SLX4 and XPF are involved in cell migration and EMT in a cell-specific manner.

SLX4 and XPF are two proteins involved in DNA repair, but very little is known about their potential roles in other processes of cancer cell biology. We developed original cell models with CRISPR-Cas9-mediated knock-out of SLX4 and/or XPF using five different cell lines (A549, NCI-H1703, COLO-357, HT-29 and HEK-293 T), and performed characterization with cell biology experiments including migration assays, drug sensitivity testing, cell proliferation assessment and Western blots for relevant proteins. Results showed decreased migration of all models in HT-29 cells, of XPF-deficient COLO-357 cells and of SLX4-deficient HEK-293 T cells. Modified cell models had overall increased sensitivity to cisplatin and mitomycine C, and some models showed an increased frequency of double-stranded DNA damages. One NCI-H1703 cell model showed major karyotypic modifications, and epithelial to mesenchymal transition (EMT)-related proteins were modified in several models. Finally, knocking out one or both proteins in A549 cells had not the same impact on in vivo growth in mice. These original cell models allowed us to identify new and DNA repair-unrelated cellular roles of SLX4 and XPF in cancer cell biology. Our results should be considered within work on Nucleotide Excision Repair (NER) inhibition targeting SLX, XPF or other related proteins.