Breast Cancer Tumor Microenvironment Research Articles

CD74 promotes the formation of an immunosuppressive tumor microenvironment in triple-negative breast cancer in mice by inducing the expansion of tolerogenic dendritic cells and regulatory B cells.

CD74 is a cell-surface receptor for the cytokine macrophage migration inhibitory factor (MIF). MIF binding to CD74 induces a signaling cascade resulting in the release of its cytosolic intracellular domain (CD74-ICD), which regulates transcription in naïve B and chronic lymphocytic leukemia (CLL) cells. In the current study, we investigated the role of CD74 in the regulation of the immunosuppressive tumor microenvironment (TME) in triple-negative breast cancer (TNBC). TNBC is the most aggressive breast cancer subtype and is characterized by massive infiltration of immune cells to the tumor microenvironment, making this tumor a good candidate for immunotherapy. The tumor and immune cells in TNBC express high levels of CD74; however, the function of this receptor in the tumor environment has not been extensively characterized. Regulatory B cells (Bregs) and tolerogenic dendritic cells) tol-DCs (were previously shown to attenuate the antitumor immune response in TNBC. Here, we demonstrate that CD74 enhances tumor growth by inducing the expansion of tumor-infiltrating tol-DCs and Bregs. Utilizing CD74-KO mice, Cre-flox mice lacking CD74 in CD23+ mature B cells, mice lacking CD74 in the CD11c+ population, and a CD74 inhibitor (DRQ), we elucidate the mechanism by which CD74 inhibits antitumor immunity. MIF secreted from the tumor cells activates CD74 expressed on DCs. This activation induces the binding of CD74-ICD to the SP1 promotor, resulting in the up-regulation of SP1 expression. SP1 binds the IL-1β promotor, leading to the down-regulation of its transcription. The reduced levels of IL-1β lead to decreased antitumor activity by allowing expansion of the tol-DC, which induces the expansion of the Breg population, supporting the cross-talk between these 2 populations. Taken together, these results suggest that CD74+ CD11c+ DCs are the dominant cell type involved in the regulation of TNBC progression. These findings indicate that CD74 might serve as a novel therapeutic target in TNBC.

Mutual information for detecting multi-class biomarkers when integrating multiple bulk or single-cell transcriptomic studies.

Biomarker detection plays a pivotal role in biomedical research. Integrating omics studies from multiple cohorts can enhance statistical power, accuracy and robustness of the detection results. However, existing methods for horizontally combining omics studies are mostly designed for two-class scenarios (e.g., cases versus controls) and are not directly applicable for studies with multi-class design (e.g., samples from multiple disease subtypes, treatments, tissues, or cell types). We propose a statistical framework, namely Mutual Information Concordance Analysis (MICA), to detect biomarkers with concordant multi-class expression pattern across multiple omics studies from an information theoretic perspective. Our approach first detects biomarkers with concordant multi-class patterns across partial or all of the omics studies using a global test by mutual information. A post hoc analysis is then performed for each detected biomarkers and identify studies with concordant pattern. Extensive simulations demonstrate improved accuracy and successful false discovery rate control of MICA compared to an existing MCC method. The method is then applied to two practical scenarios: four tissues of mouse metabolism-related transcriptomic studies, and three sources of estrogen treatment expression profiles. Detected biomarkers by MICA show intriguing biological insights and functional annotations. Additionally, we implemented MICA for single-cell RNA-Seq data for tumor progression biomarkers, highlighting critical roles of ribosomal function in the tumor microenvironment of triple-negative breast cancer and underscoring the potential of MICA for detecting novel therapeutic targets. The source code is available on Figshare at https://doi.org/10.6084/m9.figshare.27635436. Additionally, the R package can be installed directly from GitHub at https://github.com/jianzou75/MICA. Supplementary data are available at Bioinformatics online.

Abstract C016: Age dictates immune response within the tumor microenvironment of triple negative breast cancer

Abstract Age is the biggest risk factor for developing most forms of cancer. In breast cancer, over 50% of patients are over 60 years old; however, less than 25% of patients enrolled in clinical trials are in this age bracket. Furthermore, most mouse modeling is performed in young mice, meaning that from preclinical through clinical stages patients ages are not accurately reflected in trials designs. Triple negative breast cancer (TNBC) is an aggressive subtype of breast cancer with no targeted therapies, so many treatment strategies utilize chemotherapy in combination with immunotherapy – which relies on a functional immune response. It is well known that immune function declines as we age, and thus therapeutic responses may differ with age. It is yet unclear how the tumor immune microenvironment changes with age, and how this may impact therapeutic response. Here, we utilize a mouse model which mimics hallmarks of human immune aging to understand how age impacts TNBC immune responses to dictate disease progression and therapeutic response. Immunologically young (8 weeks old) and aged (∼12 months old) FVB mice were orthotopically injected with syngeneic Met1 TNBC cells. Once tumors became palpable, mice were treated with paclitaxel chemotherapy or vehicle control and/or anti-PDL1 immunotherapy to mimic first-line therapeutic strategies. Tumors grew significantly faster in young control mice compared to aged, but young mice had a more robust response to therapy. Notable, only young mice had a significant benefit of combo therapy over monotherapy alone. Despite aged mice having more circulating CD8+ and CD4+ T cells, tumors in aged mice had significantly more infiltration of CD8+ cytotoxic T cells and FOXP3+ inhibitory T-regulatory cells compared to young control mice, yet only tumors in young mice exhibited an increase in T cell infiltration with therapy. Additionally, the ratio of CD8+ T cells and FOXP3+ Tregs was unchanged with age or treatment. Depletion of either CD8+ or CD4+ T cells led to a complete loss of age-associated differences in tumor growth. RNA sequencing analysis suggests that infiltrating T cells in aged mice may be exhausted due to a chronic interferon (IFN) phenotype, indicated by enrichment of IFN-alpha, IFN-gamma, and IL2 pathways, as well as increased expression of immune exhaustion markers PD1, CTLA4, TIM3 and LAG3. Neutralization of IFN-gamma blocks therapeutic response to anti-PDL1 in young mice but has no impact on aged mice. Analysis of published single cell RNAseq data indicated the same IFN response pathways enriched with age in human TNBC. These results demonstrate that the aging tumor immune microenvironment significantly impacts tumor progression and therapeutic response and suggest that targeting IFN signaling may lead to improved therapeutic responses. Together these findings establish a significant impact of immune aging on TNBC disease progression and response to therapy, highlighting the importance of developing age- stratified treatment strategies to improve responses in patients of all ages. Citation Format: Milos Spasic, Adrienne Parsons, Abigail Recko, Elizabeth Mittendorf, Peter van Galen, Sandra McAllister. Age dictates immune response within the tumor microenvironment of triple negative breast cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr C016.

Abstract C032: The impact of neoadjuvant endocrine therapy (NET) in ER+ breast cancer tumor microenvironment and metastasis

Abstract Breast cancer is the most common cancer in women worldwide and the second leading cause of death. The Estrogen Receptor positive (ER+) subtype constitutes approximately 80% of the yearly 250,000 breast cancer diagnoses in the US. Anti-estrogen endocrine therapy, administered either pre- or post-operatively, is the cornerstone treatment for all stages of breast cancer. Pre- operative or neoadjuvant endocrine therapy (NET) reduces pre-surgical tumor burden, improves surgical outcome, and provides prognostic information. Although the treatment often has a favorable initial response, about 20% of patients eventually develop resistance and recurrent disease, even decades after the primary diagnosis.We hypothesized that resistance in NET is mediated through pro-metastatic changes in the tumor microenvironment affecting either (i) dissemination machinery or (ii) cancer cell phenotype.The main mode of breast cancer hematogenous dissemination to distant sites is through intravasation portals called Tumor Microenvironment of Metastasis (TMEM) doorways. Each TMEM doorway consists of a tumor cell overexpressing the actin-regulatory protein MENA, a Tie2high/ VEGFAhigh macrophage and an endothelial cell, all in direct contact. TMEM doorway activity leads to vascular opening events, during which tumor cells located in areas around TMEM doorways intravasate and disseminate to secondary sites. Therefore, to investigate the impact of NET on cancer cell dissemination, we evaluated its effect on (i) TMEM doorway score (the number of TMEM doorways per tissue area), (ii) TMEM doorway opening, (iii) the number of circulating tumor cells and (iv) the number of disseminated tumor cells. We used the orthotopic MCF7 breast cancer xenograft model grown in NOD/SCID mice and tested two drugs widely used in NET, Fulvestrant (a Selective Estrogen Receptor Degrader) and Tamoxifen (a Selective Estrogen Receptor Modulator). NET did not affect the TMEM doorway score, TMEM doorway activity, the number of CTCs or the number of DTCs. We are now focused on evaluating the effect of NET on the density of cancer cells which are upregulated in programs of invasion, stemness, and dormancy. This “Triple Threat Phenotype (TTP)” gives tumor cells an enhanced ability to disseminate to and colonize distant organs. To this effect we will stain primary MCF7 tumors from NET and vehicle-treated mice for markers of invasiveness (MENA), stemness (SOX9) and dormancy (NR2F1). Detecting any changes in the phenotype of metastatic tumor cells following NET will help us understand underlying mechanisms of endocrine therapy resistance and may lead to new therapeutic targets and improve patient outcomes. Citation Format: Anastasia Aristoteleia Chondronikola, Dimitra Anastasiadou, Aliona Zintiridou, Camille L. Duran, Nicole Barth, Burcu Karadal-Ferrena, Erika Pereira-Zambalde, Lina Ariyan, Suryansh Shukla, George S. Karagiannis, David Entenberg, John S. Condeelis, Maja H. Oktay. The impact of neoadjuvant endocrine therapy (NET) in ER+ breast cancer tumor microenvironment and metastasis [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr C032.

Abstract B031: Lean adipocyte-derived lipid decreases metastatic potential of breast cancer cells

Abstract Obesity rates are increasing globally, making it of critical importance to study obesity-linked diseases. Breast cancer is the most common cancer in women, and obesity is associated with both increased incidence and metastatic progression of breast cancer. Metastasis formation depends on a cancer cell leaving the primary site, migrating through the bloodstream, and establishing new growth in a distant site. Both metastasizing cell-intrinsic and metastatic site-dependent factors can help to regulate the effectiveness of this process; however, it is unknown whether obesity-linked metastasis depends on changes to the metastasizing cell and/or changes to the distant metastatic site. This study aims to characterize how the lean versus obese tumor microenvironment impacts breast cancer metastasis and identify adipocyte-derived molecules that modulate the metastatic potential of breast cancer cells. We and others have shown that obesity leads to increased metastasis formation in mouse models of orthotopic breast cancer. However, my preliminary data show that an obese metastatic site is not sufficient to increase metastasis formation in an intravenous injection model of metastasis, emphasizing the importance of the primary tumor microenvironment in programming breast cancer cells for metastasis. Cancer cell stemness helps to mediate metastasis formation and can be assessed in vitro with the mammosphere assay. Importantly, my data demonstrate that a secreted lipid from lean, but not obese, adipocytes potently inhibits the ability of breast cancer cells to form mammospheres. Furthermore, this inhibition induces a G1/S cell cycle arrest. Together, these data suggest that lean adipocytes in the breast cancer tumor microenvironment act in a paracrine manner to decrease the metastatic potential of breast cancer cells. My work demonstrates the role of adipocytes in the regulation of metastasis in breast cancer and provides important insight into the role of the tumor microenvironment in mediating metastasis in lean versus obese conditions. Citation Format: Abigail E. Jackson, Keren I Hilgendorf. Lean adipocyte-derived lipid decreases metastatic potential of breast cancer cells [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr B031.

Prognostic and immune correlation of IDO1 promoter methylation in breast cancer

Indoleamine 2,3-dioxygenase 1 (IDO1) plays an important role in the initiation and progression of breast cancer. DNA promoter methylation status has the potential to be used as a biomarker for predicting the response to immunotherapy. This study aimed to investigate the biological and clinical significance of IDO1 promoter methylation in breast cancer. We analyzed IDO1 promoter methylation and its relationship with survival, patient prognosis, immune cell infiltration, immune-related pathways, and the expression of key immunomodulators via bioinformatics methods in The Cancer Genome Atlas (TCGA) breast cancer cohort (779 samples). Furthermore, the IDO1 promoter methylation status and expression of the IDO1 gene in the basal subtype of breast cancer were investigated in vitro via a methylation-specific PCR (MSP) assay and quantitative polymerase chain reaction (qPCR). The IDO1 promoter was significantly hypomethylated in the basal subtype of breast cancer tissues compared with normal adjacent tissues, and this effect was correlated with high expression of IDO1, resulting in abundant immune cell infiltration, activation of immune-related pathways, and upregulation of key immunomodulators. The influence of IDO1 promoter hypomethylation on the prognosis of patients with breast cancer was also investigated. The promoter hypomethylation of IDO1 in the basal subtype of breast cancer and its correlation with high expression of IDO1 were also investigated in vitro. Our results showed that IDO1 promoter methylation is vital for regulating its expression, which leads to the development of a tumor microenvironment in breast cancer. IDO1 promoter methylation and expression are associated with prognosis, immune cell infiltration, immune-related pathways, and immunomodulator expression in breast cancer. Our findings provide evidence for the validation of IDO1 promoter methylation as a promising biomarker to predict responses to immune checkpoint inhibitors in patients with breast cancer.

Integration of Machine Learning and Experimental Validation to Identify Anoikis-Related Prognostic Signature for Predicting the Breast Cancer Tumor Microenvironment and Treatment Response.

Background/Objectives: Anoikis-related genes (ANRGs) are crucial in the invasion and metastasis of breast cancer (BC). The underlying role of ANRGs in the prognosis of breast cancer patients warrants further study. Methods: The anoikis-related prognostic signature (ANRS) was generated using a variety of machine learning methods, and the correlation between the ANRS and the tumor microenvironment (TME), drug sensitivity, and immunotherapy was investigated. Moreover, single-cell analysis and spatial transcriptome studies were conducted to investigate the expression of prognostic ANRGs across various cell types. Finally, the expression of ANRGs was verified by RT-PCR and Western blot analysis (WB), and the expression level of PLK1 in the blood was measured by the enzyme-linked immunosorbent assay (ELISA). Results: The ANRS, consisting of five ANRGs, was established. BC patients within the high-ANRS group exhibited poorer prognoses, characterized by elevated levels of immune suppression and stromal scores. The low-ANRS group had a better response to chemotherapy and immunotherapy. Single-cell analysis and spatial transcriptomics revealed variations in ANRGs across cells. The results of RT-PCR and WB were consistent with the differential expression analyses from databases. NU.1025 and imatinib were identified as potential inhibitors for SPIB and PLK1, respectively. Additionally, findings from ELISA demonstrated increased expression levels of PLK1 in the blood of BC patients. Conclusions: The ANRS can act as an independent prognostic indicator for BC patients, providing significant guidance for the implementation of chemotherapy and immunotherapy in these patients. Additionally, PLK1 has emerged as a potential blood-based diagnostic marker for breast cancer patients.

Biomaterials' enhancement of immunotherapy for breast cancer by targeting functional cells in the tumor micro-environment.

Immunotherapy for breast cancer is now being considered clinically, and more recently, the number of investigations aimed specifically at nano-biomaterials-assisted immunotherapy for breast cancer treatment is growing. Alterations of the breast cancer micro-environment can play a critical role in anti-tumor immunity and cancer development, progression and metastasis. The improvement and rearrangement of tumor micro-environment (TME) may enhance the permeability of anti-tumor drugs. Therefore, targeting the TME is also an ideal and promising option during the selection of effective nano-biomaterial-based immuno-therapeutic strategies excepted for targeting intrinsic resistant mechanisms of the breast tumor. Although nano-biomaterials designed to specifically release loaded anti-tumor drugs in response to tumor hypoxia and low pH conditions have shown promises and the diversity of the TME components also supports a broad targeting potential for anti-tumor drug designs, yet the applications of nano-biomaterials for targeting immunosuppressive cells/immune cells in the TME for improving the breast cancer treating outcomes, have scarcely been addressed in a scientific review. This review provides a thorough discussion for the application of the different forms of nano-biomaterials, as carrier vehicles for breast cancer immunotherapy, targeting specific types of immune cells in the breast tumor microenvironment. In parallel, the paper provides a critical analysis of current advances/challenges with leading nano-biomaterial-mediated breast cancer immunotherapeutic strategies. The current review is timely and important to the cancer research field and will provide a critical tool for nano-biomaterial design and research groups pushing the clinical translation of new nano-biomaterial-based immuno-strategies targeting breast cancer TME, to further open new avenues for the understanding, prevention, diagnosis and treatment of breast cancer, as well as other cancer types.

Exploring Tumor Microenvironment in Breast Cancer: Parameters that can be Assessed with Light Microscopy.

Exploring Tumor Microenvironment in Breast Cancer: Parameters that can be Assessed with Light Microscopy.

Delivery of IL2RG mRNA via nanoparticles to enhance CD8+ T cell promotes anti-tumor effects against late-stage triple-negative breast cancer

BackgroundThe manipulation of CD8+ T cell functions through genetic modifications presents a novel approach to cancer immunotherapy. This study aimed to explore the effects of IL2RG-overexpressing CD8+ T cells and assess the efficacy of delivering IL2RG mRNA via nanoparticles (NPs) to the tumor microenvironment in triple-negative breast cancer (TNBC).MethodsSingle-cell RNA sequencing (scRNA-seq) was conducted on tissue from early and late-stage TNBC, followed by a meta-analysis of six breast cancer arrays from the GEO database to identify candidate genes. CRISPR/Cas9 was employed for gene knockout and overexpression in CD8+ T cells, which were then analyzed using flow cytometry, ELISA, immunofluorescence, and metabolic assays. A 3D cancer cell spheroid model was used for co-culture experiments. Lipid-coated calcium-phosphate (LCP)@IL2RG NPs were synthesized and injected into TNBC mouse models.ResultsIL2RG was identified as significantly associated with late-stage TNBC. Overexpression of IL2RG in CD8+ T cells led to increased cell activation, cytotoxicity, and glycolysis, while knockout reduced these effects. Overexpressing IL2RG in CD8+ T cells co-cultured with 3D cancer spheroids resulted in enhanced apoptosis and reduced cancer cell invasion. Injection of LCP@IL2RG NPs into TNBC mouse models significantly mitigated tumor growth.ConclusionsOverexpressing IL2RG in CD8+ T cells enhances tumor immunotherapy. Delivering IL2RG mRNA via NPs further amplifies this effect, offering a promising strategy for the treatment of late-stage TNBC.

Enhanced docetaxel therapeutic effect using dual targeted SRL-2 and TA1 aptamer conjugated micelles in inhibition Balb/c mice breast cancer model

Effective targeting and delivery of large amounts of medications into the cancer cells enhance their therapeutic efficacy through saturation of cellular defensive mechanisms, which is the most privilege of nano drug delivery systems (NDDS) compared to traditional approaches. Herein, we designed dual-pH/redox responsive DTX-loaded poly (β-amino ester) (PBAS) micelles decorated with a chimeric peptide and TA1 aptamer. In vitro and in vivo results demonstrated that the designed nanoplatform possessed an undetectable nature in the blood circulation, but after exposure to the tumor microenvironment (TME) of 4T1 breast cancer, it suddenly changed into dual targeting nanoparticles (NPs) (containing two ligands, SRL-2 and TA1 aptamer). The dual targeting NPs destruction in the high GSH and low pH conditions of the cancer cells led to amplified DTX release (around 70% at 24 h). The IC50 value of DTX-loaded MMP-9 sensitive heptapeptide/TA1 aptamer-modified poly (β-amino ester) (MST@PBAS) micelles and free DTX after 48 h of exposure was determined to be 1.5 µg/ml and 7.5 µg/ml, respectively. The nano-formulated DTX exhibited cytotoxicity that was 5-fold stronger than free DTX (Pvalue˂0.001). Cell cycle assay test results showed that following exposure to MST@PBAS micelles, a considerable rise in the sub G1 population (48%) suggested that apoptosis by cell cycle arrest had occurred. DTX-loaded MST@PBAS micelles revealed significantly higher (Pvalue ˂ 0.001) levels of early apoptosis (59.8%) than free DTX (44.7%). Interestingly, in vitro uptake studies showed a significantly higher TME accumulation of dual targeted NPs (6-fold) compared to single targeted NPs (Pvalue < 0.001) which further confirmed by in vivo biodistribution and fluorescent TUNEL assay experiments. NPs treated groups demonstrated notable tumor growth inhibition in 4T1 tumor bearing Balb/c mice by only 1/10th of the DTX therapeutic dose (TD) as a drug model. In conclusion, cleverly designed nanostructures here demonstrated improved anticancer effects by enhancing tumor targeting, delivering chemotherapeutic agents more accurately, promoting drug release, reducing the therapeutic dosage, and lowering side effects of anticancer drugs.

Histologic Characterization of Tumor-Adjacent Mammary Adipose Tissue in Normal-Weight and Overweight/Obese Patients with Triple-Negative Breast Cancer

Background: Obesity is a risk factor of several types of cancer, including breast cancer. In this study, we aimed to histologically characterize the adipose tissue of the tumor microenvironment (TME) of triple-negative breast cancer (TNBC) in overweight/obese versus normal-weight patients. Methods: TNBC tissue sections from normal-weight (BMI&lt;25) and overweight/obese patients (BMI≥25) were stained with antibodies against CD68, CD163, CD31, CD34, and vimentin. At the invasive tumor front, positive cells were counted in tumor adjacent adipose tissue (AT) and within cancer tissue (CT). Further, the size of the tumor-adjacent and distant mammary adipocytes was determined in perilipin stained sections. Expression of ANGPTL4, CD36 and FABP4, proteins involved in fatty acid metabolism, was analyzed in marginal tumor cells using an immune reactive score. Results: Overweight/obese TNBC patients had significantly larger adipocytes, higher numbers of CD163+ macrophages (BMI&lt;25: 2.80 vs. BMI≥25: 10.45; p = 0.011) and lower numbers of CD31+ (BMI&lt;25: 4.20 vs. BMI≥25: 2.40; p = 0.018) and CD34+ (BMI&lt;25: 14.60 vs. BMI≥25: 5.20; p = 0.045) cells as markers of angiogenesis in the AT as well as a higher frequency of cancer-associated-fibroblast-like cells in the AT and CT (BMI&lt;25: 7.60 vs. BMI≥25: 25.39 in total; p = 0.001). Moreover, expression of CD36 (BMI&lt;25: 2.15 vs. BMI≥25: 2.60; p = 0.041) and ANGPTL4 (BMI&lt;25: 6.00 vs. BMI≥25: 9.80; p = 0.026) was elevated in the TNBC cells of overweight/obese patients. Conclusions: Our data suggest BMI-related changes in the TME of overweight/obese TNBC patients, including hypertrophied adipocytes, reduced vascularization, more M2-like macrophages and CAF-like cells, and an increase in the expression of fatty acid metabolizing proteins in marginal tumor cells, all contributing to a more tumor-promoting, immunosuppressive environment.

Retraction Note: Tumor microenvironment and immune system preservation in early-stage breast cancer: routes for early recurrence after mastectomy and treatment for lobular and ductal forms of disease

Retraction Note: Tumor microenvironment and immune system preservation in early-stage breast cancer: routes for early recurrence after mastectomy and treatment for lobular and ductal forms of disease

Prognostic Impact of Acute and Chronic Inflammatory Interleukin Signatures in the Tumor Microenvironment of Early Breast Cancer

Interleukins play dual roles in breast cancer, acting as both promoters and inhibitors of tumorigenesis within the tumor microenvironment, shaped by their inflammatory functions. This study analyzed the subtype-specific prognostic significance of an acute inflammatory versus a chronic inflammatory interleukin signature using microarray-based gene expression analysis. Correlations between these interleukin signatures and immune cell markers (CD8, IgKC, and CD20) and immune checkpoints (PD-1) were also evaluated. This study investigated the prognostic significance of an acute inflammatory IL signature (IL-12, IL-21, and IFN-γ) and a chronic inflammatory IL signature (IL-4, IL-5, IL-10, IL-13, IL-17, and CXCL1) for metastasis-free survival (MFS) using Kaplan–Meier curves and Cox regression analyses in a cohort of 461 patients with early breast cancer. Correlations were analyzed using the Spearman–Rho correlation coefficient. Kaplan–Meier curves revealed that the prognostic significance of the acute inflammatory IL signature was specifically pronounced in the basal-like subtype (p = 0.004, Log Rank). This signature retained independent prognostic significance in multivariate Cox regression analysis (HR 0.463, 95% CI 0.290–0.741; p = 0.001). A higher expression of the acute inflammatory IL signature was associated with longer MFS. The chronic inflammatory IL signature showed a significant prognostic effect in the whole cohort, with higher expression associated with shorter MFS (p = 0.034). Strong correlations were found between the acute inflammatory IL signature and CD8 expression (ρ = 0.391; p &lt; 0.001) and between the chronic inflammatory IL signature and PD-1 expression (ρ = 0.627; p &lt; 0.001). This study highlights the complex interaction between acute and chronic inflammatory interleukins in breast cancer progression and prognosis. These findings provide insight into the prognostic relevance of interleukin expression patterns in breast cancer and may inform future therapeutic strategies targeting the immune–inflammatory axis.

8398 Non-genomic Effects of Thyroid Hormones on the Breast Cancer Microenvironment

Abstract Disclosure: L. Drago: None. S. Shahrivari: None. N. Schwenk: None. P. Nelson: None. H. Hosseini: None. C. Spitzweg: None. Objective: Mesenchymal stem cells (MSCs) are central players in the genesis of the breast cancer tumor microenvironment and play a role in tumor initiation, progression, invasion, metastasis, angiogenesis as well as resistance to treatment. There is increasing evidence for an association between thyroid function and breast cancer risk. Thyroid hormone effects mediated through the αvβ3 integrin, a thyroid hormone receptor, are proposed as a pathophysiologic link to this observation. Methods: To evaluate the migratory behavior of MSCs in the presence or absence of thyroid hormone treatment in response to tumor-derived signals, a 3D migration assay was performed. MSCs pretreated with T3 (1nM) or T4 (1μM) with or without tetrac (100nM) (T4 analog, specific inhibitor of αvβ3 integrin-mediated thyroid hormone action) for 24 h were subjected to a gradient between serum-free medium and serum-free conditioned medium (CM) from five different breast cancer cell lines representative of different breast cancer subtypes including T47D as Luminal B, MCF7 as Luminal A, BT-474 and MDA-MB-453 as HER2, and MDA-MB-231 as Triple negative subtype. Results: MSCs subjected to a gradient between CM derived from each breast cancer cell line and serum-free medium showed directed chemotaxis towards tumor-CM with a significantly increased forward migration index (FMI) and center of mass (CoM). This migratory behavior was significantly enhanced upon treatment with T3 or T4. The cellular migration towards tumor-CM of MDA-MB-453, BT-474, and T47D was more effective upon MSC treatment with T3, but less so with T4. MSCs treated with T4 showed a better migratory performance towards the CM of MCF7 and MDA-MB-231. Except for T47D-CM, additional treatment with tetrac inhibited the enhanced effects of T3 and T4 on MSC migration demonstrating that this effect is mediated through αvβ3 integrin. Conclusion: Our preliminary in vitro data on the effects of thyroid hormones T3 and T4, and the thyroid hormone metabolite tetrac on MSC migration shows a distinct behaviour of MSCs in the presence of either T3 or T4 depending on the breast cancer cell subtype, suggesting a role of non-genomic, integrin αvβ3-mediated thyroid hormone action on MSC biology within the breast tumor microenvironment that warrants further investigation. Presentation: 6/3/2024

8398 Non-genomic Effects Of Thyroid Hormones On The Breast Cancer Microenvironment

Abstract Disclosure: L. Drago: None. S. Shahrivari: None. N. Schwenk: None. P. Nelson: None. H. Hosseini: None. C. Spitzweg: None. Objective: Mesenchymal stem cells (MSCs) are central players in the genesis of the breast cancer tumor microenvironment and play a role in tumor initiation, progression, invasion, metastasis, angiogenesis as well as resistance to treatment. There is increasing evidence for an association between thyroid function and breast cancer risk. Thyroid hormone effects mediated through the αvβ3 integrin, a thyroid hormone receptor, are proposed as a pathophysiologic link to this observation. Methods: To evaluate the migratory behavior of MSCs in the presence or absence of thyroid hormone treatment in response to tumor-derived signals, a 3D migration assay was performed. MSCs pretreated with T3 (1nM) or T4 (1μM) with or without tetrac (100nM) (T4 analog, specific inhibitor of αvβ3 integrin-mediated thyroid hormone action) for 24 h were subjected to a gradient between serum-free medium and serum-free conditioned medium (CM) from five different breast cancer cell lines representative of different breast cancer subtypes including T47D as Luminal B, MCF7 as Luminal A, BT-474 and MDA-MB-453 as HER2, and MDA-MB-231 as Triple negative subtype. Results: MSCs subjected to a gradient between CM derived from each breast cancer cell line and serum-free medium showed directed chemotaxis towards tumor-CM with a significantly increased forward migration index (FMI) and center of mass (CoM). This migratory behavior was significantly enhanced upon treatment with T3 or T4. The cellular migration towards tumor-CM of MDA-MB-453, BT-474, and T47D was more effective upon MSC treatment with T3, but less so with T4. MSCs treated with T4 showed a better migratory performance towards the CM of MCF7 and MDA-MB-231. Except for T47D-CM, additional treatment with tetrac inhibited the enhanced effects of T3 and T4 on MSC migration demonstrating that this effect is mediated through αvβ3 integrin. Conclusion: Our preliminary in vitro data on the effects of thyroid hormones T3 and T4, and the thyroid hormone metabolite tetrac on MSC migration shows a distinct behaviour of MSCs in the presence of either T3 or T4 depending on the breast cancer cell subtype, suggesting a role of non-genomic, integrin αvβ3-mediated thyroid hormone action on MSC biology within the breast tumor microenvironment that warrants further investigation. Presentation: 6/3/2024

Impact of the tumor microenvironment of breast cancer on prognosis and treatment

According to world Health Organization, breast cancer (BC) ranks first among cancer diseases in women in many developed countries of the world and in the Russian Federation. Over the past 20 years, the incidence of breast cancer in the world has increased and continues to increase. This phenomenon dictates the need for a more in-depth molecular biological, genetic and immunological study of the mechanisms of development and progression of this heterogeneous malignant tumor.Recently, there has been increasing interest in the world not on lyin the direct causes of tumor development, but also in factors contributing to its progression, such as the cellular microenvironment of the tumor, the composition of which has a great influence on cancer development, treatment and prognosis. In the cellular microenvironment of the tumor, mononuclear cells are assessed, the proportion of which determines the severity and direction of the immuneresponse. Their importance for choosing the priority type of drug therapy and assessing its effectiveness is shown. The article provide scurrent data on subpopulations of T cells (CD8+, CD4+), B cells (CD20+), and natural killer. Their role in the development and progression of breast cancer is discussed depending on their phenotype. Modern research pays attention to a minor subpopulation of T lymphocytes – TCR-Vδ1+ cells. This subpopulation is represented predominantly in tumor tissue and has an immunosuppressive effect on T-effectors. At the present stage, inflammatory cells – macrophages and neutrophils – are of no less interest. Their role in tumor progression is widely debated. It is known that the differentiation of macrophages into M1 or M2 phenotypes is determined by the tumor microenvironment. The predominance of macrophages with protumor activity promotes tumor progression and cancer metastasis. Additionally, macrophages can stimulate the migration of neutrophils, which, in turn, support the metastasis of breast cancer through the production of matrix metalloproteinases. Matrix metalloproteinase 9 has been reported to promote the formation of vascular endothelial growth factor, which explains the protumor properties of neutrophils. In the context of growing tumor immunotherapy, assessment of tumor microenvironmental factors is promising both in relation to monitoring the effectiveness of breast cancer therapy and in relation to the search for potential therapeutic targets. The review systematizes and summarizes information on this issue to date.

Non-metabolic enzyme function of pyruvate kinase M2 in breast cancer.

Breast cancer (BC) is a prevalent malignant tumor in women, and its incidence has been steadily increasing in recent years. Compared with other types of cancer, it has the highest mortality and morbidity rates in women. So, it is crucial to investigate the underlying mechanisms of BC development and identify specific therapeutic targets. Pyruvate kinase M2 (PKM2), an important metabolic enzyme in glycolysis, has been found to be highly expressed in BC. It can also move to the nucleus and interact with various transcription factors and proteins, including hypoxia-inducible factor-1α (HIF-1α), signal transducer and activator of transcription 3 (STAT3), β-catenin, cellular-myelocytomatosis oncogene (c-Myc), nuclear factor kappa-light-chain enhancer of activated B cells (NF-κB), and mammalian sterile 20-like kinase 1 (MST1). This interaction leads to non-metabolic functions that control the cell cycle, proliferation, apoptosis, migration, invasion, angiogenesis, and tumor microenvironment in BC. This review provides an overview of the latest advancements in understanding the interactions between PKM2 and different transcription factors and proteins that influence the initiation and progression of BC. It also examined how natural drugs and noncoding RNAs affect various biological processes in BC cells through the regulation of the non-metabolic enzyme functions of PKM2. The findings provide valuable insights for improving the prognosis and developing targeted therapies for BC in the coming years.

Computational dissection of the regulatory mechanisms of aberrant metabolism in remodeling the microenvironment of breast cancer.

The composition of T cell subsets and tumor-specific T cell interactions within the tumor microenvironment (TME) contribute to the heterogeneity observed in breast cancer. Moreover, aberrant tumor metabolism is often intimately linked to dysregulated anti-tumor immune function of T cells. Identifying key metabolic genes that affect immune cell interactions thus holds promise for uncovering potential therapeutic targets in the treatment of breast cancer. This study leverages single-cell transcriptomic data from breast cancer to investigate tumor-specific T-cell subsets and their interacting subnetworks in the TME during cancer progression. We further assess the metabolic pathway activities of tumor-specifically activated T-cell subsets. The results reveal that metabolic pathways involved in insulin synthesis, secretion, degradation, as well as fructose catabolism, significantly influence multiple T cell interactions. By integrating the metabolic pathways that significantly up-regulate T cells in tumors and influence their interactions, we identify key abnormal metabolic genes associated with T-cell collaboration and further develop a breast cancer risk assessment model. Additionally, using gene expression profiles of prognosis-related genes significantly associated with aberrant metabolism and drug IC50 values, we predict targeted drugs, yielding potential candidates like GSK-J4 and PX-12. This study integrate the analysis of abnormal T-cell interactions and metabolic pathway abnormalities in the breast cancer TME, elucidating their roles in cancer progression and providing leads for novel breast cancer therapeutic strategies.

HSP90 promotes tumor associated macrophage differentiation during triple-negative breast cancer progression.

Tumor-associated macrophages (TAMs) originating from monocytes are crucial for cancer progression; however, the mechanism of TAM differentiation is unclear. We investigated factors involved in the differentiation of monocytes into TAMs within the tumor microenvironment of triple-negative breast cancer (TNBC). We screened 172 compounds and found that a heat shock protein 90 (HSP90) inhibitor blocked TNBC-induced monocyte-to-TAM differentiation in human monocytes THP-1. TNBC-derived conditional medium (CM) activated cell signaling pathways, including MAP kinase, AKT and STAT3, and increased the expression of TAM-related genes and proteins. These inductions were suppressed by HSP90 inhibition or by knockdown of HSP90 in TNBC. Additionally, we confirmed that TNBC secreted HSP90 extracellularly and that HSP90 itself promoted TAM differentiation. In a mouse tumor model, treatment with an HSP90 inhibitor suppressed tumor growth and reduced TAMs in the tumor microenvironment. Our findings demonstrate the role of HSP90 in TAM differentiation, suggesting HSP90 as a potential target for TNBC immunotherapy due to its regulatory role in monocyte-to-TAM differentiation.