The GSK3β inhibitor BIS I reverts YAP-dependent EMT signature in PDAC cell lines by decreasing SMADs expression level

Abstract

The Yes-associated protein, YAP, is a transcriptional co-activator, mediating the Epithelial to Mesenchymal Transition program in pancreatic ductal adenocarcinoma (PDAC). With the aim to identify compounds that can specifically modulate YAP functionality in PDAC cell lines, we performed a small scale, drug-based screening experiment using YAP cell localization as the read-out. We identified erlotinib as an inducer of YAP cytoplasmic localization, an inhibitor of the TEA luciferase reporter system and the expression of the bona fide YAP target gene, Connective Tissue Growth Factor CTGF. On the other hand, BIS I, an inhibitor of PKCδ and GSK3β, caused YAP accumulation into the nucleus. Activation of β-catenin reporter and interfering experiments show that inhibition of the PKCδ/GSK3β pathway triggers YAP nuclear accumulation inducing YAP/TEAD transcriptional response. Inhibition of GSK3β by BIS I reduced the expression levels of SMADs protein and reduced YAP contribution to EMT. Notably, BIS I reduced proliferation, migration and clonogenicity of PDAC cells in vitro, phenocopying YAP genetic down-regulation. As shown by chromatin immunoprecipitation experiments and YAP over-expressing rescue experiments, BIS I reverted YAP-dependent EMT program by modulating the expression of the YAP target genes E-cadherin, vimentin, CTGF and of the newly identified target, CD133. In conclusion, we identified two different molecules, erlotinib and BIS I, modulating YAP functionality although via different mechanisms of action, with the second one specifically inhibiting the YAP-dependent EMT program in PDAC cell lines.

The roles of ING5 expression in ovarian carcinogenesis and subsequent progression: a target of gene therapy

“…Zhao et al [ 17 ] found that ING5 significantly inhibited the phosphorylation of PI3K and Akt in breast cancer cells, leading to MET. In addition, EMT is positively associated with aberrant activation of Wnt or the PI3K/Akt pathway, which activates GSK-3β and stabilizes β-catenin [ 20 , 21 ]. We found that PI3K, Akt, and β-catenin were decreased in ING5 transfectants of ovarian cancer cells.…”

EMT induced by loss of LKB1 promotes migration and invasion of liver cancer cells through ZEB1‑induced YAP signaling

“…The Yes-associated protein (YAP) is a transcriptional factor of the Hippo signaling pathway ( 11 ). A number of studies have supported a critical role for YAP in different types of cancer, including breast and lung cancer and pancreatic ductal adenocarcinoma (PDAC) ( 12 , 13 ). YAP has been demonstrated to be an essential promoter of the mutant KRAS oncogenic program, specifically inducing the expression of secreted factors such as CTGF and CYR61, and interacting with FOS, a proto-oncogene, to regulate the expression of EMT-associated genes such as E-cadherin, SLUG, SNAIL and Vimentin ( 13 , 14 ).…”

The Hippo Signaling Pathway in Pancreatic Cancer

“…Of the evaluated treatments in pancreatic cancer to date, only verteporfin (33,34) has a direct effect upon Hippo signaling. Erlotinib (35), BIS 1 (35) and LY3009120 (33) indirectly affect YAP and TAZ signaling. The mechanism of action is not fully clarified for several natural substances, such as curcumin (36), resveratrol (37), Stiehopus japonieus acidic mucopolysaccharide (38) and pseudolaric acid B (39).…”