Chemotherapy Treatment Considerations in Metastatic Breast Cancer

Omega-3 fatty acids: molecular weapons against chemoresistance in breast cancer

Breast cancer is the most commonly diagnosed type of cancer and the leading cause of cancer-related death in women worldwide. Highly targeted therapies have been developed for different subtypes of breast cancer, including hormone receptor (HR)-positive and human epidermal growth factor receptor 2 (HER2)-positive breast cancer. However, triple-negative breast cancer (TNBC) and metastatic breast cancer disease are primarily treated with chemotherapy, which improves disease-free and overall survival, but does not offer a curative solution for these aggressive forms of breast cancer. Moreover, the development of chemoresistance is a major cause of therapeutic failure in this neoplasia, leading to disease relapse and patient death. In addition, chemotherapy's adverse side effects may substantially worsen health-related quality of life. Therefore, to improve the outcome of patients with breast cancer who are undergoing chemotherapy, several therapeutic options are under investigation, including the combination of chemotherapeutic drugs with natural compounds. Omega-3 (ω-3) polyunsaturated fatty acids (PUFAs), including docosahexaenoic and eicosapentaenoic acids, have drawn attention for their antitumoral properties and their preventive activities against chemotherapy-induced toxicities in breast cancer. A literature review was conducted on PubMed using keywords related to breast cancer, omega-3, chemoresistance, and chemotherapy. This review aims to provide an overview of the molecular mechanisms driving breast cancer chemoresistance, focusing on the role of ω-3 PUFAs in these recognized cellular paths and presenting current findings on the effects of ω-3 PUFAs combined with chemotherapeutic drugs in breast cancer management.

Therapeutic potential of brentuximab vedotin in breast cancer and lymphoma via targeted apoptosis and gene regulation

This study was designed to assess the effect of brentuximab vedotin on several breast cancer cell lines in terms of promoting apoptosis and managing cancer progression. Additionally, the study investigated the potential of repurposing this drug for new therapeutic reasons, beyond its original indications. The study evaluates the cytotoxic effects of Brentuximab vedotin across five cell lines: normal human skin fibroblasts (HSF), three breast cancer cell lines (MCF-7, MDA-MB-231, and T-47D), and histiocytic lymphoma (U-937). Brentuximab treatment was administered at four time points (0, 24, 48, and 72 h), with cell viability assessed at each interval. HSF cells, serving as controls, exhibited minimal viability loss (above 70%), indicating limited toxicity in normal fibroblasts. In contrast, MCF-7 and MDA-MB-231 cells demonstrated time-dependent reductions in viability, with a pronounced decline by 72 h, suggesting Brentuximab's efficacy in both ER-positive and triple-negative breast cancer. T-47D cells also showed decreased viability, though at a slower rate. U-937 cells exhibited the most substantial reduction, highlighting Brentuximab's potent activity against hematologic malignancies. Wound healing assays further revealed that Brentuximab significantly impaired the migration and healing capacity of cancer cells compared to untreated controls. Additionally, cell cycle analysis indicated G2/M phase arrest in cancer cells, particularly in MCF-7 and MDA-MB-231, while HSF cells remained largely unaffected. Apoptosis detection confirmed Brentuximab-induced cell death, with significant increases in late apoptosis in cancer lines, especially by 72 h. Gene expression analysis revealed upregulation of pro-apoptotic genes (BAX, Caspase 3, and Caspase 9) in cancer cells, alongside a decrease in anti-apoptotic BCL-2 expression. These findings suggest Brentuximab's selective cytotoxicity against cancer cells and its potential as an effective therapeutic agent, particularly in breast cancer and histiocytic lymphoma.

Beyond endocrine resistance: estrogen receptor (ESR1) activating mutations mediate chemotherapy resistance through the JNK/c-Jun MDR1 pathway in breast cancer

PURPOSE

All patients with metastatic breast cancer (MBC) expressing estrogen receptor-α (ESR1) will eventually develop resistance to endocrine therapies. In up to 40% of patients, this resistance is caused by activating mutations in the ligand-binding domain (LBD) of ESR1. Accumulating clinical evidence indicate adverse outcomes for these patients, beyond that expected by resistance to endocrine therapy. Here we aimed to study the role of ESR1 mutations in conferring chemoresistance in BC cells.

METHODS

MCF-7 cells harboring Y537S and D538G ESR1 mutations (mut-ER) were employed to study the response to chemotherapy drugs, paclitaxel and doxorubicin, using viability and apoptotic assay in vitro, and tumor growth in vivo. JNK/c-Jun/MDR1 pathway was studied using qRT-PCR, western-blot, gene-reporter and ChIP assays. MDR1 expression was analyzed in clinical samples using IHC.

RESULTS

 Cell harboring ESR1 mutations displayed relative chemoresistance compared to WT-ER, evidenced by higher viability and reduced apoptosis as well as resistance to paclitaxel in vivo. To elucidate the underlying mechanism, MDR1 expression was examined and elevated levels were observed in mut-ER cells, and in clinical BC samples. MDR1 is regulated by the c-Jun pathway, and we showed high correlation between these two genes in BC using TCGA databases. Accordingly, we detected higher JNK/c-Jun expression and activity in ESR1-mutated cells, as well as increased occupancy of c-Jun in MDR1 promoter. Importantly, JNK inhibition decreased MDR1 expression and restored sensitivity to chemotherapy.

CONCLUSIONS

Taken together, these data indicate that ESR1 mutations confer chemoresistance through activation of the JNK/MDR1 axis. These finding suggest a novel treatment option for BC tumors expressing ESR1 mutations.

How Shilajit-Based Nanocarriers Alter Classical Doxorubicin Delivery to Breast Cancer Cells (MCF-7 and ZR-75-1)

Chemotherapy has been ineffective in cancer treatment, and efficient delivery of chemotherapeutic agents remains a challenge. In this study, we developed a doxorubicin-loaded shilajit-based nanocarrier (SHN-Dox) using a nanoprecipitation method to enhance Dox uptake into breast cancer cells (MCF-7 and ZR-75-1). After confirmation of the physicochemical properties of the nanocarriers, the cytotoxic and pro-apoptotic effects of SHN-Dox and the production of reactive oxygen species (ROS) were evaluated on breast cancer cells. SHN-Dox showed a spherical shape with a size of 244 nm and a sustainable release profile of Dox. It exhibited high cytotoxicity against MCF-7 and ZR-75-1 cells, effectively inducing DNA fragmentation in these cells. After 24 h of treatment, SHN-Dox increased the apoptosis rate in MCF-7 cells and raised ROS levels. Therefore, SHN-Dox is a promising carrier that might reduce the side effects of Dox on healthy cells and provide a new strategy for clinical cancer treatment.

A bibliometric analysis of metastatic breast cancer: two-decade report (2002-2022)

Background

MBC is a lethal form of breast cancer that arises when cancer cells invade other organs or tissues. The treatment of MBC needs personalized approaches based on the tumor and patient characteristics. The purpose of this paper is to analyze MBC studies from 2002 to 2022 using bibliometrics and to investigate its current situation, main contributors, core journals, highly cited papers, and topic evolution.

Materials and methods

We retrieved data from Web of Science Core Collection (WOSCC). Bibliometric analysis of the included literatures mainly used the following tools: the function of "analyze results" and "citation report" in WoS, Microsoft excel 2021, CiteSpace v.6.1. R6, VOSviewer v.1.6.18, BICOMB v.2.04 and gCLUTO v.1.0.

Results

We found 12,653 articles on MBC research published in 1, 802 journals by 69, 753 authors from 118 countries. The annual output and citation of MBC articles showed a rising trend over time. The United States was the most influential country in MBC research. The most cited journal in this field was The Journal of Clinical Oncology. And the most cited article was by Slamon DJ. The co-word analysis of keywords divides MBC into six research clusters. The hormone receptor-positive MBC and liquid biopsy of MBC are the frontiers research trends. "CDK4/6 inhibitor" had the highest burst strength.

Conclusion

Our bibliometric analysis offers a comprehensive overview of MBC research in the past two decades. It shows the current situation, main contributors, core journals, highly cited papers, and topic evolution of this field. Our study can assist researchers and practitioners to comprehend the development and trends of MBC research and to discover potential directions for future research.