Nephronectin mediates p38 MAPK-induced cell viability via its integrin-binding enhancer motif.

Jimita Toraskar,Konika Chawla,Gunbjørg Svineng,Tonje S Steigedal,Synnøve N Magnussen

doi:10.1002/2211-5463.12544

Abstract

Nephronectin (NPNT) is an extracellular matrix (ECM) protein involved in kidney development. We recently reported intracellular NPNT as a potential prognostic marker in breast cancer and that NPNT promotes metastasis in an integrin‐dependent manner. Here, we used reverse‐phase protein array (RPPA) to analyze NPNT‐triggered intracellular signaling in the 66cl4 mouse breast cancer cell line. The results showed that the integrin‐binding enhancer motif is important for the cellular effects upon NPNT interaction with its receptors, including phosphorylation of p38 mitogen‐activated protein kinase (MAPK). Furthermore, analysis using prediction tools suggests involvement of NPNT in promoting cell viability. In conclusion, our results indicate that NPNT, via its integrin‐binding motifs, promotes cell viability through phosphorylation of p38 MAPK.

Highlights

Nephronectin (NPNT) is an extracellular matrix (ECM) protein involved in kidney development
NPNT is mostly documented to be an extracellular protein [6,17,18], we have recently shown that NPNT is localized intracellularly in the cytoplasm and packed in vesicles/granules in breast cancer tissues and in exosomes isolated from cell lines [14]
Seeding equal numbers of 66cl4-empty vector cells (EV) cells on recombinant mouse NPNT (rmNPNT)-coated plates and uncoated plates showed that presence of rmNPNT increased the proportion of cells that attached and spread out compared to the uncoated plates where a large number of cells still remained rounded at 24 h (Fig. 1C)

Summary

Introduction

Nephronectin (NPNT) is an extracellular matrix (ECM) protein involved in kidney development. We used reverse-phase protein array (RPPA) to analyze NPNT-triggered intracellular signaling in the 66cl4 mouse breast cancer cell line.

Results

Conclusion