Mouse 4T1 breast tumor model

The F-actin bundler SWAP-70 promotes tumor metastasis

Dynamic rearrangements of the F-actin cytoskeleton are a hallmark of tumor metastasis. Thus, proteins that govern F-actin rearrangements are of major interest for understanding metastasis and potential therapies. We hypothesized that the unique F-actin binding and bundling protein SWAP-70 contributes importantly to metastasis. Orthotopic, ectopic, and short-term tail vein injection mouse breast and lung cancer models revealed a strong positive dependence of lung and bone metastasis on SWAP-70. Breast cancer cell growth, migration, adhesion, and invasion assays revealed SWAP-70's key role in these metastasis-related cell features and the requirement for SWAP-70 to bind F-actin. Biophysical experiments showed that tumor cell stiffness and deformability are negatively modulated by SWAP-70. Together, we present a hitherto undescribed, unique F-actin modulator as an important contributor to tumor metastasis.

Discovery of Orally Bioavailable and Potent CDK9 Inhibitors for Targeting Transcription Regulation in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) represents a highly aggressive and heterogeneous malignancy. Currently, effective therapies for TNBC are very limited and remain a significant unmet clinical need. Targeting the transcription-regulating cyclin-dependent kinase 9 (CDK9) has emerged as a promising avenue for therapeutic treatment of TNBC. Herein, we report the design, synthesis, optimization, and evaluation of a new series of aminopyrazolotriazine compounds as orally bioavailable, potent, and CDK9/2 selectivity-improved inhibitors, enabling efficacious inhibition of TNBC cell growth, as well as notable antitumor effect in TNBC models. The compound C35 demonstrated low-nanomolar potency with substantially improved CDK9/2 selectivity, downregulated the CDK9-downstream targets (e.g., MCL-1), and induced apoptosis in TNBC cell lines. Moreover, with the desired oral bioavailability, oral administration of C35 could significantly suppress the tumor progression in two TNBC mouse models. This study demonstrates that target transcriptional regulation is an effective strategy and holds promising potential as a targeted therapy for the treatment of TNBC.

Triclocarban and triclosan promote breast cancer progression in vitro and in vivo via activating G protein-coupled estrogen receptor signaling pathways

Triclocarban (TCC) and triclosan (TCS) have been detected ubiquitously in human body and evoked increasing concerns. This study aimed to reveal the induction risks of TCC and TCS on triple negative breast cancer through non-genomic GPER-mediated signaling pathways. Molecular simulation indicated that TCC exhibited higher GPER binding affinity than TCS theoretically. Calcium mobilization assay displayed that TCC/TCS activated GPER signaling pathway with the lowest observed effective concentrations (LOEC) of 10 nM/100 nM. TCC and TCS also upregulated MMP-2/9, EGFR, MAPK3 but downregulated MAPK8 via GPER-mediated signaling pathway. Proliferation assay showed that TCC/TCS induced 4 T1 breast cancer cells proliferation with the LOEC of 100 nM/1000 nM. Wound-healing and transwell assays showed that TCC/TCS promoted 4 T1 cells migration in a concentration-dependent manner with the LOEC of 10 nM. The effects of TCC on breast cancer cells proliferation and migration were stronger than TCS and both were regulated by GPER. TCC/TCS induced migratory effects were more significantly than proliferative effect. Mechanism study showed that TCC/TCS downregulated the expression of epithelial marker (E-cadherin) but upregulated mesenchymal markers (snail and N-cadherin), which was reversed by GPER inhibitor G15. These biomarkers results indicated that TCC/TCS-induced 4 T1 cells migration was a classic epithelial to mesenchymal transition mechanism regulated by GPER signaling pathway. Orthotopic tumor model verified that TCC promoted breast cancer in-situ tumor growth and distal tissue metastasis via GPER-mediated signaling pathway at human-exposure level of 10 mg/kg/d. TCC-induced tissue metastasis of breast cancer was more significantly than in-situ tumor growth. Overall, we demonstrated for the first time that TCC/TCS could activate the GPER signaling pathways to induce breast cancer progression.

Bioelectrocatalytic Activity of One-Dimensional Porous Pt Nanoribbons for Efficient Inhibition of Tumor Growth and Metastasis

Designing and synthesizing one-dimensional porous Pt nanocrystals with unique optical, electrocatalytic, and theranostic properties are gaining lots of attention, especially to overcome the challenges of tumor recurrence and resistance to platinum-based chemotherapy. Herein, we represented an interesting report of a one-step and facile strategy for synthesizing multifunctional one-dimensional (1D) porous Pt nanoribbons (PtNRBs) with highly efficient therapeutic effects on cancer cells based on inherent electrocatalytic activity. The critical point in the formation of luminescent porous PtNRBs was the use of human hemoglobin (Hb) as a shape-regulating, stabilizing, and reducing agent with facet-specific domains on which fluorescent platinum nanoclusters at first are aggregated by aggregation-induced emission phenomena (AIE) and then crystallized into contact and penetration twins, as intermediate products, followed by shaping of the final luminescent porous ribbon nanomaterials, owing to oriented attachment association via the Ostwald ripening mechanism. From a medical point of view, the key strategy for effective cancer therapy occured via using low-dosage ethanol in the presence of electroactive porous PtNRBs based on intracellular ethanol oxidation-mediated reactive oxygen species (ROS) generation. The role of heme groups of Hb, as electrocatalytically active centers, was successfully demonstrated in both kinetically controlled anisotropic growth of NRBs for slowing down the reduction of Pt(II) followed by oligomerization of Pt(II)-Hb complexes via platinophilic interactions as well as electrocatalytic ethanol oxidation for therapy. Interestingly, hyaluronic acid-targeted (HA) Hb-PtNRB in the presence of low-dose ethanol caused extraordinary arrest of tumor growth and metastasis with no recurrence even after the treatment course stopped, which caused elongation of tumor-bearing mice survival. HA/Hb-PtNRB was completely biocompatible and exhibited high tumor-targeting efficacy for fluorescent imaging of breast tumors. Therefore, the synergistic electrocatalytic activity of PtNRBs is presented as an efficient and safe cancer theranostic method for the first time.

Nanoassemblies designed for efficient nuclear targeting

One of the key aspects of coping efficiently with complex pathological conditions is delivering the desired therapeutic compounds with precision in both space and time. Therefore, the focus on nuclear-targeted delivery systems has emerged as a promising strategy with high potential, particularly in gene therapy and cancer treatment. Here, we explore the design of supramolecular nanoassemblies as vehicles to deliver specific compounds to the nucleus, with the special focus on polymer and peptide-based carriers that expose nuclear localization signals. Such nanoassemblies aim at maximizing the concentration of genetic and therapeutic agents within the nucleus, thereby optimizing treatment outcomes while minimizing off-target effects. A complex scenario of conditions, including cellular uptake, endosomal escape, and nuclear translocation, requires fine tuning of the nanocarriers' properties. First, we introduce the principles of nuclear import and the role of nuclear pore complexes that reveal strategies for targeting nanosystems to the nucleus. Then, we provide an overview of cargoes that rely on nuclear localization for optimal activity as their integrity and accumulation are crucial parameters to consider when designing a suitable delivery system. Considering that they are in their early stages of research, we present various cargo-loaded peptide- and polymer nanoassemblies that promote nuclear targeting, emphasizing their potential to enhance therapeutic response. Finally, we briefly discuss further advancements for more precise and effective nuclear delivery.

ROS mediated Cu[Fe(CN)5NO] nanoparticles for triple negative breast cancer: A detailed study in preclinical mouse model

Triple negative breast cancer (TNBC) is an aggressive form of tumor, more prevalent in younger women resulting in poor survival rate (2nd in cancer deaths) because of its asymptomatic existence. The most popular and convenient approach for the treatment of TNBC is chemotherapy which is associated with several limitations. Considering the importance of nanotechnology in health care system, in the present manuscript, we have designed and developed a simple, efficient, cost effective, and ecofriendly method for the synthesis of copper nitroprusside analogue nanoparticles (Cu[Fe(CN)5NO] which is abbreviated as CuNPANP that may be the potential anti-cancer nanomedicine for the treatment of TNBC. Copper (present in CuNPANP) is used because of its affordability, nutritional value and various biomedical applications. The CuNPANP are thoroughly characterized using several analytical techniques. The in vitro cell viability (in normal cells) and the ex vivo hemolysis assay reveal the biocompatible nature of CuNPANP. The anti-cancer activity of the CuNPANP is established in TNBC cells (MDA-MB-231 and 4T1) through several in vitro assays along with plausible mechanisms. The intraperitoneal administration of CuNPANP in orthotopic breast tumor model by transplanting 4T1 cells into the mammary fat pad of BALB/c mouse significantly inhibits the growth of breast carcinoma as well as increases the survival time of tumor-bearing mice. These results altogether potentiate the anti-cancer efficacy of CuNPANP as a smart therapeutic nanomedicine for treating TNBC in near future after bio-safety evaluation in large animals.

Nanoparticles Synergize Ferroptosis and Cuproptosis to Potentiate Cancer Immunotherapy

The recent discovery of copper-mediated and mitochondrion-dependent cuproptosis has aroused strong interest in harnessing this novel mechanism of cell death for cancer therapy. Here the design of a core-shell nanoparticle, CuP/Er, for the co-delivery of copper (Cu) and erastin (Er) to cancer cells for synergistic cuproptosis and ferroptosis is reported. The anti-Warburg effect of Er sensitizes tumor cells to Cu-mediated cuproptosis, leading to irreparable mitochondrial damage by depleting glutathione and enhancing lipid peroxidation. CuP/Er induces strong immunogenic cell death, enhances antigen presentation, and upregulates programmed death-ligand 1 expression. Consequently, CuP/Er promotes proliferation and infiltration of T cells, and when combined with immune checkpoint blockade, effectively reinvigorates T cells to mediate the regression of murine colon adenocarcinoma and triple-negative breast cancer and prevent tumor metastasis. This study suggests a unique opportunity to synergize cuproptosis and ferroptosis with combination therapy nanoparticles to elicit strong antitumor effects and potentiate current cancer immunotherapies.

Adjuvant COX inhibition augments STING signaling and cytolytic T cell infiltration in irradiated 4T1 tumors

Immune therapy is the new frontier of cancer treatment. Therapeutic radiation is a known inducer of immune response and can be limited by immunosuppressive mediators including cyclooxygenase-2 (COX2) that is highly expressed in aggressive triple negative breast cancer (TNBC). A clinical cohort of TNBC tumors revealed poor radiation therapeutic efficacy in tumors expressing high COX2. Herein, we show that radiation combined with adjuvant NSAID (indomethacin) treatment provides a powerful combination to reduce both primary tumor growth and lung metastasis in aggressive 4T1 TNBC tumors, which occurs in part through increased antitumor immune response. Spatial immunological changes including augmented lymphoid infiltration into the tumor epithelium and locally increased cGAS/STING1 and type I IFN gene expression were observed in radiation-indomethacin-treated 4T1 tumors. Thus, radiation and adjuvant NSAID treatment shifts "immune desert phenotypes" toward antitumor M1/TH1 immune mediators in these immunologically challenging tumors. Importantly, radiation-indomethacin combination treatment improved local control of the primary lesion, reduced metastatic burden, and increased median survival when compared with radiation treatment alone. These results show that clinically available NSAIDs can improve radiation therapeutic efficacy through increased antitumor immune response and augmented local generation of cGAS/STING1 and type I IFNs.

Prostate Specific Membrane Antigen Expression in a Syngeneic Breast Cancer Mouse Model

PURPOSE

Prostate specific membrane antigen (PSMA) has been studied in human breast cancer (BCa) biopsies, however, lack of data on PSMA expression in mouse models impedes development of PSMA-targeted therapies, particularly in improving breast conserving surgery (BCS) margins. This study aimed to validate and characterize the expression of PSMA in murine BCa models, demonstrating that PSMA can be utilized to improve therapies and imaging techniques.

METHODS

Murine triple negative breast cancer 4T1 cells, and human cell lines, MDA-MB-231, MDA-MB-468, implanted into the mammary fat pads of BALB/c mice, were imaged by our PSMA targeted theranostic agent, PSMA-1-Pc413, and tumor to background ratios (TBR) were calculated to validate selective uptake. Immunohistochemistry was used to correlate PSMA expression in relation to CD31, an endothelial cell biomarker highlighting neovasculature. PSMA expression was also quantified by Reverse Transcriptase Polymerase Chain Reaction (RT-PCR).

RESULTS

Accumulation of PSMA-1-Pc413 was observed in 4T1 primary tumors and associated metastases. Average TBR of 4T1 tumors were calculated to be greater than 1.5-ratio at which tumor tissues can be distinguished from normal structures-at peak accumulation with the signal intensity in 4T1 tumors comparable to that in high PSMA expressing PC3-pip tumors. Extraction of 4T1 tumors and lung metastases followed by RT-PCR analysis and PSMA-CD31 co-staining shows that PSMA is consistently localized on tumor neovasculature with no expression in tumor cells and surrounding normal tissues.

CONCLUSION

The selective uptake of PSMA-1-Pc413 in these cancer tissues as well as the characterization and validation of PSMA expression on neovasculature in this syngeneic 4T1 model emphasizes their potential for advancements in targeted therapies and imaging techniques for BCa. PSMA holds great promise as an oncogenic target for BCa and its associated metastases.

Fusogenic vesicular stomatitis virus combined with natural killer T cell immunotherapy controls metastatic breast cancer

BACKGROUND

Metastatic breast cancer is a leading cause of cancer death in woman. Current treatment options are often associated with adverse side effects and poor outcomes, demonstrating the need for effective new treatments. Immunotherapies can provide durable outcomes in many cancers; however, limited success has been achieved in metastatic triple negative breast cancer. We tested whether combining different immunotherapies can target metastatic triple negative breast cancer in pre-clinical models.

METHODS

Using primary and metastatic 4T1 triple negative mammary carcinoma models, we examined the therapeutic effects of oncolytic vesicular stomatitis virus (VSVΔM51) engineered to express reovirus-derived fusion associated small transmembrane proteins p14 (VSV-p14) or p15 (VSV-p15). These viruses were delivered alone or in combination with natural killer T (NKT) cell activation therapy mediated by adoptive transfer of α-galactosylceramide-loaded dendritic cells.

RESULTS

Treatment of primary 4T1 tumors with VSV-p14 or VSV-p15 alone increased immunogenic tumor cell death, attenuated tumor growth, and enhanced immune cell infiltration and activation compared to control oncolytic virus (VSV-GFP) treatments and untreated mice. When combined with NKT cell activation therapy, oncolytic VSV-p14 and VSV-p15 reduced metastatic lung burden to undetectable levels in all mice and generated immune memory as evidenced by enhanced in vitro recall responses (tumor killing and cytokine production) and impaired tumor growth upon rechallenge.

CONCLUSION

Combining NKT cell immunotherapy with enhanced oncolytic virotherapy increased anti-tumor immune targeting of lung metastasis and presents a promising treatment strategy for metastatic breast cancer.

Coiled-Coil Protein Hydrogels Engineered with Minimized Fiber Diameters for Sustained Release of Doxorubicin in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) lacks expressed protein targets, making therapy development challenging. Hydrogels offer a promising new route in this regard by improving the chemotherapeutic efficacy through increased solubility and sustained release. Moreover, subcutaneous hydrogel administration reduces patient burden by requiring less therapy and shorter treatment times. We recently established the design principles for the supramolecular assembly of single-domain coiled-coils into hydrogels. Using a modified computational design algorithm, we designed Q8, a hydrogel with rapid assembly for faster therapeutic hydrogel preparation. Q8 encapsulates and releases doxorubicin (Dox), enabling localized sustained release via subcutaneous injection. Remarkably, a single subcutaneous injection of Dox-laden Q8 (Q8•Dox) significantly suppresses tumors within just 1 week. This work showcases the bottom-up engineering of a fully protein-based drug delivery vehicle for improved TBNC treatment via noninvasive localized therapy.

Preclinical Evaluation of virus-like particle Vaccine Against Carbonic Anhydrase IX Efficacy in a Mouse Breast Cancer Model System

Carbonic anhydrase IX (CAIX) is a cancer-associated membrane protein frequently overexpressed in hypoxic solid tumours leading to enhanced tumour cell survival and invasion, and it has been proposed to be an attractive tumour-specific molecule for antibody-mediated targeting. This study aimed to generate a virus-like particle (VLP)-based CAIX vaccine candidate and evaluate its efficacy in a mouse model of breast cancer. The prototype murine vaccine was developed based on the ssRNA bacteriophage Qbeta VLPs with chemically coupled murine CAIX protein catalytic domains on their surfaces. The vaccine was shown to efficiently break the natural B cell tolerance against autologous murine CAIX and to induce high-titre Th1-oriented IgG responses in the BALB/c mice. This vaccine was tested in a therapeutic setting by using a triple-negative breast cancer mouse model system comprising 4T1, 4T1-Car9KI and 4T1-Car9KO cells, the latter representing positive and negative controls for murine CAIX production, respectively. The humoural immune responses induced in tumour-bearing animals were predominantly of Th1-type and higher anti-mCAIXc titres correlated with slower growth and lung metastasis development of 4T1 tumours constitutively expressing mCAIX in vivo in the syngeneic host.

Targeting PD-L1 in solid cancer with myeloid cells expressing a CAR-like immune receptor

Introduction

Solid cancers Myeloid cells are prevalent in solid cancers, but they frequently exhibit an anti-inflammatory pro-tumor phenotype that contribute to the immunosuppressive tumor microenvironment (TME), which hinders the effectiveness of cancer immunotherapies. Myeloid cells' natural ability of tumor trafficking makes engineered myeloid cell therapy an intriguing approach to tackle the challenges posed by solid cancers, including tumor infiltration, tumor cell heterogenicity and the immunosuppressive TME. One such engineering approach is to target the checkpoint molecule PD-L1, which is often upregulated by solid cancers to evade immune responses.

Method

Here we devised an adoptive cell therapy strategy based on myeloid cells expressing a Chimeric Antigen Receptor (CAR)-like immune receptor (CARIR). The extracellular domain of CARIR is derived from the natural inhibitory receptor PD-1, while the intracellular domain(s) are derived from CD40 and/or CD3ζ. To assess the efficacy of CARIR-engineered myeloid cells, we conducted proof-of-principle experiments using co-culture and flow cytometry-based phagocytosis assays in vitro. Additionally, we employed a fully immune-competent syngeneic tumor mouse model to evaluate the strategy's effectiveness in vivo.

Result

Co-culturing CARIR-expressing human monocytic THP-1 cells with PD-L1 expressing target cells lead to upregulation of the costimulatory molecule CD86 along with expression of proinflammatory cytokines TNF-1α and IL-1β. Moreover, CARIR expression significantly enhanced phagocytosis of multiple PD-L1 expressing cancer cell lines in vitro. Similar outcomes were observed with CARIR-expressing human primary macrophages. In experiments conducted in syngeneic BALB/c mice bearing 4T1 mammary tumors, infusing murine myeloid cells that express a murine version of CARIR significantly slowed tumor growth and prolonged survival.

Conclusion

Taken together, these results demonstrate that adoptive transfer of PD-1 CARIR-engineered myeloid cells represents a promising strategy for treating PD-L1 positive solid cancers.

ΔNp63 regulates MDSC survival and metabolism in triple-negative breast cancer

Triple-negative breast cancer (TNBC) contributes greatly to mortality of breast cancer, demanding new targetable options. We have shown that TNBC patients have high ΔNp63 expression in tumors. However, the function of ΔNp63 in established TNBC is yet to be explored. In current studies, targeting ΔNp63 with inducible CRISPR knockout and Histone deacetylase inhibitor Quisinostat showed that ΔNp63 is important for tumor progression and metastasis in established tumors by promoting myeloid-derived suppressor cell (MDSC) survival through tumor necrosis factor alpha. Decreasing ΔNp63 levels are associated with decreased CD4+ and FOXP3+ T-cells but increased CD8+ T-cells. RNA sequencing analysis indicates that loss of ΔNp63 alters multiple MDSC properties such as lipid metabolism, chemotaxis, migration, and neutrophil degranulation besides survival. We further demonstrated that targeting ΔNp63 sensitizes chemotherapy. Overall, we showed that ΔNp63 reprograms the MDSC-mediated immunosuppressive functions in TNBC, highlighting the benefit of targeting ΔNp63 in chemotherapy-resistant TNBC.

Geraniol and citral: recent developments in their anticancer credentials opening new vistas in complementary cancer therapy

About 10 million people are diagnosed with cancer each year. Globally, it is the second leading cause of death after heart disease, and by 2035, the death toll could reach 14.6 million. Several drugs and treatments are available to treat cancer, but survival rates remain low. Many studies in recent years have shown that plant-derived monoterpenes, particularly geraniol and citral, are effective against various cancers, including breast, liver, melanoma, endometrial, colon, prostate, and skin cancers. This trend has opened new possibilities for the development of new therapeutics or adjuvants in the field of cancer therapy. These monoterpenes can improve the efficacy of chemotherapy by modulating many signaling molecules and pathways within tumors. Analysis of reports on the anticancer effects published in the past 5 years provided an overview of the most important results of these and related properties. Also, the molecular mechanisms by which they exert their anticancer effects in cell and animal studies have been explained. Therefore, this review aims to highlight the scope of geraniol and citral as complementary or alternative treatment options in cancer therapy.

Co-delivery of fucoxanthin and Twist siRNA using hydroxyethyl starch-cholesterol self-assembled polymer nanoparticles for triple-negative breast cancer synergistic therapy

INTRODUCTION

Triple-negative breast cancer (TNBC) represents the most aggressive subtype of breast cancer with an extremely dismal prognosis and few treatment options. As a desmoplastic tumor, TNBC tumor cells are girdled by stroma composed of cancer-associated fibroblasts (CAFs) and their secreted stromal components. The rapidly proliferating tumor cells, together with the tumor stroma, exert additional solid tissue pressure on tumor vasculature and surrounding tissues, severely obstructing therapeutic agent from deep intratumoral penetration, and resulting in tumor metastasis and treatment resistance.

OBJECTIVES

Fucoxanthin (FX), a xanthophyll carotenoid abundant in marine algae, has attracted widespread attention as a promising alternative candidate for tumor prevention and treatment. Twist is a pivotal regulator of epithelial to mesenchymal transition, and its depletion has proven to sensitize antitumor drugs, inhibit metastasis, reduce CAFs activation and the following interstitial deposition, and increase tumor perfusion. The nanodrug delivery system co-encapsulating FX and nucleic acid drug Twist siRNA (siTwist) was expected to form a potent anti-TNBC therapeutic cyclical feedback loop.

METHODS AND RESULTS

Herein, our studies constituted a novel self-assembled polymer nanomedicine (siTwist/FX@HES-CH) based on the amino-modified hydroxyethyl starch (HES-NH2) grafted with hydrophobic segment cholesterol (CH). The MTT assay, flow cytometry apoptosis analysis, transwell assay, western blot, and 3D multicellular tumor spheroids growth inhibition assay all showed that siTwist/FX@HES-CH could kill tumor cells and inhibit their metastasis in a synergistic manner. The in vivo anti-TNBC efficacy was demonstrated that siTwist/FX@HES-CH remodeled tumor microenvironment, facilitated interstitial barrier crossing, killed tumor cells synergistically, drastically reduced TNBC orthotopic tumor burden and inhibited lung metastasis.

CONCLUSION

Systematic studies revealed that this dual-functional nanomedicine that targets both tumor cells and tumor microenvironment significantly alleviates TNBC orthotopic tumor burden and inhibits lung metastasis, establishing a new paradigm for TNBC therapy.

Tumor Cell-Associated IL-1α Affects Breast Cancer Progression and Metastasis in Mice through Manipulation of the Tumor Immune Microenvironment

IL-1α is a dual function cytokine that affects inflammatory and immune responses and plays a pivotal role in cancer. The effects of intracellular IL-1α on the development of triple negative breast cancer (TNBC) in mice were assessed using the CRISPR/Cas9 system to suppress IL-1α expression in 4T1 breast cancer cells. Knockout of IL-1α in 4T1 cells modified expression of multiple genes, including downregulation of cytokines and chemokines involved in the recruitment of tumor-associated pro-inflammatory cells. Orthotopical injection of IL-1α knockout (KO) 4T1 cells into BALB/c mice led to a significant decrease in local tumor growth and lung metastases, compared to injection of wild-type 4T1 (4T1/WT) cells. Neutrophils and myeloid-derived suppressor cells were abundant in tumors developing after injection of 4T1/WT cells, whereas more antigen-presenting cells were observed in the tumor microenvironment after injection of IL-1α KO 4T1 cells. This switch correlated with increased infiltration of CD3+CD8+ and NKp46+cells. Engraftment of IL-1α knockout 4T1 cells into immunodeficient NOD.SCID mice resulted in more rapid tumor growth, with increased lung metastasis in comparison to engraftment of 4T1/WT cells. Our results suggest that tumor-associated IL-1α is involved in TNBC progression in mice by modulating the interplay between immunosuppressive pro-inflammatory cells vs. antigen-presenting and cytotoxic cells.

Sialic Acid Conjugate-Modified Cationic Liposomal Paclitaxel for Targeted Therapy of Lung Metastasis in Breast Cancer: What a Difference the Cation Content Makes

Cationic lipids play a pivotal role in developing novel drug delivery systems for diverse biomedical applications, owing to the success of mRNA vaccines against COVID-19 and the Phase III antitumor agent EndoTAG-1. However, the therapeutic potential of these positively charged liposomes is limited by dose-dependent toxicity. While an increased content of cationic lipids in the formulation can enhance the uptake and cytotoxicity toward tumor-associated cells, it is crucial to balance these advantages with the associated toxic side effects. In this work, we synthesized the cationic lipid HC-Y-2 and incorporated it into sialic acid (SA)-modified cationic liposomes loaded with paclitaxel to target tumor-associated immune cells efficiently. The SA-modified cationic liposomes exhibited enhanced binding affinity toward both RAW264.7 cells and 4T1 tumor cells in vitro due to the increased ratios of cationic HC-Y-2 content while effectively inhibiting 4T1 cell lung metastasis in vivo. By leveraging electrostatic forces and ligand-receptor interactions, the SA-modified cationic liposomes specifically target malignant tumor-associated immune cells such as tumor-associated macrophages (TAMs), reduce the proportion of cationic lipids in the formulation, and achieve dual objectives: high cellular uptake and potent antitumor efficacy. These findings highlight the potential advantages of this innovative approach utilizing cationic liposomes.

An in situ forming gel co-loaded with pirarubicin and celecoxib inhibits postoperative recurrence and metastasis of breast cancer

Surgical removal combined with postoperative chemotherapy is still the mainstay of treatment for most solid tumors. Although chemotherapy reduces the risk of recurrence and metastasis after surgery, it may produce serious adverse effects and impair patient compliance. In situ drug delivery systems are promising tools for postoperative cancer treatment, improving drug delivery efficiency and reducing side effects. Herein, an injectable phospholipid-based in situ forming gel (IPG) was prepared for the co-delivery of antitumor agent pirarubicin (THP) and cyclooxygenase-2 (COX-2) inhibitor celecoxib (CXB) in the surgical incision, and the latter are used extensively in adjuvant chemotherapy for cancer. After injection, the IPG co-loaded with THP and CXB (THP-CXB-IPG) underwent spontaneous phase transition and formed a drug reservoir that fitted the irregular surgical incisions perfectly. In vitro drug release studies and in vivo pharmacokinetic analysis had demonstrated the sustained release behaviors of THP-CXB-IPG. The in vivo therapeutic efficacy was evaluated in mice that had undergone surgical resection of breast cancer, and the THP-CXB-IPG showed considerable inhibition of residual tumor growth after surgery and reduced the incidence of pulmonary metastasis. Moreover, it reduced the systemic toxicity of chemotherapeutic agents. Therefore, THP-CXB-IPG can be a promising candidate for preventing postoperative recurrence and metastasis.

Formulation of Carnosic-Acid-Loaded Polymeric Nanoparticles: An Attempt to Endorse the Bioavailability and Anticancer Efficacy of Carnosic Acid against Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is considered to be one of the most difficult subtypes of breast cancer (BC) to treat. The sheer absence of certain receptors makes it very tough to target, leaving high-dose chemotherapy as probably the sole therapeutic option at the cost of nonspecific toxic effects. Carnosic acid (CA) has been established as a potential chemotherapeutic agent against a range of cancer cells. However, its in vivo chemotherapeutic potential is significantly challenged due to its poor pharmacokinetic attributes. In this study, poly(lactic-co-glycolic) acid (PLGA) nanoparticles (NPs) were formulated to circumvent the biopharmaceutical limitations of CA. CA-loaded polymeric NPs (CA-PLGA NPs) have been evaluated as a potential therapeutic option in the treatment of TNBC. Different in vitro studies exhibited that CA-PLGA NPs significantly provoked oxidative-stress-mediated apoptotic death in MDA-MB-231 cells. The improved anticancer potential of CA-PLGA NPs over CA was found to be associated with improved cellular uptake of the nanoformulation by TNBC cells. In vivo studies also established the improvement in the chemotherapeutic efficacy of CA-nanoformulation over that of free CA without showing any sign of systemic toxicity. Thus, CA-PLGA NPs emerge as a promising candidate to fix two bugs with a single code, resolving biopharmaceutical attributes of CA as well as introducing a treatment option for TNBC.

Downregulation of IRF8 in alveolar macrophages by G-CSF promotes metastatic tumor progression

Tissue-resident macrophages (TRMs) are abundant immune cells within pre-metastatic sites, yet their functional contributions to metastasis remain incompletely understood. Here, we show that alveolar macrophages (AMs), the main TRMs of the lung, are susceptible to downregulation of the immune stimulatory transcription factor IRF8, impairing anti-metastatic activity in models of metastatic breast cancer. G-CSF is a key tumor-associated factor (TAF) that acts upon AMs to reduce IRF8 levels and facilitate metastasis. Translational relevance of IRF8 downregulation was observed among macrophage precursors in breast cancer and a CD68hiIRF8loG-CSFhi gene signature suggests poorer prognosis in triple-negative breast cancer (TNBC), a G-CSF-expressing subtype. Our data highlight the underappreciated, pro-metastatic roles of AMs in response to G-CSF and identify the contribution of IRF8-deficient AMs to metastatic burden. AMs are an attractive target of local neoadjuvant G-CSF blockade to recover anti-metastatic activity.

MiR-200c reprograms fibroblasts to recapitulate the phenotype of CAFs in breast cancer progression

Mesenchymal-epithelial plasticity driving cancer progression in cancer-associated fibroblasts (CAFs) is undetermined. This work identifies a subgroup of CAFs in human breast cancer exhibiting mesenchymal-to-epithelial transition (MET) or epithelial-like profile with high miR-200c expression. MiR-200c overexpression in fibroblasts is sufficient to drive breast cancer aggressiveness. Oxidative stress in the tumor microenvironment induces miR-200c by DNA demethylation. Proteomics, RNA-seq and functional analyses reveal that miR-200c is a novel positive regulator of NFκB-HIF signaling via COMMD1 downregulation and stimulates pro-tumorigenic inflammation and glycolysis. Reprogramming fibroblasts toward MET via miR-200c reduces stemness and induces a senescent phenotype. This pro-tumorigenic profile in CAFs fosters carcinoma cell resistance to apoptosis, proliferation and immunosuppression, leading to primary tumor growth, metastases, and resistance to immuno-chemotherapy. Conversely, miR-200c inhibition in fibroblasts restrains tumor growth with abated oxidative stress and an anti-tumorigenic immune environment. This work determines the mechanisms by which MET in CAFs via miR-200c transcriptional enrichment with DNA demethylation triggered by oxidative stress promotes cancer progression. CAFs undergoing MET trans-differentiation and senescence coordinate heterotypic signaling that may be targeted as an anti-cancer strategy.

Decreased Lung Metastasis in Triple Negative Breast Cancer Following Locally Delivered Supratherapeutic Paclitaxel-Loaded Polyglycerol Carbonate Nanoparticle Therapy

Breast cancer is among the most prevalent malignancies, accounting for 685,000 deaths worldwide in 2020, largely due to its high metastatic potential. Depending on the stage and tumor characteristics, treatment involves surgery, chemotherapy, targeted biologics, and/or radiation therapy. However, current treatments are insufficient for treating or preventing metastatic disease. Herein, we describe supratherapeutic paclitaxel-loaded nanoparticles (81 wt % paclitaxel) to treat the primary tumor and reduce the risk of subsequent metastatic lesions in the lungs. Primary tumor volume and lung metastasis are reduced by day 30, compared to the paclitaxel clinical standard treatment. The ultrahigh levels of paclitaxel afford an immunotherapeutic effect, increasing natural killer cell activation and decreasing NETosis in the lung, which limits the formation of metastatic lesions.

FGFR1 Signaling Facilitates Obesity-Driven Pulmonary Outgrowth in Metastatic Breast Cancer

Survival of dormant, disseminated breast cancer cells contributes to tumor relapse and metastasis. Women with a body mass index greater than 35 have an increased risk of developing metastatic recurrence. Herein, we investigated the effect of diet-induced obesity (DIO) on primary tumor growth and metastatic progression using both metastatic and systemically dormant mouse models of breast cancer. This approach led to increased PT growth and pulmonary metastasis. We developed a novel protocol to induce obesity in Balb/c mice by combining dietary and hormonal interventions with a thermoneutral housing strategy. In contrast to standard housing conditions, ovariectomized Balb/c mice fed a high-fat diet under thermoneutral conditions became obese over a period of 10 weeks, resulting in a 250% gain in fat mass. Obese mice injected with the D2.OR model developed macroscopic pulmonary nodules compared with the dormant phenotype of these cells in mice fed a control diet. Analysis of the serum from obese Balb/c mice revealed increased levels of FGF2 as compared with lean mice. We demonstrate that serum from obese animals, exogenous FGF stimulation, or constitutive stimulation through autocrine and paracrine FGF2 is sufficient to break dormancy and drive pulmonary outgrowth. Blockade of FGFR signaling or specific depletion of FGFR1 prevented obesity-associated outgrowth of the D2.OR model.

IMPLICATIONS

Overall, this study developed a novel DIO model that allowed for demonstration of FGF2:FGFR1 signaling as a key molecular mechanism connecting obesity to breakage of systemic tumor dormancy and metastatic progression.

CD5 blockade, a novel immune checkpoint inhibitor, enhances T cell anti-tumour immunity and delays tumour growth in mice harbouring poorly immunogenic 4T1 breast tumour homografts

CD5 is a member of the scavenger receptor cysteine-rich superfamily that is expressed on T cells and a subset of B cells (B1a) cell and can regulate the T cell receptor signaling pathway. Blocking CD5 function may have therapeutic potential in treatment of cancer by enhancing cytotoxic T lymphocyte recognition and ablation of tumour cells. The effect of administering an anti-CD5 antibody to block or reduce CD5 function as an immune checkpoint blockade to enhance T cell anti-tumour activation and function in vivo has not been explored. Here we challenged mice with poorly immunogenic 4T1 breast tumour cells and tested whether treatment with anti-CD5 monoclonal antibodies (MAb) in vivo could enhance non-malignant T cell anti-tumour immunity and reduce tumour growth. Treatment with anti-CD5 MAb resulted in an increased fraction of CD8+ T cells compared to CD4+ T cell in draining lymph nodes and the tumour microenvironment. In addition, it increased activation and effector function of T cells isolated from spleens, draining lymph nodes, and 4T1 tumours. Furthermore, tumour growth was delayed in mice treated with anti-CD5 MAb. These data suggest that use of anti-CD5 MAb as an immune checkpoint blockade can both enhance activation of T cells in response to poorly immunogenic antigens and reduce tumour growth in vivo. Exploration of anti-CD5 therapies in treatment of cancer, alone and in combination with other immune therapeutic drugs, is warranted.

A phase I trial of SON-1010, a tumor-targeted, interleukin-12-linked, albumin-binding cytokine, shows favorable pharmacokinetics, pharmacodynamics, and safety in healthy volunteers

Background

The benefits of recombinant interleukin-12 (rIL-12) as a multifunctional cytokine and potential immunotherapy for cancer have been sought for decades based on its efficacy in multiple mouse models. Unexpected toxicity in the first phase 2 study required careful attention to revised dosing strategies. Despite some signs of efficacy since then, most rIL-12 clinical trials have encountered hurdles such as short terminal elimination half-life (T½), limited tumor microenvironment targeting, and substantial systemic toxicity. We developed a strategy to extend the rIL-12 T½ that depends on binding albumin in vivo to target tumor tissue, using single-chain rIL-12 linked to a fully human albumin binding (FHAB) domain (SON-1010). After initiating a dose-escalation trial in patients with cancer (SB101), a randomized, double-blind, placebo-controlled, single-ascending dose (SAD) phase 1 trial in healthy volunteers (SB102) was conducted.

Methods

SB102 (NCT05408572) focused on safety, tolerability, pharmacokinetic (PK), and pharmacodynamic (PD) endpoints. SON-1010 at 50-300 ng/kg or placebo administered subcutaneously on day 1 was studied at a ratio of 6:2, starting with two sentinels; participants were followed through day 29. Safety was reviewed after day 22, before enrolling the next cohort. A non-compartmental analysis of PK was performed and correlations with the PD results were explored, along with a comparison of the SON-1010 PK profile in SB101.

Results

Participants receiving SON-1010 at 100 ng/kg or higher tolerated the injection but generally experienced more treatment-emergent adverse effects (TEAEs) than those receiving the lowest dose. All TEAEs were transient and no other dose relationship was noted. As expected with rIL-12, initial decreases in neutrophils and lymphocytes returned to baseline by days 9-11. PK analysis showed two-compartment elimination in SB102 with mean T½ of 104 h, compared with one-compartment elimination in SB101, which correlated with prolonged but controlled and dose-related increases in interferon-gamma (IFNγ). There was no evidence of cytokine release syndrome based on minimal participant symptoms and responses observed with other cytokines.

Conclusion

SON-1010, a novel presentation for rIL-12, was safe and well-tolerated in healthy volunteers up to 300 ng/kg. Its extended half-life leads to a prolonged but controlled IFNγ response, which may be important for tumor control in patients.

Clinical trial registration

https://clinicaltrials.gov/study/NCT05408572, identifier NCT05408572.

Tunable PhenoCycler imaging of the murine pre-clinical tumour microenvironments

BACKGROUND

The tumour microenvironment (TME) consists of tumour-supportive immune cells, endothelial cells, and fibroblasts. PhenoCycler, a high-plex single cell spatial biology imaging platform, is used to characterize the complexity of the TME. Researchers worldwide harvest and bank tissues from mouse models which are employed to model a plethora of human disease. With the explosion of interest in spatial biology, these panoplies of archival tissues provide a valuable resource to answer new questions. Here, we describe our protocols for developing tunable PhenoCycler multiplexed imaging panels and describe our open-source data analysis pipeline. Using these protocols, we used PhenoCycler to spatially resolve the TME of 8 routinely employed pre-clinical models of lymphoma, breast cancer, and melanoma preserved as FFPE.

RESULTS

Our data reveal distinct TMEs in the different cancer models that were imaged and show that cell-cell contacts differ depending on the tumour type examined. For instance, we found that the immune infiltration in a murine model of melanoma is altered in cellular organization in melanomas that become resistant to αPD-1 therapy, with depletions in a number of cell-cell interactions.

CONCLUSIONS

This work presents a valuable resource study seamlessly adaptable to any field of research involving murine models. The methodology described allows researchers to address newly formed hypotheses using archival materials, bypassing the new to perform new mouse studies.

Leptin/lipopolysaccharide-treated dendritic cell vaccine improved cellular immune responses in an animal model of breast cancer

PURPOSE

In dendritic cells (DCs), leptin as an immune-regulating hormone, increases the IL-12 generation whereas it reduces the IL-10 production, thus contributing to TH1 cell differentiation. Using a murine model of breast cancer (BC), we evaluated the impacts of the Leptin and/or lipopolysaccharide (LPS)-treated DC vaccine on various T-cell-related immunological markers.

MATERIALS AND METHODS

Tumors were established in mice by subcutaneously injecting 7 × 105 4T1 cells into the right flank. Mice received the DC vaccines pretreated with Leptin, LPS, and both Leptin/LPS, on days 12 and 19 following tumor induction. The animals were sacrificed on day 26 and after that the frequency of the splenic cytotoxic T lymphocytes (CTLs) and TH1 cells; interferon gamma (IFN-γ), interleukin 12 (IL-12) and tumor growth factor beta (TGF-β) generation by tumor lysate-stimulated spleen cells, and the mRNA expression of T-bet, FOXP3 and Granzyme B in the tumors were measured with flow cytometry, ELISA and real-time PCR methods, respectively.

RESULTS

Leptin/LPS-treated mDC group was more efficient in blunting tumor growth (p = .0002), increasing survival rate (p = .001), and preventing metastasis in comparison with the untreated tumor-bearing mice (UT-control). In comparison to the UT-control group, treatment with Leptin/LPS-treated mDC also significantly increased the splenic frequencies of CTLs (p < .001) and TH1 cells (p < .01); promoted the production of IFN-γ (p < .0001) and IL-12 (p < .001) by splenocytes; enhanced the T-bet (p < .05) and Granzyme B (p < .001) expression, whereas decreased the TGF-β and FOXP3 expression (p < .05).

CONCLUSION

Compared to the Leptin-treated mDC and LPS-treated mDC vaccines, the Leptin/LPS-treated mDC vaccine was more effective in inhibiting BC development and boosting immune responses against tumor.

Current views on in vivo models for breast cancer research and related drug development

INTRODUCTION

Animal models play a crucial role in breast cancer research, in particular mice and rats, who develop mammary tumors that closely resemble their human counterparts. These models allow the study of mechanisms behind breast carcinogenesis, as well as the efficacy and safety of new, and potentially more effective and advantageous therapeutic approaches. Understanding the advantages and disadvantages of each model is crucial to select the most appropriate one for the research purpose.

AREA COVERED

This review provides a concise overview of the animal models available for breast cancer research, discussing the advantages and disadvantages of each one for searching new and more effective approaches to treatments for this type of cancer.

EXPERT OPINION

Rodent models provide valuable information on the genetic alterations of the disease, the tumor microenvironment, and allow the evaluation of the efficacy of chemotherapeutic agents. However, in vivo models have limitations, and one of them is the fact that they do not fully mimic human diseases. Choosing the most suitable model for the study purpose is crucial for the development of new therapeutic agents that provide better care for breast cancer patients.

Transplantable Murine Tumors in the Studies of Peptide Antitumor Vaccines

Numerous studies have shown that antitumor vaccines based on synthetic peptides are safe and can induce both CD8+ and CD4+ tumor-specific T cell responses. However, clinical results are still scarce, and such approach to antitumor treatment has not gained a wide implication, yet. Recently, particular advances have been achieved due to tumor sequencing and the search for immunogenic neoantigens caused by mutations. One of the most important issues for peptide vaccines, along with the choice of optimal adjuvants and vaccination regimens, is the search for effective target antigens. Extensive studies of peptide vaccines, including those on murine models, are required to reveal the effective vaccine constructs. The review presents transplantable murine tumors with the detected peptides that showed antitumor efficacy as a vaccine compound.

Determination of In Vitro and In Vivo Effects of Taxifolin and Epirubicin on Epithelial-Mesenchymal Transition in Mouse Breast Cancer Cells

Background: One of the most significant characteristics of cancer is epithelial-mesenchymal transition and research on the relationship between phenolic compounds and anticancer medications and epithelial-mesenchymal transition is widespread. Methods: In order to investigate the potential effects of Taxifolin on enhancing the effectiveness of Epirubicin in treating breast cancer, specifically in 4T1 cells and an allograft BALB/c model, the effects of Taxifolin and Epirubicin, both individually and in combination, were examined. Cell viability assays and cytotoxicity assays in 4T1 cells were performed. In addition, 4T1 cells were implanted into female BALB/c mice to conduct in vivo studies and evaluate the therapeutic efficacy of Taxifolin and Epirubicin alone or in combination. Tumor volumes and histological analysis were also assessed in mice. To further understand the mechanisms involved, we examined the messenger RNA and protein levels of epithelial-mesenchymal transition-related genes, as well as active Caspase-3/7 levels, using quantitative real-time polymerase chain reaction, western blot, and enzyme-linked immunosorbent assays, respectively. Results: In vitro results demonstrated that the coadministration of Taxifolin and Epirubicin reduced cell viability and cytotoxicity in 4T1 cell lines. In vivo, coadministration of Taxifolin and Epirubicin suppressed tumor growth in BALB/c mice with 4T1 breast cancer cells. Additionally, this combination treatment significantly increased the levels of active caspase-3/7 and downregulated the messenger RNA and protein levels of N-cadherin, β-catenin, vimentin, snail, and slug, but upregulated the E-cadherin gene. It significantly decreased the messenger RNA levels of the Zeb1 and Zeb2 genes. Conclusion: The in vitro and in vivo results of our study indicate that the concurrent use of Epirubicin with Taxifolin has supportive effects on breast cancer treatment.

Targeting Breast Cancer with N-Acetyl-D-Glucosamine: Integrating Machine Learning and Cellular Assays for Promising Results

BACKGROUND

Breast cancer is a common cancer with high mortality rates. Early diagnosis is crucial for reducing the prognosis and mortality rates. Therefore, the development of alternative treatment options is necessary.

OBJECTIVE

This study aimed to investigate the inhibitory effect of N-acetyl-D-glucosamine (D-GlcNAc) on breast cancer using a machine learning method. The findings were further confirmed through assays on breast cancer cell lines.

METHODS

MCF-7 and 4T1 cell lines (ATCC) were cultured in the presence and absence of varying concentrations of D-GlcNAc (0.5 mM, 1 mM, 2 mM, and 4 mM) for 72 hours. A xenograft mouse model for breast cancer was established by injecting 4T1 cells into mammary glands. D-GlcNAc (2 mM) was administered intraperitoneally to mice daily for 28 days, and histopathological effects were evaluated at pre-tumoral and post-tumoral stages.

RESULTS

Treatment with 2 mM and 4 mM D-GlcNAc significantly decreased cell proliferation rates in MCF-7 and 4T1 cell lines and increased Fas expression. The number of apoptotic cells was significantly higher than untreated cell cultures (p < 0.01 - p < 0.0001). D-GlcNAc administration also considerably reduced tumour size, mitosis, and angiogenesis in the post-treatment group compared to the control breast cancer group (p < 0.01 - p < 0.0001). Additionally, molecular docking/dynamic analysis revealed a high binding affinity of D-GlcNAc to the marker protein HER2, which is involved in tumour progression and cell signalling.

CONCLUSION

Our study demonstrated the positive effect of D-GlcNAc administration on breast cancer cells, leading to increased apoptosis and Fas expression in the malignant phenotype. The binding affinity of D-GlcNAc to HER2 suggests a potential mechanism of action. These findings contribute to understanding D-GlcNAc as a potential anti-tumour agent for breast cancer treatment.

Cellular Context Dictates the Suppression or Augmentation of Triple-Negative Mammary Tumor Metastasis by NLRX1

Prior studies have defined multiple, but inconsistent, roles for the enigmatic pattern recognition receptor NLRX1 in regulating several cancer-associated biological functions. In this study, we explore the role of NLRX1 in the highly metastatic murine 4T1 mammary tumor model. We describe a functional dichotomy of NLRX1 between two different cellular contexts: expression in healthy host cells versus expression in the 4T1 tumor cells. Using Nlrx1-/- mice engrafted with 4T1 tumors, we demonstrate that NLRX1 functions as a tumor suppressor when expressed in the host cells. Specifically, NLRX1 in healthy host cells attenuates tumor growth and lung metastasis through suppressing characteristics of epithelial-mesenchymal transition and the lung metastatic niche. Conversely, we demonstrate that NLRX1 functions as a tumor promoter when expressed in 4T1 tumor cells using gain- and loss-of-function studies both in vitro and in vivo. Mechanistically, NLRX1 in the tumor cells augments 4T1 aggressiveness and metastasis through regulating epithelial-mesenchymal transition hallmarks, cell death, proliferation, migration, reactive oxygen species levels, and mitochondrial respiration. Collectively, we provide critical insight into NLRX1 function and establish a dichotomous role of NLRX1 in the 4T1 murine mammary carcinoma model that is dictated by cellular context.

In Situ Insonation of Alkaline Buffer Containing Liposomes Leads to a Net Improvement of the Therapeutic Outcome in a Triple Negative Breast Cancer Murine Model

Breast cancer is characterized by an acidic micro-environment. Acidic extracellular pH gives cancer cells an evolutionary advantage, hence, neutralization of the extracellular pH has been considered as a potential therapeutic strategy. To address the issue of systemic pH alteration, an approach based on the targeted delivery of the buffering solution to the tumor region is investigated. The method relies on the use of low frequency ultrasound and sono-sensitive liposomes loaded with buffers at alkaline pH (LipHUS). After the i.v. injection of LipHUS, the application of ultrasound (US) at the sites of the pathology induces a local increase of pH that results highly effective in i) inhibiting primary tumor growth, ii) reducing tumor recurrence after surgery, and iii) suppressing metastases' formation. The experiments are carried out on a triple negative breast cancer mouse model. The results obtained demonstrate that localized and triggered release of bicarbonate or PBS buffer from sonosensitive liposomes represents an efficient therapeutic tool for treating triple-negative breast cancer. This approach holds promise for potential clinical translation.

In vivo selection of synthetic nucleocapsids for tissue targeting

Controlling the biodistribution of protein- and nanoparticle-based therapeutic formulations remains challenging. In vivo library selection is an effective method for identifying constructs that exhibit desired distribution behavior; library variants can be selected based on their ability to localize to the tissue or compartment of interest despite complex physiological challenges. Here, we describe further development of an in vivo library selection platform based on self-assembling protein nanoparticles encapsulating their own mRNA genomes (synthetic nucleocapsids or synNCs). We tested two distinct libraries: a low-diversity library composed of synNC surface mutations (45 variants) and a high-diversity library composed of synNCs displaying miniproteins with binder-like properties (6.2 million variants). While we did not identify any variants from the low-diversity surface library that yielded therapeutically relevant changes in biodistribution, the high-diversity miniprotein display library yielded variants that shifted accumulation toward lungs or muscles in just two rounds of in vivo selection. Our approach should contribute to achieving specific tissue homing patterns and identifying targeting ligands for diseases of interest.

Combination of verteporfin-photodynamic therapy with 5-aza-2'-deoxycytidine enhances the anti-tumour immune response in triple negative breast cancer

Introduction

Triple negative breast cancer (TNBC) is a subtype of breast cancer characterised by its high tumourigenic, invasive, and immunosuppressive nature. Photodynamic therapy (PDT) is a focal therapy that uses light to activate a photosensitizing agent and induce a cytotoxic effect. 5-aza-2'-deoxycytidine (5-ADC) is a clinically approved immunomodulatory chemotherapy agent. The mechanism of the combination therapy using PDT and 5-ADC in evoking an anti-tumour response is not fully understood.

Methods

The present study examined whether a single dose of 5-ADC enhances the cytotoxic and anti-tumour immune effect of low dose PDT with verteporfin as the photosensitiser in a TNBC orthotopic syngeneic murine model, using the triple negative murine mammary tumour cell line 4T1. Histopathology analysis, digital pathology and immunohistochemistry of treated tumours and distant sites were assessed. Flow cytometry of splenic and breast tissue was used to identify T cell populations. Bioinformatics were used to identify tumour immune microenvironments related to TNBC patients.

Results

Functional experiments showed that PDT was most effective when used in combination with 5-ADC to optimize its efficacy. 5-ADC/PDT combination therapy elicited a synergistic effect in vitro and was significantly more cytotoxic than monotherapies on 4T1 tumour cells. For tumour therapy, all types of treatments demonstrated histopathologically defined margins of necrosis, increased T cell expression in the spleen with absence of metastases or distant tissue destruction. Flow cytometry and digital pathology results showed significant increases in CD8 expressing cells with all treatments, whereas only the 5-ADC/PDT combination therapy showed increase in CD4 expression. Bioinformatics analysis of in silico publicly available TNBC data identified BCL3 and BCL2 as well as the following anti-tumour immune response biomarkers as significantly altered in TNBC compared to other breast cancer subtypes: GZMA, PRF1, CXCL1, CCL2, CCL4, and CCL5. Interestingly, molecular biomarker assays showed increase in anti-tumour response genes after treatment. The results showed concomitant increase in BCL3, with decrease in BCL2 expression in TNBC treatment. In addition, the treatments showed decrease in PRF1, CCL2, CCL4, and CCL5 genes with 5-ADC and 5-ADC/PDT treatment in both spleen and breast tissue, with the latter showing the most decrease.

Discussion

To our knowledge, this is the first study that shows which of the innate and adaptive immune biomarkers are activated during PDT related treatment of the TNBC 4T1 mouse models. The results also indicate that some of the immune response biomarkers can be used to monitor the effectiveness of PDT treatment in TNBC murine model warranting further investigation in human subjects.

Biogenic synthesis of gold nanoparticles using dual extract of tulsi-Vinca for breast cancer tumor regression in mice

Aim: This work aims to synthesize the gold nanoparticles (GNPs) using a dual extract of tulsi and Vinca (T+V-Gold) for breast cancer tumor regression. Methods: The GNPs were synthesized and characterized for their microscopic, spectroscopic and crystalline properties. Further, the GNPs were investigated for in vitro and in vivo studies for the treatment of the 4T1-induced triple-negative breast cancer murine model. Results: The GNPs for 4T1 tumor-challenged mice resulted in delayed tumor development and lower tumor burden, with T+V-Gold demonstrating the highest prevention of tumor spread. The antitumor effect of T+V-Gold is highly significant in the glutathione family antioxidants glutathione S-transferase and glutathione in tumor tissue samples. Conclusion: The bioefficacy and anticancer outcomes of T+V-Gold nanoformulation can be used as therapeutic agents and drug-delivery vehicles.

Vitamin B5 supports MYC oncogenic metabolism and tumor progression in breast cancer

Tumors are intrinsically heterogeneous and it is well established that this directs their evolution, hinders their classification and frustrates therapy1-3. Consequently, spatially resolved omics-level analyses are gaining traction4-9. Despite considerable therapeutic interest, tumor metabolism has been lagging behind this development and there is a paucity of data regarding its spatial organization. To address this shortcoming, we set out to study the local metabolic effects of the oncogene c-MYC, a pleiotropic transcription factor that accumulates with tumor progression and influences metabolism10,11. Through correlative mass spectrometry imaging, we show that pantothenic acid (vitamin B5) associates with MYC-high areas within both human and murine mammary tumors, where its conversion to coenzyme A fuels Krebs cycle activity. Mechanistically, we show that this is accomplished by MYC-mediated upregulation of its multivitamin transporter SLC5A6. Notably, we show that SLC5A6 over-expression alone can induce increased cell growth and a shift toward biosynthesis, whereas conversely, dietary restriction of pantothenic acid leads to a reversal of many MYC-mediated metabolic changes and results in hampered tumor growth. Our work thus establishes the availability of vitamins and cofactors as a potential bottleneck in tumor progression, which can be exploited therapeutically. Overall, we show that a spatial understanding of local metabolism facilitates the identification of clinically relevant, tractable metabolic targets.

Albumin Nanoparticles Surface Decorated with a Tumor-Homing Peptide Help in Selective Killing of Triple-Negative Breast Cancer Cells

In this article, we describe a method of delivery of doxorubicin using a novel tumor-homing peptide-based albumin nanoparticle system to triple-negative breast cancer cells (TNBC). The absence and reduced expression of the hormone (estrogen, progesterone) and HER2 (human epidermal growth factor 2) receptors, respectively, render TNBC patients nonsusceptible to different available targeted therapies. These peptide-modified nanoparticles could be taken up by TNBC cells more effectively than their bare counterparts. The drug-loaded peptide-modified nanoparticles achieved an optimal but crucial balance between cell killing in cancerous cells and cell survival in the noncancerous ones. This appears to be because of different routes of entry and subsequent fate of the bare and peptide-modified nanoparticles in cancerous and noncancerous cells. In a TNBC mouse model, the peptide-modified system fared better than the free drug in mounting an antitumor response while not being toxic systemically.

Adiponectin-expressing Treg-containing T cell fraction inhibits tumor growth in orthotopically implanted triple-negative breast cancer

BACKGROUND

In our previous study, we identified a population of adiponectin expressing regulatory T cells (Tregs) residing within thymic nurse cell complexes, which were capable of inhibiting the development of breast cancer in vitro. Triple-negative breast cancer (TNBC) with no proper treatment at present is characterized by the absence of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor-2. In this study, we aimed to investigate the potential of a cultured T cell fraction comprising adiponectin-expressing Tregs, referred to as A-TregTF (adiponectin-expressing Treg-containing T cell fraction), in inhibiting the progression of TNBC in vivo.

METHODS

The efficacy of a spontaneously expanding T cell fraction comprising adiponectin-expressing Treg in inhibiting tumor growth was analyzed in a murine orthotopic 4 T1-Luc TNBC model.

RESULTS

The treatment with T cell fraction containing adiponectin-expressing Tregs significantly inhibited the growth and metastasis of orthotopically transplanted 4 T1-Luc tumor cells. Histopathological examination further revealed that the adiponectin-expressing Tregs infiltrated the tumor tissue via a cell-in-cell mechanism and were found to be specifically localized around the necrotic areas.

CONCLUSIONS

Based on our findings, the T cell fraction comprising adiponectin-expressing Tregs, represents a potential candidate for adoptive cell therapy against TNBC.

Cystine/glutamate antiporter xCT deficiency reduces metastasis without impairing immune system function in breast cancer mouse models

BACKGROUND

The upregulation of antioxidant mechanisms is a common occurrence in cancer cells, as they strive to maintain balanced redox state and prevent oxidative damage. This includes the upregulation of the cystine/glutamate antiporter xCT, which plays a crucial role in protecting cancer cells from oxidative stress. Consequently, targeting xCT has become an attractive strategy for cancer treatment. However, xCT is also expressed by several types of immune cells where it has a role in proliferation and effector functions. In light of these observations, a comprehensive understanding of the specific role of xCT in the initiation and progression of cancer, as well as its potential impact on the immune system within the tumor microenvironment and the anti-tumor response, require further investigation.

METHODS

We generated xCTnull BALB/c mice to investigate the role of xCT in the immune system and xCTnull/Erbb2-transgenic BALB-neuT mice to study the role of xCT in a mammary cancer-prone model. We also used mammary cancer cells derived from BALB-neuT/xCTnull mice and xCTKO 4T1 cells to test the contribution of xCT to malignant properties in vitro and in vivo.

RESULTS

xCT depletion in BALB-neuT/xCTnull mice does not alter autochthonous tumor initiation, but tumor cells isolated from these mice display proliferation and redox balance defects in vitro. Although xCT disruption sensitizes 4T1 cells to oxidative stress, it does not prevent transplantable tumor growth, but reduces cell migration in vitro and lung metastasis in vivo. This is accompanied by an altered immune cell recruitment in the pre-metastatic niche. Finally, systemic depletion of xCT in host mice does not affect transplantable tumor growth and metastasis nor impair the proper mounting of both humoral and cellular immune responses in vivo.

CONCLUSIONS

xCT is dispensable for proper immune system function, thus supporting the safety of xCT targeting in oncology. Nevertheless, xCT is involved in several processes required for the metastatic seeding of mammary cancer cells, thus broadening the scope of xCT-targeting approaches.

Hyperbranched Polymer Dots with Strong Absorption and High Fluorescence Quantum Yield for In Vivo NIR-II Imaging

In order to improve the fluorescence quantum yield (QY) of NIR-II-emitting nanoparticles, D-A-D fluorophores are typically linked to intramolecular rotatable units to reduce aggregation-induced quenching. However, incorporating such units often leads to a twisted molecular backbone, which affects the coupling within the D-A-D unit and, as a result, lowers the absorption. Here, we overcome this limitation by cross-linking the NIR-II fluorophores to form a 2D polymer network, which simultaneously achieves a high QY by well-controlled fluorophore separation and strong absorption by restricting intramolecular distortion. Using the strategy, we developed polymer dots with the highest NIR-II single-particle brightness among reported D-A-D-based nanoparticles and applied them for imaging of hindlimb vasculatures and tumors as well as fluorescence-guided tumor resection. The high brightness of the polymer dots offered exceptional image quality and excellent surgical results, showing a promising performance for these applications.

Can Exercise Enhance the Efficacy of Checkpoint Inhibition by Modulating Anti-Tumor Immunity?

Immune checkpoint inhibition (ICI) has revolutionized cancer therapy. However, response to ICI is often limited to selected subsets of patients or not durable. Tumors that are non-responsive to checkpoint inhibition are characterized by low anti-tumoral immune cell infiltration and a highly immunosuppressive tumor microenvironment. Exercise is known to promote immune cell circulation and improve immunosurveillance. Results of recent studies indicate that physical activity can induce mobilization and redistribution of immune cells towards the tumor microenvironment (TME) and therefore enhance anti-tumor immunity. This suggests a favorable impact of exercise on the efficacy of ICI. Our review delivers insight into possible molecular mechanisms of the crosstalk between muscle, tumor, and immune cells. It summarizes current data on exercise-induced effects on anti-tumor immunity and ICI in mice and men. We consider preclinical and clinical study design challenges and discuss the role of cancer type, exercise frequency, intensity, time, and type (FITT) and immune sensitivity as critical factors for exercise-induced impact on cancer immunosurveillance.

Radiolabeled Human Serum Albumin Nanoparticles Co-Loaded with Methotrexate and Decorated with Trastuzumab for Breast Cancer Diagnosis

Breast cancer is a leading cause of cancer-related mortality among women worldwide, with millions of new cases diagnosed yearly. Addressing the burden of breast cancer mortality requires a comprehensive approach involving early detection, accurate diagnosis, effective treatment, and equitable access to healthcare services. In this direction, nano-radiopharmaceuticals have shown potential for enhancing breast cancer diagnosis by combining the benefits of nanoparticles and radiopharmaceutical agents. These nanoscale formulations can provide improved imaging capabilities, increased targeting specificity, and enhanced sensitivity for detecting breast cancer lesions. In this study, we developed and evaluated a novel nano-radio radiopharmaceutical, technetium-99m ([99mTc]Tc)-labeled trastuzumab (TRZ)-decorated methotrexate (MTX)-loaded human serum albumin (HSA) nanoparticles ([99mTc]-TRZ-MTX-HSA), for the diagnosis of breast cancer. In this context, HSA and MTX-HSA nanoparticles were prepared. Conjugation of MTX-HSA nanoparticles with TRZ was performed using adsorption and covalent bonding methods. The prepared formulations were evaluated for particle size, PDI value, zeta (ζ) potential, scanning electron microscopy analysis, encapsulation efficiency, and loading capacity and cytotoxicity on MCF-7, 4T1, and MCF-10A cells. Finally, the nanoparticles were radiolabeled with [99mTc]Tc using the direct radiolabeling method, and cellular uptake was performed with the nano-radiopharmaceutical. The results showed the formation of spherical nanoparticles, with a particle size of 224.1 ± 2.46 nm, a PDI value of 0.09 ± 0.07, and a ζ potential value of -16.4 ± 0.53 mV. The encapsulation efficiency of MTX was found to be 32.46 ± 1.12%, and the amount of TRZ was 80.26 ± 1.96%. The labeling with [99mTc]Tc showed a high labeling efficiency (>99%). The cytotoxicity studies showed no effect, and the cellular uptake studies showed 97.54 ± 2.16% uptake in MCF-7 cells at the 120th min and were found to have a 3-fold higher uptake in cancer cells than in healthy cells. In conclusion, [99mTc]Tc-TRZ-MTX-HSA nanoparticles are promising for diagnosing breast cancer and evaluating the response to treatment in breast cancer patients.

The p53 tumor suppressor regulates AKR1B1 expression, a metastasis-promoting gene in breast cancer

Alteration of metabolism in cancer cells is a central aspect of the mechanisms that sustain aggressive traits. Aldo-keto reductase 1 B1 (AKR1B1) catalyzes the reduction of several aldehydes to alcohols consuming NADPH. Nevertheless, the ability of AKR1B1 to reduce different substrates renders difficult to comprehensively ascertain its biological role. Recent evidence has implicated AKR1B1 in cancer; however, the mechanisms underlying its pro-oncogenic function remain largely unknown. In this work, we report that AKR1B1 expression is controlled by the p53 tumor suppressor. We found that breast cancer patients bearing wild-type TP53 have reduced AKR1B1 expression. In cancer cell lines, p53 reduced AKR1B1 mRNA and protein levels and repressed promoter activity in luciferase assays. Furthermore, chromatin immunoprecipitation assays indicated that p53 is recruited to the AKR1B1 promoter. We also observed that AKR1B1 overexpression promoted metastasis in the 4T1 orthotopic model of triple-negative breast cancer. Proteomic analysis of 4T1 cells overexpressing AKR1B1 showed that AKR1B1 exerts a marked effect on proteins related to metabolism, with a particular impact on mitochondrial function. This work provides novel insights on the link between the p53 pathway and metabolism in cancer cells and contributes to characterizing the alterations associated to the pathologic role of AKR1B1.

Radiation-induced photodynamic therapy using calcium tungstate nanoparticles and 5-aminolevulinic acid prodrug

Photodynamic therapy (PDT) using 5-aminolevulinic acid (ALA) prodrug is a clinically tried and proven treatment modality for surface-level lesions. However, its use for deep-seated tumors has been limited due to the poor penetration depth of visible light needed to activate the photosensitizer protoporphyrin IX (PPIX), which is produced from ALA metabolism. Herein, we report the usage of poly(ethylene glycol-b-lactic acid) (PEG-PLA)-encapsulated calcium tungstate (CaWO4, CWO for short) nanoparticles (PEG-PLA/CWO NPs) as energy transducers for X-ray-activated PDT using ALA. Owing to the spectral overlap between radioluminescence afforded by the CWO core and the absorbance of PPIX, these NPs can serve as an in situ visible light activation source during radiotherapy (RT), thereby mitigating the limitation of penetration depth. We demonstrate that this effect is observed across different cell lines with varying radio-sensitivity. Importantly, both PPIX and PEG-PLA/CWO NPs exhibit no significant toxicities at therapeutic doses in the absence of radiation. To assess the efficacy of this approach, we conducted a study using a syngeneic mouse model subcutaneously implanted with inherently radio-resistant 4T1 tumors. The results show a significantly improved prognosis compared to conventional RT, even with as few as 2 fractions of 4 Gy X-rays. Taken together, these results suggest that PEG-PLA/CWO NPs are promising agents for application of ALA-PDT in deep-seated tumors, thereby significantly expanding the utility of the already established treatment strategy.

Cancer cell plasticity and MHC-II-mediated immune tolerance promote breast cancer metastasis to lymph nodes

Tumor-draining lymph nodes (TDLNs) are important for tumor antigen-specific T cell generation and effective anticancer immune responses. However, TDLNs are often the primary site of metastasis, causing immune suppression and worse outcomes. Through cross-species single-cell RNA-Seq analysis, we identified features defining cancer cell heterogeneity, plasticity, and immune evasion during breast cancer progression and lymph node metastasis (LNM). A subset of cancer cells in the lymph nodes exhibited elevated MHC class II (MHC-II) gene expression in both mice and humans. MHC-II+ cancer cells lacked costimulatory molecule expression, leading to regulatory T cell (Treg) expansion and fewer CD4+ effector T cells in TDLNs. Genetic knockout of MHC-II reduced LNM and Treg expansion, while overexpression of the MHC-II transactivator, Ciita, worsened LNM and caused excessive Treg expansion. These findings demonstrate that cancer cell MHC-II expression promotes metastasis and immune evasion in TDLNs.

Low-dose total body irradiation enhances systemic anti-tumor immunity induced by local cryotherapy

BACKGROUND

Strategies that restore the immune system's ability to recognize malignant cells have yielded clinical benefits but only in some patients. Tumor cells survive cryotherapy and produce a vast amount of antigens to trigger innate and adaptive responses. However, because tumor cells have developed immune escape mechanisms, cryotherapy alone may not be enough to induce a significant immune response.

METHODS

The mice were randomly divided into four groups: Group A: low-dose total body irradiation combined with cryotherapy (L-TBI+cryo); Group B: cryotherapy (cryo); Group C: low-dose total body irradiation(L-TBI); Group D: control group (Control). The tumor growth, recurrence, and survival time of mice in each group were compared and the effects of different treatments on systemic anti-tumor immunity were explored.

RESULTS

L-TBI in conjunction with cryotherapy can effectively control tumor regrowth, inhibit tumor lung metastasis, extend the survival time of mice, and stimulate a long-term protective anti-tumor immune response to resist the re-challenge of tumor cells. The anti-tumor mechanism of this combination therapy may be related to the stimulation of inflammatory factors IFN-γ and IL-2, as well as an increase in immune effector cells (CD8+ T cells) and a decrease in immunosuppressive cells (MDSC, Treg cells) in the spleen or tumor tissue.

CONCLUSIONS

We present unique treatment options for enhancing the immune response caused by cryotherapy, pointing to the way forward for cancer treatment.

Breast Cancer Brain Metastases: Implementation and Characterization of a Mouse Model Relying on Malignant Cells Inoculation in the Carotid Artery

Breast cancer (BC) brain metastases (BCBM) is a severe condition frequently occurring in the triple-negative subtype. The study of BCBM pathogenesis and treatment has been hampered by the difficulty in establishing a reliable animal model that faithfully recapitulates the preferential formation of brain metastases. The injection of BC cells in the carotid artery of mice has been proposed but the procedure is challenging, with the metastatic pattern being scarcely characterized. In this work, we thoroughly describe an improved procedure, highlighting the tricks and challenges of the process, and providing a characterization of the brain and peripheral metastatic pattern at the cellular and molecular level. Triple-negative BC (4T1) cells were inoculated in the common carotid artery of BALB/c mice. Brains and peripheral organs were harvested at 7-14 days for the histological characterization of the metastases' pattern and the immunofluorescence analysis of specific markers. With our surgical procedure, both mouse death and procedure-associated weight loss were negligible. Brain metastases mostly occurred in the hippocampus, while sparse peripheral lesions were only detected in the lungs. Brain-colonizing BC cells presented proliferative (Ki-67) and epithelial (pan-cytokeratin and tomato lectin) features, which account for metastases' establishment. The presented surgical approach constitutes an important and reliable tool for BCBM studies.

CXCR4-Targeted Necrosis-Inducing Peptidomimetic for Treating Breast Cancer

Triple-negative breast cancer is an aggressive subtype with a high recurrence rate, potential for metastasis, and a poor prognosis. The chemokine receptor, CXCR4, is a promising molecular target in breast cancer therapy. Here, we have developed a CXCR4-targeted antitumor peptidomimetic (named CTCE-KLAK), which is a fusion of the CXCR4 receptor antagonist CTCE-9908 and the D-form of proapoptotic peptide (KLAKLAK)₂, for the treatment of breast cancer. First, we investigated the in vitro antitumor activity of CTCE-KLAK against various breast cancer cells and noncancerous mammary epithelial cells. CTCE-KLAK showed cell-selective cytotoxicity and induced rapid necrotic cell death in breast cancer cells but not in normal cells. In contrast, unconjugated peptides such as the carboxylate analogues of CTCE-9908 and _D(KLAKLAK)₂ were not cytotoxic to these cells. The tumor selectivity of CTCE-KLAK for cytotoxic activity depends on its internalization into tumor cells. There was no cleavage of caspase-3, caspase-7, or PARP1 in CTCE-KLAK-treated cells. In addition, cell death by CTCE-KLAK was not prevented by z-VAD-fmk, a pan-caspase inhibitor that inhibits cisplatin-induced cell death. These data indicate that the CTCE-KLAK conjugate is a cell-selective inducer of necrosis. Furthermore, we evaluated the in vivo antitumor activity of CTCE-KLAK in the 4T1 mouse metastatic breast cancer model. Intravenous administration of CTCE-KLAK significantly inhibited tumor growth and lung metastasis. Together, these findings suggest that the necrosis-inducing peptidomimetic CTCE-KLAK is a promising CXCR4-targeted agent for treating triple-negative breast cancer.