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Manou D, Bouris P, Kletsas D, Götte M, Greve B, Moustakas A, Karamanos NK, Theocharis AD. Serglycin activates pro-tumorigenic signaling and controls glioblastoma cell stemness, differentiation and invasive potential. Matrix Biol Plus 2020; 6-7:100033. [PMID: 33543029 PMCID: PMC7852318 DOI: 10.1016/j.mbplus.2020.100033] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 03/06/2020] [Accepted: 03/06/2020] [Indexed: 12/11/2022] Open
Abstract
Despite the functional role of serglycin as an intracellular proteoglycan, a variety of malignant cells depends on its expression and constitutive secretion to advance their aggressive behavior. Serglycin arose to be a biomarker for glioblastoma, which is the deadliest and most treatment-resistant form of brain tumor, but its role in this disease is not fully elucidated. In our study we suppressed the endogenous levels of serglycin in LN-18 glioblastoma cells to decipher its involvement in their malignant phenotype. Serglycin suppressed LN-18 (LN-18shSRGN) glioblastoma cells underwent astrocytic differentiation characterized by induced expression of GFAP, SPARCL-1 and SNAIL, with simultaneous loss of their stemness capacity. In particular, LN-18shSRGN cells presented decreased expression of glioma stem cell-related genes and ALDH1 activity, accompanied by reduced colony formation ability. Moreover, the suppression of serglycin in LN-18shSRGN cells retarded the proliferative and migratory rate, the invasive potential in vitro and the tumor burden in vivo. The lack of serglycin in LN-18shSRGN cells was followed by G2 arrest, with subsequent reduction of the expression of cell-cycle regulators. LN-18shSRGN cells also exhibited impaired expression and activity of proteolytic enzymes such as MMPs, TIMPs and uPA, both in vitro and in vivo. Moreover, suppression of serglycin in LN-18shSRGN cells eliminated the activation of pro-tumorigenic signal transduction. Of note, LN-18shSRGN cells displayed lower expression and secretion levels of IL-6, IL-8 and CXCR-2. Concomitant, serglycin suppressed LN-18shSRGN cells demonstrated repressed phosphorylation of ERK1/2, p38, SRC and STAT-3, which together with PI3K/AKT and IL-8/CXCR-2 signaling control LN-18 glioblastoma cell aggressiveness. Collectively, the absence of serglycin favors an astrocytic fate switch and a less aggressive phenotype, characterized by loss of pluripotency, block of the cell cycle, reduced ability for ECM proteolysis and pro-tumorigenic signaling attenuation.
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Key Words
- ALDH1, aldehyde dehydrogenase 1
- Astrocytic differentiation
- CXCR, C-X-C chemokine receptor
- ECM, extracellular matrix
- EMT, epithelial to mesenchymal transition
- ERK, extracellular-signal-regulated kinase
- GFAP, glial fibrillary acid protein
- Glioblastoma
- IL, interleukin
- Interleukins
- MAPK, mitogen-activated protein kinase
- MMPs, metalloproteinases
- PGs, proteoglycans
- PI3K, phosphoinositide 3-kinase
- Proteoglycans
- Proteolytic enzymes
- SRGN, serglycin
- STAT-3, signal transducer and activator of transcription 3
- Serglycin
- Signaling
- Stemness
- TIMPs, tissue inhibitors of metalloproteinases
- uPA, urokinase plasminogen activator
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Affiliation(s)
- Dimitra Manou
- Biochemistry, Biochemical Analysis & Matrix Pathobiology Research Group, Laboratory of Biochemistry, Department of Chemistry, University of Patras, Greece
| | - Panagiotis Bouris
- Biochemistry, Biochemical Analysis & Matrix Pathobiology Research Group, Laboratory of Biochemistry, Department of Chemistry, University of Patras, Greece
| | - Dimitris Kletsas
- Laboratory of Cell Proliferation & Ageing, Institute of Biosciences & Applications, National Centre for Scientific Research ‘Demokritos’, Athens, Greece
| | - Martin Götte
- Department of Gynecology and Obstetrics, University Hospital, Muenster, Germany
| | - Burkhard Greve
- Department of Radiotherapy-Radiooncology, University Hospital, Muenster, Germany
| | - Aristidis Moustakas
- Department of Medical Biochemistry and Microbiology, Science for Life Laboratory, Uppsala University, Sweden
| | - Nikos K. Karamanos
- Biochemistry, Biochemical Analysis & Matrix Pathobiology Research Group, Laboratory of Biochemistry, Department of Chemistry, University of Patras, Greece
| | - Achilleas D. Theocharis
- Biochemistry, Biochemical Analysis & Matrix Pathobiology Research Group, Laboratory of Biochemistry, Department of Chemistry, University of Patras, Greece
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