p53 is a suppressor of the carcinoma-associated transcription factor FOXQ1

FOXQ1 transcription factors is highly induced in several types of carcinomas where it promotes tumour growth and metastasis, however, the molecular mechanisms leading to FOXQ1 deregulation in cancer are incompletely understood. Here, we used a CRISPR/Cas9-based genomic locus proteomics (GLoPro) to discover transcriptional regulators of FOXQ1 and identified the tumour suppressor p53 as a transcriptional repressor of FOXQ1 expression. ChIP-qPCR as well as complementary gain and loss-of-function assays in model cell lines indicated that p53 has multiple binding sites close to the transcription start site of the FOXQ1 promoter, and that it suppresses FOXQ1 expression in various cell types. Consistently, pharmacological activation of p53 using nutlin-3 or doxorubicin reduced FOXQ1 mRNA and protein levels in colorectal cancer cell lines harboring wild type p53. In conclusion, these results suggest that mutational loss-of-function of p53, a hallmark feature of many types of cancer, de-represses FOXQ1, which accelerates tumour progression.