Treatment landscape of triple-negative breast cancer - expanded options, evolving needs

Tumor vascular normalization by B7-H3 blockade augments T lymphocyte-mediated antitumor immunity

Triple-negative breast cancer (TNBC), defined by the absence of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2), presents unique clinical challenges and generally predicts a less favorable prognosis. Despite recent advancements in TNBC treatment, a subset of patients remains resistant to immunotherapy. B7-H3, a member of the B7 family of immune checkpoints, is correlated with poor outcomes in various cancers and is distinctively expressed in tumor vasculature, marking it as a potential biomarker for tumor-associated endothelial cells. We found high expression of B7-H3 in the endothelial cells of the postoperative tissue of TNBC patients. Elevated gene expression of CD276 (encoding B7-H3) and PECAM1 (encoding CD31) in TNBC is associated with poor prognosis. Anti-B7-H3 blockade reduces tumor burden and promotes lymphocyte infiltration in a TNBC mouse model. Additionally, anti-B7-H3 blockade promotes tumor vessel normalization and enhances programmed cell death ligand 1 (PD-L1) expression. Synergistic effects were observed when B7-H3 blockade was combined with programmed cell death protein 1 (PD-1) inhibition in the TNBC mouse model. Furthermore, anti-B7-H3 inhibits human umbilical vein endothelial cell (HUVEC) proliferation by suppression of the nuclear factor kappa-B (NF-κB) signaling pathway. Downregulation of B7-H3 expression in HUVECs promotes lymphocyte trans-endothelial migration. These findings suggest that B7-H3 represents a promising therapeutic target for TNBC, and the combination of anti-B7-H3 and anti-PD-1 therapies may have synergetic effects in treating TNBC.

Biologically logic-gated Trojan-horse strategy for personalized triple-negative breast cancer precise therapy by selective ferroptosis and STING pathway provoking

Amidst the therapeutic quandaries associated with triple-negative breast cancer (TNBC), an aggressive malignancy distinguished by its immune resistance and limited treatment avenues, the urgent need for innovative solutions is underscored. To conquer the dilemma, we present a groundbreaking approach that ingeniously employs DNA-fragments-containing exosomes (DNA-Exo) and the concept of "biological logic-gates" to achieve precise homing and controlled selective activation of ferroptosis and stimulator interferon genes (STING) pathways. Leveraging insights from our previous research, a nano-Trojan-horse, Fe0@HMON@DNA-Exo, is engineered via in situ Fe0 synthesis within the glutathione (GSH)-responsiveness degradable hollow mesoporous organosilica nanoparticles (HMON) and subsequently enveloped in DNA-Exo derived from 7-ethyl-10-hydroxycamptothecin (SN38)-treated 4T1 cells. Emphasizing the precision of our approach, the DNA-Exo ensures specific 'homing' to TNBC cells, rendering a targeted delivery mechanism. Concurrently, the concept of "biological logic-gates" is employed to dictate a meticulous and selective activation of STING in antigen-presenting cells (APCs) under OR logic-gating with robust immune response and Fe0-based ferroptosis in TNBC cells under AND logic-gating with reactive oxygen species (ROS) storm generation. In essence, our strategy exhibits great potential in transforming the "immunologically cold" nature of TNBC, enabling precise control over cellular responses, illuminating a promising therapeutic paradigm that is comprehensive and productive in pursuing precision oncology and paving the way for personalized TNBC therapies.

In-silico identification and validation of Silibinin as a dual inhibitor for ENO1 and GLUT4 to curtail EMT signaling and TNBC progression

The aberrant metabolic reprogramming endows TNBC cells with sufficient ATP and lactate required for survival and metastasis. Hence, the intervention of the metabolic network represents a promising avenue to alleviate the Warburg effect in TNBC cells to impair their invasive and metastatic potential. Multitudinous in-silico analysis identified Enolase1 (ENO1) and the surface transporter protein, GLUT4 to be the potential targets for the abrogation of the metabolic network. The expression profiles of ENO1 and GLUT4 genes showed anomalous expression in various cancers, including breast cancer. Subsequently, the functional and physiological interactions of the target proteins were analyzed from the protein-protein interaction network. The pathway enrichment analysis identified the prime cancer signaling pathways in which these proteins are involved. Further, docking results bestowed Silibinin as the concurrent inhibitor of ENO1 and GLUT4. Moreover, the stable interaction of Silibinin with both proteins deciphered the binding free energies values of -48.86 and -104.31 KJ/mol from MMPBSA analysis and MD simulation, respectively. Furthermore, the cell viability, ROS assay, and live-dead imaging underscored the pronounced cytotoxicity of Silibinin, illuminating its capacity to incur apoptosis within TNBC cells. Additionally, glycolysis assay and gene expression analysis demonstrated the silibinin-mediated inhibition of the glycolysis pathway. Eventually, a lipidomic reprogramming towards fatty acid metabolism was established from the elevated lipid droplet accumulation, exogenous fatty acid uptake and de-novo lipogenesis. Nevertheless, repression of EMT and Wnt pathway progression by Silibinin was perceived from the gene expression studies. Overall, the current study highlights the tweaking of intricate signaling crosstalk between glycolysis and the Wnt pathway in TNBC cells through inhibiting ENO1 and GLUT4.

Cyclooxygenase-2/prostaglandin E2 inhibition remodulated photodynamic therapy-associated immunosuppression for enhanced cancer immunotherapy

Low immunogenicity and immunosuppressive tumor microenvironment (TME) are two pivotal factors restricting tumor immunotherapy. Photodynamic therapy (PDT) directly destroys cancer cells by producing reactive oxygen species (ROS), and enhances the immunogenicity of "cold" tumors by inducing immunogenic cell death (ICD), thereby promoting T cell development against tumors. However, PDT also deteriorates immunosuppression through overactivating the cyclooxygenase-2/prostaglandin E2 (COX-2/PGE2) pathway. To this end, biocompatible albumin nanoassemblies co-delivering IR780 and diclofenac are herein developed for enhanced therapy against triple-negative breast cancer. PDT-exacerbated PGE2 overexpression is effectively abolished by diclofenac-mediated COX-2 inhibition, which reprograms immunosuppressive TME via downregulating the infiltration of various immunosuppressive cells and their cytokine secretion to enhance effector T cell infiltration. Consequently, the enhanced antitumor immunity effectively inhibits tumor growth, prevents the recurrency and metastasis, and remarkably boosts the treatment efficacy of PD-L1 blockade. This study sets an intriguing example for overcoming the COX-2/PGE2 pathway-exacerbated immunosuppression alongside immune activation, thus enhancing synergistic cancer immunotherapy potentiated by various ROS-producing therapies (e.g., PDT and radiotherapy) and chemotherapy.

A positive-feedback loop suppresses TNBC tumour growth by remodeling tumour immune microenvironment and inducing ferroptosis

Triple-negative breast cancer (TNBC) is a particularly aggressive subtype of breast cancer due to poor immunogenicity and limited immune cell infiltration, efficient therapeutics are still deficiency. Ferroptosis, a reactive oxygen species (ROS)-reliant cell death, can enhance cellular immunogenicity and then active immune system. To sustain a long-term "hot" tumour immune microenvironment (TIME), an immune-modulator is indispensable. Metformin (MET), a commonly used oral drug for type 2 diabetes, has played a vital role in fostering an immunostimulatory environment. Herein, we confirm the TIME can be remodeled by MET and further promotes ferroptosis via upregulating cellular concentration of l-Glutamine. In light of this, we have design a self-assembled MET-loaded Fe3+-doped polydopamine nanoparticle (Fe-PDA-MET NP) that can disorder the cellular redox homeostasis and induce robust ferroptosis under 808 nm irradiation, resulting in a strong immune response. Based on the function of MET, there is a marked increase in the infiltration of activated CD8+ T cells and NK cells, which subsequently augments ferroptosis to a greater extent. Taken together, Fe-PDA-MET NPs activate a ferroptotic positive-feedback loop for effectively control TNBC progression, which offers a promising therapeutic modality to enhance the immunogenicity and reshape the TIME.

Artificial Intelligence and Breast Cancer Management: From Data to the Clinic

Breast cancer (BC) remains a significant threat to women's health worldwide. The oncology field had an exponential growth in the abundance of medical images, clinical information, and genomic data. With its continuous advancement and refinement, artificial intelligence (AI) has demonstrated exceptional capabilities in processing intricate multidimensional BC-related data. AI has proven advantageous in various facets of BC management, encompassing efficient screening and diagnosis, precise prognosis assessment, and personalized treatment planning. However, the implementation of AI into precision medicine and clinical practice presents ongoing challenges that necessitate enhanced regulation, transparency, fairness, and integration of multiple clinical pathways. In this review, we provide a comprehensive overview of the current research related to AI in BC, highlighting its extensive applications throughout the whole BC cycle management and its potential for innovative impact. Furthermore, this article emphasizes the significance of constructing patient-oriented AI algorithms. Additionally, we explore the opportunities and potential research directions within this burgeoning field.

ZNF703 promotes Triple-Negative breast cancer cell progression and in combination with STK11 predicts disease recurrence (ZS -TNBC Model)

BACKGROUND

It is largely unidentified concerning the underlying genetic causes responsible for triple-negative breast cancers (TNBC), with unpredictable disease recurrence. This study aimed to examine the role of ZNF703 (Zinc finger 703) in the malignant behaviors of TNBC and its role in predicting disease-free survival (DFS).

METHODS

After downregulation of ZNF703 with short interfering RNA (siRNA), we examined the proliferation of TNBC cell line MDA-MB-231 by sulforhodamine B (SRB) assay, the invasion of cells by a transwell invasion model, and the migration of cells by the monolayer wound-healing experiment. mRNA-sequencing data of ZNF703, BRCA1, BRCA2, PALB2, CHEK2, CDH1, PTEN, STK11, ATM, and TP53, and corresponding clinical information were obtained from The Cancer Genome Atlas (TCGA) dataset for a total of 157 stage I-III TNBC samples. The selection of modeling features was executed using the Least Absolute Shrinkage and Selection Operator (LASSO) regression algorithm to avoid model overfitting. The TIMER 2.0 algorithm determined the associations between immune score and gene expressions. Kaplan-Meier analysis was conducted to plot survival analyses.

RESULTS

The aggressive tumor morphology, cell proliferation, cell migration, and cell invasion were partly reversed by the siRNA knockdown of ZNF703 in MDA-MB-231 cells. ZNF703 knockdown markedly enhanced the killing ability of cisplatin These phenomena were verified by another TNBC cell line BT-549. Patients with high expression of ZNF703 had an inferior DFS for TNBC patients at 8 years [Hazard ratio (HR) for high expression vs. low expression was 2.71; 95 %CI, 1.03 to 7.14, P = 0.044]. Receiver Operating Characteristic (ROC) curve was also developed, indicating the area under the curve (AUC) was 0.744 (95 %CI, 0.628 to 0.861) at 5 years and 0.738 (95 %CI, 0.552 to 0.924) at 8 years, respectively. In addition, LASSO regression results showed that the optimal penalization parameter corresponds to two prognostic genes - ZNF703 and STK11. The risk score was computed as Risk Score (RS) = 0.1033*ZNF703 + 0.2131*STK11 (named "ZS -TNBC model"). The high expression of both ZNF703 and STK11 had as high as 7.035 HR in comparison to the low-expression category (95 %CI, 2.044 to 24.206, P = 0.00197).

CONCLUSION

ZNF703 is required for the growth, invasion, and migratory behavior of TNBC cells. Downregulation of ZNF703 increases cisplatin efficacy. This study suggests that either ZNF703 alone or in conjunction with STK11 can be utilized to predict DFS in TNBC.

Structural and Functional Insights into Targeting GCCG Sites in the EGFR Promoter by Two DNA Intercalators to Inhibit Breast Cancer Metastasis

Chemotherapeutic drugs are commonly used to treat cancers lacking targeted therapy options. However, their low specificity limits their treatment effectiveness. We report here that the cooperative binding of doxorubicin (Dox) with actinomycin D (ActD) enhances the specificity for consecutive GCCG sites in DNA. Using X-ray crystallography, we determined the crystal structure of ActD and Dox bound to d(AGCCGT)2 DNA. ActD intercalation at the GpC site induces a novel Dox binding mode at the adjacent CpG step. This ensures a snug fit, avoids steric clashes, and enhances the specificity. Transcriptome analysis revealed that combining Dox with ActD synergistically down-regulates EGFR in TNBC cells. Additionally, it reduces EGFR promoter activity. In vivo, the combination significantly suppresses tumor growth and outperforms the standard Dox and cyclophosphamide regimen in inhibiting metastasis. This study highlights targeting the activated EGFR pathway with sequence-specific DNA-targeting drug combinations as a potential TNBC treatment.

Application of a CYP1B1-Targeted NIR Probe for Breast Cancer Diagnosis, Surgical Navigation, and CYP1B1-Associated Chemotherapy Resistance Monitoring

Early detection and precise treatment for breast cancer are crucial, given its high global incidence rate. Hence, the development of novel imaging targets is essential for diagnosing and monitoring resistance to chemotherapy, which is pivotal for achieving precise and personalized treatment for breast cancer patients. In our previous work, we successfully developed a near-infrared (NIR) probe 1 for CYP1B1-targeted imaging. In this study, we aimed to investigate the utility of the probe as a NIR fluorescence and photoacoustic dual-mode imaging probe for the detection and surveillance of breast cancer. Western blotting of cancer cell lines has confirmed that CYP1B1 is widely expressed in breast cancer and gynecological cancer. In vitro NIR fluorescence imaging capability of the probe for tracking CYP1B1-positive tumor cells was validated by using confocal microscopy. Further studies, including in vivo fluorescence and photoacoustic dual-model imaging and ex vivo biological distribution analysis on a triple-negative breast cancer xenograft mouse model, demonstrated that the probe selectively accumulated in tumor tissue within as early as 0.5 h postinjection. The results of the surgical resection experiment revealed that the tumor could be entirely removed under the guidance of NIR imaging, thereby indicating the probe's efficacy in surgical navigation. CYP1B1 expression was found to be upregulated in adriamycin (ADR)-resistant breast cancer cells, MCF-7/ADR. Consequently, the sensitivity of CYP1B1 overexpressed cells, MCF-7/1B1, to ADR was significantly reduced, with an IC50 value of 0.586 ± 0.0934 μM, compared to the parental MCF-7 cells with an IC50 value of 0.183 ± 0.0444 μM. In vivo and ex vivo imaging assays conducted on MCF-7/ADR tumor-bearing mice demonstrated that the probe was specifically enriched in tumor sites, suggesting its potential for monitoring chemotherapy resistance in breast cancer. This study expands the scope of application for NIR probe 1, establishing its utility in breast cancer diagnosis through fluorescence-photoacoustic dual-model imaging, monitoring of chemotherapy resistance, and guidance for surgical resection. This strategy paves the way for novel approaches to precise and personalized treatment for breast cancer patients.

Pilot Study of Nectin-4-Targeted PET Imaging Agent 68Ga-FZ-NR-1 in Triple-Negative Breast Cancer from Bench to First-in-Human

Nectin cell adhesion molecule 4 (Nectin-4) is an emerging biomarker for cancer diagnosis and therapy. We developed a Nectin-4-targeted 68Ga-DOTA-Sar10-Nectin-4 (68Ga-FZ-NR-1) PET/CT radiotracer for detecting Nectin-4 expression in a tumor model and in triple-negative breast cancer (TNBC) patients. Methods: A series of Nectin-4-targeted radiotracers-68Ga-FZ-NR-1, 68Ga-DOTA-polyethylene glycol 5-Nectin-4 (68Ga-FZ-NR-2), and 68Ga-DOTA-polyethylene glycol 10-Nectin-4 (68Ga-FZ-NR-3)-were synthesized, and their targeting ability and specificity were evaluated in vitro and in vivo. In vitro experiments were performed in the MDA-MB-468 (Nectin-4-positive) and MDA-MB-231 (Nectin-4-negative) cell lines. PET/CT imaging in tumor models was performed to assess the Nectin-4-targeting ability of the radiotracers. After preclinical experiments and screening, the 68Ga-FZ-NR-1 radiotracer was selected for safety and efficacy evaluation in a first-in-human trial in TNBC patients. Positive lesions were biopsied and analyzed by immunohistochemistry to determine Nectin-4 expression levels. Results: The 3 68Ga-labeled radiotracers exhibited high radiochemical purity, stability, and strong affinity for Nectin-4. In vitro cell uptake studies showed that the radiotracers effectively targeted Nectin-4 in MDA-MB-468 cells, and 68Ga-FZ-NR-1 showed the highest targeting efficacy. In the MDA-MB-468 tumor model, PET/CT imaging showed that 68Ga-FZ-NR-1 was taken up at higher rates than 68Ga-FZ-NR-2 and 68Ga-FZ-NR-3, and it exhibited favorable pharmacokinetics and safety profiles. 68Ga-FZ-NR-1 was thus selected for subsequent clinical trials. 68Ga-FZ-NR-1 PET/CT effectively identified tumors in 9 patients with TNBC, which was confirmed by 18F-FDG PET/CT. Biopsy samples of the tumor lesions revealed that the positive lesions identified by 68Ga-FZ-NR-1 PET/CT corresponded to areas of high Nectin-4 expression. Conclusion: A series of Nectin-4-targeted radiotracers (68Ga-FZ-NR-1, 68Ga-FZ-NR-2, and 68Ga-FZ-NR-3) was developed and evaluated. Preclinical studies demonstrated that 68Ga-FZ-NR-1 can identify tumors with high Nectin-4 expression. In a preliminary clinical study, 68Ga-FZ-NR-1 was used to effectively identify and visualize Nectin-4-expressing tumor lesions in patients with TNBC, which was confirmed by immunohistochemistry. This radiotracer provides a noninvasive approach to the assessment of Nectin-4 and a potential basis for the development of Nectin-4-targeted treatments for TNBC.

Accumulation of CD38 in Hybrid Epithelial/Mesenchymal Cells Promotes Immune Remodeling and Metastasis in Breast Cancer

Triple-negative breast cancer (TNBC) is a highly metastatic subtype of breast cancer. The epithelial-to-mesenchymal transition is a nonbinary process in the metastatic cascade that generates tumor cells with both epithelial and mesenchymal traits known as hybrid EM cells. Recent studies have elucidated the enhanced metastatic potential of cancers featuring the hybrid EM phenotype, highlighting the need to uncover molecular drivers and targetable vulnerabilities of the hybrid EM state. Here, we discovered that hybrid EM breast tumors are enriched in CD38, an immunosuppressive molecule associated with worse clinical outcomes in liquid malignancies. Altering CD38 expression in tumor cell impacted migratory, invasive, and metastatic capabilities of hybrid EM cells. Abrogation of CD38 expression stimulated an antitumor immune response, thereby preventing the generation of an immunosuppressive microenvironment in hybrid EM tumors. CD38 levels positively correlated with PD-L1 expression in samples from patients with TNBC. Moreover, targeting CD38 potentiated the activity of anti-PD-L1, eliciting strong antitumor immunity, with reduced tumor growth in hybrid EM models. Overall, this research exposes upregulation of CD38 as a specific survival strategy utilized by hybrid EM breast tumors to suppress immune cell activity and sustain metastasis, with strong implications in other carcinomas that have hybrid EM properties. Significance: Hybrid cells co-featuring epithelial and mesenchymal traits in triple-negative breast cancer express elevated levels of CD38 to induce immunosuppression and metastasis, indicating CD38 inhibition as potential strategy for treating breast cancer.

Facile integration of a binary nano-prodrug with αPD-L1 as a translatable technology for potent immunotherapy of TNBC

Immune checkpoint blockers (ICBs)-based immunotherapy is a favorable approach for efficient triple-negative breast cancer (TNBC) treatment. However, the therapeutic efficacy of ICBs is greatly compromised by immunosuppressive tumor microenvironments (TMEs) and low expression levels of programmed cell death ligand-1 (PD-L1). Herein, we constructed an amphiphilic prodrug by linking a hydrophobic STING agonist, MSA-2 and a hydrophilic chemotherapeutic drug, gemcitabine (GEM) via an ester bond, which can self-assemble into GEM-MSA-2 (G-M) nanoparticles (NPs) with a tumor growth inhibition (TGI) value of 87.1 % in a murine 4T1 transplantation tumor model. Notably, the immunogenic cell death (ICD)-triggering effect of GEM together with the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway activation properties of MSA-2 enables efficient infiltration of non-exhausting T cells and repolarization of macrophages from M2 to M1 types in the tumor microenvironment for transforming a cold tumor to a hot one. Most importantly, G-M NPs treatment increases the PD-L1 expression levels, thus providing a unique opportunity for further integration with anti-PD-L1 monoclonal antibody (αPD-L1) for eliciting stronger immunity that ultimately leads to a TGI value of 98.0 % in the primary tumor and significantly protects against distal and disseminated tumor rechallenge. Overall, this study presents a minimalist nano-prodrug combined with αPD-L1 as a simple yet robust translatable nanotechnology for potent chemo-immunotherapy of TNBC. STATEMENT OF SIGNIFICANCE: Enhancing the therapeutic efficacy of αPD-L1 for tumor immunotherapy via a translatable technology remains a challenge. We report herein facile integration of a binary nano-prodrug with αPD-L1 for potent immunotherapy of TNBC. An amphiphilic prodrug is constructed by linking a hydrophobic STING agonist, MSA-2 and a hydrophilic chemotherapeutic drug, gemcitabine (GEM) via an ester bond. The resulting self-assembled GEM-MSA-2 (G-M) nanoparticles (NPs) show a tumor growth inhibition (TGI) value of 87.1 % in a murine 4T1 transplantation tumor model. Besides the induced immunogenic cell death (ICD) and activated cGAS-STING pathway, G-M NPs increase the PD-L1 expression levels, providing a unique opportunity for further integration with αPD-L1 to elicit stronger immunity that ultimately leads to a TGI value of 98.0 % in the primary tumor and significantly protects against distal and disseminated tumor rechallenge.

Synergistic effects of thermosensitive liposomal doxorubicin, mild hyperthermia, and radiotherapy in breast cancer management: an orthotopic mouse model study

Liposome formulations of the cancer drug doxorubicin have been developed to address the severe side effects that result from administration of this drug in a conventional formulation. Among them, thermosensitive liposomal doxorubicin presents enhanced tumor targeting and efficient drug release when combined with mild hyperthermia localized to the tumor site. Exploiting the radiosensitizing benefits of localized thermal therapy, the integration of radiation therapy with the thermally activated liposomal system is posited to amplify the anti-tumor efficacy. This study explored a synergistic therapeutic strategy that combines thermosensitive liposomal doxorubicin, mild hyperthermia, and radiotherapy, using an orthotopic murine model of breast cancer. The protocol of sequential multi-modal treatment, incorporating low-dose chemotherapy and radiotherapy, substantially postponed the progression of primary tumor growth in comparison to the application of monotherapy at elevated dosages. Improvements in unheated distant lesions were also observed. Furthermore, the toxicity associated with the combination treatment was comparable to that of either thermosensitive liposome treatment or radiation alone at low doses. These outcomes underscore the potential of multi-modal therapeutic strategies to refine treatment efficacy while concurrently diminishing adverse effects in the management of breast cancer, providing valuable insight for the future refinement of thermosensitive liposomal doxorubicin applications.

Breast cancer stem cell-derived exosomal lnc-PDGFD induces fibroblast-niche formation and promotes lung metastasis

Triple-negative breast cancer (TNBC) is the most aggressive subtype with high metastatic potential and lack of therapeutic targets. Breast cancer stem cells (BCSCs) are enriched in TNBC and contribute to its metastatic propensity. Accumulating evidence suggests that cancer-derived exosomes are key drivers of premetastatic niche formation in distal organs. However, the function and underlying mechanism of BCSC-derived exosomes in TNBC metastasis remain elusive. Here, we demonstrated that BCSC-derived exosomes exhibit a greater capacity to activate fibroblasts and promote TNBC cell metastasis to the lung than non-BCSC-derived exosomes. Additionally, we found that upregulation of exosomal long non-coding RNA platelet derived growth factor D (lnc-PDGFD) expression in BCSCs is responsible for fibroblast activation through YBX1/NF-kB signaling in the lung. Activated fibroblasts further promote tumor progression by secreting IL-11. Taken together, BCSC-derived exosomes enriched with lnc-PDGFD could activate fibroblasts, thereby facilitating lung metastasis in TNBC patients. These results provide new insights into the mechanism of TNBC metastasis to the lung.

An update on cancer stem cell survival pathways involved in chemoresistance in triple-negative breast cancer

Triple-negative breast cancer (TNBC) presents a formidable global health challenge, marked by its aggressive behavior and significant treatment resistance. This subtype, devoid of estrogen, progesterone, and HER2 receptors, largely relies on breast cancer stem cells (BCSCs) for its progression, metastasis, and recurrence. BCSCs, characterized by their self-renewal capacity and resistance to conventional therapies, exploit key surface markers and critical signaling pathways like Wnt, Hedgehog, Notch, TGF-β, PI3K/AKT/mTOR and Hippo-YAP/TAZ to thrive. Their adaptability is underscored by mechanisms including drug efflux and enhanced DNA repair, contributing to poor prognosis and high recurrence rates. The tumor microenvironment (TME) further facilitates BCSC survival through complex interactions with stromal and immune cells. Emerging therapeutic strategies targeting BCSCs - ranging from immunotherapy and nanoparticle-based drug delivery systems to gene-editing technologies - aim to disrupt these resistant cells. Additionally, innovative approaches focusing on exosome-mediated signaling and metabolic reprogramming show promise in overcoming chemoresistance. By elucidating the distinct characteristics of BCSCs and their role in TNBC, researchers are paving the way for novel treatments that may effectively eradicate these resilient cells, mitigate metastasis, and ultimately improve patient outcomes. This review highlights the urgent need for targeted strategies that address the unique biology of BCSCs in the pursuit of more effective therapeutic interventions for TNBC.

Unveiling the role of MDH1 in breast cancer drug resistance through single-cell sequencing and schottenol intervention

This study utilizes single-cell RNA sequencing data to reveal the transcriptomic characteristics of breast cancer and normal epithelial cells. Nine significant cell populations were identified through stringent quality control and batch effect correction. Further classification of breast cancer epithelial cells based on the PAM50 method and clinical subtypes highlighted significant heterogeneity between triple-negative breast cancer (TNBC) and non-triple-negative breast cancer (NTNBC). The study also analyzed myeloid cells and tumor-infiltrating lymphocytes (TILs) within the breast cancer immune microenvironment, identifying 14 TIL subpopulations and assessing their proportion variations across different patients. The CellChat tool revealed a complex cellular communication network within the tumor microenvironment, showing notable differences in communication intensity and patterns between TNBC and NTNBC patients. Additionally, the key regulatory role of the senescence-associated gene MDH1 in breast cancer was confirmed, and its impact on drug sensitivity was explored. Finally, it was discovered that the phytosterol Schottenol inhibits breast cancer cell proliferation by downregulating MDH1 expression and enhances sensitivity to paclitaxel. These findings provide new insights into MDH1 as a therapeutic target and suggest Schottenol as a potential strategy to overcome breast cancer drug resistance.

The emerging landscape of small nucleolar RNA host gene 10 in cancer mechanistic insights and clinical relevance

Small nucleolar RNA host gene 10 (SNHG10) is a newly recognized long non-coding RNA (lncRNA) with significant implications in cancer biology. Abnormal expression of SNHG10 has been observed in various solid tumors and hematological malignancies. Research conducted in vivo and in vitro has revealed that SNHG10 plays a pivotal role in numerous biological processes, including cell proliferation, apoptosis, invasion and migration, drug resistance, energy metabolism, immune evasion, as well as tumor growth and metastasis. SNHG10 regulates tumor development through several mechanisms, such as competing with microRNA (miRNA) for binding sites, modulating various signaling pathways, influencing transcriptional activity, and affecting epigenetic regulation. The diverse biological functions and intricate mechanisms of SNHG10 highlight its considerable clinical relevance, positioning it as a potential pan-cancer biomarker and therapeutic target. This review aims to summarize the role of SNHG10 in tumorigenesis and cancer progression, clarify the molecular mechanisms at play, and explore its clinical significance in cancer diagnosis and prognosis prediction, along with its therapeutic potential.

Design, synthesis and optimization of Apcin analogues as Cdc20 inhibitors for triple-negative breast cancer therapy

Cell division cycle 20 homologue (Cdc20) is an essential mitotic regulator whose overexpression is closely associated with tumorigenesis and poor prognosis in triple-negative breast cancer (TNBC). Targeting Cdc20 has therefore emerged as a promising therapeutic avenue for this aggressive malignancy. In the present study, a receptor-based drug design approach was employed to optimize Apcin analogues as Cdc20 inhibitors. Through a two-step strategy-concept validation followed by structural optimization-we identified compound 14c, which demonstrated remarkable Cdc20 binding affinity (KD: 7.65 μM), potent antiproliferative effects against MDA-MB-231 TNBC cells (IC50: 3.28 μM), and a favorable selectivity index (4.22 for MCF-7 non-TNBC cells and 7.27 for MCF 10A normal cells). 14c effectively inhibited Cdc20 activity, induced G2/M phase arrest, promoted DNA damage accumulation, and stabilized key substrates such as Cyclin B1 and Bim, leading to enhanced apoptosis and suppression of tumor cell proliferation and migration. In vivo, 14c significantly inhibited tumor growth in an MDA-MB-231 xenograft model with a 90 % tumor inhibition rate and no observable toxicity. These results highlight the potential of 14c as a potent Cdc20 inhibitor, offering a promising therapeutic approach for TNBC.

Organ-targeted drug delivery systems (OTDDS) of poly[(N-acryloylglycine)-co-(N-acryloyl-L-phenylalanine methyl ester)] copolymer library and effective treatment of triple-negative breast cancer

Organ-targeted drug delivery systems (OTDDS) are essential for the effective treatment of complicated diseases. Triple-negative breast cancer (TNBC) is an aggressive cancer with high mortality and requires targeted therapeutics. This work was aimed at designing a library of polymeric OTDDS with N-acryloyl-glycine (NAG) and N-acryloyl-L-phenylalanine methyl ester (NAPA) [p(NAG-co-NAPA)(x:y)] and screening its in vivo organ-targeting specificity. Among this library, the best p(NAG-co-NAPA)(x:y) NPs with an x : y ratio of 1 : 4 and size of 160-210 nm targeted breasts to a high extent compared to other organs and thus were optimized for TNBC treatment. A network pharmacology study was performed, which revealed that 14 genes were responsible for TNBC, and a combination of DHA (targets 6 genes) and piperine (targets 8 genes) drugs was used to optimize the formulation, achieving the maximum therapeutic efficiency against TNBC with an IC50 value of 350 μg mL-1. The designed organ-specific polymeric nanoparticle (NP) library, identification of target genes and proteins responsible for TNBC, and the optimized formulation for effective combination therapy established an effective therapeutic option for TNBC. The findings of this work further demonstrate that this polymeric library of NPs shows exciting therapeutic potential for treating TNBC and presents innovative treatment options for critical diseases of the liver, heart, lungs and kidney.

Camrelizumab vs Placebo in Combination With Chemotherapy as Neoadjuvant Treatment in Patients With Early or Locally Advanced Triple-Negative Breast Cancer: The CamRelief Randomized Clinical Trial

Importance

Preferred neoadjuvant strategies for early or locally advanced triple-negative breast cancer include a 4-drug chemotherapy regimen containing anthracyclines, cyclophosphamide, taxanes, and platinum. Blockade of the programmed death receptor 1/ligand-1 (PD-1/PD-L1) pathway may improve efficacy of classic neoadjuvant chemotherapy. Camrelizumab, an anti-PD-1 antibody, has showed antitumor activity in advanced triple-negative breast cancer.

Objective

To evaluate the efficacy and adverse events of camrelizumab plus chemotherapy vs placebo plus chemotherapy as neoadjuvant therapy for patients with early or locally advanced triple-negative breast cancer.

Design, Setting, and Participants

This randomized, double-blind, phase 3 trial enrolled patients from 40 hospitals in China between November 25, 2020, and May 12, 2023 (data cutoff: September 30, 2023). A total of 441 eligible patients were enrolled.

Interventions

Patients were randomized in a 1:1 ratio to receive either camrelizumab 200 mg (n = 222) or placebo (n = 219) combined with chemotherapy every 2 weeks. The chemotherapy included nab-paclitaxel (100 mg/m2) and carboplatin (area under the curve, 1.5) on days 1, 8, and 15 in 28-day cycles for the first 16 weeks followed by epirubicin (90 mg/m2) and cyclophosphamide (500 mg/m2) every 2 weeks for 8 weeks.

Main Outcomes and Measures

The primary end point was pathological complete response (defined as no invasive tumor in breast and lymph nodes [ypT0/Tis ypN0]).

Results

Among 441 females randomized (median age, 48 years), the median (range) follow-up duration from randomization was 14.4 (0.0-31.8) months. Pathological complete response was achieved in 126 patients (56.8% [95% CI, 50.0%-63.4%]) in the camrelizumab-chemotherapy group and 98 patients (44.7% [95% CI, 38.0%-51.6%]) in the placebo-chemotherapy group (rate difference, 12.2% [95% CI, 3.3%-21.2%]; 1-sided P = .004). In the neoadjuvant phase, adverse events of grade 3 or higher occurred in 198 patients (89.2%) in the camrelizumab-chemotherapy group and 182 (83.1%) in the placebo-chemotherapy group; serious adverse events occurred in 77 patients (34.7%) in the camrelizumab-chemotherapy group and 50 (22.8%) in the placebo-chemotherapy group, with fatal adverse events occurring in 2 patients (0.9%) in the camrelizumab-chemotherapy group.

Conclusions and Relevance

Among patients with early or locally advanced triple-negative breast cancer, the addition of camrelizumab to neoadjuvant chemotherapy significantly improved pathological complete response.

Trial Registration

ClinicalTrials.gov Identifier: NCT04613674.

Dual inhibitor of MDM2 and NFAT1 for experimental therapy of breast cancer: in vitro and in vivo anticancer activities and newly discovered effects on cancer metabolic pathways

Introduction

The oncogene MDM2 has garnered attention not only for its role in cancer as a negative regulator of the tumor suppressor p53 but also for its p53-independent oncogenic activities. MDM2 also involves metabolic reprogramming, such as serine metabolism, respiration, mitochondrial functions, the folate cycle, and redox balance. Traditional MDM2 inhibitors blocking the protein-protein binding between MDM2 and p53 have shown limited clinical success in various stages of clinical trials, most likely due to low efficacy, drug toxicity, and drug resistance, highlighting the need for a novel, p53-independent strategy to inhibit MDM2. The present study investigated the antitumor effects of MA242, a novel MDM2 and NFAT1 inhibitor, in breast cancer models.

Methods

The anticancer activity and underlying mechanisms of MA242 were evaluated in vitro using breast cancer cell lines with different p53 backgrounds and in vivo using orthotopic and patient-derived xenograft models.

Results

We demonstrated that MA242 significantly inhibited cell viability and induced apoptosis in breast cancer cells, regardless of p53 status. Metabolic analysis revealed that MA242 notably disrupted nicotinamide metabolism, modified nucleotide metabolism, and elevated cellular oxidative stress by disturbing the redox balance. Furthermore, in animal models, MA242 reduced MDM2 expression and effectively inhibited tumor growth dependent on MDM2 expression without causing host toxicity.

Discussion

These findings highlight the potential of MA242 as a modulator of cancer metabolism and support its further development as a therapeutic option for aggressive breast cancers.

Whole-Component Antigen Nanovaccines Combined With aTIGIT for Enhanced Innate and Adaptive Anti-tumor Immunity

Using entire tumor cells or tissues that display both common and patient-specific antigens can potentially trigger a comprehensive and long-lasting anti-tumor immune response. However, the limited immunogenicity, low uptake efficiency, and susceptibility to degradation of whole-component antigens present significant challenges. In this study, we employed tumor lysates (TLs) as whole-component antigens, in conjunction with MgAl-layered double hydroxide (MA) as nanoadjuvants and Mn2+ as immunostimulants, to create personalized MMAT (Mn2+-MA-TLs) nanovaccines. After subcutaneous injection of MMAT nanovaccines, the high local concentrations of TLs and Mn2+ facilitated the recruitment and activation of antigen-presenting cells (APCs), thereby inducing a robust adaptive immune response. Remarkably, MMAT nanovaccines enabled lysosomal escape, enhanced antigen cross-presentation, and activated the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway in APCs. Furthermore, MMAT nanovaccines, when combined with the anti-TIGIT monoclonal antibody (aTIGIT), an immune checkpoint inhibitor, not only stimulated T-cell-based adaptive anti-tumor immune responses but also activated the NK-cell-based innate anti-tumor immunity, effectively suppressing tumor growth, recurrence, and metastasis. Thus, the ternary MMAT nanovaccines developed here introduced a pioneered paradigm for the rapid preparation of whole-component tumor antigens with nanoadjuvants and immunostimulants into nanovaccines, offering new prospects for clinical immunotherapies.

Cryo-Shocked Tumor-Reprogrammed Sonosensitive Antigen-Presenting Cells Improving Sonoimmunotherapy via T Cells and NK Cells Immunity

Ultrasound therapy has turned up as a noninvasive multifunctional tool for cancer immunotherapy. However, the insufficient co-stimulating molecules and loss of peptide-major histocompatibility complex I (MHC-I) expression on tumor cells lead to poor therapy of sonoimmunotherapies. Herein, this work develops a sonosensitive system to augment MHC-I unrestricted natural killer (NK) cell-mediated innate immunity and T cell-mediated adaptive immunity by leveraging antigen presentation cell (APC)-like tumor cells. Genetically engineered tumor cells featuring sufficient co-stimulating molecules are cryo-shocked and conjugated with a sonosensitizer, hematoporphyrin monomethyl ether, using click chemistry. These cells (DPNLs) exhibit characteristics of tumor and draining lymph node homing. Under ultrasound, NK cell-mediated innate immunity within the tumor microenvironment could be activated, and T cells in the tumor-draining lymph nodes (TDLNs) are stimulated through co-stimulatory molecules. In combination with programmed cell death ligand 1 (PD-L1) antibody, DPNLs extend the survival time and inhibited lung metastasis in triple-negative breast cancer (TNBC) models. This study provides an alternative approach for sonoimmunotherapy with precise sonosensitizer delivery and enhanced NK cell and T cell activation.

Triple-Negative Breast Cancer Systemic Treatment: Disruptive Early-Stage Developments for Overcoming Stagnation in the Advanced Pipeline

New breast cancer (BC) diagnoses will soon reach 2.5-3 million/year worldwide, with 15-25% of them being triple-negative breast cancer (TNBC), the most aggressive type, characterized for lacking the main pharmacological targets: estrogen and progesterone receptors (ERs and PRs), as well as HER2 overexpression. Therefore, chemotherapy remains the almost-unique systemic treatment for TNBC. However, some targeted therapies are recommended for use in combination with chemotherapy; namely, PARP inhibitors for BRCA-mutated TNBC, the immune checkpoint inhibitors pembrolizumab and atezolizumab, as well as the antibody-drug conjugates sacituzumab govitecan and trastuzumab deruxtecan, the latter for HER2low subtypes. Regardless of the limited benefits they provide, other treatments with similar mechanisms of action are being investigated in advanced clinical stages. Further, therapies that benefit other cancers, like PI3K/Akt/mTOR pathway and CDK4/6 inhibitors, are still being investigated for TNBC, although convincing results have not been obtained. Given this scenario, it might appear innovation for TNBC treatments has become stuck. However, the huge unmet medical need drives intense research into the biology of the disease. As a result, emerging disruptive therapies are being tested in early-stage trials, designed for novel targets and applying cutting-edge advances in immunotherapy and precision oncology.

A randomized phase II trial of nab-paclitaxel with or without mifepristone for advanced triple-negative breast cancer

PURPOSE

Glucocorticoid receptor (GR) activity may mediate chemoresistance in advanced triple-negative breast cancer (TNBC). Preclinical studies demonstrate that GR antagonism can augment the effect of taxanes in TNBC models. We hypothesized that pretreatment with mifepristone, a potent GR antagonist, would enhance nab-paclitaxel efficacy in advanced TNBC.

METHODS

This trial was terminated early due to poor accrual. 29 of 64 planned patients were enrolled. Patients were randomized to receive nab-paclitaxel with or without mifepristone; oral mifepristone 300 mg was administered the day prior and day of each dose of nab-paclitaxel. The primary endpoint was progression-free survival (PFS); secondary/exploratory endpoints included response rate and correlation of response with GR expression.

RESULTS

The addition of mifepristone to nab-paclitaxel did not improve PFS (3.0 m vs 3.0 m, p = 0.687) or overall response rate (23% vs 31.5%) compared to nab-paclitaxel alone. There was a trend towards improved overall survival in the combination group, primarily driven by one long-term responder. Increased rates of grade 3 neutropenia (46% vs 7%) and febrile neutropenia were observed in the combination arm, while other toxicities were similar in both groups. Increased GR expression was not correlated with clinical response in the combination arm.

CONCLUSIONS

While there were responders to the combination, the study was underpowered to meet the primary endpoint. Higher rates of neutropenia were observed in the combination, but overall it was well tolerated. Preclinical data in TNBC and clinical data in other malignancies support further investigation of GR modulators. Future studies should incorporate biomarkers to select patients who benefit from GR inhibition.

Continuous replenishment of the dysfunctional CD8 T cell axis is associated with response to chemoimmunotherapy in advanced breast cancer

Chemotherapy combined with immune checkpoint blockade has shown clinical activity in breast cancer. Response, however, occurs in only a low proportion of patients. How the immune landscape of the tumor determines the immune and clinical responses to chemoimmunotherapy is not well understood. Here, using a combination of single-cell RNA sequencing (scRNA-seq) and single-cell T cell receptor sequencing (scTCR-seq), we profile 40 biopsies from 27 patients with metastatic triple-negative breast cancer (TNBC), receiving chemotherapy and anti-PD-L1 alone or in combination with anti-CD73, in a phase 2 randomized clinical trial. Our results show an enrichment of late-dysfunctional, clonally expanded CD8+ T cells in responder (R) patients. On treatment, R display an influx of newly emerging clonotypes, as well as expansion of the CD8+ precursors. Collectively, our data suggest that baseline clonal expansion could be a potential predictor of response and that both clonal reinvigoration of pre-existing tumor-reactive T cells and clonal replacement on-treatment are important for a protective response to chemoimmunotherapy.

UBE2T/CDC42/CD276 signaling axis mediates brain metastasis of triple-negative breast cancer via lysosomal autophagy

BACKGROUND

Advanced triple-negative breast cancer (TNBC) is prone to brain metastasis (BrM). The precise molecular mechanism responsible for this phenomenon has not yet been completely established, so it is vital to comprehend the molecular mechanism behind it.

METHODS

The protein chip analysis was conducted to identify any abnormal UBE2T protein expression in TNBC, especially BrM. Here, we used public databases and bioinformatics analysis as well as clinical samples from different cohorts to investigate the interrelationship between UBE2T/CDC42/CD276. This predicted relationship was then repeatedly validated using different in vivo and in vitro experimental methods. Additionally, multiple experimental approaches were implemented, encompassing western blotting, Co-IP, GST pull-down, flow cytometry, mass spectrometry, immunofluorescence, immunohistochemistry, and qRT-PCR to reveal the molecular mechanism of UBE2T-mediated immune escape and BrM.

RESULTS

Our results indicate that expressed at elevated levels in breast cancer, UBE2T is negatively linked to patient prognosis, especially in BrM of TNBC. Data from clinical samples from our different cohorts and TCGA indicate a significant correlation between UBE2T and immunosuppression. Mechanistically, UBE2T directly interacts with CDC42, promoting its K48-linked polyubiquitination and proteasomal degradation, thereby inhibiting CDC42 from degrading CD276 via the autophagy-lysosomal pathway, indirectly upregulating CD276 and thereby impairing the CD8+ T cells function, ultimately mediating tumor immune escape and BrM. Finally, animal experimental results also showed that inhibition of UBE2T elevated the TNBC sensitivity to immune checkpoint CD276 blockade and inhibited BrM of TNBC.

CONCLUSIONS

In conclusion, our results indicate a new mechanism whereby UBE2T-mediated ubiquitination positively controls the UBE2T/CDC42/CD276 axis to upregulate tumor cell expression of CD276 and thereby impair CD8+ T cells function, ultimately leading to tumor cell immune escape and BrM.

Programmed Cell Death Ligand 1 (PD-L1) and Major Histocompatibility Complex Class I (MHC Class I) Expression Patterns and Their Pathologic Associations in Triple-Negative Breast Cancer

Purpose

This study aims to investigate the clinicopathological characteristics of triple-negative breast cancer (TNBC) in relation to programmed cell death ligand 1 (PD-L1) and major histocompatibility complex class I (MHC class I) expression, with a focus on their prognostic significance.

Patients and Methods

A retrospective analysis was conducted on formalin-fixed paraffin-embedded (FFPE) tissue samples from 148 TNBC patients diagnosed between 2008 and 2021. Immunohistochemical analysis evaluated PD-L1 and MHC class I expression. PD-L1 was assessed using Combine Positive Scores (CPS), with the threshold set at CPS ≥ 1 and CPS ≥ 10. MHC class I expression was categorized into low and high levels. Associations between these markers, clinicopathological features, overall survival (OS), and disease-free survival (DFS) were analyzed. PD-L1 expression was also compared between older FFPE blocks (2008-2018) versus newer blocks (2019-2021).

Results

PD-L1 expression was observed in 29.1% of cases with a Combined Positive Score (CPS) ≥1 and 8.8% of CPS ≥10 cases. MHC class I expression was evenly split between low and high levels. Older FFPE blocks (2008-2018) showed lower PD-L1 expression than newer blocks (2019-2021). There was no significant association between PD-L1 expression and overall survival (OS) or disease-free survival (DFS). However, high MHC class I expression was strongly associated with improved OS (HR = 0.469, 95% CI: 0.282-0.780, p=0.004). Patients with negative PD-L1 and high MHC class I expression had the most favorable prognosis, with significant OS for CPS ≥1 (HR = 0.447, 95% CI: 0.236-0.846, p=0.013) and CPS ≥10 (HR = 0.516, 95% CI: 0.307-0.869, p=0.013).

Conclusion

These findings support the potential of PD-L1 and MHC class I expression as prognostic markers for TNBC, offering insights to guide treatment decisions and improve patient outcomes.

Chemical probes for the identification of the molecular targets of honokiol

Honokiol is a natural product with an interesting array of biological effects, including significant anti-tumor properties. However, full exploration of its therapeutic potential is hampered by its modest pharmacokinetic profile and by the lack of synthetic methods that allow to obtain specifically designed derivatives with improved properties. In addition, the specific molecular targets of honokiol remain poorly understood, a fact that limits the search of alternative hits for subsequent optimization programs. In this work we describe an optimized series of synthetic routes that allow to access to a variety of honokiol derivatives, including a set of minimalist photoaffinity probes to map potential protein targets in live cells. Chemical proteomic studies of the most potent probe revealed a defined set of proteins as the cellular targets of honokiol. Significantly, up to the 62 % of the identified proteins have described roles in cancer, highlighting their potential relationship with the antitumor effects of honokiol. Furthermore, several of the top hits have been validated as direct binding partners of honokiol by cellular thermal shift assay (CETSA). In sum, the work described herein provides the first landscape of the cellular targets of honokiol in living cells and contributes to define the specific molecular pathways affected by this natural product.

Class-aware multi-level attention learning for semi-supervised breast cancer diagnosis under imbalanced label distribution

Breast cancer affects a significant number of patients worldwide, and early diagnosis is critical for improving cure rates and prognosis. Deep learning-based breast cancer classification algorithms have substantially alleviated the burden on medical personnel. However, existing breast cancer diagnosis models face notable limitations which are challenging to obtain in clinical settings, such as reliance on a large volume of labeled samples, an inability to comprehensively extract features from breast cancer images, and susceptibility to overfitting on account of imbalanced class distribution. Therefore, we propose the class-aware multi-level attention learning model focused on semi-supervised breast cancer diagnosis to effectively reduce the dependency on extensive data annotation. Additionally, we develop the multi-level fusion attention learning module, which integrates multiple mutual attention components across different layers, allowing the model to precisely identify critical regions for lesion categorization. Finally, we design the class-aware adaptive pseudo-labeling module which adaptively predicts category distribution in unlabeled data, and directs the model to focus on underrepresented categories, ensuring a balanced learning process. Experimental results on the BACH dataset demonstrate that our proposed model achieves an accuracy of 86.7% with only 40% labeled microscopic data, showcasing its outstanding contribution to semi-supervised breast cancer diagnosis.

Chemoproteomics reveals proteome-wide covalent and non-covalent targets of withaferin A

Withaferin A (WA), a natural product used in traditional medicine, has recently garnered attention because of its diverse pharmacological effects. However, the direct targets responsible for these effects remain elusive. The discovery of targets is usually serendipitous and research has predominantly concentrated on covalent interactions, overlooking non-covalent targets. The unbiased and proteome-wide mapping of WA-interacting proteins in living cells remains largely unexplored. We have developed a chemical proteomics platform that enabled profiling of the covalent/non-covalent interactome and target occupancy in disease-related cells, which was used to reveal the landscape of the targets of WA in triple-negative breast cancer (TNBC) cells. Analysis of the discovered high-occupancy targets suggested that WA was substantially involved in the RNA metabolism pathway, in addition to other biological processes. Moreover, we biochemically validated a selection of previously unknown high-occupancy targets from various important biological pathways, including the non-covalent target MVK and covalent targets HNRNPF and CKAP4, which all play critical roles in TNBC. Collectively, these findings provided a target map for comprehensive understanding of the anti-TNBC activity of WA, and present WA-targetable proteins as new avenues for pharmacological intervention in TNBC. We anticipate that this platform will be applicable for the unbiased profiling of the targets of WA in various other disease-related cell models, as well as for other bioactive electrophilic natural products in different pathophysiological systems.

Neoadjuvant anti-4-1BB confers protection against spontaneous metastasis through low-affinity intratumor CD8 + T cells in triple-negative breast cancer

Neoadjuvant immunotherapy seeks to harness the primary tumor as a source of relevant tumor antigens to enhance systemic anti-tumor immunity through improved immunological surveillance. Despite having revolutionized the treatment of patients with high-risk early-stage triple-negative breast cancer (TNBC), a significant portion of patients remain unresponsive and succumb to metastatic recurrence post-treatment. Here, we found that optimally scheduled neoadjuvant administration of anti-4-1BB monotherapy was able to counteract metastases and prolong survival following surgical resection. Phenotypic and transcriptional profiling revealed enhanced 4-1BB expression on tumor-infiltrating intermediate (T int ), relative to progenitor (T prog ) and terminally exhausted (T term ) T cells. Furthermore, T int was enriched in low-affinity T cells. Treatment with anti-4-1BB drove clonal expansion of T int , with reduced expression of tissue-retention marker CD103 in T prog . This was accompanied by increased TCR clonotype sharing between paired tumors and pre-metastatic lungs. Further interrogation of sorted intratumor T cells confirmed enhanced T cell egress into circulation following anti-4-1BB treatment. In addition, gene signature extracted from anti-4-1BB treated T int was consistently associated with improved clinical outcomes in BRCA patients. Combinatorial neoadjuvant anti-4-1BB and ablation of tumor-derived CXCL16 resulted in enhanced therapeutic effect. These findings illustrate the intratumor changes underpinning the efficacy of neoadjuvant anti-4-1BB, highlighting the reciprocity between local tissue-retention and distant immunologic fortification, suggesting treatment can reverse the siphoning of intratumor T cells to primary tumor, enabling redistribution to distant tissues and subsequent protection against metastases.

FOXO4 suppresses cisplatin resistance of triple-negative breast cancer by inhibiting autophagy

BACKGROUND

Resistance to chemotherapy containing cisplatin (DDP) is a main challenge in the treatment of triple-negative breast cancer (TNBC). Forkhead box O4 (FOXO4) is frequently downregulated in DDP-resistant cells. However, it is unclear whether FOXO4 down-regulation is related to DDP resistance. Here, we investigated the relationship between FOXO4 and DDP resistance in TNBC.

METHODS

We established the DDP-resistant cell lines MDA-MB-231/DDP and BT-549/DDP through in vitro selection. CCK-8 and colony formation assays analyzed cell growth. The resistance index was calculated. Cell autophagy was evaluated. Western blotting and qRT-PCR measured protein and gene expression. The binding between FOXO4 and TGF-β1 was determined by the dual-luciferase reporter assay.

RESULTS

FOXO4 expression was significantly lower in MDA-MB-231/DDP and BT-549/DDP cells. FOXO4 overexpression increased the sensitivity of TNBC cells to DDP. The PI3K class Ⅲ and Beclin-1 levels and LC3-II/LC3-I ratio elevated significantly in DDP-resistant cells. Moreover, the autophagic flux was enhanced in DDP-resistant cells. 3-MA enhanced the sensitivity of TNBC cells to DDP by inhibiting autophagy. Overexpression of FOXO4, treatment with 3-MA, and their combination significantly reduced the drug resistance index. FOXO4 directly targeted TGF-β1. Additionally, TGF-β1 knockdown inhibited autophagy and restored the sensitivity of DDP-resistant cells to DDP. Mechanistically, FOXO4 affected TNBC resistance to DDP by regulating autophagy and TGF-β1.

CONCLUSION

FOXO4 overexpression, in combination with autophagy inhibitors, can significantly improve the sensitivity of TNBC-resistant cells to DDP. These findings reveal the role and mechanism of FOXO4 in DDP sensitivity and may provide evidence for the development of TNBC therapies.

TNBC-DX genomic test in early-stage triple-negative breast cancer treated with neoadjuvant taxane-based therapy

BACKGROUND

Identification of biomarkers to optimize treatment strategies for early-stage triple-negative breast cancer (TNBC) is crucial. This study presents the development and validation of TNBC-DX, a novel test aimed at predicting both short- and long-term outcomes in early-stage TNBC. The objective of this study was to evaluate the association between TNBC-DX and efficacy outcomes [pathologic complete response (pCR), distant disease-free survival (DDFS) or event-free survival (EFS), and overall survival (OS)] in the validation cohorts.

METHODS

Information from 1259 patients with early-stage TNBC (SCAN-B, CALGB-40603, and BrighTNess) was used to establish the TNBC-DX scores. Independent validation of TNBC-DX was carried out in three studies: (i) WSG-ADAPT-TN; (ii) MMJ-CAR-2014-01; and (iii) NeoPACT, including 527 patients with stage I-III TNBC undergoing neoadjuvant chemotherapy. In WSG-ADAPT-TN, patients were randomized to receive nab-paclitaxel plus gemcitabine or carboplatin. In MMJ-CAR-2014-01, patients received carboplatin plus docetaxel. In NeoPACT, patients received carboplatin plus docetaxel and pembrolizumab.

RESULTS

TNBC-DX test was created incorporating the 10-gene Core Immune Gene module, the 4-gene tumor cell proliferation signature, tumor size, and nodal staging. In the two independent validation cohorts without pembrolizumab, the TNBC-DX pCR score was significantly associated with pCR after adjustment for clinicopathological variables and treatment regimen [odds ratio per 10-unit increment 1.34, 95% confidence interval (CI) 1.20-1.52, P < 0.001]. pCR rates for the TNBC-DX pCR-high, pCR-medium, and pCR-low categories were 56.3%, 53.6%, and 22.5% respectively (odds ratio for pCR-high versus pCR-low 3.48, 95% CI 1.72-7.15, P < 0.001). In addition, the TNBC-DX risk score was significantly associated with DDFS [hazard ratio (HR) high-risk versus low-risk 0.24, 95% CI 0.15-0.41, P < 0.001] and OS (HR 0.19, 95% CI 0.11-0.35, P < 0.001). In the validation cohort with pembrolizumab, the TNBC-DX scores were significantly associated with pCR, EFS, and OS.

CONCLUSIONS

TNBC-DX predicts pCR to neoadjuvant taxane-carboplatin in stage I-III TNBC and helps to forecast the patient's long-term survival in the absence of neoadjuvant anthracycline-cyclophosphamide, and independent of pembrolizumab use.

Molecular structure of polysaccharide mediated autophagy markers KIF23 and PRC1 proteins and their regulatory role in triple negative cancer through the p53 signaling pathway

As a process of intracellular degradation and recycling of its own components, abnormal regulation of autophagy has been strongly associated with the development of multiple cancer types, including triple-negative breast cancer. The amino acid sequences of KIF23 and PRC1 proteins were analyzed by bioinformatics method, their three-dimensional structures were predicted, and their interactions with polysaccharides were studied by molecular docking technology. The localization and expression patterns of KIF23 and PRC1 in cells were studied by cell biology techniques. By constructing breast cancer cell lines that stably overexpress or knock down KIF23 and PRC1, we evaluated the effect of these proteins on autophagy activity. Finally, molecular biological methods such as Western blot and real-time quantitative PCR were used to detect the expression changes of proteins related to p53 signaling pathway and the levels of autophagy markers such as LC3 and p62, thereby revealing the regulatory effects of KIF23 and PRC1 on autophagy of triple-negative breast cancer cells through p53 signaling pathway. The study found that the KIF23 and PRC1 proteins have complex three-dimensional structures, and their interactions with polysaccharides may affect their function during cell division and autophagy. In triple-negative breast cancer cells, overexpression of KIF23 and PRC1 significantly enhanced autophagy activity, while knockdown of these proteins inhibited autophagy. Further experiments showed that KIF23 and PRC1 regulate the expression of autophagy related proteins by influencing the activity of p53 signaling pathway. Overexpression of KIF23 and PRC1 led to inhibition of the p53 signaling pathway, while knocking down these proteins activated the p53 signaling pathway, which was consistent with reduced autophagy activity.

Copy number amplification of FLAD1 promotes the progression of triple-negative breast cancer through lipid metabolism

Triple-negative breast cancer (TNBC) is known for frequent copy number alterations (CNAs) and metabolic reprogramming. However, the mechanism by which CNAs of metabolic genes drive distinct metabolic reprogramming and affect disease progression remains unclear. Through an integrated analysis of our TNBC multiomic dataset (n = 465) and subsequent experimental validation, we identify copy number amplification of the metabolic gene flavin-adenine dinucleotide synthetase 1 (FLAD1) as a crucial genetic event that drives TNBC progression. Mechanistically, FLAD1, but not its enzymatically inactive mutant, upregulates the enzymatic activity of FAD-dependent lysine-specific demethylase 1 (LSD1). LSD1 subsequently promotes the expression of sterol regulatory element-binding protein 1 (SREBP1) by demethylating dimethyl histone H3 lysine 9 (H3K9me2). The upregulation of SREBP1 enhances the expression of lipid biosynthesis genes, ultimately facilitating the progression of TNBC. Clinically, pharmacological inhibition of the FLAD1/LSD1/SREBP1 axis effectively suppresses FLAD1-induced tumor progression. Moreover, LSD1 inhibitor enhances the therapeutic effect of doxorubicin and sacituzumab govitecan (SG). In conclusion, our findings reveal the CNA-derived oncogenic signalling axis of FLAD1/LSD1/SREBP1 and present a promising treatment strategy for TNBC.

Predicting progression in triple-negative breast cancer patients undergoing neoadjuvant chemotherapy: Insights from peritumoral radiomics

OBJECTIVE

To investigate whether radiomic features obtained from the intratumoral and peritumoral regions of pretreatment magnetic resonance imaging (MRI) can predict progression in patients with triple-negative breast cancer (TNBC) undergoing neoadjuvant chemotherapy (NAC) in comparison with the previously determined clinical score.

METHODS

This single-center retrospective study evaluated 224 women with TNBC who underwent NAC between 2010 and 2019. Women were randomly allocated to the training set (n = 169) for model development and the test set (n = 55) for model validation. The clinical score consisted of the histologic type, Ki-67 index, and degree of edema on T2-weighted imaging. Intratumoral and peritumoral radiomic features were extracted from T2-weighted images and the first- and last-phase images of dynamic contrast-enhanced MRI. The radiomics model was built using only radiomic features, whereas the combined model incorporated the clinical score along with radiomic features. The area under the receiver operating characteristic curve (AUC) was used to assess performance.

RESULTS

Progression occurred in 18 and five patients in the training and test sets, respectively. The radiomics model selected three radiomic features (two peritumoral and one intratumoral), while the combined model selected the clinical score and five radiomic features (four peritumoral and one intratumoral). Among the total radiomic features, Inverse Difference Normalized of the peritumoral region of the T2-weighted images, reflective of peritumoral heterogeneity, demonstrated the highest level of association with tumor progression. In the test set, the AUC values of the radiomics-only model, the combined model, and the clinical score were 0.592, 0.764, and 0.720, respectively. Compared to the clinical score, the radiomics-only model (0.720 vs. 0.592, p = 0.468) and the combined model (0.720 vs. 0.764, p = 0.553) did not show superior performance.

CONCLUSION

The radiomics features were not superior in predicting the progression of TNBC compared to the clinical score, although the peritumoral heterogeneity on T2-weighted images showed a potential.

Spatial Architecture of Single-Cell and Vasculature in Tumor Microenvironment Predicts Clinical Outcomes in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with limited treatment options, which warrants the identification of novel therapeutic targets. Deciphering nuances in the tumor microenvironment (TME) may unveil insightful links between antitumor immunity and clinical outcomes; however, such connections remain underexplored. Here, we employed a data set derived from imaging mass cytometry of 71 TNBC patient specimens at single-cell resolution and performed in-depth quantifications with a suite of multiscale computational algorithms. The TNBC TME reflected a heterogeneous ecosystem with high spatial and compositional heterogeneity. Spatial analysis identified 10 recurrent cellular neighborhoods-a collection of local TME characteristics with unique cell components. The prevalence of cellular neighborhoods enriched with B cells, fibroblasts, and tumor cells, in conjunction with vascular density and perivasculature immune profiles, could significantly enrich long-term survivors. Furthermore, relative spatial colocalization of SMAhi fibroblasts and tumor cells compared with B cells correlated significantly with favorable clinical outcomes. Using a deep learning model trained on engineered spatial data, we can predict with high accuracy (mean area under the receiver operating characteristic curve of 5-fold cross-validation = 0.71) how a separate cohort of patients in the NeoTRIP clinical trial will respond to treatment based on baseline TME features. These data reinforce that the TME architecture is structured in cellular compositions, spatial organizations, vasculature biology, and molecular profiles and suggest novel imaging-based biomarkers for the treatment development in the context of TNBC.

Targeting MYC for the treatment of breast cancer: use of the novel MYC-GSPT1 degrader, GT19630

BACKGROUND

Since MYC is one of the most frequently altered driver genes involved in cancer formation, it is a potential target for new anti-cancer therapies. Historically, however, MYC has proved difficult to target due to the absence of a suitable crevice for binding potential low molecular weight drugs.

OBJECTIVE

The aim of this study was to evaluate a novel molecular glue, dubbed GT19630, which degrades both MYC and GSPT1, for the treatment of breast cancer.

METHODS

The antiproliferative potential of GT19630 was evaluated in 14 breast cancer cell lines representing the main molecular subtypes of breast cancer. In addition, we also investigated the effects of GT19630 on apoptosis, cell cycle progression, cell migration, and degradation of the negative immune checkpoint protein, B7-H3.

RESULTS

GT19630 inhibited cell proliferation, blocked cell cycle progression, promoted apoptosis, and decreased cell migration at low nanomolar concentrations in breast cancer cell lines. By contrast, previously described MYC inhibitors such as specific MYC-MAX antagonists affected these processes at micromolar concentrations. Consistent with the ability of MYC to promote immune evasion, we also found that GT19630 degraded the negative immune checkpoint inhibitor, B7-H3.

CONCLUSIONS

We conclude that the novel molecular glue, GT19630, is a potent mediator of endpoints associated with cancer formation/progression. Its ability to degrade B7-H3 suggests that GT19630 may also promote host immunity against cancer. To progress GT19630 as a therapy for breast cancer, our finding should now be confirmed in an animal model system.

Protein lactylation within the nucleus independently predicts the prognosis of non‑specific triple‑negative breast cancer

Protein lactylation represents a pervasive post-translational modification prevalent in histones and diverse proteins, fostering tumor initiation and progression. Nonetheless, the impact of protein lactylation on the prognosis of non-specific triple-negative breast cancer (TNBC) remains uncertain. In the present study, the pan-lysine lactylation (panKlac) levels in cytoplasmic and nuclear compartments were semi-quantitatively examined using a tissue microarray encompassing 77 non-specific TNBC tissues. The association of the prognosis of patients with the panKlac levels in the cytoplasmic and nuclear compartments or other tumor attributes was assessed using Kaplan-Meier and Cox regression analyses. Furthermore, the molecular pathways involved in the promotional effect of lactylation on cell proliferation were determined through a transcriptomic analysis. The results indicated that the panKlac levels were markedly higher in tumor tissues than in para-tumor mammary regions and showed no significant correlations with various clinicopathological parameters, such as tumor dimension, lymph node involvement or histological grading. Notably, high panKlac levels within the nucleus served as an independent predictor of recurrence-free survival, whereas high cytoplasmic panKlac levels were a protective factor for patient survival. The panKlac levels were also markedly elevated in the TNBC cell line, MDA-MB-231. Additionally, glycolysis inhibition significantly reduced the global panKlac levels and concurrently diminished cell proliferation. According to the comprehensive transcriptomic analysis results, pathways related to ribosomal subunit biosynthesis/assembly and aminoacyl-tRNA biosynthesis were involved in the tumor-promoting mechanisms of lactylation. Further results revealed the oncogenic propensity of tyrosyl-tRNA synthetase 1 (YARS1) and its association with lactate production. Overall, Klac levels within the nucleus are an independent prognostic indicator for patients with non-specific TNBC. It is imperative to delve deeper into the roles and mechanisms of nuclear protein lactylation and YARS1 in non-specific TNBC.

The N6-methyladenosine writer METTL3 promotes breast cancer progression through YTHDF2-dependent posttranscriptional silencing of GSDMD

Cell pyroptosis is a form of programmed cell death, with Gasdermin-D (GSDMD) acting as its key executor. While activating pyroptosis represents a promising therapeutic strategy for cancer, the regulatory mechanisms governing GSDMD expression during cell death remain poorly understood. In this study, we identified METTL3 as a negative regulator of GSDMD-mediated pyroptosis, with high expression in breast cancer (BC) cells. YTHDF2 was found to recognize the m6A modification of GSDMD, thereby decreasing its stability. Finally, in vivo experiments further demonstrated the inhibitory effect of the METTL3 inhibitor STM2457 on tumors. Overall, these findings suggest that inhibition of METTL3 can enhance GSDMD-mediated pyroptosis and reveal a novel regulatory mechanism governing GSDMD expression, presenting a novel strategy for cancer treatment.

RNF31 induces paclitaxel resistance by sustaining ALYREF cytoplasmic-nuclear shuttling in human triple-negative breast cancer

BACKGROUND

Resistance to paclitaxel-based chemotherapy is the major obstacle in triple-negative breast cancer (TNBC) treatment. However, overcoming paclitaxel resistance remains an unsolved problem. The present study aimed to determine whether paclitaxel treatment impairs Aly/REF export factor (ALYREF) cytoplasmic-nuclear shuttling, its mechanism, and the role of ubiquitinated ALYREF in paclitaxel resistance.

METHODS

The subcellular proportion of ALYREF was detected in samples from patients with TNBC using immunohistochemistry to analyze the relationship between ALYREF distribution and paclitaxel response. Cell viability assays, immunofluorescence assays, quantitative real-time reverse transcription PCR assays, western blotting, and terminal deoxynucleotidyl transferase nick-end-labelling assays were conducted to measure the biological function of the subcellular proportion of ALYREF and E3 ligase ring finger protein 31 (RNF31) on paclitaxel sensitivity in TNBC. The synergistic effects of an RNF31 inhibitor plus paclitaxel on TNBC were evaluated. Cox regression models were adopted to assess the prognostic role of RNF31 in TNBC.

RESULTS

Herein, we showed that regulation of ALYREF cytoplasmic-nuclear shuttling is associated with the paclitaxel response in TNBC. In paclitaxel-sensitive TNBC, ALYREF was trapped in the cytoplasm by paclitaxel, while in paclitaxel-resistant TNBC, ALYREF was efficiently transported into the nucleus to exert its function, allowing the export of the mRNAs encoding paclitaxel-resistance-related factors, including tubulin beta 3 class III (TUBB3), stathmin 1 (STMN1), and microtubule-associated protein Tau (TAU), ultimately inducing paclitaxel resistance in TNBC. Mechanistically, we found that RNF31 interacts with and ubiquitinates ALYREF, which facilitates ALYREF nuclear transportation via importin 13 (IPO13) under paclitaxel treatment. Notably, the RNF31 inhibitor and paclitaxel synergistically repressed tumour growth in vivo and in TNBC patient-derived organoids. In addition, analysis of patients with TNBC showed that elevated RNF31 levels correlated with poor prognosis.

CONCLUSION

These data indicated that RNF31-mediated ALYREF ubiquitylation could represent a potent target to reverse paclitaxel resistance in TNBC.

KEY POINTS

RNF31 facilitated ALYREF-mediated PTX resistance in TNBC. RNF31 promoted ALYREF nuclear transport via IPO13 in response to PTX treatment, subsequently enhancing the export of mRNAs encoding PTX resistance-related factors, including TUBB3, STMN1, and TAU. Blocking RNF31 trapped ALYREF in the cytoplasm and induced TNBC cell death upon PTX treatment. Inhibiting RNF31 activity re-sensitized PTX-resistant TNBC to PTX treatment.

p21 Promoter Methylation Is Vital for the Anticancer Activity of Withaferin A

Breast cancer (BC) is a widespread malignancy that affects the lives of millions of women each year, and its resulting financial and healthcare hardships cannot be overstated. These issues, in combination with side effects and obstacles associated with the current standard of care, generate considerable interest in new potential targets for treatment as well as means for BC prevention. One potential preventive compound is Withaferin A (WFA), a traditional medicinal compound found in winter cherries. WFA has shown promise as an anticancer agent and is thought to act primarily through its effects on the epigenome, including, in particular, the methylome. However, the relative importance of specific genes' methylation states to WFA function remains unclear. To address this, we utilized human BC cell lines in combination with CRISPR-dCas9 fused to DNA methylation modifiers (i.e., epigenetic editors) to elucidate the importance of specific genes' promoter methylation states to WFA function and cancer cell viability. We found that targeted demethylation of promoters of the tumor suppressors p21 and p53 within MDA-MB-231/MCF7 cells resulted in around 1.7×/1.5× and 1.2×/1.3× increases in expression, respectively. Targeted methylation of the promoter of the oncogene CCND1 within MDA-MB-231/MCF7 cells resulted in 0.5×/0.8× decreases in gene expression. These changes to p21, p53, and CCND1 were also associated with decreases in cell viability of around 25%/50%, 5%/35%, and 12%/16%, respectively, for MDA-MB-231/MCF7 cells. When given in combination with WFA in both p53 mutant and wild type cells, we discovered that targeted methylation of the p21 promoter was able to modulate the anticancer effects of WFA, while targeted methylation or demethylation of the promoters of p53 and CCND1 had no significant effect on viability decreases from WFA treatment. Taken together, these results indicate that p21, p53, and CCND1 may be important targets for future in vivo studies that may lead to epigenetic editing therapies and that WFA may have utility in the prevention of BC through its effect on p21 promoter methylation independent of p53 function.

Discovery of dual PARP/NAMPT inhibitors for the treatment of BRCA wild-type triple-negative breast cancer

Simultaneous inhibition of poly(ADP-ribose) polymerase (PARP) and nicotinamide phosphoribosyltransferase (NAMPT) has been shown to be synergistically effective against breast cancer susceptibility (BRCA) wild-type triple-negative breast cancer (TNBC) through synthetic lethality, which may be explored to broaden the clinical utility of PARP inhibitors. Herein, we report the discovery of dual PARP/NAMPT inhibitors through a pharmacophore linking approach. The lead compound 13j with potent inhibitory activity against both PARP1 and NAMPT (IC50 = 0.8 and 18 nM, respectively) effectively inhibited the proliferation of TNBC MDA-MB-231 cells with wild-type BRCA at submicromolar level. Mechanically, 13j disrupted the homologous recombination repair (HRR) pathway, caused the accumulation of DNA double-strand breaks (DSBs) and ultimately induced apoptotic cell death. In addition, this compound exhibited potent inhibitory potency on the migration of MDA-MB-231 cells. This study demonstrates that compound 13j is a promising lead compound for the development of better PARP/NAMPT inhibitors to treat TNBC with wild-type BRCA.

Temporal and spatial composition of the tumor microenvironment predicts response to immune checkpoint inhibition

Immune checkpoint inhibition (ICI) has fundamentally changed cancer treatment. However, only a minority of patients with metastatic triple negative breast cancer (TNBC) benefit from ICI, and the determinants of response remain largely unknown. To better understand the factors influencing patient outcome, we assembled a longitudinal cohort with tissue from multiple timepoints, including primary tumor, pre-treatment metastatic tumor, and on-treatment metastatic tumor from 117 patients treated with ICI (nivolumab) in the phase II TONIC trial. We used highly multiplexed imaging to quantify the subcellular localization of 37 proteins in each tumor. To extract meaningful information from the imaging data, we developed SpaceCat, a computational pipeline that quantifies features from imaging data such as cell density, cell diversity, spatial structure, and functional marker expression. We applied SpaceCat to 678 images from 294 tumors, generating more than 800 distinct features per tumor. Spatial features were more predictive of patient outcome, including features like the degree of mixing between cancer and immune cells, the diversity of the neighboring immune cells surrounding cancer cells, and the degree of T cell infiltration at the tumor border. Non-spatial features, including the ratio between T cell subsets and cancer cells and PD-L1 levels on myeloid cells, were also associated with patient outcome. Surprisingly, we did not identify robust predictors of response in the primary tumors. In contrast, the metastatic tumors had numerous features which predicted response. Some of these features, such as the cellular diversity at the tumor border, were shared across timepoints, but many of the features, such as T cell infiltration at the tumor border, were predictive of response at only a single timepoint. We trained multivariate models on all of the features in the dataset, finding that we could accurately predict patient outcome from the pre-treatment metastatic tumors, with improved performance using the on-treatment tumors. We validated our findings in matched bulk RNA-seq data, finding the most informative features from the on-treatment samples. Our study highlights the importance of profiling sequential tumor biopsies to understand the evolution of the tumor microenvironment, elucidating the temporal and spatial dynamics underlying patient responses and underscoring the need for further research on the prognostic role of metastatic tissue and its utility in stratifying patients for ICI.

Monensin Inhibits Triple-Negative Breast Cancer in Mice by a Na+-Dependent Cytotoxic Action Unrelated to Cytostatic Effects

Triple-negative breast cancer (TNBC) represents the most aggressive breast cancer subtype, defined by its limited therapeutic options and poor outcomes. This study investigated the therapeutic potential of targeting Na+ homeostasis in TNBC cells to induce TNBC inhibition. For this purpose, BALB/c mice were inoculated with 4T1-Luc2 breast cancer cells and treated with the Na+ ionophore monensin (8 mg/kg) or vehicle alone. Tumor development and cellular Na+ content were assessed using vivo live imaging techniques, while intracellular Na+ variations and cytotoxicity were evaluated through live cell analysis. Monensin treatment increased Na+ levels in cancerous tissues and reduced TNBC mass (monensin: 0.146 ± 0.06; vehicle: 0.468 ± 0.2 cm3; p < 0.001). This treatment induced extensive necrosis in TNBC tumors while preserving the structural and functional integrity of healthy organs and maintaining the proliferative activity of both tumor and normal tissues. Monensin did not alter the expression of proliferating nuclear antigen (PCNA) in 4T1-Luc2 cells but triggered cytotoxicity preceded by intracellular Na+ accumulation. Na+-free conditions prevented both Na+ accumulation and 4T1-Luc2 cell death. Thus, monensin exerts its antitumor effects in TNBC through a Na+-dependent and tumor-specific cytotoxic mechanism, without inducing cytostatic effects on normal or transformed tissues. Collectively, these findings underscore the potential of Na+ ionophores as promising therapeutic agents for TNBC.

Mechanistic insights into pachymic acid's action on triple-negative breast Cancer through TOP2A targeting

Triple-negative breast cancer (TNBC) is characterized by the absence of estrogen and progesterone receptors, and lack of human epidermal growth factor receptor 2 (HER2) expression. Traditional Chinese medicine (TCM) has demonstrated promising efficacy in treating TNBC. This study explored the mechanisms of pachymic acid (PA) on TNBC by merging network pharmacology with experimental validation. We acquired Microarray data of TNBC from the Gene Expression Omnibus (GEO). The related targets of PA were predicted and screened using the following 6 databases: Swiss Target Prediction, HERB (Herbal Medicine Database), ETCM (Encyclopedia of Traditional Chinese Medicine), BATMAN (Bioinformatics Analysis Tool for Molecular Mechanism of Traditional Chinese Medicine), HIT (Herb Ingredients' Targets Database), and PharmMapper. The STRING interaction network analysis tool was used to create Protein-Protein Interaction (PPI) networks. Enrichment analysis included Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). We conducted a pan-cancer analysis, tumor immune microenvironment analysis, and molecular docking. We performed cell experimental, included cytotoxicity assay, apoptosis analysis, proliferation assay, and migration and invasion assays. PA has potential for treating TNBC with the target of TOP2A, and platinum drug resistance possibly serving as the KEGG pathway through which PA exerts its therapeutic effects. PA is involved in processes such as nuclear division, chromosome segregation, mitotic nuclear division, condensed chromosome formation, and protein C-terminus binding. PA probably exert its therapeutic effects through the tumor immune microenvironment, involving elements such as Dendritic cells activated, Eosinophils, Macrophages M0, Macrophages M1, and T cells CD4 memory activated. The therapeutic effects of PA may vary across different subtypes of TNBC such as TNBC-BL1, TNBC-Metaplastic, and TNBC-BL2. This study provides compelling evidence that PA holds significant promise as a therapeutic agent for TNBC, primarily through its action on TOP2A and its influence on the TNBC.

Fetal Mammary Gland Development and Offspring's Breast Cancer Risk in Adulthood

While advancements in early detection and improved access to care have significantly enhanced breast cancer survival rates, the disease remains a significant global malignancy, constituting approximately 12.5% of all new cancer cases and claiming nearly 700,000 lives in 2020. As a result, there is widespread consensus that the most sustainable solution lies in prevention. Indeed, preventive strategies, including lifestyle modifications and research into risk-reducing interventions, offer the potential to address the root causes of noncommunicable diseases such as breast cancer. While conventional wisdom has long attributed established risk factors for breast cancer to age, lifestyle, familial history, and reproductive factors, evidence highlights the maternal environment as a pivotal stage for fetal programming of disease risk, as elucidated in the developmental origins of health and disease (DOHaD) framework. Consequently, a growing body of research has been focused on elucidating epigenomic signatures that influence fetal development while shaping health outcomes and susceptibility to diseases later in life. This review aims to identify fetal mammary developmental genes that have been implicated in breast cancer etiology and the potential interplay of maternal environment in epigenetic programming of breast cancer risk in adulthood.

Secernin-2 Stabilizes Histone Methyltransferase KMT2C to Suppress Progression and Confer Therapeutic Sensitivity to PARP Inhibition in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a difficulty and bottleneck in the clinical treatment of breast cancer due to a lack of effective therapeutic targets. Herein, we first report that secernin 2 (SCRN2), an uncharacterized gene in human cancer, acts as a novel tumor suppressor in TNBC to inhibit cancer progression and enhance therapeutic sensitivity to poly(ADP-ribose) polymerase (PARP) inhibition both in vitro and in vivo. SCRN2 is downregulated in TNBC through chaperone-mediated autophagic degradation, and its downregulation is associated with poor patient prognosis. Moreover, SCRN2 impedes the proteasomal degradation of histone-lysine N-methyltransferase 2C (KMT2C) by recruiting Bcl2-associated athanogene 2 to block the interaction of KMT2C with E3 ubiquitin-protein ligase CHIP. Consistently, SCRN2 transcriptionally activates Bcl2-modifying factor by amplifying histone H3 monomethylation at lysine 4 at its enhancer, thereby inducing intrinsic apoptosis. Notably, KMT2C knockdown restores the impaired TNBC progression caused by SCRN2 overexpression both in vitro and in vivo. Furthermore, SCRN2 decreases the expression of key DNA repair-related genes and induces endogenous DNA damage, thus conferring therapeutic sensitivity of TNBC cells to PARP inhibition.   Collectively, these findings identify SCRN2 as a novel suppressor of TNBC, reveal its mechanism of action, and highlight its potential role in TNBC therapy.

Injectable supramolecular hydrogel co-loading abemaciclib/NLG919 for neoadjuvant immunotherapy of triple-negative breast cancer

The efficacy of cancer immunotherapy relies on a sufficient amount of functional immune cells. Triple-negative breast cancer lacks enough immune cell infiltration, and adjuvant therapy is necessary to prime anti-tumor immunity. However, the improvement in efficacy is unsatisfactory with concern about inducing systemic immunotoxicity. Herein, we create an abemaciclib-loaded supramolecular peptide hydrogel formed by peptide-drug amphiphiles for neoadjuvant immunotherapy of triple-negative breast cancer, where the amphiphile is a conjugate of a β-sheet-forming peptide with 1-cyclohexyl-2-(5H-imidazo[5,1-a]isoindol-5-yl)ethanol (NLG919), an inhibitor of indoleamine 2,3-dioxygenase 1. The hydrogel can be injected into the tumor site and retained for at least one week for the sustained release of both abemaciclib and NLG919. The abemaciclib is able to induce immunogenic cell death of cancer cells and increase interleukin-2 secretion by cytotoxic T lymphocytes. Abemaciclib adversely upregulates indoleamine 2,3-dioxygenase 1, whose kynurenine production activity is inhibited by NLG919. The neoadjuvant immunotherapy reduces tumor recurrence and pulmonary metastasis and prolongs the survival of animals. This hydrogel provides a potential platform for neoadjuvant immunotherapy of triple-negative breast cancer with reduced toxicity compared with free abemaciclib.