ABSTRACT
Abstract: Sex hormones play a major role during pubertal growth. Estradiol (E2) and testosterone (T) levels progressively increase during puberty and in the presence of growth hormone (GH), growth velocity increases. Understanding the interactions between sex hormones and GH, may optimize the treatment of pubertal children with growth disorders. The aim of our study was to investigate possible molecular mechanisms which might potentiate longitudinal growth during puberty due to E 2or T combined with GH. We evaluated the GH/JAK2/STAT5 signaling pathway in the human hepatoma cell line HEPG2. Our results suggest that sex hormones potentiate the GH signaling pathway in a dose dependent fashion. Relatively low concentrations of E 2associated with GH induce a substantial activation of the GH pathway, whereas relatively high concentrations of T associated with GH produce a similar effect. These findings are concordant with the physiology of the pubertal growth spurt, which is an early event in girls (when E 2 circulating levels are low), and a late event in boys (when T circulating levels are high).
Resumen: Las hormonas sexuales, modulan el crecimiento durante la pubertad. Los niveles de estradiol (E2) y testosterona (T) aumentan progresivamente durante la pubertad y en combinación con la hormona de crecimiento (GH), producen un incremento en la velocidad de crecimiento en este período conocido como el "estirón puberal". El estudio de la interacción entre las hormonas sexuales y la GH, es de gran importancia para optimizar el tratamiento de niños(as) con alteraciones del crecimiento durante la pubertad. El objetivo de nuestro estudio fue investigar los posibles mecanismos que podrían potenciar el crecimiento longitudinal durante la pubertad, en especial las interacciones entre E 2o T en combinación con GH. Se evaluó la activación de la vía de señalización GH/JAK2/STAT5 frente al estímulo combinado con estas hormonas en cultivos celulares de hepatoma humana HEPG2. Nuestros resultados sugieren que existe un efecto potenciador de las hormonas sexuales sobre la vía de señalización de GH. Observamos que concentraciones relativamente bajas de E2 junto con GH producen una clara activación de la vía de señalización para GH, mientras que concentraciones relativamente altas de T junto con GH producen una activación similar. Estos hallazgos son concordantes con la fisiología del estirón puberal, que es más precoz en niñas (cuando los niveles circulantes de E2 son bajos), y más tardíos en varones (cuando los niveles circulantes de T son altos).
Subject(s)
Humans , Testosterone/physiology , Growth Hormone/physiology , Estradiol/physiology , STAT5 Transcription Factor/physiology , Janus Kinase 2/physiology , PubertyABSTRACT
Objective@#To investigate the effect of silencing GRAMD1A and inhibiting STAT5 signaling pathway on the radiosensitivity of Huh7 cells in order to provide new ideas for the clinical combined therapy of hepatocellular carcinoma.@*Methods@# The Huh7 cells silencing GRAMD1A was constructed by infecting lentivirus and verified by qPCR and Western blot. QPCR and luciferase reporter assays were used to detect the effect of silencing GRAMD1A on the expression of STAT5 and its downstream genes. Colony formation and apoptosis were detected to evaluate the effects of silencing GRAMD1A and STAT5 inhibitor SH-4-54 on cell radiosensitivity.@*Results@#After 2 Gy exposure of the constructed Huh7 cells, the colony formation ability of the silencing GRAMD1A combined irradiation group was significantly lower than that of the negative control combined irradiation group, and the difference was statistically significant (t=8. 494, P<0.05). Silence apoptosis in the GRAMD1A combined irradiation group was significantly increased compared with the negative control combined irradiation group (t=3.560, P<0.05). After silencing GRAMD1A, the radiosensitivity of Huh7 cells was significantly increased, and the expression of STAT5 and its downstream genes was significantly reduced in cells.The survival rate of the SH-4-54 inhibitor combined irradiation group was significantly lower than that of the dimethyl sulfoxide combined irradiation group, and the difference was statistically significant (t=8.660, P<0.05). SH-4-54 inhibited STAT5 after passage, the radiosensitivity of Huh7 cells was significantly increased.@*Conclusions@# Silencing GRAMD1A could significantly enhance the radiosensitivity of Huh7 cells via STAT5 signaling pathway, indicating that GRAMD1A plays an important role in the development and progression of HCC. This finding may provide a new target for HCC therapy.