Tumor-infiltrating lymphocytes (TILs) are a valuable indicator of the immune microenvironment that plays the central role in new anticancer drugs. TILs has a strong prognostic role in triple negative breast cancer (TNBC). Little is known about his interaction with Androgen receptor (AR) and Forkhead box A1 (FOXA1). We analyzed the relationships between TIL levels, AR and FOXA1 expression and their clinical significance in TNBC patients. Further, we investigated their interaction with other biomarkers like programmed cell death ligand-1 (PD-L1), Breast Cancer Type 1 susceptibility protein (BRCA1), Poly [ADP-Ribose] Polymerase 1 (PARP1) and Na+/H+ Exchanger Regulatory Factor 1 (NHERF1). The expression of the proteins was evaluated by immunohistochemistry in 124 TNBC samples. TILs were performed adhering to International TILs Working Group 2014 criteria. Cox proportional hazards models were also used to identify risk factors associated with poor prognosis. Multivariate analysis identified TILs as independent prognostic factor of disease free survival (DFS) (p=0.045). A Kaplan-Meyer analysis revealed that the patients with high TILs had a better DFS compared to patients with low TILs (p=0.037), and the phenotypes TILs-/AR+ and TILs-/FOXA1- had a worse DFS (p=0.032, p=0.001 respectively). AR was associated with FOXA1 expression (p=0.007), and the tumors FOXA1+ presented low levels of TILs (p=0.028). A poor DFS was observed for AR+/FOXA1+ tumors compared to other TNBCs (p=0.0117). Low TILs score was associated with poor patients’ survival, and TILs level in combination with AR or FOXA1 expression affected patient’s clinical outcome. In addition, AR+/FOXA1+ phenotype identified a specific subgroup of TNBC patients with poor prognosis. These data may suggest new ways of therapeutic intervention to support current treatments.

Triple-negative breast cancer (TNBC) is a subtype of breast cancer that disproportionally accounts for the majority of breast cancer-related deaths due to the lack of specific targets for effective treatments. While there is immense focus on the development of novel therapies for TNBC treatment, a persistent and critical issue is the rate of heart failure and cardiomyopathy which is a leading cause of mortality and morbidity amongst cancer survivors. In this review, we highlight mechanisms of cardiotoxicity post-chemotherapeutic exposure, assess how this is assessed clinically and highlight the transforming growth factor-beta family (TGF-β) pathway and discuss its role as a mediator of cardiomyopathy. We highlight recent findings demonstrating TGF-β inhibition as a potent method to prevent cardiac re-modeling, fibrosis and cardiomyopathy. We describe how dysregulation of the TGF-β pathway is associated with negative patient outcomes across 32 types of cancer including TNBC. We then highlight how TGF-β modulation may be a potent method to target mesenchymal (CD44+/CD24-) and epithelial (ALDHhigh) cancer stem cell (CSC) populations in TNBC models. CSCs are associated with tumorigenesis, metastasis, relapse, resistance, and diminished patient prognosis; however, due to plasticity and differential regulation these populations remain difficult to target and persist as a major barrier barring successful therapy. TGF-β inhibition represents an intersection of two fields: cardiology and oncology. Through inhibiting cardiomyopathy, cardiac damage and heart failure may be prevented and through CSC targeting, patient prognosis may be improved. Together, both approaches, if successfully implemented would target the two greatest causes of cancer-related morbidity in patients and potentially lead to a breakthrough therapy.

(1) Background: Triple negative breast cancer (TNBC) is a distinct subgroup of breast cancer presenting high level of recurrence and neo-adjuvant chemotherapy is beneficial in its therapy management. Anti-PD-L1 immunotherapy improves effect of neo-adjuvant therapy in TNBC. (2) Methods: Immune-modulation and ferroptosis related R-packages were developed for integrative transcriptome to analyze transcriptome datasets: TNBC cells stimulated with ferroptosis inducers (GSE173905, GSE154425), breast tumors with clinical data (TCGA and METABRIC cohorts). Protein level validation was investigated through protein atlas proteome experiments. (3) Results: Erastin/RSL3 ferroptosis inducers up-regulate CD274 in TNBC cells (MDA-MB-231 and HCC38). In breast cancer, CD274 expression is associated to overall survival. Breast tumors presenting high expression of CD274 up-regulated some ferroptosis drivers associated to prognosis: IDO1, IFNG and TNFAIP3. CD274-ferroptosis-driver score computed on breast tumor transcriptome stratified patients on their prognosis: low score was observed in basal subgroup with higher level of recurrent risk scores: oncotypeDx, ggi and gene70 scores. In METABRIC cohort, CD274, IDO1, IFNG and TNFAIP3 were found overexpressed in TNBC subgroup. CD274-ferroptosis-driver score was found associated to overall survival independently of TNM classification and age diagnosis. Tumor expression of CD274, TNFAIP3, IFNG and IDO1 in biopsy of breast ductal carcinoma was confirmed at protein level (4) Conclusion: Ferroptosis inducers up-regulate PD-L1 in TNBC cells, known as effective target of immunotherapy in high risk early TNBC which received neo-adjuvant therapy. Basal and TNBC tumors highly expressed CD274 and ferroptosis drivers: IFNG, TNFAIP3 and IDO1. CD274-ferroptosis driver score is associated to prognosis and to the risk of recurrence in breast cancer. A potential synergy of ferroptosis inducers with anti-PD-L1 immunotherapy is suggested in recurrent TNBC.

The main known function of Nudix hydrolase 2 (Nudt2) is to hydrolyze the secondary messenger diadenosine 5', 5’’’-p1, p4-tetraphosphate (Ap4A). In this study we examined the role of Nudt2 in breast carcinoma through its expression in the human invasion ductal carcinoma tissues, and its functions in human triple negative breast cancer (TNBC) cell lines. A significantly high expression of Nudt2 in the human invasion ductal carcinoma tissues was observed in our study. Knockdown of Nudt2 in TNBC cell lines showed a significant reduction in cellular proliferation via the Ki67 marker, accompanied by G0/G1 phase cell cycle arrest. A significant reduction in the migration and invasion of Nudt2 knockdown TNBC cell lines was also observed. The effect of Nudt2 knockdown in the TNBC cell lines on tumorigenicity and anchorage-independent growth was assessed, where significant reductions in the Nudt2 knockdown TNBC cell lines were found. It can therefore be concluded that Nudt2 plays a significant role in promoting TNBC growth.

Venoms are a rich source of bioactive compounds, and among them is leberagin-C (Leb-C), a disintegrin-like protein derived from the venom Macrovipera lebetina transmediterrannea snakes. Leb-C has shown promising inhibitory effects on platelet aggregation. Previous studies have demonstrated that this SECD protein specifically targets α5β1, αvβ3 and αvβ6 integrins through a mimic mechanism of RGD disintegrins. In our current study, we focused on exploring the potential effects of Leb-C on metastatic breast cancer. Our findings revealed that Leb-C disrupted the adhesion, migration, and invasion capabilities of MDA-MB-231 breast cancer cells and its highly metastatic D3H2LN sub-population. Additionally, we observed significant suppression of adhesion, migration, and invasion of Human Umbilical Vein Endothelial Cells (HUVECs). Furthermore, Leb-C demonstrated a strong inhibitory effect on fibroblast growth factor 2-induced proliferation of HUVEC. We conducted in vivo experiments using nude mice and found that treatment with 2 µM of Leb-C resulted in a remarkable 73% reduction in D3H2LN xenograft tumor size. Additionally, quantification of intratumor microvessels revealed a 50 % reduction in tumor angiogenesis in xenograft after 21 days of twice-weekly treatment with 2 µM of Leb-C. Collectively, these findings suggest the potential utility of this dinsintegrin-like protein for inhibiting aggressive and resistant metastatic breast cancer.

BUB1 is overexpressed in most human solid cancers including breast cancer. Higher BUB1 levels are associated with poor prognosis especially in patients with triple-negative breast cancer (TNBC). Women with TNBC often develop resistance to chemotherapy and radiotherapy, which are still the mainstay of treatment for TNBC. Our previous studies demonstrated that BUB1 kinase inhibitor (BAY1816032) reduced tumor cell proliferation and significantly enhanced radiotherapy efficacy in TNBC. In this study, we evaluated the effectiveness of BAY1816032 with a PARP inhibitor (olaparib), platinum agent (cisplatin), and microtubule poison (paclitaxel) alone or in combination with radiotherapy using cytotoxicity and clonogenic survival assays. BUB1 inhibitor sensitized BRCA1/2 wild-type SUM159 and MDA-MB-231 cells to olaparib, cisplatin and paclitaxel synergistically (combination index; CI

The triple-negative breast cancer (TNBC) subtype is one of the most aggressive forms of breast cancer that has poor clinical outcome and still remains as an unmet clinical challenge. Accumulating evidence suggests that intratumoral heterogeneity or the presence of phenotypically heterogeneous cell populations within a tumor plays a crucial role in chemoresistance, tumor progression and metastasis. Increased understanding of the molecular regulators of intratumoral heterogeneity will enable the development of effective therapeutic strategies in TNBC. We have identified a molecular mediator involved in intratumoral heterogeneity in breast cancer using an unbiased approach. We isolated two heterogeneous tumor cell populations from the 4T1 TNBC tumor model and phenotypic characterization revealed that the cells are distinct in terms of their morphology, proliferation and self-renewal ability in vitro; as well as primary tumor formation and metastatic potential in vivo. Further, RNA sequencing on both cell populations was performed to identify the molecular mediators underlying this heterogeneity. Bioinformatic analysis performed on the differentially expressed genes along with the Kaplan-Meier survival analysis in TNBC patients identified Metastasis associated colon cancer 1 (Macc1) as the top candidate gene mediating the aggressive phenotype. The role of Macc1 in regulating the proliferative phenotype was validated using siRNA mediated gene knockdown. The role of Macc1 in the aggressive cancer cell phenotypes and disease progression is being studied further using a small molecule transcriptional inhibitor of Macc1 in cell line and animal models, thus increasing our understanding of the molecular underpinnings of intratumoral heterogeneity in breast cancer that is critical to the improvement in the treatment of women currently living with the highly aggressive TNBC subtype.

To assess AR’s role in TNBC treatment, various existing and completed clinical trials targeting AR or co-targeting AR with other pertinent signaling molecules were analyzed. Cyclin-dependent kinase 4/6 (CDK4/6), cytochrome P450 17α-hydroxylase/17,20-lyase (CYP17 lyase), and the phosphatidylinositol 3kinase (PI3K)/protein kinase B (AKT) signaling pathway were some of the most prevalent biomarkers used in combination therapy with AR inhibitors in these trials. Studying how AR functions in tandem with these molecules can have increasing breakthroughs in the treatment options for TNBC. Previous studies have been largely unsuccessful in utilizing AR as the sole drug target for systemic targeted treatment in TNBC. However, there is a lack of other commonly used drug target biomarkers in the treatment of this disease, as well. Thus, analyzing the clinical benefit rate (CBR) within clinical trials that are using combination therapy can prove to be imperative to the progression of improving treatment options and prognoses.

The secretory pathway Ca2+-ATPase SPCA2 is a tumor suppressor in triple receptor negative breast cancer (TNBC), a highly aggressive molecular subtype that lacks tailored treatment options. Low expression of SPCA2 in TNBC confers poor survival prognosis in patients. Previous work has established that re-introducing SPCA2 to TNBC cells restores basal Ca2+ signaling, represses mesenchymal gene expression, mitigates tumor migration in vitro and metastasis in vivo. In this study, we examined the effect of histone deacetylase inhibitors (HDACi) in TNBC cell lines. We show that the pan-HDACi vorinostat and the class I HDACi romidepsin induce dose-dependent upregulation of SPCA2 transcript with concurrent downregulation of mesenchymal markers and tumor cell migration characteristic of epithelial phenotype. Silencing SPCA2 abolished the ability of HDACi to reverse epithelial to mesenchymal transition (EMT). Independent of ATPase activity, SPCA2 elevated resting Ca2+ levels to activate downstream components of non-canonical Wnt/Ca2+ signaling. HDACi treatment led to SPCA2-dependent phosphorylation of CAMKII and -catenin, turning Wnt signaling off. We conclude that SPCA2 mediates the efficacy of HDACi in reversing EMT in TNBC by a novel mode of non-canonical Wnt/Ca2+ signaling. Our findings provide incentive for screening epigenetic modulators that exploit Ca2+ signaling pathways to reverse EMT in breast tumors.

Obesity is one of the most prevalent chronic diseases and has become a global epidemic. Obesity leads to a greater risk of breast cancer (BC), metastases, recurrence, and decreased survival. For sustained weight loss, bariatric surgery is effective as a long-term solution. Bariatric surgery is associated with improved outcomes of several cancers including BC, although the mechanisms mediating this protection are unknown. We hypothesized that elevated bile acid pools detected after bariatric surgery may be factors that contribute to improved BC outcomes. Indeed, patients with greater expression of the bile acid receptor FXR displayed improved survival in specific BC subtypes. Patients with tumors that are estrogen receptor negative (ER-) displayed significantly elevated survival with higher FXR (NR1H4) expression compared to lower expression. FXR is a nuclear hormone receptor activated by bile acids. Therefore, we posited that activating FXR using an established FDA-approved agonist would display anticancer effects. Indeed, FXR agonism by the bile acid mimetic known commercially as OCALIVA (“OCA”), or Obeticholic acid (INT-747), significantly reduced BC progression and overall tumor burden in a pre-clinical model. In human and murine BC analyses in vitro, agonism of FXR significantly and dose-dependently inhibited proliferation, migration, and viability. In contrast, synthetic agonism of another common bile acid receptor, the G protein-coupled bile acid receptor (GPBAR1, TGR5) which is mainly activated by secondary bile acids, failed to significantly alter cancer cell dynamics. In conclusion, agonism of FXR by primary bile acid memetic OCA yields potent anti-tumor effects potentially through inhibition of proliferation and migration and reduced cell viability. Findings suggest that FXR is a tumor suppressor gene with high potential for personalized therapeutic strategies for individuals with BC.

The amino acid transporters SLC38A5 and SLC7A11 are upregulated in triple-negative breast cancer (TNBC). SLC38A5 transports glutamine, methionine, glycine and serine, and therefore activates mTOR signaling and induces epigenetic modifications. SLC7A11 transports cystine and increases cellular levels of glutathione, which protects against oxidative stress and lipid peroxidation via glutathione peroxidase, a seleno (Se)-enzyme. The primary source of Se is dietary Se-methionine (Se-Met). Since SLC38A5 transports methionine, we examined its role in Se-Met uptake in TNBC cells. We found that SLC38A5 interacts with methionine and Se-Met with comparable affinity. We also examined the influence of Se-Met on Nrf2 in TNBC cells. Se-Met activated Nrf2 and induced expression of Nrf2-target genes, including SLC7A11. Our previous work discovered niclosamide, an antiparasitic drug, as a potent inhibitor of SLC38A5. Here we found SLC7A11 to be inhibited by niclosamide with an IC50 value in the range of 0.1-0.2 M. In addition to the direct inhibition of SLC38A5 and SLC7A11, pretreatment of TNBC cells with niclosamide reduced the expression of both transporters. Niclosamide decreased glutathione levels, inhibited proliferation, suppressed GPX4 expression, increased lipid peroxidation, and induced ferroptosis in TNBC cells. It also significantly reduced the growth of the TNBC cell line MB231 in mouse xenografts.

Triple negative breast cancer (TNBC) is the most aggressive breast cancer accounting for around 15% of identified breast cancer cases. TNBC, by lacking estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2), is unresponsive to current targeted therapies. Existing treatment relies on chemotherapeutic treatment but, despite an initial response to chemotherapy, the inception of resistance and relapse is unfortunately common. Dasatinib is an approved second-generation inhibitor of multiple tyrosine kinases and literature data strongly support its use in the management of TNBC. However, dasatinib binds to plasma proteins and undergoes extensive metabolism through oxidation and conjugation. To protect dasatinib from fast pharmacokinetic degradation and to prolong its activity, it was encapsulated on poly(styrene-co-maleic acid) (SMA) micelles. The obtained SMA-dasatinib nanoparticles (NPs) were evaluated for their physicochemical properties, in vitro antiproliferative activity in different TNBC cell lines, and in vivo anticancer activity in a syngeneic model of breast cancer. Obtained results showed that SMA-dasatinib is more potent against 4T1 TNBC tumor growth in vivo compared to free drug. This enhanced effect was ascribed to the encapsulation of the drug protecting it from a rapid metabolism. Our finding highlights the often-overlooked value of nanoformulations in protecting its cargo from degradation. Overall, results may provide an alternative therapeutic strategy for TNBC management.

(1) Background: Retroareolar breast tumors are common, but they rarely progress to malignancy. This report presents a case of a 41-years-old woman with a superficial breast tumor, emphasizing the significance of considering a wide range of options when evaluating breast lumps. (2) Methods: The patient presented with a steadily growing, ulcerating superficial tumor in her left breast. To determine the nature of the tumor, a diagnostic assessment was conducted, which included a positron emission tomography (PET) scan and histological analysis. (3) Results: The diagnostic assessment confirmed the presence of a malignant Grade II superficial infiltrating ductal carcinoma. Following the diagnosis, the patient underwent a modified radical mastectomy under general anesthesia. Subsequently, she received four cycles of adjuvant chemotherapy, followed by taxol administrations. (5) Conclusions: This case report underscores the importance of conducting a thorough examination and maintaining a high index of suspicion for breast tumors. By documenting this case, the report contributes to the existing knowledge on various manifestations of breast cancer and highlights the necessity of early identification and aggressive treatment. This knowledge can be applied to identify and manage similar cases in the future, leading to improved patient outcomes.

Recent works identified ClpXP, mitochondrial caseinolytic protease, as the only target of imipridones - new class of antitumor agents. Our study of the mechanism of imipridone derivative TR-57 action in SUM159 human breast cancer cells demonstrated mitochondrial fragmentation, degradation of mitochondrial mtDNA and mitochondrial dysfunction, due to inhibition of Complex I and Complex II activity. Complete inhibition of oxidative phosphorylation accom-panied with 90, 94, 88 and 87% decrease in the content of Complex I, II, III and IV proteins, respectively. The content of the FOF1-ATPase subunits decreased sharply by approximately 35% after 24 hours and remained unchanged up to 72 hours of incubation with TR-57. At the same time, a disappearance of the ATPIF1, natural inhibitor of mitochondrial FOF1-ATPase observed after 24 h exposure to TR-57. ATPase inhibitor oligomycin had no effect on the mitochondrial membrane potential in intact SUM159, whereas it caused a 65% decrease in TR-57-treated cells. SUM159 cells incubated with TR57 up to 72 hours retained the level of proteins facilitating the ATP transfer across the mitochondrial membranes: VDAC1 expression was not affected, while expression of ANT-1/2 and APC2 increased by 20% and 40%, respectively. Thus, our results suggest that alt-hough TR-57 treatment lead to complete inhibition of respiratory chain activity of SUM159 cells, hydrolysis of cytoplasmic ATP by reversal activity of FOF1-ATPase supports mitochondrial polarization.

We previously described a model of deep intrinsic resistance of breast cancer wherein we used a function-based approach to selection of cancer cells that can survive a variety of challenges in prolonged but reversible quiescence. Our experimental results suggested that resistant cancer cells possess a variety of mechanisms, including modifications of the epigenome and transcriptome, for generating a high degree of cellular heterogeneity. In the present study, we evaluated JIB-04, a small-molecule epigenetic inhibitor initially discovered to inhibit cancer growth, to determine its ability to affect deep intrinsic resistance in our breast cancer model. We found that long pretreatment with JIB-04 sensitized resistant triple-negative inflammatory breast cancer cells and their parental cell line SUM149 to the chemotherapeutic drugs doxorubicin and paclitaxel. Resistant cancer cells derived from another inflammatory breast cancer cell line, FC-IBC02, were considerably more sensitive to JIB-04 than was the parental cell line. Investigating a mechanism of sensitization, we found that JIB-04 exposure increased the expression of PD-L1 in resistant cells, suggesting that JIB-04 may also sensitize resistant breast cancer cells to anti-PD-L1 immune therapy. Finally, these results support the usefulness of our experimental strategy for evaluating anticancer agents such as JIB-04 that may halt cancer evolution and prevent development of cancer resistance to currently used therapies.