Exploring the oncogenic roles of T-box transcription factor TBX2 and its potential as a therapeutic target.

Abstract

During embryonic development, the T-box transcription factor TBX2 regulates key processes such as cell fate decisions, migration and tissue morphogenesis, and mutations that lead to reduced TBX2 levels result in developmental abnormalities including congenital heart and skeletal defects. TBX2, on the other hand, is overexpressed in a plethora of cancers where it functions as a powerful oncogene contributing to processes ranging from the bypass of senescence and cell death pathways to the promotion of cell proliferation, and epithelial-to-mesenchymal transition to drive invasion and metastasis. Additionally, TBX2 has been implicated in conferring resistance to anti-cancer drugs resulting in poor therapeutic outcomes. To exert its oncogenic functions, TBX2 transcriptionally represses key tumour suppressor genes involved in controlling cell proliferation and epithelial-to-mesenchymal transition such as p21Cip1, p14/p19ARF PTEN, NDRG1, CST6 and E-cadherin. This repression has been shown to involve complex mechanisms by which TBX2 co-opts transcription factors and recruits co-repression complexes to the promoters of these tumour suppressor genes. While limited information is available on how TBX2 is regulated in cancers, there is evidence that the levels and oncogenic functions of TBX2 are induced by developmental signalling pathways that are hijacked by cancer cells such as the Wnt/β-catenin and PI3K/AKT pathways. Understanding the complex molecular networks that TBX2 is involved in to exert its oncogenic functions is important because it may reveal potential therapeutic strategies for targeting TBX2 in TBX2-dependent cancers. This minireview discusses TBX2's involvement in cancer signalling, its regulatory partners, and its impact on cancer progression and resistance to therapy.