基底样乳腺癌（BBC）和恶性胶质母细胞瘤（GBM）是与差预后相关的侵袭性肿瘤。BBC和GBM具有干细胞样基因表达特征，这部分是由于Forkhead Box O（FOXO）转录因子的作用。为了进一步了解FOXO1在BBC中的影响，我们使用AS1842856处理BT549细胞，并进行了RNA测序。AS1842856结合未磷酸化的FOXO1，并抑制其直接结合DNA的能力。基因集富集分析（GSEA）表明，一组WNT信号通路靶基因，在AS1842856处理后表达显著上调，其中包括淋巴增强子结合因子1（LEF1）和转录因子7（TCF7）。这些同样的基因在GBM细胞系U87MG、LN18、LN229、A172和DBTRG处理AS1842856后也得到上调。相反，随后的RNA干扰（RNAi）靶向FOXO1导致BT549和U87MG细胞中LEF1和TCF7基因表达降低。与RNAi实验一致，CRISPR Cas9介导的FOXO1缺失降低了U87MG细胞中经典WNT基因LEF1和TCF7的表达。DNA结合缺乏FOXO1-H215R的外源表达能够恢复FOXO1缺失突变株中TCF7基因表达的丧失。因此，FOXO1以DNA结合非依赖的方式诱导TCF7基因表达，类似于其他已发表的FOXO1激活基因，如TCF4和bHLH转录因子1（HES1）。我们的研究证明，在进行的BBC和GBM细胞中，FOXO1促进了经典WNT基因的表达，类似于果蝇、T细胞发育和小鼠急性髓系白血病（AML）模型中的结果。本文受版权保护，所有权利均保留。

Basal-like breast cancer (BBC) and glioblastoma multiforme (GBM) are aggressive cancers associated with poor prognosis. BBC and GBM have stem-cell-like gene expression signatures, which are in part driven by forkhead box O (FOXO) transcription factors. To gain further insight into the impact of FOXO1 in BBC, we treated BT549 cells with AS1842856 and performed RNA sequencing. AS1842856 binds to unphosphorylated FOXO1 and inhibits its ability to directly bind to DNA. Gene Set Enrichment Analysis (GSEA) indicated that a set of WNT pathway target genes, including lymphoid enhancer-binding factor 1 (LEF1) and transcription factor 7 (TCF7), were robustly induced after AS1842856 treatment. These same genes were also induced in GBM cell lines U87MG, LN18, LN229, A172 and DBTRG upon AS1842856 treatment. In contrast, follow-up RNA interference (RNAi) targeting of FOXO1 led to reduced LEF1 and TCF7 gene expression in BT549 and U87MG cells. In agreement with RNAi experiments, CRISPR Cas9-mediated FOXO1 disruption reduced the expression of canonical WNT genes LEF1 and TCF7 in U87MG cells. The loss of TCF7 gene expression in FOXO1 disruption mutants was restored by exogenous expression of the DNA-binding-deficient FOXO1-H215R. Therefore, FOXO1 induces TCF7 in a DNA-binding-independent manner, similar to other published FOXO1-activated genes such as TCF4 and hes family bHLH transcription factor 1 (HES1). Our work demonstrates that FOXO1 promotes canonical WNT gene expression in examined BBC and GBM cells, similar to results found in Drosophila melanogaster, T-cell development and murine acute myeloid leukemia (AML) models.This article is protected by copyright. All rights reserved.