Species-specificity of estradiol regulated growth factors in breast cancer.
Recent evidence indicates that autocrine/paracrine mechanisms may mediate the mitogenic effect of estradiol (E2) both in human and experimental breast cancer. However, the species-specificity of E2-regulated growth factors with regard to their biologic action has not been evaluated. To test this issue, we examined, in the soft agar clonogenic assay, the colony-stimulating activity in human breast cancers of conditioned media obtained from rat mammary carcinomas exposed to E2 (rat E2-CM). Of 22 primary human breast cancers plated in soft agar in the absence of serum, 18 (82%) successfully grew with a mean colony number of 62.4 +/- 9.8 (S.E.M.) (range 14-193). Rat E2-CM significantly stimulated colony formation in 10/18 (56%) human breast cancers to 155 +/- 11% (S.E.M.) of control. E2 administration (10(-9) M) in these tumors had a virtually identical overall effect (154 +/- 13% of control colony number). In the remaining eight tumors (44%), neither rat E2-CM nor E2 had, in general, a significant colony-stimulating effect. The growth-promoting action of rat E2-CM and E2 was not influenced by the hormone receptor status of the tumor. These results suggest that E2-regulated growth factors may not be species-specific, at least with regard to their colony-stimulating effects in soft agar.
Manni
A
A
Department of Medicine, Milton S. Hershey Medical Center, Pennsylvania State University, Hershey 17033.
Badger
B
B
Wright
C
C
Glenn
J
J
Ahmed
S R
SR
Demers
L M
LM
D000328:Adult; D000368:Aged; D000818:Animals; D001943:Breast Neoplasms / Q000473:pathology*; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000473:pathology*; D002455:Cell Division; D003114:Colony-Forming Units Assay; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D006133:Growth Substances / Q000502:physiology*; D006801:Humans; D008325:Mammary Neoplasms, Experimental / Q000473:pathology; D008593:Menopause; D008875:Middle Aged; D051381:Rats; D011959:Receptors, Estradiol / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis; D013045:Species Specificity; D014407:Tumor Cells, Cultured / Q000187:drug effects*
D006133:Growth Substances; D011959:Receptors, Estradiol; D011980:Receptors, Progesterone; D004958:Estradiol