TRANSLATION OF NORMAL LIVER mRNA AND ITS TRANSFORMING EFFECTS ON HEPATOMA CELLS IN VITRO

The normal liver mRNA wasisolated by oligo(dT)-cellulose chroma-tography of RNA extracted from liverpolysomes. The isolated mRNA wasproved to be biologically active byalbumin translation in two protein syn-thesizing systems; one was wheat germcell-free protein synthesizing system andthe other was Xenopus oocyte translationsystem. Applying the active liver mRNAto transform hepatoma cells in vitro, itwas observed 1) the mRNA from mouseliver inhibited nucleic acid and proteinsynthesis of mouse ascites hepatoma andthe human liver mRNA was primarilyseen to inhibit the growth slightly ofcultured human hepatoma (BEL-7404);2) albumin synthesis was induced inboth lines of hepatoma respectively bycorresponding liver mRNA, the scatteredribosomes in the cytoplasm of humanhepatoma cells was agglutinated to formpolysomes under electron microscopeexamination; 3) agglutination of humanhepatoma cells by concanavalin A wasweakened, the changed characteristicswere maintained after three subculturesof the hepatoma cells. These experi-mental results indicate that the diffe-rentiated state of hepatoma cells is notfixed and unchanged and mRNA fromnormal liver is able to revert partly thehepatoma cells toward normality. Asfor the mechanism of transformation bymRNA in question, we suppose, it isprobably due to the functioning pro-teins translated by the mRNA addedfrom normal liver, or the mRNA directlyregulating the gene expression at trans-cription level.