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Estradiol and its metabolites 4‐hydroxyestradiol and 2‐hydroxyestradiol induce mutations in human breast epithelial cells
Author(s) -
Fernandez Sandra V.,
Russo Irma H.,
Russo Jose
Publication year - 2005
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.21590
Subject(s) - loss of heterozygosity , antiestrogen , carcinogen , biology , estrogen , endocrinology , medicine , neoplastic transformation , microbiology and biotechnology , carcinogenesis , allele , cancer research , chemistry , tamoxifen , breast cancer , gene , cancer , genetics
An elevated incidence of breast cancer in women has been associated with prolonged exposure to high levels of estrogens. Our laboratory demonstrated that treatment of the immortalized human breast epithelial cells MCF‐10F with 17β‐estradiol (E 2 ), 4‐hydroxyestradiol (4‐OHE 2 ) or 2‐hydroxyestradiol (2‐OHE 2 ) induces phenotypical changes indicative of neoplastic transformation. MCF‐10F cells treated with E 2 , 4‐OHE 2 or 2‐OHE 2 formed colonies in agar methocel and lost their ductulogenic capacity in collagen, expressing phenotypes similar to those induced by the carcinogen benzo[ a ]pyrene. To investigate whether the transformation phenotypes were associated with genomic changes, cells treated with E 2 , 4‐OHE 2 or 2‐OHE 2 at different doses were analyzed using microsatellite markers. Since microsatellite instability (MSI) and loss of heterozygosity (LOH) in chromosomes 13 and 17 have been reported in human breast carcinomas, we tested these parameters in MCF‐10F cells treated with E 2 , 2‐OHE 2 , or 4‐OHE 2 alone or in combination with the antiestrogen ICI182780. MCF‐10F cells treated with E 2 or 4‐OHE 2 , either alone or in combination with ICI182780, exhibited LOH in the region 13q12.3 with the marker D13S893 located at ∼0.8 cM telomeric to BRCA2 . Cells treated with E 2 or 4‐OHE 2 at doses of 0.007 and 70 nM and 2‐OHE 2 only at a higher dose (3.6 μM) showed a complete loss of 1 allele with D13S893. For chromosome 17, differences were found using the marker TP53‐Dint located in exon 4 of p53 . Cells treated with E 2 or 4‐OHE 2 at doses of 0.007 nM and 70 nM and 2‐OHE 2 only at a higher dose (3.6 μM) exhibited a 5 bp deletion in p53 exon 4. Our results show that E 2 and its catechol estrogen metabolites are mutagenic in human breast epithelial cells. ICI182780 did not prevent these mutations, indicating that the carcinogenic effect of E 2 is mainly through its reactive metabolites 4‐OHE 2 and 2‐OHE 2, with 4‐OHE 2 and E 2 being mutagenic at lower doses than 2‐OHE 2 . © 2005 Wiley‐Liss, Inc.