title: Regulation of YKL-40 expression during genotoxic or microenvironmental stress in human glioblastoma cells.
abstract: YKL-40 is a 40 kDa secreted glycoprotein belonging to the family of 'mammalian chitinase-like proteins', but without chitinase activity. YKL-40 has a proliferative effect on fibroblasts, chondrocytes and synoviocytes, and chemotactic effect on endothelium and vascular smooth muscle cells. Elevated YKL-40 levels are found in serum of patients with diseases characterized by inflammation, fibrosis and tissue remodeling. Several studies have reported that high serum YKL-40 levels in patients with cancer are associated with poor prognosis. YKL-40 expression is strongly elevated in serum and biopsy material from glioblastomas patients. We investigated the expression of YKL-40 in three human malignant glioma cell lines exposed to different types of stress. Whereas a polymerase chain reaction transcript was detectable in all three cell lines, only U87 produced measurable amounts of YKL-40 protein. In U87, hypoxia and ionizing radiation induced a significant increase in YKL-40 after 24-48 h. The hypoxic induction of YKL-40 was independent of HIF1. Etoposide, ceramide, serum depletion and confluence all led to elevated YKL-40. Inhibition of p53 augmented the YKL-40 expression indicating that YKL-40 is attenuated by p53. In contrast, both basic fibroblast growth factor and tumor necrosing factor-alpha repressed YKL-40. These are the first data on regulation of YKL-40 in cancer cells. Diverse types of stress resulted in YKL-40 elevation, which strongly supports an involvement of YKL-40 in the malignant phenotype as a cellular survival factor in an adverse microenvironment.
authors.affiliation: Laboratory of Experimental Oncology, Department of Molecular Pathology, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Nanna
authors.initials: N
authors.lastname: Junker
authors.forename: Julia S
authors.initials: JS
authors.lastname: Johansen
authors.forename: Lasse T
authors.initials: LT
authors.lastname: Hansen
authors.forename: Eva L
authors.initials: EL
authors.lastname: Lund
authors.forename: Paul E G
authors.initials: PE
authors.lastname: Kristjansen
mesh_terms: D054392:Adipokines; D001932:Brain Neoplasms / Q000235:genetics* / Q000473:pathology*; D015687:Cell Hypoxia; D002470:Cell Survival; D000071451:Chitinase-3-Like Protein 1; D004797:Enzyme-Linked Immunosorbent Assay; D015972:Gene Expression Regulation, Neoplastic; D005909:Glioblastoma / Q000235:genetics* / Q000473:pathology*; D006023:Glycoproteins / Q000096:biosynthesis* / Q000235:genetics*; D006801:Humans; D037102:Lectins; D018384:Oxidative Stress; D010641:Phenotype; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured
chemical_list: D054392:Adipokines; C084533:CHI3L1 protein, human; D000071451:Chitinase-3-Like Protein 1; D006023:Glycoproteins; D037102:Lectins