Triple negative breast cancer, an inherently aggressive disease, is further impaired by the limited therapeutic options and chemotherapy-resistance; hence, elucidating the signaling nodes underlying chemotherapy resistance is of major interest. Focusing on the differentially expressed genes in recurrent TNBC, we identified TRIM29, a ubiquitin ligase belonging to TRIM family, as a uniquely enriched protein in chemoresistant TNBC. Here, we demonstrate that chemoresistant TNBC cells are inherently aggressive, exhibiting elevated growth and migration potential compared to chemosensitive cells, and in particular, they possess higher TRIM29 expression whose expression level modulation results in altered chemosensitivity. TRIM29 overexpression reduces chemotherapy response whereas TRIM29 knockout not only increases chemosensitivity but also reduces TNBC tumor growth. Tumor-dissociated cells maintain TRIM29 knockout status as well as exhibit similar functional alterations as chemoresistant TNBC cells. Mechanistically, RNA-sequencing of parental-chemosensitive, chemoresistant-inherently overexpressing TRIM29 and chemoresistant-TRIM29 knockout TNBC cells reveals a unique set of genes (S100P, SERPINB3, SERPINB4, CEACAM5, CEACAM6 and CDH6) showing significant upregulation with the acquisition of chemoresistance and downregulation with the TRIM29 knockout. Furthermore, an enrichment of β-catenin pathway in chemoresistant TNBC cells is observed. We uncovered a functional network where S100P, a metastasis inducing secretory factor, bidirectionally interacts with TRIM29, and modulates the expression of SERPINB3, SERPINB4, CEACAM5, CEACAM6 as well as β-catenin pathway genes. Showing the functional importance, S100P inhibitor reduces the growth and mammosphere formation in chemoresistant TNBC. Moreover, combining β-catenin inhibitor with chemotherapy shows synergistic inhibition of chemoresistant TNBC cells. Indeed, higher expression of TRIM29, S100P and β-catenin associates with reduced recurrence free survival. This work proposes TRIM29 as an important node that modulates a unique gene network in chemoresistant TNBC and whose biological impact is mediated by modulation of S100P and β-catenin.

Breast cancer, particularly metastatic breast cancer (MBC), presents aggressive clinical challenges with limited treatment success. Immunotherapy has emerged as a promising approach, however, discrepancies between preclinical animal models and human cancers complicate translation to clinical outcomes. This systematic review and meta-analysis evaluated the effect of immunotherapy on primary and metastatic tumor regression in animal models of MBC and assessed the models' appropriateness and reproducibility to improve future preclinical study design. Following a preregistered protocol in PROSPERO (CRD42021207033), we conducted searches in MEDLINE, Embase, and Web of Science databases, yielding 2255 studies for title/abstract screening and 108 studies included after full-text screening. All included studies used mouse models, assessing primary outcomes through tumor volume or weight and metastatic outcomes via nodule count or bioluminescence. Only 14% of studies fully reported experimental animal characteristics, and 43% provided detailed experimental procedures. Of 105 articles (293 comparisons) included in the meta-analysis, pooled effect sizes indicated significant reductions in both primary and metastatic tumors. However, high heterogeneity across studies and wide prediction intervals suggested substantial variability in model responses to immunotherapy. Univariable and multivariable meta-regressions failed to significantly explain this heterogeneity, suggesting additional factors may influence outcomes. Trim-and-fill and Egger's regression tests indicated funnel plot asymmetry, implying potential publication bias and small study effects. While our analysis demonstrated positive effects of immunotherapy on MBC and highlighted variability in animal tumor models, addressing model-related heterogeneity and enhancing methodological transparency are essential to improve reproducibility and clinical translatability.

Triple-negative breast cancer (TNBC), is a highly aggressive tumor. Formosanin C (FC) is a diosgenin with immunomodulatory and antitumor properties, the precise mechanism through which it is against TNBC remains uncertain.

Clarifying the mechanism of FC against TNBC.

The impact of FC on two TNBC cell lines for 24 h was investigated through various techniques including the CCK8 assay, flow cytometry, transwell assay, scratch tests, immunoblot assay, and immunofluorescence. To elucidate the mechanism behind the anti-TNBC effect of FC, MDA-MB-231 cells were subjected to STAT3 overexpression. Moreover, the in vivo efficacy of FC was examined using a xenograft nude mice (BALB/C). Mice were divided into the control group (equal amount of PBS), the napabucasin group (5 mg/kg) and the FC groups (1 mg/kg, 2 mg/kg). The study duration was 30 days.

FC exhibited inhibitory effects against MDA-MB-231 and Hs578T cells. FC can decrease the migratory capacity of TNBC cells by inhibiting epithelial-mesenchymal transition (EMT). Meanwhile, we demonstrated that the inhibition of phosphorylation of STAT3 (Y705) is the crucial mechanism of FC against TNBC. Moreover, FC also hindered the polarization of macrophage M2.

This study is the first to show that FC restrains the EMT of TNBC cells by obstructing the STAT3 pathway and hinders the M2 polarization of macrophages and immune evasion. Therefore, FC holds the possibility of being utilized as a therapeutic remedy for TNBC.

Programmed cell death (PCD) dynamically influences breast cancer (BC) prognosis through interactions with the tumor microenvironment (TME). We investigated 13 PCD patterns to decipher their prognostic impact and mechanistic links to TME-driven outcomes. Our study aimed to explore the complex mechanisms underlying these interactions and establish a prognostic prediction model for breast cancer.

Using TCGA and METABRIC datasets, we integrated single-sample gene set enrichment analysis (ssGSEA), weighted gene co-expression network analysis (WGCNA), and Least Absolute Shrinkage and Selection Operator (LASSO) to explore PCD-TME interactions. Multi-dimensional analyses included immune infiltration, genomic heterogeneity, and functional pathway enrichment.

Our results indicated that high apoptosis and pyroptosis activity, along with low autophagy, correlated with favorable prognosis, which was driven by enhanced anti-tumor immunity, including more M1 macrophage polarization and activated CD8+ T cells in TME. PCD-related genes could promote tumor metastasis and poor prognosis via VEGF/HIF-1/MAPK signaling and immune response, including Th1/Th2 cell differentiation, while new tumor event occurrences (metastasis/secondary cancers) were linked to specific clinical features and gene mutation spectrums, including TP53/CDH1 mutations and genomic instability. We constructed a six-gene LASSO model (BCAP31, BMF, GLUL, NFKBIA, PARP3, PROM2) to predict prognosis and identify high-risk BC patients (for five-year survival, AUC = 0.76 in TCGA; 0.74 in METABRIC). Therein, the high-risk subtype patients demonstrated a poorer prognosis, also characterized by lower microenvironment matrix and downregulated immunocyte infiltration. These six gene signatures also showed prognostic value with significant differential expression in gene and protein levels of BC samples.

Our study provided a comprehensive landscape of the cancer survival difference and related PCD-TME interaction axis and highlighted that high-apoptosis/pyroptosis states caused favorable prognosis, underlying mechanisms closely related with the TME where anti-tumor immunity would be beneficial for patient prognosis. These findings highlighted the model's potential for risk stratification in BC.

Triple negative breast cancer (TNBC) has the worst prognosis among breast cancers due to its aggressive nature and the absence of targeted treatments. Development of novel anti-cancer drugs for TNBC faces challenges stemming from its heterogeneity and high potential for metastasis. Metabolomics can be a useful technology in finding novel therapeutic targets and probing the heterogeneity of TNBC. Metabolomics has been enabled by advancements in mass spectrometry (MS)-based platforms that facilitated comprehensive profiling of TNBC metabolism. This review provides an overview of metabolomic changes in TNBC with emphasis on lipid alterations, and describes the key MS analytical techniques, providing the necessary background for examining the role of lipids in TNBC development.

Cancer-associated fibroblasts (CAFs) are the most abundant stromal cellular component in the tumor microenvironment (TME). CAFs contribute to tumorigenesis and have been proposed as targets for anticancer therapies. Similarly, dysregulation of SUMO machinery components can disrupt the balance of SUMOylation, contributing to tumorigenesis and drug resistance in various cancers, including breast cancer. We explored the role of SUMOylation in breast CAFs and evaluated its potential as a therapeutic strategy in breast cancer.

We used pharmacological and genetic approaches to analyse the functional crosstalk between breast tumor cells and CAFs. We treated breast CAFs with the SUMO1 inhibitor ginkgolic acid (GA) at two different concentrations and conditioned media was used to analyse the proliferation, migration, and invasion of breast cancer cells from different molecular subtypes. Additionally, we performed quantitative proteomics (SILAC) to study the differential signalling pathways expressed in CAFs treated with low or high concentrations of GA. We confirmed these results both in vitro and in vivo. Moreover, we used samples from metastatic breast cancer patients to evaluate the use of GA as a therapeutic strategy.

Inhibition of SUMOylation with ginkgolic acid (GA) induces death in breast cancer cells but does not affect the viability of CAFs, indicating that CAFs are resistant to this therapy. While CAF viability is unaffected, CAF-conditioned media (CM) is altered by GA, impacting tumor cell behaviour in different ways depending on the overall degree to which SUMO1-SUMOylated proteins are dysregulated. Breast cancer cell lines exhibited a concentration-dependent response to conditioned media (CM) from CAFs. At a low concentration of GA (10 µM), there was an increase in proliferation, migration and invasion of breast cancer cells. However, at a higher concentration of GA (30 µM), these processes were inhibited. Similarly, analysis of tumor development revealed that at 10 µM of GA, the tumors were heavier and there was a greater degree of metastasis compared to the tumors treated with the higher concentration of GA (30 µM). Moreover, some of these effects could be explained by an alteration in the activity of the GTPase Rac1 and the activation of the AKT signalling pathway. The results obtained using SILAC suggest that different concentrations of GA affected cellular processes differentially, possibly influencing the secretome of CAFs. Treatment of metastatic breast cancer with GA demonstrated the use of SUMOylation inhibition as an alternative therapeutic strategy.

The study highlights the importance of SUMOylation in the tumor microenvironment, specifically in cancer-associated fibroblasts (CAFs). Targeting SUMOylation in CAFs affects their signalling pathways and secretome in a concentration-dependent manner, regulating the protumorigenic properties of CAFs.

Molecular subtyping of breast carcinoma and Ki-67 index has gained prominence in the recent past, as conventional factors such as surgical margins, tumor size, grade and lymph node involvement, are not sufficient to assess prognosis and make better therapeutic decisions. These subtypes include Luminal A, Luminal B, Triple Negative breast cancer (TNBC), and HER2-enriched subtypes. This study aimed to analyze the molecular subtypes and Ki-67 index in prognosis of breast carcinoma.

This retrospective study was conducted in the department of Pathology in a tertiary care center over a period of 3 years. All invasive breast carcinomas (IDC) which were molecularly subtyped and Ki-67 indexed were included in the study. Statistical analysis was done using SPSS software.

Out of 253 cases, 231 cases (91.3%) were IDC-NST and 22 cases (8.7%) were special types. Metaplastic and papillary tumors were associated with higher grade and high Ki-67 value. TNBC (35.2%) showing a majority of high-grade tumors, was the most prevalent subtype followed by Luminal A (32%) showing low grade, unlike other studies which showed luminal A to be most common subtype. The rare PR positive subtype was also observed in our study.

TNBC and HER 2-positive subtypes exhibited bad prognosis with higher histological grade, high Ki-67 index and higher age at presentation whereas Luminal A subtype, with lower grade and low Ki-67 index showed better prognosis. Thus, this vast array of predictive and prognostic information obtained by molecular subtyping will help clinicians in not only distinguishing between low-risk and high-risk subtypes but also in customization of the treatment and follow-up of the patients.

Tumors formed by the unchecked growth of breast cells are known as breast cancer. The second most frequent cancer in the world is breast cancer. It is the most common cancer among females. In 2022, 2,296,840 women were diagnosed with breast cancer. The therapy of breast cancer is evolving through the development of Poly (ADP-ribose) polymerase (PARP) inhibitors, which are offering people with specific genetic profiles new hope as research into the disease continues. It focuses on patients with BRCA1 and BRCA2 mutations. This review summarizes the most recent research on the mechanisms of action of PARP inhibitors and their implications for breast cancer therapy. We review how therapeutic applications are developing and highlight recent studies showing the effectiveness of these medicines whether used alone or in combination. Furthermore, the significance of customized therapy is highlighted in enhancing patient outcomes as we address the function of genetic testing in identifying candidates for PARP inhibition. Recommendations for future research areas to maximize the therapeutic potential of PARP inhibitors are also included, along with challenges and limits in their clinical usage. The objective of this review is to improve our comprehension of the complex interaction between breast cancer biology and PARP inhibition. This knowledge will help to guide screening approaches, improve clinical practice, and support preventive initiatives for people at risk.

Breast cancer (BC) is a highly heterogeneous disease with diverse molecular subtypes, which complicates prognosis and treatment. In this study, we performed a multi-omics clustering analysis using the Cancer Integration via MultIkernel LeaRning (CIMLR) method on a large BC dataset from The Cancer Genome Atlas (TCGA) to identify key prognostic biomarkers. We identified three genes-LMO1, PRAME, and RSPO2-that were significantly associated with poor prognosis in both the TCGA dataset and an additional dataset comprising 146 metastatic BC patients. Patients' stratification based on the expression of these three genes revealed distinct subtypes with markedly different overall survival (OS) outcomes. Further validation using almost 2000 BC patients' data from the METABRIC dataset and RNA sequencing data from therapy-resistant cell lines confirmed the upregulation of LMO1 and PRAME, respectively, in patients with worse prognosis and in resistant cells, also suggesting their potential role in drug resistance. Our findings highlight LMO1 and PRAME as potential biomarkers for identifying high-risk BC patients and informing targeted treatment strategies. This study provides valuable insights into the multi-omics landscape of BC and underscores the importance of personalized therapeutic approaches based on molecular profiles.

The proliferation-specific oncogenic transcription factor, FOXM1 is overexpressed in primary and recurrent breast tumors across all breast cancer (BC) subtypes. Intriguingly, FOXM1 overexpression was found to be highest in Triple-negative breast cancer (TNBC), the most aggressive BC with the worst prognosis. However, FOXM1-mediated TNBC pathogenesis is not completely elucidated. Single nucleotide polymorphisms (SNPs) are the most common genetic variations causing functional and structural aberrations in proteins enhancing cancer susceptibility. This computational investigation attempted to identify the malignant FOXM1 non-synonymous SNPs (nsSNPs) and evaluate their role in affecting the conformational and functional stability, evolutionary conservation, post-translational modifications, and malignant susceptibility of the protein. Out of a huge data pool of 8826 FOXM1 SNPs using several in-silico sequence-based tools and structural approaches, four SNPs viz. E235Q, R256C, G429E and S756P were identified as pathogenic nsSNPs and among the shortlisted variants molecular dynamics simulations identified E235Q as the most damaging malignant SNP, followed by S756P. Additionally, the defective drug and DNA binding motif of E235Q and S756P were also determined in our study. Thus, although further in-vitro validations are awaited the findings of this in-silico work can be used as a blueprint for malignant nsSNP identification of FOXM1 aiding in clinical TNBC therapeutics.

Immune checkpoint inhibitors (ICIs), used in cancer immunotherapy, enhance the immune system's ability to attack cancer cells. However, this activation can lead to severe immune-associated adverse events due to overactivation. In autoimmune diseases, the immune system mistakenly targets the body's tissues, producing autoantibodies that cause inflammation and tissue damage. Despite the increasing use of ICIs, limited information exists on their effects and potential harms in patients with active autoimmune diseases, making it challenging to predict outcomes and manage risks for these patients.

We report a case of a patient with breast cancer presenting with a rash and muscle weakness. The simultaneous onset of these symptoms, along with the rapid growth of the breast tumor, led to a diagnosis of tumor-associated dermatomyositis (DM). The patient presented with locally advanced triple-negative breast cancer and received preoperative chemotherapy, including ICIs.

The administration of preoperative chemotherapy, including ICIs, to a patient with breast cancer and tumor-associated DM was found to be a safe and effective treatment approach. There is a need to better understand the interplay between ICIs and autoimmune diseases and to develop safe and effective treatment strategies for this unique patient population.

Approximately 20% of all breast cancer cases are classified as triple-negative breast cancer (TNBC), which represents the most challenging subtype due to its poor prognosis and high metastatic rate. Caffeic acid phenethyl ester (CAPE), the main component extracted from propolis, has been reported to exhibit anticancer activity across various tumor cell types. This study aimed to investigate the effects and mechanisms of CAPE on TNBC.

MDA-MB-231 and MDA-MB-468 cells were treated with CAPE. CCK8 and colony formation assays were performed to analyze cell proliferation. Western blot, TUNEL and Annexin V-FITC/PI staining methods were employed to assess cell apoptosis. ROS, MDA, SOD, GSH, C11-bodipy staining, along with measurements of GPX4 and Ferritin levels, were utilized for ferroptosis detection. Western blot and immunofluorescence analysis were used to assess key regulatory molecules. The cells were subjected to treatments involving ferroptosis inhibition, AMPK inhibition, or Foxo3 inhibition, followed by CAPE administration to assess cell proliferation, apoptosis, and ferroptosis. Tumor xenografts were used to evaluate the antitumor efficacy of CAPE.

CAPE not only suppressed cell proliferation but also promoted apoptosis followed by ferroptosis. Co-incubation with Fer-1 (a ferroptosis inhibitor) diminished CAPE's suppressive effects on proliferation and apoptosis induction. CAPE treatment enhanced the phosphorylation of AMPK and promoted the nuclear translocation of Foxo3. Inhibition of both AMPK and Foxo3 by siRNAs or inhibitors (Compc, TIC10) reversed the growth retardation induced by CAPE as well as its pro-apoptotic effects leading to ferroptosis. Specifically, AMPK inhibition abrogated the CAPE-induced nuclear translocation of Foxo3. CAPE significantly inhibited tumor growth in nude mice bearing TNBC xenografts.

CAPE possesses a resistance effect on TNBC via activation of AMPK and Foxo3 signaling pathways.

The extensive heterogeneity and the limited availability of effective targeted therapies contribute to the challenging prognosis and restricted survival observed in triple-negative breast cancer (TNBC). Recent research indicates the aberrant expression of diverse tyrosine kinases (TKs) within this cancer, contributing significantly to tumor cell proliferation, survival, invasion, and migration. The contemporary paradigm shift towards precision medicine has highlighted TKs and their receptors as promising targets for pharmacotherapy against a range of malignancies, given their pivotal roles in tumor initiation, progression, and advancement. Intensive investigations have focused on various monoclonal antibodies (mAbs) and small molecule inhibitors that specifically target proteins such as epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), vascular endothelial growth factor receptor (VEGFR), cellular mesenchymal-epithelial transition factor (c-MET), human epidermal growth factor receptor 2 (HER2), among others, for combating TNBC. These agents have been studied both in monotherapy and in combination with other chemotherapeutic agents. Despite these advances, a substantial terrain of unexplored potential lies within the realm of TK targeted therapeutics, which hold promise in reshaping the therapeutic landscape. This review summarizes the various TK targeted therapeutics that have undergone scrutiny as potential therapeutic interventions for TNBC, dissecting the outcomes and revelations stemming from diverse clinical investigations. A key conclusion from the umbrella clinical trials evidences the necessity for in-depth molecular characterization of TNBCs for the maximum efficiency of TK targeted therapeutics, either as standalone treatments or a combination. Moreover, our observation highlights that the outcomes of TK targeted therapeutics in TNBC are substantially influenced by the diversity of the patient cohort, emphasizing the prioritization of individual patient genetic/molecular profiles for precise TNBC patient stratification for clinical studies.

To assess proportions of metastatic recurrence in women initially diagnosed with non-metastatic breast cancer by stage at diagnosis, breast cancer subtype, calendar period and age.

A systematic search of MEDLINE and Web of Science databases (January 2010-12 May 2022) was conducted. Studies reporting the proportion of distant metastatic recurrence in women with non-metastatic breast cancer were identified and outcomes and characteristics were extracted. Risk of bias was assessed independently by two reviewers. Random-effects meta-analyses of proportions were used to calculate pooled estimates and 95% confidence intervals (CIs).

193 studies covering over 280,000 patients were included in the main analysis. Pooled proportions of metastatic recurrence increased with longer median follow-up time from 12.2% (95% CI 10.5-14.0%) at 1-4 years post diagnosis, 14.3% (95% CI 12.9-15.7%) at 5-9 years to 23.3% (95% CI 20.1-26.8) at 10 years or more. Regional variation was observed with pooled estimates ranging from 11.0% (95% CI 8.5-13.7%) in Europe to 26.4% (95% CI 16.7-37.4%) in Africa (1-4 years follow-up). Proportions of recurrence were higher in studies with diagnosis before 2000 (22.2%, 95% CI 15.1-30.3) compared to studies with diagnosis from 2000 onwards (12.8%, 95% CI 11.7-14.0). At 1-4 years median follow-up, pooled proportions of metastatic recurrence were higher in women with hormone receptor negative (15.2%, 95% CI 12.0-18.7%) compared with receptor positive disease (9.6%, 95% CI 6.2-13.6%) and in women with locally advanced (33.2%, 95% CI 24.7-42.3%) relative to early disease at initial diagnosis (4.8%, 95% CI 2.5-7.8%). Proportions were higher in those under 50 years compared with 70+ years, 18.6% (95% CI 15.9-21.4%) versus 13.3% (95% CI 9.2, 18.0%), respectively. Heterogeneity was high in all meta-analyses and results should be interpreted with caution.

Higher proportions of metastatic recurrence in patients initially diagnosed at an advanced stage and in earlier calendar period emphasises the importance of early detection and treatment advancements. As the global number of breast cancer survivors increases, research and health policy efforts should be directed towards timely diagnosis and access to effective treatments and care.

PROSPERO CRD42022314500.

It has been previously established that breast cancer cells exhibit high expression of the monocarboxylate (lactate) transporters (MCT1 and/or MCT4) and carbonic anhydrase IX (CAIX) and form a functional metabolon for proton-coupled lactate export, thereby stabilizing intracellular pH. CD147 is the MCT accessory protein that facilitates the creation of the MCT/CAIX complex. This study describes how the small molecule Beta-Galactose 2C (BGal2C) blocks the physical and functional interaction between CAIX and either MCT1 or MCT4 in Xenopus oocytes, which reduces the rate of proton and lactate flux with an IC50 of ~90 nM. This value is similar to the Ki for inhibition of CAIX activity. Furthermore, it is shown that BGal2C blocks hypoxia-induced lactate transport in MDA-MB-231 and MCF-7 breast cancer cells, both of which express CAIX. As in oocytes, BGal2C interferes with the physical interaction between CAIX and MCTs in both cell types. Finally, X-ray crystallographic studies highlight unique interactions between BGal2C and a CAIX-mimic that are not observed within the CAII active site and which may underlie the strong specificity of BGal2C for CAIX. These studies demonstrate the utility of a novel sulfonamide in interfering with elevated proton and lactate flux, a hallmark of many solid tumors.

The epidermal growth factor receptor 1 (EGFR) plays a crucial role in the progression of various malignant tumors and is considered a potential target for treating triple-negative breast cancer (TNBC). However, the effectiveness of representative tyrosine kinase inhibitors (TKIs) used in EGFR-targeted therapy is limited in TNBC patients. In our study, we observed that the TNBC cell lines MDA-MB-231 and MDA-MB-468 exhibited resistance to Gefitinib. Treatment with Gefitinib caused an upregulation of Fascin-1 (FSCN1) protein expression and a downregulation of miR-221-3p in these cell lines. However, sensitivity to Gefitinib was significantly improved in both cell lines with either inhibition of FSCN1 expression or overexpression of miR-221-3p. Our luciferase reporter assay confirmed that FSCN1 is a target of miR-221-3p. Moreover, Gefitinib treatment resulted in an upregulation of phosphorylated signal transducer and activator of transcription 3 (p-STAT3) in MDA-MB-231 cells. Using Stattic, a small-molecule inhibitor of STAT3, we observed a significant enhancement in the inhibitory effect of Gefitinib on the growth, migration, and invasion of MDA-MB-231 cells. Additionally, Stattic treatment upregulated miR-221-3p expression and downregulated FSCN1 mRNA and protein expression. A strong positive correlation was noted between the expression of STAT3 and FSCN1 in breast cancer tissues. Furthermore, patients with high expression levels of both STAT3 and FSCN1 had a worse prognosis. Our findings suggest that elevated FSCN1 expression is linked to primary resistance to EGFR TKIs in TNBC. Moreover, we propose that STAT3 regulates the expression of miR-221-3p/FSCN1 and therefore modulates resistance to EGFR TKI therapy in TNBC. Combining EGFR TKI therapy with inhibition of FSCN1 or STAT3 may offer a promising new therapeutic option for TNBC.

To evaluate the feasibility of using a multigene signature to tailor individualised adjuvant therapy for patients with operable triple negative breast cancer.

Randomised, multicentre, open label, phase 3 trial.

7 cancer centres in China between 3 January 2016 and 17 July 2023.

Female patients aged 18-70 years with early triple negative breast cancer after definitive surgery.

After risk stratification using the integrated signature, patients at high risk were randomised (1:1) to receive an intensive adjuvant treatment comprising four cycles of docetaxel, epirubicin, and cyclophosphamide followed by four cycles of gemcitabine and cisplatin (arm A; n=166) or a standard treatment of four cycles of epirubicin and cyclophosphamide followed by four cycles of docetaxel (arm B; n=170). Patients at low risk received the same adjuvant chemotherapy as arm B (arm C; n=168).

The primary endpoint was disease-free survival in the intention-to-treat analysis for arm A versus arm B. Secondary endpoints included disease-free survival for arm C versus arm B, recurrence-free survival, overall survival, and safety.

Among the 504 enrolled patients, 498 received study treatment. At a median follow-up of 45.1 months, the three year disease-free survival rate was 90.9% for patients in arm A and 80.6% for patients in arm B (hazard ratio 0.51, 95% confidence interval (CI) 0.28 to 0.95; P=0.03). The three year recurrence-free survival rate was 92.6% in arm A and 83.2% in arm B (hazard ratio 0.50, 95% CI 0.25 to 0.98; P=0.04). The three year overall survival rate was 98.2% in arm A and 91.3% in arm B (hazard ratio 0.58, 95% CI 0.22 to 1.54; P=0.27). The rates of disease-free survival (three year disease-free survival 90.1% v 80.6%; hazard ratio 0.57, 95% CI 0.33 to 0.98; P=0.04), recurrence-free survival (three year recurrence-free survival 94.5% v 83.2%; 0.42, 0.22 to 0.81; P=0.007), and overall survival (three year overall survival 100% v 91.3%; 0.14, 0.03 to 0.61; P=0.002) were significantly higher in patients in arm C than in those in arm B with the same chemotherapy regimen. The incidence of grade 3-4 treatment related adverse events were 64% (105/163), 51% (86/169), and 54% (90/166) for arms A, B, and C, respectively. No treatment related deaths occurred.

The multigene signature showed potential for tailoring adjuvant chemotherapy for patients with operable triple negative breast cancer. Intensive regimens incorporating gemcitabine and cisplatin into anthracycline/taxane based therapy significantly improved disease-free survival with manageable toxicity.

ClinicalTrials.gov NCT02641847.

Breast cancer treatments are based on prognostic clinicopathologic features that form the basis for therapeutic guidelines. Although the utilization of these guidelines has decreased breast cancer-associated mortality rates over the past three decades, they are not adequate for individualized therapy. Radiation therapy (RT) is the backbone of breast cancer treatment. Although a highly successful therapeutic modality clinically, from a biological perspective, preclinical studies have shown RT to have the potential to alter tumor cell phenotype, immunogenicity, and the surrounding microenvironment, potentially changing the behavior of cancer cells and resulting in a significant variation in RT response. This review presents the recent advances in revealing the complex molecular changes induced by RT in the treatment of breast cancer and highlights the complexities of translating this information into clinically relevant tools for improved prognostic insights and the revelation of novel approaches for optimizing RT.

Current literature was reviewed with a focus on recent advances made in the elucidation of tumor-associated radiation-induced molecular changes across molecular, genetic, and proteomic bases. This review was structured with the aim of providing an up-to-date overview over the very broad and complex subject matter of radiation-induced molecular changes and radioresistance, familiarizing the reader with the broader issue at hand.

The subject of radiation-induced molecular changes in breast cancer has been broached from various physiological focal points including that of the immune system, immunogenicity and the abscopal effect, tumor hypoxia, breast cancer classification and subtyping, molecular heterogeneity, and molecular plasticity. It is becoming increasingly apparent that breast cancer clinical subtyping alone does not adequately account for variation in RT response or radioresistance. Multiple components of the tumor microenvironment and immune system, delivered RT dose and fractionation schedules, radiation-induced bystander effects, and intrinsic tumor physiology and heterogeneity all contribute to the resultant RT outcome.

Despite recent advances and improvements in anticancer therapies, tumor resistance remains a significant challenge. As new analytical techniques and technologies continue to provide crucial insight into the complex molecular mechanisms of breast cancer and its treatment responses, it is becoming more evident that personalized anticancer treatment regimens may be vital in overcoming radioresistance.

Triple-negative breast cancer (TNBC) accounts for disproportionately poor outcomes in breast cancer, driven by a subset of rapid-relapse TNBC (rrTNBC) with marked chemoresistance, rapid metastatic spread, and poor survival. This study aimed to develop and validate a nomogram based on clinicopathological characteristics to predict rapid relapse in TNBC patients treated with neoadjuvant chemotherapy (NAC) first.

The clinicopathological data of 504 TNBC patients treated with NAC first in Tianjin Medical University Cancer Hospital were analyzed retrospectively, with 109 rapid relapsed patients, and 395 non-rapid relapsed patients, respectively. Based on clinicopathologic characteristics, and follow-up data were analyzed. The independent predictors of clinicopathological characteristics were identified by logistic regression analysis and then used to build a nomogram. The concordance index (C-index), the area under the curve (AUC) of receiver operating characteristic (ROC), and calibration plots were used to evaluate the performance of the model.

Univariate and multivariate logistic regression analyses showed that age at diagnosis (age≥50 years, OR = 0.325,95% CI:0.137-0.771), Nodal staging (N3 staging, OR = 13.669,95% CI:3.693-50.592),sTIL expression levels (sTIL intermediate expression, OR = 0.272,95% CI:0.109-0.678; sTIL high expression, OR = 0.169,95% CI:0.048-0.594), and NAC response (ORR, OR = 0.059,95% CI:0.024-0.143) were independent predictors of rapid relapse in TNBC patients treated with NAC firstly. Among these independent predictors, age ≥ 50 years, sTIL intermediate expression, sTIL high expression, and ORR in NAC were independent protective factors for rapid relapse in TNBC NAC patients. N3 staging was an independent risk factor for rapid relapse in TNBC NAC patients. The ROC curve, calibration curve, and decision curve analysis were used to validate the model. The C-Index of the training sets and validation sets were 0.938 and 0.910, respectively. The Brier scores of the training sets and validation sets were 0.076 and 0.097, respectively.

This study developed and verified a nomogram for predicting rapid relapse in TNBC NAC patients, and the predictive model had high discrimination and accuracy.

Acinic cell carcinoma (AciCC) of the breast is a rare malignant epithelial neoplasm, with approximately 60 cases reported in the literature. It predominantly affects women and exhibits significant histological heterogeneity. The diagnosis of breast AciCC is primarily based on the presence of eosinophilic and/or basophilic granular cytoplasm and markers of serous acinar differentiation. Despite being considered a low-grade variant of conventional triple-negative breast cancer (TNBC), over 25% of patients with breast AciCC have adverse clinical outcomes. Additionally, in early research, microglandular adenosis (MGA) and atypical MGA were considered potential precursors for various breast cancers, including intraductal carcinoma, invasive ductal carcinoma, adenoid cystic carcinoma, metaplastic carcinoma, and AciCC. Similarly, some studies have proposed that breast AciCC should be considered a type of carcinoma developing in MGA with acinic cell differentiation rather than a distinct entity. Therefore, the pathogenesis of breast AciCC has not yet been clarified. Moreover, to the best of our knowledge, the literature has not summarized the latest prognosis and treatment of breast AciCC. In this review, we synthesized the current literature and the latest developments, aiming at exploring the clinicopathology, histological origin, molecular features, prognosis, and treatment of breast AciCC from a novel perspective.

Heparin-binding growth factor (HB-EGF) is a member of the epidermal growth factor (EGF) ligand family which has a crucial role in women's health. However, there is a lack of comprehensive review to summarize the significance of HB-EGF. Therefore, this work first described the expression patterns of HB-EGF in the endometrium and ovary of different species and gestational time. Then, the focus was on exploring how it promotes the successful implantation and regulates the process of decidualization and the function of ovarian granulosa cells as an intermediate molecule. Otherwise, we also focused on the clinical and prognostic significance of HB-EGF in female-related cancers (including ovarian cancer, cervical cancer, and endometrial cancer) and breast cancer. Lastly, the article also summarizes the current drugs targeting HB-EGF in the treatment of ovarian cancer and breast cancer. Overall, these studies found that the expression of HB-EGF in the endometrium is spatiotemporal and species-specific. And it mediates the dialogue between the blastocyst and endometrium, promoting synchronous development of the blastocyst and endometrium as an intermediate molecule. HB-EGF may serve as a potentially valuable prognostic clinical indicator in tumors. And the specific inhibitor of HB-EGF (CRM197) has a certain anti-tumor ability, which can exert synergistic anti-tumor effects with conventional chemotherapy drugs. However, it also suggests that more research is needed in the future to elucidate its specific mechanisms and to accommodate clinical studies with a larger sample size to clarify its clinical value.

Triple-negative breast cancer (TNBC) is a highly aggressive type of breast cancer with poor prognosis, and neoadjuvant therapy (NAT) has emerged as an important component in managing advanced-stage patients by providing surgical opportunities and improving survival outcomes. A search of publications on NAT for TNBC from 2002 to 2023 was conducted through the Web of Science core collection. A comprehensive bibliometric analysis was conducted on the data using CiteSpace, VOSviewer, and Bibliometrix. The analysis revealed a continuous and steady growth in the number of articles published in this field over the past 20 years. The United States has made significant contributions to this field, with The University of Texas MD Anderson Cancer Center publishing the most articles. Loibl, S. from Germany was found to be the most published author with 54 articles. Analysis of the journals showed that the Journal of Clinical Oncology is the most cited journal. Combined with the keyword co-occurrence analysis and clustering analysis, current research topic focuses on treatment regimens and disease prognosis. Dual-map overlay of the journals indicates that the research trend is gradually shifting from molecular biology and genetics to immunology and clinical research. Combination therapy, including immunotherapy, may be the future direction for NAT treatment of TNBC. Overall, this study provides valuable insights into the current research status, latest advancements, and emerging development trend of NAT for TNBC.

The standard treatment for early-stage breast cancer involves breast-conserving surgery followed by adjuvant radiotherapy. However, approximately 20 % of patients experience distant metastasis, and adjuvant radiotherapy often leads to radiation-induced skin fibrosis (RISF). In this study, we develop an on-site injectable formulation composed of selenocystamine (SeCA) and hyaluronic acid (HyA), referred to as SeCA cross-linked HyA (SCH) agent, and investigate its potential to mitigate metastasis and prevent RISF associated with breast cancer therapy. SCH agents are synthesized using the nanoprecipitation method to modulate cell-cell tight junctions and tissue inflammation. The toxicity assessments reveal that SCH agents with a higher Se content (Se payload 17.4 μg/mL) are well tolerated by L929 cells compared to SeCA (Se payload 3.2 μg/mL). In vitro, SCH agents significantly enhance cell-cell tight junctions and effectively mitigate migration and invasion of breast cancer cells (4T1). In vivo, SCH agents mitigate distant lung metastasis. Furthermore, in animal models, SCH agents reduce RISF and promote wound repair. These findings highlight the potential of SCH agents as a novel therapeutic formulation for effectively mitigating metastasis and reducing RISF. This holds great promise for improving clinical outcomes in breast cancer patients undergoing adjuvant radiotherapy.

Triple negative breast cancer (TNBC) has the worst prognosis among breast cancer subtypes. It is characterized by lack of estrogen, progesterone and human epidermal growth factor 2 receptors, and thus, have limited therapeutic options. Autophagy has been found to be correlated with poor prognosis and aggressive behaviour in TNBC. This study aimed to target autophagy in TNBC via a novel approach to inhibit TNBC progression.

Immunoblotting and confocal microscopy were carried out to examine the effect of tumor microenvironmental stressors on autophagy. Cellular proliferation and migration assays were used to test the effect of different autophagy inhibitors and standard chemotherapy alone or in combination. In vivo xenograft mouse model was utilized to assess the effect of autophagy inhibitors alone or in combination with Paclitaxel. High resolution mass spectrometry based proteomic analysis was performed to explore the mechanisms behind chemoresistance in TNBC. Lastly, immunohistochemistry was done to assess the correlation between autophagy related proteins and clinical characteristics in TNBC tissue specimens.

Metabolic stressors were found to induce autophagy in TNBC cell lines. Autophagy initiation inhibitors, SAR405 and MRT68921, showed marked synergy in their anti-proliferative activity in both chemosensitive and chemoresistant TNBC cell models. Paradoxically, positive expression of autophagosome marker LC3 was shown to be associated with better overall survival of TNBC patients.

In this study, a novel combination between different autophagy inhibitors was identified which inhibited tumor cell proliferation in both chemosensitive and chemoresistant TNBC cells and could result in development of a novel treatment modality against TNBC.

In our previous study, we developed a triple-negative breast cancer (TNBC) subtype classification that correlated with the TNBC molecular subclassification. In this study, we aimed to evaluate the predictor variables of this subtype classification on the whole slide and to validate the model's performance by using an external test set. We explored the characteristics of this subtype classification and investigated genomic alterations, including genomic scar signature scores. First, TNBC was classified into the luminal androgen receptor (LAR) and non-luminal androgen receptor (non-LAR) subtypes based on the AR Allred score (≥ 6 and < 6, respectively). Then, the non-LAR subtype was further classified into the lymphocyte-predominant (LP), lymphocyte-intermediate (LI), and lymphocyte-depleted (LD) groups based on stromal tumor-infiltrating lymphocytes (TILs) (< 20%, > 20% but < 60%, and ≥ 60%, respectively). This classification showed fair agreement with the molecular classification in the test set. The LAR subtype was characterized by a high rate of PIK3CA mutation, CD274 (encodes PD-L1) and PDCD1LG2 (encodes PD-L2) deletion, and a low homologous recombination deficiency (HRD) score. The non-LAR LD TIL group was characterized by a high frequency of NOTCH2 and MYC amplification and a high HRD score.

Peptides and proteins encoded by noncanonical open reading frames (ORFs) of circRNAs have recently been recognized to play important roles in disease progression, but the biological functions and mechanisms of these peptides and proteins are largely unknown. Here, we identified a potential coding circular RNA, circTRIM1, that was upregulated in doxorubicin-resistant TNBC cells by intersecting transcriptome and translatome RNA-seq data, and its expression was correlated with clinicopathological characteristics and poor prognosis in patients with TNBC. CircTRIM1 possesses a functional IRES element along with an 810 nt ORF that can be translated into a novel endogenously expressed protein termed TRIM1-269aa. Functionally, we demonstrated that TRIM1-269aa, which is involved in the biological functions of circTRIM1, promoted chemoresistance and metastasis in TNBC cells both in vitro and in vivo. In addition, we found that TRIM1-269aa can be packaged into exosomes and transmitted between TNBC cells. Mechanistically, TRIM1-269aa enhanced the interaction between MARCKS and calmodulin, thus promoting the calmodulin-dependent translocation of MARCKS, which further initiated the activation of the PI3K/AKT/mTOR pathway. Overall, circTRIM1, which encodes TRIM1-269aa, promoted TNBC chemoresistance and metastasis by enhancing MARCKS translocation and PI3K/AKT/mTOR activation. Our investigation has yielded novel insights into the roles of protein-coding circRNAs and supported circTRIM1/TRIM1-269aa as a novel promising prognostic and therapeutic target for patients with TNBC.

Triple Negative Breast Cancer (TNBC) is the most aggressive type of breast cancer (BC). Despite advances in the clinical management of TNBC, recurrence-related mortality remains a challenge. The stem-like phenotype of TNBC plays a significant role in the persistence of minimal disease residue after therapy. Individuals exhibiting stem-like characteristics are particularly prone to inducing malignant relapse accompanied by strong resistance. Therefore, stem-like traits have been broadly proposed as therapeutic vulnerabilities to treat TNBC and reduce recurrence. However, heterogeneity within TNBC often generally restricts the stability of the therapeutic efficacy. To understand the heterogeneity and manage TNBC more precisely, multiple TNBC subtyping categories have been reported, providing the basis for profile-according therapeutic regimens. To provide more insight into targeting stem-like traits to ablate TNBC and reduce recurrence in the context of heterogeneity, this paper reviewed the molecular subtyping of TNBC, identified the consensus subtypes with distinct stem-like phenotypes, characterized the stemness hierarchy of TNBC, outlined the biological models for stem-like TNBC subtypes, summarized the therapeutic vulnerabilities in stem-like traits of the subtypes, and proposed potential therapeutic regimens targeting stem-like characteristics to improve TNBC prognosis.

The basal breast cancer subtype is enriched for triple-negative breast cancer (TNBC) and displays consistent large chromosomal deletions. Here, we characterize evolution and maintenance of chromosome 4p (chr4p) loss in basal breast cancer. Analysis of The Cancer Genome Atlas data shows recurrent deletion of chr4p in basal breast cancer. Phylogenetic analysis of a panel of 23 primary tumor/patient-derived xenograft basal breast cancers reveals early evolution of chr4p deletion. Mechanistically we show that chr4p loss is associated with enhanced proliferation. Gene function studies identify an unknown gene, C4orf19, within chr4p, which suppresses proliferation when overexpressed-a member of the PDCD10-GCKIII kinase module we name PGCKA1. Genome-wide pooled overexpression screens using a barcoded library of human open reading frames identify chromosomal regions, including chr4p, that suppress proliferation when overexpressed in a context-dependent manner, implicating network interactions. Together, these results shed light on the early emergence of complex aneuploid karyotypes involving chr4p and adaptive landscapes shaping breast cancer genomes.

Current guidelines recommendations regarding chemotherapy in small (T1b and T1c), node-negative triple-negative breast cancer (TNBC) differ due to lack of high-quality data. Our study aimed to assess the benefit of adjuvant chemotherapy in patients with T1bN0M0 and T1cN0M0 TNBC.

We obtained data from the Surveillance, Epidemiology, and End Results database for patients with node-negative, T1b/T1c TNBC diagnosed between 2010 and 2020. Logistic regresion models assessed variables associated with chemotherapy administration. We evaluated the effect of chemotherapy on overall survival (OS) and breast cancer specific survival (BCSS) with Kaplan-Meier methods and Cox proportional hazards methods.

We included 11,510 patients: 3,388 with T1b and 8,122 with T1c TNBC. During a median follow-up of 66 months, 305 patients with T1b and 995 with T1c died. After adjusting for clinicopathological, demographic and treatment factors, adjuvant chemotherapy improved OS in T1b TNBC (HR, 0.52; 95% CI, 0.41-0.68 p < 0.001) but did not improve BCSS (HR, 0.70; 95% CI, 0.45-1.07; p = 0.10); the association between chemotherapy and BCSS was not statistically significant in any subgroup. In T1c TNBC, adjuvant chemotherapy improved OS (HR, 0.54; 95% CI, 0.47-0.62; p < 0.001) and BCSS (HR, 0.79; 95% CI, 0.63-0.99; p = 0.043); the benefit of chemotherapy in OS varied by age (Pinteraction=0.024); moreover, the benefit in BCSS was similar in all subgroups.

Our study results support the use of adjuvant chemotherapy in patients with node-negative, T1c TNBC. Patients with node-negative, T1b TNBC had excellent long-term outcomes; furthermore, chemotherapy was not associated with improved BCSS in these patients.

Triple-negative breast cancer (TNBC) is an aggressive subtype with no targeted therapeutics. The luminal androgen receptor (LAR) subtype constitutes 15% of TNBC and is enriched for androgen receptor (AR) and AR target genes. Here, we show that a cohort of TNBC not only expresses AR at a much higher rate (∼80%) but also expresses AR splice variants (AR-SVs) (∼20%), further subclassifying LAR-TNBC. Higher AR and AR-SV expression and corresponding aggressive phenotypes are observed predominantly in specimens obtained from African American women. LAR TNBC specimens are enriched for interferon, Janus kinase (JAK)-signal activator and transducer (STAT), and androgen signaling pathways, which are exclusive to AR-expressing epithelial cancer cells. AR- and AR-SV-expressing TNBC cell proliferation and xenograft and patient-tumor explant growth are inhibited by AR N-terminal domain-binding selective AR degrader or by a JAK inhibitor. Biochemical analysis suggests that STAT1 is an AR coactivator. Collectively, our work identifies pharmacologically targetable TNBC subtypes and identifies growth-promoting interaction between AR and JAK-STAT signaling.

Triple negative breast cancer (TNBC) is regarded as one of the most aggressive forms of breast cancer. Hydroxypropyl-β-cyclodextrin (HP-β-CD) has been used as a therapeutic agent for Niemann-Pick disease Type C (NPC). However, the exact actions and mechanisms of HP-β-CD on TNBC are not fully understood. To examine the influence of HP-β-CD on the proliferation and migration of TNBC cell lines, particularly 4T1 and MDA-MB-231 cells, a range of assays, including MTT, scratch, cell cycle, and clonal formation assays, were performed. Furthermore, the effectiveness of HP-β-CD in the treatment of TNBC was assessed in vivo using a 4T1 tumor-bearing BALB/c mouse model. We demonstrated the anti-proliferation and anti-migration effect of HP-β-CD on TNBC both in vitro and in vivo. High cholesterol diet can attenuate HP-β-CD-inhibited TNBC growth. Mechanistically, HP-β-CD reduced tumor cholesterol levels by increasing ABCA1 and ABCG1-mediated cholesterol reverse transport. HP-β-CD promoted the infiltration of T cells into the tumor microenvironment (TME) and improved exhaustion of CD8+ T cells via reducing immunological checkpoint molecules expression. Additionally, HP-β-CD inhibited the recruitment of tumor associated macrophages to the TME via reducing CCL2-p38MAPK-NF-κB axis. HP-β-CD also inhibited the epithelial mesenchymal transition (EMT) of TNBC cells mediated by the TGF-β signaling pathway. In summary, our study suggests that HP-β-CD effectively inhibited the proliferation and metastasis of TNBC, highlighting HP-β-CD may hold promise as a potential antitumor drug.

This study was conducted to identify the risk causes and predictive models based on the clinical features of patients with breast cancer classified as triple-negative breast cancer (TNBC) and non-triple-negative breast cancer (non-TNBCs) using Korean cancer statistics. A total of 2045 cases that underwent three types of hormone receptor tests were obtained from Korean cancer data in 2016. Research data were analyzed with the software SPSS Ver. 26.0. TNBC and non-TNBCs accounted for 12.4% and 87.6% of the data, respectively. Tubular and lobular tumors occurred most frequently in the external quadrant of the breast (C50.4-C50.5; 43.1%). Compared to non-TNBCs, the incidence of TNBC was the most common in patients under the age of 39 (19.5%), followed by those over the age of 70 (17.3%). Tumors larger than 2 cm accounted for 16.0%, which was higher than the number of tumors smaller than 2 cm. Cases in stage IV cancer represented 21.7% of the data. Additionally, 21.0% of the patients were in the SEER stage of distant metastasis, which was the most prevalent SEER (surveillance, epidemiology, and end outcomes) stage. Neoadjuvant therapy was administered more frequently, with a rate of 24.1%. In the logistic regression and decision-making tree model, the variables that affected TNBC were age, differentiation grade, and neoadjuvant therapy. The predictive accuracies of logistic regression and decision-making tree models were 87.8% and 87.6%, respectively. In a decision-marking tree model, the differentiation grades of TNBC affect neoadjuvant therapy, and neoadjuvant therapy affects the cancer stage. Therefore, in order to promote the health of breast cancer patients, it is urgent to apply an intensive early health check-up program for those in their 40s and 50s with a high prevalence of TNBC. For patients with breast cancer, in TNBC cases, except for poorly differentiated cases, neoadjuvant therapy must be applied first at all differentiation grades. The establishment of a policy system is necessary for the success of this process.

TAB182 participates in DNA damage repair and radio-/chemosensitivity regulation in various tumors, but its role in tumorigenesis and therapeutic resistance in breast cancer remains unclear. In the current paper, we observed that triple-negative Breast Cancer (TNBC), a highly aggressive type of breast cancer, exhibits a lower expression of TAB182. TAB182 knockdown stimulates the proliferation, migration, and invasion of TNBC cells. Our study first obtained RNA-seq data to explore the cellular functions mediated by TAB182 at the genome level in TNBC cells. A transcriptome analysis and in vitro experiments enabled us to identify that TAB182 downregulation drives the enhanced properties of cancer stem-like cells (CSCs) in TNBC cells. Furthermore, TAB182 deletion contributes to the resistance of cells to olaparib or cisplatin, which can be rescued by silencing GLI2, a gene downstream of cancer stemness-related signaling pathways. Our results reveal a novel function of TAB182 as a potential negative regulator of cancer stem-like properties and drug sensitivity in TNBC cells, suggesting that TAB182 may be a tumor suppressor gene and is associated with increased therapeutic benefits for TNBC patients.

Immune checkpoint inhibitors (ICI), pembrolizumab and atezolizumab, were recently approved for treatment-refractory triple-negative breast cancer (TNBC), where those with Programmed death-ligand 1 (PD-L1) positive early-stage disease had improved responses. ICIs are administered systemically in the clinic, however, reaching effective therapeutic dosing is challenging due to severe off-tumor toxicities. As such, intratumoral (IT) injection is increasingly investigated as an alternative delivery approach. However, repeated administration, which sometimes is invasive, is required due to rapid drug clearance from the tumor caused by increased interstitial fluid pressure. To minimize off-target drug biodistribution, we developed the nanofluidic drug-eluting seed (NDES) platform for sustained intratumoral release of therapeutic via molecular diffusion. Here we compared drug biodistribution between the NDES, intraperitoneal (IP) and intratumoral (IT) injection using fluorescently labeled PD-L1 monoclonal antibody (αPD-L1). We used two syngeneic TNBC murine models, EMT6 and 4T1, that differ in PD-L1 expression, immunogenicity, and transport phenotype. We investigated on-target (tumor) and off-target distribution using different treatment approaches. As radiotherapy is increasingly used in combination with immunotherapy, we sought to investigate its effect on αPD-L1 tumor accumulation and systemic distribution. The NDES-treated cohort displayed sustained levels of αPD-L1 in the tumor over the study period of 14 days with significantly lower off-target organ distribution, compared to the IP or IT injection. However, we observed differences in the biodistribution of αPD-L1 across tumor models and with radiation pretreatment. Thus, we sought to extensively characterize the tumor properties via histological analysis, diffusion evaluation and nanoparticles contrast-enhanced CT. Overall, we demonstrate that ICI delivery via NDES is an effective method for sustained on-target tumor delivery across tumor models and combination treatments.