Triple-negative breast cancer: the importance of molecular and histologic subtyping, and recognition of low-grade variants

Liposomal oncolytic adenovirus as a neoadjuvant therapy for triple-negative breast cancer

Breast cancer remains one of the leading causes of cancer-related death, with triple-negative breast cancer (TNBC) accounting for 15-20% of cases. TNBC, characterized by the absence of ER, PR, and HER2 protein, is an aggressive form of breast cancer that is unresponsive to hormonal therapies and HER2-targeted treatments, with fewer treatment options and poorer prognosis. Oncolytic adenoviruses (Ad) are a potential treatment option for TNBC but require coxsackievirus and adenovirus receptors (CAR) to effectively enter and transduce cancer cells. This study investigates a novel neoadjuvant therapy to improve the efficacy of an oncolytic Ad with human telomerase reverse transcriptase (Ad-hTERT) in CAR-low TNBC tumors using folate surface-modified liposomes to enhance delivery. This therapy helps deescalate treatment by reducing or eliminating the need for checkpoint inhibitors or toxic chemotherapy combinations. In vitro studies using CAR-low TNBC murine 4T1-eGFP cells, CAR-high TNBC human MDA-MB-231-GFP cells and several other TNBC human cancer cell lines with varying CAR expression demonstrated significantly higher cytotoxicity with encapsulated Ad-hTERT compared to Ad-hTERT. Similar results were observed in patient-derived primary TNBC cells. In vivo studies in immunocompetent mice with CAR-low 4T1-eGFP tumors revealed that encapsulated Ad-hTERT, administered as neoadjuvant therapy, resulted in stable or reduced tumor sizes, improved survival rates, higher apoptosis of cancer cells, lower cancer cell proliferation, and increased T-cell infiltration in resected tumors. Furthermore, encapsulated Ad-hTERT prevented lung metastasis and tumor recurrence at the primary site, resulting in higher survival rates in mice. Thus, liposomal encapsulation of Ad may be a viable strategy for treating TNBC.

A comprehensive review on targeted therapies for triple negative breast cancer: an evidence-based treatment guideline

Triple-negative breast cancer (TNBC) is an aggressive malignancy characterized by limited therapeutic options and poor prognosis. Despite advancements in precision oncology, conventional chemotherapy remains the cornerstone of TNBC treatment, often accompanied by debilitating side effects and suboptimal outcomes. This review presents a comprehensive analysis of clinical trials on targeted therapies, aiming to establish a novel, evidence-based treatment strategy exclusively leveraging molecularly targeted agents. By integrating patient-specific genetic profiles with therapeutic responses observed across various clinical trial phases, this approach seeks to optimize efficacy while minimizing toxicity. The proposed targeted therapy combinations hold significant potential to revolutionize TNBC treatment, offering a paradigm shift toward precision medicine and improved patient outcomes.

Exploration of Traditional Chinese Medicine Comprehensive Treatment of Triple Negative Breast Cancer Based on Molecular Pathological Mechanism

Triple-negative breast cancer (TNBC) is recognized as the most aggressive subtype of breast cancer and is associated with poor prognosis. Clinically, TNBC is associated with significant invasiveness, high propensity for metastasis, frequent recurrence, and unfavorable outcomes. The absence of estrogen receptors, progesterone receptors, and human epidermal growth factor receptor 2 (HER2) in TNBC renders it unresponsive to endocrine therapies and treatments that target HER2. Consequently, the current therapeutic options are primarily confined to surgical intervention, adjuvant chemotherapy, and radiotherapy. Given the considerable heterogeneity of TNBC, targeted therapies have emerged as promising avenues for treatment. Furthermore, immunotherapy has demonstrated the potential to enhance overall survival and therapeutic response in patients with TNBC. Additionally, research indicates that traditional Chinese medicine (TCM) may yield beneficial effects in the management of this cancer subtype. This review aims to consolidate recent advancements in treatment strategies for TNBC, particularly those based on molecular subtypes.

Serous-like breast carcinomas: immunophenotypic, genetic, and clinicopathologic characterization of a morphologically distinct group of tumours

AIMS

Unusual morphologic patterns of breast carcinomas can raise diagnostic consideration for metastasis or special breast cancer subtypes with management implications. We describe rare invasive breast cancers that mimic serous carcinoma of the gynaecologic tract (serous-like breast carcinomas, SLBC) and characterize their clinicopathologic, immunophenotypic, and genetic features.

METHODS AND RESULTS

All patients were female (n = 15, median age 49 years) without a history of gynaecologic malignancy. SLBC were characterized histologically by angulated, branched, sometimes anastomosing glands with micropapillary and/or pseudopapillary luminal projections in desmoplastic stroma. Most SLBC were triple-negative (TN, n = 10) or HER2-positive (n = 2) and grade 2 or 3, while some were oestrogen receptor (ER) low-positive/HER2-negative and low-grade (n = 3). CK5/6 was positive irrespective of grade or receptor status (10/10). All SLBC expressed GATA3 (14/15), TRPS1 (7/7), and/or mammaglobin (4/13). SOX10 was positive in most TN (9/10) and all ER low-positive (3/3) cases, but negative in HER2-positive tumours. WT1 was universally negative, and PAX8 was focal in one mammaglobin-positive tumour. All ER-negative SLBC were p53-aberrant and 9/11 were p16-aberrant, whereas ER-positive tumours were wildtype for both markers (3/3). TP53 was the only frequently mutated gene, altered in all ER-negative (10/10) but no ER-positive (0/4) tumours. Clinical behaviour was variable. Only 1/6 patients achieved pathologic complete response to neoadjuvant chemotherapy.

CONCLUSION

SLBC is a rare morphologic pattern of invasive breast carcinoma that mimics metastatic serous gynaecologic carcinoma, a potential diagnostic pitfall. SLBC are heterogeneous with respect to grade, receptor profile, and oncogenic driver alterations, without specific genetic underpinnings identified. Additional studies are warranted to further evaluate the clinical behaviour of these tumours.

Molecular subtyping and target identification in triple negative breast cancer through immunohistochemistry biomarkers

BACKGROUND

The Triple-Negative Breast Cancer (TNBC) molecular subtyping and target identification based on Immunohistochemistry (IHC) is of considerable worth for routine use. Yet, literature on this topic is limited worldwide and needs to be enriched with data from different populations.

METHODS

We assessed the IHC expression of subtyping biomarkers (Cytokeratins 5, 14 and 17, Epidermal Growth Factor Receptor, Claudins 3 and 7, E-cadherin, Vimentin and Androgen receptor) and predictive biomarkers (Tumor-infiltrating lymphocytes (TILs) density, Breast Cancer Antigen 1 (BRCA1) and P53) in a cohort of TNBC patients. Clinicopathologic parameters and overall survival (OS) were investigated as well.

RESULTS

The patients were aged 50.11 ± 12.13y (more than 40y in 76.56% of patients), and 23.44% had a BC family history. They were in a non-advanced stage: 51.6% T2 stage, 56.2% negative lymph node involvement, 76.6% without metastasis and 64.1% grade II Scarff-Bloom-Richardson classification (SBR). The IHC subtypes were: 53.1% Basal-like1 (BL1), 6.3% Basal-like2 (BL2), 17.2% Mesenchymal (MES), 9.4% Luminal Androgen Receptor (LAR), 4.7% Mixed subtype and 9.4% "Unclassified" type. The LAR subtype involved the youngest patients (40.17 ± 8.68y, p = 0.02). The "Unclassified" subtype expressed the p53 mutated-type pattern more frequently (100%, p = 0.07). The BRCA1 mutated pattern and TILs infiltration were present in (23.44% and 37.5% of patients, respectively). The OS of the subtypes differed significantly (p = 0.007, log-rank test). The subtypes median OS were, respectively, 15.47 mo. (Unclassified), 18.94 mo. (BL2), 27.23 mo. (MES), 27.28 mo. (Mixed), 30.88 mo. (BL1), and 45.07 mo. (LAR). There was no difference in the OS following age, BRCA1 expression, p53 pattern and TILs density. Though, the OS following the TNM stage was different (p = 0.001). A multivariable Cox proportional hazards regression analysis showed that TNM staging and TNBC subtypes, independently influence the OS (p < 0.001 and p = 0.017, respectively). Hence, IHC is useful in TNBC subtyping for prognostic purposes and in the identification of therapeutic biomarkers. Further investigation is required to confirm our results and to implement IHC as a routine tool to improve patient's care.

Deciphering the anti-neoplastic potential of Allium ascalonicum in averting the proliferation and epithelial-mesenchymal transition of triple-negative breast cancer through virtual docking and In Vitro approaches

BACKGROUND

Universally, Allium ascalonicum (Shallots) is a well-known flavouring agent in many cuisines. Though, it's been proved for its health benefits due to the presence of alkaloids, flavonoids, terpenoids, phenols and coumarins, its role as an anti-neoplastic agent still requires comprehensive investigation. In our study, we have investigated the presence of potential anti-neoplastic phytocompounds, anti-inflammatory, cytotoxicity and anti-metastatic activity of Shallots against Triple-Negative Breast Cancer cell line, MDA-MB-231.

METHODS

Phytocompounds of aqueous Allium ascalonicum extract (AAE) derived from GC-MS and LC-MS analysis were docked with an inflammatory marker, Interleukin-18 (IL-18); anti-apoptotic proteins, B-cell Lymphoma-2 (BCL-2) and Myeloid Cell Leukemia-1 (MCL-1); and metastatic marker, Vimentin using PyRx (Version 0.9.9). Subsequently, the anti-inflammatory property of AAE was determined using Bovine Serum Albumin (BSA) Denaturation Assay and the chemotherapeutic potential of AAE was determined using 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay on MDA-MB-231 and HEK293T cell lines. Additionally, to determine the synergistic effect of Doxorubicin Hydrochloride (Standard) and AAE, MTT assay was performed on MDA-MB-231 cell lines treated with the combination therapy. Furthermore, the anti-metastatic property of AAE was determined using cell migration and clonogenic assays. Finally, Dual Acridine Orange/Ethidium Bromide fluorescence staining method was used to determine if AAE has the ability to induce apoptosis and necrosis in MDA-MB-231 cells.

RESULTS

Molecular docking results using the compounds obtained from LC-MS and GC-MS with the target proteins revealed promising anti-neoplastic bioactive compounds. BSA Denaturation assay proved that AAE has anti-inflammatory property, with the highest, 85.78% observed at 2 mg/ml of AAE. Moreover, MTT assay proved that AAE exhibited cytotoxic effect on MDA-MB-231 in a dose-dependent manner, with an IC50 observed at 1.23 mg/ml (**p ≤ 0.005) and non-toxic to HEK293T cells. Combination therapy of the standard with AAE reduced the IC50 of the standard by 65.5%. Consecutively, the anti-metastatic property of AAE was proved using cell migration and clonogenic assays, suggesting suppression of epithelial-mesenchymal transition. Finally, Dual Acridine Orange/Ethidium Bromide fluorescence staining method displayed that, AAE has the ability to induce apoptosis and necrosis in TNBC cells.

CONCLUSION

The outcomes from in vitro assays corroborated with the molecular docking results and hence, on authenticating the potentiality of AAE's anti-neoplastic effect via. in vivo models, pre-clinical and clinical trials, Allium ascalonicum can be articulated to a prospective anti-neoplastic drug for treating TNBC.

Prodelphinidin B-2,3,3"-O-gallate via chemical oxidation of epigallocatechin-3-gallate shows high efficacy inhibiting triple-negative breast cancer cells

BACKGROUND

Triple-negative breast cancer is a clinically aggressive malignancy with poorer outcomes versus other subtypes of breast cancer. Numerous reports have discussed the use of epigallocatechin-3-gallate (EGCG) against various types of cancer. However, the effectiveness of EGCG is limited by its high oxidation and instability. The Notch pathway is critical in breast cancer development and prognosis, and its inhibition is a potential treatment strategy.

RESULTS

In this study, we investigated the effects of prodelphinidin B-2,3,3''-O-gallate (named PB2,3,3''/OG or compound 2) via chemical oxidation of EGCG on cell viability and the Notch1 signaling pathway in breast cancer cells. We found that compound 2 showed significant cytotoxicity against triple-negative breast cancer cells, with the half maximal inhibitory concentration (IC50) values ranging 20-50 µM. In MDA-MB453 cells, compound 2 inhibited proliferation, clone formation, and the expression of proteins involved in the Notch1 signaling pathway. Furthermore, compound 2 induced cell cycle arrest and apoptosis. Consistent with the results of in-vitro experiments, treatment with compound 2 significantly reduced tumor growth. Mechanistically, compound 2 directly bound to Notch1 with high binding affinity (dissociation constant: KD=4.616 × 10- 6 M).

CONCLUSION

Our finding suggested that compound 2 may be a promising agent for the development of novel anti-cancer therapy options.

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

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

Neoadjuvant nivolumab and chemotherapy in early estrogen receptor-positive breast cancer: a randomized phase 3 trial

Patients with estrogen receptor-positive (ER+), human epidermal growth factor receptor 2-negative (HER2-) primary breast cancer (BC) have low pathological complete response (pCR) rates with neoadjuvant chemotherapy. A subset of ER+/HER2- BC contains dense lymphocytic infiltration. We hypothesized that addition of an anti-programmed death 1 agent may increase pCR rates in this BC subtype. We conducted a randomized, multicenter, double-blind phase 3 trial to investigate the benefit of adding nivolumab to neoadjuvant chemotherapy in patients with newly diagnosed, high-risk, grade 3 or 2 (ER 1 to ≤10%) ER+/HER2- primary BC. In total, 510 patients were randomized to receive anthracycline and taxane-based chemotherapy with either intravenous nivolumab or placebo. The primary endpoint of pCR was significantly higher in the nivolumab arm compared with placebo (24.5% versus 13.8%; P = 0.0021), with greater benefit observed in patients with programmed death ligand 1-positive tumors (VENTANA SP142 ≥1%: 44.3% versus 20.2% respectively). There were no new safety signals identified. Of the five deaths that occurred in the nivolumab arm, two were related to study drug toxicity; no deaths occurred in the placebo arm. Adding nivolumab to neoadjuvant chemotherapy significantly increased pCR rates in high-risk, early-stage ER+/HER2- BC, particularly among patients with higher stromal tumor-infiltrating lymphocyte levels or programmed death ligand 1 expression, suggesting a new treatment paradigm that emphasizes the role of immunotherapy and T cell immunosurveillance in luminal disease. Clinical trials.gov identifier: NCT04109066.

Unraveling complexity and leveraging opportunities in uncommon breast cancer subtypes

Special histologic subtypes of breast cancer (BC) exhibit unique phenotypes and molecular profiles with diagnostic and therapeutic implications, often differing in behavior and clinical trajectory from common BC forms. Novel methodologies, such as artificial intelligence may improve classification. Genetic predisposition plays roles in a subset of cases. Uncommon BC presentations like male, inflammatory and pregnancy-related BC pose challenges. Emerging therapeutic strategies targeting genetic alterations or immune microenvironment are being explored.

Intravenous liposomal irinotecan in metastatic triple-negative breast cancer after ≥ 2 prior lines of chemotherapy: a phase Ib study

This study (NCT04728035) aimed to explore the safety and efficacy of liposomal irinotecan (HE072) in patients with metastatic triple-negative breast cancer (mTNBC). This study consisted of two parts. In part 1, the 3 + 3 design was used to investigate three dose levels of HE072 (50, 70 and 90 mg/m2). In part 2, patients were enrolled in two cohorts (mTNBC and HER2-negative breast cancer brain metastasis [BCBM]), and received HE072 70 mg/m2 every two weeks (Q2W). The primary endpoints were maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D), and treatment emergent adverse events (TEAEs). The secondary endpoints were pharmacokinetic profiles and efficacy including objective response rate (ORR) and disease control rate (DCR) (all patients) and Central Nervous System ORR and clinical benefit rate (CBR, for patients with HER2-negative BCBM), duration of response, progression free survival (PFS), overall survival (OS). A total of 119 patients were enrolled, including 101 mTNBC and 18 HER2-negative BCBM. One dose limiting toxicity (grade 3 nausea and vomiting) occurred at 70 mg/m2, and the MTD was not reached. The most common ≥ grade 3 TEAEs related to HE072 included neutropenia (21.0%), leukopenia (18.5%), diarrhea (10.1%). Among 87 evaluable patients with mTNBC, 22 patients (25.3%) achieved overall response. The DCR was 67.8% (59/87). The median PFS and OS were 4.8 months and 14.1 months, respectively. The RP2D was 70 mg/m2 Q2W. Promising antitumor activity in heavily pre-treated patients with mTNBC was observed, which warrants further validation.

Molecular Basis of Breast Tumor Heterogeneity

Breast cancer (BC) is a profoundly heterogenous disease, with diverse molecular, histological, and clinical variations. The intricate molecular landscape of BC is evident even at early stages, illustrated by the complexity of the evolution from precursor lesions to invasive carcinoma. The key for therapeutic decision-making is the dynamic assessment of BC receptor status and clinical subtyping. Hereditary BC adds an additional layer of complexity to the disease, given that different cancer susceptibility genes contribute to distinct phenotypes and genomic features. Furthermore, the various BC subtypes display distinct metabolic demands and immune microenvironments. Finally, genotypic-phenotypic correlations in special histologic subtypes of BC inform diagnostic and therapeutic approaches, highlighting the significance of thoroughly comprehending BC heterogeneity.

Ferroptosis-targeting drugs in breast cancer

In 2020, breast cancer surpassed lung cancer as the most common cancer in the world for the first time. Due to the resistance of some breast cancer cell lines to apoptosis, the therapeutic effect of anti-breast cancer drugs is limited. According to recent report, the susceptibility of breast cancer cells to ferroptosis affects the progress, prognosis and drug resistance of breast cancer. For instance, roblitinib induces ferroptosis of trastuzumab-resistant human epidermal growth factor receptor 2 (HER2)-positive breast cancer cells by diminishing fibroblast growth factor receptor 4 (FGFR4) expression, thereby augmenting the susceptibility of these cells to HER2-targeted therapies. In tamoxifen-resistant breast cancer cells, Fascin exacerbates their resistance by repressing solute carrier family 7 member 11 (SLC7A11) expression, which in turn heightens their responsiveness to tamoxifen. In recent years, Chinese herbs extracts and therapeutic drugs have been demonstrated to elicit ferroptosis in breast cancer cells by modulating a spectrum of regulatory factors pertinent to ferroptosis, including SLC7A11, glutathione peroxidase 4 (GPX4), acyl-CoA synthetase long chain family member 4 (ACSL4), and haem oxygenase 1 (HO-1). Here, we review the roles and mechanisms of Chinese herbal extracts and therapeutic drugs in regulating ferroptosis in breast cancer, providing potential therapeutic options for anti-breast cancer.

A Microfluidic 3D-Tumor-Spheroid Model for the Evaluation of Targeted Therapies from Angiogenesis-Related Cytokines at the Single Spheroid Level

Angiogenesis is a key player in drug resistance to targeted therapies for breast cancer. The average expression of angiogenesis-related cytokines is widely associated with the treatments of target therapies for a population of cells or spheroids, overlooking the distinct responses for individuals. In this work, a highly integrated microfluidic platform is developed for the generation of monodisperse multicellular tumor spheroids (MTSs), drug treatments, and the measurement of cytokines for individual MTSs in a single chip. The platform allows the correlation evaluation between cytokine secretion and drug treatment at the level of individual spheroids. For validation, quantities of six representative proangiogenic cytokines are tested against treatments with four model drugs at varying times and concentrations. By applying a linear regression model, significant correlations are established between cytokine secretion and the treated drug concentration for individual spheroids. The proposed platform provides a high-throughput method for the investigation of the molecular mechanism of the cytokine response to targeted therapies and paves the way for future drug screening using predictive regression models at the single-spheroid level.

Impact of Neoadjuvant Therapy on PD-L1 Expression in Triple-Negative Breast Cancer and Correlation with Clinicopathological Factors

BACKGROUND

This study aims to deliver more insights on the impact of neoadjuvant treatment on Pd-L1 expression and to evaluate its correlation with clinicopathological factors.

METHODS

We reviewed 88 TNBC cases for the period 2021-2023. Data on age, tumor size, stage, and treatment were collected. Histological slides were assessed for subtype, grade, and TILs. A total of 48 received neoadjuvant treatment. HER2 and Ki67 were evaluated via immunohistochemistry. PD-L1 expression was tested on primary and residual tumors. Statistical analysis was performed using IBM SPSS (p < 0.05).

RESULTS

In this study, PD-L1 positive expression was found in 44.3% of primary tumors, with 52.9% of initially positive cases losing expression post-treatment. TILs were significantly higher in PD-L1-positive tumors (mean 41.79% vs. 27.55%, p = 0.001). A notable correlation was found between PD-L1 expression and Ki-67 proliferation index, with PD-L1-positive tumors having a median Ki-67 of 64.49 compared to 52.86 in negative cases (p = 0.015). Neoadjuvant immunotherapy led to a lower mean residual cancer burden (0.95 vs. 2.55, p = 0.002) compared to chemotherapy alone. Higher Ki-67 levels (≥50%) were associated with better treatment outcomes, showing a mean RCB score of 1.60 versus 3.16 for lower levels (p = 0.022). HER2-negative cases had a higher prevalence of favorable pathological response (54.5%) compared to HER2-low tumors (25%, p = 0.048), because of the strong correlation to high proliferative index.

CONCLUSIONS

In conclusion, PD-L1 expression in TNBC shows significant discordance post-treatment, highlighting the need for routine testing and further research on predictive biomarkers.

Towards precision medicine: design considerations for nanozymes in tumor treatment

Since the discovery of Fe3O4 nanoparticles with enzyme-like activity in 2007, nanozymes have emerged as a promising class of catalysts, offering advantages such as high catalytic efficiency, low cost, mild reaction conditions, and excellent stability. These properties make nanozymes highly suitable for large-scale production. In recent years, the convergence of nanomedicine and nanocatalysis has highlighted the potential of nanozymes in diagnostic and therapeutic applications, particularly in tumor therapy. Despite these advancements, the clinical translation of nanozymes remains hindered by the lack of designs tailored to specific tumor characteristics, limiting their effectiveness in targeted therapy. This review addresses the mechanisms by which nanozymes induce cell death in various tumor types and emphasizes the key design considerations needed to enhance their therapeutic potential. By identifying the challenges and opportunities in the field, this study aims to provide a foundation for future nanozyme development, ultimately contributing to more precise and effective cancer treatments.

GATDE: A graph attention network with diffusion-enhanced protein-protein interaction for cancer classification

Cancer classification is crucial for effective patient treatment, and recent years have seen various methods emerge based on protein expression levels. However, existing methods oversimplify by assuming uniform interaction strengths and neglecting intermediate influences among proteins. Addressing these limitations, GATDE employs a graph attention network enhanced with diffusion on protein-protein interactions. By constructing a weighted protein-protein interaction network, GATDE captures the diversity of these interactions and uses a diffusion process to assess multi-hop influences between proteins. This information is subsequently incorporated into the graph attention network, resulting in precise cancer classification. Experimental results on breast cancer and pan-cancer datasets demonstrate that GATDE surpasses current leading methods. Additionally, in-depth case studies further validate the effectiveness of the diffusion process and the attention mechanism, highlighting GATDE's robustness and potential for real-world applications.

HEBP2 affects sensitivity to cisplatin and BCNU but not to paclitaxel in MDA-MB-231 breast cancer cells

Breast cancer has the highest incidence of all cancer types in women. Triple-negative breast cancer (TNBC) accounts for 15% of all breast cancer cases and is the most aggressive type, with a poor prognosis and limited treatment. Treatment failure in patients is largely due to resistance to chemotherapy. In this study, we aimed to identify the novel factors contributing to chemoresistance in TNBC using cisplatin and 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). We found that transactivation of the heme-binding protein 2 (HEBP2) gene was common in surviving colonies of cells after exposure to two types of chemotherapeutic agents, namely cisplatin and BCNU, from genome-scale transcriptional activation library screening in the TNBC cell line MDA-MB-231. Analysis of a public database (Proteogenomic Landscape of Breast Cancer, CPTAC) indicated that HEBP2 mRNA expression was elevated in TNBC tissues compared to that in non-TNBC tissues. HEBP2 facilitates necrotic cell death under oxidative stress; however, it is not yet known whether HEBP2 affects cancer cell survival following chemotherapy. Therefore, we investigated the effects of HEBP2 expression on the sensitivity to cisplatin and BCNU in MDA-MB-231 cells. Overexpression of HEBP2 significantly enhanced the viability of MDA-MB-231 cells in response to cisplatin and BCNU, but not methyl methanesulfonate (MMS) and paclitaxel. In contrast, CRISPR/Cas9-mediated HEBP2-knockout greatly reduced cell viability in response to cisplatin and BCNU, but not to MMS and paclitaxel, in MDA-MB-231 cells. Moreover, the exogenous introduction of HEBP2 restored the resistance of HEBP2-deficient cells to cisplatin and BCNU to wild-type levels. These findings suggest that HEBP2 may play a significant role in resistance to cisplatin and BCNU, which induce intrastrand and interstrand DNA crosslinks, but not to monoalkylating or microtubule-stabilizing agents in TNBC cells. The possibility exists that HEBP2 serves as a biomarker for predicting response or a therapeutic target for overcoming resistance to platinum-based and alkylating anticancer agents in TNBC.

CK5/6 Expression in Molecular Subtypes of Invasive Ductal Carcinoma

Background Breast cancer (BC) is the leading cause of cancer-related deaths in women worldwide. There has been a significant increase in the incidence of BC in Pakistan. Family history, older age, obesity, tobacco use, oral contraceptive use, early menarche, and hormonal replacement therapy are among the major risk factors. The most common histological subtype of BC is invasive ductal carcinoma (IDC). Molecular subtypes of BC include mainly Luminal A, Luminal B, human epidermal growth factor receptor 2 (HER-2) enriched, and triple-negative BC subtypes, with the triple-negative subtype having the worst prognosis. CK5/6 serves as a basal keratin biomarker. This aimed to assess the expression of CK5/6 in IDC of the breast belonging to different molecular classes and to compare its expression with traditionally defined prognostic factors for different molecular subtypes. Methodology A cross-sectional, observational study was conducted at the Chughtai Institute of Pathology after approval from the Institutional Review Board (approval number: 1198/IRB/CIP). All cases during a period of six months (April 2023 to September 2023) were sampled using non-probability convenient sampling. All mastectomy samples diagnosed as IDC were included in the study. After standard tissue processing, paraffin tissue blocks and slides were prepared followed by hematoxylin & eosin staining. Hormonal receptors (estrogen receptor, progesterone receptor, HER-2) were assessed for cases to segregate them into molecular subtypes. CK5/6 antibody was then applied and the data were collected on a pre-designed proforma. SPSS version 25.0 (IBM Corp., Armonk, NY, USA) was used for data analysis. Results Of a total of 85 cases, 19 (22.3%) were positive for CK5/6. Of these 19 cases, the majority (68%, p = 0.001) belonged to the triple-negative class of tumors, comprising 13 cases. No case from the Luminal A class showed expression for CK5/6 stain (p = 0.028). Overall, four cases of the Luminal B subtype showed CK5/6 positivity (10.8%, p = 0.022) while two cases of the HER-2-enriched subtype were positive for the stain (33.3%, p > 0.05). These results were analyzed in relation to different prognostic factors. The majority of CK5/6-positive cases showed lymphovascular invasion (42%) and belonged to grade 3 tumors (57.8%). Conclusions The expression of CK5/6 in IDC of the breast is associated with poor prognostic factors such as triple-negative molecular subtypes, high histological grade, lymphovascular invasion, positive nodal status, and high pathological stage.

Prognostic impact of histological subtyping in triple-negative breast cancer

The impact of special histological types (ST) in triple-negative breast cancer (TNBC) and its association with overall outcome has gained increasing relevance as survival has been linked to specific histological TNBC subtypes. We evaluated the clinicopathological and survival data of 598 patients with 613 TNBCs, including 464 TNBCs of no special type (NST) and 149 TNBCs ST (low-grade, n = 12, 8.1%; high-grade, n = 112, 75.2%; apocrine and androgen receptor-positive [APO AR], n = 25, 16.8%). Patients with low-grade TNBC ST and TNBC ST APO AR were significantly older (P < 0.001) and had a lower Ki67 index (P < 0.001) than those with TNBC NST. Patients with high-grade TNBC ST were significantly older (P = 0.006) and had poorer pathological responses to neoadjuvant chemotherapy (NAC) (P < 0.001) than those with TNBC NST. Significant survival differences were observed between low-grade TNBC ST, TNBC ST APO AR, high-grade TNBC ST, and TNBC NST in the entire study group (DFS, P = 0.002; DDFS, P = 0.001) and in the non-NAC subgroup (OS, P = 0.034; DFS, P = 0.001; DDFS, P < 0.001). Patients with low-grade TNBC ST had the best survival outcomes. Patients with high-grade TNBC ST showed significantly worse outcomes than those with TNBC NST (entire study group: OS, P = 0.049; DFS, P < 0.001; DDFS, P = 0.001; non-NAC subgroup: OS, P = 0.014; DFS, P < 0.001; DDFS, P < 0.001). We conclude that prognostic stratification of TNBC ST is ultimately important for optimizing the therapeutic management of patients with these rare tumor entities.

Triple-Negative Breast Cancer: Molecular Particularities Still a Challenge

Worldwide, breast cancer (BC) is one of the most common cancers in women and is responsible for the highest number of cancer-related deaths among women, with a special clinical behavior and therapy response. Triple-negative breast cancer (TNBC) is seen as a highly invasive BC, characterized by a short survival, higher mortality, recurrence, and metastasis when it is compared to the other BC subtypes. The molecular subtyping of TNBC based on mRNA expression levels does not accurately reflect protein expression levels, which impacts targeted therapy effectiveness and prognostic predictions. Most TNBC cases exhibit a high frequency of homologous recombination (HR) DNA repair deficiency (HRD) signatures and are associated with a complex genomic profile. Biomarker research in TNBC includes investigating genetic mutations, gene expression patterns, immune system-related markers, and other factors that can provide valuable information for diagnosis, treatment selection, and patient outcomes. Additionally, these biomarkers are often crucial in the development of personalized and precision medicine approaches, where treatments are customized to each patient's unique characteristics. This ongoing research is essential for improving the management and outcomes of TNBC, which is a challenging and heterogeneous form of breast cancer. The findings of this research have practical implications for refining treatment strategies, particularly in selecting appropriate systemic therapies and integrating traditional treatment modalities like surgery and radiotherapy into comprehensive care plans for TNBC patients.

Design, synthesis, and biological evaluation of chalcone acetamide derivatives against triple negative breast cancer

Chalcones are chemical scaffolds found in natural products, particularly in plants, and are considered for structural diversity in medicinal chemistry for drug development. Herein, we designed and synthesised novel acetamide derivatives of chalcone, characterizing them using 1H NMR, 13C NMR, HRMS, and IR spectroscopic methods. These derivatives were then screened against human cancer cells for cytotoxicity using the SRB assay. Among the tested derivatives, 7g, with a pyrrolidine group, exhibited better cell growth inhibition activity against triple-negative breast cancer (TNBC) cells. Further assays, including SRB, colony formation, and fluorescent dye-based microscopic analysis, confirmed that 7g significantly inhibited MDA-MB-231 cell proliferation. Furthermore, 7g promoted apoptosis by upregulating cellular reactive oxygen species (ROS) levels and disrupting mitochondrial membrane potential (MMP). Elevated expression of pro-apoptotic proteins (Bax and caspase-3) and a higher Bax/Bcl-2 ratio with downregulation of anti-apoptotic (Bcl-2) protein levels were observed in TNBC cells. The above results suggest that 7g can promote cellular death through apoptotic mechanisms in TNBC cells.

Mechanisms of triple-negative breast cancer extravasation: Impact of the physical environment and endothelial glycocalyx

Cancer metastasis is the leading cause of death for those afflicted with cancer. In cancer metastasis, the cancer cells break off from the primary tumor, penetrate nearby blood vessels, and attach and extravasate out of the vessels to form secondary tumors at distant organs. This makes extravasation a critical step of the metastatic cascade. Herein, with a focus on triple-negative breast cancer, the role that the prospective secondary tumor microenvironment's mechanical properties play in circulating tumor cells' extravasation is reviewed. Specifically, the effects of the physically regulated vascular endothelial glycocalyx barrier element, vascular flow factors, and subendothelial extracellular matrix mechanical properties on cancer cell extravasation are examined. The ultimate goal of this review is to clarify the physical mechanisms that drive triple-negative breast cancer extravasation, as these mechanisms may be potential new targets for anti-metastasis therapy.

Integrated virtual screening and molecular dynamics simulation approaches revealed potential natural inhibitors for DNMT1 as therapeutic solution for triple negative breast cancer

Triple negative breast cancers (TNBC) are clinically heterogeneous but mostly aggressive malignancies devoid of expression of the estrogen, progesterone, and HER2 (ERBB2 or NEU) receptors. It accounts for 15-20% of all cases. Altered epigenetic regulation including DNA hypermethylation by DNA methyltransferase 1 (DNMT1) has been implicated as one of the causes of TNBC tumorigenesis. The antitumor effect of DNMT1 has also been explored in TNBC that currently lacks targeted therapies. However, the actual treatment for TNBC is yet to be discovered. This study is attributed to the identification of novel drug targets against TNBC. A comprehensive docking and simulation analysis was performed to optimize promising new compounds by estimating their binding affinity to the target protein. Molecular dynamics simulation of 500 ns well complemented the binding affinity of the compound and revealed strong stability of predicted compounds at the docked site. Calculation of binding free energies using MMPBSA and MMGBSA validated the strong binding affinity between compound and binding pockets of DNMT1. In a nutshell, our study uncovered that Beta-Mangostin, Gancaonin Z, 5-hydroxysophoranone, Sophoraflavanone L, and Dorsmanin H showed maximum binding affinity with the active sites of DNMT1. Furthermore, all of these compounds depict maximum drug-like properties. Therefore, the proposed compounds can be a potential candidate for patients with TNBC, but, experimental validation is needed to ensure their safety.Communicated by Ramaswamy H. Sarma.

Ferroptosis induction via targeting metabolic alterations in triple-negative breast cancer

Triple-negative breast cancer (TNBC), the most aggressive form of breast cancer, presents severe threats to women's health. Therefore, it is critical to find novel treatment approaches. Ferroptosis, a newly identified form of programmed cell death, is marked by the buildup of lipid reactive oxygen species (ROS) and high iron concentrations. According to previous studies, ferroptosis sensitivity can be controlled by a number of metabolic events in cells, such as amino acid metabolism, iron metabolism, and lipid metabolism. Given that TNBC tumors are rich in iron and lipids, inducing ferroptosis in these tumors is a potential approach for TNBC treatment. Notably, the metabolic adaptability of cancer cells allows them to coordinate an attack on one or more metabolic pathways to initiate ferroptosis, offering a novel perspective to improve the high drug resistance and clinical therapy of TNBC. However, a clear picture of ferroptosis in TNBC still needs to be completely revealed. In this review, we provide an overview of recent advancements regarding the connection between ferroptosis and amino acid, iron, and lipid metabolism in TNBC. We also discuss the probable significance of ferroptosis as an innovative target for chemotherapy, radiotherapy, immunotherapy, nanotherapy and natural product therapy in TNBC, highlighting its therapeutic potential and application prospects.

Secretory Breast Carcinoma: Report of Two Cases and Literature Review

Secretory Breast Carcinoma (SBC) is a rare subtype of breast cancer, predominantly affecting young women, and characterized by hormone receptor-negative and HER2-negative tumors with distinctive histological features, including secretory droplets within tumor cells. This article presents 2 unique cases of SBC, Case 1 involving a 42-year-old woman with triple-negative mammary carcinoma later diagnosed with triple-negative secretory carcinoma, and Case 2 featuring a 48-year-old woman with poorly differentiated adenocarcinoma subsequently identified as invasive mammary carcinoma of secretory type. Both cases received diverse treatment regimens, incorporating surgery, chemotherapy, radiotherapy, and hormone therapy. The importance of accurate diagnosis and the need for further research to optimize the management of this rare breast cancer subtype are emphasized. Raising awareness of SBC and reporting additional cases can enhance understanding and improve patient outcomes. Additionally, the integration of clinical, radiological, and histopathological findings, alongside specific molecular markers like S-100 and mammaglobin, is crucial for accurate SBC diagnosis. Given the lack of established guidelines for SBC management, collecting additional cases can aid in defining a more effective strategy for diagnosis, monitoring, and treatment, ultimately contributing to advancements in the field. Herein, we report 2 cases of this rare disease that were diagnosed and treated in our institution.

Nanodrug regulates ROS homeostasis via enhancing fatty acid oxidation and inhibiting autophagy to overcome tumor drug resistance

The treatment of drug-resistant tumors poses a significant challenge in the field of tumor therapy. Disrupting the homeostasis of reactive oxygen species (ROS) within tumor cells may represent a pivotal strategy for overcoming the prevalent issue of drug resistance. However, the restricted sustainability of ROS generation and the increased autophagy capacity exhibited by tumor cells hinder the application of ROS-based therapies. In this study, we developed liposome nanoparticles (Ato/CQ@L) for co-encapsulation of atorvastatin (Ato), an activator of AMP-activated protein kinase (AMPK), and chloroquine (CQ), an autophagy inhibitor. Upon internalization by tumor cells, Ato upregulated carnitine palmitoyltransferase 1(CPT1) concentration and promoted fatty acid oxidation (FAO) within the tumor cells. The process of FAO coupled with an abundance of fatty acid substrates, facilitates a sustained generation of ROS production. Concurrently, a positive feedback loop is established between escalated concentration of ROS and AMPK protein levels, resulting in a persistent elevation in ROS levels. In addition, CQ disrupted lysosomes, leading to an increased lysosomal pH and reducing autophagy in tumor cells. In both in vivo and in vitro experiments, the Ato/CQ@L treatment group exhibited a considerable enhancement in tumor cell apoptosis, validating the efficacy of this combined therapy. In summary, the combined therapy involving Ato and CQ addresses the inherent limitations of conventional ROS therapy, which include insufficient ROS production and increased autophagy. This approach holds significant potential as a treatment strategy for drug-resistant triple-negative breast cancer.

Recent progress in tannic acid based approaches as a natural polyphenolic biomaterial for cancer therapy: A review

Significant advancements have been noticed in cancer therapy for decades. Despite this, there are still many critical challenges ahead, including multidrug resistance, drug instability, and side effects. To overcome obstacles of these problems, various types of materials in biomedical research have been explored. Chief among them, the applications of natural compounds have grown rapidly due to their superb biological activities. Natural compounds, especially polyphenolic compounds, play a positive and great role in cancer therapy. Tannic acid (TA), one of the most famous polyphenols, has attracted widespread attention in the field of cancer treatment with unique structural, physicochemical, pharmaceutical, anticancer, antiviral, antioxidant and other strong biological features. This review concentrated on the basic structure along with the important role of TA in tuning oncological signal pathways firstly, and then focused on the use of TA in chemotherapy and preparation of delivery systems including nanoparticles and hydrogels for cancer therapy. Besides, the application of TA/Fe3+ complex coating in photothermal therapy, chemodynamic therapy, combined therapy and theranostics is discussed.

Effects of Hyaluronan on Breast Cancer Aggressiveness

The expression of the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) in breast cancer cells is critical for determining tumor aggressiveness and targeting therapies. The presence of such receptors allows for the use of antagonists that effectively reduce breast cancer growth and dissemination. However, the absence of such receptors in triple-negative breast cancer (TNBC) reduces the possibility of targeted therapy, making these tumors very aggressive with a poor outcome. Cancers are not solely composed of tumor cells, but also include several types of infiltrating cells, such as fibroblasts, macrophages, and other immune cells that have critical functions in regulating cancer cell behaviors. In addition to these cells, the extracellular matrix (ECM) has become an important player in many aspects of breast cancer biology, including cell growth, motility, metabolism, and chemoresistance. Hyaluronan (HA) is a key ECM component that promotes cell proliferation and migration in several malignancies. Notably, HA accumulation in the tumor stroma is a negative prognostic factor in breast cancer. HA metabolism depends on the fine balance between HA synthesis by HA synthases and degradation yielded by hyaluronidases. All the different cell types present in the tumor can release HA in the ECM, and in this review, we will describe the role of HA and HA metabolism in different breast cancer subtypes.

YAP transduction drives triple-negative breast cancer aggressiveness through modulating the EGFR‒AKT axis in patient-derived xenograft cells

Aside from the high prevalence of incidents of breast cancer, the high grade of heterogeneity and the dearth of standard treatment guidelines make triple-negative breast cancer (TNBC) the most refractory subtype. Though still in its infancy, the Hippo pathway has been known to play a critical role in tumorigenesis. However, the molecular mechanics through which the pathway exploits the breast cancer (BC) cell vulnerability are largely unexplored. In this study, we observed a relatively higher expression of the Hippo effector, yes-associated protein (YAP), in TNBC patients compared to non-TNBC patients. Thus, we sought to investigate the contribution of Hippo signaling in TNBC by focusing particularly on transducers of the pathway. Impeding YAP transactivation by means of RNA interference or pharmacological inhibition was carried out, followed by evaluation of the subsequent biological changes at the molecular level. We successfully translated the observed data into a TNBC patient-derived xenograft cell line (PDXC). We discovered that nuclear translocation of YAP was associated with TNBC aggressive characteristics and activated the EGFR-AKT axis. Here, we explored the putative role of the Hippo transducer in enhancing cancer hostility and observed that YAP transduction drives proliferation, migration, and survival of TNBC by preventing cellular apoptosis through mediating EGFR activation. These observations suggest that YAP represents a major vulnerability in TNBC cells that may be exploited therapeutically.

Surface roughness modulates EGFR signaling and stemness of triple-negative breast cancer cells

Introduction: Cancer stem cells (CSC), a major culprit of drug-resistant phenotypes and tumor relapse, represent less than 2 % of the bulk of TNBC cells, making them difficult to isolate, study, and thus, limiting our understanding of the pathogenesis of the disease. Current methods for CSC enrichment, such as 3D spheroid culture, genetic modification, and stem cell conditioning, are time consuming, expensive, and unsuitable for high-throughput assays. One way to address these limitations is to use topographical stimuli to enhance CSC populations in planar culture. Physical cues in the breast tumor microenvironment can influence cell behavior through changes in the mechanical properties of the extracellular matrix (ECM). In this study, we used topographical cues on polystyrene films to investigate their effect on the proteome and stemness of standard TNBC cell lines. Methods: The topographical polystyrene-based array was generated using razor printing and polishing methods. Proteome data were analyzed and enriched bioprocesses were identified using R software. Stemness was assessed measuring CD44, CD24 and ALDH markers using flow cytometry, immunofluorescence, detection assays, and further validated with mammosphere assay. EGF/EGFR expression and activity was evaluated using enzyme-linked immunosorbent assay (ELISA), immunofluorescence and antibody membrane array. A dose-response assay was performed to further investigate the effect of surface topography on the sensitivity of cells to the EGFR inhibitor. Results: Surface roughness enriched the CSC population and modulated epidermal growth factor receptor (EGFR) signaling activity in TNBC cells. Enhanced proliferation of MDA-MB-468 cells in roughness correlated with upregulation of the epidermal growth factor (EGF) ligand, which in turn corresponded with a 3-fold increase in the expression of EGFR and a 42% increase in its phosphorylation compared to standard smooth culture surfaces. The results also demonstrated that phenotypic changes associated with topographical (roughness) stimuli significantly decreased the drug sensitivity to the EGFR inhibitor gefitinib. In addition, the proportion of CD44+/CD24-/ALDH+ was enhanced on surface roughness in both MDA-MB-231 and MDA-MB-468 cell lines. We also demonstrated that YAP/TAZ activation decreased in a roughness-dependent manner, confirming the mechanosensing effect of the topographies on the oncogenic activity of the cells. Discussion: Overall, this study demonstrates the potential of surface roughness as a culture strategy to influence oncogenic activity in TNBC cells and enrich CSC populations in planar cultures. Such a culture strategy may benefit high-throughput screening studies seeking to identify compounds with broader tumor efficacy.

Dynamic tumor microenvironment, molecular heterogeneity, and distinct immunologic portrait of triple-negative breast cancer: an impact on classification and treatment approaches

Heterogeneity of the tumor microenvironment (TME) and the lack of a definite targetable receptor in triple-negative breast cancer (TNBC) has carved a niche for this cancer as a particularly therapeutically challenging form of breast cancer. However, recent advances in high-throughput genomic analysis have provided new insights into the unique microenvironment and defining characteristics of various subsets of TNBC. This improved understanding has contributed to the development of novel therapeutic strategies including targeted therapies such as PARP inhibitors and CDK inhibitors. Moreover, the recent FDA approval of the immune checkpoint inhibitor against programmed cell death protein 1 (PD-1), pembrolizumab and atezolizumab, holds the promise of improving the quality of life and increasing the overall survival of TNBC patients. This recent approval is one of the many therapeutically novel strategies that are currently being exploited in clinical trials toward eventual contribution to the oncologist's toolbox against TNBC. In this review, we comprehensively discuss TNBC's distinct TME and its immunophenotype. Furthermore, we highlight the histological and molecular classification of this cancer. More importantly, we describe how these characteristics and classifications contribute to the current standards of care and how they steer the development of newer and more targeted therapies toward achieving peak therapeutic goals in the treatment of TNBC.

Glycosylated proteins with abnormal glycosylation changes are potential biomarkers for early diagnosis of breast cancer

Conventional cancer management relies on tumor type and stage for diagnosis and treatment, which leads to recurrence and metastasis and death in young women. Early detection of proteins in the serum aids diagnosis, progression, and clinical outcomes, possibly improving survival rate of breast cancer patients. In this review, we provided an insight into the influence of aberrant glycosylation on breast cancer development and progression. Examined literatures revealed that mechanisms underlying glycosylation moieties alteration could enhance early detection, monitoring, and therapeutic efficacy in breast cancer patients. This would serve as a guide for the development of new serum biomarkers with higher sensitivity and specificity, providing possible serological biomarkers for breast cancer diagnosis, progression, and treatment.

Molecular Classification of Breast Cancer: Relevance and Challenges

CONTEXT.—

Appropriate patient management requires precise and meaningful tumor classification. Breast cancer classification continues to evolve from traditional morphologic evaluation to more sophisticated systems with the integration of new knowledge from research being translated into practice. Breast cancer is heterogeneous at the molecular level, with diversified patterns of gene expression, which is presumably responsible for the difference in tumor behavior and prognosis. Since the beginning of this century, new molecular technology has been gradually applied to breast cancer research on issues pertinent to prognosis (prognostic signature) and therapeutic prediction (predictive signature), and much progress has been made.

OBJECTIVE.—

To summarize the current state and the prospective future of molecular classification of breast cancer.

DATA SOURCES.—

Sources include recent medical literature on molecular classification of breast cancer.

CONCLUSIONS.—

Identification of intrinsic tumor subtypes has set a foundation for refining the breast cancer molecular classification. Studies have explored the genetic features within the intrinsic cancer subtypes and have identified novel molecular targets that led to the innovation of clinical assays to predict a patient's prognosis and to provide specific guidelines for therapeutic decisions. With the development and implication of these molecular tools, we have remarkably advanced our knowledge and enhanced our power to provide optimal management to patients. However, challenges still exist. Besides accurate prediction of prognosis, we are still in urgent need of more molecular predictors for tumor response to therapeutic regimes. Further exploration along this path will be critical for improving a patient's prognosis.

'Why is survival with triple negative breast cancer so low? insights and talking points from preclinical and clinical research'

INTRODUCTION

Triple negative breast cancer is typically related to poor prognosis, early metastasis, and high recurrence rate. Intrinsic and extrinsic biological features of TNBC and resistance mechanisms to conventional therapies can support its aggressive behavior, characterizing TNBC how extremely heterogeneous. Novel combination strategies are under investigation, including immunotherapeutic agents, anti-drug conjugates, PARP inhibitors, and various targeting agents, exploring, in the meanwhile, possible predictive biomarkers to correctly select patients for the optimal treatment for their specific subtype.

AREAS COVERED

This article examines the main malignity characteristics across different subtype, both histological and molecular, and the resistance mechanisms, both primary and acquired, to different drugs explored in the landscape of TNBC treatment, that lead TNBC to still has high mortality rate.

EXPERT OPINION

The complexity of TNBC is not only the main reason of its aggressivity, but its heterogeneity should be exploited in terms of therapeutics opportunities, combining agents with different mechanism of action, after a correct selection by biologic or molecular biomarkers. The main goal is to understand what TNBC really is and to act selectively on its characteristics, with a personalized anticancer treatment.

Triple negative breast cancer: Pitfalls and progress

Triple negative breast cancer (TNBC) is characterized by the lack of estrogen and progesterone receptor expression and lacks HER2 overexpression or gene amplification. It accounts for 10–15% of incident breast cancers and carries the worst prognosis. TNBC is overrepresented among Black and pre-menopausal women and is associated with significant psychological and treatment-related burdens, including financial toxicity. Like other breast cancers, TNBC is biologically heterogeneous, leading to diverse clinical and epidemiological behaviors, however, unlike the other clinical subtypes, in TNBC we still lack tumor-specific targeted therapy. Early TNBC outcomes have improved due to the intensification of therapies, including improvements in polychemotherapy and the addition of immunotherapy. Future efforts are needed to identify targetable aberrations for specific drug therapy, prevent immune evasion, and increase social-economic support. Given that the name TNBC illustrates its lack of specifically targeted and effective therapy, we look forward to being able to retire the name in favor of a group of targetable entities within what is now called “TNBC”.

Triple negative breast cancer: approved treatment options and their mechanisms of action

PURPOSE

Breast cancer, the most prevalent cancer worldwide, consists of 4 main subtypes, namely, Luminal A, Luminal B, HER2-positive, and Triple-negative breast cancer (TNBC). Triple-negative breast tumors, which do not express estrogen, progesterone, and HER2 receptors, account for approximately 15-20% of breast cancer cases. The lack of traditional receptor targets contributes to the heterogenous, aggressive, and refractory nature of these tumors, resulting in limited therapeutic strategies.

METHODS

Chemotherapeutics such as taxanes and anthracyclines have been the traditional go to treatment regimens for TNBC patients. Paclitaxel, docetaxel, doxorubicin, and epirubicin have been longstanding, Food and Drug Administration (FDA)-approved therapies against TNBC. Additionally, the FDA approved PARP inhibitors such as olaparib and atezolizumab to be used in combination with chemotherapies, primarily to improve their efficiency and reduce adverse patient outcomes. The immunotherapeutic Keytruda was the latest addition to the FDA-approved list of drugs used to treat TNBC.

RESULTS

The following review aims to elucidate current FDA-approved therapeutics and their mechanisms of action, shedding a light on the various strategies currently used to circumvent the treatment-resistant nature of TNBC cases.

CONCLUSION

The recent approval and use of therapies such as Trodelvy, olaparib and Keytruda has its roots in the development of an understanding of signaling pathways that drive tumour growth. In the future, the emergence of novel drug delivery methods may help increase the efficiency of these therapies whiel also reducing adverse side effects.

Luminal androgen receptor (LAR) subtype of triple-negative breast cancer: molecular, morphological, and clinical features

According to the classification presented by Lehmann BD (2016), triple-negative breast cancer (TNBC) is a heterogeneous group of malignant tumors with four specific subtypes: basal-like (subtype 1 and subtype 2), mesenchymal, and luminal androgen receptor (LAR) subtypes. The basal-like subtypes of carcinomas predominate in this group, accounting for up to 80% of all cases. Despite the significantly lower proportions of mesenchymal and LAR variants in the group of breast carcinomas with a TNBC profile, such tumors are characterized by aggressive biological behavior. To this end, the LAR subtype is of particular interest, since the literature on such tumors presents different and even contradictory data concerning the disease course and prognosis. This review is devoted to the analysis of the relevant literature, reflecting the main results of studies on the molecular properties and clinical features of the disease course of LAR-type TNBC carcinomas.

Precision Breast Cancer Medicine: Early Stage Triple Negative Breast Cancer-A Review of Molecular Characterisation, Therapeutic Targets and Future Trends

Personalised approaches to the management of all solid tumours are increasing rapidly, along with wider accessibility for clinicians. Advances in tumour characterisation and targeted therapies have placed triple-negative breast cancers (TNBC) at the forefront of this approach. TNBC is a highly heterogeneous disease with various histopathological features and is driven by distinct molecular alterations. The ability to tailor individualised and effective treatments for each patient is of particular importance in this group due to the high risk of distant recurrence and death. The mainstay of treatment across all subtypes of TNBC has historically been cytotoxic chemotherapy, which is often associated with off-target tissue toxicity and drug resistance. Neoadjuvant chemotherapy is commonly used as it allows close monitoring of early treatment response and provides valuable prognostic information. Patients who achieve a complete pathological response after neoadjuvant chemotherapy are known to have significantly improved long-term outcomes. Conversely, poor responders face a higher risk of relapse and death. The identification of those subgroups that are more likely to benefit from breakthroughs in the personalised approach is a challenge of the current era where several targeted therapies are available. This review presents an overview of contemporary practice, and promising future trends in the management of early TNBC. Platinum chemotherapy, DNA damage response (DDR) inhibitors, immune checkpoint inhibitors, inhibitors of the PI3K-AKT-mTOR, and androgen receptor (AR) pathways are some of the increasingly studied therapies which will be reviewed. We will also discuss the growing evidence for less-developed agents and predictive biomarkers that are likely to contribute to the forthcoming advances in this field. Finally, we will propose a framework for the personalised management of TNBC based upon the integration of clinico-pathological and molecular features to ensure that long-term outcomes are optimised.

Clinical implications of lipid peroxides levels in plasma and tumor tissue in breast cancer patients

Oxidative stress can promote the oxidation of lipoproteins and polyunsaturated fatty acids present in cell membranes; an event known as lipid peroxidation (LPO). LPO has been associated with carcinogenesis and cancer progression, however, its meaning concerning the clinicopathological aspects of human breast cancer is not clear. This study investigated LPO profiles in tumor and plasma samples from breast cancer patients (n = 140) considering their clinicopathological features (age at diagnosis, menopausal status, body mass index, tumor histological grade, tumor size, ki-67 proliferation index, presence of metastasis, chemotherapy response, the molecular subtype of cancer and overall survival status). LPO levels were estimated by tert-butyl hydroperoxide-initiated chemiluminescence. High LPO levels were found regarding poor prognosis parameters as young age at diagnosis (p = 0.006 in tissue), premenopausal patients (p = 0.012 in tissue), high-grade tumors (p = 0.010 in tissue and p = 0.002 in plasma), metastatic disease (p = 0.046 in tissue), chemoresistant tumors (p = 0.041 in tissue), disease relapse (p = 0.018 in tissue and p = 0.009 in plasma) and overall survival status (p = 0.001 in plasma). Our findings point out the clinical meaning of LPO and highlight it as an oxidative stress event linked to poor prognosis and disease aggressiveness in breast cancer patients.

Structure-guided design and development of cyclin-dependent kinase 4/6 inhibitors: A review on therapeutic implications

Cyclin-dependent kinase 6 (EC 2.7.11.22) play significant roles in numerous biological processes and triggers cell cycle events. CDK6 controlled the transcriptional regulation. A dysregulated function of CDK6 is linked with the development of progression of multiple tumor types. Thus, it is considered as an effective drug target for cancer therapy. Based on the direct roles of CDK4/6 in tumor development, numerous inhibitors developed as promising anti-cancer agents. CDK4/6 inhibitors regulate the G1 to S transition by preventing Rb phosphorylation and E2F liberation, showing potent anti-cancer activity in several tumors, including HR+/HER2- breast cancer. CDK4/6 inhibitors such as abemaciclib, palbociclib, and ribociclib, control cell cycle, provoke cell senescence, and induces tumor cell disturbance in pre-clinical studies. Here, we discuss the roles of CDK6 in cancer along with the present status of CDK4/6 inhibitors in cancer therapy. We further discussed, how structural features of CDK4/6 could be implicated in the design and development of potential anti-cancer agents. In addition, the therapeutic potential and limitations of available CDK4/6 inhibitors are described in detail. Recent pre-clinical and clinical information for CDK4/6 inhibitors are highlighted. In addition, combination of CDK4/6 inhibitors with other drugs for the therapeutic management of cancer are discussed.

Lipid-associated macrophages are induced by cancer-associated fibroblasts and mediate immune suppression in breast cancer

Tumor-associated macrophages (TAM) play a detrimental role in triple-negative breast cancer (TNBC). In-depth analysis of TAM characteristics and interactions with stromal cells, such as cancer-associated fibroblast (CAF), could provide important biological and therapeutic insights. Here we identify at the single-cell level a monocyte-derived-STAB1+TREM2high lipid-associated macrophage (LAM) subpopulation with immune suppressive capacities that is expanded in patients resistant to immune checkpoint blockade (ICB). Genetic depletion of this LAM subset in mice suppressed TNBC tumor growth. Flow cytometry and bulk-RNA sequencing data demonstrated that co-culture with TNBC-derived CAFs led to reprogramming of blood monocytes towards immune suppressive STAB1+TREM2high LAMs, which inhibit T cell activation and proliferation. Cell-to-cell interaction modeling and assays in vitro demonstrated the role of the inflammatory CXCL12-CXCR4 axis in CAF-myeloid cell crosstalk and recruitment of monocytes in tumor sites. Altogether, these data suggest an inflammation model whereby monocytes recruited to the tumor via the CAF-driven CXCL12-CXCR4 axis acquire pro-tumorigenic LAM capacities to support an immunosuppressive microenvironment.

Integrated analysis reveals the molecular features of fibrosis in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is an aggressive type of breast cancer. High fibrosis, marked by increased collagen fibers, is widespread in TNBC and correlated with tumor progression. However, the molecular features of fibrosis and why it results in a poor prognosis remain poorly understood. Based on multiomics datasets of TNBC, we evaluated the pathological fibrosis grade of 344 samples for further analysis. Genomic, transcriptomic, and immune changes were analyzed among different subgroups of fibrosis. High fibrosis was an independent adverse prognosis predictor and had interactions with low stromal tumor-infiltrating lymphocytes. Genomic analysis identified copy number gains of 6p22.2-6p22.1 (TRIM27) and 20q13.33 (CDH4) as genomic hallmarks of tumors with high fibrosis. Transcriptome analysis revealed the transforming growth factor-beta pathway and hypoxia pathway were key pro-oncogenic pathways in tumors with high fibrosis. Moreover, we systematically evaluate the relationship between fibrosis and different kinds of immune and stromal cells. Tumors with high fibrosis were characterized by an immunosuppressive tumor microenvironment with limited immune cell infiltration and increased fibroblasts. This study proposes new insight into the genomic and transcriptomic alterations potentially driving fibrosis. Moreover, fibrosis is related to an immunosuppressive tumor microenvironment that contributes to the poor prognosis.

Breast Cancer Subtype-Specific miRNAs: Networks, Impacts, and the Potential for Intervention

The regulatory and functional roles of non-coding RNAs are increasingly demonstrated as critical in cancer. Among non-coding RNAs, microRNAs (miRNAs) are the most well-studied with direct regulation of biological signals through post-transcriptional repression of mRNAs. Like the transcriptome, which varies between tissue type and disease condition, the miRNA landscape is also similarly altered and shows disease-specific changes. The importance of individual tumor-promoting or suppressing miRNAs is well documented in breast cancer; however, the implications of miRNA networks is less defined. Some evidence suggests that breast cancer subtype-specific cellular effects are influenced by distinct miRNAs and a comprehensive network of subtype-specific miRNAs and mRNAs would allow us to better understand breast cancer signaling. In this review, we discuss the altered miRNA landscape in the context of breast cancer and propose that breast cancer subtypes have distinct miRNA dysregulation. Further, given that miRNAs can be used as diagnostic and/or prognostic biomarkers, their impact as novel targets for subtype-specific therapy is also possible and suggest important implications for subtype-specific miRNAs.

Depletion of CCN1/CYR61 reduces triple-negative/basal-like breast cancer aggressiveness

Triple-negative/basal-like breast cancer (BC) is characterized by aggressive biological features, which allow relapse and metastatic spread to occur more frequently than in hormone receptor-positive (luminal) subtypes. The molecular complexity of triple-negative/basal-like BC poses major challenges for the implementation of targeted therapies, and chemotherapy remains the standard approach at all stages. The matricellular protein cysteine-rich angiogenic inducer 61 (CCN1/CYR61) is associated with aggressive metastatic phenotypes and poor prognosis in BC, but it is unclear whether anti-CCN1 approaches can be successfully applied in triple-negative/basal-like BC. Herein, we first characterized the prevalence of CNN1 expression in matched samples of primary tumors and metastatic relapse in a series of patients with BC. We then investigated the biological effect of CCN1 depletion on tumorigenic traits in vitro and in vivo using archetypal TNBC cell lines. Immunohistochemical analyses of tissue microarrays revealed a significant increase of the highest CCN1 score in recurrent tissues of triple-negative/basal-like BC tumors. Stable silencing of CCN1 in triple-negative/basal-like BC cells promoted a marked reduction in the expression of the CCN1 integrin receptor αvβ3, inhibited anchorage-dependent cell growth, reduced clonogenicity, and impaired migration capacity. In an orthotopic model of triple-negative/basal-like BC, silencing of CCN1 notably reduced tumor burden, which was accompanied by decreased microvessel density and concurrent induction of the luminal epithelial marker E-cadherin. Thus, CNN1/CYR61-targeting strategies might have therapeutic value in suppressing the biological aggressiveness of triple-negative/basal-like BC.

Pathogenesis of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) encompasses a heterogeneous group of fundamentally different diseases with different histologic, genomic, and immunologic profiles, which are aggregated under this term because of their lack of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 expression. Massively parallel sequencing and other omics technologies have demonstrated the level of heterogeneity in TNBCs and shed light into the pathogenesis of this therapeutically challenging entity in breast cancer. In this review, we discuss the histologic and molecular classifications of TNBC, the genomic alterations these different tumor types harbor, and the potential impact of these alterations on the pathogenesis of these tumors. We also explore the role of the tumor microenvironment in the biology of TNBCs and its potential impact on therapeutic response. Dissecting the biology and understanding the therapeutic dependencies of each TNBC subtype will be essential to delivering on the promise of precision medicine for patients with triple-negative disease.

Chemotherapy Effect on Estradiol Levels in Patients with Triple-negative Breast Cancer: A Clinical Prospective Study from Indonesia

Research Background: This study aimed to scrutinize the chemotherapy’s effect on estradiol levels in patients with triple-negative breast cancer (TNBC) at low-resource country. Methods: This prospective analytic observational cohort study involved patients with TNBC who had undergone surgery and had never received chemotherapy or hormonal therapy before. Patients were checked for estradiol levels before and after chemotherapy. This study was conducted at the Surgical Oncology Department of Regional Public Hospital Dr. Moewardi, Surakarta Indonesia, from April 2020 to March 2021. Descriptive data were presented in a frequency table based on age, menopausal status, parity status, breastfeeding status, hormonal contraception, hormonal contraception duration, family history, stage, and histological grade. Differences in estradiol changes before and after chemotherapy (mean+sd) were then reported. Results: From a total of 23 patients, 21 patients (91.3%) experienced a decrease in estradiol levels, while two patients (8.7%) underwent an increase in serum estradiol levels after chemotherapy. The mean decrease was 11.57 pg/ml. The two samples that experienced an increase in estradiol levels had a mean increase of 16.5 pg/ml. There was a significant difference between estradiol levels before and after undergoing chemotherapy, with p-value=0.001. Conclusions: In this research, chemotherapy reduced estradiol levels in TNBC patients. Statistically significant reductions in estradiol levels were based on the disease stage.

Low-grade triple-negative breast carcinomas. A report of 2 cases and an update of current concepts

Triple negative breast cancer is defined by the lack of expression of estrogen, progesterone and HER2 receptors. Significant molecular, morphological and clinical heterogeneity is present in this group of neoplasms. Although the majority are high-grade tumors, low-grade triple negative breast cancers can occur and their evolution, molecular characteristics and therapeutic management vary from the former. In the current review, we focus on the histological and immunohistochemical phenotypes of two new low-grade cases: an acinic cell carcinoma and an adenoid cystic carcinoma. Data originated from the pathology department of a third-level hospital over an 18-month period, within a breast cancer screening program. Low-grade triple negative cancers should be suspected in triple negative breast cancers with low proliferative rates as, unlike high-grade tumors, they require a multidisciplinary approach. They can be diagnosed at an early stage by immunohistochemistry using core needle biopsy.