Aquaporin 5 (AQP5) expression in breast cancer and its clinicopathological characteristics

The Influence of AQP5 on the Response to Hydrogen Peroxide in Breast Cancer Cell Lines

Breast cancer is a heterogeneous disease with varying responses to therapies. While targeted treatments have advanced, conventional therapies inducing oxidative stress remain widely used. H2O2 has emerged as a therapeutic candidate due to its role in signaling and cell-function regulation. Its transport is tightly regulated through peroxiporins such as AQP5, expression of which is linked to poor prognosis and metastatic spread, and its role in therapy resistance remains underexplored. This study examined AQP5's role in the acute oxidative stress response. We overexpressed AQP5 in breast cancer cell lines with low basal levels-HR+ (MCF7), HER2+ (SkBr-3), and TNBC (SUM 159)-and exposed them to H2O2 for 24 h. We assessed cell viability, intracellular ROS, changes in AQP3 and AQP5, and key antioxidative and cancer-related pathways (NRF2, PI3K/AKT, FOXOs). AQP5 overexpression elicited a cell-type-specific response. H2O2 treatment reduced viability in SkBr-3-AQP5 and MCF7-AQP5 cells, increased ROS levels in MCF7-AQP5, and decreased ROS in SUM 159-AQP5. It also increased AQP3 in MCF7-AQP5 and differentially affected NRF2, FOXOs, and PI3K/AKT signaling, notably activating NRF2/AKR1B10 axis in MCF7-AQP5 and decreasing FOXO1 in SUM 159-AQP5. These findings highlight the need for further research into AQP5's role in the oxidative stress response in breast cancer cells.

The Association of Aquaporins with MAPK Signaling Pathway Unveils Potential Prognostic Biomarkers for Pancreatic Cancer: A Transcriptomics Approach

Pancreatic cancer is one of the most lethal and challenging malignancies. Its severity is primarily linked to the constitutively activated mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathway. Aquaporins (AQPs) are frequently overexpressed in pancreatic cancer, playing crucial roles in cell signaling, and consequently promoting cell migration, proliferation, and invasion. Here, we investigate the transcriptomics of key players in epithelial-mesenchymal transition (EMT) and the MAPK/ERK signaling pathway in pancreatic cancer tissues, correlating them with tumor AQP expression to highlight their potential as diagnostic or prognostic tools. The transcriptomics analysis was conducted in 24 paired pancreatic tumors and adjacent healthy tissues, and analyses were performed considering the patients' age and gender, as well as tumor invasiveness and aggressiveness. Our results revealed strong positive Pearson correlation coefficients between AQP3 and c-Jun, and between AQP5 and CDH1/EGFR in pancreatic tumors but not in healthy tissues, with posterior in vitro confirmation in pancreatic cancer BxPC3 cells, suggesting a shift in the regulatory mechanisms of gene expression that certainly affect the physiology of the tissue, influencing cancer initiation and progression. This study underscores the interplay between AQPs and cancer signaling pathways, opening new avenues for defining novel clinical biomarkers and improving the early detection of pancreatic cancer.

Peroxiporins in Triple-Negative Breast Cancer: Biomarker Potential and Therapeutic Perspectives

Triple-negative breast cancer (TNBC) remains one of the most challenging subtypes since it is initially characterized by the absence of specific biomarkers and corresponding targeted therapies. Advances in methodology, translational informatics, genomics, and proteomics have significantly contributed to the identification of therapeutic targets. The development of innovative treatments, such as antibody-drug conjugates and immune checkpoint inhibitors, alongside chemotherapy, has now become the standard of care. However, the quest for biomarkers defining therapy outcomes is still ongoing. Peroxiporins, which comprise a subgroup of aquaporins, which are membrane pores facilitating the transport of water, glycerol, and hydrogen peroxide, have emerged as potential biomarkers for therapy response. Research on peroxiporins reveals their involvement beyond traditional channeling activities, which is also reflected in their cellular localization and roles in cellular signaling pathways. This research on peroxiporins provides fresh insights into the mechanisms of therapy resistance in tumors, offering potential avenues for predicting treatment outcomes and tailoring successful TNBC therapies.

The Involvement of Peroxiporins and Antioxidant Transcription Factors in Breast Cancer Therapy Resistance

Breast cancer is still the leading cause of death in women of all ages. The reason for this is therapy resistance, which leads to the progression of the disease and the formation of metastases. Multidrug resistance (MDR) is a multifactorial process that leads to therapy failure. MDR involves multiple processes and many signaling pathways that support each other, making it difficult to overcome once established. Here, we discuss cellular-oxidative-stress-modulating factors focusing on transcription factors NRF2, FOXO family, and peroxiporins, as well as their possible contribution to MDR. This is significant because oxidative stress is a consequence of radiotherapy, chemotherapy, and immunotherapy, and the activation of detoxification pathways could modulate the cellular response to therapy and could support MDR. These proteins are not directly responsible for MDR, but they support the survival of cancer cells under stress conditions.