CHANGES IN RADIATION SENSITIVITY OF HUMAN OSTEOSARCOMA CELLS AFTER P53 INTRODUCTION

Human osteosarcoma SAOS-2 cells, which have a deletion in p53 gene, we re transfected with plasmid pMSV neop53 containing human p53 cDNA and neomycin-resistance gene. Three clones (SAOS-MC10, SAOS-MC11 and SAOS- MC43) among 60 clones expressed p53 mRNA. No p53 protein was observed in SAOS-MC10, while SAOS-MC11 and SAOS-MC43 produced p53 protein. The molecular weight of p53 protein in SAOS-MC43 was lower than that in SA OS-MC11. SAOS-MC11 and SAOS-MC43 were more sensitive and more resistan t, respectively, to ionizing radiation than the parental SAOS-2. We su ggest that exogenous p53 protein might be one of the factors determini ng cellular radiosensitivity.