RESUMEN
The consumption of progestins has increased considerably in recent decades, as has their disposal into the environment. These substances can negatively affect the reproduction, physiology, and behavior of non-target organisms, such as fish. We aimed to evaluate the effects of exposure to environmentally relevant concentrations of levonorgestrel-control birth based (1.3, 13.3, 133, and 1330 ng/L) on the development and behavior of zebrafish (Danio rerio) in terms of mortality, hatching, spontaneous movement, and larval and adult behavioral tests. Exposure caused anxiogenic-like behavior in larvae, which persisted in adults, as demonstrated by the light-dark test. In contrast, it caused anxiolytic-like behavior in the novel tank test. There was a high mortality rate at all tested concentrations and increases in the hormone cortisol at 13.3 ng/L that affected the sex ratio. These changes may lead to an ecological imbalance, emphasizing the risk of early exposure to progestins in the environment.
Asunto(s)
Contaminantes Químicos del Agua , Pez Cebra , Humanos , Animales , Femenino , Pez Cebra/fisiología , Levonorgestrel/toxicidad , Progestinas/toxicidad , Larva , Anticonceptivos Orales Combinados/farmacología , Anticoncepción , Contaminantes Químicos del Agua/toxicidad , Embrión no MamíferoRESUMEN
Progesterone receptor (PR) and ErbB-2 bidirectional cross talk participates in breast cancer development. Here, we identified a new mechanism of the PR and ErbB-2 interaction involving the PR induction of ErbB-2 nuclear translocation and the assembly of a transcriptional complex in which ErbB-2 acts as a coactivator of Stat3. We also highlighted that the function of ErbB-2 as a Stat3 coactivator drives progestin-induced cyclin D1 promoter activation. Notably, PR is also recruited together with Stat3 and ErbB-2 to the cyclin D1 promoter, unraveling a new and unexpected nonclassical PR genomic mechanism. The assembly of the nuclear Stat3/ErbB-2 transcriptional complex plays a key role in the proliferation of breast tumors with functional PR and ErbB-2. Our findings reveal a novel therapeutic intervention for PR- and ErbB-2-positive breast tumors via the specific blockage of ErbB-2 nuclear translocation.
Asunto(s)
Neoplasias de la Mama/etiología , Neoplasias de la Mama/metabolismo , Neoplasias Mamarias Experimentales/etiología , Neoplasias Mamarias Experimentales/metabolismo , Receptor ErbB-2/metabolismo , Receptores de Progesterona/metabolismo , Factor de Transcripción STAT3/metabolismo , Transactivadores/metabolismo , Transporte Activo de Núcleo Celular/efectos de los fármacos , Animales , Secuencia de Bases , Neoplasias de la Mama/genética , Neoplasias de la Mama/patología , Línea Celular Tumoral , Proliferación Celular , Femenino , Técnicas de Silenciamiento del Gen , Genes bcl-1 , Humanos , Neoplasias Mamarias Experimentales/genética , Neoplasias Mamarias Experimentales/patología , Acetato de Medroxiprogesterona/toxicidad , Ratones , Ratones Endogámicos BALB C , Progestinas/toxicidad , Regiones Promotoras Genéticas , ARN Interferente Pequeño/genética , Receptor ErbB-2/antagonistas & inhibidores , Receptor ErbB-2/genética , Receptores de Progesterona/antagonistas & inhibidores , Receptores de Progesterona/genética , Factor de Transcripción STAT3/antagonistas & inhibidores , Factor de Transcripción STAT3/genética , Transducción de Señal , Transcripción Genética/efectos de los fármacosRESUMEN
From mouse mammary progestin-dependent (PD) adenocarcinomas induced with medroxyprogesterone acetate (MPA) we developed several in vivo lines that are maintained by subcutaneous syngeneic passages in MPA-treated mice and express estrogen (ER) and progesterone receptors (PR). Although most lines remained PD, with time some progestin-independent (PI) variants arose. Both PD and PI tumors regress with estrogen treatment although estrogen-resistant variants may also arise. The object of this paper was to investigate the reversibility of estrogen-resistance and its possible relation with hormone receptor down-regulation. Tumor regression was induced in a progestin-independent tumor line (BET) by treatment with a 5 mg 17beta-estradiol (E2) silastic pellet. One of the tumors started to grow disclosing an estrogen-resistant pattern of growth. This tumor line (BET-R) was transplanted into E2-treated and untreated animals (n = 4-6), selecting for the next passage tumors growing in treated animals. Seven new sublines were obtained at different passages by selecting for the next passage the tumors that had grown in untreated mice (BET-Ra-BET-Rg), until no tumors grew in E2-treated mice. ER and PR were measured by a ligand-binding, dextran-coated charcoal method using a single saturating point. From the seven sublines initiated, the first four proved to be reversible after 3-6 generation transplantation and the last three did not revert. A difference in PR expression between BET and BET-R (p < 0.05) was registered, but it did not correlate with the specific hormone behavior since two reverted lines had a pattern similar to that of BET and the other two were similar to BET-R. The expression of PR was higher in E2-treated mice (p < 0.05) and highly variable in the parental line. This led us to study the expression of PR at different stages of the estrous cycle. Higher levels of PR were observed in proestrous, estrous, and metestrous (p < 0.05) than in diestrous, and undetectable levels were found in ovariectomized mice. No differences in ER expression were detected during the estrous cycle. It can be concluded that under certain experimental conditions, estrogen-resistance is a reversible phenomenon. The experimental manipulation of hormone resistance may help develop strategies to modify the response to anti-hormones in humans.