Classification of a frameshift/extended and a stop mutation in WT1 as gain of function mutations which activate cell cycle genes and promote Wilms tumor cell proliferation

ABSTRACT: The Wilms tumor 1 (WT1) gene encodes a zinc finger transcription factor important for normal kidney development. WT1 is a suppressor for Wilms tumor development and an oncogene for diverse malignant tumors. We recently established cell lines from primary Wilms tumors and identified the corresponding WT1 mutations (see GSE18058). To investigate the function of mutant WT1 proteins we performed WT1 knockdown experiments in primary Wilms tumor cell lines with a frameshift/extension (p.V432fsX87 = Wilms3) and a stop mutation (p.P362X = Wilms2) of WT1, followed by genome wide gene expression analysis. A detailed analysis of these gene expression data using MetaCore enabled us to classify the WT1 mutations as gain of function mutations. The mutant WT1Wilms2 and WT1Wilms3 proteins acquired an ability to modulate the expression of a highly significant number of genes from the G2/M phase of the cell cycle, and WT1 knockdown experiments showed that they are required for Wilms tumor cell proliferation. Data from the literature show that p53 negatively regulates the activity of a large number of these genes which are also part of a core proliferation cluster in diverse human cancers. Our data strongly suggest that mutant WT1 proteins facilitate expression of these cell cycle genes by antagonizing transcriptional repression mediated by p53. In light of this it is important to note that mutant WT1 has an ability to physically interact with the tumor suppressor p53. Together the findings show for the first time, that mutant WT1 proteins have a gain of function and act as oncogenes for Wilms tumor development by regulating Wilms tumor cell proliferation.

ORGANISM(S): Homo sapiens

PROVIDER: GSE54635 | GEO | 2014/05/12

SECONDARY ACCESSION(S): PRJNA237236

REPOSITORIES: GEO