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

Sofía Valla,Nourhan Hassan,Felipe C O B Teixeira,Laura Alaniz,Fiorella Mercedes Spinelli,Daniela Madanes,Nancy Adriana Espinoza-Sánchez,Martin Götte,Burkhard Greve,Carolina Cristina,Daiana Luján Vitale

doi:10.3390/ijms22115874

Abstract

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.

Highlights

Proteoglycans (PGs) are glycoproteins of the cell surface and extracellular matrix (ECM) that are characterized by the presence of highly negatively charged unbranched carbohydrate chains of the glycosaminoglycan (GAG) type [1], which are capable of interacting with a multitude of ligands relevant to normal physiology and tumor progression [2,3].Depending on the composition of their repetitive disaccharide units and the absence or presence of specific sulfation modifications, GAGs comprise the families of the nonsulfated hyaluronan (HA) [4], and the protein-linked heparin/heparan sulfate (HE/HS), chondroitin sulfate/dermatan sulfate (CS/DS) and keratan sulphate (KS) [1,2,5]
To study the impact of Sdc-1 depletion on hyaluronic acid (HA) metabolism, we analyzed the expression of hyaluronan synthases (HASs)-2, one of the main enzymes involved in HA synthesis, by room temperature (RT)-qPCR
The present study highlights an important impact of Sdc-1 depletion on several protumorigenic breast cancer cell properties, including the cancer stem cells (CSCs) phenotype, cell cycle progression, apoptotic resistance, and expression of proangiogenic factors

Summary

Introduction

Proteoglycans (PGs) are glycoproteins of the cell surface and extracellular matrix (ECM) that are characterized by the presence of highly negatively charged unbranched carbohydrate chains of the glycosaminoglycan (GAG) type [1], which are capable of interacting with a multitude of ligands relevant to normal physiology and tumor progression [2,3].Depending on the composition of their repetitive disaccharide units and the absence or presence of specific sulfation modifications, GAGs comprise the families of the nonsulfated hyaluronan (HA) [4], and the protein-linked heparin/heparan sulfate (HE/HS), chondroitin sulfate/dermatan sulfate (CS/DS) and keratan sulphate (KS) [1,2,5]. Proteoglycans (PGs) are glycoproteins of the cell surface and extracellular matrix (ECM) that are characterized by the presence of highly negatively charged unbranched carbohydrate chains of the glycosaminoglycan (GAG) type [1], which are capable of interacting with a multitude of ligands relevant to normal physiology and tumor progression [2,3]. The relevance of altered Sdc-1 expression in breast cancer has been highlighted by several functional studies: previously, we could show that in triple-negative breast cancer cells, Sdc-1 knockdown significantly downregulated the expression of several cytokines and chemokines, and decreased the constitutive activation of STAT3 and NF-κB, thereby increasing the sensitivity of breast cancer cells to radiation therapy [15]. The frequency of the CD44+/CD24- population—marking breast cancer stem cells (CSCs)—was diminished, and the expression and activation of the pro-inflammatory IL-6/STAT3 pathway reduced after Sdc-1 siRNA knockdown [16]

Results

Discussion

Conclusion