['Dexamethasone (Dx) is often used to alleviate the acute emetic toxicity associated with high dose cisplatin (cDDP) in osteosarcoma patients. However, in other tumour cell types, Dx has been reported to induce partial resistance to anticancer drugs.', 'We examined the effect of Dx on cDDP-induced apoptosis in the HOS human osteosarcoma cell line.', 'Exposure to cDDP, induced apoptosis via the mitochondrial apoptotic pathway as evidenced by cytochrome c release and caspase activation. Pre and cotreatment of HOS cells with Dx reduced cDDP induced apoptosis by 10-25%. Investigation of the mechanisms of this protective effect indicated both the upregulation of the survival factor Akt and a possible direct receptor-mediated action of Dx to attenuate the activation of the mitochondrial apoptotic pathway components.'] Does dexamethasone protect against Cisplatin-induced activation of the mitochondrial apoptotic pathway in human osteosarcoma cells?