Cooperation between PRMT1 and PRMT6 drives lung cancer health disparities among Black/African American men

Lung cancer is the third most common cancer with Black/AA men showing higher risk and poorer outcomes than NHW men. Lung cancer disparities are multifactorial, driven by tobacco exposure, inequities in care access, upstream health determinants, and molecular determinants including biological and genetic factors. Elevated expressions of protein arginine methyltransferases (PRMTs) correlating with poorer prognosis have been observed in many cancers. Most importantly, our study shows that PRMT6 displays higher expression in lung cancer tissues of Black/AA men compared to NHW men. In this study, we investigated the underlying mechanism of PRMT6 and its cooperation with PRMT1 to form a heteromer as a driver of lung cancer. Disrupting PRMT1/PRMT6 heteromer by a competitive peptide reduced proliferation in non-small cell lung cancer cell lines and patient-derived organoids, therefore, giving rise to a more strategic approach in the treatment of Black/AA men with lung cancer and to eliminate cancer health disparities.

Molecular Atlas of HER2+ Breast Cancer Cells Treated with Endogenous Ligands: Temporal Insights into Mechanisms of Trastuzumab Resistance

Trastuzumab therapy in HER2+ breast cancer patients has mixed success owing to acquired resistance to therapy. A detailed understanding of downstream molecular cascades resulting from trastuzumab resistance is yet to emerge. In this study, we investigate the cellular mechanisms underlying acquired resistance using trastuzumab-sensitive and -resistant cancer cells (BT474 and BT474R) treated with endogenous ligands EGF and HRG across time. We probe early receptor organization through microscopy and signaling events through multiomics measurements and assess the bioenergetic state through mitochondrial measurements. Integrative analyses of our measurements reveal significant alterations in EGF-treated BT474 HER2 membrane dynamics and robust downstream activation of PI3K/AKT/mTORC1 signaling. EGF-treated BT474R shows a sustained interferon-independent activation of the IRF1/STAT1 cascade, potentially contributing to trastuzumab resistance. Both cell lines exhibit temporally divergent metabolic demands and HIF1A-mediated stress responses. BT474R demonstrates inherently increased mitochondrial activity. HRG treatment in BT474R leads to a pronounced reduction in AR expression, affecting downstream lipid metabolism with implications for treatment response. Our results provide novel insights into mechanistic changes underlying ligand treatment in BT474 and BT474R and emphasize the pivotal role of endogenous ligands. These results can serve as a framework for furthering the understanding of trastuzumab resistance, with therapeutic implications for women with acquired resistance.

Arginine regulates HSPA5/BiP translation through ribosome pausing in triple-negative breast cancer cells

BACKGROUND

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with a high mortality rate due to a lack of therapeutic targets. Many TNBC cells are reliant on extracellular arginine for survival and express high levels of binding immunoglobin protein (BiP), a marker of metastasis and endoplasmic reticulum (ER) stress response.

METHODS

In this study, the effect of arginine shortage on BiP expression in the TNBC cell line MDA-MB-231 was evaluated. Two stable cell lines were generated in MDA-MB-231 cells: the first expressed wild-type BiP, and the second expressed a mutated BiP free of the two arginine pause-site codons, CCU and CGU, termed G-BiP.

RESULTS

The results showed that arginine shortage induced a non-canonical ER stress response by inhibiting BiP translation via ribosome pausing. Overexpression of G-BiP in MDA-MB-231 cells promoted cell resistance to arginine shortage compared to cells overexpressing wild-type BiP. Additionally, limiting arginine led to decreased levels of the spliced XBP1 in the G-BiP overexpressing cells, potentially contributing to their improved survival compared to the parental WT BiP overexpressing cells.

CONCLUSION

In conclusion, these findings suggest that the downregulation of BiP disrupts proteostasis during arginine shortage-induced non-canonical ER stress and plays a key role in cell growth inhibition, indicating BiP as a target of codon-specific ribosome pausing upon arginine shortage.

Molecular features of androgen-receptor low, estrogen receptor-negative breast cancers in the Carolina breast cancer study

PURPOSE

Androgen receptor (AR) expression is absent in 40-90% of estrogen receptor (ER)-negative breast cancers. The prognostic value of AR in ER-negative patients and therapeutic targets for patients absent in AR remains poorly explored.

METHODS

We used an RNA-based multigene classifier to identify AR-low and AR-high ER-negative participants in the Carolina Breast Cancer Study (CBCS; N = 669) and The Cancer Genome Atlas (TCGA; N = 237). We compared AR-defined subgroups by demographics, tumor characteristics, and established molecular signatures [PAM50 risk of recurrence (ROR), homologous recombination deficiency (HRD), and immune response].

RESULTS

AR-low tumors were more prevalent among younger (RFD =  + 10%, 95% CI = 4% to 16%) participants in CBCS and were associated with HER2 negativity (RFD = - 35%, 95% CI = - 44% to - 26%), higher grade (RFD =  + 17%, 95% CI = 8% to 26%), and higher risk of recurrence scores (RFD =  + 22%, 95% CI = 16.1% to 28%), with similar results in TCGA. The AR-low subgroup was strongly associated with HRD in CBCS (RFD =  + 33.3%, 95% CI = 23.8% to 43.2%) and TCGA (RFD =  + 41.5%, 95% CI = 34.0% to 48.6%). In CBCS, AR-low tumors had high adaptive immune marker expression.

CONCLUSION

Multigene, RNA-based low AR expression is associated with aggressive disease characteristics as well as DNA repair defects and immune phenotypes, suggesting plausible precision therapies for AR-low, ER-negative patients.

Does the Vaginal Microbiome Operate Differently by Race to Influence Risk of Precervical Cancer?

Background: The vaginal microbiome (VMB) plays an important role in the persistence of human papillomavirus (HPV) infection and differs by race and among women with cervical intraepithelial neoplasia (CIN). Materials and Methods: We explored these relationships using 16S rRNA VMB taxonomic profiles of 3050 predominantly Black women. VMB profiles were assigned to three subgroups based on taxonomic markers indicative of vaginal wellness: optimal (Lactobacillus crispatus, L. gasseri, and L. jensenii), moderate (L. iners), and suboptimal (Gardnerella vaginalis, Atopobium vaginae, Ca. Lachnocurva vaginae, and others). Multivariable Firth logistic regression models were adjusted for age, smoking, VMB, HPV, and pregnancy status. Results: VMB prevalence by subgroup was 18%, 30%, and 51% for the optimal, moderate, and suboptimal groups, respectively. In fully adjusted models, the risk of CIN grade 3 (CIN3) among non-Latina (nL) Blacks was twice that of nL Whites (odds ratio [OR] = 2.0, 95% confidence interval [CI]: 1.1, 3.9, p = 0.02). The VMB modified this association (p = 0.04) such that the risk of CIN3 was significantly higher for nL Blacks than for nL Whites only among women with optimal VMBs (OR = 7.8, 95% CI: 1.7, 74.5, p = 0.007). Within racial groups, the risk of CIN3 was only elevated among nL White women with suboptimal VMBs (OR = 6.0, 95% CI: 1.3, 56.9, p = 0.02) compared with their racial counterparts with optimal VMBs. Conclusions: Our findings suggest that race is a modifier of the VMB in HPV carcinogenesis. An optimal VMB does not appear to be protective for nL Black women compared with nL White women.

Abstract 72: Ablation of WNT10B alters the tumor microenvironment in highly metastatic breast cancer, altering paclitaxel response

Triple-negative breast cancer (TNBC) has the worst survival outcome and the greatest incidence of metastasis among breast cancer subtypes. We have shown that the WNT10B network, composed of β-CATENIN, HMGA2, and EZH2, is predictive of higher rates of TNBC metastasis and poorer overall survival in TNBC. The stroma-tumor microenvironment (TME) interactions in metastatic breast cancer remain poorly defined, and prior to our work, the role of WNT10B signaling in the TME was unknown. Global gene expression profiling of the Wnt10bKO total mammary glands demonstrated a gene signature consistent with altered metabolism and markers promoting adipocyte differentiation. Wnt10b ablation in the mammary gland increases adipogenic differentiation and decreases the number of mammary gland terminal-end buds, and epithelia to stroma/fibroblast cell ratios. Therefore, we questioned the role of WNT10B in stromal cancer-associated fibroblast (CAFs) and cancer-associated adipocytes (CAAs) in the TME of transformed mammary glands. By backcrossing our Wnt10bKO mice to the highly metastatic MMTV-PyMT (PyMT) transgenic mammary tumor model, we demonstrated alteration in the age of tumor onset, changes in the incidence of transformation of thoracic and abdominal-inguinal tumors, and impacts on survival rates. Moreover, adipogenic markers are higher and persist through transformation in PyMTWnt10bKO mice compared to PyMT mice. Proliferation, migration, and invasion are also impacted in the PyMTWnt10bKO CAFs when co-cultured with PyMT tumor cells. The ability of PyMTWnt10bKO CAFs to alter cellular plasticity and generate CAAs is higher than PyMT CAFs. Additionally, PyMTWnt10bKO CAFs lose expression of canonical Wnt markers DVL and LRP and gain non-canonical Wnt signaling via WNT5B/ROR pathways that persist in the KO CAAs. We also observed alterations in chemoresistance in KO tumor epithelium. The resistance to paclitaxel from enriched PyMT epithelia from thoracic tumors was higher than epithelia enriched from the abdominal-inguinal tumors. Interestingly, the Wnt10bKO TME inverted the response to paclitaxel and the abdominal-inguinal epithelial tumor cells were more resistant than those from the thoracic epithelium. Furthermore, resistance to paclitaxel was associated with higher responses to PRI-724, a CBP-β-CATENIN inhibitor. Neither WT nor KO epithelial subtypes were resistant to olaparib exposure. Therefore, we conclude that Wnt10b is essential to educate highly metastatic breast cancer stromal cells to promote growth, metastatic colonization, and resistance to paclitaxel.

Citation Format: Hannah R. Kelso, Rachel S. Perkins, Ikbale El Ayachi, Jackelyn A. Alva-Ornelas, Tiffany N. Seagroves, Victoria L. Seewaldt, Susan A. Krum, Gustavo Adolfo Miranda-Carboni. Ablation of WNT10B alters the tumor microenvironment in highly metastatic breast cancer, altering paclitaxel response [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 72.

Disparities in the use of screening breast magnetic resonance imaging persist in Louisiana after the Affordable Care Act: A question of access, policy, institutional support, or something else?

BACKGROUND

Louisiana continues to have one of the highest breast cancer mortality rates in the nation, and Black women are disproportionally affected. Louisiana has made advances in improving access to breast cancer screening through the expansion of Medicaid. There remains, however, broad underuse of advanced imaging technology such as screening breast magnetic resonance imaging (MRI), particularly for Black women.

METHODS

Breast MRI has been proven to be very sensitive for the early detection of breast cancer in women at high risk. MRI is more sensitive than mammography for aggressive, invasive breast cancer types, which disproportionally affect Black women. Here the authors identify potential barriers to breast MRI screening in Black women, propose strategies to address disparities in access, and advocate for specific recommendations for change.

RESULTS

Cost was identified as one of the greatest barriers to screening breast MRI. The authors propose implementation of cost-saving, abbreviated protocols to address cost along with lobbying for further expansion of the Affordable Care Act (ACA) to include coverage for screening breast MRI. In addition, addressing gaps in communication and knowledge and facilitating providers' ability to readily identify women who might benefit from MRI could be particularly impactful for high-risk Black women in Louisiana communities.

CONCLUSIONS

Since the adoption of the ACA in Louisiana, Black women have continued to have disproportionally high breast cancer mortality rates. This persistent disparity provides evidence that additional change is needed. This change should include exploring innovative ways to make advanced imaging technology such as breast MRI more accessible and expanding research to specifically address community and culturally specific barriers.

Molecular Assessment of HER2 to Identify Signatures Associated with Therapy Response in HER2-Positive Breast Cancer

Simple Summary

The HER2 status of breast cancers is accurately determined by measuring HER2 protein overexpression and gene amplification. However, these clinical diagnostic tests cannot predict the response to therapy. Single molecule imaging approaches can quantify molecular features of HER2, such as receptor nano-organization, with exquisite spatial resolution and sensitivity. The aim of our study was to assess how the molecular features of HER2 varied with the therapy response. According to our results in cultured cell lines and six patient specimens, the therapy response was associated with high detected HER2 densities and clustering. This advanced imaging approach can thus provide key data to complement the current diagnostic standards.

Abstract

Trastuzumab, the prototype HER2-directed therapy, has markedly improved survival for women with HER2-positive breast cancers. However, only 40–60% of women with HER2-positive breast cancers achieve a complete pathological response to chemotherapy combined with HER2-directed therapy. The current diagnostic assays have poor positive-predictive accuracy in identifying therapy-responsive breast cancers. Here, we deployed quantitative single molecule localization microscopy to assess the molecular features of HER2 in a therapy-responsive setting. Using fluorescently labeled trastuzumab as a probe, we first compared the molecular features of HER2 in trastuzumab-sensitive (BT-474 and SK-BR-3) and trastuzumab-resistant (BT-474^R and JIMT-1) cultured cell lines. Trastuzumab-sensitive cells had significantly higher detected HER2 densities and clustering. We then evaluated HER2 in pre-treatment core biopsies from women with breast cancer undergoing neoadjuvant therapy. A complete pathological response was associated with a high detected HER2 density and significant HER2 clustering. These results established the nano-organization of HER2 as a potential signature of therapy-responsive disease.

Understanding drivers of the Black:White breast cancer mortality gap: A call for more robust definitions

Kim et al completed a pooled analysis of 8 National Surgical Adjuvant Breast and Bowel Project trials and highlight that, when compared with White patients, Black patients with estrogen receptor–positive (ER+) breast cancer have worse distant recurrence‐free survival, especially in the setting of neoadjuvant chemotherapy when pathologic complete response is not achieved. This editorial highlights that, to comprehend the drivers of this disparity, we must have more robust definitions of ER+ breast cancer and race.

Impact of Federal, State, and Local Housing Policies on Disparities in Cardiovascular Disease in Black/African American Men and Women: From Policy to Pathways to Biology

Racist and discriminatory federal, state, and local housing policies significantly contribute to disparities in cardiovascular disease incidence and mortality for individuals that self-identify as Black or African American. Here we highlight three key housing policies - "redlining," zoning, and the construction of highways - which have wrought a powerful, sustained, and destructive impact on cardiovascular health in Black/African American communities. Redlining and highway construction policies have restricted access to quality health care, increased exposure to carcinogens such as PM_2.5, and increased exposure to extreme heat. At the root of these policy decisions are longstanding, toxic societal factors including racism, segregation, and discrimination, which also serve to perpetuate racial inequities in cardiovascular health. Here, we review these societal and structural factors and then link them with biological processes such as telomere shortening, allostatic load, oxidative stress, and tissue inflammation. Lastly, we focus on the impact of inflammation on the immune system and the molecular mechanisms by which the inflamed immune microenvironment promotes the formation of atherosclerotic plaques. We propose that racial residential segregation and discrimination increases tissue inflammation and cytokine production, resulting in dysregulated immune signaling, which promotes plaque formation and cardiovascular disease. This framework has the power to link structural racism not only to cardiovascular disease, but also to cancer.

Vascularity and Dynamic Contrast-Enhanced Breast Magnetic Resonance Imaging

Angiogenesis is a key step in the initiation and progression of an invasive breast cancer. High microvessel density by morphological characterization predicts metastasis and poor survival in women with invasive breast cancers. However, morphologic characterization is subject to variability and only can evaluate a limited portion of an invasive breast cancer. Consequently, breast Magnetic Resonance Imaging (MRI) is currently being evaluated to assess vascularity. Recently, through the new field of radiomics, dynamic contrast enhanced (DCE)-MRI is being used to evaluate vascular density, vascular morphology, and detection of aggressive breast cancer biology. While DCE-MRI is a highly sensitive tool, there are specific features that limit computational evaluation of blood vessels. These include (1) DCE-MRI evaluates gadolinium contrast and does not directly evaluate biology, (2) the resolution of DCE-MRI is insufficient for imaging small blood vessels, and (3) DCE-MRI images are very difficult to co-register. Here we review computational approaches for detection and analysis of blood vessels in DCE-MRI images and present some of the strategies we have developed for co-registry of DCE-MRI images and early detection of vascularization.

Epigenetic Dysregulation of KCNK9 Imprinting and Triple-Negative Breast Cancer

Simple Summary

Genomic imprinting is an inherited form of parent-of-origin specific epigenetic gene regulation that is dysregulated by poor prenatal nutrition and environmental toxins. Here, we showed that KCNK9 is imprinted in breast tissue and identified the differentially methylated region (DMR) controlling its imprint status. Hypomethylation at the DMR, coupled with biallelic expression of KCNK9, occurred in 63% of triple-negative breast cancers (TNBC). The association between hypomethylation and TNBC status was highly significant in African-Americans (p = 0.006), but not in Caucasians (p = 0.70). The high frequency of KCNK9 DMR hypomethylation in TNBC and non-cancerous breast tissue from high-risk women provides evidence that hypomethylation of the KNCK9 DMR/TASK3 overexpression may provide a new target for prevention of TNBC.

Abstract

Genomic imprinting is an inherited form of parent-of-origin specific epigenetic gene regulation that is dysregulated by poor prenatal nutrition and environmental toxins. KCNK9 encodes for TASK3, a pH-regulated potassium channel membrane protein that is overexpressed in 40% of breast cancer. However, KCNK9 gene amplification accounts for increased expression in <10% of these breast cancers. Here, we showed that KCNK9 is imprinted in breast tissue and identified a differentially methylated region (DMR) controlling its imprint status. Hypomethylation at the DMR, coupled with biallelic expression of KCNK9, occurred in 63% of triple-negative breast cancers (TNBC). The association between hypomethylation and TNBC status was highly significant in African-Americans (p = 0.006), but not in Caucasians (p = 0.70). KCNK9 hypomethylation was also found in non-cancerous tissue from 77% of women at high-risk of developing breast cancer. Functional studies demonstrated that the KCNK9 gene product, TASK3, regulates mitochondrial membrane potential and apoptosis-sensitivity. In TNBC cells and non-cancerous mammary epithelial cells from high-risk women, hypomethylation of the KCNK9 DMR predicts for increased TASK3 expression and mitochondrial membrane potential (p < 0.001). This is the first identification of the KCNK9 DMR in mammary epithelial cells and demonstration that its hypomethylation in breast cancer is associated with increases in both mitochondrial membrane potential and apoptosis resistance. The high frequency of hypomethylation of the KCNK9 DMR in TNBC and non-cancerous breast tissue from high-risk women provides evidence that hypomethylation of the KNCK9 DMR/TASK3 overexpression may serve as a marker of risk and a target for prevention of TNBC, particularly in African American women.

Changes in Immune Cell Types with Age in Breast are Consistent with a Decline in Immune Surveillance and Increased Immunosuppression

A majority of breast cancers (BC) are age-related and we seek to determine what cellular and molecular changes occur in breast tissue with age that make women more susceptible to cancer initiation. Immune-epithelial cell interactions are important during mammary gland development and the immune system plays an important role in BC progression. The composition of human immune cell populations is known to change in peripheral blood with age and in breast tissue during BC progression. Less is known about changes in immune populations in normal breast tissue and how their interactions with mammary epithelia change with age. We quantified densities of T cells, B cells, and macrophage subsets in pathologically normal breast tissue from 122 different women who ranged in age from 24 to 74 years old. Donor-matched peripheral blood from a subset of 20 donors was analyzed by flow cytometry. Tissue immune cell densities and localizations relative to the epithelium were quantified in situ with machine learning-based image analyses of multiplex immunohistochemistry-stained tissue sections. In situ results were corroborated with flow cytometry analyses of peri-epithelial immune cells from primary breast tissue preparations and transcriptome analyses of public data from bulk tissue reduction mammoplasties. Proportions of immune cell subsets in breast tissue and donor-matched peripheral blood were not correlated. Density (cells/mm²) of T and B lymphocytes in situ decreased with age. T cells and macrophages preferentially localized near or within epithelial bilayers, rather than the intralobular stroma. M2 macrophage density was higher than M1 macrophage density and this difference was due to higher density of M2 in the intralobular stroma. Transcriptional signature analyses suggested age-dependent decline in adaptive immune cell populations and functions and increased innate immune cell activity. T cells and macrophages are so intimately associated with the epithelia that they are embedded within the bilayer, suggesting an important role for immune-epithelial cell interactions. Age-associated decreased T cell density in peri-epithelial regions, and increased M2 macrophage density in intralobular stroma suggests the emergence of a tissue microenvironment that is simultaneously immune-senescent and immunosuppressive with age.

The Association between Polluted Neighborhoods and TP53-Mutated Non-Small Cell Lung Cancer

BACKGROUND

Poor patients often reside in neighborhoods of lower socioeconomic status (SES) with high levels of airborne pollutants. They also have higher mortality from non-small cell lung cancer (NSCLC) than those living in wealthier communities. We investigated whether living in polluted neighborhoods is associated with somatic mutations linked with lower survival rates, i.e., TP53 mutations.

METHODS

In a retrospective cohort of 478 patients with NSCLC treated at a comprehensive cancer center between 2015 and 2018, we used logistic regression to assess associations between individual demographic and clinical characteristics, including somatic TP53 mutation status and environmental risk factors of annual average particulate matter (PM2.5) levels, and neighborhood SES.

RESULTS

277 patients (58%) had somatic TP53 mutations. Of those, 45% lived in neighborhoods with "moderate" Environmental Protection Agency-defined PM2.5 exposure, compared with 39% of patients without TP53 mutations. We found significant associations between living in neighborhoods with "moderate" versus "good" PM2.5 concentrations and minority population percentage [OR, 1.06; 95% confidence interval (CI), 1.04-1.08]. There was a significant association between presence of TP53 mutations and PM2.5 exposure (moderate versus good: OR, 1.66; 95% CI, 1.02-2.72) after adjusting for patient characteristics, other environmental factors, and neighborhood-level SES.

CONCLUSIONS

When controlling for individual- and neighborhood-level confounders, we find that the odds of having a TP53-mutated NSCLC are increased in areas with higher PM2.5 exposure.

IMPACT

The link between pollution and aggressive biology may contribute to the increased burden of adverse NSCLC outcomes in individuals living in lower SES neighborhoods.

Breast-Specific Molecular Clocks Comprised of ELF5 Expression and Promoter Methylation Identify Individuals Susceptible to Cancer Initiation

A robust breast cancer prevention strategy requires risk assessment biomarkers for early detection. We show that expression of ELF5, a transcription factor critical for normal mammary development, is downregulated in mammary luminal epithelia with age. DNA methylation of the ELF5 promoter is negatively correlated with expression in an age-dependent manner. Both ELF5 methylation and gene expression were used to build biological clocks to estimate chronological ages of mammary epithelia. ELF5 clock-based estimates of biological age in luminal epithelia from average-risk women were within three years of chronological age. Biological ages of breast epithelia from BRCA1 or BRCA2 mutation carriers, who were high risk for developing breast cancer, suggested they were accelerated by two decades relative to chronological age. The ELF5 DNA methylation clock had better performance at predicting biological age in luminal epithelial cells as compared with two other epigenetic clocks based on whole tissues. We propose that the changes in ELF5 expression or ELF5-proximal DNA methylation in luminal epithelia are emergent properties of at-risk breast tissue and constitute breast-specific biological clocks. PREVENTION RELEVANCE: ELF5 expression or DNA methylation level at the ELF5 promoter region can be used as breast-specific biological clocks to identify women at higher than average risk of breast cancer.

Boosting immune surveillance by low-dose PI3K inhibitor facilitates early intervention of breast cancer

Prevention of estrogen receptor-negative (ER-) breast cancer is an unmet challenge, although tamoxifen and aromatase inhibitors can successfully decrease the incidence of ER-positive (ER+) breast cancer. PI3K pathway activation has been detected in tamoxifen-resistant ER- breast lesions of patients. Here, we further ratified that the PI3K pathway is significantly activated in premalignant ER- breast lesions compared with paired normal tissues of patients, which prompted our assessment of targeting PI3K on inhibition of ER- mammary tumor initiation and progression. Both genetic knockdown of PIK3CA or intervention with low-doses of a PI3K inhibitor (GDC-0941) prevented the dysplasia phenotype of semi-transformed human ER- mammary epithelial cells in 3-dimensional culture in vitro. Importantly, low-dose GDC-0941 treatment significantly delayed mammary tumor initiation in the MMTV-neu mouse model without exhibiting discernable adverse effects. Interestingly, increased CD8⁺/GZMB⁺ T-cells were detected in mammary tissue after GDC-0941 treatment, suggesting enhanced immune surveillance. Mechanistically, elevated expression of potent T-cell chemo-attractants, including CCL5 and CXCL10, were detected both in vitro and in vivo after GDC-0941 treatment. Furthermore, inhibition of PI3K significantly increased T-cell recruitment in a CCL5/CXCL10-dependent manner. In human ER- breast cancer, PI3K activation is correlated with significantly reduced CCL5, CXCL10 and CD8A expression, suggesting that the decreased CD8⁺ T-cell recruitment and escape of immune surveillance may contribute to ER- breast cancer development. In summary, our study indicates that low-dose PI3K inhibitor treatment may intervene early stage ER- breast cancer development by enhancing immune surveillance via CCL5/CXCL10.

Metformin and Chemoprevention: Potential for Heart-Healthy Targeting of Biologically Aggressive Breast Cancer

Currently, tamoxifen is the only drug approved for reduction of breast cancer risk in premenopausal women. The significant cardiovascular side effects of tamoxifen, coupled with lack of a survival benefit, potential for genotoxicity, and failure to provide a significant risk-reduction for estrogen receptor-negative breast cancer, all contribute to the low acceptance of tamoxifen chemoprevention in premenopausal women at high-risk for breast cancer. While other prevention options exist for postmenopausal women, there is a search for well-tolerated prevention agents that can simultaneously reduce risk of breast cancers, cardiovascular disease, and type-2 diabetes. Metformin is a well-tolerated oral biguanide hypoglycemic agent that is prescribed worldwide to over 120 million individuals with type-2 diabetes. Metformin is inexpensive, safe during pregnancy, and the combination of metformin, healthy lifestyle, and exercise has been shown to be effective in preventing diabetes. There is a growing awareness that prevention drugs and interventions should make the “whole woman healthy.” To this end, current efforts have focused on finding low toxicity alternatives, particularly repurposed drugs for chemoprevention of breast cancer, including metformin. Metformin's mechanisms of actions are complex but clearly involve secondary lowering of circulating insulin. Signaling pathways activated by insulin also drive biologically aggressive breast cancer and predict poor survival in women with breast cancer. The mechanistic rationale for metformin chemoprevention is well-supported by the scientific literature. Metformin is cheap, safe during pregnancy, and has the potential to provide heart-healthy breast cancer prevention. On-going primary and secondary prevention trials will provide evidence whether metformin is effective in preventing breast cancer.

Spatiotemporal strategies to identify aggressive biology in precancerous breast biopsies

Over 90% of breast cancer is cured; yet there remain highly aggressive breast cancers that develop rapidly and are extremely difficult to treat, much less prevent. Breast cancers that rapidly develop between breast image screening are called “interval cancers.” The efforts of our team focus on identifying multiscale integrated strategies to identify biologically aggressive precancerous breast lesions. Our goal is to identify spatiotemporal changes that occur prior to development of interval breast cancers. To accomplish this requires integration of new technology. Our team has the ability to perform single cell in situ transcriptional profiling, noncontrast biological imaging, mathematical analysis, and nanoscale evaluation of receptor organization and signaling. These technological innovations allow us to start to identify multidimensional spatial and temporal relationships that drive the transition from biologically aggressive precancer to biologically aggressive interval breast cancer.

This article is categorized under:

Cancer > Computational Models

Cancer > Molecular and Cellular Physiology

Cancer > Genetics/Genomics/Epigenetics

Abstract A082: Influencing women's attitudes toward participation in breast cancer clinical research: Improving inclusion of women of color

The United States is increasingly racially and ethnically diverse. In fact, California is now a majority-minority region, with a greater percentage of its population comprised of racial minorities than whites. Yet, minorities are continually under-represented in clinical research trials, which provide crucial information on which the future of cancer treatments is built. Without representative inclusion of participants of color in clinical research, we cannot develop effective preventative and treatment approaches for everyone. This current study investigates the factors, including characteristics of study consenters, that may influence women—particularly women of color (WOC)—to accept or decline participation in breast cancer-related trials. We assess these factors through a brief survey, administered to patients immediately after they were invited to participate in a breast cancer-related clinical study. From the beginning of study accrual to the present, twenty-three patients have taken the survey. We anticipate accruing 200 participants at a rate of 25 per month. For the preliminary analyses, we split participants in two groups: white women (WW) (n = 14) and women of color (WOC) (n = 9). We conducted independent sample t-tests to compare the responses of WW and WOC. More WOC (M = 1.44, SD = 0.73) reported that it is important that their consenter is of the same ethnicity or race than WW (M = 1.00, SD = .00), t (21) = -2.32, p &lt; .05. Similarly, WOC (M = 1.44, SD = .73) also reported that it is important that the person inviting them to participate in research look like people in their community, compared to the importance placed on this factor by WW (M = 1.00, SD = .00), t (21) = -2.32, p &lt; .05). More WOC (M = 2.33, SD = 1.23) also cited “feeling overwhelmed” with their medical condition as influential in their decision to participate in clinical research than WW (M = 1.31, SD = .48), t (20) = -2.75, p &lt; .05. Although both groups positively rated their interaction with the consenter, we observed marginal differences between WOC and WW. WOC (M = 7.00, SD = .00) gave higher ratings to the variable of “consenter created an atmosphere of trust and support” compared to ratings given by WW (M = 6.29, SD = 1.07), t (21) = -1.99, p = .06. Though participants are generally satisfied with their consenter interaction, different factors influence WW and WOC as they decide whether to participate in clinical research. When identified, these factors can be used to inform more inclusive consenting processes.

Citation Format: Noe R. Chavez, Alan Nunez, Angela K. Wong, Tanya A. Chavez, Ellen Rippberger, Christine Thai, Angelica Sanchez, Ombeni M. Idassi, Krista M. Round, Kendall Kennedy, Margarita Robles, Jackelyn A. Alva-Ornelas, Jerneja Tomsic, Chidimma M.K. Kalu, Laura L. Kruper, Veronica C. Jones, Sharon Clancy, Amy C. Polverini, Courtney Vito, Karen Harold, Terry Hyslop, Carola M. Zalles, Daniel B. Schmolze, Christopher Sistrunk, Victoria L. Seewaldt. Influencing women's attitudes toward participation in breast cancer clinical research: Improving inclusion of women of color [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 A082.

Abstract A084: The forgotten race: Under-representation of Asians in clinical research

The United States (US) is racially and culturally diverse. Still, white women disproportionately comprise clinical trial participants, stemming largely from the fact that minorities often decline participation. Clinical trial findings, therefore, have not been representative of the diverse patient population, and have stymied progress in precision medicine and cancer prevention. According to the CDC, among Asian/Pacific Islander females, the leading cause of death is cancer. Moreover, they have more total cancer-related deaths than any other racial group. Per the 2017 US Census, Asians are the third largest minority group of the population (6.6%). Despite the grave health disparities faced by a sizable proportion of the population, the literature is sparse with regards to their research engagement. For example, several studies have focused on Black and Hispanic consenting rates, including one study that demonstrated no significant differences between the two groups (Wendler, Kington, Madans, Wye, Christ-Schmidt, Pratt et al., 2005) and another that indicated relatively lower enrollment rates among Hispanics and Blacks (Murthy, Krumholz, Gross, 2004). This gap in research is largely due to the marked heterogeneity with respect to language, nationality, and acculturation status. We examined Asian participation in three therapeutic, noninterventional trials that aim to develop early detection methods and accurate prognosis in women at high risk for breast cancer. Primarily, we collect leftover tissue and/or cells from fine needle aspirations (FNA) to better understand the cellular microenvironment that correlates with breast cancer development. We analyzed demographic data across these studies to investigate refusal rates among Asian women. Across the three trials, 3,119 participants were screened. Of the total number screened, 426 participants were eligible, 368 consented, and 58 declined. Of those who declined, 23.5% were Asians, 13.9% Hispanic, 8.3% Blacks, 5.6% Native Americans, and 11.4% White/non-Hispanic. Notably, Asians had the highest refusal rate. Fisher's exact test (two-tailed) was conducted to examine refusal rates for Asians compared to Whites, Blacks, and Hispanics. Results suggest that Asians had significantly higher rates of compared to Whites (p = .02, observed odds ratio = .42, 95% CI [.20, .86]), but were not significantly different than Blacks or Hispanics. The under-representation of Asians in research may exacerbate health disparities. Thus, further studies should examine ways, such as increasing racial and cultural competency, for increasing Asian representation in clinical research studies. Ultimately, we believe that illuminating under-representation of the “forgotten” Asian population in clinical research can inform future interventions that promote chemoprevention and treatment of this high-risk population.

Citation Format: Stacey N. Doan, Christine Thai, Angela K. Wong, Tanya A. Chavez, Angelica Sanchez, Laura L. Kruper, Veronica C. Jones, Sharon Clancy, Amy C. Polverini, Lisa D. Yee, Courtney Vito, Alan Nunez, Ellen J. Rippberger, Noe R. Chavez, Karen Herold, Chidimma M.K. Kalu, Jackelyn A. Alva-Ornelas, Jerneja Tomsic, Krista M. Round, Margarita Robles, Ombeni M. Idassi, Kendall J. Kennedy, Christopher Sistrunk, Victoria L. Seewaldt. The forgotten race: Under-representation of Asians in clinical research [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 A084.

Abstract B109: Architecture of increased breast cancer risk

Purpose: To highlight the importance of building a high-risk breast cancer clinic for women who do not have a BRCA 1, BRCA 2 or other highly penetrant cancer susceptibility mutation.

Background: Breast cancer is the most common cancer in women and the second most prevalent cause of cancer death of women in the United States; the lifetime risk for breast cancer in women is approximately 12%. Women may be at increased risk for breast cancer for many reasons including family history, genetic alterations, age, reproductive status and menstrual history. Most women who are at increased risk of developing breast cancer do not have a BRCA 1, BRCA 2 or other mutation. The majority of breast cancer diagnoses are due to acquired somatic mutations; only 5 to 10% of breast cancer diagnoses are attributable to highly penetrant Mendelian cancer susceptibility genes. White women with Ashkenazi Jewish ancestry tend to have a higher incidence of BRCA 1 and 2 mutations; traditionally, most research efforts about highly penetrant genes have been focused on this group rather than other racial and ethnic groups. However, there is a great need to study breast cancer risk-reduction strategies in racial and ethnic minorities in the United States, particularly because most breast cancers are not caused by BRCA 1 and 2 mutations. City of Hope is located approximately 21 miles northeast of Los Angeles and operates 13 clinical practice locations including Los Angeles, Orange, Riverside, San Bernardino and Ventura counties. These five counties are home to the majority of California's multicultural and ethnic residents where San Bernardino County has the highest percentage of Hispanics (49.9%) and blacks (8.3%), Ventura County has the highest percentage of whites (48.1%), and Orange County has the highest concentration of Asians (18.2%). It has been established in the literature that the greatest benefit from breast cancer prevention strategies comes from treating women who are at high risk of the disease. While it is important to build a high-risk breast cancer clinic for women with genetic mutations, it is equally important to build a high-risk breast clinic for women who are at increased risk of breast cancer but do not have a mutation, particularly because most breast cancer is diagnosed in this population. In addition, it is crucial to educate high-risk patients that although they may have tested negative for a genetic mutation if they have a family history of breast cancer, they warrant close clinical surveillance.

Methods: We are proposing a retrospective, descriptive study of data that will be collected as part of a high-risk breast cancer program implemented by City of Hope.

Results/Conclusions: We expect to discuss the findings related to serving women of all races and ethnicities who do not have a mutation in a highly penetrant gene mutation.

Citation Format: Karen Herold, Lisa D. Yee, Chidimma M. Kalu, Laura L. Kruper, Veronica C. Jones, Amy C. Polverini, Sharon Clancy, Tanya A. Chavez, Jackelyn A. Alva-Ornelas, Noe R Chavez, Ellen J. Rippberger, Jerneja Tomsic, Christopher Sistrunk, Ombeni Idassi, Daniel B. Schmolze, Courtney Vito, Alan Nunez, Angela K. Wong, Krista M. Round, Christine Thai, Angelica Sanchez, Margarita Robles, Kendall Kennedy, Terry Hyslop, Victoria L. Seewaldt. Architecture of increased breast cancer risk [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 B109.

Abstract A083: Diversifying breast cancer clinical trial accrual: An approach to recruitment at a Comprehensive Cancer Center

Background: Breast cancer (BC) prevention clinical trials (CTs) play a vital role in the progress of preventative measures and treatments for all races and ethnicities. However, Northern European whites (NE/W) continue to be disproportionally enrolled (e.g., 93.5% were non-Hispanic white in the STAR trial), while minorities such as Asians, blacks, Latinas, and Native Americans (NA) lag in participation. Current studies suggest that minorities are not approached as frequently as NE/W; however, they are just as willing to participate. Here we present a successful recruitment strategy to improving minority accrual in CTs at a Comprehensive Cancer Center located in Duarte, CA.

Method: Results from community focus groups suggested the need to mentor local youth who strive to pursue a career in the medical field. Consequently, from February 2016 to July 2018, four bilingual, bicultural clinical research assistants (CRAs) were recruited from the catchment area of City of Hope (CoH). The CRAs, in collaboration with seven surgeons, two radiologists, and one medical oncologist, led the recruitment for three nontherapeutic BC prevention CTs at CoH.

Results: All four CRAs were 1) first-generation American, 2) fluent in Spanish or Vietnamese, 3) born and raised in Southern California, and 4) pre-health. Of the 3,148 patients who were screened, 398 were eligible for enrollment, 369 consented, and 58 declined. Primary languages and races/ethnicities of those who declined include the following: 7% Armenian, 9% Chinese, 78% English, 2% Thai, and 5% Spanish; 28% Asian, 3% black, 28% Latina, 2% NA, and 67% white (22% NE, 17% Middle Eastern/North African). Demographics of the consenting population include the following: primary language - &gt;1% Armenian, 4% Chinese, 89% English, &gt;1% Korean, and 7% Spanish; race/ethnicity - 14% Asian, 6% black, 30% Latina, 5% NA, and 75% white (40% NE). Of the white population (n = 277), 11% were Middle Eastern/North African, 53% NE, and 36% Latina. Accrual surpassed both the CoH catchment area (11.3% Asian, 8% black, 24% Hispanic, 1% NA, and 32% NE/W) and the CoH interventional/nontherapeutic CT population (10% Asian/Pacific Islander, 4% black, 21% Hispanic, &gt;1% NA, and 55% NE/W).

Conclusion: Contrary to current accrual of CTs, here we show that minorities can have a large representation in CT accrual, as long as they are provided the opportunity. Accrual of Asians, Latinas, and NAs exceeded the catchment area and accrual of other CoH CTs. Interestingly, Chinese-speaking women comprised the highest declination group of the non-English speakers, and Asians and Latinas declined the most outside of non-whites. Cultural competency and bilingualism appear to be characteristics of a CRA that may help in accruing minority women into CTs. Our findings suggest that they are just as willing to participate, and the first step is to simply ask.

Citation Format: Tanya A. Chavez, Christine Thai, Angelica Sanchez, Laura L. Kruper, Veronica C. Jones, Sharon Clancy, Amy C. Polverini, Lisa D. Yee, Courtney A. Vito, Noé R. Chávez, Alan Nuñez, Ellen J. Rippberger, Angela K. Wong, Karen Herold, Chidimma M.K. Kalu, Jackelyn A. Alva-Ornelas, Jerneja Tomsic, Krista M. Round, Margarita Robles, Ombeni Idassi, Kendall J. Kennedy, Terry Hyslop, Carola M. Zalles, Christopher Sistrunk, Victoria L. Seewaldt. Diversifying breast cancer clinical trial accrual: An approach to recruitment at a Comprehensive Cancer Center [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 A083.

Abstract B119: Receptiveness of metformin as a breast cancer prevention drug within the Hispanic community

Despite cancer being the leading cause of death across most racial/ethnic groups, Hispanic women have the second highest mortality rate attributed to diabetes (4.7%) according to the Centers for Disease Control and Prevention (CDC). While cancer and diabetes are two distinct diseases, previous studies have demonstrated that diabetic women have a poor chance of breast cancer survival when compared to nondiabetic women. Well-known key drivers of hyperinsulinemia and insulin resistance, such as insulin and AMPK, are also those involved in breast cancer. This link could possibly contribute to the increased mitogenic effects and risk for aggressive breast cancers in Hispanic women. Based on these findings, metformin, a drug standardly used to treat and prevent hyperglycemia, may be a possible alternative (other than tamoxifen) for breast cancer prevention. Eat, Move, Live (EML), a 5-week community-based program, focuses on targeting possible treatments of chronic diseases and risk reduction through attitude and lifestyle modifications. Exercise, nutritional and health awareness classes were implemented to change participants' perspectives regarding chronic diseases and their susceptibility to other morbidities. Questionnaires were given to the participants at baseline and at two follow-ups (5 weeks and 12 weeks) to assess any changes in their attitudes, behaviors, nutrition, lifestyle and beliefs around taking medication for preventative treatments. A total of 56 participants' pretreatment responses were collected via a five-point Likert scale (1-strongly disagree, 5-strongly agree). Demographic data showed that 69% of the respondents were Hispanic women, of whom 46% completed an education level of high school or less. A majority of the responses averaged a “neutral” response to taking medication for management and prevention of diabetes. We infer that their inability to select a stance in their responses may be associated with the lack of knowledge that the community has regarding chronic diseases and risk-prevention methods. Therefore, we anticipate that availability of proper education tools and resources is essential to potentially prevent future morbidities and mortalities. Ultimately, we aim to establish a pilot study that emphasizes the necessity and importance of interventional programs, like EML, to enhance chemoprevention using metformin and improve health outcomes in high-risk breast cancer populations.

Citation Format: Mayra Serrano, Angelica Sanchez, Christine Thai, Katty Nerio, Cristal Resto, Marisela Garcia, Tanya A. Chavez, Laura L. Kruper, Veronica C. Jones, Lisa D. Yee, Alan Nuñez, Ellen J. Rippberger, Angela K. Wong, Noé R. Chávez, Karen Herold, Chidimma M.K. Kalu, Jackelyn A. Alva-Ornelas, Jerneja Tomsic, Krista M. Round, Regina Agulto, Margarita Robles, Ombeni M. Idassi, Kendall J. Kennedy, Christopher Sistrunk, Victoria L. Seewaldt. Receptiveness of metformin as a breast cancer prevention drug within the Hispanic community [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 B119.

Pleiotropic tumor suppressor functions of WWOX antagonize metastasis

Tumor progression and metastasis are the major causes of death among cancer associated mortality. Metastatic cells acquire features of migration and invasion and usually undergo epithelia-mesenchymal transition (EMT). Acquirement of these various hallmarks rely on different cellular pathways, including TGF-β and Wnt signaling. Recently, we reported that WW domain-containing oxidoreductase (WWOX) acts as a tumor suppressor and has anti-metastatic activities involving regulation of several key microRNAs (miRNAs) in triple-negative breast cancer (TNBC). Here, we report that WWOX restoration in highly metastatic MDA-MB435S cancer cells alters mRNA expression profiles; further, WWOX interacts with various proteins to exert its tumor suppressor function. Careful alignment and analysis of gene and miRNA expression in these cells revealed profound changes in cellular pathways mediating adhesion, invasion and motility. We further demonstrate that WWOX, through regulation of miR-146a levels, regulates SMAD3, which is a member of the TGF-β signaling pathway. Moreover, proteomic analysis of WWOX partners revealed regulation of the Wnt-signaling activation through physical interaction with Disheveled. Altogether, these findings underscore a significant role for WWOX in antagonizing metastasis, further highlighting its role and therapeutic potential in suppressing tumor progression.

A Non-canonical Function of BMAL1 Metabolically Limits Obesity-Promoted Triple-Negative Breast Cancer

The epidemiological association between disrupted circadian rhythms and metabolic diseases is implicated in increased risk of human breast cancer and poor therapeutic outcomes. To define a metabolic phenotype and the underlying molecular mechanism, we applied chronic insulin treatment (CIT) to an in vitro model of triple-negative breast cancer to directly address how BMAL1, a key circadian transcription factor, regulates cancer cell respiration and governs tumor progression. At the cellular level, BMAL1 suppresses the flexibility of mitochondrial substrate usage and the pyruvate-dependent mitochondrial respiration induced by CIT. We established an animal model of diet-induced obesity/hyperinsulinemia and observed that BMAL1 functions as a tumor suppressor in obese, but not lean, mice. Downregulation of BMAL1 is associated with higher risk of metastasis in human breast tumors. In summary, loss of BMAL1 in tumors confers advantages to cancer cells in both intrinsic mitochondrial metabolism and extrinsic inflammatory tumor microenvironment during pre-diabetic obesity/hyperinsulinemia.

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Circadian regulator BMAL1 rewires metabolism in a chronic insulin-treated TNBC model

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Pyruvate links BMAL1 to mitochondrial bioenergetics

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BMAL1 suppresses tumor proliferation and metastasis in hyperinsulinemic obese mice

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BMAL1 influences tumor microenvironment in high-fat-diet-fed mice

Metabolic Health, Insulin, and Breast Cancer: Why Oncologists Should Care About Insulin

Studies investigating the potential link between adult pre-menopausal obesity [as measured by body mass index (BMI)] and triple-negative breast cancer have been inconsistent. Recent studies show that BMI is not an exact measure of metabolic health; individuals can be obese (BMI > 30 kg/m²) and metabolically healthy or lean (BMI < 25 kg/m²) and metabolically unhealthy. Consequently, there is a need to better understand the molecular signaling pathways that might be activated in individuals that are metabolically unhealthy and how these signaling pathways may drive biologically aggressive breast cancer. One key driver of both type-2 diabetes and cancer is insulin. Insulin is a potent hormone that activates many pathways that drive aggressive breast cancer biology. Here, we review (1) the controversial relationship between obesity and breast cancer, (2) the impact of insulin on organs, subcellular components, and cancer processes, (3) the potential link between insulin-signaling and cancer, and (4) consider time points during breast cancer prevention and treatment where insulin-signaling could be better controlled, with the ultimate goal of improving overall health, optimizing breast cancer prevention, and improving breast cancer survival.

Hyperinsulinemia promotes aberrant histone acetylation in triple-negative breast cancer

Background

Hyperinsulinemia, the presence of excess insulin relative to glucose in the blood, is considered to be a poor prognostic indicator for patients with triple-negative breast cancer (TNBC). mTOR, a downstream effector of insulin, enhances mitochondrial biogenesis and activity, thereby increasing acetyl-CoA precursors. Increased acetyl-CoA can, in turn, be utilized by nuclear acetyltransferases for histone acetylation, a critical feature of genome regulation. While signaling pathways downstream of insulin have been established for sometime, the effect of insulin on chromatin remains unclear. We hypothesized that hyperinsulinemia-induced metabolic changes lead to genome-wide changes in histone acetylation in TNBC.

Results

MDA-MB-231 cells were xenografted into hyperinsulinemic and wild-type mice. Tumors in the hyperinsulinemic mice displayed elevated levels of histone acetylation compared to tumors in normal insulin conditions. We show that insulin treatment in vitro leads to global increase in chromatin-associated histone acetylation, in particular at H3K9, through the PI3K/AKT/mTOR pathway. Genome-wide analyses revealed that most promoter regions have an increase in histone acetylation upon insulin treatment. In addition, insulin induces higher levels of reactive oxygen species and DNA damage foci in cells.

Conclusions

These results demonstrate the impact of hyperinsulinemia on altered gene regulation through chromatin and the importance of targeting hyperinsulinemia-induced processes that lead to chromatin dysfunction in TNBC.

Electronic supplementary material

The online version of this article (10.1186/s13072-019-0290-9) contains supplementary material, which is available to authorized users.

Harmonization of Busulfan Plasma Exposure Unit (BPEU): A Community-Initiated Consensus Statement

Busulfan therapeutic drug monitoring (TDM) is often used to achieve target plasma exposures. Variability in busulfan plasma exposure units (BPEU) is a potential source for misinterpretation of publications and protocols and is a barrier to data capture by hematopoietic cell transplantation (HCT) registry databases. We sought to harmonize to a single BPEU for international use. Using Delphi consensus methodology, iterative surveys were sent to an increasing number of relevant clinical stakeholders. In survey 1, 14 stakeholders were asked to identify ideal properties of a BPEU. In survey 2, 52 stakeholders were asked (1) to evaluate BPEU candidates according to ideal BPEU properties established by survey 1 and local position statements for TDM and (2) to identify potential facilitators and barriers to adoption of the harmonized BPEU. The most frequently used BPEU identified, in descending order, were area under the curve (AUC) in μM × min, AUC in mg × h/L, concentration at steady state (Css) in ng/mL, AUC in μM × h, and AUC in μg × h/L. All respondents conceptually agreed on the ideal properties of a BPEU and to adopt a harmonized BPEU. Respondents were equally divided between selecting AUC in μM × min versus mg × h/L for harmonization. AUC in mg × h/L was finally selected as the harmonized BPEU, because it satisfied most of the survey-determined ideal properties for the harmonized BPEU and is read easily understood in the clinical practice environment. Furthermore, 10 major professional societies have endorsed AUC in mg × h/L as the harmonized unit for reporting to HCT registry databases and for use in future protocols and publications.

Obesity and Triple-Negative Breast Cancer: Disparities, Controversies, and Biology

Once considered a problem of Western nations, obesity (body mass index ≥30 kg/m²) has rapidly increased since the 1970s to become a major threat to world health. Since 1970, the face of obesity has changed from a disease of affluence and abundance to a disease of poverty. During the last 10 years, studies have mechanistically linked obesity and an obese tumor microenvironment with signaling pathways that predict aggressive breast cancer biology. For example, in the United States, African American women are more likely than non-Hispanic European American women to be obese and to be diagnosed with triple-negative breast cancer (TNBC). In 2008, the Carolina Breast Study found that obesity (increased waist/hip ratio) was linked to an increased incidence of TNBC in premenopausal and postmenopausal African American women. Subsequently, several groups have investigated the potential link between obesity and TNBC in African American women. To date, the data are complex and sometimes contradictory. We review epidemiologic studies that investigated the potential association among obesity, metabolic syndrome, and TNBC in African American women and mechanistic studies that link insulin signaling to the obese breast microenvironment, tissue inflammation, and aggressive TNBC biology.

Obesity and Triple-Negative Breast Cancer: Disparities, Controversies, and Biology

Once considered a problem of Western nations, obesity (body mass index ≥30 kg/m²) has rapidly increased since the 1970s to become a major threat to world health. Since 1970, the face of obesity has changed from a disease of affluence and abundance to a disease of poverty. During the last 10 years, studies have mechanistically linked obesity and an obese tumor microenvironment with signaling pathways that predict aggressive breast cancer biology. For example, in the United States, African American women are more likely than non-Hispanic European American women to be obese and to be diagnosed with triple-negative breast cancer (TNBC). In 2008, the Carolina Breast Study found that obesity (increased waist/hip ratio) was linked to an increased incidence of TNBC in premenopausal and postmenopausal African American women. Subsequently, several groups have investigated the potential link between obesity and TNBC in African American women. To date, the data are complex and sometimes contradictory. We review epidemiologic studies that investigated the potential association among obesity, metabolic syndrome, and TNBC in African American women and mechanistic studies that link insulin signaling to the obese breast microenvironment, tissue inflammation, and aggressive TNBC biology.

Targeting Aberrant p70S6K Activation for Estrogen Receptor-Negative Breast Cancer Prevention

The prevention of estrogen receptor-negative (ER-) breast cancer remains a major challenge in the cancer prevention field, although antiestrogen and aromatase inhibitors have shown adequate efficacy in preventing estrogen receptor-positive (ER⁺) breast cancer. Lack of commonly expressed, druggable targets is a major obstacle for meeting this challenge. Previously, we detected the activation of Akt signaling pathway in atypical hyperplasic early-stage lesions of patients. In the current study, we found that Akt and the downstream 70 kDa ribosomal protein S6 kinase (p70S6K) signaling pathway was highly activated in ER^- premalignant breast lesions and ER^- breast cancer. In addition, p70S6K activation induced transformation of ER^- human mammary epithelial cells (hMEC). Therefore, we explored the potential of targeting Akt/p70S6K in the p70S6K activated, ER^- hMEC models and mouse mammary tumor models for the prevention of ER^- breast cancer. We found that a clinically applicable Akt/p70S6K dual inhibitor, LY2780301, drastically decreased proliferation of hMECs with ErbB2-induced p70S6K activation via Cyclin B1 inhibition and cell-cycle blockade at G₀-G₁ phase, while it did not significantly reverse the abnormal acinar morphology of these hMECs. In addition, a brief treatment of LY2780301 in MMTV-neu mice that developed atypical hyperplasia (ADH) and mammary intraepithelial neoplasia (MIN) lesions with activated p70S6K was sufficient to suppress S6 phosphorylation and decrease cell proliferation in hyperplasic MECs. In summary, targeting the aberrant Akt/p70S6K activation in ER^- hMEC models in vitro and in the MMTV-neu transgenic mouse model in vivo effectively inhibited Akt/S6K signaling and reduced proliferation of hMECs in vitro and ADH/MIN lesions in vivo, indicating its potential in prevention of p70S6K activated ER^- breast cancer. Cancer Prev Res; 10(11); 641-50. ©2017 AACR.

Multiplexed Detection of MicroRNA Biomarkers Using SERS-Based Inverse Molecular Sentinel (iMS) Nanoprobes

MicroRNAs (miRNAs) have demonstrated great promise as a novel class of biomarkers for early detection of various cancers, including breast cancer. However, due to technical difficulties in detecting these small molecules, miRNAs have not been adopted into routine clinical practice for early diagnostics. Thus, it is important to develop alternative detection strategies that could offer more advantages over conventional methods. Here, we demonstrate the application of a "turn-on" SERS sensing technology, referred to as "inverse Molecular Sentinel (iMS)" nanoprobes, as a homogeneous assay for multiplexed detection of miRNAs. This SERS nanoprobe involves the use of plasmonic-active nanostars as the sensing platform. The "OFF-to-ON" signal switch is based on a nonenzymatic strand-displacement process and the conformational change of stem-loop (hairpin) oligonucleotide probes upon target binding. This technique was previously used to detect a synthetic DNA sequence of interest. In this study, we modified the design of the nanoprobe to be used for the detection of short (22-nt) miRNA sequences. The demonstration of using iMS nanoprobes to detect miRNAs in real biological samples was performed with total small RNA extracted from breast cancer cell lines. The multiplex capability of the iMS technique was demonstrated using a mixture of the two differently labeled nanoprobes to detect miR-21 and miR-34a miRNA biomarkers for breast cancer. The results of this study demonstrate the feasibility of applying the iMS technique for multiplexed detection of short miRNAs molecules.

Förster resonance energy transfer to impart signal-on and -off capabilities in a single microRNA biosensor

The influence of spacer molecules and different dye pairs on the signal-on/off analytical metrics of a Förster Resonance Energy Transfer based microRNA biosensor.

Abstract PR11: Loss of imprinting: Tying prenatal diet to the aggressive biology of triple-negative breast cancer

Background: Genomic imprinting is an inherited form of parent-of-origin specific epigenetic gene regulation that is dysregulated by poor prenatal nutrition and environmental toxins. Loss of normal imprinting results in a functional diploid state and overexpression of the imprinted gene. KCNK9 encodes for TASK3, a pH-regulated potassium channel membrane protein that is overexpressed in 40% of breast cancers; however, KCNK9 gene amplification accounts for increased expression in &lt;10% of these breast cancers.

Methods and Results: Using patient samples we showed that KCNK9 has imprinted expression in breast tissue, and identified the differentially methylated region (DMR) controlling its imprint status. We showed that loss of methylation (LOM) at the DMR, coupled with biallelic expression of KCNK9, occurred in 75% of triple-negative breast cancers (TNBC), and that association between LOM and TNBC status was highly significant in African-Americans, but not in Caucasians. Functional studies show that loss of KCNK9 imprinting leads to an increase in mitochondrial membrane potential and apoptosis resistance. Further, expression of a dominant-negative TASK3 in TASK3-overexpressing TNBC cells resulted in decreased mitochondrial membrane potential, decreased glucose uptake and apoptosis-sensitivity; conversely, overexpression of TASK3 in mammary epithelial cells with baseline TASK3 protein expression, increased mitochondrial membrane potential, increased glucose uptake and promoted apoptosis-resistance.

Significance: This is the first identification of the KCNK9 DMR, and demonstration that its LOM is associated with increases in mitochondrial membrane potential, glucose uptake and apoptosis resistance. Thus, patients with TNBC and KCNK9 overexpression may benefit from known low toxicity TASK3 inhibitors for the prevention and treatment of breast cancer.

This abstract was also presented as Poster A79.

Citation Format: Shraddha R. Desai, Eric C. Dietze, David Skaar, Randy L. Jirtle, Victoria L. Seewaldt. Loss of imprinting: Tying prenatal diet to the aggressive biology of triple-negative breast cancer. [abstract]. In: Proceedings of the Seventh AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 9-12, 2014; San Antonio, TX. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2015;24(10 Suppl):Abstract nr PR11.

Src Inhibition Blocks c-Myc Translation and Glucose Metabolism to Prevent the Development of Breast Cancer

Preventing breast cancer will require the development of targeted strategies that can effectively block disease progression. Tamoxifen and aromatase inhibitors are effective in addressing estrogen receptor-positive (ER(+)) breast cancer development, but estrogen receptor-negative (ER(-)) breast cancer remains an unmet challenge due to gaps in pathobiologic understanding. In this study, we used reverse-phase protein array to identify activation of Src kinase as an early signaling alteration in premalignant breast lesions of women who did not respond to tamoxifen, a widely used ER antagonist for hormonal therapy of breast cancer. Src kinase blockade with the small-molecule inhibitor saracatinib prevented the disorganized three-dimensional growth of ER(-) mammary epithelial cells in vitro and delayed the development of premalignant lesions and tumors in vivo in mouse models developing HER2(+) and ER(-) mammary tumors, extending tumor-free and overall survival. Mechanistic investigations revealed that Src blockade reduced glucose metabolism as a result of an inhibition in ERK1/2-MNK1-eIF4E-mediated cap-dependent translation of c-Myc and transcription of the glucose transporter GLUT1, thereby limiting energy available for cell growth. Taken together, our results provide a sound rationale to target Src pathways in premalignant breast lesions to limit the development of breast cancers.

WWOX loss activates aerobic glycolysis

Cancer cells undergo reprogramming of glucose metabolism to limit energy production to glycolysis-a state known as "aerobic glycolysis." Hypoxia-inducible factor 1 (HIF1α) is a transcription factor that regulates many genes responsible for this switch. As discussed here, new data suggest that the tumor suppressor WW domain-containing oxidoreductase (WWOX) modulates HIF1α, thereby regulating this metabolic state.

Triple-negative breast cancer in African-American women: disparities versus biology

Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype that disproportionately affects BRCA1 mutation carriers and young women of African origin. There is evidence that African-American women with TNBC have worse clinical outcomes than women of European descent. However, it is unclear whether survival differences persist after adjusting for disparities in access to health-care treatment, co-morbid disease and income. It remains controversial whether TNBC in African-American women is a molecularly distinct disease or whether African-American women have a higher incidence of aggressive biology driven by disparities: there is evidence in support of both. Understanding the relative contributions of biology and disparities is essential for improving the poor survival rate of African-American women with TNBC.

Tumor mechanics and metabolic dysfunction

Desmosplasia is a characteristic of most solid tumors and leads to fibrosis through abnormal extracellular matrix (ECM) deposition, remodeling, and posttranslational modifications. The resulting stiff tumor stroma not only compromises vascular integrity to induce hypoxia and impede drug delivery, but also promotes aggressiveness by potentiating the activity of key growth, invasion, and survival pathways. Intriguingly, many of the protumorigenic signaling pathways that are mechanically activated by ECM stiffness also promote glucose uptake and aerobic glycolysis, and an altered metabolism is a recognized hallmark of cancer. Indeed, emerging evidence suggests that metabolic alterations and an abnormal ECM may cooperatively drive cancer cell aggression and treatment resistance. Accordingly, improved methods to monitor tissue mechanics and metabolism promise to improve diagnostics and treatments to ameliorate ECM stiffening and elevated mechanosignaling may improve patient outcome. Here we discuss the interplay between ECM mechanics and metabolism in tumor biology and suggest that monitoring these processes and targeting their regulatory pathways may improve diagnostics, therapy, and the prevention of malignant transformation.

Model of tumor dormancy/recurrence after short-term chemotherapy

Although many tumors regress in response to neoadjuvant chemotherapy, residual tumor cells are detected in most cancer patients post-treatment. These residual tumor cells are thought to remain dormant for years before resuming growth, resulting in tumor recurrence. Considering that recurrent tumors are most often responsible for patient mortality, there exists an urgent need to study signaling pathways that drive tumor dormancy/recurrence. We have developed an in vitro model of tumor dormancy/recurrence. Short-term exposure of tumor cells (breast or prostate) to chemotherapy at clinically relevant doses enriches for a dormant tumor cell population. Several days after removing chemotherapy, dormant tumor cells regain proliferative ability and establish colonies, resembling tumor recurrence. Tumor cells from “recurrent” colonies exhibit increased chemotherapy resistance, similar to the therapy resistance of recurrent tumors in cancer patients. Previous studies using long-term chemotherapy selection models identified acquired mutations that drive tumor resistance. In contrast, our short term chemotherapy exposure model enriches for a slow-cycling, dormant, chemo-resistant tumor cell sub-population that can resume growth after drug removal. Studying unique signaling pathways in dormant tumor cells enriched by short-term chemotherapy treatment is expected to identify novel therapeutic targets for preventing tumor recurrence.

Abstract 4880: PELP1 localization as a biomarker for early mammary carcinogenesis and response to tamoxifen chemoprevention

Progress in breast cancer prevention is currently limited by our lack of biological markers to identify which high-risk women will progress to develop breast cancer and which women will respond to chemoprevention therapies, such as tamoxifen (Tam). While Tam has proven to be effective for breast cancer chemoprevention, Tam therapy only reduces the risk of developing breast cancer by approximately 50%. Therefore, identification of biomarkers is essential to determine which women will benefit from Tam chemoprevention.

We have been studying the role of PELP1 in early mammary carcinogenesis and response to Tam chemoprevention. PELP1 subcellular localization is primarily nuclear in normal mammary epithelium, but it has been shown to be localized to the cytoplasm of &lt;50% of PELP1 positive breast tumors. Targeting PELP1 to the cytoplasm leads to activation of non-genomic signaling to ERK1/2 and AKT and promotes Tam-resistance breast cancer cells. Additionally, it has been shown that transgenic mice expressing cytoplasmic PELP1 develop mammary gland hyperplasia. We have developed human mammary epithelial cell (HMEC) lines that express either vector control, wild-type PELP1 or a mutant of PELP1 in which the nuclear localization sequence has been mutated and the protein is predominately cytoplasmic (PELP1-cyto). Data generated using these cells lines indicates that PELP1-cyto, but not wild-type PELP1, promotes Tam-resistance. Our data also suggest that Tam treatment results in non-apoptotic death of HMECs. We found that Tam treatment induces the expression of LC3, an autophagy marker, and that Tam-induced LC3 expression is blocked in HMECs expressing PELP1-cyto. Together these data suggest that Tam-induced autophagy may be the mechanism of death in the HMEC cell lines and that cytoplasmic PELP1 may inhibit autophagic death.

The objective of our current research is to determine if cytoplasmic PELP1 expression promotes expression of a novel gene signature that predicts response to Tam chemoprevention. We are currently testing models of early mammary carcinogenesis (pre-stasis, post-stasis, and immortal) for their response to Tam in the presence and absence of cytoplasmic PELP1. Microarray analysis will be performed on RNA from cell line that represents the earliest point in mammary carcinogenesis in which we see an effect of PELP1 expression. We expect that these studies will provide us with gene signatures that can predict cytoplasmic PELP1 expression and Tam resistance in early mammary carcinogenesis. Gene signatures will then be validated using existing gene array databases. These studies have the potential to lead to additional targets for chemoprevention and benefit women who are resistant to Tam chemoprevention.

Citation Format: Julie Hanson Ostrander, Brian Girard, Tarah M. Regan-Anderson, Siya Lem, Victoria L. Seewaldt. PELP1 localization as a biomarker for early mammary carcinogenesis and response to tamoxifen chemoprevention. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4880. doi:10.1158/1538-7445.AM2013-4880

Abstract LB-191: Cytological atypia predicts short-term breast cancer risk in women from high-risk families that lack a BRCA mutation

Background: Women with deleterious mutations in BRCA1/2 have a 9- to 36-fold increased risk of breast cancer compared with general population rates. However, there are a significant number of women whose families have multi-generation premenopausal breast cancers and lack an identified BRCA-mutation. Currently we lack strategies to predict the development of breast cancer in women from BRCA-negative families. Random Periareolar Fine Needle Aspiration (RPFNA) is a research technique developed to test for “field effects” in high-risk women. Carol Fabian previously demonstrated that atypia in RPFNA predicted breast cancer risk, however, many women in this cohort were known BRCA mutation carriers.

We investigated whether cytological atypia in RPFNA predicts the subsequent development of breast cancer in women from BRCA-negative breast cancer families.

Results: From 01/01/03 to 07/01/12, we performed RPFNA in 254 high-risk BRCA-negative women. Women underwent yearly mammogram/Magnetic Resonance Imaging (MRI) and bi-annual clinical breast exam. During 6.5 women-years of follow-up, 24 new breast cancers were diagnosed. The median age of the 254 women in this study was 48, and the median BMI was 24. Eighty-six percent (218) of the women were Caucasian, 13% (32) were African-American, and 2 women were Native Americans. Sixty-eight women presented with cytologic-atypia in at least one breast; 16 of these women had cytologic-atypia in both breasts. Fourteen (21%) of the 68 women with baseline cytologic-atypia later developed cancer in a breast that had had baseline cytologic-atypia; none of the 68 women developed cancer in a breast without baseline cytologic-atypia. One hundred eighty-six women did not have cytologic-atypia at baseline; 10 (5%) of these women developed cancer. Ten women had a prophylactic mastectomy and were censored at the date of mastectomy. The median length of follow-up among the uncensored patients was 74 months. In the baseline atypic and non-atypic groups, the 48-month cumulative incidence of cancer development was 0.22 (95% confidence interval [CI], 0.13-0.34) and 0.04 (95% CI, 0.02-0.08), respectively. Atypia was significantly associated with cancer development both with and without controlling for covariates (p &lt; 0.001). The covariate-adjusted hazard ratio (CV-AHR) for cytologic-atypia was 6.3 (95% CI, 1.7-24.2). The hazard ratios for the covariates were as follows: age (1.01; 95% CI, 0.89-1.16), BMI (1.02; 95% CI, 0.91-1.15), menopausal status (0.16; 95% CI, 0.01-2.60), Gail Risk (1.18; 95% CI, 1.03-1.35) and mammographic density for scattered (1.7; 95% CI, 0.27-10.9) and heterogenetic (1.10; 95% CI, 0.20-6.01) compared to the reference type of extreme.

Conclusions: This is the first demonstration that in women from high-risk BRCA mutation-negative families, cytologic-atypia in RPFNA is associated with the subsequent development of breast cancer.

Citation Format: Victoria L. Seewaldt, Bercedis Peterson, Gloria Broadwater. Cytological atypia predicts short-term breast cancer risk in women from high-risk families that lack a BRCA mutation. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-191. doi:10.1158/1538-7445.AM2013-LB-191