Human Breast Cancer Tissue Microarrays Research Articles

Analysis of the PARP1, ADP-Ribosylation, and TRIP12 Triad With Markers of Patient Outcome in Human Breast Cancer

PARP inhibitors (PARPi) are increasingly used in breast cancer therapy, including high-grade triple-negative breast cancer (TNBC) treatment. Varying treatment responses and PARPi resistance with relapse currently pose limitations to the efficacy of PARPi therapy. The pathobiological reasons why individual patients respond differently to PARPi are poorly understood. In this study, we analyzed expression of PARP1, the main target of PARPi, in normal breast tissue, breast cancer, and its precursor lesions using human breast cancer tissue microarrays covering a total of 824 patients, including more than 100 TNBC cases. In parallel, we analyzed nuclear adenosine diphosphate (ADP)-ribosylation as a marker of PARP1 activity and TRIP12, an antagonist of PARPi-induced PARP1 trapping. Although we found PARP1 expression to be generally increased in invasive breast cancer, PARP1 protein levels and nuclear ADP-ribosylation were lower in higher tumor grade and TNBC samples than non-TNBCs. Cancers with low levels of PARP1 and low levels of nuclear ADP-ribosylation were associated with significantly reduced overall survival. This effect was even more pronounced in cases with high levels of TRIP12. These results indicate that PARP1-dependent DNA repair capacity may be compromised in aggressive breast cancers, potentially fueling enhanced accumulation of mutations. Moreover, the results revealed a subset of breast cancers with low PARP1, low nuclear ADP-ribosylation, and high TRIP12 levels, which may compromise their response to PARPi, suggesting a combination of markers for PARP1 abundance, enzymatic activity, and trapping capabilities might aid patient stratification for PARPi therapy.

Evaluating near-infrared photoimmunotherapy for targeting fibroblast activation protein-α expressing cells in vitro and in vivo.

Photoimmunotherapy (PIT), carried out using an Ab conjugated to the near infrared dye IRDye700DX, is achieving significant success in target-specific elimination of cells. Fibroblast activation protein alpha (FAP-α) is an important target in cancer because of its expression by cancer-associated fibroblasts (CAFs) as well as by some cancer cells. Cancer-associated fibroblasts that express FAP-α have protumorigenic and immune suppressive functions. Using immunohistochemistry of human breast cancer tissue microarrays, we identified an increase of FAP-α+ CAFs in invasive breast cancer tissue compared to adjacent normal tissue. We found FAP-α expression increased in fibroblasts cocultured with cancer cells. In proof-of-principle studies, we engineered human FAP-α overexpressing MDA-MB-231 and HT-1080 cancer cells and murine FAP-α overexpressing NIH-3T3 fibroblasts to evaluate several anti-FAP-α Abs and selected AF3715 based on its high binding affinity with both human and mouse FAP-α. After conjugation of AF3715 with the phthalocyanine dye IR700, the resultant Ab conjugate, FAP-α-IR700, was evaluated in cells and tumors for its specificity and effectiveness in eliminating FAP-α expressing cell populations with PIT. Fibroblast activation protein-α-IR700-PIT resulted in effective FAP-α-specific cell killing in the engineered cancer cells and in two patient-derived CAFs in a dose-dependent manner. Following an intravenous injection, FAP-α-IR700 retention was three-fold higher than IgG-IR700 in FAP-α overexpressing tumors, and two-fold higher compared to WT tumors. Fibroblast activation protein-α-IR700-PIT resulted in significant growth inhibition of tumors derived from FAP-α overexpressing human cancer cells. A reduction of endogenous FAP-α+ murine CAFs was identified at 7 days after FAP-α-IR700-PIT. Fibroblast activation protein-α-targeted near infrared PIT presents a promising strategy to eliminate FAP-α+ CAFs.

Quality Assessment of Proteins and RNA Following Storage in Archival Formalin-Fixed Paraffin-Embedded Human Breast Cancer Tissue Microarray Sections.

Although the immunogenicity of formalin-fixed paraffin-embedded tissue sections can decrease during storage and transport, the exact mechanism of antigenic loss and how to prevent it are not clear. Herein, we investigated changes in the expression of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER-2), E-cadherin, and Ki-67 in human breast tissue microarray (TMA) tissue sections stored for up to 3 months in dry and wet conditions. The positive rates of ER and PR expression were minimally changed after 3 months of storage, but the Allred scores of ER and PR stored in humid conditions decreased remarkably in comparison to fresh-cut tissue. The HER-2 antigenicity and RNA integrity of breast TMA sections stored in dry conditions diminished gradually with storage time, whereas the immunoreactivity and RNA quality of HER-2 in humid conditions decreased sharply as storage length increased. The area and intensity of E-cadherin staining in tissue sections stored in dry conditions did not change significantly and were minimally changed after 3 months, respectively. In contrast, the area and intensity of E-cadherin staining in tissue sections stored in humid conditions decreased significantly as storage length increased. Finally, the Ki-67 labeling index of tissue sections stored for 3 months in dry (9% decrease) and wet (31.9% decrease) conditions was decreased in comparison to fresh sections. In conclusion, these results indicate that water is a crucial factor for protein and RNA degradation in stored tissue sections, and detailed guidelines are required in the clinic.

High levels of unfolded protein response component CHAC1 associates with cancer progression signatures in malignant breast cancer tissues.

The aberrant mRNA expression of a UPR component Cation transport regulator homolog 1 (CHAC1) has been reported to be associated with poor survival in breast and ovarian cancer patients, however, the expression of CHAC1 at protein levels in malignant breast tissues is underreported. The following study aimed at analyzing CHAC1 protein expression in malignant breast cancer tissues. Evaluation of CHAC1 expression in invasive ductal carcinomas (IDCs) with known ER, PR, and HER2 status was carried out using immunohistochemistry (IHC) with CHAC1 specific antibody. The Human breast cancer tissue microarray (TMA, cat# BR1503f, US Biomax, Inc., Rockville, MD) was used to determine CHAC1 expression. The analysis of CHAC1 IHC was done to determine its expression in terms of molecular subtypes of breast cancer, lymph node status, and proliferation index using Qu-Path software. Survival analysis was studied with a Kaplan-Meier plotter. Immunohistochemical analysis of CHAC1 in breast cancer tissues showed significant up-regulation of CHAC1 as compared to the adjacent normal and benign tissues. Interestingly, CHAC1 immunostaining revealed high expression in tumor tissues with high proliferation and positive lymph node metastasis suggesting that CHAC1 might have an important role to play in breast cancer progression. Furthermore, high CHAC1 expression is associated with poor overall survival (OS) in large breast cancer patient cohorts. As a higher expression of CHAC1 was observed in tissue cores with high Ki67 index and positive lymph node metastasis it may be concluded that enhanced CHAC1 expression correlates with proliferation and metastasis. The further analysis of breast cancer patients' survival data through KM plot indicated that high CHAC1 expression is associated with a bad prognosis hinting that CHAC1 may have a possible prognostic significance in breast cancer.

Toward reproducible, scalable, and robust data analysis across multiplex tissue imaging platforms

SummaryThe emergence of megascale single-cell multiplex tissue imaging (MTI) datasets necessitates reproducible, scalable, and robust tools for cell phenotyping and spatial analysis. We developed open-source, graphics processing unit (GPU)-accelerated tools for intensity normalization, phenotyping, and microenvironment characterization. We deploy the toolkit on a human breast cancer (BC) tissue microarray stained by cyclic immunofluorescence and present the first cross-validation of breast cancer cell phenotypes derived by using two different MTI platforms. Finally, we demonstrate an integrative phenotypic and spatial analysis revealing BC subtype-specific features.

E3 ligase-inactivation rewires CBL interactome to elicit oncogenesis by hijacking RTK\u2013CBL\u2013CIN85 axis

Casitas B-lineage lymphoma (CBL) is a ubiquitin ligase (E3) that becomes activated upon Tyr371-phosphorylation and targets receptor protein tyrosine kinases for ubiquitin-mediated degradation. Deregulation of CBL and its E3 activity is observed in myeloproliferative neoplasms and other cancers, including breast, colon, and prostate cancer. Here, we explore the oncogenic mechanism of E3-inactive CBL mutants identified in myeloproliferative neoplasms. We show that these mutants bind strongly to CIN85 under normal growth conditions and alter the CBL interactome. Lack of E3 activity deregulates CIN85 endosomal trafficking, leading to an altered transcriptome that amplifies signaling events to promote oncogenesis. Disruption of CBL mutant interactions with EGFR or CIN85 reduces oncogenic transformation. Given the importance of the CBL–CIN85 interaction in breast cancers, we examined the expression levels of CIN85, CBL, and the status of Tyr371-phosphorylated CBL (pCBL) in human breast cancer tissue microarrays. Interestingly, pCBL shows an inverse correlation with both CIN85 and CBL, suggesting that high expression of inactivated CBL could coordinate with CIN85 for breast cancer progression. Inhibition of the CBL–CIN85 interaction with a proline-rich peptide of CBL that binds CIN85 reduced the proliferation of MDA-MB-231 cells. Together, these results provide a rationale for exploring the potential of targeting the EGFR–CBL–CIN85 axis in CBL-inactivated mutant cancers.

Regulatory T lymphocyte infiltration in metastatic breast cancer\u2014an independent prognostic factor that changes with tumor progression

BackgroundPatients diagnosed with metastatic breast cancer have poor outcome with a median survival of approximately 2 years. While novel therapeutic options are urgently needed, the great majority of breast cancer research has focused on the primary tumor and less is known about metastatic breast cancer and the prognostic impact of the metastatic tumor microenvironment. Here we investigate the immune landscape in unique clinical material. We explore how the immune landscape changes with metastatic progression and elucidate the prognostic role of immune cells infiltrating primary tumors and corresponding lymph node and more importantly distant metastases.MethodsImmunohistochemical staining was performed on human breast cancer tissue microarrays from primary tumors (n = 231), lymph node metastases (n = 129), and distant metastases (n = 43). Infiltration levels of T lymphocytes (CD3+), regulatory T lymphocytes (Tregs, FOXP3+), macrophages (CD68+), and neutrophils (NE+) were assessed in primary tumors. T lymphocytes and Tregs were further investigated in lymph node and distant metastases.ResultsT lymphocyte and Treg infiltration were the most clinically important immune cell populations in primary tumors. Infiltration of T lymphocytes and Tregs in primary tumors correlated with proliferation (P = 0.007, P = 0.000) and estrogen receptor negativity (P = 0.046, P = 0.026). While both T lymphocyte and Treg infiltration had a negative correlation to luminal A subtype (P = 0.031, P = 0.000), only Treg infiltration correlated to luminal B (P = 0.034) and triple-negative subtype (P = 0.019). In primary tumors, infiltration of T lymphocytes was an independent prognostic factor for recurrence-free survival (HR = 1.77, CI = 1.01–3.13, P = 0.048), while Treg infiltration was an independent prognostic factor for breast cancer-specific survival (HR = 1.72, CI = 1.14–2.59, P = 0.01). Moreover, breast cancer patients with Treg infiltration in their distant metastases had poor post-recurrence survival (P = 0.039). Treg infiltration levels changed with metastatic tumor progression in 50% of the patients, but there was no significant trend toward neither lower nor higher infiltration.ConclusionTreg infiltration could have clinical applicability as a prognostic biomarker, deciphering metastatic breast cancer patients with worse prognosis, and accordingly, could be a suitable immunotherapeutic target for patients with metastatic breast cancer. Importantly, half of the patients had changes in Treg infiltration during the course of metastatic progression emphasizing the need to characterize the metastatic immune landscape.

Abstract 4563: Immunoprevention of triple negative breast cancer by a multi-antigen, multi-peptide vaccine

Abstract Triple negative breast cancer (TNBC) is the most aggressive sub-type of breast cancer, comprising approximately 20% of all breast cancers, and has a poor prognosis due to its aggressive behavior and lack of effective targeted therapies. In the present study, we employed transcriptome and protein analyses to select genes that are uniquely overexpressed in human triple-negative breast cancer. Overexpression of selected genes, Cyclin A2, CDK1, Cyclin E2, PRC1, Kif15, TPX2, Ki67, Top2A, were confirmed on human breast cancer tissue microarrays and in TNBC derived cell lines from C3(1)/TAg mice. Antigen-specific MHC class II epitopes with promiscuous high-binding affinity were identified using the “combined scoring system”, based on their potential to elicit a selective Th1 immunity. Furthermore, all peptides were selected to have over 85% amino acid sequence homology between human and mice for potential clinical translation. Strong immunogenic peptides from five antigens were selected by immunogenicity testing in tumor naïve mice based on high IFN-γ and low IL-10 ELISpot response data. The selected peptides, Cyclin A2 (#335), CDK1 (#113), Cyclin E2 (#93, 298, 334), KIF15 (#129), and Top2A (#236, 410, 606), were combined to form a multi-antigen, multi-peptide vaccine (MAMPV). The tumor preventive efficacy of the MAMPV was evaluated in syngraft study using a TNBC model: C3(1)/TAg-REAR mice and a TNBC cell line derived from C3(1)/TAg (M6). MAMPV-vaccinated animals demonstrated a significant reduction in tumor volume, and significantly higher tumor infiltration of CD4+ T cells compared to the control animals. Pathological examination of major organs did not reveal any toxicity associated with the vaccine. Similar tumor preventive efficacy was demonstrated in genetically engineered mouse model (GEMM) using C3(1)/TAg mice. Taken together, our data indicate that formulation of the multi-antigen multi-peptide vaccine is highly immunogenic and has the potential to be safe and efficacious in the immunoprevention of TNBC. Citation Format: Yian Wang. Immunoprevention of triple negative breast cancer by a multi-antigen, multi-peptide vaccine [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4563.

Novel mechanistic targets of forkhead box Q1 transcription factor in human breast cancer cells.

The transcription factor forkhead box Q1 (FoxQ1) is overexpressed in different solid tumors including breast cancer, but the mechanism underlying its oncogenic function is still not fully understood. In this study, we compared RNA-seq data from FoxQ1 overexpressing SUM159 cells with that of empty vector-transfected control cells to identify novel mechanistic targets of this transcription factor. Analysis of The Cancer Genome Atlas (TCGA) data set revealed significantly higher expression of FoxQ1 in black breast cancer patients compared with white women with this disease. In contrast, expression of FoxQ1 was comparable in ductal and lobular carcinomas in the breast cancer TCGA data set. Complementing our published findings in basal-like subtype, immunohistochemistry revealed upregulation of FoxQ1 protein in luminal-type human breast cancer tissue microarrays when compared with normal mammary tissues. Many previously reported transcriptional targets of FoxQ1 (eg, E-cadherin, N-cadherin, fibronectin 1, etc) were verified from the RNA-seq analysis. FoxQ1 overexpression resulted in the downregulation of genes associated with cell cycle checkpoints, M phase, and cellular response to stress/external stimuli as evidenced from the Reactome pathway analysis. Consequently, FoxQ1 overexpression resulted in mitotic arrest in basal-like SUM159 and human mammary epithelial cell line, but not in luminal-type MCF-7 cells. Finally, we show for the first time that FoxQ1 is a direct transcriptional regulator of interleukin (IL)-1α, IL-8, and vascular endothelial growth factor in breast cancer cells as evidenced by chromatin immunoprecipitation assay. In conclusion, the present study reports novel mechanistic targets of FoxQ1 in human breast cancer cells.

Increased SIX-1 expression promotes breast cancer metastasis by regulating lncATB-miR-200s-ZEB1 axis.

Patients with advanced breast cancer (BC) showed a higher incidence of regional and distant metastases. Sine oculis homeobox homolog 1 (SIX‐1) has been confirmed to be a key tumorigenic and metastatic regulator in BC progression. Yet, molecular mechanisms behind SIX‐1‐induced BC metastases remain largely unknown. Here we found that SIX‐1 was frequently up‐regulated in BC and correlated with poor outcomes when tested in human BC tissue microarray. Then, we manipulated the expression of SIX‐1 by via shRNA‐mediated knockdown and lentivirus‐mediated overexpression. Transwell assay in vitro and lung metastases model of nude mice in vivo showed that SIX‐1 promoted BC cell invasion and migration in vitro, and facilitated metastases in vivo. Mechanistically, SIX‐1 could promote the transcription of lncATB, which exerts critical pro‐metastatic role in BC by directly binding to the miR‐200 family, especially for miR‐200c, to induce EMT and promote metastases. In conclusion, SIX‐1 exerts its pro‐metastatic role in BC through lncATB/miR‐200s axis of EMT signalling pathway and could act as an important diagnostic marker as well as a significant therapeutic target for clinically advanced BC.

Abstract P5-04-14: Recombinant Slit2 suppresses breast cancer metastasis by activating anti-tumor macrophages

Abstract Metastasis is a major cause of mortality in breast cancer patients in part due to the lack of clinically established targeted therapies. Approximately 5%-20% of patients with Stage II, and ~50% of patients with stage III will recur distally and are likely to die from their disease. Metastatic, or stage IV breast cancers, have a 5-year relative survival rate of about 22%. The expression of a tumor suppressor protein, Slit2 has been shown to be downregulated in various types of tumors including breast cancer. The Slit2 acts through Roundabout Homolog1 (Robo1) receptor. Previously it has been shown that ectopic expression of Slit2 inhibits human MCF-7 breast cancer cell line xenograft tumor growth in mice. However, its role in breast cancer metastasis, tumor microenvironment (TME) and anti-tumor immunity has not been studied before. By using genetically engineered human breast cancer cells, spontaneous mammary tumor and pre-clinical mouse models, we evaluated the role of Slit2 in inhibiting breast cancer growth, metastasis by activating anti-tumor immune response. To study the role of Slit2 in breast cancer, we implanted Slit2 overexpressing human breast cancer cell line MDA-MB-231 (231-Slit2) or vector control cells (231-Vec) to the mammary fat-pads of NOD/SCID/gamma (NSG) mice and observed that 231-Slit2 had significantly reduced tumor growth and metastasis to the lungs compared to 231-Vec. To further confirm the anti-metastatic role of Slit2, we treated mouse mammary tumor virus- Polyoma Middle T antigen (MMTV-PyMT) mammary tumor model and MVT-1 orthotopic tumor bearing FVB/J wildtype mice with recombinant Slit2 (rSlit2) that resulted in significantly reduced tumor growth and metastasis to the lungs in both the models compared to PBS treated mice. The ex-vivo immunofluorescence and flow cytometry studies revealed that Slit2 treated tumors possess a very high number of tumor phagocytic macrophages compared to PBS. In-vitro analysis also showed that rSlit2 treated mouse macrophages (RAW264.7) has higher bacterial particle phagocytic ability. Further analysis of tumors elucidated that Slit2 treated tumors recruited higher number of CD4+ and CD8+ T-cells. In addition, The CD8+ cells were also positive for Granzyme-b showing higher number of effector T-cells in the Slit2 tumors compared to PBS. By using human breast cancer tissue microarray (TMA), we have found that Slit2 expression significantly correlates with better overall survival. These observations highlight the ability of Slit2 to enhance tumor phagocytic macrophages and anti-tumor CD8+/Granzyme-b+ T-cells, thereby restricting tumor growth and lung metastasis. These studies suggest that Slit2 could be used as a novel immunomodulatory therapeutic agent metastatic breast cancer. Citation Format: Dinesh Kumar Ahirwar, Ramesh Kumar Ganju, Sanjay Mishra, Konstantin Shilo, Kirti Kaul. Recombinant Slit2 suppresses breast cancer metastasis by activating anti-tumor macrophages [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 P5-04-14.

Abstract 647: Immunoprevention of triple negative breast cancer by a TOP2A multi-peptide vaccine

Abstract Triple negative breast cancer (TNBC) comprises approximately 20% of all breast cancers, and it has a poor prognosis due to aggressive growth characteristics and lack of effective targeted therapies. Emerging data suggest vaccination as a promising approach to prevent TNBC as well as other cancer types, but appropriate vaccine targets need to be identified. In the present study, we employed in silico analyses to select genes that are uniquely expressed in TNBC. Topoisomerase 2 alpha (Top2A) was found to be highly expressed in human TNBC. Top2A is a key enzyme in DNA replication and has been identified as a target of anti-cancer therapy. Overexpression of Top2A was confirmed in human breast cancer tissue microarrays and in mouse TNBCs derived from C3(1)/TAg mice. Top2A-specific MHC class II epitopes with optimal binding affinity were identified using the “combined scoring system”, based on their potential to elicit a Th1 immune response. Furthermore, all peptides were selected to have 100% amino acid sequence homology between humans and mice for potential clinical translation. Four Top2A peptides with strong immunogenic responses were selected by immunization of tumor naïve mice followed by IFN-γ-based ELISPOT assays. These peptides were combined to form a multi-peptide Top2A vaccine. The anti-tumor efficacy of the Top2A vaccine was tested in a preventive setting using a syngeneic TNBC model in C3(1)/TAg-REAR mice. Vaccinated animals demonstrated a significant reduction in tumor growth when compared to the adjuvant control with tumor size decreasing from 278.1 mm3 in adjuvant control to 150.4 mm3 in vaccinated group (p < 0.05). Taken together, our data clearly demonstrate that the Top2A multi-peptide vaccine is highly immunogenic and provides immunopreventive efficacy against TNBC in mice. Citation Format: Sang Beom Lee, Jing Pan, Yueqiang Jiang, Katie Palen, Bryon Johnson, Romaine Ingrid Fernando, Shizuko Sei, Ronald Lubet, Ming You, Yian Wang. Immunoprevention of triple negative breast cancer by a TOP2A multi-peptide vaccine [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 647.

Abstract 4561: Slit2 inhibits breast cancer growth and metastasis by activating anti-tumor immune response

Abstract Metastasis is a major cause of mortality in breast cancer patients in part due to the lack of clinically established targeted therapies. Approximately 5%-20% of patients with Stage II, and ~50% of patients with stage III will recur distally and are likely to die from their disease. Metastatic, or stage IV breast cancers, have a 5-year relative survival rate of about 22%. The expression of a tumor suppressor protein, Slit2 has been shown to be downregulated in various types of tumors including breast cancer. The Slit2 acts through Roundabout Homolog1 (Robo1) receptor. Previously it has been shown that ectopic expression of Slit2 inhibits human MCF-7 breast cancer cell line xenograft tumor growth in mice. However, its role in breast cancer metastasis, tumor microenvironment (TME) and anti-tumor immunity has not been studied before. By using genetically engineered human breast cancer cells, spontaneous mammary tumor and pre-clinical mouse models, we evaluated the role of Slit2 in inhibiting breast cancer growth, metastasis by activating anti-tumor immune response. To study the role of Slit2 in breast cancer, we implanted Slit2 overexpressing human breast cancer cell line MDA-MB-231 (231-Sli2) or vector control cells (231-Vec) to the mammary fat-pads of NOD/SCID/gamma (NSG) mice and observed that 231-Slit2 had significantly reduced tumor growth and metastasis to the lungs compared to 231-Vec. To further confirm the anti-metastatic role of Slit2, we treated mouse mammary tumor virus- Polyoma Middle T antigen (MMTV-PyMT) mammary tumor model and MVT-1 orthotopic tumor bearing FVB/J wildtype mice with recombinant Slit2 (rSlit2) that resulted in significantly reduced tumor growth and metastasis to the lungs in both the models compared to PBS treated mice. The ex-vivo immunofluorescence and flow cytometry studies revealed that Slit2 treated tumors possess a very high number of tumor phagocytic macrophages compared to PBS. In-vitro analysis also showed that rSlit2 treated mouse macrophages (RAW264.7) has higher bacterial particle phagocytic ability. Further analysis of tumors elucidated that Slit2 treated tumors recruited higher number of CD4+ and CD8+ T-cells. In addition, The CD8+ cells were also positive for Granzyme-b showing higher number of effector T-cells in the Slit2 tumors compared to PBS. By using human breast cancer tissue microarray (TMA), we have found that Slit2 expression significantly correlates with better overall survival. These observations highlight the ability of Slit2 to enhance tumor phagocytic macrophages and anti-tumor CD8+/Granzyme-b+ T-cells, thereby restricting tumor growth and lung metastasis. These studies suggest that Slit2 could be used as a novel immunomodulatory therapeutic agent. Citation Format: Dinesh K. Ahirwar, Nabanita Chatterjee, Sanjay Mishra, Kontestine Shilo, Ramesh Ganju. Slit2 inhibits breast cancer growth and metastasis by activating anti-tumor immune response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4561.

Increases in Tumor N-Glycan Polylactosamines Associated with Advanced HER2-Positive and Triple-Negative Breast Cancer Tissues.

Using a recently developed matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS) method, human breast cancer formalin-fixed paraffin-embedded (FFPE) tissue sections and tissue microarrays (TMA) are evaluated for N-linked glycan distribution in the tumor microenvironment. Tissue sections representing multiple human epidermal growth factor receptor 2 (HER2) receptor-positive and triple-negative breast cancers (TNBC) in both TMA and FFPE slide format are processed for high resolution N-glycan MALDI-IMS. An additional FFPE tissue cohort of primary and metastatic breast tumors from the same donors are also evaluated. The cumulative N-glycan MALDI-IMS analysis of breast cancer FFPE tissues and TMAs indicate the distribution of specific glycan structural classes to stromal, necrotic, and tumor regions. A series of high-mannose, branched and fucosylated glycans are detected predominantly within tumor regions. Additionally, a series of polylactosamine glycans are detected in advanced HER2+, TNBC, and metastatic breast cancer tissues. Comparison of tumor N-glycan species detected in paired primary and metastatic tissues indicate minimal changes between the two conditions. The prevalence of tumor-associated polylactosamine glycans in primary and metastatic breast cancer tissues indicates new mechanistic insights into the development and progression of breast cancers. The presence of these glycans could be targeted for therapeutic strategies and further evaluation as potential prognostic biomarkers.

Increased Expression of CD81 in Breast Cancer Tissue is Associated with Reduced Patient Prognosis and Increased Cell Migration and Proliferation in MDA-MB-231 and MDA-MB-435S Human Breast Cancer Cell Lines In Vitro.

BackgroundCD81, a member of the tetraspanin family, is overexpressed in several tumor types, but its role in breast cancer remains unknown. The present study aimed to investigate the effects of increased CD81 expression on cell migration and proliferation in breast cancer cell lines, MDA-MB-231 and MDA-MB-435S in vitro, and the effects of increased CD81 expression in breast cancer tissue microarrays on patient prognosis.Material/MethodsThe expression of CD81 was evaluated using immunohistochemistry in a human breast cancer tissue microarray containing 140 tumor tissues and a microarray containing 77 normal breast tissues. The effects of increased CD81 expression on cell proliferation and migration in breast cancer cell lines, MDA-MB-231 and MDA-MB-435S, were evaluated by proliferation, transwell migration, and cell counting kit-8 (CCK-8) assays. CD81-expressing plasmid transfection upregulated CD81 expression, and short hairpin RNA (shRNA) lentivirus silenced CD81 expression in vitro.ResultsCD81 expression was significantly increased in breast cancer tissues compared with normal breast tissues (P<0.05). Increased expression of CD81 was significantly associated with lymph node metastasis (P<0.05), clinical stage (P<0.05) and with reduced overall survival (OS) in patients with breast cancer (P<0.05). Increased CD81 expression in MDA-MB-231 and MDA-MB-435S cells promoted cell proliferation and migration, which were inhibited by CD81 silencing.ConclusionsThe findings of the study showed that CD81 might be a potential prognostic biomarker associated with poor patient prognosis in breast cancer. These findings should be investigated further with large-scale controlled prospective studies in patients with breast cancer.

Abstract B52: HIF-ZMYND8-BRD4 axis mediates breast cancer progression and metastasis

Abstract Metastatic breast cancer is lethal and incurable. The major obstacle to ending this aggressive disease is the absence of definitive prognostic biomarker and effective therapeutic target. Epigenetic dysregulation plays a crucial role in breast cancer metastasis. However, how epigenetic dysregulation under tumor hypoxia stimulates breast cancer progression and metastasis remains unknown. We recently identified the epigenetic reader ZMYND8 as a novel HIF target gene by analyzing expression changes of 720 epigenetic genes in three microarray gene expression and mRNA sequencing datasets. Analysis of a human breast cancer tissue microarray revealed that ZMYND8 is highly expressed in invasive breast tumors and high levels of ZMYND8 are significantly correlated with poor clinical outcomes in patients with breast cancer. ZMYND8 depletion significantly suppresses colony formation, invasion, and migration of breast cancer cells in vitro, and inhibits breast tumor growth and metastasis in mice. To figure out the underlying mechanism, we performed co-immunoprecipitation, chromatin immunoprecipitation, and quantitative PCR assays and found that ZMYND8 interacts with HIF complex and acetyl lysine 16 of histone H3 at the hypoxia response elements (HREs) to stimulate the expression of HIF target genes LOX, AGR2, AQP1, and VEGFA. HIF is required for ZMYND8-mediated breast cancer growth and metastasis in mice. We further found that p300 binds and acetylates ZMYND8 in breast cancer cells. Acetylated ZMYND8 interacts with the bromodomains of BRD4 and recruits BRD4 to the HREs to stimulate RNA polymerase II phosphorylation and subsequent transcriptional elongation of HIF target genes. ZMYND8 acetylation is necessary and sufficient for breast tumor growth and metastasis in vitro and in mice. Together, these findings indicate that p300-acetylated ZMYND8 mediates breast cancer progression and metastasis by BRD4-dependent activation of HIF. In summary, ZMYND8 represents a positive-feedback mechanism that amplifies HIF-mediated breast cancer progression and metastasis, and may be a potential epigenetic target for the prognosis and treatment of breast cancer. Citation Format: Yan Chen, Bo Zhang, Lei Bao, Lai Jin, Mingming Yang, Yan Peng, Jennifer Wang, Chenliang Wang, Xuan Zou, Yingfei Wang, Weibo Luo. HIF-ZMYND8-BRD4 axis mediates breast cancer progression and metastasis [abstract]. In: Proceedings of the AACR Special Conference: Advances in Breast Cancer Research; 2017 Oct 7-10; Hollywood, CA. Philadelphia (PA): AACR; Mol Cancer Res 2018;16(8_Suppl):Abstract nr B52.

Abstract 82: Epigenetic reader ZMYND8 bridges BRD4 and hypoxia-inducible factors to mediate breast cancer progression and metastasis

Abstract Metastatic breast cancer has high rates of relapse and mortality. The absence of definitive prognostic biomarker and effective therapeutic target is the major obstacle to end this aggressive disease. Epigenetic dysregulation plays a crucial role in breast cancer metastasis. However, the mechanism by which epigenetic dysregulation stimulates the hypoxia-mediated breast cancer progression and metastasis remains unknown. Based on luciferase reporter assays and analysis of expression changes of 720 epigenetic genes in three microarray datasets, we identified epigenetic reader ZMYND8 as a novel hypoxia-inducible factor (HIF) target gene. Human breast cancer tissue microarray data indicated that ZMYND8 is highly expressed in invasive breast tumors and this overexpression is significantly correlated with poor clinical outcomes in patients with breast cancer. ZMYND8 depletion dramatically attenuates the tumorigenic potential of breast cancer cells in colony formation, migration and invasion in vitro, and suppresses breast tumor growth and metastasis in mice. To elucidate the underlying mechanism, we performed co-immunoprecipitation, chromatin immunoprecipitation and quantitative PCR assays and found that ZMYND8 interacts with HIF complex and acetyl lysine 16 of histone H3 at the hypoxia inducible elements (HREs) to provoke the expression of HIF target genes LOX, AGR2, AQP1 and VEGFA. ZMYND8 controls breast cancer growth and metastasis through HIF in mice. We further found that p300 binds and acetylates ZMYND8 in breast cancer cells. Acetylated ZMYND8 interacts with and recruits BRD4 to the HREs to stimulate RNA polymerase II phosphorylation, thereby promoting transcriptional elongation of HIF target genes. ZMYND8 acetylation is necessary and sufficient for breast tumor growth and metastasis in vitro and in mice. Together, p300-ZMYND8-BRD4-HIF axis is critical for breast cancer progression and metastasis. In summary, ZMYND8 represents a positive feedback mechanism that amplifies HIF-mediated breast cancer progression and metastasis, and provides a potential epigenetic target for the prognosis and treatment of breast cancer. Citation Format: Yan Chen, Bo Zhang, Lei Bao, Lai Jin, Mingming Yang, Yan Peng, Jennifer Wang, Chenliang Wang, Xuan Zou, Yingfei Wang, Weibo Luo. Epigenetic reader ZMYND8 bridges BRD4 and hypoxia-inducible factors to mediate breast cancer progression and metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 82.

Infiltration of γ⁢δ T cells, IL-17+ T cells and FoxP3+ T cells in human breast cancer.

BACKGROUND: Tumor-infiltrating lymphocytes (TILs) have a strong prognostic value in various forms of cancers. These data often refer to use of the pan-T cell marker CD3, or the cytotoxic T lymphocyte marker CD8. However, T cells are a heterogeneous group of cells with a wide array of effector mechanisms ranging from immunosuppression to cytotoxicity.OBJECTIVE: In this study we have investigated the prognostic effects of some unconventional T cell subtypes in breast cancer; T cells, IL-17 T cells and FoxP3 T cells (T) in relation to the conventional CD3 and CD8 T cell markers.METHODS: This was done using immunohistochemistry on a human breast cancer tissue microarray consisting of 498 consecutive cases of primary breast cancer.RESULTS: Infiltration of T cells and T cell infiltration in general (CD3), correlated with a good prognosis, while T infiltration with a worse. Infiltration of T cells was associated with a significantly improved clinical outcome in all breast cancer subtypes except triple negative tumors. Only infiltration of either CD3 or CD8 cells was independently associated with better prognosis for all breast cancer patients.CONCLUSIONS: This study sheds further light on the prognostic impact of various T cell subtypes in breast cancer.

Chaperonin Containing TCP-1 Protein Level in Breast Cancer Cells Predicts Therapeutic Application of a Cytotoxic Peptide.

Metastatic disease is a leading cause of death for patients with breast cancer, driving the need for new therapies. CT20p is a peptide previously discovered by our group that displays cancer-specific cytotoxicity. To design the optimal therapeutic use of the peptide, we identified the intracellular target of CT20p in breast cancer cells, correlating expression patterns of the target with susceptibility to CT20p. Using polymeric nanoparticles to deliver CT20p, we assessed cytoskeletal changes, cell migration, adhesion, and viability in cells treated with the peptide. Protein pull-down experiments, coupled to mass spectrometry, enabled identification of the peptide's intracellular target. Biochemical and histologic techniques validated target identity in human cell lines and breast cancer tissue microarrays and revealed susceptibility patterns to CT20p. Chaperonin containing TCP-1 (CCT) was identified as the intracellular target of CT20p. Cancer cells susceptible to CT20p had increased CCT, and overexpression of CCTβ, a subunit of the CCT complex, enhanced susceptibility to CT20p. Susceptible cells displayed reduced tubulin, a substrate of CCT, and inhibition of migration upon CT20p treatment. CCTβ levels were higher in invasive ductal carcinomas than in cancer adjacent tissues and increased with breast cancer stage. Decreased breast cancer patient survival correlated with genomic alternations in CCTβ and higher levels of the chaperone. Increased CCT protein in breast cancer cells underlies the cytotoxicity of CT20p. CCT is thus a potential target for therapeutic intervention and serves as a companion diagnostic to personalize the therapeutic use of CT20p for breast cancer treatment. Clin Cancer Res; 22(17); 4366-79. ©2016 AACR.

A dual prognostic role for the TGFβ receptors in human breast cancer

The transforming growth factor-β (TGFβ) plays a dual role in breast cancer, acting as a tumor suppressor in early carcinomas while promoting tumor metastasis in more advanced breast carcinoma. As a result, the prognostic role of TGFβ and its signaling components in breast cancer remains unclear. Here we evaluated the expression levels of TGFβ signaling receptors TβRII and TβRI using human breast cancer tissue microarrays and a large publicly available gene profiling database in relation to various clinicopathological parameters. Our results indicate that breast cancer tissues express lower TβRII and TβRI protein levels compared with normal breast tissue. In contrast to TβRI expression, TβRII mRNA expression levels were also significantly downregulated in invasive breast cancer compared with normal breast tissue (4.18-fold downregulation, P=9.3×10-115). Interestingly, within the cancer cases analyzed, our results revealed a direct correlation between high TβRII and TβRI expression levels and classic poor prognostic clinicopathological parameters, including larger tumor size, advanced tumor stage, and poorly differentiated tumors. Next, we examined TGFβ receptors' expression in relation to breast cancer molecular subtypes. Importantly, our results revealed that whereas expression of TGFβ receptors in luminal A and triple-negative breast cancer showed no correlation with patient outcome, their expression in luminal B and HER2 subtypes showed significant association with favorable patient outcome. Together, these results indicate that although TGFβ receptors are downregulated in breast cancer, their expression in tumors is an indicator of aggressive breast cancer phenotype. Moreover, the relation between TGFβ pathway and patient outcome is breast cancer subtype dependent.