Abstract
Purpose. Production of active transforming growth factor-β (TGF-β )
by human osteosarcoma may contribute to malignant progression through mechanisms
that include induction of angiogenesis, immune suppression and autocrine growth
stimulation of tumor cell growth.To study events associated with induction of cell proliferation
by TGF-β , we have evaluated the TGF-β pathway in two murine osteosarcoma cell lines, K7
and K12.Results. Northern and immunohistochemical analyses show that each cell
line expressesTGF-β1 and TGF-β3 mRNA and protein. Both cell lines secrete activeTGF-β 1
and display a 30–50% reduction in growth when cultured in the presence of a TGF-β blocking
antibody. Expression of TGF-β receptors TβRI, TβRII and TβRIII is demonstrated by affinity
labeling with