AUTHOR=Riffo Elizabeth , Palma Mario , Hepp Matías I. , Benítez-Riquelme Diego , Torres Vicente A. , Castro Ariel F. , Pincheira Roxana 

TITLE=The Sall2 transcription factor promotes cell migration regulating focal adhesion turnover and integrin β1 expression

JOURNAL=Frontiers in Cell and Developmental Biology

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/cell-and-developmental-biology/articles/10.3389/fcell.2022.1031262

DOI=10.3389/fcell.2022.1031262

ISSN=2296-634X

ABSTRACT=<p>SALL2/Sall2 is a transcription factor associated with development, neuronal differentiation, and cancer. Interestingly, <italic>SALL2/Sall2</italic> deficiency leads to failure of the optic fissure closure and neurite outgrowth, suggesting a positive role for SALL2/Sall2 in cell migration. However, in some cancer cells, <italic>SALL2</italic> deficiency is associated with increased cell migration. To further investigate the role of Sall2 in the cell migration process, we used immortalized <italic>Sall2</italic> knockout (<italic>Sall2</italic><sup><italic>−/−</italic></sup>) and <italic>Sall2</italic> wild-type (<italic>Sall2</italic><sup><italic>+/+</italic></sup>) mouse embryonic fibroblasts (iMEFs). Our results indicated that Sall2 positively regulates cell migration, promoting cell detachment and focal adhesions turnover. <italic>Sall2</italic> deficiency decreased cell motility and altered focal adhesion dynamics. Accordingly, restoring Sall2 expression in the <italic>Sall2</italic><sup><italic>−/−</italic></sup> iMEFs by using a doxycycline-inducible Tet-On system recovered cell migratory capabilities and focal adhesion dynamics. In addition, Sall2 promoted the autophosphorylation of Focal Adhesion Kinase (FAK) at Y397 and increased integrin β1 mRNA and its protein expression at the cell surface. We demonstrated that SALL2 increases <italic>ITGB1</italic> promoter activity and binds to conserved SALL2-binding sites at the proximal region of the <italic>ITGB1</italic> promoter, validated by ChIP experiments. Furthermore, the overexpression of integrin β1 or its blockade generates a cell migration phenotype similar to that of <italic>Sall2</italic><sup><italic>+/+</italic></sup> or <italic>Sall2</italic><sup><italic>−/−</italic></sup> cells, respectively. Altogether, our data showed that Sall2 promotes cell migration by modulating focal adhesion dynamics, and this phenotype is associated with SALL2/Sall2-transcriptional regulation of integrin β1 expression and FAK autophosphorylation. Since deregulation of cell migration promotes congenital abnormalities, tumor formation, and spread to other tissues, our findings suggest that the SALL2/Sall2-integrin β1 axis could be relevant for those processes.</p>