Dose-dependent bidirectional effects of gemcitabine in 4T1 breast tumors are associated with angiogenesis and PMN-MDSC-linked immunosuppression.

Nano-formulated chemotherapeutics prolong systemic availability of drugs and can reduce systemic toxicity, but their accumulation in solid tumours is often limited and unpredictable. Broadly applicable strategies to selectively enhance tumour delivery are lacking. We investigated whether subtherapeutic vascular disruption could be repurposed to transiently enhance tumour delivery of nano-formulated agents. Fluorescent reporter nanoparticles and the clinically approved nano-formulations Caelyx (doxorubicin) and Onivyde (irinotecan) were administered in combination with subtherapeutic doses of the vascular disrupting agent (VDA) combretastatin A4-phosphate (CA4P). Biodistribution, pharmacokinetics and therapeutic efficacy were assessed using longitudinal in vivo imaging and drug quantification via LC-MS/MS (liquid chromatography-tandem mass spectrometry) in syngeneic murine 4T1 breast cancer models. Co-administration of CA4P increased tumour accumulation of nano-formulated agents by up to threefold without increasing exposure in healthy organs. This effect was observed across reporter particles and both chemotherapeutic formulations but was not retained after repeated treatments. Consequently, CA4P co-treatment did not improve tumour growth inhibition under standard multi-dose therapeutic regimens. Low-dose vascular disruption can transiently and selectively enhance tumour delivery of nano-formulated agents but does not improve therapeutic efficacy with repeated dosing. This strategy may therefore be best suited to single-dose applications, such as diagnostic imaging or delivery studies, rather than sustained cancer therapy.

Obesity exacerbates breast cancer metastasis, yet the underlying mechanisms remain incompletely understood. Here, we identify neuregulin 4 (NRG4), a ligand of Erb-B2 receptor tyrosine kinase 4 (ERBB4), as a key regulator of metastasis, through the ERBB4-YAP1 signaling axis. Using MMTV-PyMT and 4T1 breast cancer models, we demonstrate that obesity accelerates metastasis, while NRG4, secreted by inguinal white adipose tissue (iWAT), inhibits cancer cell migration and epithelial-mesenchymal transition (EMT). Mechanistically, NRG4 activates ERBB4, producing a cleaved pERBB4 fragment that interacts with phosphorylated YAP1 (pYAP1), restricting its nuclear translocation. RNA sequencing revealed that NRG4 suppressed the transcription of Mmp9 and Mmp12, which encode matrix metalloproteinases critical for extracellular matrix remodeling and invasion. Co- immunoprecipitation and promoter assay confirmed that YAP1 bound to TEAD1 and activated MMP9/MMP12 transcription in the absence of NRG4. Importantly, recombinant NRG4 (rNRG4) reduced the growth and invasiveness of breast cancer organoids. These findings establish NRG4 as a metastasis suppressor in obesity-associated breast cancer by inhibiting the ERBB4-YAP1 pathway and down-regulating matrix metalloproteinases. Our study highlights the therapeutic potential of targeting NRG4-ERBB4 signaling to mitigate obesity-driven breast cancer progression.

Breast cancer immunotherapy is limited by the intrinsically low immunogenicity of tumors, which restricts T cell activation and reduces therapeutic efficacy. Pyroptosis, a proinflammatory form of programmed cell death (PCD), provides a strategy to overcome this limitation by releasing damage-associated molecular patterns (DAMPs) and cytokines that coactivate innate and adaptive immunity. An antimicrobial peptide (AMP)-based pyroptosis inducer (API) is developed to selectively disrupt mitochondrial homeostasis and trigger potent cytotoxic T cell responses. API consists of amphiphilic copolymers p(PPEm-co-AMPn), in which AMPs are clustered on nanoparticle surfaces to facilitate cellular uptake. Upon exposure to intracellular reactive oxygen species (ROS), phenylboronic pinacol ester (PPE) linkages are cleaved, leading to nanoparticle disassembly into linear polymers. This transition restores the membrane-lytic activity of AMPs, enabling selective mitochondrial disruption and efficient pyroptosis. Using the model peptide (KLAKLAK)2, API induces mitochondrial lysis and pyroptotic cell death, eliciting strong T cell activation. In a 4T1 breast cancer model, API treatment markedly suppresses tumor growth, metastasis, and recurrence without systemic toxicity. These results demonstrate API as a versatile nanoplatform for precise pyroptosis induction and highlight its promise for enhancing breast cancer immunotherapy.

Radiotherapy (RT) is inherently capable of eliciting antitumor immunity; yet, its systemic potential remains largely unexploited due to a critical disconnect between local immunogenic cell death and efficient immune priming. To bridge this gap, we designed a strategic nanoassembly of ginseng polysaccharides (GP) and chito-oligosaccharides (COS) to serve as a priming-booster that bridges local radiotherapy with systemic immune responses. This strategy leverages the intrinsic bioactivity of these polysaccharides to optimize surface charge, facilitating their targeted uptake by antigen-presenting cells (APCs). Our results demonstrate that the nanocomplex significantly boosts dendritic cells (DCs) maturation and antigen cross-presentation. Importantly, the assembly itself does not directly activate T cells, confirming that its therapeutic effect stems from the specific enhancement of DC-mediated antigen priming rather than nonspecific immune stimulation. In a murine 4T1 breast cancer model, this nanoassembly synergizes with RT to potently inhibit primary tumor growth and suppress pulmonary metastasis. Mechanistic studies reveal that the treatment orchestrates a profound "cold-to-hot" tumor transformation, characterized by the activation of DCs priming niches, increased CD8+ T cell infiltration, and multipronged M1-like macrophage repolarization. This work offers a sophisticated strategy to convert local radiotherapy into a systemic in situ vaccination hub, effectively amplifying the abscopal effect through refined immune priming.

Nanoparticle-based photothermal therapy (PTT) provides localized tumor ablation but remains limited by off-target accumulation and the need for high systemic doses. To address these challenges, we developed gold nanorods (AuNRs) coated with a multivalent glucose ligand (mvGlu-AuNR) that engages glucose transporter type 1 (GLUT1) for selective tumor delivery. This design leverages the Warburg effect, using GLUT1 as a metabolic Trojan horse to enter glycolytic cancer cells. In 4T1 breast cancer models, mvGlu-AuNR showed an 8-fold increase in gold content and a 3-fold rise in photoacoustic signal compared to nontargeted controls. Notably, mvGlu-AuNRs converted light to heat more efficiently than mPEG-AuNRs under identical irradiation conditions. ICP-MS analysis confirmed tumor-to-liver ratios ranging from 1.56 to 4.88, which is consistent with strong tumor localization and minimal hepatic uptake. At a systemic dose of 1 mg/kg, mvGlu-AuNRs enabled efficient tumor heating and slowed tumor growth without signs of off-target toxicity. These findings establish metabolic targeting as an effective strategy to enhance PTT specificity, reduce off-target exposure, and enable markedly lower gold dosing.

Stabilizing lysosome to facilitate verteporfin-based anticancer photodynamic therapy via trehalose co-assembled nanogel.

Photodynamic therapy (PDT) is a promising cancer treatment, yet its efficacy is often compromised by tumor hypoxia and limited immune activation. Here, we developed a multifunctional photosynthetic nanoplatform (PnanoCB) derived from Microcystis wesenbergii to alleviate hypoxia, enhance reactive oxygen species (ROS)-mediated tumor cell killing, and activate antitumor immunity. The cyanobacteria were restructured into protoplast-derived vesicles, retaining photosynthetic capacity and chlorophyll, and functionalized with a Matrix metalloproteinase-2 (MMP-2)-cleavable anti-PD-L1 peptide via a pH-sensitive pH low insertion peptide (pHLIP) linker for tumor-targeted immune checkpoint blockade. Upon red light irradiation, PnanoCB efficiently generated oxygen in situ, overcoming hypoxia and significantly amplifying PDT-induced ROS production. Combining PnanoCB with a fasting-mimicking diet (FMD) further improved tumor accumulation and therapeutic efficacy. The combination of PnanoCB, light irradiation, and FMD achieved the most potent tumor inhibition in a 4T1 breast cancer model and effectively prevented tumor recurrence in a rechallenge model, without detectable toxicity to major organs. Overall, PnanoCB significantly alleviates hypoxia, promotes immunogenic cell death, and triggers robust dendritic cell (DC) maturation through stimulator of interferon genes (STING) pathway activation. This study demonstrates a strategy integrating photosynthetic oxygen generation, photodynamic immunotherapy, and metabolic intervention to remodel the tumor microenvironment and elicit robust systemic antitumor immunity.

Engineering Escherichia coli Nissle 1917 to scavenge lactate enhances anti-tumor immunity.

Conventional cancer immunotherapy suffers from insufficient immune activation, immunosuppressive tumor microenvironment (TME), and rapid CpG adjuvant degradation. To address these challenges, we developed a G-quadruplex (G4)-modular CpG nanoplatform named IONP-G4-DOX/IMT, which uses iron oxide nanoparticles (IONPs) as a stable structural and biocompatible core and G4 as a multifunctional hub. The rationally designed G4 module enables three synergistic functions encompassing enhanced CpG nuclease resistance for sustained TLR9 pathway activation, site-specific loading of doxorubicin (DOX) to trigger potent immunogenic cell death (ICD) and release tumor antigens, and IMT anchoring to activate the cGAS-STING pathway. These three processes are structurally coordinated and functionally synergistic, collectively driving robust dendritic cell maturation, boosting CD4+/CD8+ T cell infiltration, and reducing regulatory T cell accumulation. This cascade of immune modulation effectively reprograms the TME into an immune-permissive state. In murine 4T1 breast cancer models, IONP-G4-DOX/IMT achieves a primary tumor suppression rate of approximately 79.4%, with no significant systemic toxicity. More importantly, it elicits potent long-term antitumor immunity that inhibits contralateral tumor growth, offering a versatile and promising strategy for advanced abscopal chemoimmunotherapy.

Phosphodiesterase 10A (PDE10A), a cyclic nucleotide-degrading enzyme, is overexpressed in various human cancers. While PDE10A inhibition using small-molecule inhibitors or gene silencing suppresses tumor growth in xenograft models, its precise mechanism of action and immunological impact remain unclear. Here, we report that ADT-030, a novel PDE10A inhibitor, exhibits potent cytotoxicity against a broad range of murine tumor cell lines. ADT-030 is orally bioavailable and effectively suppresses tumor growth across multiple syngeneic mouse models. Notably, its efficacy is diminished in immunodeficient mice or upon CD8 + T cell depletion, highlighting a critical dependence on host immunity. The immunostimulatory properties of ADT-030 are further supported by its ability to induce immunogenic tumor cell death and promote dendritic cell (DC) maturation, its reliance on Batf3-expressing DCs to elicit antitumor CD8 + T cell response, and its synergy with anti-PD-1 therapy. Comprehensive immune profiling in the 4T1 breast cancer model, both in orthotopic and metastatic settings, revealed that ADT-030 selectively reduces myeloid-derived suppressor cells (MDSCs) while normalizing the immune landscape within the tumor. Mechanistically, ADT-030 disrupts multiple components of the mitogen-activated protein kinase (MAPK) signaling network in both tumor cells and MDSCs, leading to induction of apoptosis in these populations. These findings highlight the multi-faceted impact of PDE10A inhibition as a therapeutic strategy that not only disrupts tumor-intrinsic oncogenic signaling to inhibit tumor progression but also reshapes the tumor immune microenvironment to unleash antitumor immunity.

Theranostic nanomedicine, combining therapy with diagnostic imaging, offers a powerful strategy for real-time monitoring and targeted treatment of cancer. In the current study, we developed a pH-sensitive delivery system based on chitosan (CS) and poly caprolactone-poly ethylene glycol- poly caprolactone (PCL-PEG-PCL) copolymer, which was conjugated to the AS1411 Aptamer and tagged with carbon dots (CDs), abbreviated as DOX/P/CS-CD-Apt. Then, the theranostic potential of DOX/P/CS-CD-Apt in carrying DOX to MCF-7 breast cancer cells was evaluated both in vitro and in vivo. CDs were synthesized via a one-step hydrothermal method and chemically conjugated to the CS backbone along with AS1411 using EDC/NHS chemistry. On the other hand, DOX is encapsulated into the final carrier through the double emulsion-solvent evaporation method. The nanocarrier was characterized using FT-IR, FESEM, XPS, XRD, TEM, DLS, and zeta potential. Our results represented that DOX/P/CS-CD-Apt were uniform spherical morphology, high drug encapsulation, and controlled release under acidic conditions. Fluorescence microscopy revealed cytoplasmic entrance of DOX/P/CS-CD-Apt in MCF-7 cells, indicating effective nucleolin-mediated uptake. MTT assays and apoptosis evaluation demonstrated the higher cytotoxicity and apoptotic effects compared to free DOX or non-targeted formulations. Moreover, in vivo PET imaging confirmed the selective accumulation of nanoparticles at the tumor site in a 4T1 breast cancer model, along with a notable reduction in tumor size. These findings highlight DOX/P/CS-CD-Apt as a promising theranostic platform for targeted breast cancer therapy with integrated imaging capability.

Dual-targeted fucoidan-TPP nanoparticles delivery system potently inhibit breast cancer via mitochondrial dysfunction and cGAS-STING activation.

Immunotherapy offers a promising paradigm for cancer treatment, but its efficacy is often constrained by tumor heterogeneity and the immunosuppressive tumor microenvironment. Herein, we constructed a multifunctional nanoplatform (termed MD1a NP) designed to elicit personalized antitumor immunity and overcome tumor immunosuppression by co-assembling a hypochlorous acid (HOCl)-responsive methylene blue (MB)–doxorubicin (DOX) dimer prodrug with a stimulator of interferon genes (STING) agonist (1a). Following intravenous administration, elevated intratumoral HOCl triggers the activation and release of MB and DOX, inducing nanoparticle disassembly and facilitating the liberation of 1a. Upon near-infrared laser irradiation, MB-mediated photodynamic therapy synergizes with DOX-induced chemotherapy to eradicate tumor cells and amplify immunogenic cell death, thereby enhancing the release of tumor antigens and damage-associated molecular patterns. This cascade promotes dendritic cell maturation, which is further reinforced by 1a-mediated STING activation. Moreover, MD1a NP treatment decreases regulatory T-cell populations, alleviates T-cell suppression, and promotes memory T-cell formation. Consequently, MD1a NP combined with laser irradiation remodels the immunosuppressive tumor microenvironment and effectively inhibits both primary and distant tumor growth while preventing lung metastasis in orthotopic 4T1 breast cancer models. This study provides insights into the design of tumor-activatable nanoplatforms for multimodal therapy against immune-desert cancers.

Tumor heterogeneity and immunosuppression limit the efficacy of conventional immunotherapy. Here, we introduce a spatiotemporally engineered nanoplatform (CAP/CyOH@NPs) that achieves multi-organelle targeting in tumor cells through POSS-based nanoconfinement. The rigid POSS cage co-encapsulates a photothermal agent (CyOH) and chemotherapeutic prodrug (capecitabine), enabling stable, simultaneous localization to lysosomes, mitochondria, and the endoplasmic reticulum-independent of pH or membrane potential. This subcellular precision enhances photothermal conversion (53.4%) and amplifies immunogenic cell death via coordinated organelle stress. When combined with PD-L1 blockade, the platform remodels the tumor immune microenvironment and suppresses both primary and distant tumors in a 4T1 breast cancer model. This work establishes a new paradigm for engineering nanomedicines with organelle-level specificity, offering a versatile strategy to overcome resistance in precision oncology.

A controllable self-amplifying oxidative stress strategy for boosting noninvasive sonodynamic therapy and synergistic immunotherapy.

Mesenchymal stem cells (MSCs) are recognized for their capacity to modulate immune responses, including those directed against tumors. In this study, we investigated the temporal effects of MSCs administration on anti-tumor immunity in a murine 4T1 breast cancer model. BALB/c mice were intraperitoneally injected with MSCs either 24 h (MSC1d) or 14 days (MSC14d) after orthotopic implantation of 4T1 mammary carcinoma cells. Early MSC administration (MSC1d) exhibited changes in immune cell phenotypes consistent with enhanced antitumor potential, including increased activity of natural killer (NK) cells, dendritic cells (DCs), macrophages, and T lymphocytes. These immunological changes correlated with reduced tumor growth and prolonged survival. Mice in the MSC1d group exhibited elevated serum levels of pro-inflammatory and anti-tumor cytokines (TNF-α, IFN-γ, IL-6, and IL-17), alongside decreased concentrations of immunosuppressive cytokines (TGF-β and IL-10). Tumor tissue analysis revealed increased infiltration of NK cells expressing markers associated with antitumor activity (IFN-γ-producing CD178⁺), CD80⁺/CD86⁺/I-A⁺ TNF-α-producing DCs, Th1-type CD4⁺ T cells, and Granzyme B-expressing CD8⁺ cytotoxic T lymphocytes (CTLs). Additionally, spleens of MSC1d-treated mice displayed significantly elevated populations of CD11c⁺ DCs, TNF-α/IFN-γ-secreting NK cells, CD4⁺ Th1 and Th17 cells, and CD8⁺ CTLs expressing markers associated with cytotoxic function (TNF-α, IFN-γ, and IL-17). Conversely, late MSCs administration (MSC14d) was associated with immunosuppression. Tumors from MSC14d-treated mice showed a decreased presence of IFN-γ⁺ and IL-17⁺ NK1.1⁺ cells, F4/80⁺ macrophages, IL-12⁺ DCs, and cytotoxic T cells. Spleens from these mice revealed a significant expansion of regulatory T cell (Treg)-like populations, including CD25⁻, FoxP3⁻, CD25⁺FoxP3⁻ cells, and TGF-β/IL-10-producing CD3⁺ and CD4⁺ T cells. Furthermore, serum levels of immunosuppressive mediators TGF-β and vascular endothelial growth factor (VEGF) were significantly elevated in the MSC14d group. Collectively, these findings demonstrate that the immunomodulatory effects of MSCs on breast cancer are highly dependent on the timing of their administration. Mesenchymal stem cells delivered during early tumor development enhance phenotypes consistent with antitumor potential and suppress tumor progression, whereas administration during later stages promotes immune evasion and tumor growth.

BackgroundTumor-associated macrophages (TAMs) are key drivers of the immunosuppressive tumor microenvironment (TME), thereby limiting the efficacy of immune checkpoint inhibitors (ICIs). However, the underlying mechanisms remain unclear.MethodsBoth genetic (Akr1b3 knockout) and pharmacologic (epalrestat) approaches were employed to examine the impact of Aldo-keto reductase family 1 member B1 (AKR1B1) inhibition on TAMs and T-cell function in vitro and in vivo. Mechanistic insights were obtained through RNA sequencing, flow cytometry, immunofluorescence staining, and co-culture assays. To assess therapeutic relevance, 4T1 breast cancer and LLC lung carcinoma mouse models were used to evaluate the effects of epalrestat on tumor growth, immune infiltration, and T-cell responses. Clinical relevance was validated in patient cohorts with triple-negative breast cancer (TNBC) and lung adenocarcinoma (LUAD).ResultsAKR1B1 is highly expressed in TAMs and correlates with CD8+ T-cell dysfunction. Targeting AKR1B1 enhances antitumor immunity by reprogramming TAMs. Mechanistically, AKR1B1 modulates macrophage metabolism via the glutathione/reactive oxygen species axis, suppressing nuclear factor κB activation and downregulating C-C motif chemokine ligand 5 (CCL5) production, thereby inducing CD8+ T-cell dysfunction and establishing an immunosuppressive TME. Inhibition of AKR1B1, either by gene knockout or selective pharmacologic blockade, reprograms TAMs toward an immunostimulatory phenotype, increases CCL5–CCR5 (C-C motif chemokine receptor 5) signaling, restores CD8+T cell effector function, and strengthens antitumor immunity. Clinically, high AKR1B1 expression is associated with poor prognosis and immune suppression in TNBC and LUAD. Notably, targeting AKR1B1 improves responses to ICIs in both breast and lung cancer models.ConclusionsAKR1B1 as a critical regulator of TAM-mediated immunosuppression and highlight its therapeutic potential to enhance the efficacy of ICIs.

To circumvent the lingering limitations of photodynamic therapy, we developed a novel naphthalene-derived endoperoxide through structural optimization of 1,4-dimethylnaphthalene. Strategic introduction of an amide group at the 2-position enabled precise modulation of steric and electronic properties, resulting in prolonged 1O2 release half-life (t1/2 = 8.6 h) compared to simpler derivatives. This temporal control is likely to result in more 1O2 release in tumor tissues, significantly enhancing the therapeutic effect. Our studies reveal that thermal cycloreversion drives 1O2 generation from these compounds, achieving potent cytotoxicity in cancer cell cultures (IC50 = 11.6 µM). In vivo evaluation using a murine 4T1 breast cancer model demonstrated marked tumor suppression following intraperitoneal administration, with no observable systemic toxicity at the therapeutic doses. To enable real-time evaluation of therapeutic efficacy, we designed a modular system combining a naphthalimide fluorescent group with an H2O2-responsive phenylboronic ester. This construct capitalizes on the pathological overproduction of H2O2, a well-established biomarker of tumor progression. When exposed to elevated H2O2 levels in cancer cells, the phenylboronic ester undergoes specific cleavage to generate hydroxyl groups. This structural transformation triggers a blue-to-green fluorescence emission change, providing direct visual confirmation of therapeutic activation within the tumor microenvironment.

Chaihu Longgu Muli Decoction attenuates chronic stress-induced endothelial dysfunction and potentiates chemotherapy in breast cancer by inhibiting cAMP/PKA/CREB1 mediated glycolysis.