Breast cancer is a leading cause of morbidity and mortality among women age 35 and older. Knowledge on the carcinogenic process is limited. Understanding the control of the proliferation of estrogen target cells is crucial to implement preventive, prognostic, diagnostic and therapeutic measures aimed at reducing the morbidity and mortality in these women. We adopted the premise that proliferation is a constitutive, dominant property of cells in metazoa. Thus, the centerpiece of our research is the identification of specific inhibitors of the proliferation of breast tumor cells. We identified human serum albumin (HSA) as such type of inhibitor. Using recombinant HSA we verified that the inhibitory effect was specific regarding the target cell type; among hormones and growth factors, only estrogens overcame this inhibitory effect. Moreover, no other protein was found to produce this inhibitory effect. Because human analbuminemic serum is also able to inhibit the proliferation of MCF7 cells, a paradox emerged. We found evidence consistent with the hypothesis that analbuminemic serum contains as truncated HSA polypeptide, and therefore, HSA may may be considered as a """"""""prohormone"""""""". We will better to resolve this paradox and shed further light on the mechanism of action of HSA and estrogens on the proliferation of breast tumor cells during the period of support.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
2R01CA013410-20A3
Application #
2086141
Study Section
Reproductive Endocrinology Study Section (REN)
Project Start
1995-09-30
Project End
1997-07-31
Budget Start
1995-09-30
Budget End
1996-07-31
Support Year
20
Fiscal Year
1995
Total Cost
Indirect Cost
Name
Tufts University
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
604483045
City
Boston
State
MA
Country
United States
Zip Code
02111
Soto, Ana M; Maffini, Maricel V; Schaeberle, Cheryl M et al. (2006) Strengths and weaknesses of in vitro assays for estrogenic and androgenic activity. Best Pract Res Clin Endocrinol Metab 20:15-33
Soto, Ana M; Sonnenschein, Carlos (2004) The somatic mutation theory of cancer: growing problems with the paradigm? Bioessays 26:1097-107
Powell, Charles E; Soto, Ana M; Michaelson, Cheryl L et al. (2003) Characterization of a plasma membrane-resident albumin-binding protein associated with the proliferation of estrogen-target, serum-sensitive cells. Steroids 68:487-96
Maffini, Maricel V; Geck, Peter; Powell, Charles E et al. (2002) Mechanism of androgen action on cell proliferation: AS3 protein as a mediator of proliferative arrest in the rat prostate. Endocrinology 143:2708-14
Powell, C E; Soto, A M; Sonnenschein, C (2001) Identification and characterization of membrane estrogen receptor from MCF7 estrogen-target cells. J Steroid Biochem Mol Biol 77:97-108
Sonnenschein, C; Soto, A M (2000) Somatic mutation theory of carcinogenesis: why it should be dropped and replaced. Mol Carcinog 29:205-11
Geck, P; Maffini, M V; Szelei, J et al. (2000) Androgen-induced proliferative quiescence in prostate cancer cells: the role of AS3 as its mediator. Proc Natl Acad Sci U S A 97:10185-90
Szelei, J; Soto, A M; Geck, P et al. (2000) Identification of human estrogen-inducible transcripts that potentially mediate the apoptotic response in breast cancer. J Steroid Biochem Mol Biol 72:89-102
Geck, P; Szelei, J; Jimenez, J et al. (1999) Early gene expression during androgen-induced inhibition of proliferation of prostate cancer cells: a new suppressor candidate on chromosome 13, in the BRCA2-Rb1 locus. J Steroid Biochem Mol Biol 68:41-50
Soto, A M; Michaelson, C L; Prechtl, N V et al. (1998) Assays to measure estrogen and androgen agonists and antagonists. Adv Exp Med Biol 444:9-23;discussion 23-8

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