The HNRNPA2B1-MST1R-Akt axis contributes to epithelial-to-mesenchymal transition in head and neck cancer

Lab Invest. 2020 Dec;100(12):1589-1601. doi: 10.1038/s41374-020-0466-8. Epub 2020 Jul 15.

Abstract

The deregulation of splicing factors and alternative splicing are increasingly viewed as major contributory factors in tumorigenesis. In this study, we report overexpression of a key splicing factor, heterogeneous nuclear ribonucleoprotein A2B1 (HNRNPA2B1), and thereby misregulation of alternative splicing, which is associated with the poor prognosis of head and neck cancer (HNC). The role of HNRNPA2B1 in HNC tumorigenesis via deregulation of alternative splicing is not well understood. Here, we found that the CRISPR/Cas9-mediated knockout of HNRNPA2B1 results in inhibition of HNC cells growth via the misregulation of alternative splicing of MST1R, WWOX, and CFLAR. We investigated the mechanism of HNRNPA2B1-mediated HNC cells growth and found that HNRNPA2B1 plays an important role in the alternative splicing of a proto-oncogene, macrophage stimulating 1 receptor (MST1R), which encodes for the recepteur d'origine nantais (RON), a receptor tyrosine kinase. Our results indicate that HNRNPA2B1 mediates the exclusion of cassette exon 11 from MST1R, resulting in the generation of RON∆165 isoform, which was found to be associated with the activation of Akt/PKB signaling in HNC cells. Using the MST1R-minigene model, we validated the role of HNRNPA2B1 in the generation of RON∆165 isoform. The depletion of HNRNPA2B1 results in the inclusion of exon 11, thereby reduction of RON∆165 isoform. The decrease of RON∆165 isoform causes inhibition of Akt/PKB signaling, which results in the upregulation of E-cadherin and downregulation of vimentin leading to the reduced epithelial-to-mesenchymal transition. The overexpression of HNRNPA2B1 in HNRNPA2B1 knockout cells rescues the expression of the RON∆165 isoform and leads to activation of Akt/PKB signaling and induces epithelial-to-mesenchymal transition in HNC cells. In summary, our study identifies HNRNPA2B1 as a putative oncogene in HNC that promotes Akt/PKB signaling via upregulation of RON∆165 isoform and promotes epithelial to mesenchymal transition in head and neck cancer cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line, Tumor
  • Epithelial-Mesenchymal Transition / genetics*
  • Gene Expression Regulation, Neoplastic
  • Head and Neck Neoplasms* / genetics
  • Head and Neck Neoplasms* / metabolism
  • Head and Neck Neoplasms* / mortality
  • Head and Neck Neoplasms* / pathology
  • Heterogeneous-Nuclear Ribonucleoprotein Group A-B / genetics
  • Heterogeneous-Nuclear Ribonucleoprotein Group A-B / metabolism*
  • Humans
  • Proto-Oncogene Mas
  • Proto-Oncogene Proteins c-akt / genetics
  • Proto-Oncogene Proteins c-akt / metabolism*
  • Receptor Protein-Tyrosine Kinases / genetics
  • Receptor Protein-Tyrosine Kinases / metabolism*

Substances

  • Heterogeneous-Nuclear Ribonucleoprotein Group A-B
  • MAS1 protein, human
  • Proto-Oncogene Mas
  • RON protein
  • Receptor Protein-Tyrosine Kinases
  • Proto-Oncogene Proteins c-akt