Genes & Cancer

EWS-FLI-1 creates a cell surface microenvironment conducive to IGF signaling by inducing pappalysin-1

Panneerselvam Jayabal1, Peter J. Houghton1,2,3 and Yuzuru Shiio1,2,4

1 Greehey Children’s Cancer Research Institute, The University of Texas Health Science Center, San Antonio, Texas, USA

2 Cancer Therapy and Research Center, The University of Texas Health Science Center, San Antonio, Texas, USA

3 Department of Molecular Medicine, The University of Texas Health Science Center, San Antonio, Texas, USA

4 Department of Biochemistry, The University of Texas Health Science Center, San Antonio, Texas, USA

Correspondence:

Yuzuru Shiio, email:

Keywords: Ewing sarcoma, EWS-FLI-1, IGFBP, IGF signaling, pappalysin-1

Received: September 04, 2017 Accepted: December 03, 2017 Published: December 15, 2017

Abstract

Ewing sarcoma is an aggressive cancer of bone and soft tissue in children with poor prognosis. It is characterized by the chromosomal translocation between EWS and an Ets family transcription factor, most commonly FLI-1. EWS-FLI-1 fusion accounts for 85% of Ewing sarcoma cases. EWS-FLI-1 regulates the expression of a number of genes important for sarcomagenesis, can transform NIH3T3 and C3H10T1/2 cells, and is necessary for proliferation and tumorigenicity of Ewing sarcoma cells, suggesting that EWS-FLI-1 is the causative oncoprotein.

Here we report that EWS-FLI-1 induces the expression of pappalysin-1 (PAPPA), a cell surface protease that degrades IGF binding proteins (IGFBPs) and increases the bioavailability of IGF. EWS-FLI-1 binds to the pappalysin-1 gene promoter and stimulates the expression of pappalysin-1, leading to degradation of IGFBPs and enhanced IGF signaling. Silencing of pappalysin-1 strongly inhibited anchorage-dependent and anchorage-independent growth as well as xenograft tumorigenicity of Ewing sarcoma cells. These results suggest that EWS-FLI-1 creates a cell surface microenvironment conducive to IGF signaling by inducing pappalysin-1, which emerged as a novel target to inhibit IGF signaling in Ewing sarcoma.


PII: 159