Erratum: Thioredoxin 1 supports colorectal cancer cell survival and promotes migration and invasion under glucose deprivation through interaction with G6PD: Erratum.

[This corrects the article DOI: 10.7150/ijbs.71809.].

Inhibition of thioredoxin-1 enhances the toxicity of glycolysis inhibitor 2-deoxyglucose by downregulating SLC1A5 expression in colorectal cancer cells.

BACKGROUND: Targeting glycolysis in cancer is an attractive approach for therapeutic intervention. 2-Deoxyglucose (2DG) is a synthetic glucose analog that inhibits glycolysis. However, its efficacy is limited by the systemic toxicity at high doses. Understanding the mechanism of 2DG resistance is important for further use of this drug in cancer treatment. METHODS: The expression of thioredoxin-1 (Trx-1) in colorectal cancer (CRC) cells treated with 2DG was detected by Western blotting. The effect of Trx-1 on the cytotoxicity of 2DG in CRC cells was examined in vitro and in vivo. The molecular mechanism involved in Trx-1-mediated activation of the SLC1A5 gene promoter activity was elucidated using in vitro models. RESULTS: Inhibition glycolysis with 2DG increased the expression of Trx-1 in CRC cells. Overexpression of Trx-1 decreased the cytotoxicity of 2DG, whereas knockdown of Trx-1 by shRNA significantly increased the cytotoxicity of 2DG in CRC cells. The Trx-1 inhibitor PX-12 increased the cytotoxicity of 2DG on CRC cells both in vitro and in vivo. In addition, Trx-1 promoted SLC1A5 expression by increasing the promoter activity of the SLC1A5 gene by binding to SP1. We also found that the SLC1A5 expression was upregulated in CRC tissues, and inhibition of SLC1A5 significantly enhanced the inhibitory effect of 2DG on the growth of CRC cells in vitro and in vivo. Overexpression of SLC1A5 reduced the cytotoxicity of 2DG in combination with PX-12 treatment in CRC cells. CONCLUSION: Our results demonstrate a novel adaptive mechanism of glycolytic inhibition in which Trx-1 increases GSH levels by regulating SLC1A5 to rescue cytotoxicity induced by 2DG in CRC cells. Inhibition of glycolysis in combination with inhibition of Trx-1 or SLC1A5 may be a promising strategy for the treatment of CRC.

Nuclear translocation of thioredoxin-1 promotes colorectal cancer development via modulation of the IL-6/STAT3 signaling axis through interaction with STAT3.

Background: Thioredoxin 1 (Trx-1) is a small redox protein predominantly localized in the cytoplasm. Its expression is increased in several cancers, including colorectal cancer (CRC). However, the function of Trx-1 translocation to the nucleus in cancer is not clear. In this study, we investigated the role of Trx-1 nuclear translocation in development of CRC. Methods: Expression of Trx-1 and STAT3 was analyzed by Western blot and immunofluorescence. Endogenous interaction of Trx-1, STAT3, and karyopherin α1 in CRC cells was analyzed by co-immunoprecipitation. Trx-1 and pSTAT3 nuclear staining in human CRC tissues was analyzed by immunohistochemistry. A mouse model of AOM/DSS induced colitis-associated cancer (CAC) was utilized to investigate the antitumor effect of PX-12, a Trx-1 inhibitor. A knockin mouse with the Txn1(KK81-82EE) mutation was generated via CRISPR/Cas9, and CAC was induced in knockin and wild-type mice. Results: Nuclear translocation of Trx-1 was induced by IL-6, and inhibition of this translocation reversed IL-6-induced epithelial-to-mesenchymal transition, invasion and metastasis. Karyopherin α1 was found to specifically mediate IL-6-induced translocation of the Trx-1-pSTAT3 complex into the nucleus. Nuclear Trx-1 expression was closely correlated with lymph node metastasis and distant metastasis in human CRC. In addition, nuclear staining of Trx-1 showed significant positive correlation with nuclear staining of pSTAT3 in human CRC tissues. PX-12, an inhibitor of Trx-1, significantly impaired the activation of STAT3 and suppressed the development of AOM/DSS-induced CAC in mice. Moreover, AOM/DSS-induced nuclear Trx-1 expression was suppressed in Txn1(KK81-82EE) mice, which inhibited STAT3 activation and cancer progression. Conclusions: These results provide new insights into the mechanisms of STAT3 activation triggered by IL-6 and identify nuclear translocation of Trx-1 as a potential therapeutic target for the treatment of CRC and CAC.

Thioredoxin 1 supports colorectal cancer cell survival and promotes migration and invasion under glucose deprivation through interaction with G6PD.

Overcoming energy stress is a critical step for cells in solid tumors. Under this stress microenvironment, cancer cells significantly alter their energy metabolism to maintain cell survival and even metastasis. Our previous studies have shown that thioredoxin-1 (Trx-1) expression is increased in colorectal cancer (CRC) and promotes cell proliferation. However, the exact role and mechanism of how Trx-1 is involved in energy stress are still unknown. Here, we observed that glucose deprivation of CRC cells led to cell death and promoted the migration and invasion, accompanied by upregulation of Trx-1. Increased Trx-1 supported CRC cell survival under glucose deprivation. Whereas knockdown of Trx-1 sensitized CRC cells to glucose deprivation-induced cell death and reversed glucose deprivation-induced migration, invasion, and epithelial-mesenchymal transition (EMT). Furthermore, we identified glucose-6-phosphate dehydrogenase (G6PD) interacting with Trx-1 by HuPortTM human protein chip, co-IP and co-localization. Trx-1 promoted G6PD protein expression and activity under glucose deprivation, thereby increasing nicotinamide adenine dinucleotide phosphate (NADPH) generation. Moreover, G6PD knockdown sensitized CRC cells to glucose deprivation-induced cell death and suppressed glucose deprivation-induced migration, invasion, and EMT. Inhibition of Trx-1 and G6PD, together with inhibition of glycolysis using 2-deoxy-D-glucose (2DG), resulted in significant anti-tumor effects in CRC xenografts in vivo. These findings demonstrate a novel mechanism and may represent a new effective therapeutic regimen for CRC.