DIFFERENTIAL EXPRESSION OF NEU MESSENGER-RNA AND PROTEIN IN HAMSTER-KIDNEY AND ESTROGEN-INDUCED KIDNEY TUMORS

An inverse relationship between the expression of the neu oncogene and estrogen receptors has been observed in breast cancer patients. In th is study, we examined neu expression in the estrogen-induced and -depe ndent hamster kidney tumors, in kidney and in controls to evaluate the usefulness of this animal model far studying the regulation of genes important in hormonal cancer. The expression of neu mRNA was analyzed by Northern analysis and Neu oncoprotein localization by immunocytoche mistry. The Neu oncoprotein was detected in several segments of proxim al and distal kidney tubules, the loops of Henle and the parietal epit helial cells of Bowman's capsule but not in the tumor. neu mRNA was ex pressed in renal tissue after estrogen treatment and in untreated cont rols, but not in kidney tumors. The absence of Neu oncoprotein and mRN A from those cell types that have previously been shown to overexpress estrogen receptors in response to estrogen, suggests that the estroge n receptor and neu genes are interdependent in this tumor system, whic h may thus be a useful animal model for studying the regulation of neu by estrogens.