Breast Cancer Tumor Microenvironment Research Articles

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.

Interleukin signaling in the regulation of natural killer cells biology in breast cancer.

In the field of breast cancer treatment, the immunotherapy involving natural killer (NK) cells is increasingly highlighting its distinct potential and significance. Members of the interleukin (IL) family play pivotal regulatory roles in the growth, differentiation, survival, and apoptosis of NK cells, and are central to their anti-tumor activity. These cytokines enhance the ability of NK cells to recognize and eliminate tumor cells by binding to specific receptors and activating downstream signaling pathways. Furthermore, interleukins do not function in isolation; the synergistic or antagonistic interactions between different interleukins can drive NK cells toward various functional pathways, ultimately leading to diverse outcomes for breast cancer patients. This paper reviews the intricate relationship between NK cells and interleukins, particularly within the breast cancer tumor microenvironment. Additionally, we summarize the latest clinical studies and advancements in NK cell therapy for breast cancer, along with the potential applications of interleukin signaling in these therapies. In conclusion, this article underscores the critical role of NK cells and interleukin signaling in breast cancer treatment, providing valuable insights and a significant reference for future research and clinical practice.

The Role of Breastmilk in Macrophage-Tumour Cell Interactions in Postpartum Breast Cancer

Background: Lactation is associated with long-term reduced risk of breast cancer. However, there is a transient increased risk of breast cancer in the 5 to 10 years postpartum and this is associated with a high incidence of metastasis and mortality. Breastmilk is a physiological fluid secreted by the mammary glands intimately connected with breast cells and the microenvironment that may affect postpartum breast cancer development and progression. This study aims to investigate the effect of breastmilk on interactions between breast cancer cells and macrophages in vitro. Methods: Human breastmilk from healthy donors (n = 7) was pooled and incubated with breast cancer (MCF-7 and MDA-MB-231) and macrophage (RAW264.7) cell lines to assess cell proliferation, viability, migration, and expression of key genes associated with epithelial-mesenchymal transition (EMT) and macrophage phenotype. Indirect co-culture studies assessed the effect of breastmilk on interactions between breast cancer cells and macrophages. Results: Breastmilk increased the proliferation and viability of breast cancer cells, reduced EMT markers, and reduced cell migration in MDA-MB-231 cells. Breastmilk decreased mRNA expression of interleukin 1B (IL1B) and interleukin 10 (IL10) in macrophages. Reduced EMT marker expression was observed in breast cancer cells co-cultured with macrophages pre-treated with breastmilk. Macrophages co-cultured with breast cancer cells pre-treated with breastmilk exhibited increased expression of a pro-inflammatory cytokine tumor necrosis factor A (TNFA) and pro-inflammatory nitric oxide synthase 2 (NOS2), and reduced expression of cytokines IL10 and transforming growth factor B1 (TGFB1) which are associated with the alternatively-activated macrophage phenotype. Conclusions: Breastmilk has the potential to promote breast cancer proliferation, however, it can also reduce breast cancer progression through inhibition of breast cancer cell migration and regulation of macrophage polarisation. These findings suggest that breastmilk has potential to shape the tumour microenvironment in postpartum breast cancer.

α-Parvin Expression in Breast Cancer Tissues: Correlation with Clinical Parameters and Prognostic Significance.

Stromal cells play a critical role in the tumor microenvironment of breast cancer (BC), as they are recruited by tumor cells and regulate the metastatic spread. Though high expression of α-parvin, a member of the parvin family of actin-binding proteins, is reported to be associated with a poor prognosis and metastasis in several cancers, its role in carcinogenesis has not been thoroughly explored. Therefore, we aimed to examine the expression of α-parvin in BC patients by compartmentalizing and quantifying tissues to determine whether α-parvin can be a potential therapeutic target. We performed immunohistochemical (IHC) staining of α-parvin in BC tissues, and the IHC scores were calculated in the overall tissue, stroma, and epithelium using image analysis software. The expression of α-parvin was significantly higher in BC tissues (p = 0.0002) and BC stroma (p < 0.0001) than in normal tissues. Furthermore, all α-parvin scores were significantly positively correlated with the proliferation marker Ki67. The overall and stroma scores are associated with the tumor, (lymph) node, and metastasis (TNM) classification, stage, and grade. These results suggest that high expression of α-parvin in stroma is associated with BCs and might be a new predictive marker for diagnosing BC.

Single-cell RNA-sequencing reveals a unique landscape of the tumor microenvironment in obesity-associated breast cancer

Single-cell RNA-sequencing reveals a unique landscape of the tumor microenvironment in obesity-associated breast cancer

Unconventional p65/p52 NF-κB module regulates key tumor microenvironment-related genes in breast tumor-associated macrophages (TAMs)

The complex heterogeneity of tumor microenvironment (TME) of triple-negative breast cancer (TNBC) presents a significant obstacle to cytotoxic immune response and successful treatment, building up one of the most hostile oncological phenotypes. Among the most abundant TME components, tumor-associated macrophages (TAMs) have pivotal pro-tumoral functions, involving discordant roles for the nuclear factor kappa-B (NF-κB) transcription factors and directing to higher levels of pathway complexity.In both resting macrophages and TAMs, we recently revealed the existence of the uncharacterized NF-κB p65/p52 dimer. In the present study, we demonstrated its enhanced active nuclear localization in TAMs and validated selected immune target genes as directly regulated by dimer binding on DNA sequences.We demonstrated by ChIP-qPCR that p65/p52 enrichment on HSPG2 and CSF-1 regulatory regions is strictly dependent on macrophage polarization and tumor environment.Our data provide novel mechanisms of transcriptional regulation in TAMs, orchestrated by the varied and dynamic nature of NF-κB combinations, which needs to be considered when targeting this pathway in cancer therapies.Our results offer p65/p52, together with identified regulatory regions on genes impacting macrophage behavior and tumor biology, as novel molecular targets for TNBC, aimed at modulating TAMs functions towards anti-tumoral phenotypes and thus improving cancer treatment outcomes.

Characterizing the Tumor Microenvironment and Its Prognostic Impact in Breast Cancer.

The tumor microenvironment (TME) is crucial in cancer development and therapeutic response. Immunotherapy is increasingly recognized as a critical component of cancer treatment. While immunotherapies have shown efficacy in various cancers, including breast cancer, patient responses vary widely. Some patients receive significant benefits, while others experience minimal or no improvement. This disparity underscores the complexity and diversity of the immune system. In this study, we investigated the immune landscape and cell-cell communication within the TME of breast cancer through integrated analysis of bulk and single-cell RNA sequencing data. We established profiles of tumor immune infiltration that span across a broad spectrum of adaptive and innate immune cells. Our clustering analysis of immune infiltration identified three distinct patient groups: high T cell abundance, moderate infiltration, and low infiltration. Patients with low immune infiltration exhibited the poorest survival rates, while those in the moderate infiltration group showed better outcomes than those with high T cell abundance. Moreover, the high cell abundance group was associated with a greater tumor burden and higher rates of TP53 mutations, whereas the moderate infiltration group was characterized by a lower tumor burden and elevated PIK3CA mutations. Analysis of an independent single-cell RNA-seq breast cancer dataset confirmed the presence of similar infiltration patterns. Further investigation into ligand-receptor interactions within the TME unveiled significant variations in cell-cell communication patterns among these groups. Notably, we found that the signaling pathways SPP1 and EGF were exclusively active in the low immune infiltration group, suggesting their involvement in immune suppression. This work comprehensively characterizes the composition and dynamic interplay in the breast cancer TME. Our findings reveal associations between the extent of immune infiltration and clinical outcomes, providing valuable prognostic information for patient stratification. The unique mutations and signaling pathways associated with different patient groups offer insights into the mechanisms underlying diverse tumor immune infiltration and the formation of an immunosuppressive tumor microenvironment.

Decreased Expression of CD247 and CD4 Immune Marker Predicts Poor Prognosis in Triple Negative Breast Cancer.

Triple negative breast cancer (TNBC) is an aggressive from of breast cancer and is associated with poor prognosis. Tumor microenvironment of breast cancer consists of a wide range of cell types, including tumor-infiltrating lymphocytes (TILs). Accumulating evidence indicate that TILs play a crucial role in cancer progression and resistance to standard chemotherapy. We used online computational tools to evaluate the prognostic significance of CD247 and CD4 in TNBC. TNBC patients with lower expression of CD247 and CD4 have much shorter relapse- free survival and overall survival than the patients with higher expression of these genes. CD247 and CD4 expression show a strong positive correlation with tumor-infiltrating dendritic cells, B-cells, CD4+, CD8+, and neutrophils. We've concluded that low levels of CD247 and CD4 may stop immune cells from entering the area around the tumor, which stops cancer cells from being killed and gives the patient a bad outlook. These findings suggest that CD247 and CD4 may be useful biomarkers or as a target to understand the progression of TNBC. Our findings also suggest that CD247 and CD4 targeted therapeutics should be explored in detail, and could be a potentially used as atreatment strategy for TNBC.

Pan-Cancer Screening and Validation of CALU's Role in EMT Regulation and Tumor Microenvironment in Triple-Negative Breast Cancer.

Cancer-associated fibroblasts (CAFs) significantly contribute to tumor progression and the development of resistance to therapies across a range of malignancies, notably breast cancer. This study aims to elucidate the specific role and prognostic relevance of CALU across multiple cancer types. The association between CALU expression and prognosis, along with clinical characteristics in BRCA, HNSC, KIRP, LGG, and LIHC, was analyzed using data from the TCGA, GTEx, and GEO databases. Transcriptomic analysis of TCGA BRCA project data provided insights into the interaction between CALU and epithelial-mesenchymal transition (EMT) marker genes. Using TIMER and TISCH databases, the correlation between CALU expression and tumor microenvironment infiltration was assessed, alongside an evaluation of CALU expression across various cell types. Furthermore, CALU's influence on TNBC BRCA cell lines was explored, and its expression in tumor tissues was confirmed through immunohistochemical analysis of clinical samples. This study revealed a consistent upregulation of CALU across several tumor types, including BRCA, KIRP, LIHC, HNSC, and LGG, with elevated CALU expression being associated with unfavorable prognoses. CALU expression was particularly enhanced in clinical contexts linked to poor outcomes. Genomic analysis identified copy number alterations as the principal factor driving CALU overexpression. Additionally, a positive correlation between CALU expression and CAF infiltration was observed, along with its involvement in the EMT process in both CAFs and malignant cells. In vitro experiments demonstrated that CALU is highly expressed in TNBC-BRCA cell lines, and knockdown of CALU effectively reversed EMT progression and inhibited cellular migration. Immunohistochemical analysis of clinical samples corroborated the elevated expression of CALU in tumors, along with alterations in EMT markers. This comprehensive pan-cancer analysis underscores CALU's critical role in modulating the tumor microenvironment and facilitating cell migration via the EMT pathway, identifying it as a potential therapeutic target.

Paracrine Activation of STAT3 Drives GM-CSF Expression in Breast Carcinoma Cells, Generating a Symbiotic Signaling Network with Breast Carcinoma-Associated Fibroblasts.

This study evaluated the paracrine signaling between breast carcinoma-associated fibroblasts (CAFs) and breast cancer (BCa) cells. Resolving cell-cell communication in the BCa tumor microenvironment (TME) will aid the development of new therapeutics. Here, we utilized our patented TAME (tissue architecture and microenvironment engineering) 3D culture microphysiological system, which is a suitable pathomimetic avatar for the study of the BCa TME. We cultured in 3D BCa cells and CAFs either alone or together in cocultures and found that when cocultured, CAFs enhanced the invasive characteristics of tumor cells, as shown by increased proliferation and spread of tumor cells into the surrounding matrix. Secretome analysis from 3D cultures revealed a relatively high secretion of IL-6 by CAFs. A marked increase in the secretion of granulocyte macrophage-colony stimulating factor (GM-CSF) when carcinoma cells and CAFs were in coculture was also observed. We theorized that the CAF-secreted IL-6 functions in a paracrine manner to induce GM-CSF expression and secretion from carcinoma cells. This was confirmed by evaluating the activation of STAT3 and gene expression of GM-CSF in carcinoma cells exposed to CAF-conditioned media (CAF-CM). In addition, the treatment of CAFs with BCa cell-CM yielded a brief upregulation of GM-CSF followed by a marked decrease, indicating a tightly regulated control of GM-CSF in CAFs. Secretion of IL-6 from CAFs drives the activation of STAT3 in BCa cells, which in turn drives the expression and secretion of GM-CSF. As a result, CAFs exposed to BCa cell-secreted GM-CSF upregulate inflammation-associated genes such as IL-6, IL-6R and IL-8, thereby forming a positive feedback loop. We propose that the tight regulation of GM-CSF in CAFs may be a novel regulatory pathway to target for disrupting the CAF:BCa cell symbiotic relationship. These data provide yet another piece of the cell-cell communication network governing the BCa TME.