Triple-negative breast cancer: is there a treatment on the horizon?

Electroporation enhances cell death in 3D scaffold-based MDA-MB-231 cells treated with metformin

Triple-negative breast cancer (TNBC), the most aggressive subtype of breast cancer lacks estrogen, progesterone, and HER2 receptors and hence, is therapeutically challenging. Towards this, we studied an alternate therapy by repurposing metformin (FDA-approved type-2 diabetic drug with anticancer properties) in a 3D-scaffold culture, with electrical pulses. 3D cell culture was used to simulate the tumor microenvironment more closely and MDA-MB-231, human TNBC cells, treated with both 5 mM metformin (Met) and 8 electrical pulses at 2500 V/cm, 10 µs (EP1) and 800 V/cm, 100 µs (EP2) at 1 Hz were studied in 3D and 2D. They were characterized using cell viability, reactive oxygen species (ROS), glucose uptake, and lactate production assays at 24 h. Cell viability, as low as 20 % was obtained with EP1 + 5 mM Met. They exhibited 1.65-fold lower cell viability than 2D with EP1 + 5 mM Met. ROS levels indicated a 2-fold increase in oxidative stress for EP1 + 5 mM Met, while the glucose uptake was limited to only 9 %. No significant change in the lactate production indicated glycolytic arrest and a non-conducive environment for MDA-MB-231 growth. Our results indicate that 3D cell culture, with a more realistic tumor environment that enhances cell death using metformin and electrical pulses could be a promising approach for TNBC therapeutic intervention studies.

Multiparametric MRI-based radiomic models for early prediction of response to neoadjuvant systemic therapy in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is often treated with neoadjuvant systemic therapy (NAST). We investigated if radiomic models based on multiparametric Magnetic Resonance Imaging (MRI) obtained early during NAST predict pathologic complete response (pCR). We included 163 patients with stage I-III TNBC with multiparametric MRI at baseline and after 2 (C2) and 4 cycles of NAST. Seventy-eight patients (48%) had pCR, and 85 (52%) had non-pCR. Thirty-six multivariate models combining radiomic features from dynamic contrast-enhanced MRI and diffusion-weighted imaging had an area under the receiver operating characteristics curve (AUC) > 0.7. The top-performing model combined 35 radiomic features of relative difference between C2 and baseline; had an AUC = 0.905 in the training and AUC = 0.802 in the testing set. There was high inter-reader agreement and very similar AUC values of the pCR prediction models for the 2 readers. Our data supports multiparametric MRI-based radiomic models for early prediction of NAST response in TNBC.

Multifaceted role of phytoconstituents based nano drug delivery systems in combating TNBC: A paradigm shift from chemical to natural

Triple negative breast cancer is considered to be a malignancy of grave concern with limited routes of treatment due to the absence of specific breast cancer markers and ambiguity of other potential drug targets. Poor prognosis and inadequate survival rates have prompted further research into the understanding of the molecular pathophysiology and targeting of the disease. To overcome the recurrence and resistance mechanisms of the TNBC cells, various approaches have been devised, and are being continuously evaluated to enhance their efficacy and safety. Chemo-Adjuvant therapy is one such treatment modality being employed to improve the efficiency of standard chemotherapy. Combining chemo-adjuvant therapy with other upcoming approaches of cancer therapeutics such as phytoconstituents and nanotechnology has yielded promising results in the direction of improving the prognosis of TNBC. Numerous nanoformulations have been proven to substantially enhance the specificity and cellular uptake of drugs by cancer cells, thus reducing the possibility of unintended systemic side effects within cancer patients. While phytoconstituents offer a wide variety of beneficial active constituents useful in cancer therapeutics, most favorable outcomes have been observed within the scope of polyphenols, isoquinoline alkaloids and isothiocyanates. With an enhanced understanding of the molecular mechanisms of TNBC and the advent of newer targeting technologies and novel phytochemicals of medicinal importance, a new era of cancer theranostic treatments can be explored. This review hopes to instantiate the current body of research regarding the role of certain phytoconstituents and their potential nanoformulations in targeting specific TNBC pathways for treatment and diagnostic purposes.

In silico fragment-based discovery of CIB1-directed anti-tumor agents by FRASE-bot

Chemical probes are an indispensable tool for translating biological discoveries into new therapies, though are increasingly difficult to identify since novel therapeutic targets are often hard-to-drug proteins. We introduce FRASE-based hit-finding robot (FRASE-bot), to expedite drug discovery for unconventional therapeutic targets. FRASE-bot mines available 3D structures of ligand-protein complexes to create a database of FRAgments in Structural Environments (FRASE). The FRASE database can be screened to identify structural environments similar to those in the target protein and seed the target structure with relevant ligand fragments. A neural network model is used to retain fragments with the highest likelihood of being native binders. The seeded fragments then inform ultra-large-scale virtual screening of commercially available compounds. We apply FRASE-bot to identify ligands for Calcium and Integrin Binding protein 1 (CIB1), a promising drug target implicated in triple negative breast cancer. FRASE-based virtual screening identifies a small-molecule CIB1 ligand (with binding confirmed in a TR-FRET assay) showing specific cell-killing activity in CIB1-dependent cancer cells, but not in CIB1-depletion-insensitive cells.

Vitamin D receptor polymorphisms and associated miRNAs in the development of breast cancer in African American women

Breast cancer (BCa) is a prevalent form of cancer in women, exhibiting varying rates and distribution across different ethnic groups. Among these groups, African American (AA) women have the highest incidence of BCa and the lowest levels of Vitamin D (VD). Numerous studies have explored the connection between variations in the VDR gene and BCa risk, particularly in different populations, but research on the AA population remains limited. Epigenetic modifications, including specific microRNAs (miRNAs), can influence gene expression without altering the genetic code and have been implicated in cancer initiation and progression. Our hypothesis suggests that VDR gene variations may increase BCa risk in AA women and that changes in miRNA expression profiles could contribute to BCa development. Using data from the 1000 Genome Project, we identified five VDR gene variants with significant frequency differences between AA and European-American (EA) populations. We genotyped 404 African American BCa cases and controls for five variants using TaqMan® assays. SNPstats assessed their association with BCa risk. The rs1544410 variant's recessive model (A/A) showed a decreased BCa risk in AA (odds ratio 0.33, 95% CI: 0.15-0.73, p-value 0.0041). Conversely, the rs2853563 variant's recessive model (A/A) was linked to an increased BCa risk (odds ratio 4.04, 95% CI: 1.49-10.95, p-value 0.0022). We investigated miRNA expression influenced by VD in HCC1806 Triple-Negative Breast Cancer (TNBC) cell lines with the A/A allele for rs2853563. nCounter® Nanostring technology assessed miRNA profiles after calcitriol treatment. Our results indicated that calcitriol treatment led to reduced expression of six miRNAs, four of which are associated with tumor suppression in the presence of the AA genotype in TNBC cell lines. These findings suggest that specific VDR genotypes could have a potential effect on the miRNAs expression which could potentially serve as markers for cell proliferation in TNBC.

The therapeutic effect of traditional Chinese medicine on breast cancer through modulation of the Wnt/β-catenin signaling pathway

Breast cancer, the most prevalent malignant tumor among women globally, is significantly influenced by the Wnt/β-catenin signaling pathway, which plays a crucial role in its initiation and progression. While conventional chemotherapy, the standard clinical treatment, suffers from significant drawbacks like severe side effects, high toxicity, and limited prognostic efficacy, Traditional Chinese Medicine (TCM) provides a promising alternative. TCM employs a multi-targeted therapeutic approach, which results in fewer side effects and offers a high potential for effective treatment. This paper presents a detailed analysis of the therapeutic impacts of TCM on various subtypes of breast cancer, focusing on its interaction with the Wnt/β-catenin signaling pathway. Additionally, it explores the effectiveness of both monomeric and compound forms of TCM in the management of breast cancer. We also discuss the potential of establishing biomarkers for breast cancer treatment based on key proteins within the Wnt/β-catenin signaling pathway. Our aim is to offer new insights into the prevention and treatment of breast cancer and to contribute to the standardization of TCM.

Multifaceted antineoplastic curative potency of novel water-soluble methylimidazole-based oxidovanadium (IV) complex against triple negative mammary carcinoma

A bunch of complexes harboring vanadium as metal centers have been reported to exhibit a wide array of antineoplastic properties that come under non‑platinum metallodrug series and emerge to offer alternative therapeutic strategies from the mechanistic behaviors of platinum-drugs. Though antineoplastic activities of vanado-complexes have been documented against several animal and xenografted human cancers, the definite mechanism of action is yet to unveil. In present study, a novel water soluble 1-methylimidazole substituted mononuclear dipicolinic acid based oxidovanadium (IV) complex (OVMI) has been evaluated for its antineoplastic properties in breast carcinoma both in vitro and in vivo. OVMI has been reported to generate cytotoxicity in human triple negative breast carcinoma cells, MDA-MB-231 as well as in mouse 4T1 cells by priming them for apoptosis. ROS-mediated, mitochondria-dependent as well as ER-stress-evoked apoptotic death seemed to be main operational hub guiding the cytotoxicity of OVMI in vitro. Moreover, OVMI has been noticed to elicit antimetastatic effect in vitro. Therapeutic application of OVMI has been extended on 4T1-based mammary tumor of female Balb/c mice, where it has been found to reduce tumor size, volume and restore general tissue architecture successfully to a great extent. Apart from that, OVMI has been documented to limit 4T1-based secondary pulmonary metastasis along with being non-toxic and biocompatible in vivo.

Contribution of tumour and immune cells to PD-L1 expression as a predictive biomarker in metastatic triple-negative breast cancer: exploratory analysis from KEYNOTE-119

The efficacy of pembrolizumab monotherapy versus chemotherapy increased with increasing programmed death ligand 1 (PD-L1) expression, as quantified by combined positive score (CPS; PD-L1 expression on both tumour cells and immune cells) in patients with previously treated metastatic triple-negative breast cancer (mTNBC) in the phase 3 KEYNOTE-119 study. This exploratory analysis was conducted to determine whether the expression of PD-L1 on tumour cells contributes to the predictive value of PD-L1 CPS in mTNBC. PD-L1 expression in tumour samples was assessed using PD-L1 IHC 22C3 pharmDx and quantified using both CPS and tumour proportion score (TPS; PD-L1 expression on tumour cells alone). Calculated immune cell density (CID) was defined as CPS minus TPS. The ability of each scoring method (CPS, TPS, and CID) to predict clinical outcomes with pembrolizumab was evaluated. With pembrolizumab, the area under the receiver operating characteristic curve was 0.69 (95% CI = 0.58-0.80) for CPS, 0.55 (95% CI = 0.46-0.64) for TPS, and 0.67 (95% CI = 0.56-0.77) for CID. After correction for cutoff prevalence, CPS performed as well as, if not better than, CID with respect to predicting objective response rate, progression-free survival, and overall survival. Data from this exploratory analysis suggest that, although PD-L1 expression on immune cells alone is predictive of response to programmed death 1 blockade in mTNBC, adding tumour PD-L1 expression assessment (i.e. CPS, which combines immune cell and tumour cell PD-L1 expression) may improve prediction. PD-L1 CPS thus remains an effective and broadly applicable uniform scoring system for enriching response to programmed death 1 blockade with pembrolizumab in mTNBC as well as other tumour types.

Pembrolizumab plus chemotherapy for first-line treatment of advanced triple-negative breast cancer

Aim: A systematic review and network meta-analysis (NMA) was performed to evaluate the efficacy of first-line treatments for locally recurrent unresectable or metastatic triple-negative breast cancer (TNBC) patients. Materials & methods: Databases were searched for randomized controlled trials evaluating first-line treatments for locally recurrent unresectable or metastatic TNBC patients. NMA was performed to estimate relative treatment effects on overall and progression-free survival between pembrolizumab + chemotherapy and other interventions. Results: NMA including eight trials showed that the relative efficacy of pembrolizumab + chemotherapy was statistically superior to that of other immunotherapy- or chemotherapy-based treatment regimens. Conclusion: Pembrolizumab + chemotherapy confers benefits in survival outcomes versus alternative interventions for the first-line treatment of locally recurrent unresectable or metastatic TNBC patients.

The evolvement of breast cancer therapies: What we have done and where all these head off

Although, from a therapeutic standpoint, breast cancer (BC) is considerably well-characterized, it still leaves puzzling spots. The Her-2+/PR+/ER+ BC can benefit from the mainstays of anticancer therapy and immunotherapy and overall have a better prognosis. Triple-negative BC, due to the concomitant absence of Her-2/PR/ER receptors, is more challenging and necessitates different strategies. It has been learned that the mainstay anti-BC therapies were initially designed to demolish as many cancer cells as they possibly could. However, the number of reports on the adverse effects of these mainstay therapies has recently been increasing. It underpins efforts to reshape such therapies into much better and safer forms over time. Moreover, some current findings on the molecular markers, which are target-potential, have also shifted the paradigm from radical-to-local-yet-precise-approach to meet the need for a therapy platform that is less cytotoxic to normal cells yet efficiently kills cancer cells.

Comparative efficacy of silver alginate dressings versus standard gauze in enhancing wound healing post-mastectomy for triple-negative breast cancer: A systematic review and meta-analysis

This meta-analysis evaluates the efficacy of silver alginate dressings (SAD) compared to standard gauze (SG) in enhancing wound healing and reducing scar formation post-mastectomy in patients with triple-negative breast cancer. From an initial pool of 1245 articles, five studies met the inclusion criteria. The analysis revealed that SAD significantly improve early wound healing 1 week post-mastectomy, as indicated by lower Redness, Edema, Ecchymosis, Discharge, and Approximation (REEDA) scales (I2 = 85%; Random: SMD: -7.08, 95% CI: -8.26 to -5.98, p < 0.01), compared to SG. Additionally, long-term scar outcomes measured by the Manchester Scar Scale (MSS) 5 months post-mastectomy showed a notable reduction in scar formation (I2 = 95%; Random: SMD: -12.97, 95% CI: -16.20 to -9.75, p < 0.01)) in the silver alginate group. The findings support the use of SAD in post-mastectomy care for triple-negative breast cancer patients but highlight the need for further research on long-term safety and cost-effectiveness.

Context-Responsive Nanoparticle Derived from Synthetic Zwitterionic Ionizable Phospholipids in Targeted CRISPR/Cas9 Therapy for Basal-like Breast Cancer

The majority of triple negative breast cancers (TNBCs) are basal-like breast cancers (BLBCs), which tend to be more aggressive, proliferate rapidly, and have poor clinical outcomes. A key prognostic biomarker and regulator of BLBC is the Forkhead box C1 (FOXC1) transcription factor. However, because of its functional placement inside the cell nucleus and its structural similarity with other related proteins, targeting FOXC1 for therapeutic benefit, particularly for BLBC, continues to be difficult. We envision targeted nonviral delivery of CRISPR/Cas9 plasmid toward the efficacious knockdown of FOXC1. Keeping in mind the challenges associated with the use of CRISPR/Cas9 in vivo, including off-targeting modifications, and effective release of the cargo, a nanoparticle with context responsive properties can be designed for efficient targeted delivery of CRISPR/Cas9 plasmid. Consequently, we have designed, synthesized, and characterized a zwitterionic amino phospholipid-derived transfecting nanoparticle for delivery of CRISPR/Cas9. The construct becomes positively charged only at low pH, which encourages membrane instability and makes it easier for nanoparticles to exit endosomes. This has enabled effective in vitro and in vivo downregulation of protein expression and genome editing. Following this, we have used EpCAM aptamer to make the system targeted toward BLBC cell lines and to reduce its off-target toxicity. The in vivo efficacy, biodistribution, preliminary pharmacokinetics, and biosafety of the optimized targeted CRISPR nanoplatform is then validated in a rodent xenograft model. Overall, we have attempted to knockout the proto-oncogenic FOXC1 expression in BLBC cases by efficient delivery of CRISPR effectors via a context-responsive nanoparticle delivery system derived from a designer lipid derivative. We believe that the nonviral approach for in vitro and in vivo delivery of CRISPR/Cas9 targeted toward FOXC1, studied herein, will greatly emphasize the therapeutic regimen for BLBC.

MLL1 regulates cytokine-driven cell migration and metastasis

Cell migration is a critical contributor to metastasis. Cytokine production and its role in cancer cell migration have been traditionally associated with immune cells. We find that the histone methyltransferase Mixed-Lineage Leukemia 1 (MLL1) controls 3D cell migration via cytokines, IL-6, IL-8, and TGF-β1, secreted by the cancer cells themselves. MLL1, with its scaffold protein Menin, controls actin filament assembly via the IL-6/8/pSTAT3/Arp3 axis and myosin contractility via the TGF-β1/Gli2/ROCK1/2/pMLC2 axis, which together regulate dynamic protrusion generation and 3D cell migration. MLL1 also regulates cell proliferation via mitosis-based and cell cycle-related pathways. Mice bearing orthotopic MLL1-depleted tumors exhibit decreased lung metastatic burden and longer survival. MLL1 depletion leads to lower metastatic burden even when controlling for the difference in primary tumor growth rates. Combining MLL1-Menin inhibitor with paclitaxel abrogates tumor growth and metastasis, including preexistent metastasis. These results establish MLL1 as a potent regulator of cell migration and highlight the potential of targeting MLL1 in patients with metastatic disease.

Short peptides based on the conserved regions of MIEN1 protein exhibit anticancer activity by targeting the MIEN1 signaling pathway

Migration and invasion enhancer 1 (MIEN1) overexpression characterizes several cancers and facilitates cancer cell migration and invasion. Leveraging conserved immunoreceptor tyrosine-based activation motif and prenylation motifs within MIEN1, we identified potent anticancer peptides. Among them, bioactive peptides LA3IK and RP-7 induced pronounced transcriptomic and protein expression changes at sub-IC50 concentrations. The peptides effectively inhibited genes and proteins driving cancer cell migration, invasion, and epithelial-mesenchymal transition pathways, concurrently suppressing epidermal growth factor-induced nuclear factor kappa B nuclear translocation in metastatic breast cancer cells. Specifically, peptides targeted the same signal transduction pathway initiated by MIEN1. Molecular docking and CD spectra indicated the formation of MIEN1-peptide complexes. The third-positioned isoleucine in LA3IK and CVIL motif in RP-7 were crucial for inhibiting breast cancer cell migration. This is evident from the limited migration inhibition observed when MDA-MB-231 cells were treated with scrambled peptides LA3IK SCR and RP-7 SCR. Additionally, LA3IK and RP-7 effectively suppressed tumor growth in an orthotopic breast cancer model. Notably, mice tolerated high intraperitoneal (ip) peptide doses of 90 mg/Kg well, surpassing significantly lower doses of 5 mg/Kg intravenously (iv) and 30 mg/Kg intraperitoneally (ip) used in both in vivo pharmacokinetic studies and orthotopic mouse model assays. D-isomers of LA3IK and RP-7 showed enhanced anticancer activity compared to their L-isomers. D-LA3IK remained stable in mouse plasma for 24 h with 75% remaining, exhibiting superior pharmacokinetic properties over D/L-RP-7. In summary, our findings mark the first report of short peptides based on MIEN1 protein sequence capable of inhibiting cancer signaling pathways, effectively impeding cancer progression both in vitro and in vivo.

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.

Role of Epigenetics for the Efficacy of Cisplatin

The clinical utility of the chemotherapeutic agent cisplatin is restricted by cancer drug resistance, which is either intrinsic to the tumor or acquired during therapy. Epigenetics is increasingly recognized as a factor contributing to cisplatin resistance and hence influences drug efficacy and clinical outcomes. In particular, epigenetics regulates gene expression without changing the DNA sequence. Common types of epigenetic modifications linked to chemoresistance are DNA methylation, histone modification, and non-coding RNAs. This review provides an overview of the current findings of various epigenetic modifications related to cisplatin efficacy in cell lines in vitro and in clinical tumor samples. Furthermore, it discusses whether epigenetic alterations might be used as predictors of the platinum agent response in order to prevent avoidable side effects in patients with resistant malignancies. In addition, epigenetic targeting therapies are described as a possible strategy to render cancer cells more susceptible to platinum drugs.

Cost-Effectiveness of Neoadjuvant Pembrolizumab plus Chemotherapy Followed by Adjuvant Pembrolizumab in Patients with High-Risk, Early-Stage, Triple-Negative Breast Cancer in Switzerland

AIM

This study assessed the cost-effectiveness of neoadjuvant pembrolizumab plus chemotherapy followed by adjuvant pembrolizumab versus neoadjuvant chemotherapy plus placebo followed by adjuvant placebo for patients with high-risk, early-stage, triple-negative breast cancer (TNBC) from a Swiss third-party payer perspective over a lifetime horizon (51 years).

MATERIALS AND METHODS

A transition model with four health states (event-free, locoregional recurrence, distant metastasis, and death) was developed to assess the cost-effectiveness of pembrolizumab plus chemotherapy versus chemotherapy alone for the treatment of high-risk, early-stage TNBC. Data were utilized from the KEYNOTE-522 randomized controlled trial (ClinicalTrials.gov, NCT03036488). The incremental cost-effectiveness ratio (ICER) was calculated, which was reported as cost per life year or quality-adjusted life year (QALY) gained. A one-way deterministic sensitivity analysis, a probabilistic sensitivity analysis (PSA) and scenario analyses were conducted to assess the robustness of the model results.

RESULTS

Base-case results estimated an ICER of 14,114 Swiss francs (CHF)/QALY for pembrolizumab plus chemotherapy versus chemotherapy alone. Results were most sensitive to changes in the extrapolation of event-free survival (EFS). All sensitivity and scenario analyses generated ICERs below the willingness-to-pay threshold of CHF100,000/QALY, and the PSA showed a 98.8% probability that the ICER would be below this threshold.

LIMITATIONS

Due to the limited follow-up period in the KEYNOTE-522 trial, EFS data were extrapolated over the lifetime horizon to inform transition probabilities. Extensive validation and scenario analyses ensured the results were robust.

CONCLUSION

The model demonstrated that neoadjuvant pembrolizumab plus chemotherapy followed by adjuvant pembrolizumab was cost-effective versus chemotherapy alone in patients with high-risk, early-stage TNBC in Switzerland.

Novel Strategies Using Sagacious Targeting for Site-Specific Drug Delivery in Breast Cancer Treatment: Clinical Potential and Applications

For more than a decade, researchers have been working to achieve new strategies and smart targeting drug delivery techniques and technologies to treat breast cancer (BC). Nanotechnology presents a hopeful strategy for targeted drug delivery into the building of new therapeutics using the properties of nanomaterials. Nanoparticles are of high regard in the field of diagnosis and the treatment of cancer. The use of these nanoparticles as an encouraging approach in the treatment of various cancers has drawn the interest of researchers in recent years. In order to achieve the maximum therapeutic effectiveness in the treatment of BC, combination therapy has also been adopted, leading to minimal side effects and thus an enhancement in the quality of life for patients. This review article compares, discusses and criticizes the approaches to treat BC using novel design strategies and smart targeting of site-specific drug delivery systems.

Exploring the Regulatory Roles of miR-21, miR-15, and miR-let-7 in ABC Transporter-Mediated Chemoresistance: Implications for Breast Cancer Etiology and Treatment

Breast cancer, a prevalent and aggressive malignancy among females worldwide, poses a significant challenge due to resistance to chemotherapy and tyrosine kinase inhibitors. In breast cancer, ABC transporters play a pivotal role by contributing to chemoresistance and drug efflux, a phenomenon observed also in various cancers. This study aims to elucidate the role of oncomiRs miR-15, miR-21, and miR-let-7 in breast cancer etiology and their impact on chemotherapy-resistant oncogenes ABCA1, ABCB1, and ABCC1. Blood samples from female breast cancer patients were analyzed to assess the expression levels of miRNAs and oncogenes by qPCR. Significantly, miR-21 exhibited a positive correlation with ABCA1 in newly diagnosed patients, while miR-15 and miR-let-7 displayed a positive correlation with ABCA1 in the metastasis group. Additionally, miR-let-7 demonstrated a negative correlation with ABCC1 in newly diagnosed patients. This study's findings provide valuable insights into the cancer etiology of these miRNAs and their interactions with ABCA1, ABCB1, and ABCC1. Targeting these interactions holds promise for mitigating drug efflux and chemoresistance in breast cancer, potentially enhancing current treatments and improving patient outcomes.

Adoption and use of immunotherapy in breast cancer management in Africa: barriers and prospect - a narrative review

Breast cancer (BC) is the world's most frequently diagnosed cancer in women, with 7.8 million women diagnosed with BC in the past 5 years. BC has the highest incidence rate of all cancers in women worldwide (1.67 million), accounting for over 500 000 deaths annually. In Africa, BC accounts for 28% of all cancers and 20% of all cancer deaths in women. The African continent has recorded an alarming increase in incidence, with the highest mortality rate globally. Despite BC being a major health concern in Africa, there is limited access to adequate healthcare services to combat the growing need. Immunotherapy, a promising treatment approach that harnesses the immune system's power to fight cancer, has shown great potential in BC management. However, in the face of the growing body of evidence supporting its effectiveness, the adoption and use of immunotherapy in BC management in Africa remain limited. Hence, this review aimed to explore the barriers and prospects of immunotherapy adoption and use in BC management in Africa. A comprehensive search across various databases and sources using specific keywords related to immunotherapy and BC to achieve the study aim was conducted. The criteria for including data in the study were based on relevance and availability in English, with no publication year restrictions. The collected data underwent narrative analysis, supplemented by information from sources like country reports, newsletters, commentaries, policy briefs, and direct Google searches. By identifying the challenges and opportunities, this review provided insights into how healthcare providers, policymakers, and other stakeholders can work together to improve the availability and accessibility of immunotherapy to BC patients in Africa.

Risk factors and survival of triple-negative breast cancer among breast cancer patients: Ten-year cross-sectional study in the southwestern Iranian population

Background

Breast cancer results from genetic and epigenetic mutations, contributing significantly to cancer-related morbidity and mortality. This study aimed to determine the prevalence and survival rates of triple-negative breast cancer (TNBC) among breast cancer patients in southwestern Iran over a ten-year period.

Methods

This retrospective cross-sectional study aims to assess prognostic factors associated with survival in women diagnosed with breast cancer in Iran's southwestern region over a ten-year period (2007-2017). Data were collected from patients who visited the Clinical Oncology Department at Golestan Hospital in Ahvaz (the breast cancer center of the Southwestern country). The study enrolled women diagnosed with TNBC using a census method and data from medical records. The primary outcome (survival rates) and secondary outcomes (demographic data, diagnostic stages, and three receptors estrogen receptors [ER], progesterone receptor [PR], human epidermal growth factor receptor 2 [HER2] status) were collected.

Results

Breast cancer was diagnosed in 2641 women over ten years; TNBC was diagnosed in 227 individuals (8.59%). Statistical analysis revealed a significant correlation between negative ER status and TNBC (p > 0.05). Furthermore, the prevalence of TNBC differed significantly from that of other types of breast cancer (p = 0.0001). The variables of age, HER2, PR, and TNBC grade did not differ significantly (p > 0.05). The overall disease-free survival rate over 5 years was 88.1%, while the rate for individuals without recurrence was 77.97%.

Conclusion

This study highlights a differentially low incidence of TNBC in the southwestern part of Iran when compared to other regions; genetic or epigenetic influences may explain this discrepancy. ER-negative status is a crucial prognostic indicator in diagnosing TNBC. The incidence of this disease is expected to rise by 100% in 2 years and 77.97% in 5 years.

A review of biological targets and therapeutic approaches in the management of triple-negative breast cancer

BACKGROUND

Triple-negative breast cancer (TNBC) is a heterogeneous, aggressive phenotype of breast cancer with associated chemoresistance. The development of chemo- or radioresistance could be attributed to diverse tumor microenvironments, overexpression of membrane proteins (transporters), epigenetic changes, and alteration of the cell signaling pathways/genes associated with the development of cancer stem cells (CSCs).

AIM OF REVIEW

Due to the diverse and heterogeneous nature of TNBC, therapeutic response to the existing modalities offers limited scope and thus results in reccurance after therapy. To establish landmark therapeutic efficacy, a number of novel therapeutic modalities have been proposed. In addition, reversal of the resistance that developed during treatment may be altered by employing appropriate therapeutic modalities. This review aims to discuss the plethora of investigations carried out, which will help readers understand and make an appropriate choice of therapy directed toward complete elimination of TNBC.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This manuscript addresses the major contributory factors from the tumor microenvironment that are responsible for the development of chemoresistance and poor prognosis. The associated cellular events and molecular mechanism-based therapeutic interventions have been explained in detail. Inhibition of ABC transporters, cell signaling pathways associated with CSCs, and epigenetic modification offers promising results in this regard. TNBC progression, invasion, metastasis and recurrence can also be inhibited by blocking multiple cell signaling pathways, targeting specific receptors/epigenetic targets, disrupting bioenergetics and generating reactive oxygen species (ROS).

Hydroxypropyl-β-cyclodextrin inhibits the development of triple negative breast cancer by enhancing antitumor immunity

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

In vitro anticancer evaluation of Enceleamycin A and its underlying mechanism

It has become more crucial than ever to find novel anticancer compounds due to the rise in cancer mortality and resistance to the present chemotherapeutic drugs. Naphthoquinones are regarded as privileged structures for their ability to inhibit various cancers. The current study examined three novel furo-naphthoquinones (Enceleamycins A-C) previously isolated from Amycolatopsis sp. MCC 0218 for their anticancer potential. Enceleamycin A demonstrated considerable cytotoxicity for triple-negative breast cancer (TNBC) MDA-MB-231 cells with an IC50 value of 1.25 μg mL-1 (3.78 μM). It also showed the ability to inhibit MDA-MB-231 cell migration. Enceleamycin A raises intracellular ROS levels in TNBC cells, ultimately leading to apoptotic cell death, as demonstrated by Annexin V/PI staining. The molecular docking and simulation investigation revealed better binding affinity of Enceleamycin A with AKT2, which plays a vital role in breast cancer's invasiveness and chemo-resistance. Enceleamycin A inhibits the AKT2 enzyme in vitro with an IC50 value of 0.736 μg mL-1 (2.22 μM), further validating the docking study. The in silico physicochemical and pharmacokinetics characteristics of Enceleamycin A demonstrated its drug-likeness. Intriguingly, Enceleamycin A is non-hemolytic in nature. Taken together, Enceleamycin A could be a candidate molecule for treating TNBC cells by targeting the AKT2 signaling pathway.

Locally Advanced Adenoid Cystic Carcinoma of the Breast-A Case Report with a Review of the Literature

Breast cancer (BC) is a heterogeneous disease distinguished by four main subtypes based on the expression of estrogen, progesterone receptors, and human epidermal growth factor-2 on the cancer cells. Triple-negative breast cancer (TNBC) consists of approximately 10-20% of all BCs and is characterized by a poor prognosis. Adenoid cystic carcinoma (ACC) of the breast is a rare, special type of TNBC with low metastatic potential and usually favorable prognosis. There are no established recommendations concerning systemic therapy in advanced ACC. We present a case of a 70-year-old woman with locally advanced ACC with progression after radical mastectomy, and review the literature concerning the treatment of metastatic disease focused on systemic therapy.

Anti-cancer effect of a phytochemical compound - 7R-acetylmelodorinol - against triple-negative breast cancer cells

Triple-negative breast cancer (TNBC) is a highly aggressive subtype currently lacking effective treatment options. Consequently, novel and effective drugs or compounds are urgently needed to treat TNBC. Therefore, this study aimed to evaluate the potential of 7R-acetylmelodorinol (7R-AMDL), a phytochemical compound isolated from Xylopia pierrei Hance, a plant found in Thailand, as a novel therapeutic agent for TNBC. MTT and clonogenic assays showed that 7R-AMDL significantly reduced the survival of breast cancer cell lines, with a markedly potent effect on MDA-MB-231 cells. Flow cytometry showed that treating MDA-MB-231 cells with 7R-AMDL at the concentration of dose 8 µM significantly increased early and late apoptosis after 24 and 48 h compared to the control group (p < 0.0001). The highest tested 7R-AMDL dose upregulated the death receptors and their ligands, with extrinsic and intrinsic apoptosis pathways significantly activated via the caspase cascade, compared to the untreated group (p < 0.05). In addition, immunoblots showed decreased BCL2-like 1 (BCL2L1/Bcl-xL) expression (p < 0.0001). Furthermore, wound healing and Transwell assays showed that at a non-cytotoxic dose (≤4 µM), 7R-AMDL significantly inhibited the MDA-MB-231 cell migration and invasion. This reduction in cell migration was associated with decreased matrix metallopeptidase 9 (MMP-9) expression (p < 0.01) and nuclear factor kappa B (NF-κB) activation (p < 0.05). Altogether, 7R-AMDL has anti-cancer effects against TNBC and the potential to be further developed and evaluated for treating this disease.

Identification of TUBB2A as a Cancer-Immunity Cycle-Related Therapeutic Target in Triple-Negative Breast Cancer

OBJECTIVE

Triple negative breast cancer (TNBC) is a malignant subtype of breast cancer characterized by the absence of ER, PR, and HER2. We aimed to explore target gene from the perspective of cancer-immunity cycle, providing insights into treatment of TNBC.

METHODS

We obtained TNBC samples from METABRIC database and downloaded 4 datasets from GEO database, as well as an IMvigor210 dataset. WGCNA was applied to screen genes associated with cancer-immunity cycle in TNBC. GO, KEGG and GSEA analyses were performed to explore the target gene's potential functions and pathways. The binding motifs with transcription factors were predicted with FIMO. Immune infiltration analysis was conducted by CIBERSORT.

RESULTS

TUBB2A was screened out as our target gene which was negatively correlated with T cell recruitment in cancer-immunity cycle. TUBB2A expressed higher in TNBC samples than in normal samples. High expression of TUBB2A was associated with poor prognosis of TNBC. 12 transcription factors and 5 miRNAs might regulate TUBB2A's expression. The infiltration ratios of 7 types of immune cells such as CD8+ T cells, naive CD4+ T cells and activated memory CD4+ T cells were significantly lower in TUBB2A high expression group. TUBB2A was a potential drug target.

CONCLUSION

We screened a cancer-immunity cycle-related gene TUBB2A which was negatively correlated with T cell recruiting in TNBC. TUBB2A expressed higher in TNBC samples than in normal samples, associated with poor prognosis.

Synthesis, anticancer activity and molecular modeling study of novel substituted triazole linked tetrafluoronaphthalene hybrid derivatives

To create some novel anticancer molecules, a library of novel series of various triazoles linked to the hydroxyl group of 5,6,7,8-tetrafluoronaphthalen-1-ol (3) was designed and synthesized via CuAAC reaction 'Click Chemistry' of tetrafluoronaphthalene based terminal alkyne with substituted organic azides. The structural characterizations of the targeted Click products 9-18 were confirmed by FTIR, 1H NMR, 19F NMR, 13C NMR and HRMS spectroscopy. Synthesized compounds were tested in two triple negative breast cancer (TNBC) cell lines to understand their anticancer potentials. According to our findings, compounds 14 and 13 showed high cytotoxicity in BT549 cells at 20 μM and 30 μM, respectively. Moreover, these compounds blocked the migration of BT549 cells. In the MDA-MB-231 cell line, compound 18 exhibited high cytotoxicity and can block cell migration for 24 h. Molecular docking study with synthesized novel compounds was performed by Glide/SP method against SphK1 drug target. Furthermore, molecular dynamics (MD) simulation was carried out for the compounds 12-14 and 18. The compounds 13 and 14 may be potential inhibitor candidates in place of a reference inhibitor. A pharmacophore model was generated with the most potent compound 14, and the approved drugs were screened using the modules of Discovery Studio to find similar drugs. Consequently, this comprehensive study encompassing design, synthesis, in vitro and in silico analyses were correlated with the structure-activity relationship between compounds. The findings have the potential to unveil promising drug candidates for future studies.Communicated by Ramaswamy H. Sarma.

Upregulation of Matrix Metalloproteinases in the Metastatic Cascade of Breast Cancer to the Brain

BACKGROUND

In patients with triple-negative breast cancer (TNBC), brain metastasis is a fatal consequence. Matrix metalloproteinases (MMPs), especially MMP-2 and MMP-9 as the major members of the MMP family, are involved in many different facets of breast cancer metastasis.

AIMS

In this study, we sought the MMPs expression in the metastatic cascade of TNBC.

METHODS AND RESULTS

Primary breast cancer cells known as 4T1T were extracted from the tumor mass following the creation of an animal model of TNBC. The brain metastasis lesions of malignant mice were used to extract highly brain metastatic tumor cells known as 4T1B. Gelatinase zymography and real-time polymerase chain reaction (RT-PCR) were used to examine the expression of MMPs at the proteomic and transcriptomic levels in 4T1T and 4T1B. Our results indicated; brain metastatic tumor cells greatly increased their expression of MMPs. In 4T1B, MMP-2 and MMP-9 gene expression were upregulated by 4 and 3.4 folds respectively. Zymographic analysis found MMP activity only in 4T1B.

CONCLUSION

These results offer significant information about the massive alteration of MMPs expression in the brain metastasis of TNBC. By analyzing the molecular characteristics of brain metastatic tumor cells, we can understand the molecular and genetic features of brain metastasis and develop tailored therapeutic strategies to combat TNBC brain metastasis.

Targeting NKG2DL with Bispecific NKG2D-CD16 and NKG2D-CD3 Fusion Proteins on Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a particularly aggressive subtype of breast cancer with a poor response rate to conventional systemic treatment and high relapse rates. Members of the natural killer group 2D ligand (NKG2DL) family are expressed on cancer cells but are typically absent from healthy tissues; thus, they are promising tumor antigens for novel immunotherapeutic approaches. We developed bispecific fusion proteins (BFPs) consisting of the NKG2D receptor domain targeting multiple NKG2DLs, fused to either anti-CD3 (NKG2D-CD3) or anti-CD16 (NKG2D-CD16) Fab fragments. First, we characterized the expression of the NKG2DLs (MICA, MICB, ULBP1-4) on TNBC cell lines and observed the highest surface expression for MICA and ULBP2. Targeting TNBC cells with NKG2D-CD3/CD16 efficiently activated both NK and T cells, leading to their degranulation and cytokine release and lysis of TNBC cells. Furthermore, PBMCs from TNBC patients currently undergoing chemotherapy showed significantly higher NK and T cell activation and tumor cell lysis when stimulated with NKG2D-CD3/CD16. In conclusions, BFPs activate and direct the NK and T cells of healthy and TNBC patients against TNBC cells, leading to efficient eradication of tumor cells. Therefore, NKG2D-based NK and T cell engagers could be a valuable addition to the treatment options for TNBC patients.

Neoadjuvant immunotherapy and chemotherapy regimens for the treatment of high-risk, early-stage triple-negative breast cancer: a systematic review and network meta-analysis

BACKGROUND

Patients with triple-negative breast cancer (TNBC) are generally younger and more likely to experience disease recurrence and have the shortest survival among all breast cancer patients. Recently, neoadjuvant delivery of the programmed cell death protein-1 inhibitor pembrolizumab plus chemotherapy followed by adjuvant pembrolizumab was approved for patients with high-risk, early-stage TNBC, but this treatment regimen has not been evaluated in head-to-head trials with other neoadjuvant treatment regimens. Therefore, the objective of this study was to estimate the relative efficacy of neoadjuvant pembrolizumab + chemotherapy followed by adjuvant pembrolizumab versus other neoadjuvant treatments for early-stage TNBC through a systematic review and network meta-analysis (NMA).

METHODS

EMBASE, MEDLINE, Cochrane Central Register of Controlled Trials, conference abstracts, and clinical trial registries were searched for randomized controlled trials evaluating neoadjuvant treatments for early-stage TNBC. NMA was performed to estimate relative treatment effects among evaluated interventions.

RESULTS

Five trials met the inclusion criteria and were included in the NMA. The relative efficacy of neoadjuvant pembrolizumab + chemotherapy followed by adjuvant pembrolizumab was favorable to paclitaxel followed by anthracycline + cyclophosphamide in terms of pathologic complete response (pCR), event-free survival (EFS), and overall survival; paclitaxel + carboplatin followed by anthracycline + cyclophosphamide in terms of pCR and EFS; paclitaxel + bevacizumab followed by anthracycline + cyclophosphamide + bevacizumab in terms of pCR; and paclitaxel + carboplatin + veliparib followed by anthracycline + cyclophosphamide in terms of EFS.

CONCLUSIONS

Neoadjuvant pembrolizumab + chemotherapy followed by adjuvant pembrolizumab confers benefits in response and survival outcomes versus alternative neoadjuvant treatments for early-stage TNBC.

Machine Learning-driven Fragment-based Discovery of CIB1-directed Anti-Tumor Agents by FRASE-bot

Chemical probes are an indispensable tool for translating biological discoveries into new therapies, though are increasingly difficult to identify. Novel therapeutic targets are often hard-to-drug proteins, such as messengers or transcription factors. Computational strategies arise as a promising solution to expedite drug discovery for unconventional therapeutic targets. FRASE-bot exploits big data and machine learning (ML) to distill 3D information relevant to the target protein from thousands of protein-ligand complexes to seed it with ligand fragments. The seeded fragments can then inform either (i) de novo design of 3D ligand structures or (ii) ultra-large-scale virtual screening of commercially available compounds. Here, FRASE-bot was applied to identify ligands for Calcium and Integrin Binding protein 1 (CIB1), a promising but ligand-orphan drug target implicated in triple negative breast cancer. The signaling function of CIB1 relies on protein-protein interactions and its structure does not feature any natural ligand-binding pocket. FRASE-based virtual screening identified the first small-molecule CIB1 ligand (with binding confirmed in a TR-FRET assay) showing specific cell-killing activity in CIB1-dependent cancer cells, but not in CIB1-depleted cells.

Small EV in plasma of triple negative breast cancer patients induce intrinsic apoptosis in activated T cells

Small extracellular vesicles (sEV) in TNBC patients' plasma promote T cell dysfunction and tumor progression. Here we show that tumor cell-derived exosomes (TEX) carrying surface PDL-1, PD-1, Fas, FasL, TRAIL, CTLA-4 and TGF-β1 induce apoptosis of CD8+T and CD4+T cells but spare B and NK cells. Inhibitors blocking TEX-induce receptor/ligand signals and TEX pretreatments with proteinase K or heat fail to prevent T cell apoptosis. Cytochalasin D, Dynosore or Pit Stop 2, partly inhibit TEX uptake but do not prevent T cell apoptosis. TEX entry into T cells induces cytochrome C and Smac release from mitochondria and caspase-3 and PARP cleavage in the cytosol. Expression of survival proteins is reduced in T cells undergoing apoptosis. Independently of external death receptor signaling, TEX entry into T cells induces mitochondrial stress, initiating relentless intrinsic apoptosis, which is responsible for death of activated T cells in the tumor-bearing hosts. The abundance of TEX in cancer plasma represents a danger for adoptively transferred T cells, limiting their therapeutic potential.

Prox1 Suppresses the Proliferation of Breast Cancer Cells via Direct Inhibition of c-Myc Gene Expression

Breast cancer is one of the most lethal malignancies in women worldwide and is characterized by rapid growth and low survival rates, despite advances in tumor biology and therapies. Novel therapeutic approaches require new insights into the molecular mechanisms of malignant transformation and progression. To this end, here, we identified Prox1 as a negative regulator of proliferation and tumor-related metabolism in breast cancer. In particular, we showed that breast tumors from human patients exhibited reduced levels of Prox1 expression, while high expression levels of Prox1 were associated with a favorable prognosis in breast cancer patients. Moreover, we experimentally demonstrated that Prox1 was sufficient to strongly suppress proliferation, migration, and the Warburg effect in human breast cancer cells without inducing apoptosis. Most importantly, over-expression of Prox1 inhibited breast tumor growth in vivo in both heterotopic and orthotopic xenograft mouse models. The anti-tumorigenic effect of Prox1 was mediated by the direct repression of c-Myc transcription and its downstream target genes. Consistently, c-Myc over-expression from an artificial promoter that was not targeted by Prox1 reversed Prox1's anti-tumor effects. These findings suggest that Prox1 has a tumor suppressive role via direct transcriptional regulation of c-Myc, making it a promising therapeutic gene for breast cancer.

Hypoxia: syndicating triple negative breast cancer against various therapeutic regimens

Triple-negative breast cancer (TNBC) is one of the deadliest subtypes of breast cancer (BC) for its high aggressiveness, heterogeneity, and hypoxic nature. Based on biological and clinical observations the TNBC related mortality is very high worldwide. Emerging studies have clearly demonstrated that hypoxia regulates the critical metabolic, developmental, and survival pathways in TNBC, which include glycolysis and angiogenesis. Alterations to these pathways accelerate the cancer stem cells (CSCs) enrichment and immune escape, which further lead to tumor invasion, migration, and metastasis. Beside this, hypoxia also manipulates the epigenetic plasticity and DNA damage response (DDR) to syndicate TNBC survival and its progression. Hypoxia fundamentally creates the low oxygen condition responsible for the alteration in Hypoxia-Inducible Factor-1alpha (HIF-1α) signaling within the tumor microenvironment, allowing tumors to survive and making them resistant to various therapies. Therefore, there is an urgent need for society to establish target-based therapies that overcome the resistance and limitations of the current treatment plan for TNBC. In this review article, we have thoroughly discussed the plausible significance of HIF-1α as a target in various therapeutic regimens such as chemotherapy, radiotherapy, immunotherapy, anti-angiogenic therapy, adjuvant therapy photodynamic therapy, adoptive cell therapy, combination therapies, antibody drug conjugates and cancer vaccines. Further, we also reviewed here the intrinsic mechanism and existing issues in targeting HIF-1α while improvising the current therapeutic strategies. This review highlights and discusses the future perspectives and the major alternatives to overcome TNBC resistance by targeting hypoxia-induced signaling.

Breast cancer brain metastasis: from etiology to state-of-the-art modeling

Currently, breast carcinoma is the most common form of malignancy and the main cause of cancer mortality in women worldwide. The metastasis of cancer cells from the primary tumor site to other organs in the body, notably the lungs, bones, brain, and liver, is what causes breast cancer to ultimately be fatal. Brain metastases occur in as many as 30% of patients with advanced breast cancer, and the 1-year survival rate of these patients is around 20%. Many researchers have focused on brain metastasis, but due to its complexities, many aspects of this process are still relatively unclear. To develop and test novel therapies for this fatal condition, pre-clinical models are required that can mimic the biological processes involved in breast cancer brain metastasis (BCBM). The application of many breakthroughs in the area of tissue engineering has resulted in the development of scaffold or matrix-based culture methods that more accurately imitate the original extracellular matrix (ECM) of metastatic tumors. Furthermore, specific cell lines are now being used to create three-dimensional (3D) cultures that can be used to model metastasis. These 3D cultures satisfy the requirement for in vitro methodologies that allow for a more accurate investigation of the molecular pathways as well as a more in-depth examination of the effects of the medication being tested. In this review, we talk about the latest advances in modeling BCBM using cell lines, animals, and tissue engineering methods.

Maternal Embryonic Leucine Zipper Kinase is Associated with Metastasis in Triple-negative Breast Cancer

Triple-negative breast cancer (TNBC) has high relapse and metastasis rates and a high proportion of cancer stem-like cells (CSC), which possess self-renewal and tumor initiation capacity. MELK (maternal embryonic leucine zipper kinase), a protein kinase of the Snf1/AMPK kinase family, is known to promote CSC maintenance and malignant transformation. However, the role of MELK in TNBC metastasis is unknown; we sought to address this in the current study. We found that MELK mRNA levels were higher in TNBC tumors [8.11 (3.79-10.95)] than in HR+HER2- tumors [6.54 (2.90-9.26)]; P < 0.001]. In univariate analysis, patients with breast cancer with high-MELK-expressing tumors had worse overall survival (P < 0.001) and distant metastasis-free survival (P < 0.01) than patients with low-MELK-expressing tumors. In a multicovariate Cox regression model, high MELK expression was associated with shorter overall survival after adjusting for other baseline risk factors. MELK knockdown using siRNA or MELK inhibition using the MELK inhibitor MELK-In-17 significantly reduced invasiveness, reversed epithelial-to-mesenchymal transition, and reduced CSC self-renewal and maintenance in TNBC cells. Nude mice injected with CRISPR MELK-knockout MDA-MB-231 cells exhibited suppression of lung metastasis and improved overall survival compared with mice injected with control cells (P < 0.05). Furthermore, MELK-In-17 suppressed 4T1 tumor growth in syngeneic BALB/c mice (P < 0.001). Our findings indicate that MELK supports metastasis by promoting epithelial-to-mesenchymal transition and the CSC phenotype in TNBC.

Significance

These findings indicate that MELK is a driver of aggressiveness and metastasis in TNBC.

Integration of multiomics data shows down regulation of mismatch repair and tubulin pathways in triple-negative chemotherapy-resistant breast tumors

BACKGROUND

Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype. Patients with TNBC are primarily treated with neoadjuvant chemotherapy (NAC). The response to NAC is prognostic, with reductions in overall survival and disease-free survival rates in those patients who do not achieve a pathological complete response (pCR). Based on this premise, we hypothesized that paired analysis of primary and residual TNBC tumors following NAC could identify unique biomarkers associated with post-NAC recurrence.

METHODS AND RESULTS

We investigated 24 samples from 12 non-LAR TNBC patients with paired pre- and post-NAC data, including four patients with recurrence shortly after surgery (< 24 months) and eight who remained recurrence-free (> 48 months). These tumors were collected from a prospective NAC breast cancer study (BEAUTY) conducted at the Mayo Clinic. Differential expression analysis of pre-NAC biopsies showed minimal gene expression differences between early recurrent and nonrecurrent TNBC tumors; however, post-NAC samples demonstrated significant alterations in expression patterns in response to intervention. Topological-level differences associated with early recurrence were implicated in 251 gene sets, and an independent assessment of microarray gene expression data from the 9 paired non-LAR samples available in the NAC I-SPY1 trial confirmed 56 gene sets. Within these 56 gene sets, 113 genes were observed to be differentially expressed in the I-SPY1 and BEAUTY post-NAC studies. An independent (n = 392) breast cancer dataset with relapse-free survival (RFS) data was used to refine our gene list to a 17-gene signature. A threefold cross-validation analysis of the gene signature with the combined BEAUTY and I-SPY1 data yielded an average AUC of 0.88 for six machine-learning models. Due to the limited number of studies with pre- and post-NAC TNBC tumor data, further validation of the signature is needed.

CONCLUSION

Analysis of multiomics data from post-NAC TNBC chemoresistant tumors showed down regulation of mismatch repair and tubulin pathways. Additionally, we identified a 17-gene signature in TNBC associated with post-NAC recurrence enriched with down-regulated immune genes.

Characterization of clinicopathological features, treatment practices, and outcomes among Finnish advanced breast cancer patients in real-life clinical practice

PURPOSE

In recent years, several new targeted therapies have emerged for advanced breast cancer (aBC). However, real-life data specific to aBC and different breast cancer subtypes are scarce. This retrospective cohort study was designed to describe the distribution of aBC subtypes, incidence, treatment patterns, survival, and PIK3CA hotspot mutation frequency.

METHODS

The study included all patients in the Hospital District of Southwest Finland diagnosed with aBC between 2004 and 2013 and with a sample available in Auria Biobank. In addition to registry-based data collection, 161 HR+/HER2- aBCs were screened for PIK3CA mutations.

RESULTS

Altogether, 54.7% of the 444 patients included in the study had luminal B subtype. The smallest representations were in HR-/HER2+ (4.5%) and triple-negative (5.6%) subgroups. The percentage of aBC among all diagnosed breast cancers increased until 2010, after which it remained stable. The triple-negative cancers were associated with shorter median overall survival (5.5 months) compared to other subgroups (16.5-24.6 months). Most (84%) triple-negative cancers also metastasized during the first two years, whereas this was more evenly distributed over time in other subgroups. Of the HR+/HER2- tumors, 32.3% harbored a PIK3CA hotspot mutation. These patients, however, did not have inferior survival compared to patients with PIK3CA wild-type cancers.

CONCLUSION

This study described real-world aBC subgroups and indicated that the clinical outcomes of subgroups vary. Although PIK3CA hotspot mutations did not lead to inferior survival, they are relevant as possible treatment targets. Overall, these data could be utilized to further evaluate the subgroup-specific medical needs in breast cancer.

Comparative efficacy and safety of PD-1/PD-L1 inhibitors in triple negative breast cancer: a systematic review and network meta-analysis of randomized controlled trials

BACKGROUND

Triple-Negative Breast Cancer (TNBC) is a lethal subtype of breast cancer with limited treatment options. The purpose of this Network Meta-Analysis (NMA) is to compare the efficacy and safety of inhibitors of programmed cell death 1 (PD-1) and programmed cell death ligand 1 (PD-L1) in treating TNBC.

METHODS

Our search strategy was used in six databases: PubMed, Cochrane Library, Cumulative Index to Nursing and Allied Health Literature database, Embase, Scopus, and Web of Science up to November 2nd, 2022, as well as a thorough search in the most used trial registries. We included phase II and III randomized controlled trials that looked at the efficacy of PD-1/PD-L1 inhibitors in the treatment of TNBC and reported either Overall Survival (OS), Progression-Free Survival (PFS), or pathological Complete Response (pCR). The risk of bias was assessed utilizing Cochrane's risk of bias 2 tool, and the statistical analysis was performed using a frequentist contrast-based method for NMA by employing standard pairwise meta-analysis applying random effects model.

RESULTS

12 trials (5324 patients) were included in our NMA including seven phase III trials. Pembrolizumab in a neoadjuvant setting achieved a pooled OS of 0.82 (95% Confidence Interval (CI) 0.65 to 1.03), a PFS of 0.82 (95% CI 0.71 to 0.94) and a pCR 2.79 (95% CI 1.07 to 7.24) compared to Atezolizumab's OS of 0.92 (95% CI 0.74 to 1.15), PFS of 0.82 (95% CI 0.69 to 0.97), and pCR of 1.94 (95% CI 0.86 to 4.37). Atezolizumab had less grade ≥ 3 adverse events (OR 1.48, 95% CI 0.90 to 2.42) than Pembrolizumab (OR 1.90, 95% CI 1.08 to 3.33) in the neoadjuvant setting.

CONCLUSIONS

PD-1/PD-L1 inhibitors exhibited varying efficacy in terms of OS, PFS, and pCR. They were associated with an increase in immune-related adverse effects. When used early in the course of TNBC, PD-1/PD-L1 inhibitors exert their maximum benefit. Durvalumab as a maintenance treatment instead of chemotherapy has shown promising outcomes. Future studies should focus on PD-L1 expression status and TNBC subtypes, since these factors may contribute to the design of individualized TNBC therapy regimens. Systematic review registration PROSPERO Identifier: CRD42022380712.

Structure-based virtual screening for identification of potential CDC20 inhibitors and their therapeutic evaluation in breast cancer

Cell division cycle 20 (CDC20), a critical partner of anaphase promoting complex (APC/C), is indispensably required for metaphase-to-anaphase transition. CDC20 overexpression in TNBC breast cancer patients has been found to be correlated with poor prognosis, hence, we aimed to target CDC20 for TNBC therapeutics. In silico molecular docking of large-scale chemical libraries (phytochemicals/synthetic drugs) against CDC20 protein structure identified five synthetic drugs and four phytochemicals as potential hits interacting with CDC20 active site. The molecular selection was done based on docking scores, binding interactions, binding energies and MM/GBSA scores. Further, we analysed ADME profiles for all the hits and identified lidocaine, an aminoamide anaesthetic group of synthetic drug, with high drug-likeness properties. We explored the anti-tumorigenic effects of lidocaine on MDA-MB-231 TNBC breast cancer cells, which resulted in increased growth inhibition in dose-dependent manner. The molecular mechanism behind the cell viability defect mediated by lidocaine was found to be induction of G2/M cell cycle arrest and cellular apoptosis. Notably, lidocaine treatment of TNBC cells also resulted in downregulation of CDC20 gene expression. Thus, this study identifies lidocaine as a potential anti-neoplastic agent for TNBC cells emphasizing CDC20 as a suitable therapeutic target for breast cancer.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03554-7.

Regulation of ERα-dependent breast cancer metastasis by a miR-29a signaling

Malignant breast cancer (BC) remains incurable mainly due to the cancer cell metastasis, which is mostly related to the status of Estrogen receptor alpha (ERα). However, our understanding of the mechanisms through which ERα regulates cancer cell metastasis remains limited. Here we identified a miR-29a-PTEN-AKT axis as a downstream signaling pathway of ERα governing breast cancer progression and metastasis. Two estrogen response element (ERE) half sites were identified in the promoter and enhancer regions of miR-29a, which mediated transcriptional regulation of miR-29a by ERα. Low level of miR-29a showed association with reduced metastasis and better survival in ERα+ luminal subtype of BC. In contrast, high level of miR-29a was detected in ERα- triple negative breast cancer (TNBC) in association with distant metastasis and poor survival. miR-29a overexpression in BC tumors increased the number of circulating tumor cells and promoted lung metastasis in mice. Targeted knockdown of miR-29a in TNBC cells in vitro or administration of a nanotechnology-based anti-miR-29a delivery in TNBC tumor-bearing mice in vivo suppressed cellular invasion, EMT and lung metastasis. PTEN was identified as a direct target of miR-29a, inducing EMT and metastasis via AKT signaling. A small molecular inhibitor of AKT attenuated miR-29a-induced EMT. These findings demonstrate a novel mechanism responsible for ERα-regulated breast cancer metastasis, and reveal the combination of ERα status and miR-29a levels as a new risk indicator in BC.

S1P1 Threonine 236 Phosphorylation Mediates the Invasiveness of Triple-Negative Breast Cancer and Sensitivity to FTY720

Hyperactive sphingosine 1-phosphate (S1P) signaling is associated with a poor prognosis of triple-negative breast cancer (TNBC). Despite recent evidence that links the S1P receptor 1 (S1P1) to TNBC cell survival, its role in TNBC invasion and the underlying mechanisms remain elusive. Combining analyses of human TNBC cells with zebrafish xenografts, we found that phosphorylation of S1P receptor 1 (S1P1) at threonine 236 (T236) is critical for TNBC dissemination. Compared to luminal breast cancer cells, TNBC cells exhibit a significant increase of phospho-S1P1 T236 but not the total S1P1 levels. Misexpression of phosphorylation-defective S1P1 T236A (alanine) decreases TNBC cell migration in vitro and disease invasion in zebrafish xenografts. Pharmacologic disruption of S1P1 T236 phosphorylation, using either a pan-AKT inhibitor (MK2206) or an S1P1 functional antagonist (FTY720, an FDA-approved drug for treating multiple sclerosis), suppresses TNBC cell migration in vitro and tumor invasion in vivo. Finally, we show that human TNBC cells with AKT activation and elevated phospho-S1P1 T236 are sensitive to FTY720-induced cytotoxic effects. These findings indicate that the AKT-enhanced phosphorylation of S1P1 T236 mediates much of the TNBC invasiveness, providing a potential biomarker to select TNBC patients for the clinical application of FTY720.

Proteomic profiling and ROC analysis identify CD151 and ELAVL1 as potential therapy response markers for the antiviral drug in resistant TNBC

Triple-negative breast cancer is high heterogeneous, aggressive, and metastatic with poor prognosis. Despite of advances in targeted therapies, TNBC has been reported to cause high morbidity and mortality. A rare subpopulation within the tumor microenvironment organized into a hierarchy of cancer stem cells is responsible for therapy resistance and tumor recurrence. Repurposing of antiviral drugs for cancer treatment is gaining momentum due to reduced cost, labour, and research time, but limited due to lack of prognostic, and predictive markers. The present study investigates proteomic profiling and ROC analysis to identify CD151 and ELAVL1 as potential therapy response markers for the antiviral drug 2-thio-6-azauridine (TAU) in resistant TNBC. The stemness of MDA-MB 231 and MDA-MD 468 adherent cells was enriched by culturing them under non-adherent and non-differentiation conditions. Then, CD151⁺ subpopulation was isolated and characterized for the enrichment of stemness. This study found that CD151 has overexpressed in stemness enriched subpopulations, and also showed CD44 high and CD24 low expression along with stem cell-related transcription factors octamer-binding transcription factor 4 (OCT4) and Sex determining Y-box 2 (SOX2). This study also found that TAU induced significant cytotoxicity and genotoxicity in the CD151⁺TNBC subpopulation and inhibited their proliferation by inducing DNA damage, cell cycle arrest at the G₂M phase, and apoptosis. Further, a proteomic profiling study showed that the expression of CD151 along with ELAVL1, an RNA-binding protein, was significantly reduced with TAU treatment. KM plotter showed correlation of CD151 and ELAVL1 gene expression with a poor prognosis of TNBC. ROC analysis predicted and validated CD151 and ELAVL1 as best therapy response marker for TAU in TNBC. These findings provide new insight into repurposing antiviral drug TAU for treatment of metastatic and drug resistant TNBC.

Therapeutic significance of molecular hybrids for breast cancer research and treatment

Worldwide, breast cancer is still a leading cause of cancer death in women. Indeed, over the years, several anti-breast cancer drugs have been developed; however, the complex heterogeneous nature of breast cancer disease reduces the applicability of conventional targeted therapies with the upsurge in side effects and multi-drug resistance. Molecular hybrids generated by a combination of two or more active pharmacophores emerged as a promising approach in recent years for the design and synthesis of anti-breast cancer drugs. The hybrid anti-breast cancer molecules are well known for their several advantages compared to the parent moiety. These hybrid forms of anti-breast cancer molecules demonstrated remarkable effects in blocking different pathways contributing to the pathogenies of breast cancer and improved specificity. In addition, these hybrids are patient compliant with reduced side effects and multi-drug resistance. The literature revealed that molecular hybrids are applied to discover and develop novel hybrids for various complex diseases. This review article highlights the recent progress (∼2018-2022) in developing molecular hybrids, including linked, merged, and fused hybrids, as promising anti-breast cancer agents. Furthermore, their design principles, biological potential, and future perspective are discussed. The provided information will lead to the development of novel anti-breast cancer hybrids with excellent pharmacological profiles in the future.

Benzoxazole-appended piperidine derivatives as novel anticancer candidates against breast cancer

Novel series of benzoxazole-appended piperidine derivatives were planned, synthesized and screened against two breast cancer cell lines. Considerable antiproliferative activity was observed for screened compounds (IC₅₀ = 33.32 ± 0.2 µM to 7.31 ± 0.43 µM and 1.66 ± 0.08 µM to 12.10 ± 0.57 µM) against MCF-7 and MDA-MB-231 cell lines respectively being more potent than doxorubicin (IC₅₀ = 8.20 ± 0.39 µM and 13.34 ± 0.63 µM respectively). Active compounds were submitted for enzyme inhibition assays when 4d and 7h demonstrated potent EGFR inhibition (0.08 ± 0.002 µM and 0.09 ± 0.002 µM respectively) compared to erlotinib (0.11 ± 0.003 µM). However, no one compound displayed effective ARO inhibition activity as tested compounds were less active than letrozole. Apoptosis inducing ability results implied that apoptosis was provoked by significant stimulation of caspase-9 protein levels (4.25-7.04-fold) upon treatment of MCF-7 cells with 4a, 7h, 9, 12e and 12f. Alternatively, MDA-MB-231 cells treated with 4d, 7a, 12b and 12c considerably increased caspase-9 levels (2.32-4.06-fold). Cell cycle arrest and annexin-V/Propidium iodide assays further confirmed apoptosis when tested compounds arrested cell cycle at various phases and demonstrated high annexin V binding affinity. Docking outcomes proved valuable binding affinities for compounds 4d and 7h to EGFR enzyme while compounds 4a and 12e, upon docking into the active site of ARO, failed to interact with heme, suggesting their inabilities to act as AIs. Therefore, these benzoxazoles can act as promising candidates exhibiting EGFR inhibition and apoptosis-promoting properties.

Critical Review on the Different Roles of Exosomes in TNBC and Exosomal-Mediated Delivery of microRNA/siRNA/lncRNA and Drug Targeting Signalling Pathways in Triple-Negative Breast Cancer

Triple-negative breast cancer is the most potent metastatic type of breast cancer that can spread to other body parts. Chemotherapy and surgical intervention are the sole treatments for TNBC, owing to the scarcity of therapeutic targets. Manipulation of the membranes as per the desired targets of exosomes has recently gained much attention as a drug delivery method. Despite their known roles in different diseases, very few studies have focused on signalling that triggers the metastasis of triple-negative breast cancer to other body parts by exosomes. This article highlights the significant roles of exosomes associated with TNBC, the involvement of exosomes in breast cancer diagnosis, progression, and the treatment of triple-negative breast cancer by the exosomes as a drug delivery system. This review paper also illustrates the role of exosomes in initiating EMT in breast cancer, including novel signalling.

Radiosensitization of Breast Cancer Cells with a 2-Methoxyestradiol Analogue Affects DNA Damage and Repair Signaling In Vitro

Radiation resistance and radiation-related side effects warrant research into alternative strategies in the application of this modality to cancer treatment. Designed in silico to improve the pharmacokinetics and anti-cancer properties of 2-methoxyestradiol, 2-ethyl-3-O-sulfamoyl-estra-1,3,5(10)16-tetraene (ESE-16) disrupts microtubule dynamics and induces apoptosis. Here, we investigated whether pre-exposure of breast cancer cells to low-dose ESE-16 would affect radiation-induced deoxyribonucleic acid (DNA) damage and the consequent repair pathways. MCF-7, MDA-MB-231, and BT-20 cells were exposed to sub-lethal doses of ESE-16 for 24 h before 8 Gy radiation. Flow cytometric quantification of Annexin V, clonogenic studies, micronuclei quantification, assessment of histone H2AX phosphorylation and Ku70 expression were performed to assess cell viability, DNA damage, and repair pathways, in both directly irradiated cells and cells treated with conditioned medium. A small increase in apoptosis was observed as an early consequence, with significant repercussions on long-term cell survival. Overall, a greater degree of DNA damage was detected. Moreover, initiation of the DNA-damage repair response was delayed, with a subsequent sustained elevation. Radiation-induced bystander effects induced similar pathways and were initiated via intercellular signaling. These results justify further investigation of ESE-16 as a radiation-sensitizing agent since pre-exposure appears to augment the response of tumor cells to radiation.

High percentage of Cancer Stem cells in metastatic locations: Upregulation of cicBIRC6 in highly metastatic breast Cancer Subline

BACKGROUND

Metastasis is a devastating complication of breast cancer. Cancer relapse and metastasis are associated with cancer stem cells. CicBIRC6 is a circular RNA that is proposed to be involved in the stemness of stem cells. In breast cancer, metastatic tumor cells have higher stem cell properties. In the present study, we evaluate the expression of cicBIRC6 in these cells.

METHODS

After the development of a syngeneic animal model of TNBC, primary breast cancer cells named 4T1T were isolated from the tumor mass. Highly metastatic tumor cells named 4T1B and 4T1L were isolated and expanded from brain metastasis lesions and lungs of cancerous mice respectively. Sphere formation ability in metastatic and primary tumor cells was evaluated separately. The quantitative real-time polymerase chain reaction was performed to analyze the expression of cicBIRC6 in primary and metastatic tumor cells.

RESULTS

Our data revealed that, sphere formation ability among metastatic tumor cells was significantly higher. Surprisingly expression of cicBIRC6 was significantly upregulated in these metastatic tumor cells. In comparison with 4T1T, cicBIRC6 was upregulated 5.7 and 3.5 times in 4T1B and 4T1L respectively.

CONCLUSION

These findings provided important insights regarding the molecular properties of metastatic tumor cells and can be used for designing a targeted therapeutic strategy in combat with these cells.

Evaluation of anticancer effects of frankincense on breast cancer stem-like cells

BACKGROUND

Relapse and metastasis in breast cancer are linked to cancer stem cells (CSCs) resistant to anticancer therapies. The presence of cancer stem-like cells (CSLCs) and their ability to self-renew is determined by in vitro spheroid formation.

AIMS

Many studies have found that frankincense has anticancer impacts, although these effects on breast CSLCs have never been evaluated.

METHODS AND RESULTS

A population of heterogeneous breast tumor cells was extracted from the tumor mass after generating an animal model of triple-negative breast cancer (TNBC). Spheroid formation was used as an in vitro assay to determine the existence of CSLCs in these cells. MTT assay was used to determine frankincense's cytotoxic activity. An annexin V- propidium iodide (PI) staining and scratch test were used to assess the induction of apoptosis and antimetastatic effects of frankincense. The frankincense extract has significant cytotoxic and apoptotic effects on breast CSLCs. Although, the breast CSLCs are more resistant to these impacts than other breast cancer cells.

CONCLUSION

Our study is the first report that indicates that frankincense extract has anticancer properties in breast CSLCs. Compared to many anticancer chemicals, which have limited potential to battle cancer stem cells, frankincense is an appropriate option to combat breast CSCs.