Human platelet factor 4 is a direct inhibitor of human osteoblast-like osteosarcoma cell growth.
The effect of purified human platelet factor 4, a platelet alpha-granule protein, on the growth of the human osteoblastic osteosarcoma cell lines Saos-2 and G-292 was investigated. Platelet factor 4 (20 ng/ml to 2 micrograms/ml) caused a significant, dose-dependent inhibition of human osteoblast-like osteosarcoma cell proliferation. Platelet factor 4 exerted its inhibitory effect under all growth conditions tested: serum-free, serum-stimulated and thrombin-stimulated. The platelet factor 4-induced cell inhibition was not associated with a cytotoxic effect on the cells (assessed by lactate dehydrogenase release). The inhibitory effect of platelet factor 4 was not affected by the presence of indomethacin in the cultures, indicating that the effect was prostaglandin-independent. These results suggest that platelet factor 4 has direct antitumor effects and that it may be important in pathological and physiological processes of bone.
Tatakis
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DN
Department of Biological and Biophysical Sciences, School of Dentistry, University of Louisville, KY 40292.
D001769:Blood; D002455:Cell Division; D004247:DNA / Q000096:biosynthesis; D006801:Humans; D007213:Indomethacin / Q000494:pharmacology; D010006:Osteoblasts / Q000473:pathology*; D012516:Osteosarcoma / Q000473:pathology*; D010978:Platelet Factor 4 / Q000494:pharmacology*; D013917:Thrombin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D010978:Platelet Factor 4; D004247:DNA; D013917:Thrombin; D007213:Indomethacin