Wilms' tumor gene 1 regulates p63 and promotes cell proliferation in squamous cell carcinoma of the head and neck.

Xingru Li,Xiaolian Gu,Aihong Li,Sihan Wang,Karin Nylander,Emma Jernberg,Linda Boldrup,Sofia Ottosson

doi:10.1186/s12885-015-1356-0

Abstract

BackgroundWilms’ tumor gene 1 (WT1) can act as a suppressor or activator of tumourigenesis in different types of human malignancies. The role of WT1 in squamous cell carcinoma of the head and neck (SCCHN) is not clear. Overexpression of WT1 has been reported in SCCHN, suggesting a possible oncogenic role for WT1. In the present study we aimed at investigating the function of WT1 and its previously identified protein partners p63 and p53 in the SCCHN cell line FaDu.MethodsSilencing RNA (siRNA) technology was applied to knockdown of WT1, p63 and p53 in FaDu cells. Cell proliferation was detected using MTT assay. Chromatin immunoprecipitation (ChIP)/PCR analysis was performed to confirm the effect of WT1 on the p63 promoter. Protein co-immunoprecipitation (co-IP) was used to find protein interaction between WT1 and p53/p63. Microarray analysis was used to identify changes of gene expression in response to knockdown of either WT1 or p63. WT1 RNA level was detected using real-time quantitative PCR (RT-qPCR) in patients with SCCHN.ResultsWe found that WT1 and p63 promoted cell proliferation, while mutant p53 (R248L) possessed the ability to suppress cell proliferation. We reported a novel positive correlation between WT1 and p63 expression. Subsequently, p63 was identified as a WT1 target gene. Furthermore, expression of 18 genes involved in cell proliferation, cell cycle regulation and DNA replication was significantly altered by downregulation of WT1 and p63 expression. Several known WT1 and p63 target genes were affected by WT1 knockdown. Protein interaction was demonstrated between WT1 and p53 but not between WT1 and p63. Additionally, high WT1 mRNA levels were detected in SCCHN patient samples.ConclusionsOur findings suggest that WT1 and p63 act as oncogenes in SCCHN, affecting multiple genes involved in cancer cell growth.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-015-1356-0) contains supplementary material, which is available to authorized users.

Highlights

Wilms’ tumor gene 1 (WT1) can act as a suppressor or activator of tumourigenesis in different types of human malignancies
Our findings suggest that WT1 and p63 act as oncogenes in SCCHN, affecting multiple genes involved in cancer cell growth
Altered cell proliferation through knockdown of WT1, p63 and p53 To determine the effect of WT1, p63 and p53 on cell proliferation in FaDu cells in vitro, MTT assays were performed

Summary

Introduction

Wilms’ tumor gene 1 (WT1) can act as a suppressor or activator of tumourigenesis in different types of human malignancies. The role of WT1 in squamous cell carcinoma of the head and neck (SCCHN) is not clear. In the present study we aimed at investigating the function of WT1 and its previously identified protein partners p63 and p53 in the SCCHN cell line FaDu. Squamous cell carcinoma of the head and neck (SCCHN) is the sixth most common cancer and the most common tumor type in the head and neck region. Wilms’ tumor gene 1 (WT1) was first identified as a tumor suppressor gene in Wilms’ tumor, a childhood kidney neoplasm [8]; later findings demonstrated oncogenic properties in other malignancies including breast [9], lung [10,11], ovarian [12,13] and brain tissue [14]. The interaction has not been studied in any other cell types yet

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