IGF 1 MODULATES ZEB1 STABILITY DURING EPITHELIAL MESENCHYMAL TRANSITION (EMT)

LLORENS, M. CANDELARIA; VAGLIENTI, MARIA V.; CABANILLAS, ANA M.

Córdoba

Congreso; LII Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2016

SAIB

ZEB1 is a transcription factor (TF) involved in EMT and oncogenesis. Previously we showed that an N-term fragment of ZEB1(NZEB1) was able to induce EMT by itself in mouse epithelial cells NMuMG. We intend to determine the mechanisms involved in regulating NZEB1 during EMT. NMuMG-NZEB1 cells were treated with specific inhibitors and activators of signaling pathways for 48h. Immunoblots against NZEB1, E-cadherin and α-tubulin (loading control) and the activity of pathways were assayed. None of the reagents modified the effect of NZEB1 on E-Cadherin expression. However, incubation with 5µM NVP (IGF1R inhibitor) for 48 hreduced NZEB1 expression (P<0.05). Confocal microscopy and IF of tested cells also revealed a changed pattern of F-actin filaments to a more epithelial-like distribution than controls. Coincidently, invasive and migration assays showed a strong reduction in their values after NVP treatment compared to controls (P<0.001). The protein stability of NZEB1 was also assessed in NMuMG-NZEB1cells treated with NVP + 5µM MG132 for 48 h. Immunoblots showed that MG132 reverted NVP effect and increased NZEB1 expression suggesting that NVP reduces ZEB1 stability by proteasome degradation. Coincidently, IGF1 treatment for 48h, increased ZEB1 stability. The results strongly suggest that IGF1R pathway could regulate ZEB1 expression and therefore EMT by regulating the TF stability.