TBX21 attenuates colorectal cancer progression via an ARHGAP29/RSK/GSK3β dependent manner.

Purpose: Previous studies have shown that TBX21 (T-Box Transcription Factor 21) plays a vital role in coordinating multiple aspects of the immune response especially type 1 immune response as well as tumor progression. However, the function of TBX21 in colorectal cancer (CRC) remains unclear.

Methods: IHC to investigate TBX21 expression in CRC tissues. Cell proliferation and apoptosis assays to validate TBX21 function in vitro and in vivo. RNA-seq assay to explore target genes of TBX21. Human phospho-kinase array assay to explore down-stream signaling of TBX21.

Results: We disclosed that the expression of TBX21 was marked decreased in CRC versus normal tissue, and negatively correlated with CRC TNM stages. Surprisingly, we found that the CRC and normal cell lines show no TBX21 expression levels. Ectopic expression of TBX21 inhibited cell proliferation and promoted cell apoptosis in vitro. Moreover, RNA-sequence data first time showed that ARHGAP29 acts as the target gene of TBX21 to mediate down-stream signaling activation. Human phospho-kinase array data first time displayed that ectopic expression of TBX21 reduced kinase RSK and GSK3β activation. In contrast, knocked down the expression of TBX21 or ARHGAP29 alternatively abolished TBX21 mediated cell proliferation suppression, cell apoptosis enhancement and RSK/GSK3β activation. In addition, xenograft model studies demonstrated that TBX21 inhibits colorectal tumor progression via ARHGAP29/ RSK/ GSK3β signaling in vivo.

Conclusions: In summary, the aforementioned findings suggest a model of TBX21 in suppressing CRC progression. This may provide a promising target for CRC therapy.