The Role of Redox-Regulating Enzymes in Inoperable Breast Cancers Treated with Neoadjuvant Chemotherapy

Multidisciplinary and Tailored Treatment of Locally Advanced Breast Cancer in Progression during Neoadjuvant Chemotherapy: Case Report

Locally advanced breast cancer (LABC) is a complex disease that requires a multidisciplinary approach. Neoadjuvant chemotherapy (NAC) is usually performed in order to achieve loco-regional radical resection; although its importance in the multidisciplinary approach to LABC is well recognized, a small number of patients show Progressive Disease (PD). No standard salvage treatment (ST) has been defined and different strategies can be adopted, such as second-line systemic therapies, radiation therapy, and surgery. Herein, a case of LABC in PD during NAC is reported with a literature review, with the aim of highlighting the importance of a tailored multidisciplinary treatment for each patient.

Nuclear Factor Erythroid 2-Related Factor 2 in Regulating Cancer Metabolism

Significance: Nuclear factor erythroid 2 (NFE2)-related factor 2 (NFE2L2, or NRF2) is a transcription factor predominantly affecting the expression of antioxidant genes. NRF2 plays a significant role in the control of redox balance, which is crucial in cancer cells. NRF2 activation regulates numerous cancer hallmarks, including metabolism, cancer stem cell characteristics, tumor aggressiveness, invasion, and metastasis formation. We review the molecular characteristics of the NRF2 pathway and discuss its interactions with the cancer hallmarks previously listed. Recent Advances: The noncanonical activation of NRF2 was recently discovered, and members of this pathway are involved in carcinogenesis. Further, cancer-related changes (e.g., metabolic flexibility) that support cancer progression were found to be redox- and NRF2 dependent. Critical Issues: NRF2 undergoes Janus-faced behavior in cancers. The pro- or antineoplastic effects of NRF2 are context dependent and essentially based on the specific molecular characteristics of the cancer in question. Therefore, systematic investigation of NRF2 signaling is necessary to clarify its role in cancer etiology. The biggest challenge in the NRF2 field is to determine which cancers can be targeted for better clinical outcomes. Further, large-scale genomic and transcriptomic studies are missing to correlate the clinical outcome with the activity of the NRF2 system. Future Directions: To exploit NRF2 in a clinical setting in the future, the druggable members of the NRF2 pathway should be identified. In addition, it will be important to study how the modulation of the NRF2 system interferes with cytostatic drugs and their combinations.

Early progression of breast cancer during neoadjuvant chemotherapy may predict poorer prognoses

Background: In Finland, breast cancers treated with neoadjuvant chemotherapy (NACT) are usually locally advanced and/or have an inflammatory phenotype. We evaluated early NACT responses in breast tumours and lymph nodes and their correlation with survival.Material and methods: We collected a retrospective dataset of 145 patients with very high-risk but non-metastasised breast cancers that were treated with NACT in a Finnish University Hospital between September 2013 and January 2019. The patients underwent magnetic resonance imaging (MRI) scans before beginning NACT and after every second NACT cycle thereafter.Results: The total pathological complete response rate was only 10.7% and breast cancer-specific survival (BCSS) at 24 months was 93.0%. The 2-year breast cancer-specific survival (BCSS) rate was 93.0%, but this varied from 86.5% for the triple-negative subtype to 100.0% for the luminal A-like subtype. Enlargement of the malignant axillary lymph nodes during the first two NACT cycles was associated with poor BCSS rates in HER2-negative patients (p = .00003 in the univariate analysis; hazard ratio = 26.3; 95% confidence interval = 2.66-259.6; p = .005 in the multivariate analysis). Furthermore, progression in the combined diameters of the breast tumours and axillary lymph nodes during the period between a patient's pre-treatment MRI and her MRI after two NACT cycles was also correlated with worse BCSS rates in both univariate and multivariate analyses.Conclusions: An early MRI assessment after two NACT cycles, specifically of the tumour's axillary lymph nodes, has the potential to predict short-term BCSS in patients with locally advanced HER2-negative breast cancers.

Interplay Between Mitochondrial Peroxiredoxins and ROS in Cancer Development and Progression

Mitochondria are multifunctional cellular organelles that are major producers of reactive oxygen species (ROS) in eukaryotes; to maintain the redox balance, they are supplemented with different ROS scavengers, including mitochondrial peroxiredoxins (Prdxs). Mitochondrial Prdxs have physiological and pathological significance and are associated with the initiation and progression of various cancer types. In this review, we have focused on signaling involving ROS and mitochondrial Prdxs that is associated with cancer development and progression. An upregulated expression of Prdx3 and Prdx5 has been reported in different cancer types, such as breast, ovarian, endometrial, and lung cancers, as well as in Hodgkin's lymphoma and hepatocellular carcinoma. The expression of Prdx3 and Prdx5 in different types of malignancies involves their association with different factors, such as transcription factors, micro RNAs, tumor suppressors, response elements, and oncogenic genes. The microenvironment of mitochondrial Prdxs plays an important role in cancer development, as cancerous cells are equipped with a high level of antioxidants to overcome excessive ROS production. However, an increased production of Prdx3 and Prdx5 is associated with the development of chemoresistance in certain types of cancers and it leads to further complications in cancer treatment. Understanding the interplay between mitochondrial Prdxs and ROS in carcinogenesis can be useful in the development of anticancer drugs with better proficiency and decreased resistance. However, more targeted studies are required for exploring the tumor microenvironment in association with mitochondrial Prdxs to improve the existing cancer therapies and drug development.

Metformin diminishes the unfavourable impact of Nrf2 in breast cancer patients with type 2 diabetes

Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is a major regulator of the oxidative stress response and it is negatively regulated by Kelch-like ECH-associated protein 1 (Keap1). The Keap1–Nrf2 axis has a fundamental role in carcinogenesis. In previous studies, the widely used diabetes drug metformin has appeared to have a critical role in the regulation of Nrf2 function. In this study, we assessed the expression of Nrf2 and Keap1 immunohistochemically in 157 patients with type 2 diabetes who underwent breast cancer surgery with curative intent. In total, 78 (49.7%) of these patients were taking metformin alone or combined with other oral anti-diabetic medication at the time of breast cancer diagnosis. We found that high-level cytoplasmic Nrf2 expression predicted dismal overall survival and breast cancer–specific survival, but only in the patients who were not taking metformin at the time of diagnosis. Similarly, low-level nuclear Keap1 expression had an adverse prognostic value in terms of overall survival and breast cancer–specific survival in patients without metformin. On the other hand, high-level nuclear Keap1 expression was associated with prolonged overall survival and breast cancer–specific survival. The results may be explained in terms of non-functioning or displaced Keap1, although more mechanistic pre-clinical and prospective clinical studies are warranted.