Hyaluronan Metabolism is Associated with DNA Repair Genes in Breast and Colorectal Cancer. Screening of Potential Progression Markers Using qPCR

Syndecan-1 Depletion Has a Differential Impact on Hyaluronic Acid Metabolism and Tumor Cell Behavior in Luminal and Triple-Negative Breast Cancer Cells

Glycosaminoglycans (GAGs) and proteoglycans (PGs) are major components of the glycocalyx. The secreted GAG and CD44 ligand hyaluronic acid (HA), and the cell surface PG syndecan-1 (Sdc-1) modulate the expression and activity of cytokines, chemokines, growth factors, and adhesion molecules, acting as critical regulators of tumor cell behavior. Here, we studied the effect of Sdc-1 siRNA depletion and HA treatment on hallmark processes of cancer in breast cancer cell lines of different levels of aggressiveness. We analyzed HA synthesis, and parameters relevant to tumor progression, including the stem cell phenotype, Wnt signaling constituents, cell cycle progression and apoptosis, and angiogenic markers in luminal MCF-7 and triple-negative MDA-MB-231 cells. Sdc-1 knockdown enhanced HAS-2 synthesis and HA binding in MCF-7, but not in MDA-MB-231 cells. Sdc-1-depleted MDA-MB-231 cells showed a reduced CD24-/CD44+ population. Furthermore, Sdc-1 depletion was associated with survival signals in both cell lines, affecting cell cycle progression and apoptosis evasion. These changes were linked to the altered expression of KLF4, MSI2, and miR-10b and differential changes in Erk, Akt, and PTEN signaling. We conclude that Sdc-1 knockdown differentially affects HA metabolism in luminal and triple-negative breast cancer model cell lines and impacts the stem phenotype, cell survival, and angiogenic factors.

Initial Identification of UDP-Glucose Dehydrogenase as a Prognostic Marker in Breast Cancer Patients, Which Facilitates Epirubicin Resistance and Regulates Hyaluronan Synthesis in MDA-MB-231 Cells

UDP-glucose-dehydrogenase (UGDH) synthesizes UDP-glucuronic acid. It is involved in epirubicin detoxification and hyaluronan synthesis. This work aimed to evaluate the effect of UGDH knockdown on epirubicin response and hyaluronan metabolism in MDA-MB-231 breast cancer cells. Additionally, the aim was to determine UGDH as a possible prognosis marker in breast cancer. We studied UGDH expression in tumors and adjacent tissue from breast cancer patients. The prognostic value of UGDH was studied using a public Kaplan–Meier plotter. MDA-MB-231 cells were knocked-down for UGDH and treated with epirubicin. Epirubicin-accumulation and apoptosis were analyzed by flow cytometry. Hyaluronan-coated matrix and metabolism were determined. Autophagic-LC3-II was studied by Western blot and confocal microscopy. Epirubicin accumulation increased and apoptosis decreased during UGDH knockdown. Hyaluronan-coated matrix increased and a positive modulation of autophagy was detected. Higher levels of UGDH were correlated with worse prognosis in triple-negative breast cancer patients that received chemotherapy. High expression of UGDH was found in tumoral tissue from HER2^--patients. However, UGDH knockdown contributes to epirubicin resistance, which might be associated with increases in the expression, deposition and catabolism of hyaluronan. The results obtained allowed us to propose UGDH as a new prognostic marker in breast cancer, positively associated with development of epirubicin resistance and modulation of extracellular matrix.