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.
Original language | English |
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Journal | Cancer Science |
Volume | 96 |
Issue number | 3 |
Pages (from-to) | 183-90 |
Number of pages | 7 |
ISSN | 1347-9032 |
DOIs | |
Publication status | Published - 2005 |