INVESTIGADORES
PODEROSO Juan Jose
congresos y reuniones científicas
Título:
Prolonged inhibition of tumoral progression by in vivo administration of RNA silencing for Akt1 and Trx system
Autor/es:
HERRERA-PÁEZ J J, ALIPPE Y, PEREZ H, COLOMBO L, VANZULLI S, ANTICO-ARCIUCH VG, CARRERAS MC, PODEROSO JJ
Lugar:
Sao Pedro
Reunión:
Congreso; VII Meeting of the SFRBM South American Group. I Sao Paulo Advanced School on Redox Processes in Biomedicine; 2012
Institución organizadora:
SFRBM South American Group
Resumen:
Akt1 is a Ser/Thr kinase involved in cell cycle progression, apoptosis, metabolism, tumorigenesis and tumor growth. Akt1 activity is redox-regulated, since subttle augments in oxidative state increases p-AKT1 levels in mitochondria and thus prevents its translocation to the nucleus. The general concept is that Akt1 prevents cell apoptotic activity, activates proliferation control pathways and controls cell growth, and that activity of Trx1 and 2 gives support to influences of the redox state on mitochondrial Akt phosphorylation. The aim was to inhibit LP07 tumoral growth by means of siRNA for Akt1 (siAkt1) and Trx1 and 2 (siTrx). Experiments were carried out on Balb/C mice of 60 days old, which were subcutaneously inoculated with LP07 lung tumoral cells. Tumors between 30 and 60 mm3 were transfected by electroporation with empty vector (EV), 25 µg of siAkt1 or 20 µg of siTrx1 and 2. Tumors transfected with siAkt showed the highest regression at 48 hours (0.38±0.04 vs 0.18±0.01 mm3 p<0.05), and did not grow during the next 60 days (10 d: EV= 1.8±0.25 vs siAkt= 0.34±0.05; 60 d: siAkt= 0.34±0.06; p<0.05 mm3). TUNEL assay revealed increased apoptosis at 72 hours in tumors treated with siAkt1 (EV= 9.52±0.47%, siAkt1= 16.31±1.20%; p<0.001). Also, treated specimens displayed an increase in survival compared to the control ones (mid survival: EV= 11±1.05d, siAkt= 59±3.65d; p<0.0001), as well as they regained weight (initial= 33±1.4; EV 10d= 26±1.4; siAkt 10d= 33±1.4, p<0.05). To assess the redox influence on Akt1 phosphorylation, tumors were transfected with siTrx1 and 2, and it was observed a deficient P-Akt1 Ser473 build up in mitochondria in detriment of the translocation to nucleus. We conclude that silencing of Akt1 induces prolonged effects that abrogates proliferation and enhances apoptosis and markedly increases mice survival and weight gain; low redox status should contribute to tumor progression by favoring second phosphorylation of mitochondrial Akt1 in Thr308.