Properties of two sublines derived from rat prostatic adenocarcinoma (Dunning R 3327 tumor)

Rat prostatic tumor (Dunning R 3327 tumor) is a well-differentiated adenocarcinoma of Copenhagen strain rat; its growth is extremely slow and androgen-dependent. Two new sublines (Chiba University A and B; CUA, CUB) were obtained during passages; CUA, squamous cell carcinoma, grew at moderate speed, and CUB grew rapidly, being composed of spindle-shaped cells and large bizarre polygonal cells. Growth of CUA was slightly androgen-dependent, while that of CUB was independent of sex hormones. Activities of acid phosphatase were increased in both CUA and CUB as compared with the original R 3327, so the less differentiated sublines of CUA and CUB showed unusual progression. In contrast, activities of alkaline phosphatase in CUA and CUB were diminished as compared with that of the original tumor. Both androgen and estrogen receptors were detected in the cytosol from R 3327, but there was no detectable amount of androgen and estrogen receptors in CUA. CUB did not show any androgen binding but estrogen binding was observed in the cytosol, though estrogen did not have any detectable effect on the growth of this tumor.