Asunto(s)
Bradicardia/diagnóstico , Bradicardia/etiología , Electrocardiografía , Hiperpotasemia/complicaciones , Anciano , Anciano de 80 o más Años , Bradicardia/tratamiento farmacológico , Quimioterapia Combinada , Femenino , Estudios de Seguimiento , Furosemida/uso terapéutico , Humanos , Hiperpotasemia/diagnóstico , Medición de Riesgo , Índice de Severidad de la Enfermedad , Bicarbonato de Sodio/uso terapéutico , Resultado del TratamientoRESUMEN
We investigated the antitumoral efficacy, endocrine consequences, and molecular mechanisms underlying cell death induced by the Hecate-chorionic gonadotropin (CG)beta conjugate, a fusion protein of a 23-amino acid lytic peptide Hecate with a 15-amino acid (81-95) fragment of the human CGbeta chain. Transgenic (TG) mice expressing the inhibin alpha-subunit promoter (inhalpha)/Simian Virus 40 T-antigen (Tag) transgene, developing luteinizing hormone (LH) receptor (R) expressing Leydig and granulosa cell tumors, and wild-type control littermates were treated either with vehicle, Hecate, or Hecate-CGbeta conjugate for 3 weeks. Hecate-CGbeta conjugate treatment reduced the testicular and ovarian tumor burden (P < .05), whereas a concomitant increase (testis; P < .05) or no change (ovary) in tumor volumes occured with Hectate treatment. A drop in serum progesterone, produced by the tumors, and an increase in LH levels occured in Hecate-CGbeta treated mice, in comparison with vehicle and Hecate groups, providing further support for the positive treatment response. Hecate-CGbeta conjugate induced a rapid and cell-specific membrane permeabilization of LHR-expressing cells in vitro, suggesting a necrotic mode of cell death without activation of apoptosis. These results prove the principle that the Hecate-CGbeta conjugate provides a novel specific lead into gonadal somatic cell cancer therapy by targeted destruction of LHR-expressing tumor cells.
Asunto(s)
Tumor de Células de la Granulosa/terapia , Tumor de Células de Leydig/terapia , Meliteno/análogos & derivados , Receptores de HL/metabolismo , Clorometilcetonas de Aminoácidos/farmacología , Animales , Apoptosis , Northern Blotting , Caspasa 3 , Caspasas/metabolismo , Muerte Celular , Línea Celular Tumoral , Separación Celular , Gonadotropina Coriónica Humana de Subunidad beta/química , Gonadotropina Coriónica Humana de Subunidad beta/uso terapéutico , Modelos Animales de Enfermedad , Activación Enzimática , Femenino , Citometría de Flujo , Humanos , Masculino , Meliteno/química , Meliteno/uso terapéutico , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Microscopía Fluorescente , Necrosis , Neoplasias Ováricas/terapia , Progesterona/sangre , Regiones Promotoras Genéticas , Estructura Terciaria de Proteína , Proteínas Recombinantes de Fusión/metabolismo , Neoplasias Testiculares/terapia , Factores de TiempoRESUMEN
We have analyzed the ontogeny and putative mechanisms of transregulation of LH receptor (LHR) and transcription factor GATA-4, coexpressed during the adrenocortical tumorigenesis of prepubertally gonadectomized transgenic (TG) mice expressing the inhibin alpha-subunit promoter/simian virus 40 T-antigen (inhalpha/Tag) transgene. The onset of adrenal LHR mRNA and protein expression coincided with that of GATA-4 at the age of 4 months and preceded the appearance of discernible adrenal tumors at about 6 months. In situ hybridization and double-immunohistochemistry demonstrated colocalization of the LHR and GATA-4 messages and proteins in the adrenal cortex. A GATA-4 expression plasmid cotransfected with a murine LHR promoter-driven luciferase reporter plasmid, containing a consensus GATA-binding site, induced a dose-dependent significant transactivation of the LHR promoter in nonsteroidogenic human embryonic kidney 293, steroidogenic murine mLTC-1 Leydig cells and in murine adrenal Y-1 cells. The Calpha1 cells derived from an Inhalpha/Tag adrenal tumor did not show this response, apparently due to their high endogenous GATA-4 expression. However, an additional link between GATA-4 and LHR in Calpha1 cells was provided upon the LH/human chorionic gonadotropin stimulation of LHR promoter activity; mutations or deletion of the consensus GATA-4 binding site of the LHR promoter abolished this transactivation. EMSAs further proved GATA-4 binding to the putative consensus GATA recognition site. Our results demonstrate direct interrelationship between LHR and GATA-4 expression during adrenocortical tumorigenesis of the inhalpha/Tag mice. There is apparently a positive and reciprocal feed-forward amplification link between LHR and GATA-4 expression. This mechanism gradually and in synergy with Tag expression leads to formation of the LH-dependent adrenocortical tumors.