The MPA mouse breast cancer model: evidence for a role of progesterone receptors in breast cancer

More than 60% of all breast neoplasias are ductal carcinomas expressing estrogen (ER) and progesterone receptors (PR). In contrast, most of the spontaneous, chemically or MMTV induced tumors, as well as tumors arising in genetically modified mice do not express hormone receptors. We developed a model of breast cancer in which the administration of medroxyprogesterone acetate (MPA) to BALB/c female mice induces mammary ductal carcinomas with a mean latency of 52 weeks and an incidence of about 80%. These tumors are hormone-dependent, metastatic, express both ER and PR, and are maintained by syngeneic transplants. The model has been further refined to include mammary carcinomas that evolve through different stages of hormone dependency, as well as several hormone-responsive cell lines. In this review, we describe the main features of this tumor model, highlighting the role of PR as a trigger of key signaling pathways mediating tumor growth. In addition, we discussthe relevance of this model in comparison with other currently used breast cancer models pointing out its advantages and limitations and how, this model may be suitable to unravel key questions in breast cancer.Fil: Lanari, Claudia Lee Malvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Lamb, Caroline Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Fabris, Victoria Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Helguero, Luisa A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Soldati, Rocío. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Bottino, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Giulianelli, Sebastian Jesus. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Cerliani, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Wargon, Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Molinolo, Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina. Public Health Service. National Institute Of Health; Estados Unido

Estrogen or antiprogestin treatment induces complete regression of pulmonary and axillary metastases in an experimental model of breast cancer progression

In this paper we demonstrate, using the C7-2-HI metastatic transplantable ductal mammary tumor, that endocrine therapy can induce complete regression of spontaneous lymph node and lung metastases in a mouse model of breast cancer progression. This tumor expresses high levels of estrogen and progesterone receptors and shows a high incidence of early axillary lymph nodes and lung metastases; using this model we had previously shown complete tumor regression of subcutaneous implants. Interestingly, although the metastases showed a more differentiated histology as compared with the primary growth, they underwent complete regression when treated with estrogens or antiprogestins. This phenomenon was associated with sustained cytostasis and apoptosis accompanied by increases in p21 and p27 expression and early tissue remodeling. These results highlight the essential role of PR in regulating cell proliferation in this model as well as its possible use as therapeutic target.Fil: Vanzulli, Silvia. Academia Nacional de Medicina de Buenos Aires; ArgentinaFil: Soldati, Rocío. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Meiss, Roberto. Academia Nacional de Medicina de Buenos Aires; ArgentinaFil: Colombo, Lucas Luis. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología ; ArgentinaFil: Molinolo, Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina. Public Health Service. National Institute Of Health; Estados UnidosFil: Lanari, Claudia Lee Malvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentin

Novel human breast cancer cell lines IBH-4, IBH-6, and IBH-7 growing in nude mice

Breast cancer is the most frequent cancer in women. However, in vivo hormone receptor positive and metas­tatic models are scarce. The aim of the pre­­sent manus­cript was to assess if the novel steroid receptor positive hu­man cell li­nes IBH-4, IBH-6 and IBH-7 developed in our laboratory from primary in­fil­trant duc­tal carcinomas are good mo­dels to study in vivo human breast cancer. Cell lines or tumors were inoculated to nude mice in the presence or ab­­sence of hormone supplementation. Growth was analyzed by ANOVA follo­wed by Tukey-Kra­mer´s test. Steroid hormone expression was assessed by con­focal immuno­fluo­res­cen­ce and Western blotting. The histology of the tu­mors was ana­lyzed. IBH-4 and IBH-6 cells were ino­­­cu­lated to nude mice and 100% of the in­jected mi­ce deve­loped tu­mors in the presence or absence of hor­mo­­ne treat­ment, al­though tamo­xifen inhibited growth. IBH-4 and IBH-6 cell lines in vivo gave rise to poorly diffe­­­ren­tiated carci­no­mas with areas of solid growth and sar­co­­ma­toid areas showing no mor­pho­lo­gical signs of epithe­lial differentiation. Distinct fea­tu­res of ma­lignancy were ob­served. IBH-7 tu­mors in animals receiving estradiol were semi-diffe­ren­­tia­ted ade­no­carcinomas. IBH-7 cells grew only in the pre­­sen­ce of estradiol, but even with hormone addition, the tumor take was 20%. The­se tu­mors me­tas­ta­sized to the uterus and lung and vascular tumor emboli we­re evi­dent. IBH-7 tu­mors were invasive and able to break through the pe­ri­­to­neum. As a conclusion, IBH-4 and IBH-6 are good models for studying tu­mor pro­­gres­sion, whereas IBH-7 is a good model for tumor take, being metastatic and stric­tly estro­gen-dependent.Fil: Bruzzone, Ariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Vanzulli, Silvia. Academia Nacional de Medicina de Buenos Aires; ArgentinaFil: Soldati, Rocío Cinthia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Giulianelli, Sebastian Jesus. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Lanari, Claudia Lee Malvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Luthy, Isabel Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentin

Effects of asPR or RU 486 on MAPK phosphorylation and on ER-α and PR expression

<p><b>Copyright information:</b></p><p>Taken from "Antisense oligonucleotides targeting the progesterone receptor inhibit hormone-independent breast cancer growth in mice"</p><p>Breast Cancer Research 2005;7(6):R1111-R1121.</p><p>Published online 9 Nov 2005</p><p>PMCID:PMC1410760.</p><p>Copyright © 2005 Lamb et al.; licensee BioMed Central Ltd.</p> Immunoblots of ER-α (MC-20; Santa Cruz Biotechnology), total ERK (K-23; Santa Cruz Biotechnology), and pERK (E-4; Santa Cruz Biotechnology) in whole extracts of tumors obtained from animals treated with saline, asPR, or scPR for 5 days. Tumor samples were obtained after day 5 of treatment; tumor growth kinetics is shown in Fig. 2d. Arrows show ERK1 (42 kDa) and ERK2 (44 kDa). PR immunoblots were performed using extracts obtained from mice treated with asPR over 10 days (Ab1; Dr Shyamala). Arrows show the classical PRof 115 kDa and the classical PRof 83 kDa. Immunoblots of ER-α, PR (Ab7; Neomarkers), E-cadherin (E cad; BD Transduction Lab), total ERK, and pERK using wholeextracts of tumors obtained from animals treated with saline or RU 486 for 24 hours. Tumor kinetics are shown in Fig. 2c. A representative Western blot of three is shown. Immunohistochemistry of ER-α and PR (C-20 Santa Cruz) of the same tumor samples used in Western blot studies shown in panel b (125×). Experimental details are described in Materials and method. asPR, antisense oligodeoxynucleotides to progesterone receptors; ER, estrogen receptor; ERK, extracellular signal-regulated kinase; MAPK, mitogen-activated protein kinase; PR, progesterone receptor; scPR, scrambled oligodeoxynucleotides to progesterone receptors

Inhibition of mammary tumor growth by estrogens: Is there a specific role for estrogen receptors alpha and beta?

To evaluate the extent to which each estrogen receptor (ER) subtype contributes to the stimulation or to the inhibition of mammary tumor growth, we evaluated the effects of specific agonists in MC4-L2 cells, which are stimulated by 17β-estradiol (E 2), and in mammary carcinomas of the MPA mouse breast cancer model, which are inhibited by E 2. Both express ERα and ERβ. In MC4-L2 cells, 4,4,4-(4-propyl-(1H)-pyrazole-1,3,5- Triyl)trisphenol (PPT; ERα agonist) and (4-hydroxy-phenyl)-propionitrile (DPN; ERβ agonist) stimulated cell proliferation, whereas the opposite occurred in C4-HI primary cultures. The inhibitory effect was associated with a decrease in ERa and cyclin D1 expression and an increase in progesterone receptor (PR) expression as well as in the Bax/Bcl-xl ratio. In vivo, mice carrying C4-HI or 32-2-HI tumors were treated with E 2, PPT or DPN (3 mg/kg/day) or with vehicle. PPT and DPN inhibited tumor size, as did E 2, during the first 72 h. After a few days, DPN-Treated tumors started to grow again, while PPT-Treated tumors remained quiescent for a longer period of time. A pronounced decrease in the mitotic index and an increase in the apoptotic index was associated with tumor regresion. All treated tumors showed: (a) an increase in integrin α6 and Bax expression, (b) an increased stromal laminin redistribution, and (c) a decrease in ERα, Bcl-xl and Bcl-2 expression (P<0.001). Apoptosis-inducing factor (Aif) expression was increased in DPN-Treated tumors, while active caspase 9 was upregulated in PPT-Treated mice, demonstrating the involvement of the intrinsic apoptotic pathway in estrogen-induced regression in this model. In conclusion, our data indicate that although there may be some preferences for activation pathways by the different agonists, the stimulatory or inhibitory effects triggered by estrogens are cell-context dependent rather than ER isoform dependent. © Springer Science+Business Media, LLC. 2009.Fil: Soldati, Rocío Cinthia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Wargon, Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Cerliani, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Giulianelli, Sebastian Jesus. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Vanzulli, Silvia Inés. Academia Nacional de Medicina de Buenos Aires; ArgentinaFil: Gorostiaga, Maria Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Bolado, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Do Campo, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Molinolo, Alfredo. National Institute of Dental and Craniofacial Research; Estados UnidosFil: Vollmer, Günter. Technische Universitat Dresden; AlemaniaFil: Lanari, Claudia Lee Malvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentin