Glucocorticoid-induced growth inhibition with enhanced expression of ductal epithelium of human salivary gland adenocarcinoma cells transplanted into athymic nude mice

The effect of glucocorticoid on growth and the histologic features of adenocarcinoma induced in nude mouse by the inoculation of neoplastic epithelial cells of salivary duct origin (HSG) were studied. Subcutaneous injection of dexamethasone (low-dose group: 0.05 micrograms/g, high-dose group: 0.25 micrograms/g) four times a week for 8 weeks significantly (P less than 0.05) inhibited tumor growth, and in one mouse the tumor had almost completely disappeared by the middle of the sixth week of treatment. In addition, dexamethasone induced an apparent luminal structure in the tissue section of the tumor and enhanced the immunoperoxidase reaction to epithelial membrane antigen. The results indicate that dexamethasone inhibited the proliferation of HSG cells in the nude mouse transplantation system probably by inducing the cellular differentiation of the HSG cells toward the more differentiated ductal epithelia via glucocorticoid receptors.