Osteoclast differentiation macrophage colony-stimulating

Osteoclast-like multinucleated cells can be differentiated in vitro from cocultures of mouse bone marrow cells and calvarial osteoblastic cells by treatment with the osteotropic factor la,25-dihydroxyvitamin D3 (1,25 (0H)2D3) (Miura et al, 2002). It has been shown that RANKL induces osteoclast formation in a culture of bone marrow cells in the presence of macrophage colony-stimulating factor without the need for osteoblasts. A mouse macrophage RAW264 cells are also known to differentiate into osteoclasts in the presence of RANKL (Hsu et al, 1999). When osteoblast/ stromal cells are stimulated by osteotropic factors such as l,25(OH)2D3, RANKL is expressed and induces the differentiation of osteoclast progenitors by binding to RANK (Jimi et al., 1999). 

Contact with UMR106 rat osteoblast-like cells and the presence of la25-dihydroxyvitamin D3 and human macrophage colony stimulating factor were absolute requirements for differentiation of human breast carcinoma tumour-associated macrophages into mature functional osteoclasts (Quinn et al. 1998). 

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