African American Triple Negative Breast Research Articles

Quantitative assessment of the immune microenvironment in African American Triple Negative Breast Cancer: a case\u2013control study

PurposeTriple negative breast cancer (TNBC) is more common in African American (AA) than Non-AA (NAA) population. We hypothesize that tumor microenvironment (TME) contributes to this disparity. Here, we use multiplex quantitative immunofluorescence to characterize the expression of immunologic biomarkers in the TME in both populations.Patients and methodsTNBC tumor resection specimen tissues from a 100-patient case: control cohort including 49 AA and 51 NAA were collected. TME markers including CD45, CD14, CD68, CD206, CD4, CD8, CD20, CD3, Ki67, GzB, Thy1, FAP, aSMA, CD34, Col4, VWF and PD-L1 we quantitatively assessed in every field of view. Mean expression levels were compared between cases and controls.ResultsAlthough no significant differences were detected in individual lymphoid and myeloid markers, we found that infiltration with CD45+ immune cells (p = 0.0102) was higher in TNBC in AA population. AA TNBC tumors also had significantly higher level of lymphocytic infiltration defined as CD45+ CD14− cells (p = 0.0081). CD3+ T-cells in AA tumors expressed significantly higher levels of Ki67 (0.0066) compared to NAAs, indicating that a higher percentage of AA tumors contained activated T-cells. All other biomarkers showed no significant differences between the AA and NAA group.ConclusionsWhile the TME in TNBC is rich in immune cells in both racial groups, there is a numerical increase in lymphoid infiltration in AA compared to NAA TNBC. Significantly, higher activated T cells seen in AA patients raises the possibility that there may be a subset of AA patients with improved response to immunotherapy.

Abstract B042: Loss of nuclear alpha catenin contributes to chemoresistance and aggressive disease in African American triple-negative breast cancer patients

Abstract Triple-negative breast cancer (TNBC) is a particularly aggressive, difficult-to-treat subtype of the disease. A well-documented health disparity exists within TNBC: African American (AA) women are more likely to be diagnosed with and die from the disease. Our group reported homozygous deletions in the CTNNA1 gene, which encodes the protein alpha catenin, in AA TNBC. We have undertaken a basic and translational research study to understand the mechanistic role and clinical impact of alpha catenin loss in TNBC, particularly in AA patients. To validate our findings of alpha catenin loss in TNBC, we analyzed over 600 breast cancer patient samples by immunohistochemistry. We found that alpha catenin protein loss was inversely correlated with survival in TNBC. Moreover, loss was observed more frequently in tumors from AA patients. Interestingly, both nuclear and cytosolic alpha catenin adhered to this pattern. While its cytosolic role has been well studied, little is known about nuclear alpha catenin and its role in disease. To understand the nuclear function of alpha catenin, we developed several isogenic cell line pairs. Using CRISPR/Cas9-mediated gene editing, we generated CTNNA1 knockout (KO) BT-549 and MB-MDA-436 cell lines. We also reintroduced CTNNA1 into MDA-MB-468 cells—a line derived from an AA woman with an endogenous deletion in CTNNA1. Using these models, we found that alpha catenin KO cells demonstrated greater capacity for anchorage-independent growth. Loss of alpha catenin also resulted in decreased sensitivity to DNA-damaging chemotherapies including platinum salts (cisplatin, carboplatin), topoisomerase poisons (doxorubicin, etoposide), and the PARP inhibitor olaparib. This is clinically relevant as doxorubicin, carboplatin, and olaparib are approved for treatment of TNBC patients. To identify binding partners, we performed co-immunoprecipitation of alpha catenin from nuclear lysates, followed by mass spectrometry. We found that nuclear alpha catenin can interact directly with ATR, a kinase critical to the DNA damage response (DDR). ATR mediates both the repair of DNA lesions and the G2/M cell cycle checkpoint, which ensures that only cells with undamaged DNA may enter mitosis. We further found that alpha catenin KO cells were more sensitive to inhibitors of ATR, as well as to inhibitors of the G2/M checkpoint proteins Chk1 and Wee1. Tellingly, the KO cells were less sensitive to inhibitors of ATM or DNA-PK, two regulators of alternate DDR pathways. This suggests that nuclear alpha catenin likely plays a specific role in ATR-directed processes. In our study, we have identified nuclear alpha catenin as a tumor suppressor that affects TNBC's susceptibility to chemotherapy by playing a role in the DDR and the G2/M checkpoint. Our data suggest that loss of alpha catenin is more common in AA patients, and is associated with poor prognosis. Therefore, CTNNA1 status may be important in determining appropriate therapeutic strategies in a subset of patients. Citation Format: Rania Bassiouni, Victoria Dirgo, Krystine Mansfield, Ritin Sharma, Lee D. Gibbs, Patrick Pirrotte, Nasreen Vohra, Kevin Gardner, John D. Carpten. Loss of nuclear alpha catenin contributes to chemoresistance and aggressive disease in African American triple-negative breast cancer patients [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 B042.

Abstract B055: Characterization of immune cell subsets from tissue expression profiles in African American triple-negative breast cancer patients

Abstract Triple-negative breast cancer (TNBC) is more frequent and aggressive in African American women and women of African descent. The heterogeneity of TNBC has become a challenge in today's clinical practice, and significant research efforts have been deployed to better understand the molecular nature of TNBC. Clinically, the heterogeneous nature of TNBC has not been accounted for, hence leading to therapy resistance, metastasis, and relapse. TNBC has been associated with an elevation of immune infiltrates, which suggests that some patients may benefit from immune-based therapies. In this study, we used analytical tools that perform cell type enrichment analysis and provide an estimation of the abundances of immune cell types in a mixed cell population using gene expression data to compare the differences among immune cell types between African and Caucasian American breast cancer patient samples. Here, we examined RNA-sequencing data from 1,215 patients from two breast cancer cohorts including The Cancer Genome Atlas, which consists of 32 African American and 64 Caucasian TNBC samples, and data from 130 breast cancer cases with extensive clinical annotation collected and accrued from rural regions of eastern North Carolina in collaboration with Noreen Vohra at the Brody School of Medicine at East Carolina University. This cohort contained data from 23 African American TNBC samples and 25 Caucasian TNBC samples. Results revealed that tumor-associated macrophages and T cells were significantly represented among TNBC patients in both datasets with uncommitted macrophages (M0), M2-like macrophages, and CD4 memory resting cells as the predominant populations. Additionally, known antitumor immune cells, such as CD8 T cells and NK cells, were under-represented among TNBC patients. Although expression of immune cells and immune cell subsets was represented in our datasets, we did not find any significant difference between African American and Caucasian TNBC patients. We plan to present analyses from this data stratifying cases by mutational burden and expression of immune checkpoint markers. Our findings suggest that TNBC patients could possibly benefit from immunotherapies and their therapy could be personalized to their immune profile. Therefore, immune profiling may unlock new therapeutic opportunities for African American TNBC patients. Citation Format: Lee D. Gibbs, Jung Byun, Tingfen Yan, Anna Napoles, Eliseo Pere-Stables, Troy McEachron, Nasreen Vohra, John D. Carpten, Kevin Gardner. Characterization of immune cell subsets from tissue expression profiles in African American triple-negative breast cancer patients [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 B055.

Abstract P6-06-12: Upregulation of beige adipocytes in African-American triple negative breast tumors induce tumorigenesis by promoting anti-inflammatory microenvironment

Abstract Background: The complexity of breast cancer (BC) development and progression is heavily influenced by the cross-talk of critical cell types within the tumor microenvironment. While there have been many advancements in BC treatment, triple negative breast cancer (TNBC) still exhibits the lowest rate of response and the nature of its aggressive properties remain poorly understood. African American (AA) women are disproportionally affected and have worse overall survival. Our lab previously reported important role of beige adipocytes in breast tumor growth. Interestingly, we found beige adipocytes were highly up regulated in AA TN breast tumors when compared to TNBC from Caucasian (CA) women. In this study, we have further investigated the mechanisms that increase beige adipocytes in AA TN breast tumors and their influence on breast tumor growth. Methods: Human tumor samples provided by Cooperative Human Tissue Network and National Disease Research Institute were subjected to immunohistochemistry (IHC) and western blot analysis to examine key beige adipocyte markers. To further investigate the mechanisms by which beige adipocytes may contribute tumor growth, xenografts were established from AA TNBC cell lines HCC70, HCC1806 and MDA-MB 468. Tumors excised at various time points were examined for beige adipocyte markers and their key regulators using validated species specific primers to distinguish between host and tumor cell contributions. Boyden chamber assays and ex-vivo experiments were performed to examine whether beige adipocytes were recruited from the host or induced in xenografts, and test whether paracrine secretion of cytokines or contact between various cell types were necessary for adipose browning in these tumors. Possible involvement of lactic acid-mediated adipose browning in these tumors was tested by inhibiting lactate dehydrogenase using sodium oxamate. We further examined whether increased browning in these tumors was associated with increase in anti-inflammatory cytokines that promote M2 macrophage phenotype and angiogenesis, both of which are highly implicated in tumor progression. Results: Both quantitative IHC and western blot analysis showed higher expression of beige adipocyte markers CD137 and TMEM26 in AA TNBC compared to CA TNBC. Expression of beige marker CD137 was detected in all xenografts from AA TNBC by IHC. Quantitative gene expression analysis (qPCR) revealed that host contributed to the origin of beige adipocytes in these tumors. We demonstrate using Boyden Chamber assay that contact between tumor cells and host adipocytes was important for adipose browning. Ex-vivo experiments also showed that breast cancer cells in contact with either host adipocytes or 3T3-L1 mouse adipocyte cell line increased the expression of beige markers that could be attenuated by lactate dehydrogenase inhibitor. We further show that increase in beige adipocytes in AA TNBC was associated with high anti-inflammatory cytokines IL13/IL4 expression, as well as anti-inflammatory pro-tumorigenic M2 macrophages and high angiogenesis. Conclusion: Key beige markers CD137 and TMEM26 are significantly upregulated in AA TNBC compared to the CA TNBC. Host microenvironment contributed to beige adipocyte characteristics in response to lactic acid-mediated adipose browning of tumor cells. Furthermore, beige adipocytes increased anti-inflammatory cytokines that facilitate accumulation of M2 macrophages and promote angiogenesis. Our results implicate that beige adipocytes are key mediators of aggressive tumor development in AA TNBC and could potentially be targeted for therapeutic purposes. Citation Format: Brandis A. Moore, Briana Osorio, Rajan Singh, Shehla Pervin. Upregulation of beige adipocytes in African-American triple negative breast tumors induce tumorigenesis by promoting anti-inflammatory microenvironment [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P6-06-12.

Serum exosomal-annexin A2 is associated with African-American triple-negative breast cancer and promotes angiogenesis

BackgroundLimited information is available on biomarker(s) for triple-negative breast cancer (TNBC) that can address the higher incidence and aggressiveness of TNBC in African-American (AA) women. Our previous studies have demonstrated annexin A2 (AnxA2) association with exosomes which promotes angiogenesis and metastasis. Therefore, our goal was to examine the expression and function of exosomal-annexin A2 (exo-AnxA2) derived from the serum samples of breast cancer patients.MethodsThe expression of serum exo-AnxA2 and its association with clinicopathological features of the breast cancer patients were determined. The role of serum exo-AnxA2 to promote angiogenesis was determined by an in vivo Matrigel plug assay.ResultsOur results show that the expression of serum exo-AnxA2 in breast cancer patients (n = 169; 83.33 ± 2.040 ng/mL, P < 0.0001) is high compared to non-cancer females (n = 68; 34.21 ± 2.238 ng/mL). High expression of exo-AnxA2 levels in breast cancer was significantly associated with tumor grade (P < 0.0001), poor overall survival (hazard ratio (HR) 2.802; 95% confidence intervals (CI) = 1.030–7.620; P = 0.0353), and poor disease-free survival (HR 7.934; 95% CI = 1.778–35.398; P = 0.0301). The expression of serum exo-AnxA2 levels was significantly elevated in TNBC (n = 68; 109.1 ± 2.905 ng/mL; P < 0.0001) in comparison to ER+ (n = 50; 57.35 ± 1.545 ng/mL), HER2+ (n = 59; 78.25 ± 1.146 ng/mL), and non-cancer females (n = 68; 34.21 ± 2.238 ng/mL). Exo-AnxA2 showed diagnostic values with a maximum AUC as 1.000 for TNBC, 0.8304 for ER+, and 0.9958 for HER2+ compared to non-cancer females. The expression of serum exo-AnxA2 was significantly elevated in AA women with TNBC (n = 29; 118.9 ± 4.086 ng/mL, P < 0.0001) in comparison to Caucasian-American TNBC (n = 27; 97.60 ± 3.298 ng/mL) patients. Our in vivo results suggest a role of serum exo-AnxA2 in angiogenesis and its association with aggressiveness of TNBC in AA women.ConclusionsOur results demonstrated that the expression of serum exo-AnxA2 is high in AA women with TNBC and promotes angiogenesis. These findings suggest that exo-AnxA2 holds promise as a potential prognosticator of TNBC and may lead to an effective therapeutic option.

ANXA2 expression in African American triple-negative breast cancer patients

Our aim was to determine the role of Annexin A2 (AnxA2), which we have previously found to contribute to the aggressiveness of TNBC, with AA TNBC patients and clinical outcome. We analyzed TCGA breast cancer database (n = 1098) to observe AnxA2 expression within breast cancer subtypes and is correlation with overall survival. Further, we examined breast tissue specimens (n = 119) through chromogenic in situ hybridization (CISH) and specimen were scored independently by two pathologists in a blinded study. In our TCGA analysis, high expression of AnxA2 was correlated with poor survival in patients with TNBC. AnxA2 gene expression was not correlated with poor survival in other breast cancer subtypes. AnxA2 average CISH intensity score (CISH score = 0, null expression to 3, high expression) for TNBC was significantly higher in comparison to estrogen receptor and/or progesterone receptor positive, human epidermal growth factor positive, and non-malignant tissues. Furthermore, AnxA2 average score was significantly higher in AA TNBC patients (CISH average score = 2.45 ± 0.3266) in comparison to Caucasian TNBC patients (CISH average score = 1.1 ± 0.4069). AnxA2 is overexpressed in TNBC, implicating AnxA2 as a contributor to the aggressive biology of TNBC in AA women.

Abstract PR02: β-Catenin overexpression underlies the aggressive disease course in African American triple-negative breast cancer patients who lack androgen receptor

Abstract Background: Androgen receptor (AR) has emerged as a new target for treating TNBC. AR is expressed in 10-43% of TNBCs. Although there are conflicting reports in the literature about the effect of AR status on TNBC prognosis, agents targeting AR signaling (enzalutamide) are already being evaluated in AR-positive TNBCs in early-stage clinical trials. However, no study so far has evaluated the association/correlation of AR status with ethnicity in TNBCs and downstream effects of AR loss in TNBCs. Given the association of AR loss with poor prognosis in breast cancer and that the African American (AA) with TNBC suffers aggressive disease course when compared to European American (EA) TNBCs, we hypothesized that AR loss might be an underlying cause of aggressive disease course in AR-negative TNBCs. Thus, in this project we aimed to study if loss or gain of AR in AA and EA TNBCs regulates the expression of β-catenin and leads to more aggressive disease course by activating downstream canonical Wnt-beta catenin signaling. Methods: We evaluated AR expression immunohistochemically in 424 formalin-fixed, paraffin-embedded samples from TNBC patients for whom complete clinicopathologic and overall survival (OS) data were available. Samples with &amp;lt;1% nuclear-stained cells were considered quadruple-negative. We also performed gene set enrichment analysis for the AR low and high group in AA and EA TNBCs using the publicly available TCGA gene dataset. Finally, we compared levels of 187 proteins with suspected involvement in breast tumorigenesis in AR-high vs AR-low TNBCs (using median AR expression as a cutpoint, as the IHC-derived AR status of these samples was unknown). Results: IHC staining of AR indicated that 79.5% of AA TNBCs (n=214) and 70% of EA TNBCs (n=210) were AR negative. Loss of AR was associated with poor overall survival in adjuvant-treated high Ki67 (&amp;gt;14%) (HR=1.72; p=0.095) AA TNBC (n=98) when compared to EA TNBCs (n=80). These data were validated by our in silico findings, which suggested that EA TNBCs (n=81) exhibited higher levels of AR mRNA compared to AA TNBCs (n=41) (p&amp;lt;0.05). Similarly, AR protein expression was higher in EA TNBCs (n=75) than AA TNBCs (n=32) (p&amp;lt;0.05). We further observed that β-catenin protein levels are higher in AA AR-low TNBCs compared with AA AR-high TNBCs (median AR expression used as cut point; p&amp;lt;0.05). This was strengthened by our observation in a cohort of 142 TNBCs wherein AAs with AR-negative TNBC showed a preponderance of cells with nuclear β-catenin staining via IHC compared with EA TNBCs that lack AR. Our GSEA analysis results indicated that Wnt/β-catenin signaling was the top-enriched gene ontology in the AR-low subgroup compared to AR-high subgroup of TNBCs. Furthermore, proteomic data revealed that β-catenin and Dvl3 expression was significantly upregulated in the AR-low subgroup when compared with AR-high group, suggesting that Wnt signaling is in an overdrive in the AR-low subgroup, especially in AA TNBCs. Conclusion: This study suggests that increased expression of β-catenin coupled with AR loss in AAs may underlie the ethnic disparity in outcomes among TNBC patients and strongly supports the prognostic role of AR and β-catenin in this breast cancer subtype. Citation Format: Karuna Mittal, Shristi Bhattarai, Sergey Klimov, Uma Krishnamurthi, Xiaoxian Li, Ceyda Sonmez Wetherilt, Mohammad A. Aleskandaran, Andrew A. Green, Emad A. Rakha, Ian O. Ellis, Guilherme Cantuaria, Guanhao Wei, Remus Mihai Osan, Meenakshi V. Gupta, Upender Manne, Padmashree C.G Rida, Ritu Aneja. β-Catenin overexpression underlies the aggressive disease course in African American triple-negative breast cancer patients who lack androgen receptor [abstract]. In: Proceedings of the Tenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2017 Sep 25-28; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2018;27(7 Suppl):Abstract nr PR02.

Increased sensitivity of African American triple negative breast cancer cells to nitric oxide-induced mitochondria-mediated apoptosis.

BackgroundBreast cancer is a complex heterogeneous disease where many distinct subtypes are found. Younger African American (AA) women often present themselves with aggressive form of breast cancer with unique biology which is very difficult to treat. Better understanding the biology of AA breast tumors could lead to development of effective treatment strategies. Our previous studies indicate that AA but not Caucasian (CA) triple negative (TN) breast cancer cells were sensitive to nitrosative stress-induced cell death. In this study, we elucidate possible mechanisms that contribute to nitric oxide (NO)-induced apoptosis in AA TN breast cancer cells.MethodsBreast cancer cells were treated with various concentrations of long-acting NO donor, DETA-NONOate and cell viability was determined by trypan blue exclusion assay. Apoptosis was determined by TUNEL and caspase 3 activity as well as changes in mitochondrial membrane potential. Caspase 3 and Bax cleavage, levels of Cu/Zn superoxide dismutase (SOD) and Mn SOD was assessed by immunoblot analysis. Inhibition of Bax cleavage by Calpain inhibitor, and levels of reactive oxygen species (ROS) as well as SOD activity was measured in NO-induced apoptosis. In vitro and in vivo effect of NO treatment on mammary cancer stem cells (MCSCs) was assessed.Results and discussionNO induced mitocondria-mediated apoptosis in all AA but not in CA TN breast cancer cells. We found significant TUNEL-positive cells, cleavage of Bax and caspase-3 activation as well as depolarization mitochondrial membrane potential only in AA TN breast cancer cells exposed to NO. Inhibition of Bax cleavage and quenching of ROS partially inhibited NO-induced apoptosis in AA TN cells. Increase in ROS coincided with reduction in SOD activity in AA TN breast cancer cells. Furthermore, NO treatment of AA TN breast cancer cells dramatically reduced aldehyde dehydrogenase1 (ALDH1) expressing MCSCs and xenograft formation but not in breast cancer cells from CA origin.ConclusionsEthnic differences in breast tumors dictate a need for tailoring treatment options more suited to the unique biology of the disease.

Abstract PR04: The molecular biology of nuclear and mitochondrial regulatory noncoding RNAs differs between white and African American patients with triple-negative breast cancer

Abstract Noncoding RNAs (ncRNAs) are molecules that do not code for proteins but regulate cell physiology via multiple mechanisms. Through studies of hundreds of human datasets from healthy individuals and patients we found for two categories of ncRNAs that their composition and abundances depend on a person's gender, population, race, and several other variables. These two categories are: a) isoforms of microRNAs (miRNAs), also known as isomiRs; and, b) fragments derived from transfer RNAs (tRNAs), also known as tRNA fragments or tRFs. Traditionally, a miRNA genomic locus was thought to give rise to a single mature miRNA (archetype). The archetype's sequence was recorded in public databases and used to design reagents and experiments. Advances in sequencing technology have revealed that miRNA loci simultaneously give rise to multiple isomiRs, i.e. isoforms of the archetype miRNAs, with distinct endpoints and abundances. Importantly, isoforms are loaded on the RNA-induced silencing complex (RISC) thereby entering the RNA interference (RNAi) pathway where they guide sequence-based RISC interactions with specifically targeted messenger RNAs (mRNAs) and ncRNAs, thusly controlling the abundance of those transcripts. Moreover, miRNAs have been linked to a multitude of cellular processes in health and disease. Analogously, the genomic loci harboring tRNAs were thought to give rise to only the mature tRNA sequence, the latter being an integral part of the translation of mRNAs into amino acid sequences. As with isomiRs, modern sequencing technology revealed the existence of tRNA fragments that co-exist with the corresponding full-length mature tRNAs. Fast accumulating evidence has already linked tRFs to cell growth, cell proliferation, response to DNA damage, translation initiation, response to stress, etc. Some tRFs have also been found on RISC and to participate in RNAi, similarly to isomiRs. We investigated isomiRs and tRFs in human samples, in health and disease. Specifically, we used public transcriptomic datasets from the 1,000 Genomes Project and from The Cancer Genome Atlas (TCGA) repository at the National Institutes of Health. By analyzing samples from nearly five hundred healthy individuals we found that both the isomiR profiles and the tRF profiles depend on a person's gender, population, race, tissue and tissue state. In the case of tRNA fragments, we found that they derive from nuclear and from mitochondrial tRNAs. By focusing on data from cancer patients we found that the dependencies we uncovered extend to the disease context as well. In particular, our analysis of samples from White and African-American triple negative breast cancer (TNBC) patients showed that there exist extensive and significant differences in the isomiR and tRF profiles between the two races. More specifically, we identified many isomiRs and tRFs that are differentially abundant in TNBC samples from White patients vs. TNBC samples from African-American patients. We also found that analogous isomiR and tRF differences distinguish the normal breast samples of White and African American subjects. When we integrated the isomiR information with mRNA expression values from the corresponding TCGA TNBC samples we found that the molecular biology differences in the isomiR and tRF profiles were indeed reflected in the abundance of protein coding genes, a result that could serve as a starting point for deeper research activities towards explaining health disparities in this breast cancer subtype. Our studies suggest that miRNA isoforms and tRNA fragments are active novel members of the molecular biology of TNBC. Future studies of this disease will need to also consider these molecules given that they represent a component of the cell's regulatory layer that depends on the patient's race. This abstract is also presented as Poster C62. Citation Format: Aristeidis G. Telonis, Phillipe Loher, Yi Jing, Eric Londin, Isidore Rigoutsos. The molecular biology of nuclear and mitochondrial regulatory noncoding RNAs differs between white and African American patients with triple-negative breast cancer. [abstract]. In: Proceedings of the Eighth AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 13-16, 2015; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2016;25(3 Suppl):Abstract nr PR04.

Abstract 3213: Rosehip (Rosa canina) extracts prevent MAPK and AKT-mediated cell proliferation in African American triple-negative breast cancer cells

Abstract Triple Negative Breast Cancer (TNBC) is an aggressive form of breast cancer, characterized by its lack of the human epidermal growth factor receptor-2 (HER-2), the estrogen receptor (ER), and the progesterone receptor (PR). The high prevalence of triple negative tumors in young women is more commonly observed in young African American (AA) women. Currently, the existing targeted therapy is of minimal benefit in TNBCs. Akt and MAPK have been shown to promote cell proliferation in triple negative breast cancer and MAPK expression may be an underlying mechanism contributing to the generation of chemo-resistance in triple-negative breast cancer. Due to major concerns involving the occurrence of side effects and the emergence of drug-resistant cancer cells, there has been growing interest in the use of naturally occurring molecules with chemo-preventive and chemo- therapeutic properties in cancer treatment. Rosehip extracts have been used as dietary supplements to relieve symptoms associated with diarrhea, gastritis, and rheumatoid arthritis and have been shown to prevent cell proliferation in glioblastomas. This study investigated the efficacy of rosehip extracts in preventing cell proliferation in African American triple negative (HCC70, HCC1806) and luminal (HCC1500) breast cancer cell lines. Each of the breast cancer cell lines were treated with rosehip extracts (1mg/mL -25ng/mL) demonstrated a significant decrease in cell proliferation. The rosehip extract-mediated decrease in cell proliferation was equal to or better than the decrease of cell proliferation observed when known inhibitors of the MAPK (U0126, 10 μM) or AKT (LY294002, 20 μM) signaling pathways were utilized. Additionally, pretreatment of these cell lines with these Rosehip extracts (1mg/mL -25ng/mL) selectively decreased AKT, MAPK, p70S6K, and S6 phosphorylation suggesting these extracts prevent AA TNBC cell proliferation by blocking both the MAPK and AKT signaling mechanisms. Results from cell cycle analysis by flow cytometry, western blot analysis, as well as apoptosis studies demonstrate that rosehip extracts inhibit cell proliferation but do not promote apoptosis. Rosehip extracts also have a synergistic effect with Doxorubicin (20µM), a chemotherapeutic agent used to treat patients with breast cancer, in preventing triple negative breast cancer cell proliferation. Taken together these data suggest that rosehip extracts are capable of decreasing cell proliferation in African American triple negative breast cancer cells without promoting apoptosis and demonstrate a synergistic inhibition of cell proliferation with Doxorubicin, and rosehip extracts may serve as an alternative or compliment to current chemotherapeutic regimens for triple negative breast cancer. Citation Format: Patrice Cagle, Tonisha Coburn, Patrick M. Martin. Rosehip (Rosa canina) extracts prevent MAPK and AKT-mediated cell proliferation in African American triple-negative breast cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3213. doi:10.1158/1538-7445.AM2014-3213

Toll-Like Receptor-9 Expression Does not Predict for Breast Cancer Specific Outcome in African-American Triple-Negative Breast Cancer Patients

Prior research has indicated low tumor Toll-like receptor 9 (TLR9) expression is associated with worsened disease-specific survival in patients with triple-negative breast cancer (TNBC), but not hormone receptor positive (ER+, PgR+, Her-2-) breast cancer in a Finnish Caucasian population. An inverse relationship between survival and TLR-9 status has been detected in renal cell carcinoma in a similar, highly homogenous population. The aim of this study was to evaluate TLR9 expression in a population of African American TNBC patients and assess its relationship to survival and recurrence.

Triple-negative breast carcinoma in African American and Caucasian women: clinicopathology, immunomarkers, and outcome.

Breast cancers are often classified on the presence/absence of hormone receptors, and growth factor oncogenes (estrogen receptor, progesterone receptor, HER2). Triple-negative breast cancers, negative for these markers, do not benefit from targeted therapy. We compared clinicopathologic parameters and immunohistochemical markers of prognostic and/or predictive significance, and outcome between African American and Caucasian triple-negative breast cancer patients. Invasive triple-negative breast cancers from African American (n=94) and Caucasian (n=68) patients were studied. Clinicopathologic features (age, tumor size, grade, lymph node status, angiolymphatic invasion, visceral metastases) and survival (overall and progression free) were compared. Marker expression (CK5, CK7, CK8, CK14, CK18, CK19, vimentin, CD44, c-Kit, epidermal growth factor receptor, p-cadherin, p53, p63, topoisomerase II, androgen receptor, Ki-67) was assessed in tissue microarrays. Significant differences between African American and Caucasian women were observed for mean age and tumor size. African Americans had a trend toward greater lymph node involvement than Caucasians. The following markers were found in significantly different frequencies between the 2 groups: CK5, CK8, CK19, c-Kit, androgen receptor, and high Ki-67. African Americans show shorter overall and progression-free survival. Other clinicopathologic parameters, markers, and outcome were present at similar frequencies. African American triple-negative breast cancers were more aggressive, occurring at a younger age, being larger, with higher proliferation, patients more frequently dying of disease, and with a trend toward positive lymph node status. Heterogeneity of marker expression suggests variation in the genetics of breast carcinomas in different races.