Exploring the multifaceted impact of lanthanides on physiological pathways in human breast cancer cells

Lanthanum (La) and cerium (Ce), rare earth elements with physical properties similar to calcium (Ca), are generally considered non-toxic when used appropriately. However, their ions possess anti-tumor capabilities. This investigation explores the potential applications and mechanisms of LaCl3 or CeCl3 treatment in triple-negative breast cancer (TNBC) cell lines. TNBC, characterized by the absence of estrogen receptor (ERα), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER-2) expression, is prone to early metastasis and resistant to hormone therapy. Our results demonstrate that La/Ce treatment reduces cell growth, and when combined with cisplatin, it synergistically inhibits cell growth and the PI3K/AKT pathway. La and Ce induce oxidative stress by disrupting mitochondrial function, leading to protein oxidation. Additionally, they interfere with protein homeostasis and induce nucleolar stress. Furthermore, disturbance in F-actin web formation impairs cell migration. This study delves into the mechanism by which calcium-like elements La and Ce inhibit breast cancer cell growth, shedding light on their interference in mitochondrial function, protein homeostasis, and cytoskeleton assembly.

Single-cell RNA-seq reveals the metabolic status of immune cells response to immunotherapy in triple-negative breast cancer

Immune checkpoint blockade (ICB) therapy offers promise in the treatment of triple-negative breast cancer (TNBC); however, its limited efficacy in certain TNBC patients poses a challenge. In this study, we elucidated the metabolic mechanism at 'sub-subtype' resolution underlying the non-response to ICB therapy in TNBC. Here, an analytic pipeline was developed to reveal the metabolic heterogeneity, which is correlated with the ICB outcomes, within each immune cell subtype. First, we identified metabolic 'sub-subtypes' within certain cell subtypes, predominantly T cell subsets, which are enriched in ICB non-responders and named as non-responder-enriched (NR-E) clusters. Notably, most of NR-E T metabolic cells exhibit globally higher metabolic activities compared to other cells within the same individual subtype. Further, we investigated the extra-cellular signals that trigger the metabolic status of NR-E T cells. In detail, the prediction of cell-to-cell communication indicated that NR-E T cells are regulated by plasmatic dendritic cells (pDCs) through TNFSF9, as well as by macrophages expressing SIGLEC9. In addition, we also validate the communication between TNFSF9+ pDCs and NR-E T cells utilizing deconvolution of spatial transcriptomics analysis. In summary, our research identified specific metabolic 'sub-subtypes' associated with ICB non-response and uncovered the mechanisms of their regulation in TNBC. And the proposed analytical pipeline can be used to examine metabolic heterogeneity within cell types that correlate with diverse phenotypes.

Investigating the Immunogenic Cell Death-Dependent Subtypes and Prognostic Signature of Triple-Negative Breast Cancer

Recently, immunotherapy has emerged as a promising and effective method for treating triple-negative breast cancer (TNBC). However, challenges still persist. Immunogenic cell death (ICD) is considered a prospective treatment and potential combinational treatment strategy as it induces an anti-tumor immune response by presenting the antigenic epitopes of dead cells. Nevertheless, the ICD process in TNBC and its impact on disease progression and the response to immunotherapy are not well understood. In this study, we observed dysregulation of the ICD process and verified the altered expression of prognostic ICD genes in TNBC through quantitative real-time polymerase chain reaction (qRT-PCR) analysis. To investigate the potential role of the ICD process in TNBC progression, we determined the ICD-dependent subtypes, and two were identified. Analysis of their distinct tumor immune microenvironment (TIME) and cancer hallmark features revealed that Cluster 1 and 2 corresponded to the immune "cold" and "hot" phenotypes, respectively. In addition, we constructed the prognostic signature ICD score of TNBC patients and demonstrated its clinical independence and generalizability. The ICD score could also serve as a potential biomarker for immune checkpoint blockade and may aid in the identification of targeted effective agents for individualized clinical strategies.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43657-023-00133-x.

LC-MS/MS platform-based serum untargeted screening reveals the diagnostic biomarker panel and molecular mechanism of breast cancer

BACKGROUND

Breast cancer (BC), the most common form of malignant cancer affecting women worldwide, was characterized by heterogeneous metabolic disorder and lack of effective biomarkers for diagnosis. The purpose of this study is to search for reliable metabolite biomarkers of BC as well as triple-negative breast cancer (TNBC) using serum metabolomics approach.

METHODS

In this study, an untargeted metabolomics technique based on ultra-high performance liquid chromatography combined with mass spectrometry (UHPLC-MS) was utilized to investigate the differences in serum metabolic profile between the BC group (n = 53) and non-BC group (n = 57), as well as between TNBC patients (n = 23) and non-TNBC subjects (n = 30). The multivariate data analysis, determination of the fold change and the Mann-Whitney U test were used to screen out the differential metabolites. Additionally, machine learning methods including receiver operating curve analysis and logistic regression analysis were conducted to establish diagnostic biomarker panels.

RESULTS

There were 36 metabolites found to be significantly different between BC and non-BC groups, and 12 metabolites discovered to be significantly different between TNBC and non-TNBC patients. Results also showed that four metabolites, including N-acetyl-D-tryptophan, 2-arachidonoylglycerol, pipecolic acid and oxoglutaric acid, were considered as vital biomarkers for the diagnosis of BC and non-BC with an area under the curve (AUC) of 0.995. Another two-metabolite panel of N-acetyl-D-tryptophan and 2-arachidonoylglycerol was discovered to discriminate TNBC from non-TNBC and produced an AUC of 0.965.

CONCLUSION

This study demonstrated that serum metabolomics can be used to identify BC specifically and identified promising serum metabolic markers for TNBC diagnosis.

Fluvastatin prevents lung metastasis in triple-negative breast cancer by triggering autophagy via the RhoB/PI3K/mTOR pathway

Triple-negative breast cancer is more common among younger than older women and is associated with the poorest survival outcomes of all breast cancer types. Fluvastatin inhibits tumour progression and induces the autophagy of breast cancer cells; however, the role of autophagy in fluvastatin-induced inhibition of breast cancer metastasis is unknown. Therefore, this study aimed to determine this mechanism. The effect of fluvastatin on human hormone receptor-negative breast cancer cells was evaluated in vitro via migration and wound healing assays, western blotting, and morphological measurements, as well as in vivo using a mouse xenograft model. Chloroquine, a prophylactic medication used to prevent malaria in humans was used as an autophagy inhibitor. We found that fluvastatin administration effectively prevented the migration/invasion of triple-negative breast cancer cells, an effect that was largely dependent on the induction of autophagy. Administration of the autophagy inhibitor chloroquine prevented the fluvastatin-induced suppression of lung metastasis in the nude mouse model. Furthermore, fluvastatin increased Ras homolog family member B (RhoB) expression, and the autophagy and anti-metastatic activity induced by fluvastatin were predominantly dependent on the regulation of RhoB through the protein kinase B-mammalian target of rapamycin (Akt-mTOR) signaling pathway. These results suggest that fluvastatin inhibits the metastasis of triple-negative breast cancer cells by modulating autophagy via the up regulation of RhoB through the AKT-mTOR signaling pathway. Fluvastatin may be a promising therapeutic option for patients with triple-negative breast cancer.

SHC4 orchestrates β-catenin pathway-mediated metastasis in triple-negative breast cancer by promoting Src kinase autophosphorylation

Triple-negative breast cancer (TNBC) is highly aggressive and metastatic, and has the poorest prognosis among all breast cancer subtypes. Activated β-catenin is enriched in TNBC and involved in Wnt signaling-independent metastasis. However, the underlying mechanisms of β-catenin activation in TNBC remain unknown. Here, we found that SHC4 was upregulated in TNBC and high SHC4 expression was significantly correlated with poor outcomes. Overexpression of SHC4 promoted TNBC aggressiveness in vitro and facilitated TNBC metastasis in vivo. Mechanistically, SHC4 interacted with Src and maintained its autophosphorylated activation, which activated β-catenin independent of Wnt signaling, and finally upregulated the transcription and expression of its downstream genes CD44 and MMP7. Furthermore, we determined that the PxPPxPxxxPxxP sequence on CH2 domain of SHC4 was critical for SHC4-Src binding and Src kinase activation. Overall, our results revealed the mechanism of β-catenin activation independent of Wnt signaling in TNBC, which was driven by SHC4-induced Src autophosphorylation, suggesting that SHC4 might be a potential prognostic marker and therapeutic target in TNBC.

A novel axis of circKIF4A-miR-637-STAT3 promotes brain metastasis in triple-negative breast cancer

Among patients with triple-negative breast cancer (TNBC), distant metastasis is the leading cause of death. Our previous studies have shown that TNBC progression is greatly facilitated by circKIF4A, but uncertainty remains regarding its role in TNBC brain metastasis and the molecular mechanism. In this study, we found notable upregulation of circKIF4A in TNBC cell lines and brain metastases. Inhibition of circKIF4A impaired the ability of TNBC to proliferate, migrate, and cause brain metastasis. Luciferase reporter assays confirmed that circKIF4A competed for binding to miR-637 with STAT3 3' UTR. Western blot analysis revealed that inhibition of circKIF4A decreased STAT3 and p62 expression, while increased the LC3B-II/LC3B-I ratio and the expression of Beclin, indicating that downregulation of circKIF4A induced autophagy by competing with STAT3 for binding to miR-637. By employing a competitive endogenous RNA (ceRNA) mechanism, the circKIF4A-miR-637-STAT3 axis coordinates brain metastasis in TNBC. circKIF4A can therefore be used as a prognostic biomarker for brain metastasis in TNBC and as a therapeutic target.

Advances in Monoclonal Antibody Therapies for Triple-Negative Breast Cancer: Immunotherapeutic and Targeted Strategies

Triple-negative breast cancer (TNBC) presents considerable obstacles because of its highly aggressive characteristics and limited availability of specific therapeutic interventions. The utilization of monoclonal antibody (mAb)-based immunotherapy is a viable approach to tackle these difficulties. This review aims to examine the present state of mAb-based immunotherapy in TNBC, focusing on the underlying mechanisms of action, clinical applications, and existing challenges. The effectiveness of mAbs in reducing tumor development, regulating immune responses, and changing the tumor microenvironment has been demonstrated in many clinical investigations. The challenges encompass several aspects such as the discovery of biomarkers, understanding resistance mechanisms, managing toxicity, considering costs, and ensuring accessibility. The future is poised to bring forth significant advancements in the field of biomedicine, particularly in the areas of new mAbs, personalized medicine, and precision immunotherapy. In conclusion, mAb-based immunotherapy has promise in revolutionizing the treatment of TNBC, hence providing a possible avenue for enhanced patient outcomes and quality of life.

Fbxw7 suppresses carcinogenesis and stemness in triple-negative breast cancer through CHD4 degradation and Wnt/β-catenin pathway inhibition

BACKGROUND

Cancer stem cells (CSCs) are a small population of cells in tumor tissues that can drive tumor initiation and promote tumor progression. A small number of previous studies indirectly mentioned the role of F-box and WD repeat domain-containing 7 (FBXW7) as a tumor suppressor in Triple-negative breast cancer (TNBC). However, few studies have focused on the function of FBXW7 in cancer stemness in TNBC and the related mechanism.

METHODS

We detected FBXW7 by immunohistochemistry (IHC) in 80 TNBC patients. FBXW7 knockdown and overexpression in MD-MBA-231 and HCC1937 cell models were constructed. The effect of FBXW7 on malignant phenotype and stemness was assessed by colony assays, flow cytometry, transwell assays, western blot, and sphere formation assays. Immunoprecipitation-Mass Spectrometry (IP-MS) and ubiquitination experiments were used to find and verify potential downstream substrate proteins of FBXW7. Animal experiments were constructed to examine the effect of FBXW7 on tumorigenic potential and cancer stemness of TNBC cells in vivo.

RESULTS

The results showed that FBXW7 was expressed at low levels in TNBC tissues and positively correlated with prognosis of TNBC patients. In vitro, FBXW7 significantly inhibited colony formation, cell cycle progression, cell migration, EMT process, cancer stemness and promotes apoptosis. Further experiments confirmed that chromodomain-helicase-DNA-binding protein 4 (CHD4) is a novel downstream target of FBXW7 and is downregulated by FBXW7 via proteasomal degradation. Moreover, CHD4 could promote the nuclear translocation of β-catenin and reverse the inhibitory effect of FBXW7 on β-catenin, and ultimately activate the Wnt/β-catenin pathway. Rescue experiments confirmed that the FBXW7-CHD4-Wnt/β-catenin axis was involved in regulating the maintenance of CSC in TNBC cells. In animal experiments, FBXW7 reduced CSC marker expression and suppressed TNBC cell tumorigenesis in vivo.

CONCLUSIONS

Taken together, these results highlight that FBXW7 degrades CHD4 protein through ubiquitination, thereby blocking the activation of the Wnt/β-catenin pathway to inhibit the stemness of TNBC cells. Thus, targeting FBXW7 may be a promising strategy for therapeutic intervention against TNBC.

Imprint Cytology of Tall Cell Carcinoma with Reversed Polarity of the Breast: A Case Report

INTRODUCTION

Tall cell carcinoma with reversed polarity (TCCRP) is a rare histologic subtype of breast cancer that was newly categorized in 2020. TCCRP is a relatively novel tumor, and there are no detailed reports about its cellular morphology. We were able to obtain imprint cytological specimens from fresh TCCRP tissue, and we provide our detailed observations.

CASE PRESENTATION

The patient was a 73-year-old Japanese female with a 15-mm mass in her right breast. After invasive breast carcinoma was diagnosed based on a core needle biopsy, a lumpectomy was performed. The pathological examination revealed TCCRP, and Sanger sequencing detected IDH2 p.R172M hotspot mutation, which is characteristic of TCCRP. Soon after the surgery, the lumpectomy specimen was sliced before fixation for use in a clinical trial, and imprint cytological materials were obtained from the tumor's cut surface. Cytologically, the tumor showed papillary-like cell clusters and isolated cells with moderate cellularity. Neoplastic cell aggregates and clusters with thick vascular cores as the axis or with delicate fibrovascular stroma were observed. Most of the neoplastic cells were cuboidal-to-columnar in shape, with mildly to moderately irregularly shaped blunt nuclei. Some intranuclear cytoplasmic inclusions and nuclear grooves were present, resembling the nuclear findings of papillary thyroid carcinoma. The most characteristic finding was the columnar cell clusters with apically located nuclei, giving the impression of reversed polarity.

CONCLUSION

We described cytological findings in TCCRP, a newly classified rare mammary tumor. Most of the characteristic histologic findings were also observed in imprint cytological specimens. Further studies on practical specimens such as fine-needle aspiration are needed for clinical application.

Understanding the Interplay of CAR-NK Cells and Triple-Negative Breast Cancer: Insights from Computational Modeling

Chimeric antigen receptor (CAR)-engineered natural killer (NK) cells have recently emerged as a promising and safe alternative to CAR-T cells for targeting solid tumors. In the case of triple-negative breast cancer (TNBC), traditional cancer treatments and common immunotherapies have shown limited effectiveness. However, CAR-NK cells have been successfully employed to target epidermal growth factor receptor (EGFR) on TNBC cells, thereby enhancing the efficacy of immunotherapy. The effectiveness of CAR-NK-based immunotherapy is influenced by various factors, including the vaccination dose, vaccination pattern, and tumor immunosuppressive factors in the microenvironment. To gain insights into the dynamics and effects of CAR-NK-based immunotherapy, we propose a computational model based on experimental data and immunological theories. This model integrates an individual-based model that describes the interplay between the tumor and the immune system, along with an ordinary differential equation model that captures the variation of inflammatory cytokines. Computational results obtained from the proposed model shed light on the conditions necessary for initiating an effective anti-tumor response. Furthermore, global sensitivity analysis highlights the issue of low persistence of CAR-NK cells in vivo, which poses a significant challenge for the successful clinical application of these cells. Leveraging the model, we identify the optimal vaccination time, vaccination dose, and time interval between injections for maximizing therapeutic outcomes.

LINC00571 drives tricarboxylic acid cycle metabolism in triple-negative breast cancer through HNRNPK/ILF2/IDH2 axis

BACKGROUND

Triple-negative breast cancer is a complex breast malignancy subtype characterized by poor prognosis. The pursuit of effective therapeutic approaches for this subtype is considerably challenging. Notably, recent research has illuminated the key role of the tricarboxylic acid cycle in cancer metabolism and the complex landscape of tumor development. Concurrently, an emerging body of evidence underscores the noteworthy role that long non-coding RNAs play in the trajectory of breast cancer development. Despite this growing recognition, the exploration of whether long non-coding RNAs can influence breast cancer progression by modulating the tricarboxylic acid cycle has been limited. Moreover, the underlying mechanisms orchestrating these interactions have not been identified.

METHODS

The expression levels of LINC00571 and IDH2 were determined through the analysis of the public TCGA dataset, transcriptome sequencing, qRT‒PCR, and Western blotting. The distribution of LINC00571 was assessed using RNA fluorescence in situ hybridization. Alterations in biological effects were evaluated using CCK-8, colony formation, EdU, cell cycle, and apoptosis assays and a tumor xenograft model. To elucidate the interaction between LINC00571, HNRNPK, and ILF2, RNA pull-down, mass spectrometry, coimmunoprecipitation, and RNA immunoprecipitation assays were performed. The impacts of LINC00571 and IDH2 on tricarboxylic acid cycle metabolites were investigated through measurements of the oxygen consumption rate and metabolite levels.

RESULTS

This study revealed the complex interactions between a novel long non-coding RNA (LINC00571) and tricarboxylic acid cycle metabolism. We validated the tumor-promoting role of LINC00571. Mechanistically, LINC00571 facilitated the interaction between HNRNPK and ILF2, leading to reduced ubiquitination and degradation of ILF2, thereby stabilizing its expression. Furthermore, ILF2 acted as a transcription factor to enhance the expression of its downstream target gene IDH2.

CONCLUSIONS

Our study revealed that the LINC00571/HNRNPK/ILF2/IDH2 axis promoted the progression of triple-negative breast cancer by regulating tricarboxylic acid cycle metabolites. This discovery provides a novel theoretical foundation and new potential targets for the clinical treatment of triple-negative breast cancer.

Digital image analysis and machine learning-assisted prediction of neoadjuvant chemotherapy response in triple-negative breast cancer

BACKGROUND

Pathological complete response (pCR) is associated with favorable prognosis in patients with triple-negative breast cancer (TNBC). However, only 30-40% of TNBC patients treated with neoadjuvant chemotherapy (NAC) show pCR, while the remaining 60-70% show residual disease (RD). The role of the tumor microenvironment in NAC response in patients with TNBC remains unclear. In this study, we developed a machine learning-based two-step pipeline to distinguish between various histological components in hematoxylin and eosin (H&E)-stained whole slide images (WSIs) of TNBC tissue biopsies and to identify histological features that can predict NAC response.

METHODS

H&E-stained WSIs of treatment-naïve biopsies from 85 patients (51 with pCR and 34 with RD) of the model development cohort and 79 patients (41 with pCR and 38 with RD) of the validation cohort were separated through a stratified eightfold cross-validation strategy for the first step and leave-one-out cross-validation strategy for the second step. A tile-level histology label prediction pipeline and four machine-learning classifiers were used to analyze 468,043 tiles of WSIs. The best-trained classifier used 55 texture features from each tile to produce a probability profile during testing. The predicted histology classes were used to generate a histology classification map of the spatial distributions of different tissue regions. A patient-level NAC response prediction pipeline was trained with features derived from paired histology classification maps. The top graph-based features capturing the relevant spatial information across the different histological classes were provided to the radial basis function kernel support vector machine (rbfSVM) classifier for NAC treatment response prediction.

RESULTS

The tile-level prediction pipeline achieved 86.72% accuracy for histology class classification, while the patient-level pipeline achieved 83.53% NAC response (pCR vs. RD) prediction accuracy of the model development cohort. The model was validated with an independent cohort with tile histology validation accuracy of 83.59% and NAC prediction accuracy of 81.01%. The histological class pairs with the strongest NAC response predictive ability were tumor and tumor tumor-infiltrating lymphocytes for pCR and microvessel density and polyploid giant cancer cells for RD.

CONCLUSION

Our machine learning pipeline can robustly identify clinically relevant histological classes that predict NAC response in TNBC patients and may help guide patient selection for NAC treatment.

Patient-specific signaling signatures predict optimal therapeutic combinations for triple negative breast cancer

Triple negative breast cancer (TNBC) is a heterogeneous group of tumors which lack estrogen receptor, progesterone receptor, and HER2 expression. Targeted therapies have limited success in treating TNBC, thus a strategy enabling effective targeted combinations is an unmet need. To tackle these challenges and discover individualized targeted combination therapies for TNBC, we integrated phosphoproteomic analysis of altered signaling networks with patient-specific signaling signature (PaSSS) analysis using an information-theoretic, thermodynamic-based approach. Using this method on a large number of TNBC patient-derived tumors (PDX), we were able to thoroughly characterize each PDX by computing a patient-specific set of unbalanced signaling processes and assigning a personalized therapy based on them. We discovered that each tumor has an average of two separate processes, and that, consistent with prior research, EGFR is a major core target in at least one of them in half of the tumors analyzed. However, anti-EGFR monotherapies were predicted to be ineffective, thus we developed personalized combination treatments based on PaSSS. These were predicted to induce anti-EGFR responses or to be used to develop an alternative therapy if EGFR was not present.In-vivo experimental validation of the predicted therapy showed that PaSSS predictions were more accurate than other therapies. Thus, we suggest that a detailed identification of molecular imbalances is necessary to tailor therapy for each TNBC. In summary, we propose a new strategy to design personalized therapy for TNBC using pY proteomics and PaSSS analysis. This method can be applied to different cancer types to improve response to the biomarker-based treatment.

Circulating blood biomarkers correlated with the prognosis of advanced triple negative breast cancer

BACKGROUND

Immune checkpoint inhibitors (ICIs) can improve survivals of metastatic triple negative breast cancer (mTNBC); however, we still seek circulating blood biomarkers to predict the efficacy of ICIs.

MATERIALS AND METHODS

In this study, we analyzed the data of ICIs treated mTNBC collected in Anhui Medical University affiliated hospitals from 2018 to 2023. The counts of lymphocytes, monocytes, platelets, and ratio indexes (NLR, MLR, PLR) in peripheral blood were investigated via the Kaplan-Meier curves and the Cox proportional-hazards model.

RESULTS

The total of 50 mTNBC patients were treated with ICIs. High level of peripheral lymphocytes and low level of NLR and MLR at baseline and post the first cycle of ICIs play the predictable role of immunotherapies. Lymphocytes counts (HR = 0.280; 95% CI: 0.095-0.823; p = 0.021) and NLR (HR = 1.150; 95% CI: 1.052-1.257; p = 0.002) are significantly correlated with overall survival. High NLR also increases the risk of disease progression (HR = 2.189; 95% CI:1.085-4.414; p = 0.029). When NLR at baseline ≥ 2.75, the hazard of death (HR = 2.575; 95% CI:1.217-5.447; p = 0.013) and disease progression (HR = 2.189; 95% CI: 1.085-4.414; p = 0.029) significantly rise. HER-2 expression and anti-tumor therapy lines are statistically correlated with survivals.

CONCLUSIONS

Before the initiation of ICIs, enriched peripheral lymphocytes and poor neutrophils and NLR contribute to the prediction of survivals.

Long-term outcomes of young, node-negative, chemotherapy-naïve, triple-negative breast cancer patients according to BRCA1 status

BACKGROUND

Due to the abundant usage of chemotherapy in young triple-negative breast cancer (TNBC) patients, the unbiased prognostic value of BRCA1-related biomarkers in this population remains unclear. In addition, whether BRCA1-related biomarkers modify the well-established prognostic value of stromal tumor-infiltrating lymphocytes (sTILs) is unknown. This study aimed to compare the outcomes of young, node-negative, chemotherapy-naïve TNBC patients according to BRCA1 status, taking sTILs into account.

METHODS

We included 485 Dutch women diagnosed with node-negative TNBC under age 40 between 1989 and 2000. During this period, these women were considered low-risk and did not receive chemotherapy. BRCA1 status, including pathogenic germline BRCA1 mutation (gBRCA1m), somatic BRCA1 mutation (sBRCA1m), and tumor BRCA1 promoter methylation (BRCA1-PM), was assessed using DNA from formalin-fixed paraffin-embedded tissue. sTILs were assessed according to the international guideline. Patients' outcomes were compared using Cox regression and competing risk models.

RESULTS

Among the 399 patients with BRCA1 status, 26.3% had a gBRCA1m, 5.3% had a sBRCA1m, 36.6% had tumor BRCA1-PM, and 31.8% had BRCA1-non-altered tumors. Compared to BRCA1-non-alteration, gBRCA1m was associated with worse overall survival (OS) from the fourth year after diagnosis (adjusted HR, 2.11; 95% CI, 1.18-3.75), and this association attenuated after adjustment for second primary tumors. Every 10% sTIL increment was associated with 16% higher OS (adjusted HR, 0.84; 95% CI, 0.78-0.90) in gBRCA1m, sBRCA1m, or BRCA1-non-altered patients and 31% higher OS in tumor BRCA1-PM patients. Among the 66 patients with tumor BRCA1-PM and ≥ 50% sTILs, we observed excellent 15-year OS (97.0%; 95% CI, 92.9-100%). Conversely, among the 61 patients with gBRCA1m and < 50% sTILs, we observed poor 15-year OS (50.8%; 95% CI, 39.7-65.0%). Furthermore, gBRCA1m was associated with higher (adjusted subdistribution HR, 4.04; 95% CI, 2.29-7.13) and tumor BRCA1-PM with lower (adjusted subdistribution HR, 0.42; 95% CI, 0.19-0.95) incidence of second primary tumors, compared to BRCA1-non-alteration.

CONCLUSIONS

Although both gBRCA1m and tumor BRCA1-PM alter BRCA1 gene transcription, they are associated with different outcomes in young, node-negative, chemotherapy-naïve TNBC patients. By combining sTILs and BRCA1 status for risk classification, we were able to identify potential subgroups in this population to intensify and optimize adjuvant treatment.

Adoptive cell transfer therapy with ex vivo primed peripheral lymphocytes in combination with anti-PDL1 therapy effectively inhibits triple-negative breast cancer growth and metastasis

BACKGROUND

Adoptive cell transfer cancer immunotherapy holds promise for treating disseminated disease, yet generating sufficient numbers of lymphocytes with anti-cancer activity against diverse specificities remains a major challenge. We recently developed a novel procedure (ALECSAT) for selecting, expanding and maturating polyclonal lymphocytes from peripheral blood with the capacity to target malignant cells.

METHODS

Immunodeficient mice were challenged with triple-negative breast cancer cell lines or patient-derived xenografts (PDX) and treated with allogeneic or autologous ALECSAT cells with and without anti-PDL1 therapy to assess the capacity of ALECSAT cells to inhibit primary tumor growth and metastasis.

RESULTS

ALECSAT mono therapy inhibited metastasis, but did not inhibit primary tumor growth or prolong survival of tumor-bearing mice. In contrast, combined ALECSAT and anti-PDL1 therapy significantly inhibited primary tumor growth, nearly completely blocked metastasis, and prolonged survival of tumor-bearing mice.

CONCLUSIONS

Combined ALECSAT and anti-PDL1 therapy results in favorable anti-cancer responses in both cell line-derived xenograft and autologous PDX models of advanced triple-negative breast cancer.

A real-world study of the effectiveness and safety of apatinib-based regimens in metastatic triple-negative breast cancer

PURPOSE

This investigation sought to examine the efficacy and safety of low-dose apatinib used alongside chemotherapy in the clinical management of patients with metastatic triple-negative breast cancer (TNBC) within a real-world setting, whilst comparing the outcomes with those treated solely with chemotherapy.

METHODS

This case series study analyzed clinical data and treatment outcomes of 163 patients with metastatic TNBC who underwent rescue treatment at the Medical Oncology Department of Clinical Oncology, Fujian Cancer Hospital, School of Fujian Medical University, China, between October 2011 and January 2023. All the patients underwent rescue treatment with either chemotherapy alone or apatinib (250 mg/day) combined with chemotherapy. The study's primary outcome was progression-free survival (PFS), whereas the secondary outcomes included overall survival (OS), objective response rate (ORR), disease control rate (DCR), and safety profiles.

RESULTS

The study was designed to compare two groups [1]. Out of the 163 TNBC patients who participated in the study, 107 individuals (65.6%) received treatment based on chemotherapy, whereas 56 patients (34.4%) were given treatment based on a combination of low-dose apatinib (250 mg/day) and other treatments, including chemotherapy. After propensity score matching (PSM), the objective response rate (ORR) and disease control rate (DCR) of patients with advanced triple-negative breast cancer (TNBC) who received apatinib-based treatment were 50.0 and 90.0%, respectively, while they were 6.7 and 20.0%, respectively, for the chemotherapy-based group (P < 0.001). The group that received apatinib-based treatment showed superior results in both PFS and OS compared to the group that received chemotherapy. The median PFS and OS for the apatinib-based group were 7.8 and 20.3 months, respectively, while they were only 2.2 months and 9.0 months, respectively, for the chemotherapy-based group (P < 0.001) [2]. Patients who were administered combo therapies, including PD-1 inhibitors, were excluded. In total, 97 patients received chemotherapy alone, while 34 patients were treated with apatinib in combination with chemotherapy. After propensity score matching (PSM), the ORR and DCR for the total group who received combo therapies were 44.4 and 81.5%, respectively, while they were 11.1 and 22.2%, respectively, for the chemotherapy alone group (P < 0.001). The group receiving both apatinib and chemotherapy displayed notable advantages over the group solely receiving chemotherapy in regards to PFS and OS for the entirety of the population. The PFS was found to be 7.8 months in comparison to 2.1 months (P < 0.001) and the OS was 21.1 months in contrast to 9.0 months (P < 0.001). Apatinib combined with chemotherapy induced grade 3/4 hematological toxicities, including neutropenia (8.8%) and thrombocytopenia (2.9%). Additionally, non-hematological toxicities were commonly observed, such as Hand-foot syndrome (35.3%), proteinuria (26.5%), hypertension (61.8%), higher alanine aminotransferase levels (26.5%), and fatigue (35.3%). The most frequent non-hematological grade 3/4 toxicities were Hand-foot syndrome (2.9%) and hypertension (5.9%). The study did not report any fatal adverse effects.

CONCLUSIONS

The combination of low-dose apatinib with chemotherapy has proven to be more effective than chemotherapy alone in treating metastatic triple-negative breast cancer (TNBC). Additionally, the occurrence of grade 3/4 non-hematologic toxicities was significantly lower compared to the recommended dose of apatinib.

Targeting tumor-stromal interactions in triple-negative breast cancer using a human vascularized micro-tumor model

Triple-negative breast cancer (TNBC) is highly aggressive with limited available treatments. Stromal cells in the tumor microenvironment (TME) are crucial in TNBC progression; however, understanding the molecular basis of stromal cell activation and tumor-stromal crosstalk in TNBC is limited. To investigate therapeutic targets in the TNBC stromal niche, we used an advanced human in vitro microphysiological system called the vascularized micro-tumor (VMT). Using single-cell RNA sequencing, we revealed that normal breast tissue stromal cells activate neoplastic signaling pathways in the TNBC TME. By comparing interactions in VMTs with clinical data, we identified therapeutic targets at the tumor-stromal interface with potential clinical significance. Combining treatments targeting Tie2 signaling with paclitaxel resulted in vessel normalization and increased efficacy of paclitaxel in the TNBC VMT. Dual inhibition of HER3 and Akt also showed efficacy against TNBC. These data demonstrate the potential of inducing a favorable TME as a targeted therapeutic approach in TNBC.

Compartmental Syndecan-1 (CD138) expression as a novel prognostic marker in triple-negative metaplastic breast cancer

BACKGROUND

Metaplastic breast cancer (MpBC) is rare, aggressive, and mostly triple-negative (TN) subtype of BC. We aimed to investigate the potential prognostic significance of Syndecan-1 (SDC1/CD138) expression in this unique tumor.

METHODS

Archived charts of 50 TNBC patients [21 MpBC and 29 invasive ductal carcinoma (IDC)] were retrospectively evaluated. Corresponding paraffin blocks were used for immunohistochemical (IHC) staining of SDC1. Compartmental (epithelial membranous, stromal, and cytoplasmic) staining scores were expressed in quartiles (Q) and correlated with disease-free survival (DFS) and overall survival (OS).

RESULTS

The median follow-up period was 54.6 months (range: 2.2-112.7). MpBC patients showed significantly worse DFS and OS than IDC (p = 0.007 and 0.004, respectively). MpBC demonstrated significantly higher Q4 stromal and membranous SDC1 compared to IDC (p = 0.016 and 0.021, respectively), whereas IDC exhibited significantly higher cytoplasmic Q4 SDC1 than MpBC (p = 0.015). Stromal Q4 SDC1 expression was found to be an independent factor associated with MpBC relative to IDC (OR: 6.7, 95% CI: 1.24-36.90; p = 0.028). Stromal Q4 SDC1 expression was also an independent prognostic parameter for worse DFS and OS compared to Q1-3 in the whole cohort (HR: 4.2, 95% CI: 1.6-10.5; p = 0.003 and HR: 5.8; 95% CI: 2.2-15.3; p < 0.001, respectively). In MpBC, cytoplasmic Q1-3 SDC1 expression was an independent prognostic indicator for worse OS compared with their IDC counterparts (HR: 2.837, 95% CI: 1.048-7.682; p = 0.04).

CONCLUSION

This study suggests, for the first time, that differential expression and localization of SDC1 may contribute to the pathogenesis and prognosis of TN-MpBC. Therefore, targeting SDC1 (CD138) could emerge as a novel therapeutic approach for this devastating disease.

Eribulin promotes proliferation of CD8+ T cells and potentiates T cell-mediated anti-tumor activity against triple-negative breast cancer cells

PURPOSE

Chemotherapeutic agents exert immunomodulatory effects on triple-negative breast cancer (TNBC) cells and immune cells. Eribulin favorably affects the immunological status of patients with breast cancer. However, the effects of eribulin on the immune cells remain unexplored. The aim of this study was to investigate the effects of eribulin on immune cells.

METHODS

Peripheral blood mononuclear cells (PBMCs) from healthy donors and mouse splenocytes were stimulated with anti-CD3 and anti-CD28 antibodies. The effects of eribulin and paclitaxel on cell proliferation and differentiation status were analyzed using flow cytometry. RNA sequencing was performed to assess alterations in gene expression in CD8+ T cells following eribulin and paclitaxel treatment. Using TNBC cell lines (MDA-MB-231, Hs578T, and MDA-MB-157), the anti-tumor activity of CD3/CD28-stimulated T cells combined with eribulin or paclitaxel was evaluated.

RESULTS

Eribulin did not affect CD3/CD28-stimulated PBMCs proliferation. However, eribulin significantly decreased the CD4/CD8 ratio in T cells, indicating that eribulin facilitates CD8+ T cell proliferation. Furthermore, eribulin significantly increased the frequency of less differentiated CD45RA+, CCR7+, and TCF1+ subsets of CD8+ T cells. RNA sequencing revealed that eribulin enhanced the expression of gene sets related to cell proliferation and immune responses. Moreover, eribulin augmented the anti-tumor effects of CD3/CD28-stimulated T cells against TNBC cells. These results were not observed in experiments using paclitaxel.

CONCLUSIONS

Eribulin promoted CD8+ T cell proliferation, repressed effector T cell differentiation, and harnessed T cell-mediated anti-tumor effects. These mechanisms may be one of the cues that eribulin can improve the immunological status of tumor-bearing hosts.

Programmed Co-delivery of tamoxifen and docetaxel using lipid-coated mesoporous silica nanoparticles for overcoming CYP3A4-mediated resistance in triple-negative breast cancer treatment

PURPOSE

This study aims to revolutionize the treatment of aggressive triple-negative breast cancer (TNBC), notorious for its resistance to standard therapies. By ingeniously combining Tamoxifen (TMX) and Docetaxel (DTX) within a lipid-coated mesoporous silica nanoparticle (LP-MSN) delivery system, we intend to enhance therapeutic efficacy while circumventing DTX resistance mediated by CYP3A4 expression.

METHODS

We rigorously tested TNBC cell lines to confirm the responsiveness to Docetaxel (DTX) and Tamoxifen (TMX). We adeptly engineered LP-MSN nanoparticles and conducted a thorough examination of the optimal drug release strategy, evaluating the LP-MSN system's ability to mitigate the impact of CYP3A4 on DTX. Additionally, we comprehensively analyzed its pharmacological performance.

RESULTS

Our innovative approach utilizing TMX and DTX within LP-MSN showcased remarkable efficacy. Sequential drug release from the lipid layer and mesoporous core curbed CYP3A4-mediated metabolism, substantially enhancing cytotoxic effects on TNBC cells without harming normal cells.

CONCLUSION

This pioneering research introduces a breakthrough strategy for tackling TNBC. By capitalizing on synergistic TMX and DTX effects via LP-MSN, we surmount drug resistance mediated by CYP3A4. This advancement holds immense potential for transforming TNBC treatment, warranting further clinical validation.

Major cardiovascular adverse events in older adults with early-stage triple-negative breast cancer treated with adjuvant taxane + anthracycline versus taxane-based chemotherapy regimens: A SEER-medicare study

BACKGROUND

Triple-negative breast cancer (TNBC) is more aggressive as compared to other subtypes of breast cancer with characteristic metastatic patterns and a poor prognosis. The standard of care for early-stage TNBC is historically anthracycline and taxane-based chemotherapy (ATAX). Despite the effectiveness of this regimen, anthracyclines carry a small but important risk of cardiotoxicity, which is specifically a concern in the older population. This study evaluates major adverse cardiovascular events (MACE) in older women with TNBC treated with ATAX compared to taxane-based chemotherapy (TAX).

METHODS

Using the Surveillance, Epidemiology, and End Results (SEER)-Medicare database, we identified women aged 66 and older with TNBC diagnosed between 2010 and 2015 (N = 2215). We compared patient and clinical characteristics according to adjuvant chemotherapy regimen (chemotherapy versus no chemotherapy and ATAX versus TAX). Logistic regression was performed to estimate the odds ratios (OR) and 95% confidence intervals (CIs), Kaplan-Meier survival curves were generated to estimate three-year overall survival (OS) and cancer specific survival (CSS). Cox proportional hazards models were used to analyze OS and CSS while controlling for patient and tumor characteristics. MACE was defined as acute myocardial infarction, heart failure, potentially fatal arrhythmia, and cerebral vascular incidence. Few patients experienced a cardiac death and therefore this was excluded in the analysis.

RESULTS

Of the 2215 patients in our cohort, most patients (n = 1334; 60.26%) received TAX compared to ATAX (n = 881; 39.78%). Patients who received ATAX were not statistically significantly more likely than those who received TAX to experience acute myocardial infarction, cerebral vascular accident (CVA), or potentially fatal arrhythmia when controlling for traditional risk factors. Among patients who experienced MACE, there was no difference in OS or CSS in patients who received TAX vs ATAX. Patients who received ATAX were less likely to develop heart failure than those who received TAX (OR 0.63, 95% CI [0.45-0.88], p < 0.01). Patients who developed MACE and who were > 76 years old had worse OS compared to those who experienced MACE and were age 66-75 years old (HR 1.67, 95% CI [1.07-2.62], p = 0.02).

CONCLUSION

Among older women with TNBC, receipt of adjuvant chemotherapy with ATAX was not associated with increased risk of major adverse cardiac events. For those who experienced a cardiac event, there was no difference in survival amongst those who received TAX vs ATAX. Other factors including additional chemotherapy toxicities should be investigated as a potential etiology for the inferior OS previously observed with ATAX vs TAX in older women with node negative or 1-3 positive lymph nodes.

Long-chain noncoding RNA LINC01569 upregulates filamin A-interacting protein 1-like to prevent metastasis of triple-negative breast cancer via sponging miR-300

BACKGROUND

Long-chain noncoding RNA (lncRNA), LINC01569, is important for regulating the extracellular matrix, which affects cell migration. However, its involvement in the occurrence and development of triple-negative breast cancer (TNBC) remains unclear.

OBJECTIVE

This study is aimed to investigate the role of LINC01569 on TNBC.

METHODS

Online database was used for clinical data analysis. Cell viability and migration capability were monitored using cell counting kit-8 and transwell assays, respectively. Luciferase reporter assay and RNA pull-down were used to confirm the binding capability between noncoding RNAs and filamin A-interacting protein 1-like (FILIP1L). Western blotting was used to determine the protein content.

RESULTS

Compared with normal breast tissue, LINC01569 was significantly reduced in patients with TNBC subtype, and LINC01569 expression gradually decreased with the progression of tumor stage. Patients with TNBC with high lncRNA LINC01569 levels had a better prognosis than did patients with low LINC01569 levels. LINC01569 overexpression inhibited the migration capability, whereas siRNA-mediated LINC01569 downregulation promoted the migration capability in TNBC cells. Using ENCORI and lncRNA SNP online databases, miR-300 was screened as the potential sponge of LINC01569. The binding of LINC01569 to miR-300 was confirmed using the dual-luciferase reporter and RNA pull-down assays. miR-300 was negatively correlated with LINC01569, and miR-300 mimics eliminated the anti-proliferation and anti-migration effects of LINC01569 on TNBC cells. Additionally, FILIP1L was further verified as the downstream target of miR-300. miR-300 mimics blocked LINC01569 upregulation-mediated elevation of FILIP1L. Importantly, the anti-tumor effects mediated by LINC01569 overexpression were abolished by miR-300 mimics and further restored by FILIP1L upregulation.

CONCLUSIONS

LINC01569 was expressed at a low level in TNBC and could sponge miR-300 to promote FILIP1L expression, reducing the proliferation and metastasis capability of TNBC. Thus, LINC01569 might be a useful biomarker in the diagnosis and prognosis of metastatic TNBC.

Discovery of a potent and selective PARP1 degrader promoting cell cycle arrest via intercepting CDC25C-CDK1 axis for treating triple-negative breast cancer

PARP1 is a multifaceted component of DNA repair and chromatin remodeling, making it an effective therapeutic target for cancer therapy. The recently reported proteolytic targeting chimera (PROTAC) could effectively degrade PARP1 through the ubiquitin-proteasome pathway, expanding the therapeutic application of PARP1 blocking. In this study, a series of nitrogen heterocyclic PROTACs were designed and synthesized through ternary complex simulation analysis based on our previous work. Our efforts have resulted in a potent PARP1 degrader D6 (DC50 = 25.23 nM) with high selectivity due to nitrogen heterocyclic linker generating multiple interactions with the PARP1-CRBN PPI surface, specifically. Moreover, D6 exhibited strong cytotoxicity to triple negative breast cancer cell line MDA-MB-231 (IC50 = 1.04 µM). And the proteomic results showed that the antitumor mechanism of D6 was found that intensifies DNA damage by intercepting the CDC25C-CDK1 axis to halt cell cycle transition in triple-negative breast cancer cells. Furthermore, in vivo study, D6 showed a promising PK property with moderate oral absorption activity. And D6 could effectively inhibit tumor growth (TGI rate = 71.4 % at 40 mg/kg) without other signs of toxicity in MDA-MB-321 tumor-bearing mice. In summary, we have identified an original scaffold and potent PARP1 PROTAC that provided a novel intervention strategy for the treatment of triple-negative breast cancer.

SILAC proteomics based on 3D cell spheroids unveils the role of RAC2 in regulating the crosstalk between triple-negative breast cancer cells and tumor-associated macrophages

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, and is characterized by a high infiltration of tumor-associated macrophages (TAMs). TAMs contribute significantly to tumor progression by intricately interacting with tumor cells. Deeply investigating the interaction between TNBC cells and TAMs is of great importance for finding potential biomarkers and developing novel therapeutic strategies to further improve the clinical outcomes of TNBC patients. In this study, we confirmed the interplay using both 3D and 2D co-culture models. The stable-isotype labeling by amino acids in cell culture (SILAC)-based quantitative proteomics was conducted on 3D cell spheroids containing TNBC cells and macrophages to identify the potential candidate in regulating the crosstalk between TNBC and TAMs. Ras-related C3 botulinum toxin substrate 2 (RAC2) was identified as a potential molecule for further exploration, given its high expression in TNBC and positive correlation with M2 macrophage infiltration. The suppression of RAC2 inhibited TNBC cell proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) in vitro. Meanwhile, knocking down RAC2 in TNBC cells impaired macrophage recruitment and M2 polarization. Mechanistically, RAC2 exerted its roles in TNBC cells and TAMs by regulating the activation of P65 NF-κB and P38 MAPK, while TAMs further elevated RAC2 expression and P65 NF-κB activation by secreting soluble mediators including IL-10. These findings highlight the significance of RAC2 as a crucial molecule in the crosstalk between TNBC and TAMs, suggesting it could be a promising therapeutic target in TNBC.

VEGFA/NRP-1/GAPVD1 axis promotes progression and cancer stemness of triple-negative breast cancer by enhancing tumor cell-macrophage crosstalk

Triple-negative breast cancer (TNBC) has long been considered a major clinical challenge due to its aggressive behavior and poor prognosis. Cancer stem cells (CSCs) are known as the main cells responsible for tumor origination, progression, recurrence and metastasis. Here, we report that M2-type tumor-associated macrophages (TAMs) contribute to cancer stemness in TNBC cells via the secretion of VEGFA. Reciprocally, elevated VEGFA expression by TAM-educated TNBC cells acts as a regulator of macrophage polarization, therefore constitute a feed-back loop between TNBC cells and TAMs. Mechanistically, VEGFA facilitates the CSC phenotype via the NRP-1 receptor and downstream GAPVD1/Wnt/β-catenin signaling pathway in TNBC cells. Our study underscores the crosstalk between TNBC cells and TAMs mediated by VEGFA and further clarifies the role and underlying mechanisms of the VEGFA/NRP-1/GAPVD1 axis in regulating cancer stemness. We also document an immunosuppressive function of VEGFA in the tumor microenvironment (TME). Therefore, the present study indicates crosstalk between TNBC cells and TAMs induced by VEGFA and provides a potential implication for the combination of immunotherapy and VEGFA-targeted agents in TNBC therapy.

Human Serum Albumin-Oxaliplatin (Pt(IV)) prodrug nanoparticles with dual reduction sensitivity as effective nanomedicine for triple-negative breast cancer

Nanomedicines have emerged as a potential strategy to reduce the toxic effect of drugs administered via conventional approaches. Nanomedicines undergo passive and active targeting of the tumor tissues, thereby causing localized drug delivery and reducing drug demand and side effects. Here, we prepared reduction-sensitive oxaliplatin-conjugated human serum albumin nanoparticles with a small size, uniform surfaces, and a satisfactory encapsulation coefficient. The findings of cellular studies demonstrate that utilizing human serum albumin is effective for active tumor targeting. The presence of glutathione-sensitive disulfide linkers in the crosslinking agent and between Pt(IV) and HSA provided dual reduction sensitivity. Cytotoxicity and cell death were enhanced compared to free Oxaliplatin. The outcomes demonstrate that the approach maximized Oxaliplatin's ability to control tumor growth, induced apoptosis, and reduced drug resistance. Therefore, for the first time, our results imply that OXA-SS-HSA NPs were biocompatible, smart, and effective anticancer nanomedicine for triple-negative breast cancer therapy.

Deubiquitinating enzyme OTUD4 regulates metastasis in triple-negative breast cancer by stabilizing Snail1

Metastasis is the primary cause of cancer-related deaths and remains poorly understood. Deubiquitinase OTU domain containing 4 (OTUD4) has been reported to regulate antiviral immune responses and resistance to radio- or chemo-therapies in certain cancers. However, the role of OTUD4 in cancer metastasis remain unknown. Here, we demonstrate that the depletion of OTUD4 in triple-negative breast cancer (TNBC) cells markedly suppress cell clonogenic ability, migration, invasion and cancer stem cell population in vitro as well as metastasis in vivo. Mechanistically, the tumor promoting function of OTUD4 is mainly mediated by deuiquitinating and stabilizing Snail1, one key transcriptional factor in the epithelial-mesenchymal transition. The inhibitory effect of targeting OTUD4 could be largely reversed by the reconstitution of Snail1 in OTUD4-deficient cells. Overall, our study establishes the OTUD4-Snail1 axis as an important regulatory mechanism of breast cancer metastasis and provides a rationale for potential therapeutic interventions in the treatment of TNBC.

PKMYT1 Promotes Epithelial-Mesenchymal Transition Process in Triple-Negative Breast Cancer by Activating Notch Signaling

Background

Triple-negative breast cancer (TNBC) is a subtype of breast cancer (BC) that lacks receptors for targeted therapy. Deeper insight into the molecular mechanisms regulating TNBC metastasis is urgently needed. The epithelial-mesenchymal transition process facilitates the metastasis of neighboring epithelial tumor cells. Protein kinase, membrane-associated tyrosine/threonine 1 (PKMYT1), a member of the Wee family of protein kinases, is upregulated in BC, and its high expression predicts poor prognosis in BC patients. Notch signaling activation is a pathognomonic feature of TNBC. PKMYT1 has been found to induce EMT in non-small cell lung cancer by activating Notch signaling. However, whether PKMYT1 exerts effects on TNBC progression by regulating Notch signaling remains unknown.

Objectives

The objective of this study was to investigate whether PKMYT1 exerts effects on TNBC progression by regulating Notch signaling.

Methods

Fifty cases of surgically resected BC samples (tumor and adjacent non-tumor tissue samples) were collected from patients diagnosed with BC. We measured the expression of PKMYT1 in clinical samples with real-time quantitative polymerase chain reaction (RT-qPCR). For in vitro analysis, RT-qPCR and Western blotting were conducted to evaluate PKMYT1 expression in TNBC cells. Then, the viability, migration, and invasion of TNBC cells were detected by cell counting kit-8 assays, wound healing assays, and Transwell assays. The EMT event was examined by evaluating the levels of EMT-associated proteins. For in vivo analysis, xenograft models in nude mice were established to explore PKMYT1 roles. E-cadherin and Ki67 expression in xenograft models were estimated by immunohistochemistry staining. Hematoxylin and eosin staining was performed to assess tumor metastasis. The underlying mechanisms by which PKMYT1 affected the malignant phenotypes of TNBC cells were explored by Western blotting measuring the pathway-associated proteins.

Results

PKMYT1 was upregulated in BC tissues and cells, and its knockdown prevented cell proliferation, migration, invasion, and EMT event in TNBC. Mechanistically, Notch signaling was inactivated by PKMYT1 depletion, and Notch activation abolished the PKMYT1 silencing-induced inhibition in the malignant phenotypes of TNBC cells. For in vivo analysis, PKMYT1 knockdown inhibited tumorigenesis and metastasis of TNBC.

Conclusion

PKMYT1 promotes EMT, proliferation, migration, and invasion of TNBC cells and facilitates tumor growth and metastasis by activating Notch signaling.

National trends in neoadjuvant chemotherapy utilization in patients with early-stage node-negative triple-negative breast cancer: the impact of the CREATE-X trial

PURPOSE

Neoadjuvant chemotherapy (NAC) for triple-negative breast cancer (TNBC) allows for assessment of tumor pathological response and has survival implications. In 2017, the CREATE-X trial demonstrated survival benefit with adjuvant capecitabine in patients TNBC and residual disease after NAC. We aimed to assess national rates of NAC for cT1-2N0M0 TNBC before and after CREATE-X and examine factors associated with receiving NAC vs adjuvant chemotherapy (AC).

METHODS

A retrospective cohort study of women with cT1-2N0M0 TNBC diagnosed from 2014 to 2019 in the National Cancer Database (NCDB) was performed. Variables were analyzed via ANOVA, Chi-squared, Fisher Exact tests, and a multivariate linear regression model was created.

RESULTS

55,633 women were included: 26.9% received NAC, 52.4% AC, and 20.7% received no chemotherapy (median ages 53, 59, and 71 years, p < 0.01). NAC utilization significantly increased over time: 19.5% in 2014-15 (n = 3,465 of 17,777), 27.1% in 2016-17 (n = 5,140 of 18,985), and 33.6% in 2018-19 (n = 6,337 of 18,871, p < 0.001). On multivariate analysis, increased NAC was associated with younger age (< 50), non-Hispanic white race/ethnicity, lack of comorbidities, cT2 tumors, care at an academic or integrated-network cancer program, and diagnosis post-2017 (p < 0.05 for all). Patients with government-provided insurance were less likely to receive NAC (p < 0.01). Women who traveled > 60 miles for treatment were more likely to receive NAC (p < 0.01).

CONCLUSION

From 2014 to 2019, NAC utilization increased for patients with cT1-2N0M0 TNBC. Racial, socioeconomic, and access disparities were observed in who received NAC vs AC and warrants interventions to ensure equitable care.

Pulmonary Tumor Thrombotic Microangiopathy in a Patient with Rapid Progressive Triple-Negative Breast Cancer

Introduction

Pulmonary tumor thrombotic microangiopathy (PTTM) is a rare complication of metastatic carcinoma, which occurs in patients with pulmonary arterial hypertension, and is mostly fatal. Circulating tumor cell clusters have been recognized as critical factors during breast cancer progression.

Case Presentation

An 80-year-old woman with triple-negative breast cancer was admitted to our hospital with progressive dyspnea and lower back pain. Breast cancer treatment included mastectomy, neoadjuvant and adjuvant chemotherapy as well as adjuvant radiotherapy, receiving her last cycle of radiotherapy 8 days before death. At admission, D-dimers were strongly elevated and platelets were low. NT-pro-BNP was moderately elevated. A CT scan of the chest did not show pulmonary embolism but revealed interlobular septal thickening, centrilobular consolidation, and distension of the pulmonary arteries. Moreover, new skeletal and most likely lymphatic metastasis was described. Treatment with oxygen and oral glucocorticoids was initiated, assuming radiotherapy-induced pneumonitis. Due to low expression of PD-L1 and her markedly bad performance status, tumor-specific therapy was not possible, and the treatment regimen was changed to best supportive care. The patient died 8 days after admission. Autopsy revealed numerous events consistent with tumor emboli in the pulmonary vessels, suggesting PTTM.

Conclusion

PTTM is a rare and mostly fatal complication in malignant breast cancer. As an early detection is difficult, further investigation is needed. Circulating tumor cluster cells may be one way to detect PTTM early and improve patients' survival.

Extracellular vesicles-associated miRNAs in triple-negative breast cancer: from tumor biology to clinical relevance

Breast cancer (BC), a heterogeneous group of diseases, is the most frequent type and the leading cause of cancer-related death among women worldwide. Tumor heterogeneity directly impacts cancer progression and treatment, as evidenced by the patients´ diverse prognosis and treatment responses across the distinct molecular subtypes. Triple-negative breast cancer (TNBC), which accounts for 10-20% of all diagnosed BC cases, is an aggressive BC subtype with a challenging prognosis. Current treatment options include systemic chemotherapy and/or target therapies based on PARP and PD-L1 inhibitors for eligible patients. MicroRNAs (miRNAs) are important regulatory non-coding RNAs (ncRNAs) in TNBC tumorigenesis. These molecules are present both intracellularly and released into biofluids, packaged into extracellular vesicles (EVs). Emerging evidence indicates that EVs-associated miRNAs (EVs-miRNAs), transferred from parental to recipient cells, are key mediators of cell-to-cell communication. Considering their stability and abundance in several biofluids, these molecules may reflect the epigenomic composition of their tumors of origin and contribute to mediate tumorigenesis, similar to their intracellular counterparts. This review provides the current knowledge on EVs-miRNAs in the TNBC subtype, focusing on their role in regulating mRNA targets involved in tumor phenotypes and their clinical relevance as promising biomarkers in liquid biopsies.

Deregulated MicroRNAs involved in P53 Signaling Pathway in Breast Cancer with Focus on Triple-negative Breast Cancer

BACKGROUND

Breast cancer (BC), as a heterogenous disease, is the most common cancer among women worldwide. Triple-negative breast cancer (TNBC) is the most aggressive and malignant subtype with a poor prognosis and a high rate of relapse and metastasis that is closely linked to epithelial-mesenchymal transition (EMT). It is well-documented that miRNAs play oncogenic (oncomiR) or tumor-suppressive (TS-miR) roles in controlling apoptosis (apoptomiR), differentiation, cell proliferation, invasion, migration, etc. Regarding the regulatory roles of miRNAs in the expression levels of various genes, dysfunction or deregulated expression of these molecules can lead to various disorders, including various types of cancers, such as BC. Many miRNAs have been identified with critical contributions in the initiation and development of different types of BCs due to their influence on the p53 signaling network.

OBJECTIVE

The aim of this review was to discuss several important deregulated miRNAs that are involved in the p53 signaling pathway in BC, especially the TNBC subtype. Finally, miRNAs' involvement in tumor properties and their applications as diagnostic, prognostic, and therapeutic agents have been elaborated in detail.

RESULTS

The miRNA expression profile of BC is involved in tumor-grade estrogen receptor (ER) and progesterone receptor (PR) expression, and other pathological properties from luminal A to TNBC/basal-like subtypes via p53 signaling pathways.

CONCLUSION

Developing our knowledge about miRNA expression profile in BC, as well as molecular mechanisms of initiation and progression of BC can help to find new prognostic, diagnostic, and therapeutic biomarkers, which can lead to a suitable treatment for BC patients.

Durable Response to Programmed Death 1-Directed Antibodies in a Hypermutated Triple-Negative Breast Cancer: A Case Report

Introduction

The advent of immune checkpoint inhibitors marks significant progress in the evolution of cancer treatment. Recent clinical trials have demonstrated the success of immune-oncologic (IO) agents like pembrolizumab (Keytruda™) in combination with chemotherapy against triple-negative breast cancer (TNBC) [Ann Oncol. 2017 Jun 1;28(6):1388-1398]. There is less literature investigating pembrolizumab in monotherapy and in cases of rare tumor mutational burden.

Case Presentation

Here, we report the case of a 65-year-old Native American and African American woman with previous incomplete lines of therapy diagnosed with recurrent TNBC and pulmonary metastases. Next-generation sequencing of the metastatic nodules demonstrated a significantly hypermutated tumor with rare polyploidy. The patient had a durable (14 months) response and ongoing remission of the metastatic lesions after administering the programmed cell death 1 inhibitor pembrolizumab. No serious immune checkpoint inhibitor-related toxicities or disease progression was observed during the treatment.

Conclusion

Our report describes recurrent TNBC with a rare amount of hypermutation and the successful use of an IO agent as a treatment.

Fat Biology in Triple-Negative Breast Cancer: Immune Regulation, Fibrosis, and Senescence

Obesity, now officially recognized as a disease requiring intervention, has emerged as a significant health concern due to its strong association with elevated susceptibility to diverse diseases and various types of cancer, including breast cancer. The link between obesity and cancer is intricate, with obesity exerting a significant impact on cancer recurrence and elevated mortality rates. Among the various subtypes of breast cancer, triple-negative breast cancer (TNBC) is the most aggressive, accounting for 15% to 20% of all cases. TNBC is characterized by low expression of estrogen receptors and progesterone receptors as well as the human epidermal growth factor 2 receptor protein. This subtype poses distinct challenges in terms of treatment response and exhibits strong invasiveness. Furthermore, TNBC has garnered attention because of its association with obesity, in which excess body fat and reduced physical activity have been identified as contributing factors to the increased incidence of this aggressive form of breast cancer. In this comprehensive review, the impact of obesity on TNBC was explored. Specifically, we focused on the three key mechanisms by which obesity affects TNBC development and progression: modification of the immune profile, facilitation of fibrosis, and initiation of senescence. By comprehensively examining these mechanisms, we illuminated the complex interplay between TNBC and obesity, facilitating the development of novel approaches for prevention, early detection, and effective management of this challenging disease.

Relevance and mechanism of STAT3/miR-221-3p/Fascin-1 axis in EGFR TKI resistance of triple-negative breast cancer

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.

Spatial and Compositional Biomarkers 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 identification of novel therapeutic targets. Deciphering nuances in the tumor microenvironment (TME) may unveil insightful links between anti-tumor immunity and clinical outcomes, yet such connections remain underexplored. Here we employed a dataset derived from imaging mass cytometry of 58 TNBC patient specimens at single-cell resolution and performed in-depth quantifications with a suite of multi-scale computational algorithms. We detected distinct cell distribution patterns among clinical subgroups, potentially stemming from different infiltration related to tumor vasculature and fibroblast heterogeneity. Spatial analysis also identified ten recurrent cellular neighborhoods (CNs) - a collection of local TME characteristics with unique cell components. Coupling of the prevalence of pan-immune and perivasculature immune hotspot CNs, enrichment of inter-CN interactions was associated with improved survival. Using a deep learning model trained on engineered spatial data, we can with high accuracy (mean AUC 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 treatment development in the context of TNBC.

The role and application of vesicles in triple-negative breast cancer: Opportunities and challenges

Extracellular vesicles (EVs) carry DNA, RNA, protein, and other substances involved in intercellular crosstalk and can be used for the targeted delivery of drugs. Triple-negative breast cancer (TNBC) is rich in recurrent and metastatic disease and lacks therapeutic targets. Studies have proved the role of EVs in the different stages of the genesis and development of TNBC. Cancer cells actively secrete various biomolecules, which play a significant part establishing the tumor microenvironment via EVs. In this article, we describe the roles of EVs in the tumor immune microenvironment, metabolic microenvironment, and vascular remodeling, and summarize the application of EVs for objective delivery of chemotherapeutic drugs, immune antigens, and cancer vaccine adjuvants. EVs-based therapy may represent the next-generation tool for targeted drug delivery for the cure of a variety of diseases lacking effective drug treatment.

Adipocyte-derived exosomes promote the progression of triple-negative breast cancer through circCRIM1-dependent OGA activation

Triple-negative breast cancer (TNBC) has an escalating morbidity and a dismal prognosis. Obesity has been reported to be strongly linked to adverse TNBC outcomes. Exosomes (Exos) transport RNA and proteins between cells and serve as intermediaries for cell-to-cell communication. Accumulated evidence suggests that adipose-secreted circular RNAs (circRNAs) can modulate protein glycosylation in TNBC to facilitate tumor cell outgrowth. Herein, exo-circCRIM1 expression was found to be elevated in TNBC patients with a high body fat percentage. Functional experiments demonstrated that by inhibiting miR-503-5p, exo-circCRIM1 enhanced TNBC evolution and metastasis while activating glycosylation hydrolase OGA. Furthermore, OGA negatively regulates FBP1 by decreasing its protein stability. Moreover, the levels of OGA and FBP1 were positively related to the infiltration level of some immune cells in TNBC. These findings indicate that exo-cirCRIM1 secreted by adipocytes contributes to TNBC progression by inhibiting miR-503-5p and activating the OGA/FBP1 signaling pathway. The findings reveal a novel intercellular signaling pathway mediated by adipose-derived exosomes and suggest that treatment targeting the secreted exosome-circCRIM1 may reverse TNBC progression.

PD-L1 blockade TAM-dependently potentiates mild photothermal therapy against triple-negative breast cancer

The present work was an endeavor to shed light on how mild photothermia possibly synergizes with immune checkpoint inhibition for tumor therapy. We established mild photothermal heating protocols to generate temperatures of 43 °C and 45 °C in both in vitro and in vivo mouse 4T1 triple-negative breast cancer (TNBC) models using polyglycerol-coated carbon nanohorns (CNH-PG) and 808 nm laser irradiation. Next, we found that 1) CNH-PG-mediated mild photothermia (CNH-PG-mPT) significantly increased expression of the immune checkpoint PD-L1 and type-1 macrophage (M1) markers in the TNBC tumors; 2) CNH-PG-mPT had a lower level of anti-tumor efficacy which was markedly potentiated by BMS-1, a PD-L1 blocker. These observations prompted us to explore the synergetic mechanisms of CNH-PG-mPT and BMS-1 in the context of tumor cell-macrophage interactions mediated by PD-L1 since tumor-associated macrophages (TAMs) are a major source of PD-L1 expression in tumors. In vitro, the study then identified two dimensions where BMS-1 potentiated CNH-PG-mPT. First, CNH-PG-mPT induced PD-L1 upregulation in the tumor cells and showed a low level of cytotoxicity which was potentiated by BMS-1. Second, CNH-PG-mPT skewed TAMs towards an M1-like anti-tumor phenotype with upregulated PD-L1, and BMS-1 bolstered the M1-like phenotype. The synergistic effects of BMS-1 and CNH-PG-mPT both on the tumor cells and TAMs were more pronounced when the two cell populations were in co-culture. Further in vivo study confirmed PD-L1 upregulation both in tumor cells and TAMs in the TNBC tumors following treatment of CNH-PG-mPT. Significantly, TAMs depletion largely abolished the anti-TNBC efficacy of CNH-PG-mPT alone and in synergy with BMS-1. Collectively, our findings reveal PD-L1 upregulation to be a key response of TNBC to mild photothermal stress, which plays a pro-survival role in the tumor cells while also acting as a brake on the M1-like activation of the TAMs. Blockade of mPT‑induced PD‑L1 achieves synergistic anti-TNBC efficacy by taking the intrinsic survival edge off the tumor cells on one hand and taking the brakes off the M1-like TAMs on the other. Our findings reveal a novel way (i.e. mild thermia plus PD-L1 blockade) to modulate the TAMs-tumor cell interaction to instigate a mutiny of the TAMs against their host tumor cells.

Targeting cancer stem cell plasticity in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a highly aggressive breast cancer subtype with limited treatment options. Cancer stem cells (CSCs) are thought to play a crucial role in TNBC progression and resistance to therapy. CSCs are a small subpopulation of cells within tumors that possess self-renewal and differentiation capabilities and are responsible for tumor initiation, maintenance, and metastasis. CSCs exhibit plasticity, allowing them to switch between states and adapt to changing microenvironments. Targeting CSC plasticity has emerged as a promising strategy for TNBC treatment. This review summarizes recent advances in understanding the molecular mechanisms underlying CSC plasticity in TNBC and discusses potential therapeutic approaches targeting CSC plasticity.

High-grade HER2-positive mucoepidermoid carcinoma of the breast: a case report and review of the literature

BACKGROUND

Mucoepidermoid carcinoma of the breast is a rare special type of salivary gland-like tumor of the breast, usually displaying triple-negative phenotype. To date, only 64 cases have been reported in the English literature. Herein, we report the first case of mucoepidermoid carcinoma of the breast with human epidermal growth factor receptor 2 gene amplification.

CASE PRESENTATION

A 58-year-old Caucasian woman treated with breast-conserving surgery, radiotherapy, and chemotherapy for an invasive breast carcinoma of no special type, relapsed 20 years later in the ipsilateral left breast. Histological examination of the core needle biopsy of the relapse deferred to the surgical specimen for the definitive diagnosis, because of the broad differential diagnosis. On the resected specimen we observed the presence of a poorly differentiated carcinoma with mucoepidermoid carcinoma of the breast typical features consisting of epidermoid, intermediate and mucinous cells lacking true keratinization, in keeping with the latest World Health Organization diagnostic criteria. The mucoepidermoid carcinoma of the breast was weakly estrogen receptor and androgen receptor positive and progesterone receptor negative, but exceptionally showed human epidermal growth factor receptor 2 gene amplification. Mastermind-like transcriptional coactivator 2 gene translocations were not detected by fluorescent in situ hybridization. The patient received adjuvant chemotherapy with anti-human epidermal growth factor receptor 2 therapy but no endocrine therapy. After 61 months of follow-up, no signs of local or distant recurrence were observed.

CONCLUSIONS

Mucoepidermoid carcinoma of the breast is a very rare entity. Despite being most frequently triple negative, the standard evaluation of receptor status is mandatory, as well as strict application of World Health Organization diagnostic criteria for correct patient management.

Prenatal BRCA1 epimutations contribute significantly to triple-negative breast cancer development

BACKGROUND

Normal cell BRCA1 epimutations have been associated with increased risk of triple-negative breast cancer (TNBC). However, the fraction of TNBCs that may have BRCA1 epimutations as their underlying cause is unknown. Neither are the time of occurrence and the potential inheritance patterns of BRCA1 epimutations established.

METHODS

To address these questions, we analyzed BRCA1 methylation status in breast cancer tissue and matched white blood cells (WBC) from 408 patients with 411 primary breast cancers, including 66 TNBCs, applying a highly sensitive sequencing assay, allowing allele-resolved methylation assessment. Furthermore, to assess the time of origin and the characteristics of normal cell BRCA1 methylation, we analyzed umbilical cord blood of 1260 newborn girls and 200 newborn boys. Finally, we assessed BRCA1 methylation status among 575 mothers and 531 fathers of girls with (n = 102) and without (n = 473) BRCA1 methylation.

RESULTS

We found concordant tumor and mosaic WBC BRCA1 epimutations in 10 out of 66 patients with TNBC and in four out of six patients with estrogen receptor (ER)-low expression (< 10%) tumors (combined: 14 out of 72; 19.4%; 95% CI 11.1-30.5). In contrast, we found concordant WBC and tumor methylation in only three out of 220 patients with 221 ER ≥ 10% tumors and zero out of 114 patients with 116 HER2-positive tumors. Intraindividually, BRCA1 epimutations affected the same allele in normal and tumor cells. Assessing BRCA1 methylation in umbilical WBCs from girls, we found mosaic, predominantly monoallelic BRCA1 epimutations, with qualitative features similar to those in adults, in 113/1260 (9.0%) of individuals, but no correlation to BRCA1 methylation status either in mothers or fathers. A significantly lower fraction of newborn boys carried BRCA1 methylation (9/200; 4.5%) as compared to girls (p = 0.038). Similarly, WBC BRCA1 methylation was found less common among fathers (16/531; 3.0%), as compared to mothers (46/575; 8.0%; p = 0.0003).

CONCLUSIONS

Our findings suggest prenatal BRCA1 epimutations might be the underlying cause of around 20% of TNBC and low-ER expression breast cancers. Such constitutional mosaic BRCA1 methylation likely arise through gender-related mechanisms in utero, independent of Mendelian inheritance.

PROGRAMMED CELL DEATH LIGAND 1 (PD-L1) EXPRESSION IN TRIPLE NEGATIVE BREAST CANCER CASES IN BENIN CITY

Background

Triple-negative breast cancers (TNBC) have been particularly challenging to manage due to their lack of intrinsic cellular receptors, with the resultant relatively higher morbidity and mortality. Recently, the programmed cell death 1/programmed cell death ligand 1 (PD-1/PD- L1) immune checkpoint pathway has become the focus of immunotherapy, especially for TNBCs. This study aimed to determine the pattern of expression of PD-L1 in TNBC cases in Benin City.

Methods

It was a 3-year retrospective study that involved the PD-L1 immunostaining of the TNBC cases that were diagnosed in the Department of Anatomical Pathology, University of Benin Teaching Hospital, Benin City, from January 1, 2017 to December 31, 2019.

Result

Ninety-two cases of TNBC were tested for PD-L1 expression. Thirteen (14.1%) of the TNBC cases were PDL1 positive to varying degrees on tumour and immune cells. Diffuse tumoural PD-L1 staining was seen in 4 (30.8%) of the PD-L1 positive cases. PD-L1 expression was significantly associated with increasing age up to the fifth decade (p =0.030). All the PD-L1 positive TNBC were invasive breast carcinoma of no special type and mostly grade 2 tumours; however, there was no significant association between PD-L1 expression and histological subtype or grade.

Conclusion

PD-L1 expression was shown to occur at a relatively low rate among TNBC cases in this environment and was significantly associated with increasing age. This study has shown that 14.1% (1 in 7) of our TNBC patients could benefit from immune checkpoint inhibitor therapy.

Emerging treatment approaches for triple-negative breast cancer

Approximately, 15% of global breast cancer cases are diagnosed as triple-negative breast cancer (TNBC), identified as the most aggressive subtype due to the simultaneous absence of estrogen receptor, progesterone receptor, and HER2. This characteristic renders TNBC highly aggressive and challenging to treat, as it excludes the use of effective drugs such as hormone therapy and anti-HER2 agents. In this review, we explore standard therapies and recent emerging approaches for TNBC, including PARP inhibitors, immune checkpoint inhibitors, PI3K/AKT pathway inhibitors, and cytotoxin-conjugated antibodies. The mechanism of action of these drugs and their utilization in clinical practice is explained in a pragmatic and prospective manner, contextualized within the current landscape of standard therapies for this pathology. These advancements present a promising frontier for tailored interventions with the potential to significantly improve outcomes for TNBC patients. Interestingly, while TNBC poses a complex challenge, it also serves as a paradigm and an opportunity for translational research and innovative therapies in the field of oncology.

Diselenium-linked dimeric prodrug nanomedicine breaking the intracellular redox balance for triple-negative breast cancer targeted therapy

Triple-negative breast cancer (TNBC) has been regarded as the strongest malignancy in cases of breast cancer with a poor prognosis. The development of effective treatment strategies for TNBC has always been an urgent and unmet need. The intracellular redox balance is essential for maintaining TNBC cell malignancy. Disrupting intracellular redox balance by enlarging reactive oxygen species (ROS) generation and facilitating glutathione (GSH) depletion to amplify intracellular oxidative stress may be an alternative strategy to eliminate TNBC cells. However, inducing ROS generation and GSH depletion concurrently may be challenging. Herein, a diselenium linked-dimeric prodrug nanomedicine FA-SeSe-NPs was developed to break the intracellular redox homeostasis for TNBC targeted therapy. The dimeric prodrug was synthesized by conjugating two cucurbitacin B (CuB) molecules via one diselenium bond, which was subsequently assembled with FA-PEG-DSPE to form the final nanomedicine FA-SeSe-NPs. Using the active targeting potential of folic acid (FA), FA-SeSe-NPs could accumulate in tumor tissue with elevated levels and then be specifically internalized by cancer cells. In the high ROS and GSH conditions of TNBC cells, the diselenium bond can specifically respond to ROS to produce selenium free radicals to increase ROS and react with GSH to generate S-Se bond to deplete GSH. The released CuB further induced ROS production in TNBC cells. The diselenium bond and CuB functioned synergistically to amplify oxidative stress to kill the TNBC cells. Here, we provide a promising strategy to disrupt the intracellular redox balance of cancer cells for effective TNBC therapy.

The expression of O-linked glycosyltransferase GALNT7 in breast cancer is dependent on estrogen-, progesterone-, and HER2-receptor status, with prognostic implications

GALNT7 is a glycosyltransferase enzyme transferring N-acetylgalactosamine to initiate O-linked glycosylation in the Golgi apparatus. Breast cancer is the most common cancer in women globally. Estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2; ERBB2) are important biomarkers in the prognosis and molecular subtyping of breast cancer. Here, we showed that ER-positive, PR-positive or HER2-positive breast tumors have higher expression of GALNT7 compared to ER-negative, PR-negative or HER2-negative breast tumors, respectively. We found that CpG-aggregated methylation of GALNT7 gene is decreased, and in parallel, its transcript levels are increased in breast cancer compared to healthy breast tissue. We observed that the difference in the expression of GALNT7 between negative and positive status of the receptors is the highest for HER2, followed by ER and PR, pointing that HER2 might be relatively more influential than ER and PR on the expression of GALNT7 in breast cancer. We reported that basal-like breast tumors have decreased expression of GALNT7 compared to non-basal-like tumors, and that high GALNT7 expression is associated with favorable relapse-free and distant metastasis-free survival in HER2 status-dependent manner in breast cancer patients. Moreover, we showed that GALNT7 expression in breast cancer is cell type- (epithelial vs stromal cells), tumor grade- and ethnicity-dependent. Combined, we propose that GALNT7 might contribute to different clinical outcomes depending on the receptor status in breast cancer, and that a better understanding of GALNT7 and its function in the context of breast cancer is needed.

lncRNA SEMA3B-AS1 Inhibits miR-513c-5p to Regulate the Progression of Triple-negative Breast Cancer

BACKGROUND/AIM

Triple-negative breast cancer (TNBC) is the most malignant breast cancer subtype with a short survival time and high morality. There is an urgent need for effective indicators able to predict tumor progression and provide reference for adjusting the therapeutic strategy of TNBC. lncRNA semaphorin 3B antisense RNA1-AS1 (SEMA3B-AS1) was previously identified to be correlated with the stemness and autophagy of breast cancer. SEMA3B-AS1's role in TNBC was investigated in the present study, aiming to explore a novel biomarker for the development and prognosis of TNBC.

MATERIALS AND METHODS

SEMA3B-AS1 expression was detected in tissue samples from 113 TNBC patients using PCR. The clinical significance of SEMA3B-AS1 was assessed by the Chi-square test and Cox analysis. The in vitro function of SEMA3B-AS1 was investigated by CCK8 and Transwell assay. Study of molecular mechanism, correlation analysis and dual-luciferase reporter assay were employed to assess the correlation of SEMA3B-AS1 with miR-513c-5p.

RESULTS

A significant down-regulation of SEMA3B-AS1 was observed in TNBC, which was related to patient TNM stage, lymph node metastasis, and Ki67 levels. SEMA3B-AS1 down-regulation indicated patients' adverse prognoses and served as an independent prognostic factor. In vitro, SEMA3B-AS1 suppressed the stemness, proliferation, and metastasis of TNBC cells. Moreover, SEMA3B-AS1 negatively regulated miR-513c-5p, which could reverse the inhibitory effects of SEMA3B-AS1 on TNBC cells.

CONCLUSION

SEM3B-AS1 indicates the severity of TNBC patients and regulates tumor progression via modulating miR-513c-5p.

Discordance in PD-L1 expression using 22C3 and SP142 assays between primary and metastatic triple-negative breast cancer

AIMS

SP142 and 22C3 assays are approved companion diagnostic assays for anti-PD-1/PD-L1 therapy selection in metastatic triple-negative breast cancer (TNBC). The discordance in PD-L1 status between primary and metastatic tumors in the same patient has been poorly characterized. Here, we examined the concordance of PD-L1 status between the two assays and between primary tumors and metastases for each assay.

METHODS

We retrospectively evaluated tumor samples from 160 patients with TNBC, including 45 patients with paired primary and metastatic tumors. PD-L1 status was assessed using SP142 and 22C3 assays, to determine the immune cell (IC) score, tumor cell (TC) score (SP142 and 22C3), and combined proportion score (CPS: 22C3).

RESULTS

The concordance of PD-L1 positivity at diagnostic cutoffs for SP142 (IC ≥ 1) and 22C3 (CPS ≥ 10) was substantial (κ = 0.80) in primary tumors and moderate (κ = 0.60) in metastatic tumors. In comparison, between primary and metastatic tumors, the concordance with 22C3 was moderate (κ = 0.50), whereas that with SP142 was poor (κ = -0.03). Among patients who were PD-L1 negative for both assays in primary tumors, 7/30 (23.3%) were PD-L1 positive for both or either 22C3 or SP142 in the metastatic tumors.

CONCLUSIONS

The inter-assay concordance of PD-L1 positivity at diagnostic cutoffs was substantial in primary tumors and moderate in metastatic tumors. Discordance between PD-L1 status in primary and metastatic tumors was frequently observed, especially with SP142. Some patients with a PD-L1-negative status in primary tumors may still be candidates for immunotherapy, depending on the PD-L1 status in their metastatic tumors.