Elsevier

Lung Cancer

Volume 48, Issue 2, May 2005, Pages 223-231
Lung Cancer

Expression of YKL-40 by peritumoral macrophages in human small cell lung cancer

https://doi.org/10.1016/j.lungcan.2004.11.011Get rights and content

Summary

YKL-40 is a 40 kDa protein with possible involvement in tissue remodeling, cell proliferation and angiogenesis. Elevated serum YKL-40 levels in patients with metastatic cancers (including small cell lung cancer (SCLC)) are associated with poor prognosis.

The aim of this study was to identify the cellular source of YKL-40 in SCLC patient biopsies and in a panel of 20 human SCLC lines cultured in vitro and in vivo in nude mice.

In general, the SCLC cell lines had no or very limited (human) YKL-40 expression, whereas, by RT-PCR a pronounced murine (i.e., stromal) YKL-40 expression was present in all tumors. YKL-40 mRNA transcripts were detected by in situ hybridization in 9 of 10 biopsies from SCLC patients, and in each case the signal was localized in the peritumoral stroma in cells of typical macrophage morphology (confirmed by a CD68 macrophage specific stain). No YKL-40 mRNA expression was found in the cancer cells, in macrophages infiltrating the solid tumor areas, or in non-malignant tissue. In conclusion, the predominant source of elevated serum YKL-40 in SCLC is peritumoral macrophages.

Introduction

YKL-40 is a secreted 40 kDa extra cellular matrix glycoprotein belonging to the “mammalian chitinase-like proteins” with chitin binding abilities but without chitinase activity [1], [2], [3]. The gene for YKL-40 is known (CHI3L1) and located on chromosome 1q31–q32 [4], [5]. The crystallographic three-dimensional structure of human and goat YKL-40 are described but the site and mode of binding to cell surface receptors are not yet described [2], [3], [6]. The function of YKL-40 is yet elusive but high expression is found during non-pathological processes such as mammary involution and in pathological conditions characterized by inflammation, tissue destruction and development of fibrosis suggesting a major role of YKL-40 in tissue remodeling [7], [8], [9], [10], [11], [12], [13]. Concordantly, YKL-40 stimulates proliferation of connective tissue cells, including fibroblasts, chondrocytes and synovial cells and modulates expression of chemokines and metalloproteases in inflammatory fibroblasts [14], [15], [16]. Furthermore, YKL-40 stimulates GAG synthesis in chondrocytes and exhibits strong binding to heparin [15], [17]. The porcine YKL-40 has been shown to stimulate endothelial cell migration and tube formation, as well as migration and adhesion of vascular smooth muscle cells suggesting an involvement in angiogenesis [18], [19].

Elevated serum concentrations of YKL-40 are found in a subgroup of patients with different types of solid tumors, including several types of adenocarcinomas (breast, colorectal and ovarian), small cell lung cancer (SCLC) and glioblastoma. Furthermore, elevated serum YKL-40 is notably correlated to poor prognosis and short survival [20], [21], [22], [23], [24], [25], [26], [27], [28]. No information exists as to which cells are responsible for the high YKL-40 level in serum in these patients nor has a function in cancer been clarified.

Macrophages, neutrophils, cultured chondrocytes, synovial cells and vascular smooth muscle cells produce YKL-40, whereas fibroblasts do not express YKL-40 [1], [4], [17], [18], [29], [30], [31], [32], [33], [34]. In vitro studies have shown YKL-40 production by cancer cells such as the osteosarcoma cell line MG-63, the myeloid leukemia cell lines THP-1 and HL-60 and glioblastoma cell line U87 (unpublished observation) [5], [30], [35]. Based on these observations it has been suggested that either the cancer cells, macrophages or both cell types might be responsible in part for the elevated YKL-40 in serum of cancer patients.

Since YKL-40 has been shown to be elevated in serum of patients with SCLC, we first investigated the expression of YKL-40 on mRNA and protein level in a panel of 20 human SCLC line cultures in vitro and in vivo grown as solid tumors on nude mice. Secondly, we evaluated whether YKL-40 was expressed by tumor cells and/or macrophages in biopsies from patients with SCLC.

Section snippets

Cell culture

Cell culture reagents were obtained from Invitrogen (UK) unless otherwise mentioned.

The origin and establishment of our 20 SCLC cancer cell lines from 16 patients are described elsewhere [36], [37], [38], [39], [40]. SCLC CPH 54A and CPH 54B were grown in Eagle's MEM. DMS cell lines were grown in Waymouth's medium, except DMS 79, which was grown in RPMI 1640. NCI-H69, NCI-N417, 24H and GLC cell lines were grown in RPMI 1640. All cells were cultured at 37 °C, 5% carbon dioxide and 95–98% humidity

YKL-40 is expressed by stromal cells and not by SCLC cells

A panel of 20 human SCLC cell lines was investigated for YKL-40 mRNA expression by RT-PCR. Hardly any expression was detectable (Fig. 1A). Only one cell line, DMS79, showed weak expression of YKL-40 mRNA. This observation was confirmed on the protein level, where no YKL-40 was detectable by ELISA in the conditioned cell culture media from any of the cell lines.

The same human SCLC cell lines were then propagated as solid tumors on nude mice in order to investigate if an altered microenvironment

Discussion

In previous work it has been reported that a subgroup of patients with SCLC is characterized by elevated serum concentrations of YKL-40 compared to healthy controls and that high serum YKL-40 was associated to short survival [26]. We here show strong evidence that the increased serum YKL-40 levels in SCLC patients are not caused by the cancer cells, which do not express YKL-40 either in vitro or in vivo. Instead, we find pronounced YKL-40 expression in tumor associated macrophages (TAMs) at the

Acknowledgements

Pia Knudsen is thanked for excellent technical assistance. Quidel provided YKL-40 ELISA kits. The study was supported by grants from The Danish Cancer Society and the Danish Medical Research council.

References (52)

  • K.M. Malinda et al.

    Gp38k, a protein synthesized by vascular smooth muscle cells, stimulates directional migration of human umbilical vein endothelial cells

    Exp Cell Res

    (1999)
  • K.C. Nishikawa et al.

    gp38k (CHI3L1) is a novel adhesion and migration factor for vascular cells

    Exp Cell Res

    (2003)
  • J.S. Johansen et al.

    Serum YKL-40: a new potential marker of prognosis and location of metastases of patients with recurrent breast cancer

    Eur J Cancer

    (1995)
  • J.S. Johansen et al.

    High serum YKL-40 level in patients with small cell lung cancer is related to early death

    Lung Cancer

    (2004)
  • K. Shostak et al.

    HC gp-39 gene is upregulated in glioblastomas

    Cancer Lett

    (2003)
  • R.B. Kirkpatrick et al.

    Induction and expression of human cartilage glycoprotein 39 in rheumatoid inflammatory and peripheral blood monocyte-derived macrophages

    Exp Cell Res

    (1997)
  • S.A. Engelholm et al.

    Genetic instability of cell lines derived from a single human small cell carcinoma of the lung

    Eur J Cancer Clin Oncol

    (1985)
  • H. Imabayashi et al.

    Redifferentiation of dedifferentiated chondrocytes and chondrogenesis of human bone marrow stromal cells via chondrosphere formation with expression profiling by large-scale cDNA analysis

    Exp Cell Res

    (2003)
  • T. Suzuki et al.

    Comprehensive gene expression profile of LPS-stimulated human monocytes by SAGE

    Blood

    (2000)
  • C. Nojgaard et al.

    Serum levels of YKL-40 and PIIINP as prognostic markers in patients with alcoholic liver disease

    J Hepatol

    (2003)
  • B.W. Morrison et al.

    neu and ras initiate murine mammary tumors that share genetic markers generally absent in c-myc and int-2-initiated tumors

    Oncogene

    (1994)
  • J.S. Johansen et al.

    A new biochemical marker for joint injuryAnalysis of YKL-40 in serum and synovial fluid

    Br J Rheumatol

    (1993)
  • S. Harvey et al.

    Chondrex: new marker of joint disease

    Clin Chem

    (1998)
  • I. Vind et al.

    Serum YKL-40, a potential new marker of disease activity in patients with inflammatory bowel disease

    Scand J Gastroenterol

    (2003)
  • G. La Montagna et al.

    Cross-sectional evaluation of YKL-40 serum concentrations in patients with systemic sclerosisRelationship with clinical and serological aspects of disease

    J Rheumatol

    (2003)
  • A.D. Recklies et al.

    The chitinase 3-like protein human cartilage glycoprotein 39 (HC-gp39) stimulates proliferation of human connective-tissue cells and activates both extracellular signal-regulated kinase- and protein kinase B-mediated signalling pathways

    Biochem J

    (2002)
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