcinoma, 2 prostate transitional cell carcinoma, 12 prostate adjacent normal tissue and 8 normal prostate tissue were stained with a monoclonal antibody against ABCD3 and scored for percentage of visible staining.

Results: Increased ABCD3 expression correlated with increasing Gleason score (p=0.0094), age (p=0.0014) and pathology grade (p=0.0007). Interestingly, we also observed that ABCD3 expression was elevated to varying degrees in other types of cancers, breast (stage II a), brain, cervical, head and neck, kidney and pancreatic.

Conclusions: We postulate that ABCD3 may be a putative prognostic biomarker that discriminates between indolent and aggressive cancers, albeit ABCD3 function in cancer progression is still under investigation.

Citation Format: R. Renee Reams, Jacqueline D. Jones, Daniel Osborne, Honghe Wang, Clayton C. Yates, III. ABCD3 expression in prostate and breast tumors. [abstract]. In: Proceedings of the Sixth AACR Conference: The Science of Cancer Health Disparities; Dec 6–9, 2013; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2014;23(11 Suppl):Abstract nr C70. doi:10.1158/1538-7755.DISP13-C70

Does daily kangaroo care provide sustained pain and stress relief in preterm infants?

OBJECTIVES

1. Determine whether stress in preterm infants, measured with salivary cortisol, decreases after five days of Kangaroo Care (KC) compared to five days of Standard Care (SC). 2. To determine whether kangaroo care provides sustainable pain relief beyond the period of skin-to-skin holding.

STUDY DESIGN

Preterm infants (n = 38) born at 27-30 weeks gestational age were randomized to either the KC or the SC group and received the allocated intervention starting on day of life (DOL) five and continuing for five days. Salivary cortisol was collected on DOL five and again on DOL ten. Differences were analyzed using repeated measures ANOVA and t tests. Pain during nasal suctioning over five days was assessed using the Premature Infant Pain Profile (PIPP).

RESULT

1. Adequate saliva samples for salivary cortisol were collected for 13 KC infants and 11 SC infants. There was no main effect of group (p = 0.49), but there was a significant main effect of age (DOL five versus DOL ten), with salivary cortisol levels decreasing in both groups (p = 0.02). 2. Pain scores for both groups (n = 38) indicted mild to moderate pain during suctioning, with no significant difference in pain scores between groups.

CONCLUSION

1. KC did not affect salivary cortisol levels in preterm neonates, but levels in both the KC and SC groups decreased over time from DOL five to ten. Salivary cortisol may vary with age of infant. 2. Infants experience pain during routine suctioning and may require pain management.

Abstract P1-07-07: Targeting reversal of epithelial-mesenchymal transition through FOXM1 inhibition in breast cancer cells

Purpose: Triple-negative breast cancer (TNBC), representing up to 20% of all breast cancer cases, is a highly diverse group of cancer that is associated with an aggressive phenotype, with affected patients having a poorer prognosis. Its treatment has been challenging due to its heterogeneity and the absence of well-defined molecular targets.

Epithelial-to-mesenchymal transition (EMT) is one of the hallmarks of aggressive breast cancers and is associated with increased metastatic potential. TNBCs have been shown to exhibit elevated EMT. Thus, reversal of EMT has been identified as a viable target in the treatment of aggressive breast cancers.

FOXM1 is an oncogenic transcription factor of the Forkhead family and it has a well-defined role in cell proliferation and cell-cycle progression. FOXM1 has been reported to be over-expressed in breast cancer. In prostate cancer, FOXM1 overexpression has been linked to increase EMT. We have previously shown that targeting NF-kB with panepoxydone (PP), an NF-kB inhibitor isolated from Lentinus crinitus (an edible mushroom), has significant antitumor activity against breast cancer cells with a resultant decrease in cell migration and invasion and induction of apoptosis. We have further identified that the FOXM1 promoter has a binding site for NF-kB. Thus, in this study, we investigated whether PP-induced inhibition of breast cancer cell growth could be attributed to FoxM1 activity and EMT reversal.

Experimental Design: The estrogen receptor positive (MCF-7) and three different triple negative (MDA-MB-231, MDA-MB-453, and MDA-MB-468) breast cancer cell lines were selected to observe the effect of PP on FOXM1and EMT markers.

Results: In the current study, we investigated whether panepoxydone- induced inhibition of breast cancer cell growth could be attributed to FoxM1activity and EMT reversal. Breast cancer cells were treated with increasing concentrations of PP and proteins collected after 24 hrs. Panepoxydone treatment significantly reduced FOXM1 expression in MCF-7 and MDA-MB-231 (1.7 and 2.4-fold, respectively, p &lt; 0.05) but not in MDAMB-453 and MDAMB-468 cells when analyzed through western blot analysis. Furthermore, we showed that treatment with PP resulted in alteration of EMT-associated proteins with a significant increase in E-cadherin in all the cell lines (ranging from 1.8 to 4.2-fold, p &lt; 0.05) and a decrease in mesenchymal markers vimentin and zeb1 in the MDA-MB-231 cells (2.5 and 2-fold respectively, p &lt; 0.05).

To further elucidate the relationship between FOXM1 on EMT reversal, we then silenced FOXM1 in MDA-MB-231 cells and evaluated its effect on the EMT-associated markers. Again we noted upregulation of E cadherin (3.5-fold, p&lt; 0.01) and down-regulation of vimentin (4.5-fold, p &lt;0.01) in FOXM1, which was very similar to what was observed in the PP-treated MDA-MB-231 cells.

Conclusion: These studies show, for the first time, the role of FOXM1 in EMT reversal in breast cancer cells. Furthermore, it shows that use of an NF-kB inhibitor, such as panepoxydone, may be helpful in elucidating the relationship between these two transcriptional factors, in the reversal of the EMT phenotype in aggressive breast cancer cells.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-07-07.

Modafinil normalized hyperreflexia after spinal transection in adult rats

STUDY DESIGN

Hyperreflexia occurs after spinal cord injury and can be assessed by measuring low frequency-dependent depression of the H-reflex in the anesthetized animal.

OBJECTIVE

To determine the effects of Modafinil (MOD), given orally, following a complete SCI compared with animals receiving MBET and transected untreated animals and examine if changes exist in Connexin 36 (Cx-36) protein levels in the lumbar enlargement of animals for the groups described.

SETTING

Center for Translational Neuroscience, Little Rock, AR, USA.

METHODS

Adult female rats underwent complete transection (Tx) at T10 level. H-reflex testing was performed 30 days following Tx in one group, and after initiation of treatment with MOD in another group, and after MBET training in the third group. The Lumbar enlargement tissue was harvested and western blots were performed after immunoprecipitation techniques to compare Cx-36 protein levels.

RESULTS

Statistically significant decreases in low frequency-dependent depression of the H-reflex were observed in animals that received MOD and those that were treated with MBET compared with the Tx, untreated group. Statistically significant changes in Cx-36 protein levels were not observed in animals treated with MOD compared with Tx, untreated animals.

CONCLUSION

Normalization of the loss of low frequency -dependent depression of the H-reflex was demonstrated in the group receiving MOD and the group receiving MBET compared with the Tx, untreated group. Further work is needed to examine if Cx-36 protein changes occur in specific subregions of the spinal cord.

Co-culturing human prostate carcinoma cells with hepatocytes leads to increased expression of E-cadherin

Metastasis is a multi-step process wherein tumour cells detach from the primary mass, migrate through barrier matrices, gain access to conduits to disseminate, and subsequently survive and proliferate in an ectopic site. During the initial invasion stage, prostate carcinoma cells undergo epithelial–mesenchymal-like transition with gain of autocrine signalling and loss of E-cadherin, hallmarks that appear to enable invasion and dissemination. However, some metastases express E-cadherin, and we found close connections between prostate carcinoma cells and hepatocytes in a liver microtissue bioreactor. We hypothesise that phenotypic plasticity occurs late in prostate cancer progression at the site of ectopic seeding. Immunofluorescence staining for E-cadherin in co-cultures of hepatocytes and DU-145 prostate cancer cells revealed E-cadherin upregulation at peripheral sites of contact by day 2 of co-culture; E-cadherin expression also increased in PC-3 cells in co-culture. These carcinoma cells bound to hepatocytes in an E-cadherin-dependent manner. Although the signals by which the hepatocytes elicited E-cadherin expression remain undetermined, it appeared related to downregulation of epidermal growth factor receptor (EGFR) signalling. Inhibition of autocrine EGFR signalling increased E-cadherin expression and cell–cell heterotypic adhesion; further, expression of a downregulation-resistant EGFR variant prevented E-cadherin upregulation. These findings were supported by finding E-cadherin and catenins but not activated EGFR in human prostate metastases to the liver. We conclude that the term epithelial–mesenchymal transition only summarises the transient downregulation of E-cadherin for invasion with re-expression of E-cadherin being a physiological consequence of metastatic seeding.

The pressure-flow method: some fundamental concepts

The pressure-flow method introduced by Warren and DuBois is a useful method for estimating velopharyngeal orifice area. However, this investigation shows that unless geometric similarity of subject and model exists, the value of the flow coefficient k used in the equation to estimate velopharyngeal orifice area cannot be established from model tests. Use of k = 0.65 is questioned as that value is typical of thin plate orifices, a geometry that is not a good representation of the velopharyngeal passage. Values of k from the literature and from steady state tests using a model similar to Warren's are presented to show the effect of various inlet shapes. The influence of inlet shape supports the conclusion that k may be significantly higher than 0.65, conceivably approaching values in the range of 0.9 to 0.97, depending on the orifice geometry.