YAP and MRTF-A, transcriptional co-activators of RhoA-mediated gene expression, are critical for glioblastoma tumorigenicity
Authors: Daniel Ryback
Jorge A Benitez
Olivia M Yu
Anjana Rao
Benjamin Delatte
Jason Greenbaum
Joan Heller Brown
Olga Meiri Chaim
Kun-Liang Guan
Steven W Plouffe
Andrea Klein
Jeff Smith
Shigeki Miyamoto
Frank B Furnari
Journal: Oncogene (2018)
Discipline: MOLECULAR BIOLOGY & GENETICS
Keywords: YAP; MRTF-A; GPCRs; RhoA; glioblastoma cells
Affiliations: Department of Pharmacology, University of California, La Jolla, San Diego, CA, USA., Biomedical Sciences Graduate Program, University of California, La Jolla, San Diego, CA, USA., Ludwig Institute for Cancer Research, San Diego Branch, La Jolla, San Diego, CA, USA., Division of Signaling and Gene Expression, La Jolla Institute for Allergy and Immunology, La Jolla, CA, USA., Moores Cancer Center, University of California at San Diego, La Jolla, San Diego, CA, USA., Department of Pathology, School of Medicine, University of California, La Jolla, San Diego, CA, USA., Department of Cell Biology, Federal University of Paraná, Curitiba, Brazil., Department of Pharmacology, University of California, La Jolla, San Diego, CA, USA. ., Moores Cancer Center, University of California at San Diego, La Jolla, San Diego, CA, USA. .

Abstract:  The role of YAP (Yes-associated protein 1) and MRTF-A (myocardin-related transcription factor A), two transcriptional co-activators regulated downstream of GPCRs (G protein-coupled receptors) and RhoA, in the growth of glioblastoma cells and in vivo glioblastoma multiforme (GBM) tumor development was explored using human glioblastoma cell lines and tumor-initiating cells derived from patient-derived xenografts (PDX). Knockdown of these co-activators in GSC-23 PDX cells using short hairpin RNA significantly attenuated in vitro self-renewal capability assessed by limiting dilution, oncogene expression, and neurosphere formation. Orthotopic xenografts of the MRTF-A and YAP knockdown PDX cells formed significantly smaller tumors and were of lower morbidity than wild-type cells. In vitro studies used PDX and 1321N1 glioblastoma cells to examine functional responses to sphingosine 1-phosphate (S1P), a GPCR agonist that activates RhoA signaling, demonstrated that YAP signaling was required for cell migration and invasion, whereas MRTF-A was required for cell adhesion; both YAP and MRTF-A were required for proliferation. Gene expression analysis by RNA-sequencing of S1P-treated MRTF-A or YAP knockout cells identified 44 genes that were induced through RhoA and highly dependent on YAP, MRTF-A, or both. Knockdown of F3 (tissue factor (TF)), a target gene regulated selectively through YAP, blocked cell invasion and migration, whereas knockdown of HBEGF (heparin-binding epidermal growth factor-like growth factor), a gene selectively induced through MRTF-A, prevented cell adhesion in response to S1P. Proliferation was sensitive to knockdown of target genes regulated through either or both YAP and MRTF-A. Expression of TF and HBEGF was also selectively decreased in tumors from PDX cells lacking YAP or MRTF-A, indicating that these transcriptional pathways are regulated in preclinical GBM models and suggesting that their activation through GPCRs and RhoA contributes to growth and maintenance of human GBM. 

Retracted: No

PubPeer comments:
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