Association of estrogen receptor-α and progesterone receptor A expression with hormonal mammary carcinogenesis: Role of the host microenvironment
Introduction: Medroxyprogesterone acetate (MPA) induces estrogen receptor (ER)-positive and progesterone receptor (PR)-positive ductal invasive mammary carcinomas in BALB/c mice. We sought to reproduce this MPA cancer model in C57BL/6 mice because of their widespread use in genetic engineering. With...
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2007
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_14655411_v9_n2_p_MonteroGirard http://hdl.handle.net/20.500.12110/paper_14655411_v9_n2_p_MonteroGirard |
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paper:paper_14655411_v9_n2_p_MonteroGirard2023-06-08T16:16:51Z Association of estrogen receptor-α and progesterone receptor A expression with hormonal mammary carcinogenesis: Role of the host microenvironment estrogen receptor alpha progesterone receptor A carcinogen estradiol estrogen receptor alpha hormone medroxyprogesterone acetate progesterone progesterone receptor progesterone receptor A animal cell animal model article breast cancer breast carcinogenesis cancer risk cancer susceptibility carcinogenesis female histology hormonal carcinogenesis hormone determination hormone release hormone resistance hormone response immunochemistry mammary gland microenvironment mouse mouse strain nonhuman protein expression radioimmunoassay risk assessment tissue transplantation Western blotting animal Bagg albino mouse biosynthesis C57BL mouse chemically induced disorder epithelium cell experimental neoplasm metabolism Animals Carcinogens Epithelial Cells Estradiol Estrogen Receptor alpha Female Hormones Mammary Neoplasms, Animal Medroxyprogesterone 17-Acetate Mice Mice, Inbred BALB C Mice, Inbred C57BL Progesterone Radioimmunoassay Receptors, Progesterone Introduction: Medroxyprogesterone acetate (MPA) induces estrogen receptor (ER)-positive and progesterone receptor (PR)-positive ductal invasive mammary carcinomas in BALB/c mice. We sought to reproduce this MPA cancer model in C57BL/6 mice because of their widespread use in genetic engineering. Within this experimental setting, we studied the carcinogenic effects of MPA, the morphologic changes in mammary glands that are induced by MPA and progesterone, and the levels of ER and PR expression in MPA-treated and progesterone-treated mammary glands. Finally, we evaluated whether the differences found between BALB/c and C57BL/6 mouse strains were due to intrinsic differences in epithelial cells. Methods: The carcinogenic effect of MPA was evaluated in C57BL/6 mice using protocols proven to be carcinogenic in BALB/c mice. In addition, BALB/c and C57BL/6 females were treated with progesterone or MPA for 1 or 2 months, and mammary glands were excised for histologic studies and for immunohistochemical and Western blot evaluation of ER and PR. Hormone levels were determined by radioimmunoassay. Isolated mammary epithelial cells were transplanted into cleared fat pads of 21-day-old female Swiss nu/nu mice or control congenic animals. Results: MPA failed to induce mammary carcinomas or significant morphologic changes in the mammary glands of C57BL/6 mice. The expression of ER-α and PR isoform A in virgin mice was surprisingly much higher in BALB/c than in C57BL/6 mammary glands, and both receptors were downregulated in progestin-treated BALB/c mice (P < 0.05). PR isoform B levels were low in virgin control mice and increased after progestin treatment in both strains. ER-β expression followed a similar trend. No differences in hormone levels were found between strains. Surprisingly, the transplantation of the epithelial mammary gland cells of both strains into the cleared fat pads of Swiss (nu/nu) mice abolished the mammary gland morphologic differences and the ER and PR differences between strains. Conclusion: C57BL/6 mammary glands are resistant to MPA-induced carcinogenesis and to hormone action. MPA and progesterone have different effects on mammary glands. Low ER-α and PR-A levels in untreated mammary glands may be associated with a low-risk breast cancer profile. Although we cannot at this time rule out the participation of other, untested factors, our findings implicate the stroma as playing a crucial role in the strain-specific differential hormone receptor expression and hormone responsiveness. © 2007 Montero Girard et al.; licensee BioMed Central Ltd. 2007 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_14655411_v9_n2_p_MonteroGirard http://hdl.handle.net/20.500.12110/paper_14655411_v9_n2_p_MonteroGirard |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
estrogen receptor alpha progesterone receptor A carcinogen estradiol estrogen receptor alpha hormone medroxyprogesterone acetate progesterone progesterone receptor progesterone receptor A animal cell animal model article breast cancer breast carcinogenesis cancer risk cancer susceptibility carcinogenesis female histology hormonal carcinogenesis hormone determination hormone release hormone resistance hormone response immunochemistry mammary gland microenvironment mouse mouse strain nonhuman protein expression radioimmunoassay risk assessment tissue transplantation Western blotting animal Bagg albino mouse biosynthesis C57BL mouse chemically induced disorder epithelium cell experimental neoplasm metabolism Animals Carcinogens Epithelial Cells Estradiol Estrogen Receptor alpha Female Hormones Mammary Neoplasms, Animal Medroxyprogesterone 17-Acetate Mice Mice, Inbred BALB C Mice, Inbred C57BL Progesterone Radioimmunoassay Receptors, Progesterone |
| spellingShingle |
estrogen receptor alpha progesterone receptor A carcinogen estradiol estrogen receptor alpha hormone medroxyprogesterone acetate progesterone progesterone receptor progesterone receptor A animal cell animal model article breast cancer breast carcinogenesis cancer risk cancer susceptibility carcinogenesis female histology hormonal carcinogenesis hormone determination hormone release hormone resistance hormone response immunochemistry mammary gland microenvironment mouse mouse strain nonhuman protein expression radioimmunoassay risk assessment tissue transplantation Western blotting animal Bagg albino mouse biosynthesis C57BL mouse chemically induced disorder epithelium cell experimental neoplasm metabolism Animals Carcinogens Epithelial Cells Estradiol Estrogen Receptor alpha Female Hormones Mammary Neoplasms, Animal Medroxyprogesterone 17-Acetate Mice Mice, Inbred BALB C Mice, Inbred C57BL Progesterone Radioimmunoassay Receptors, Progesterone Association of estrogen receptor-α and progesterone receptor A expression with hormonal mammary carcinogenesis: Role of the host microenvironment |
| topic_facet |
estrogen receptor alpha progesterone receptor A carcinogen estradiol estrogen receptor alpha hormone medroxyprogesterone acetate progesterone progesterone receptor progesterone receptor A animal cell animal model article breast cancer breast carcinogenesis cancer risk cancer susceptibility carcinogenesis female histology hormonal carcinogenesis hormone determination hormone release hormone resistance hormone response immunochemistry mammary gland microenvironment mouse mouse strain nonhuman protein expression radioimmunoassay risk assessment tissue transplantation Western blotting animal Bagg albino mouse biosynthesis C57BL mouse chemically induced disorder epithelium cell experimental neoplasm metabolism Animals Carcinogens Epithelial Cells Estradiol Estrogen Receptor alpha Female Hormones Mammary Neoplasms, Animal Medroxyprogesterone 17-Acetate Mice Mice, Inbred BALB C Mice, Inbred C57BL Progesterone Radioimmunoassay Receptors, Progesterone |
| description |
Introduction: Medroxyprogesterone acetate (MPA) induces estrogen receptor (ER)-positive and progesterone receptor (PR)-positive ductal invasive mammary carcinomas in BALB/c mice. We sought to reproduce this MPA cancer model in C57BL/6 mice because of their widespread use in genetic engineering. Within this experimental setting, we studied the carcinogenic effects of MPA, the morphologic changes in mammary glands that are induced by MPA and progesterone, and the levels of ER and PR expression in MPA-treated and progesterone-treated mammary glands. Finally, we evaluated whether the differences found between BALB/c and C57BL/6 mouse strains were due to intrinsic differences in epithelial cells. Methods: The carcinogenic effect of MPA was evaluated in C57BL/6 mice using protocols proven to be carcinogenic in BALB/c mice. In addition, BALB/c and C57BL/6 females were treated with progesterone or MPA for 1 or 2 months, and mammary glands were excised for histologic studies and for immunohistochemical and Western blot evaluation of ER and PR. Hormone levels were determined by radioimmunoassay. Isolated mammary epithelial cells were transplanted into cleared fat pads of 21-day-old female Swiss nu/nu mice or control congenic animals. Results: MPA failed to induce mammary carcinomas or significant morphologic changes in the mammary glands of C57BL/6 mice. The expression of ER-α and PR isoform A in virgin mice was surprisingly much higher in BALB/c than in C57BL/6 mammary glands, and both receptors were downregulated in progestin-treated BALB/c mice (P < 0.05). PR isoform B levels were low in virgin control mice and increased after progestin treatment in both strains. ER-β expression followed a similar trend. No differences in hormone levels were found between strains. Surprisingly, the transplantation of the epithelial mammary gland cells of both strains into the cleared fat pads of Swiss (nu/nu) mice abolished the mammary gland morphologic differences and the ER and PR differences between strains. Conclusion: C57BL/6 mammary glands are resistant to MPA-induced carcinogenesis and to hormone action. MPA and progesterone have different effects on mammary glands. Low ER-α and PR-A levels in untreated mammary glands may be associated with a low-risk breast cancer profile. Although we cannot at this time rule out the participation of other, untested factors, our findings implicate the stroma as playing a crucial role in the strain-specific differential hormone receptor expression and hormone responsiveness. © 2007 Montero Girard et al.; licensee BioMed Central Ltd. |
| title |
Association of estrogen receptor-α and progesterone receptor A expression with hormonal mammary carcinogenesis: Role of the host microenvironment |
| title_short |
Association of estrogen receptor-α and progesterone receptor A expression with hormonal mammary carcinogenesis: Role of the host microenvironment |
| title_full |
Association of estrogen receptor-α and progesterone receptor A expression with hormonal mammary carcinogenesis: Role of the host microenvironment |
| title_fullStr |
Association of estrogen receptor-α and progesterone receptor A expression with hormonal mammary carcinogenesis: Role of the host microenvironment |
| title_full_unstemmed |
Association of estrogen receptor-α and progesterone receptor A expression with hormonal mammary carcinogenesis: Role of the host microenvironment |
| title_sort |
association of estrogen receptor-α and progesterone receptor a expression with hormonal mammary carcinogenesis: role of the host microenvironment |
| publishDate |
2007 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_14655411_v9_n2_p_MonteroGirard http://hdl.handle.net/20.500.12110/paper_14655411_v9_n2_p_MonteroGirard |
| _version_ |
1768546643272007680 |