Crescimento do câncer de mama receptor de hormônio dependente: contribuições de um modelo experimental

Si bien los estrógenos han demostrado tener un rol protagónico en el cáncer de mama, hoy se sabe que la progesterona, así como sus derivados sintéticos, ejercen roles proliferativos tanto en la glándula mamaria normal como neoplásica. Utilizando un modelo experimental de cáncer mamario murino, iniciado en la Academia Nacional de Medicina y trasladado al IBYME en el año 1995, demostramos la importancia de los fibroblastos asociados a tumor en la provisión de factores de crecimiento que activan en forma ligando-independiente a los receptores de progesterona (RPs) en las células tumorales. En este artículo mencionamos la importancia por un lado de la proporción de isoformas del RP en la determinación de la respuesta al tratamiento hormonal, y por otro, los mecanismos por los cuales el factor de crecimiento fibroblástico 2 (FGF2) estromal participaría en el crecimiento tumoral imitando la acción de la hormonaIt is well known that estrogens are key players regulating breast cancer growth. In addition, there is compelling evidence pointing out that progestins induce proliferative effects in normal and in neoplastic mammary glands. Using a murine breast cancer model, first developed in the National Academy of Medicine in Buenos Aires, and then moved to the IBYME in 1995, we demonstrated that carcinoma associated fibroblasts provide growth factors such as fibroblast growth factor 2 (FGF2), which are involved in the ligand independent activation of progesterone receptors (PR) of tumor cells. This article briefly describes, on one hand, the relevance of the evaluation of the PR isoform ratio to predict hormone responsiveness, and on the other hand, the mechanisms by which stromal FGF2 mimics the effects of progesterone to stimulate tumor growth.Embora os estrógenos tenham demonstrado ter um papel protagônico no câncer de mama, hoje se sabe que a progesterona, bem como seus derivados sintéticos, exerce papéis proliferativos tanto na glândula mamária normal quanto neoplá- sica. Utilizando um modelo experimental de câncer mamário murino, iniciado na Academia Nacional de Medicina e trasladado ao IBYME no ano 1995, demonstramos a importância dos fibroblastos associados a tumor na provisão de fatores de crescimento que ativam em forma ligando-independente os receptores de progesterona (RPs) nas células tumorais. Neste artigo mencionamos a importância, de um lado, da proporção de isoformas do RP na determinação da resposta ao tratamento hormonal, e do outro, dos mecanismos pelos quais o fator de crescimento fibroblástico 2 (FGF2) estromal participaria no crescimento tumoral imitando a ação do hormônio.Fil: Lanari, Claudia Lee Malvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Novaro, Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Lamb, Caroline Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Fabris, Victoria Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Rojas, Paola Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Giulianelli, Sebastian Jesus. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Gorostiaga, Maria Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Wargon, Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Guillardoy, Tomás. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Polo, Maria Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Riggio, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Sequeira, Gonzalo Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Sahores, Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Pampena, María Betina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentin

Interaction between FGFR-2, STAT5, and progesterone receptors in breast cancer

Fibroblast growth factor (FGF) receptor 2 (FGFR-2) polymorphisms have been associated with an increase in estrogen receptor and progesterone receptor (PR)-positive breast cancer risk; however, a clear mechanistic association between FGFR-2 and steroid hormone receptors remains elusive. In previous works, we have shown a cross talk between FGF2 and progestins in mouse mammary carcinomas. To investigate the mechanisms underlying these interactions and to validate our findings in a human setting, we have used T47D human breast cancer cells and human cancer tissue samples. We showed that medroxyprogesterone acetate (MPA) and FGF2 induced cell proliferation and activation of ERK, AKT, and STAT5 in T47D and in murine C4-HI cells. Nuclear interaction between PR, FGFR-2, and STAT5 after MPA and FGF2 treatment was also showed by confocal microscopy and immunoprecipitation. This effect was associated with increased transcription of PRE and/or GAS reporter genes, and of PR/STAT5-regulated genes and proteins. Two antiprogestins and the FGFR inhibitor PD173074, specifically blocked the effects induced by FGF2 or MPA respectively. The presence of PR/FGFR-2/ STAT5 complexes bound to the PRE probe was corroborated by using NoShift transcription and chromatin immunoprecipitation of the MYC promoter. Additionally, we showed that T47D cells stably transfected with constitutively active FGFR-2 gave rise to invasive carcinomas when transplanted into NOD/SCID mice. Nuclear colocalization between PR and FGFR-2/STAT5 was also observed in human breast cancer tissues. This study represents the first demonstration of a nuclear interaction between FGFR-2 and STAT5, as PR coactivators at the DNA progesterone responsive elements, suggesting that FGFRs are valid therapeutic targets for human breast cancer treatment. ©2011 AACR.Fil: 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: Guillardoy, Tomás. 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: Vaque, José P.. National Institutes of Health; Estados UnidosFil: Gutkind JS. National Institutes of Health; Estados UnidosFil: Vanzulli, Silvia. Academia Nacional de Medicina de Buenos Aires; ArgentinaFil: Martins, Rubén. Clínica Bancaria; ArgentinaFil: Zeitlin, Eduardo. Clínica Bancaria; 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: 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

Fibroblast Growth Factor Receptors (FGFRs) in Human Sperm: Expression, Functionality and Involvement in Motility Regulation.

Fibroblast growth factors receptors (FGFRs) have been widely characterized in somatic cells, but there is scarce evidence of their expression and function in mammalian gametes. The objective of the present study was to evaluate the expression of FGFRs in human male germ cells, to determine sperm FGFR activation by the FGF2 ligand and their participation in the regulation of sperm motility. The expression of FGFR1, 2, 3 and 4 mRNAs and proteins in human testis and localization of these receptors in germ cells of the seminiferous epithelium was demonstrated. In ejaculated sperm, FGFRs were localized to the acrosomal region and flagellum. Sperm exposure to FGF2 caused an increase in flagellar FGFR phosphorylation and activation of extracellular signal-regulated kinase (ERK) and protein kinase B (PKB or Akt) signaling pathways. Incubation with FGF2 led to a significant increase in the percentage of total and progressive sperm motility, as well as in sperm kinematics. All responses were prevented by sperm preincubation with BGJ398, a specific inhibitor of FGFR tyrosine kinase activity. In addition to confirming the expression of FGFRs in germ cells of the human testis, our study describes for the first time the presence, localization and functionality of human sperm FGFRs, and provides evidence of the beneficial effect of FGF2 upon sperm motility

Localization of FGFRs in human seminiferous epithelium.

<p>Immunohistochemical analysis of FGFRs in human testis using anti FGFR antibodies; rabbit IgG was included as control. The specimens were counterstained with hematoxylin. S: Sertoli cell, Sg: spermatogonia, Sc: spermatocyte, St: spermatid. Arrows indicate immunoreactivity for FGFRs in the flagellum of elongating/elongated spermatids and the arrow head indicates FGFR4 immunoreactivity in spermatid acrosome. Bar: 20 μm.</p

Activation of FGFR-related intracellular pathways in sperm exposed to FGF2.

<p>Sperm were incubated for a total 4-h period and exposed to FGF2 (0, 1, 10 and 100 ng/ml) for the last 15 min. In some aliquots, sperm were incubated for 15 min with BGJ398 (0.1 μM) before the addition of FGF2. (<b>A</b>) Immunolocalization of pERK and pAkt in sperm incubated in the absence of FGF2 (Control), with 100 ng/ml FGF2, and with BGJ398 + 100 ng/ml FGF2. Sperm were processed for immunocytochemistry, stained with anti pERK or pAkt and FITC-conjugated secondary antibodies; nuclei were stained with propidium iodide. Bar: 10 μm. (<b>B</b>) Percentage of sperm cells stained with anti pERK and anti pAkt after exposure to FGF2 in the absence (<b>left</b>) or presence of BGJ398 (<b>right</b>). Results are expressed as mean ± SEM, n = 4. * <i>P</i> < 0.05; ** <i>P</i> < 0.01 compared with Control. (<b>C</b>) Phosphorylation of ERK and Akt assessed by Western immunoblotting. Protein extracts from human sperm were subjected to SDS-PAGE and Western immunoblotting using anti pERK, ERK, pAkt and Akt antibodies. The estimated molecular weights of the protein bands are indicated on the right. (<b>D</b>) Densitometric analysis of Western immunoblotting results for pERK normalized to ERK and pAkt normalized to Akt. Results are expressed as mean ± SEM, n = 5 for ERK and n = 5 for Akt. * <i>P</i> < 0.05 and ** <i>P</i> < 0.01 compared with Control.</p

Localization of FGFRs in human sperm.

<p>Sperm cells were stained with anti FGFR1, FGFR2, FGFR3 and FGFR4 or rabbit IgG and a secondary antibody labeled with Cy3. The corresponding fields stained with FITC-PSA to assess acrosomal status are shown. Bar: 10 μm. On the right, a representative image of individual sperm is depicted; (<b>A</b>) sperm stained with anti FGFR antibody and Cy3-conjugated secondary antibody, (<b>B</b>) FITC-PSA, (<b>C</b>) merge.</p

Effect of sperm incubation with FGF2 on sperm motility.

<p>Sperm were incubated with 0, 10 and 100 ng/ml FGF2 in the absence or in the presence of 0.1 μM BGJ398 and subjected to computer-assisted sperm analysis. (<b>A</b>) Percentages of progressive (Grade a + b) and total motility (Grade a + b + c) for aliquots incubated in the absence (<b>left</b>) or in the presence of BGJ398 (<b>right</b>). Results are expressed as mean ± SEM, n = 5. ** <i>P</i> < 0.01 compared with Control. (<b>B</b>) Individual recordings of the effect of sperm incubation with FGF2 (0, 10 and 100 ng/ml) on the percentage of total sperm motility in samples with low and high sperm motility. Each sample is identified with a different symbol (n = 12). (<b>C</b>) The percentages of sperm with Grade a, b, c and d motility in each condition (as defined in Materials and Methods) is depicted. * <i>P</i> < 0.05; ** <i>P</i> < 0.01 compared with the same Grade in Control (n = 12).</p

Expression of FGFRs in human testis and sperm.

<p>(<b>A</b>) Messenger RNA expression of testicular and sperm FGFRs assessed by RT-PCR. Messenger RNA extracted from MCF7 cells served as positive controls; negative controls without reverse transcriptase (RT Control) and without template (PCR Control) are shown. The amplicon sizes are indicated on the right. (<b>B</b>) Detection of testis and sperm FGFR protein forms using Western immunoblotting. Protein extracts from human testis and sperm were subjected to SDS-PAGE and Western immunoblotting using anti FGFR antibodies or rabbit IgG as control. The estimated molecular weights of the protein bands are indicated on the right. The experiments were performed at least 3 times obtaining similar results. Typical results are shown.</p

Activation of sperm FGFRs in response to FGF2.

<p>Localization of sperm pFGFRs by immunocytochemistry. Sperm were incubated for 4 h and exposed to FGF2 (0, 1, 10 and 100 ng/ml) for the last 15 min. In some aliquots, sperm were incubated for 15 min with BGJ398 (0.1 μM) before the addition of FGF2. Sperm were processed for immunocytochemistry, stained with anti pFGFR and FITC-conjugated secondary antibody; nuclei were stained with propidium iodide. (<b>A</b>) pFGFR immunolocalization in sperm incubated in the absence of FGF2 (Control), with 100 ng/ml FGF2, and with BGJ398 + 100 ng/ml FGF2. Bar: 10 μm. (<b>B</b>) Percentage of sperm cells stained with anti pFGFR antibody after exposure to different concentrations of FGF2 in the absence (<b>left</b>) or presence of BGJ398 (<b>right</b>). Results are expressed as mean ± SEM, n = 4. * <i>P</i> < 0.05; ** <i>P</i> < 0.01 compared with Control.</p