Faculty Collaboration Database

Glycogen synthase kinase-3 inhibitor AR-A014418 suppresses pancreatic cancer cell growth via inhibition of GSK-3-mediated Notch1 expression. HPB (Oxford) 2015 Sep;17(9):770-6

Date

07/07/2015

Pubmed ID

26147011

Pubmed Central ID

PMC4557650

DOI

10.1111/hpb.12442

Scopus ID

2-s2.0-84939464651 (requires institutional sign-in at Scopus site)   37 Citations

Abstract

BACKGROUND: Glycogen synthase kinase-3 (GSK-3) can act as either a tumour promoter or suppressor by its inactivation depending on the cell type. There are conflicting reports on the roles of GSK-3 isoforms and their interaction with Notch1 in pancreatic cancer. It was hypothesized that GSK-3α stabilized Notch1 in pancreatic cancer cells thereby promoting cellular proliferation.

METHODS: The pancreatic cancer cell lines MiaPaCa2, PANC-1 and BxPC-3, were treated with 0-20 μM of AR-A014418 (AR), a known GSK-3 inhibitor. Cell viability was determined by the MTT assay and Live-Cell Imaging. The levels of Notch pathway members (Notch1, HES-1, survivin and cyclinD1), phosphorylated GSK-3 isoforms, and apoptotic markers were determined by Western blot. Immunoprecipitation was performed to identify the binding of GSK-3 specific isoform to Notch1.

RESULTS: AR-A014418 treatment had a significant dose-dependent growth reduction (P < 0.001) in pancreatic cancer cells compared with the control and the cytotoxic effect is as a result of apoptosis. Importantly, a reduction in GSK-3 phosphorylation lead to a reduction in Notch pathway members. Overexpression of active Notch1 in AR-A014418-treated cells resulted in the negation of growth suppression. Immunoprecipitation analysis revealed that GSK-3α binds to Notch1.

CONCLUSIONS: This study demonstrates for the first time that the growth suppressive effect of AR-A014418 on pancreatic cancer cells is mainly mediated by a reduction in phosphorylation of GSK-3α with concomitant Notch1 reduction. GSK-3α appears to stabilize Notch1 by binding and may represent a target for therapeutic development. Furthermore, downregulation of GSK-3 and Notch1 may be a viable strategy for possible chemosensitization of pancreatic cancer cells to standard therapeutics.

Author List

Kunnimalaiyaan S, Gamblin TC, Kunnimalaiyaan M

MESH terms used to index this publication - Major topics in bold

Apoptosis
Blotting, Western
Cell Line, Tumor
Cell Proliferation
Cell Survival
Glycogen Synthase Kinase 3
Humans
Immunoprecipitation
Pancreas
Pancreatic Neoplasms
Receptor, Notch1
Thiazoles
Urea