The possible role of hematin and Mossbauer effect in the inhibition of osteosarcoma cell proliferation

Hematin, like many hematoporphyrines and porphyrin derivatives, shows a higher affinity and preferential localization for tumor cells. These properties are particularly interesting in view of their possible applications in tumor treatment. The aim of the present work was to test the capability of porphyrines and resonant low energy gamma rays to produce some kind of selective inhibition of tumor cell proliferation. We investigated the role of hematin to potentiate the killing capability of 14.4 keV resonant gamma rays from a 57Co Mossbauer source. Human osteosarcoma cell cultures 'MG-63' were incubated in the presence or absence of hematin (10-4 to 10-5 M) for 24 hours. They were successively irradiated for 4 hours with 14.4 keV gamma rays from a 3.7 GBq 57Co source. The combined effects of hematin and resonant gamma radiation were then examined and rested statistically for significance. Different degrees of growth inhibition were observed when hematin alone, radiation alone, and hematin plus gamma rays were administered to the cultures. Hematin, at the concentrations of 10-4 M is capable of inhibiting tumor cells growth. While no significant effect is attributable to irradiation alone, hematin plus irradiation show a larger inhibition than that expected for purely additive effects.