Thioredoxin facilitates hepatocellular carcinoma stemness and metastasis by increasing BACH1 stability to activate the AKT/mTOR pathway

Thioredoxin (TXN) is essential for preserving balance and controlling the intracellular redox state. Most studies have focused on the function of TXN in redox reactions, which is critical for tumor progression. Here, we showed that TXN promotes hepatocellular carcinoma (HCC) stemness properties in a non-redox-dependent manner, which has rarely been reported in previous studies. TXN exhibited upregulated expression in human HCC specimens, which was associated with a poor prognosis. Functional studies showed that TXN promoted HCC stemness properties and facilitated HCC metastasis both in vitro and in vivo. Mechanistically, TXN promoted the stemness of HCC cells by interacting with BTB and CNC homology 1 (BACH1) and stabilized BACH1 expression by inhibiting its ubiquitination. BACH1 was positively correlated with TXN expression and was significantly upregulated in HCC. In addition, BACH1 promotes HCC stemness by activating the AKT/mammalian target of rapamycin (mTOR) pathway. Furthermore, we found that the specific inhibition of TXN in combination with lenvatinib in mice significantly improved the treatment of metastatic HCC. In summary, our data demonstrate that TXN plays a crucial role in HCC stemness and BACH1 plays an integral part in regulating this process by activating the AKT/mTOR pathway. Thus, TXN is a promising target for metastatic HCC therapy.