Presence of leukaemia inhibitory factor (LIF) and LIF-receptor chain (gp190) in osteoclast-like cells cultured from human giant cell tumour of bone. Ultrastructural distribution

The behaviour of multinucleated giant cells (MNC) obtained from a giant cel l tumour of the tibia and cultured on glass col coverslips or on devitalize d dentin slices was investigated using light and electron microscopy. Cells were studied in the presence or absence of LIF a cytokine known to be invo lved in bone turnover and to act as a growth factor in some solid tumours, The direct effect of LIF on MNC was examined by a post-embedding colloidal gold immunocytochemistry process using human anti-LIF and anti-LIF-receptor (chain gp190) antibodies. After 7 days of culture, the MNC obtained displa yed osteoclast immunocytochemical features, Moreover, these MNC were able t o resorb large amounts of dentin and presented typical features of active o steoclasts. Immunolocalization of LIF and LIF-receptor revealed the presenc e of this cytokine and its receptor within the cytoplasm and nucleus of act ive resorbing MNC. LIF upmodulated MNC number and nucleation but decreased their ability to resorb dentin, The present study suggests that MNC obtaine d from human GCT, currently considered as osteoclast-like cells, are target s for LIF and may be a source of LIF production in this pathological condit ion. (C) 1999 Academic Press.