TRIM21 promotes colorectal cancer development through regulating DNA replication by TCF3/MCM2/5 axis

Disrupting DNA replication has been employed for treating cancers. In the present study, we found that Tripartite motif containing 21 (TRIM21) was highly expressed in colorectal cancer (CRC) and could be valuable for predicting the prognosis of CRC patients. Further study demonstrated that TRIM21 positively regulated the expression of MCM2 and MCM5, DNA replication and proliferation of CRC cells both in vitro and in vivo. In addition, TRIM21 knockdown inhibited both replication initiation and velocity, and increased the chemosensitivity of CRC cells to 5-FU and SN-38. Our study also revealed that DNA replication inhibition following TRIM21 knockdown could not be restored by cell cycle checkpoint kinase inhibitors, but partially by Transcription Factor 3 (TCF3) knockdown. TCF3 directly suppressed MCM2 and MCM5 transcription, inhibiting DNA replication. In summary, TRIM21 could influence tumor development and chemosensitivity to replication inhibitors by regulating DNA replication through the TCF3/MCM2/5 axis, suggesting a promising potential for CRC in the clinic.