Inhibition of WNT-CTNNB1 signaling upregulates SQSTM1 and sensitizes glioblastoma cells to autophagy blockers. Issue 4 (3rd April 2018)

• Record Type: Journal Article
• Authors: Nàger, Mireia; Sallán, Marta C.; Visa, Anna; Pushparaj, Charumathi; Santacana, Maria; Macià, Anna; Yeramian, Andrée; Cantí, Carles; Herreros, Judit
• Is Part Of: Autophagy. Volume 14:Issue 4(2018)
• Page Start: 619
• Page End: 636
• Publication Date: 2018-04-03
• Subjects: Autophagy -- CTNNB1 -- glioblastoma -- SQSTM1 -- TCF -- TFEB -- WNT; Autophagic vacuoles -- Periodicals; Apoptosis -- Periodicals; Cell death -- Periodicals; Lysosomes -- Periodicals; Degeneration (Pathology) -- Periodicals; Autophagy -- Periodicals; Cell Death -- Periodicals; Lysosomes -- Periodicals; Periodicals; 571.936
• DOI: 10.1080/15548627.2017.1423439
• Languages: English
• ISSNs: 1554-8627

Abstract

ABSTRACT: WNT-CTNN1B signaling promotes cancer cell proliferation and stemness. Furthermore, recent evidence indicates that macroautophagy/autophagy regulates WNT signaling. Here we investigated the impact of inhibiting WNT signaling on autophagy in glioblastoma (GBM), a devastating brain tumor. Inhibiting TCF, or silencing TCF4 or CTNNB1/β-catenin upregulated SQSTM1/p62 in GBM at transcriptional and protein levels and, in turn, autophagy. DKK1/Dickkopf1, a canonical WNT receptor antagonist, also induced autophagic flux. Importantly, TCF inhibition regulated autophagy through MTOR inhibition and dephosphorylation, and nuclear translocation of TFEB, a master regulator of lysosomal biogenesis and autophagy. TCF inhibition or silencing additionally affected GBM cell proliferation and migration. Autophagy induction followed by its blockade can promote cancer cell death. In agreement with this notion, halting both TCF-CTNNB1 and autophagy pathways decreased cell viability and induced apoptosis of GBM cells through a SQSTM1-dependent mechanism involving CASP8 (caspase 8). In vivo experiments further underline the therapeutic potential of such dual targeting in GBM.