Breast Cancer Immunotherapy Research Articles

Targeted editing of CCL5 with CRISPR-Cas9 nanoparticles enhances breast cancer immunotherapy.

Breast cancer remains one of the leading causes of cancer-related mortality among women worldwide. Immunotherapy, a promising therapeutic approach, often faces challenges due to the immunosuppressive tumor microenvironment. This study explores the innovative use of CRISPR-Cas9 technology in conjunction with FCPCV nanoparticles to target and edit the C-C Motif Chemokine Ligand 5 (CCL5) gene, aiming to improve the efficacy of breast cancer immunotherapy. Single-cell RNA sequencing (scRNA-seq) and TCGA-BRCA data identified CCL5 as a key immune-related gene in breast cancer. Using CRISPR-Cas9, sgRNA targeting CCL5 was designed and delivered to breast cancer cells and humanized mouse models via FCPCV nanoparticles. In vitro experiments demonstrated that FCPCV nanoparticles effectively silenced CCL5, enhanced CD8+ T cell activity, and increased the production of cytokines such as IFN-γ, TNF-α, and GZMB. In vivo studies revealed significant tumor suppression, improved immune microenvironment, and increased CD8+/CD4+ ratios in treated mice, without notable toxic side effects. These findings highlight the potential of CRISPR-Cas9 nanoparticle-mediated gene editing as a novel strategy for enhancing breast cancer immunotherapy, providing a new direction for personalized and effective cancer treatment.

Abstract P003: Harnessing macrophage plasticity and radiotherapy for breast cancer immunotherapy

Abstract Immunotherapies are a transformative force in clinical oncology, delivering prolonged disease-free survival in refractory cancers. However, in the setting of breast malignancies, clinical responses to immune checkpoint inhibitors (ICI) are both low and ephemeral, particularly in the hormone receptor-positive (HR+) subtype. Effective responses are predicated on abundant neoantigens, the activity of immune effector cells within the tumor microenvironment (TME), and the establishment of immunological memory. These prerequisites pose a significant efficacy barrier as BC patients carry low mutational burdens (neoantigens), and T-cells are profoundly hindered by the presence of immunosuppressive tumor-associated macrophages (TAMs). Radiotherapy (RT) holds a significant untapped potential to overcome the lack of neoantigens by triggering immunogenic cell death and recruiting adaptive immunity. However, the unavoidable tissue damage and clearance of dead cells by adjacent macrophages further enhance their wound-healing (immunosuppressive) phenotype, dampening the immunogenic potential of RT. Macrophages regulate immune responses through remarkably plastic activation states, including immune-stimulatory (M1) and immune-suppressive (M2). In breast tumors, macrophages undergo a well-documented but poorly understood “M2-education” process that facilitates immune evasion, utilizing a myriad of immune modulators (hormones, cytokines, and enzymes). Collectively, these dependencies highlight a tremendous therapeutic potential for combining RT with strategies that recover the M1 phenotype of TAMs, creating immune-supportive TME. Despite the potential, modulating TAM activities has proven exceptionally challenging, primarily due to the pleiotropic nature of their suppressive functions and the lack of scalable TME models to enable high-throughput target discovery. To overcome these limitations, we developed a scalable platform that recreates the breast TME at scale and phenotypic fidelity. This model contains the major BC constituents, including macrophages, tumor cells, and their supporting stroma, while preserving the functions, transcriptional programs, cell-cell interactions, and typical spatial organization. To identify reprogramming targets in TAMs, we performed a CRISPR screen utilizing Arg1 (a hallmark M2 marker) as a surrogate marker. Our screen exposed targets that convert immunosuppressive (M2) TAMs into immunostimulatory (M1) macrophages in established tumors. In vivo data show that TAM reprogramming is remarkably effective, promoting tumor regression and abscopal effect in HR+ and ovarian cancers. Reprogrammed TAMs enhanced responses to ICI and radiotherapy, a path we plan to optimize for future clinical development as “first-in-human” trials. Interventions that re-potentiate innate and adaptive immunities can benefit cancer patients, particularly those with limited therapeutic options. Our findings pioneer an actionable roadmap to unlock the full therapeutic potential of RT and immunotherapies in refractory human cancers. Citation Format: Jesus Sotelo, Xiang Niu, Rajasekhar K. Vinagolu, Maria S. Jiao, Sanjana E. Neville, Dan Avi Landau, Silvia C. Fermonti, Nir Ben Chetrit. Harnessing macrophage plasticity and radiotherapy for breast cancer immunotherapy. [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Translating Targeted Therapies in Combination with Radiotherapy; 2025 Jan 26-29; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2025;31(2_Suppl):Abstract nr P003

A Self-Amplifying Photodynamic Biomedicine for Cascade Immune Activation Against Triple-Negative Breast Cancer.

The efficacy of immunotherapy in triple-negative breast cancer (TNBC) is significantly hindered by its low immunogenicity and immunosuppressive tumor microenvironment. Non-invasive photodynamic therapy (PDT) is increasingly recognized as a potential immunotherapeutic stimulant in the treatment of TNBC. However, photodynamic immunotherapy is constrained by tumor hypoxia and excessive inflammation suppression during the course of treatment. Herein, a simple and efficacious biomedicine is formulated to overcome adverse influences by amplifying photodynamic immunotherapy, thereby stimulating the systemic immune response. Specifically, the approach targeted tumor delivery by employing specific agents such as the photosensitizer (verteporfin), the hypoxic ameliorator (atovaquone), and the cyclooxygenase-2/prostaglandin E2 (COX-2/PGE2) signaling blocker (celecoxib). More importantly, the biomedicine effectively ameliorated hypoxia and inhibited COX-2/PGE2 signaling, thereby amplifying PDT-induced immunogenic cell death. This, in turn, enhanced the efficacy of photodynamic immunotherapy and triggered a robust immune response cascade. Notably, the self-amplifying photodynamic biomedicine significantly inhibited primary tumors, distal tumors, lung metastases, and post-operative recurrence while maintaining high biocompatibility. To sum up, the work provides a viable cascade stimulation approach and an efficient biomedical nanoplatform, offering a novel strategy for photodynamic immunotherapy of TNBC in the clinic.

Extracellular matrix cancer-associated fibroblasts promote stromal fibrosis and immune exclusion in triple-negative breast cancer.

The impact of high heterogeneity of cancer-associated fibroblasts (CAFs) on triple-negative breast cancer (TNBC) immunotherapy response has not been fully elucidated, restricting progress in precision immuno-oncology. We integrated single-cell transcriptomic data from 18 TNBC patients and analyzed fibroblast subpopulations. Extracellular matrix CAFs (ecmCAFs) were identified as a fibroblast subpopulation with distinct ECM-associated characteristics. The ecmCAFs were significantly enriched in TNBC patients with residual disease after neoadjuvant immunotherapy and contributed to a fibrotic tumor microenvironment and T-cell exclusion. Secreted phosphoprotein 1 (SPP1) positive macrophages (SPP1+ Mφs) were closely localized to ecmCAFs and produced more transforming growth factor beta (TGFB1), interleukin 1 beta (IL1B), and SPP1 under hypoxic conditions. SPP1+ Mφs were found to facilitate the differentiation of normal breast fibroblasts to ecmCAFs, thus promoting ECM remodeling and stromal fibrosis. Our work revealed the critical role of ecmCAFs in generating a desmoplastic architecture and driving immunosuppression in TNBC. © 2025 The Pathological Society of Great Britain and Ireland.

Peptide-Drug Conjugate for Therapeutic Reprogramming of Tumor-Associated Macrophages in Breast Cancer.

In triple-negative breast cancer (TNBC), pro-tumoral macrophages promote metastasis and suppress the immune response. To target these cells, a previously identified CD206 (mannose receptor)-binding peptide, mUNO was engineered to enhance its affinity and proteolytic stability. The new rationally designed peptide, MACTIDE, includes a trypsin inhibitor loop, from the Sunflower Trypsin Inhibitor-I. Binding studies to recombinant CD206 revealed a 15-fold lower KD for MACTIDE compared to parental mUNO. Mass spectrometry further demonstrated a 5-fold increase in MACTIDE's half-life in tumor lysates compared to mUNO. Homing studies in TNBC-bearing mice shows that fluorescein (FAM)-MACTIDE precisely targeted CD206+ tumor-associated macrophages (TAM) upon intravenous, intraperitoneal, and even oral administration, with minimal liver accumulation. MACTIDE was conjugated to Verteporfin, an FDA-approved photosensitizer and YAP/TAZ pathway inhibitor to create the conjugate MACTIDE-V. In the orthotopic 4T1 TNBC mouse model, non-irradiated MACTIDE-V-treated mice exhibited anti-tumoral effects comparable to those treated with irradiated MACTIDE-V, with fewer signs of toxicity, prompting further investigation into the laser-independent activity of the conjugate. In vitro studies using bone marrow-derived mouse macrophages showed that MACTIDE-V excluded YAP from the nucleus, increased phagocytic activity, and upregulated several genes associated with cytotoxic anti-tumoral macrophages. In mouse models of TNBC, MACTIDE-V slowed primary tumor growth, suppressed lung metastases, and increased markers of phagocytosis and antigen presentation in TAM and monocytes, increasing the tumor infiltration of several lymphocyte subsets. MACTIDE-V is proposed as a promising peptide-drug conjugate for modulating macrophage function in breast cancer immunotherapy.

An on-Demand Oxygen Nano-vehicle Sensitizing Protein and Nucleic Acid Drug Augment Immunotherapy.

Hypoxia severely limits the antitumor immunotherapy for breast cancer. Although efforts to alleviate tumor hypoxia and drug delivery using diverse nanostructures achieve promising results, the creation of a versatile controllable oxygen-releasing nano-platform for co-delivery with immunostimulatory molecules remains a persistent challenge. To address this problem, a versatile oxygen controllable releasing vehicle PFOB@F127@PDA (PFPNPs) is developed, which effectively co-delivered either protein drug lactate oxidase (LOX) or nucleic acids drug unmethylated cytosine-phosphate-guanine oligonucleotide (CpG ODNs). Upon photothermal heating, this platform triggered oxygen release, thereby augmenting LOX-mediated lactate detection rates, and improving T cells infiltrating and cytokine expression. Moreover, under an oxygenated tumor microenvironment (TME), PFPNPs co-delivered with CpG ODNs effectively reprogrammed the immunosuppressive TME by repolarizing macrophages to an M1-like phenotype, promoting dendritic cells maturation, and increasing tumor-infiltrating T cells while decreasing the ratio of regulatory T cells (Tregs). Our study demonstrated that this controlled oxygen-releasing platform possessed adaptive drug-loading capabilities to meet varied immunotherapeutic demands in clinical settings.

Improved Efficacy of Triple-Negative Breast Cancer Immunotherapy via Hydrogel-Based Co-Delivery of CAR-T Cells and Mitophagy Agonist.

Leaky and structurally abnormal blood vessels and increased pressure in the tumor interstitium reduce the infiltration of CAR-T cells in solid tumors, including triple-negative breast cancer (TNBC). Furthermore, high burden of tumor cells may cause reduction of infiltrating CAR-T cells and their functional exhaustion. In this study, various effector-to-target (E:T) ratio experiments are established to model the treatment using CAR-T cells in leukemia (high E:T ratio) and solid tumor (low E:T ratio). It is found that the antitumor immune response is decreased in solid tumors with low E:T ratio. Furthermore, single cell sequencing is performed to investigate the functional exhaustion at a low ratio. It is revealed that the inhibition of mitophagy-mediated mitochondrial dysfunction diminished the antitumor efficacy of CAR-T-cell therapy. The mitophagy agonist BC1618 is screened via AI-deep learning and cytokine detection, in vivo and in vitro studies revealed that BC1618 significantly strengthened the antitumor response of CAR-T cells via improving mitophagy. Here, injection hydrogels are engineered for the controlled co-delivery of CAR-T cells and BC1618 that improves the treatment of TNBC. Local delivery of hydrogels creates an inflammatory and mitophagy-enhanced microenvironment at the tumor site, which stimulates the CAR-T cells proliferation, provides antitumor ability persistently, and improves the effect of treatment.

Harnessing the Potential of Metallic Nanoparticles for Modulating the Tumor Microenvironment and Immune Responses in Breast Cancer Immunotherapy

Utilizing the body's immune system to combat cancer has become a viable tactic known as cancer immunotherapy. Metallic nanoparticles, or MNPs, have drawn a lot of interest because of their special qualities and their uses in cancer immunotherapy. The manufacturing processes of MNPs, their function in altering the tumor microenvironment (TME), and their capacity to control immune cells for potent anticancer effects are all thoroughly covered in this review. The review underscores the benefits of MNPs in surmounting obstacles linked to traditional cancer treatments, including toxicity, resistance, and off-target effects. It also goes over the different ways that MNPs modulate the immune system, For example, by generating reactive oxygen species (ROS), reducing glutathione (GSH) levels, and improving hypoxia. The research also examines the ability of MNPs to enhance the maturation of dendritic cells, shift macrophages towards an M1 phenotype, stimulate T-cell responses, and aid in the transportation of natural killer (NK) cells. The investigation is focused on understanding the synergistic effects of MNPsIn conjunction with other immunotherapeutic approaches, such as checkpoint inhibitors and cell-based treatments, in order to generate potent immune responses against cancer.

Fe/Mo‐Based Lipid Peroxidation Nanoamplifier Combined with Adenosine Immunometabolism Regulation to Augment Anti‐Breast Cancer Immunity

AbstractImmunogenic cell death (ICD)‐mediated immunization strategies have great potential against breast cancer. However, traditional strategies neglect the increase in the immunosuppressive metabolite, adenosine (ADO), during ICD, leading to insufficient therapeutic outcomes. In this study, it is found that the adenosine A2A receptor (A2AR) is significantly expressed in breast cancer and positively associated with regulatory T (Treg) cells. Herein, a strategy combining Fe/Mo‐based lipid peroxidation (LPO) nanoamplifiers and A2AR blockade is reported to maximize ICD‐mediated anti‐tumor immunity. This LPO nanoamplifier causes LPO explosion by the Fe (II)‐mediated Fenton reaction and Mo(V)‐mediated Russell mechanism. Subsequently, it elicits the ICD magnification of tumor cells by inducing multiple regulated cell death patterns of ferroptosis, apoptosis, and necroptosis. Additionally, the A2AR antagonist (SCH58261), an immunometabolic checkpoint blocker, is found to relieve ADO‐related immunosuppression, amplify anti‐tumor immunological effects, and elicit immune memory responses. This robust anti‐tumor immunity is observed in primary, distant, pulmonary metastatic, and recurrent tumors. This study provides a novel strategy for optimizing ICD‐mediated immunotherapy and highlights the benefits of combining LPO explosion with A2AR blockade to enhance breast cancer immunotherapy.

Targeted Delivery of BMS-1166 for Enhanced Breast Cancer Immunotherapy.

Cancer immunotherapy has achieved great success in breast cancer treatment in recent years. The Programmed Death-1 (PD-1) /Programmed Death-Ligand 1 (PD-L1) immune checkpoint pathway is among the most studied. BMS-1166, a PD-L1 inhibitor, can interfere with PD-1 and PD-L1 interaction. Transferrin Receptor 1 is a transmembrane glycoprotein overexpressed in various cancer cells, including breast cancer, and can specifically interact with the T7 (HAIYPRH) peptide. This study hypothesized that BMS-1166-loaded T7-modified poly(ethylene glycol)-poly(ε-caprolactone) (PEG-PCL) polymeric micelles (BMS-T7) could block PD-L1 interaction with PD-1, serving as a targeted immunotherapy for TfR1-positive breast cancer. BMS-1166 was encapsulated in T7-PEG-PCL micelle. Particle size and zeta potential were determined by dynamic light scattering. Particle morphology was studied by transmission electron microscopy. The particles were characterized by Fourier transform infrared, thermogravimetric analysis, and differential scanning calorimetry. Drug encapsulation efficiency, loading degree, and release profile were examined by high-performance liquid chromatography. Human breast cancer MDA-MB-231 was used to test the cytotoxicity. Flow cytometry and immunofluorescence imaging were used to study the PD-L1 inhibition in cell surface and exosomes. MDA-MB-231 and Jurkat co-culture studied T-cell activation and apoptosis. The particle size of the empty and drug-loaded micelles showed a size distribution with an average diameter of 54.62 ± 2.28 nm and 60.22 ± 2.56 nm, respectively. The encapsulation efficiency of BMS-T7 was 83.89 ± 5.59%. The release half-life of drug-loaded micelles was 48h. The IC50 of BMS-1166 was 28.77μM in MDA-MB-231 cells. In addition, the BMS-T7 showed a better inhibitory effect on PD-L1 expression in breast cancer cells and exosomes than the naked drug. The formulation significantly restored T-cell function compared to the BMS-1166 treatment. These results provide preliminary evidence indicating that BMS-T7 may have the potential to deliver drugs to breast cancer cells via active targeting and hold great promise in cancer immunotherapy drug delivery applications.

A responsive cocktail nano-strategy breaking the immune excluded state enhances immunotherapy for triple negative breast cancer.

The exclusion of immune cells from the tumor can limit the effectiveness of immunotherapy in triple negative breast cancer (TNBC). The cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway plays a crucial role in priming adaptive anti-tumor immunity through the production of type I interferons (IFNs), facilitating the maturation of dendritic cells (DCs) and the function of T cells. Although the increased expression of programmed death-ligand 1 (PD-L1) upon STING activation is favorable for amplifying the efficacy of immune checkpoint inhibitors (ICIs) and realizing combination therapy, the penetration barrier remains a major obstacle. Herein, we fabricated a smart-responsive nanosystem (B&V@ZB-MCL) by integrating the extracellular matrix (ECM)-degrading drug losartan with a STING agonist (Vadimezan, abbreviated to Vad) and a PD-L1 inhibitor (BMS-1). Losartan was first released in the acidic tumor microenvironment to overcome the physical barrier, enhancing the penetration of immunotherapeutic components. Under the triggering of 1O2 generated by a photosensitizer (Ce6), the reactive oxygen species (ROS)-sensitive degradation of the nanocore ensured the site-directed release of Vad and BMS-1. The released Vad and damaged tumor DNA activated immune responses through the cGAS-STING pathway, while the elevated expression level of PD-L1 promoted the anti-tumor effect of BMS-1. Significant degradation of collagen fibers, restoration of immune effector cells, and lower tumor volume were observed in this integrated triple drug sequential therapy, which provides a promising prospect for TNBC treatment.

Promotion of triple negative breast cancer immunotherapy by combining bioactive radicals with immune checkpoint blockade.

Although immunotherapy has revolutionized clinical cancer treatment, the efficacy is limited due to the lack of tumor-associated antigens (TAAs) and the presence of compensatory immune checkpoints. To overcome the deficiency, a nano-system loaded with ozone and CD47 inhibitor RRx-001 is designed and synthesized. Upon irradiation, reactive oxygen species (ROS) generated from ozone reacts with nitric oxide (NO) metabolized from RRx-001 to form reactive nitrogen species (RNS), which presents a much stronger cell-killing ability than ROS. Molecular mechanism studies further reveal that RNS induce extensive immunogenic cell death (ICD). The released TAAs promote infiltration of cytotoxic T lymphocytes, which provides the basis for immune checkpoint blockade (ICB) therapy. Meanwhile, RRx-001 carried by the nanoparticles and the produced radicals repolarize M2-type tumor-associated macrophages (TAMs) into the anti-tumor M1-type, consequently reversing the immunosuppressive tumor microenvironment (TME). In a xenograft triple-negative breast cancer (TNBC) animal model, O3-001@lipo (liposome enwrapping O3 and RRx-001) plus irradiation shows a significant anti-tumor efficacy by improving cytotoxic lymphocyte infiltration and regulating immunosuppressive TME. In summary, the O3-001@lipo nano-system triggered by irradiation potently improves the efficacy of immunotherapy by introducing strong cytotoxic RNS, which not only enriches the toolbox of ICD inducer but also provides a strategy of treatment for immune deficient tumor. STATEMENT OF SIGNIFICANCE: This study introduces a nano-system that leverages ozone and RRx-001 in the presence of X-ray irradiation to generate reactive nitrogen species, enhancing immunogenic cell death and promoting T-lymphocyte infiltration in triple-negative breast cancer, addressing a significant unmet need in the field. The scientific contribution is the development of a clinically translatable nano-system that not only induces ICD but also reshapes the tumor microenvironment, which is expected to have a profound impact on the readership in pharmaceutics, material science, and nano-bio interaction, particularly for those interested in advanced immune therapy approaches.

Application of Gene Editing in Triple-Negative Breast Cancer Research.

With the rapid development of gene editing technology, its application in breast cancer has gradually become the focus of research. This article reviews the application of gene editing technology in the treatment of breast cancer, and discusses its challenges and future development directions. The key application areas of gene editing technology in the treatment of breast cancer will be outlined, including the discovery of new therapeutic targets and the development of drugs related to the pathway. Gene editing technology has played an important role in the discovery of new therapeutic targets. Through the use of gene editing technology, breast cancer-related genes are systematically edited to regulate key regulatory factors on related pathways or key tumor suppressor genes such as FOXC1 and BRCA, and the results are analyzed in cell or animal experiments, and the target is obtained from the experimental results, which provides important clues for the development of new drugs. This approach provides an innovative way to find more effective treatment strategies and inhibit tumor growth. In addition, gene editing technology has also promoted the personalization of breast cancer treatment. By analyzing a patient's genomic information, researchers can pinpoint key genetic mutations in a patient's tumor and design personalized treatments. This personalized treatment approach is expected to improve the therapeutic effect and reduce adverse reactions. Finally, the application of gene editing technology also provides support for the development of breast cancer immunotherapy. By editing immune cells to make them more potent against tumors, researchers are trying to develop more effective immunotherapies to bring new treatment options to breast cancer patients.

Predicting Triple-Negative Breast Cancer Immunotherapy Outcomes

Predicting Triple-Negative Breast Cancer Immunotherapy Outcomes

Identification of a novel immune checkpoint-related gene signature predicts prognosis and immunotherapy in breast cancer and experiment verification

Breast cancer (BRCA) is one of the pivotal causes of female death worldwide. And the morbidity and mortality of breast cancer have increased rapidly. Immune checkpoints are important to maintain immune tolerance and are regarded as important therapeutic targets. However, research for BRCA were limited to single immune checkpoint-related gene (ICG) and few studies have systematically explored expression profile of Immune checkpoint-related genes or attempted to construct a prognostic gene risk model based on immune checkpoint-related genes. We identified immune checkpoint-related differentially expressed genes (DEGs) in BRCA and normal breast tissues from TCGA database. A 7-gene signature was created by utilizing the univariate Cox regression model with least absolute shrinkage and selection operator (LASSO) Cox regression method. In addition, we conducted a nomogram to predict the prognostic significance. This tool enables quantitative prediction of patient prognosis, serving as a valuable reference for clinical decision-making, thereby improving patient outcomes. Relationships between our risk model and clinical indicators, TME (Tumor Microenvironment), immune cell infiltration, immune response and drug susceptibility were investigated. A set of in vitro cell assays was conducted to decipher the relationship between MAP2K6 and proliferation, invasion, migration, colony formation and apoptosis rate of breast cancer cells. As a result, we established a prognostic model composed of seven ICGs in BRCA. Based on the median risk score, BRCA patients were equally assigned into two groups of high- and low-risk. High-risk BRCA patients have poorer OS (overall survival) than low-risk patients. In addition, there were remarkable differences between these two groups in clinicopathological features, TME, immune cell infiltration, immune response and drug susceptibility. The results of GO and KEGG analyses indicated that DEGs between the high- and low-risk groups were involved in immune-related biological processes and pathways. GSEA analysis also showed that a number of immune-related pathways were notably enriched in the low-risk group. Finally, results of cell-based assays indicated that MAP2K6 may play a pivotal role in the initiation and progression of breast cancer as a tumor suppressor gene. In conclusion, we created a novel ICG signature that has the potential to predict the survival and drug sensitivity of BRCA patients. Furthermore, this study indicated that MAP2K6 may serve as a novel target for BRCA therapy.

Current and future immunotherapy for breast cancer.

Substantial therapeutic advancement has been made in the field of immunotherapy in breast cancer. The immune checkpoint inhibitor pembrolizumab in combination with chemotherapy received FDA approval for both PD-L1 positive metastatic and early-stage triple-negative breast cancer, while ongoing clinical trials seek to expand the current treatment landscape for immune checkpoint inhibitors in hormone receptor positive and HER2 positive breast cancer. Antibody drug conjugates are FDA approved for triple negative and HER2+ disease, and are being studied in combination with immune checkpoint inhibitors. Vaccines and bispecific antibodies are areas of active research. Studies of cellular therapies such as tumor infiltrating lymphocytes, chimeric antigen receptor-T cells and T cell receptor engineered cells are promising and ongoing. This review provides an update of recent major clinical trials of immunotherapy in breast cancer and discusses future directions in the treatment of breast cancer.

Ultrasound nanodroplets loaded with Siglec-G siRNA and Fe3O4 activate macrophages and enhance phagocytosis for immunotherapy of triple-negative breast cancer

BackgroundThe progression of triple-negative breast cancer is shaped by both tumor cells and the surrounding tumor microenvironment (TME). Within the TME, tumor-associated macrophages (TAMs) represent a significant cell population and have emerged as a primary target for cancer therapy. As antigen-presenting cells within the innate immune system, macrophages are pivotal in tumor immunotherapy through their phagocytic functions. Due to the highly dynamic and heterogeneous nature of TAMs, re-polarizing them to the anti-tumor M1 phenotype can amplify anti-tumor effects and help mitigate the immunosuppressive TME.ResultsIn this study, we designed and constructed an ultrasound-responsive targeted nanodrug delivery system to deliver Siglec-G siRNA and Fe3O4, with perfluorohexane (PFH) at the core and mannose modified on the surface (referred to as MPFS@NDs). Siglec-G siRNA blocks the CD24/Siglec-G mediated “don’t eat me” phagocytosis inhibition pathway, activating macrophages, enhancing their phagocytic function, and improving antigen presentation, subsequently triggering anti-tumor immune responses. Fe3O4 repolarizes M2-TAMs to the anti-tumor M1 phenotype. Together, these components synergistically alleviate the immunosuppressive TME, and promote T cell activation, proliferation, and recruitment to tumor tissues, effectively inhibiting the growth of primary tumors and lung metastasis.ConclusionThis work suggests that activating macrophages and enhancing phagocytosis to remodel the TME could be an effective strategy for macrophage-based triple-negative breast cancer immunotherapy.

From nature to clinic: Quercetin's role in breast cancer immunomodulation.

Immunotherapy has brought hope to many breast cancer patients, but not all patients benefit from it. Quercetin (Qu), a natural product found in various sources, has anti-inflammatory and anti-tumor properties. We conducted a review of the pharmacological research of Qu in regulating anti-tumor immunity in vivo and in vitro. Qu can directly regulate the local tumor microenvironment (TME) by enhancing the activity of immune cells which includes promoting the infiltration of T cells and natural killer (NK) cells, inhibiting the recruitment of myeloid-derived suppressor cells and tumor-associated macrophages. Additionally, Qu inhibits anaerobic glycolysis in tumor cells, thereby reducing the production and transport of lactic acid. It also suppresses tumor angiogenesis by targeting the vascular endothelial growth factor (VEGF) pathway and the vitamin D pathway. Furthermore, Qu can enhance the efficacy of immunotherapy for breast cancer by modulating the systemic microenvironment. This includes inhibiting obesity-related chronic inflammation to decrease the production of inflammatory factors, regulating the composition of intestinal microbiota, and intervening in the metabolism of intestinal flora. At the same time, we also address challenges in the clinical application of Qu, such as low absorption rates and unknown effective doses. In conclusion, we highlight Qu as a natural immunomodulator that enhances immune cell activity and has the potential to be developed as an adjunct for breast cancer.

Inhibiting intracellular CD28 in cancer cells enhances antitumor immunity and overcomes anti-PD-1 resistance via targeting PD-L1.

Deciphering mechanisms for cancer immune escape may provide targets for improving immunotherapy efficacy. By invivo genome-wide CRISPR loss-of-function screening in a mouse model of triple negative breast cancer (TNBC), we uncovered a non-classical function of Cd28 in cancer cells to promote immune escape. Knocking out Cd28 in cancer cells increased infiltration of type I conventional DC (cDC1) and activated tumor-specific CD8+ Tcells, and pharmaceutical inducible knockdown of Cd28 inhibited pre-established tumor growth and overcame anti-PD-1 resistance invivo. Furthermore, high expression of cancer cell CD28 in human TNBC tissues correlated with elevated PD-L1 expression, less CD8+ Tcell infiltration, and poor prognosis. Mechanistically, intracellular CD28 directly bound to Cd274 mRNA and recruited spliceosomal factor SNRPB2 to stabilize Cd274 mRNA in nucleus, promoting PD-L1 expression and immune escape. Therefore, disrupting cancer cell CD28-mediated immune escape may provide a potential approach to improve breast cancer immunotherapy.

A Novel Peroxisome-Related Gene Signature Predicts Breast Cancer Prognosis and Correlates with T Cell Suppression.

Peroxisomes are increasingly linked to cancer development, yet the prognostic role of peroxisome-related genes (PRGs) in breast cancer remains unclear. This study aimed to construct a prognostic model based on PRG expression in breast cancer to clarify their prognostic value and clinical implications. Transcriptomic data from TCGA and GEO were used for training and validation cohorts. TME characteristics were analyzed with ESTIMATE, MCP-counter, and CIBERSORT algorithms. qPCR validated mRNA expression levels of risk genes, and data analysis was conducted in R. Univariate and multivariate Cox regression identified a 7-gene PRG risk signature (ACBD5, ACSL5, DAO, NOS2, PEX3, PEX10, and SLC27A2) predicting breast cancer prognosis in training (n=1069), internal validation (n=327), and external validation (merged from four GEO datasets, n=640) datasets. While basal and Her2 subtypes had higher risk scores than luminal subtypes, a significant prognostic impact of the PRG risk signature was seen only in luminal subtypes. The high-risk subgroup exhibited a higher frequency of focal synonymous copy number alterations (SCNAs), arm-level amplifications and deletions, and single nucleotide variations. These increased genomic aberrations were associated with greater immune suppression and reduced CD8+ T cell infiltration. Bulk RNA sequencing and single-cell analyses revealed distinct expression patterns of peroxisome-related genes (PRGs) in the breast cancer TME: PEX3 was primarily expressed in malignant and stromal cells, while ACSL5 showed high expression in T cells. Additionally, the PRG risk signature demonstrated efficacy comparable to that of well-known biomarkers for predicting immunotherapy responses. Drug sensitivity analysis revealed that the PRG high-risk subgroup was sensitive to inhibitors of BCL-2 family proteins (BCL-2, BCL-XL, and MCL1) and other kinases (PLK1, PLK1, BTK, CHDK1, and EGFR). The PRG risk signature serves as a promising biomarker for evaluating peroxisomal activity, prognosis, and responsiveness to immunotherapy in breast cancer.