ISSN:
1573-7217
Keywords:
αTGFs
;
breast cancer cells
;
estrogen
;
estrogen receptor
;
p21ras protein
;
radioimmunoassay
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary Alpha transforming growth factors (αTGFs) were immunologically detected in the concentrated conditioned medium (CM) prepared from four human breast cancer cell lines and from primary cultures of human mammary epithelial cells, and in the tissue extracts prepared from normal, benign, and malignant breast biopsies. Immunoreactive αTGFs were quantitated by a competitive radioimmunoassay (RIA) using affinity-purified polyclonal sheep anti-rat αTGF antibodies which react with human αTGF but not with human epidermal growth factor (EGF). The relative level of RIA-detectable αTGFs in the CM from the breast cancer cell lines MCF-7, ZR-75-1, T47-D, and MDA-MB-231, and from the CM of primary cultures of human mammary epithelial cells, ranged from 0.02 to 0.85 ng/ml. MCF-7 or ZR-75-1 cells grown in the presence of 17β-estradiol (10−8 M) for 48 h were found to release two- to three-fold more αTGFs into their CM than the same cells grown in the absence of estrogen. In detergent extracts prepared from normal breast tissue, a benign fibrocystic lesion, fibroadenomas and primary breast carcinomas, the relative αTGF concentrations were found to range from 1.5 to 6 ng/mg cell protein. No significant correlations were found between the αTGF levels and the pathological state of the tissues, the estrogen receptor status of the tumors, or the relative amounts of theras gene protein p21ras in the tissues as determined by Western immunoblot analysis. The question of biological relevancy of αTGF for human mammary tumors will require further studies on (a) synthesis and turnover of αTGF, (b) the relationship between immunoreactivity and biological activity of αTGF, and (c) differences in biological responsiveness of mammary tumor cells.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01806251
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