EXPRESSION OF THE 100-KDA GLUCOSE-REGULATED PROTEIN (GRP100 ENDOPLASMIN) IS ASSOCIATED WITH TUMORIGENICITY IN A MODEL OF RAT COLON ADENOCARCINOMA/

Resistance to glucose starvation and expression of glucose-regulated p roteins (grp) were studied in a model of rat colon carcinoma. In this model, various clones originating from the same parental tumor showed distinct tumorigenic potential in syngeneic hosts. Some clones were tu morigenic while others were rejected by an immune-based mechanism. It appeared that the more tumorigenic clones were more resistant to gluco se starvation and able to synthesize larger amounts of grp100 than non -tumorigenic clones in response to either glucose starvation or tunica mycin treatment. In contrast, there was no difference in the induced l evels of synthesis of grp78 between tumorigenic and non-tumorigenic cl ones. These results suggest that the ability of cells to synthesize la rge amounts of the stress protein grp100 might allow them to resist ma rginal conditions imposed by fully immunocompetent hosts, thus conferr ing greater tumorigenicity. (C) 1994 Wiley-Liss, Inc.