The Impact of High-mobility Group Box Mutation of T-cell Factor 4 on Its Genomic Binding Pattern in Non–small Cell Lung Cancer

Abstract

T-cell factor 4 (TCF-4) is determined to play a crucial role in Wnt/β-catenin signaling pathway activation. The mutations and alternative splice isoforms of TCF-4 can cause cancers and other diseases. The high-mobility group (HMG) box domain of TCF-4 contributes to interacting with DNA motif for transcriptional regulation. However, the impact of the mutations within HMG box of TCF-4 on the genomic binding pattern is poorly investigated. Herein, we generated non–small cell lung cancer (NSCLC) cell line A549 with stably overexpressed TCF-4 with HMG box hot spot mutation (10th exon partial deletion), and conducted TCF-4 and β-catenin chromatin immunoprecipitation sequence to explore the differential genomic binding patterns. Our results revealed that TCF-4 lost 19365 but gained 1724 peaks, and β-catenin lost 4035 but gained 5287 peaks upon mutant TCF-4 compared with the wild type (log2FC > 1 or < -1, FDR<0.01). The transcriptional levels of the genes associated with these differential peaks such as H3F3C, KRT1, KRT14, MMp1, and MMP15 were all found to strongly change responding to TCF-4 binding (P < 0.05). Furthermore, A549 cells with TCF-4 mutation displayed a more compromising tumor characterization on cell proliferation and invasion. Our data determined the important role of TCF-4 in gene transcription controlling and provided the gain function evidence of TCF-4 caused by the TCF-4 mutation in NSCLC.

Evolutionary diversification of the canonical Wnt signaling effector TCF/LEF in chordates

“…The HMG box is the domain responsible for the binding to and recognition of Wnt response elements (WREs), so, changes in the coding sequences of the HMG box could alter this recognition as well as binding affinities. Recently, one study identified several mutations in the TCF7L2 HMG box that are associated with lung cancer (Su et al., 2020 ). One of these mutations is precisely the change from valine (V) to isoleucine (I) at HMG‐box position 22 that we have found to be a specific change conserved across the TCF7 subfamily (Figure 4b ).…”