TGM3 functions as a tumor suppressor by repressing epithelial-to-mesenchymal transition and the PI3K/AKT signaling pathway in colorectal cancer

The dysregulation of transcription factors contributes to the unlimited proliferation of cancer cells. Transglutaminase 3 (TGM3) has been demonstrated to play a crucial role in physiology and pathology. However, the potential role of TGM3 in colorectal cancer (CRC) remains unknown. In the present study, reverse transcription-quantitative PCR and immunohistochemistry were utilized to analyze the expression of TGM3 in CRC and adjacent normal tissues. LoVo and HCT116 cell lines were then selected to further investigate the function of TGM3 in the proliferation, invasion and metastasis of CRC both in vitro and in vivo. Finally, western blotting was performed to investigate the molecular mechanisms underlying the effects of TGM3 in CRC. The expression level of TGM3 was significantly downregulated in CRC tissues, and was associated with tumor invasion, metastasis and patient prognosis. Following TGM3 inhibition and overexpression in CRC cells, it was revealed that TGM3 suppressed cell proliferation, potentially via the promotion of apoptosis and cell cycle regulation. Furthermore, TGM3 also inhibited invasion and metastasis. Finally, it was observed that TGM3 inhibited epithelial-to-mesenchymal transition and activated phosphorylated AKT serine/threonine kinase in CRC cells. The results from the present study revealed that TGM3 is a tumor suppressor in the progression of CRC, and may be used as a novel target for CRC treatment.