Effects of human recombinant epidermal growth factor on the growth of MKN-28 human gastric carcinoma transplanted into nude mice.

The effects of human recombinant epidermal growth factor (EGF) on the growth of MKN-28 human gastric carcinoma, transplanted into nude mice were studied. Modulation of tissue cAMP and EGF receptor levels by EGF was also studied to reveal the mechanism of the growth inhibitory effects of EGF. EGF exhibited a dose-dependent growth inhibitory effect on MKN-28 human gastric carcinoma transplanted into nude mice. Local injection of 2 ng of EGF moderately inhibited the growth of MKN-28 gastric carcinoma, while injections of 20 ng, 200 ng and 2 micrograms of EGF significantly inhibited tumour growth. EGF decreased tissue cAMP levels in a dose-dependent manner within 24 h after EGF injection. On the other hand, EGF increased the EGF receptor levels up to two or three fold within 24 h after EGF injection. Conversely, the EGF receptor affinity for EGF decreased according to the increase in EGF receptor levels.