LOCALIZATION OF ESTROGEN-RECEPTORS IN INTERSTITIAL-CELLS OF HAMSTER-KIDNEY AND IN ESTRADIOL-INDUCED RENAL TUMORS AS EVIDENCE OF THE MESENCHYMAL ORIGIN OF THIS NEOPLASM
Hk. Bhat et al., LOCALIZATION OF ESTROGEN-RECEPTORS IN INTERSTITIAL-CELLS OF HAMSTER-KIDNEY AND IN ESTRADIOL-INDUCED RENAL TUMORS AS EVIDENCE OF THE MESENCHYMAL ORIGIN OF THIS NEOPLASM, Cancer research, 53(22), 1993, pp. 5447-5451
The mechanism of estrogen-induced and -dependent kidney carcinogenesis
in Syrian hamsters and the cell of origin of the tumor are not well u
nderstood; they have been investigated in this study by mapping the ce
llular locations of estrogen receptor (ER) in estrogen-dependent tumor
s, in kidney tissue of hamsters treated with estradiol for 0.5 and 5.5
months, and in kidneys of age-matched controls. To validate the metho
ds used, receptors have also been localized in uteri of hamsters and r
ats and in female hamster kidneys. ERs have been identified in cryosta
t sections by immunocytochemical techniques using an affinity-purified
ER antibody, ER-715. Nuclei of tumors were intensely stained for ERs.
In estrogen-treated kidneys and in controls, ER protein was identifie
d in interstitial cells and capillaries, in arteries, and in renal cor
puscles, particularly in podocytes and in the parietal layers surround
ing the renal corpuscles. There was no ER protein in tubular epithelia
even when tubuli were surrounded by tumor cells. The ER distribution
in female hamster kidneys closely matched that in male kidneys. Howeve
r, the staining intensity was stronger in female than in male kidneys.
In hamster uteri, there was an intense ER-positive reaction in the nu
clei of stroma, in stromal vessels, and in the luminal epithelia as de
monstrated previously by others in rat uteri. ER mRNA has also been de
monstrated by Northern blot analysis in estrogen-treated kidneys which
contained tumors but was undetectable in untreated kidneys. The local
ization of ERs in estrogen-dependent tumors and in interstitial cell t
ypes but not in tubular epithelia supports previous conclusions of an
interstitial origin of estrogen-induced hamster kidney tumors.