ABSTRACT
[This corrects the article DOI: 10.7150/ijbs.71809.].
ABSTRACT
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.
Subject(s)
Colorectal Neoplasms , Thioredoxins , Cell Line, Tumor , Cell Movement/genetics , Cell Proliferation , Cell Survival/genetics , Colorectal Neoplasms/metabolism , Deoxyglucose , Epithelial-Mesenchymal Transition , Gene Expression Regulation, Neoplastic , Glucose , Glucosephosphate Dehydrogenase/genetics , Glucosephosphate Dehydrogenase/metabolism , Humans , NADP/metabolism , Thioredoxins/genetics , Thioredoxins/metabolism , Tumor MicroenvironmentABSTRACT
Background: Our previous study has shown that Da0324, a curcumin analog, exhibited significantly improved stability and antitumor activity. However, the molecular mechanisms of action of Da0324 remain poorly understood. Long non-coding RNA (lncRNA) has been shown to play a key role in tumor progression. Here, we aim to investigate the molecular mechanisms underlying the anti-cancer activity of Da0324 by regulating the lncRNA HOTAIRM1. Methods: Gastric cancer cell lines were treated with Da0324 and/or transfected with lentiviral vector expressing HOTAIRM1 shRNA, and/or miR-29b-1-5p mimics and/or small interference RNA (siRNA) against PHLPP1, or HOTAIRM1 siRNA or lentiviral vector expressing HOTAIRM1, as needed. The expression of HOTAIRM1, miR-29b-1-5p and PHLPP1 in GC cells was determined by Real-Time PCR. Cell growth was examined by CCK-8 assay and colony formation assay in vitro. The targeted relationship between HOTAIRM1 and miR-29b-1-5p was verified by luciferase reporter gene assay. PHLPP1 protein expression was examined by Western blotting. Results: Da0324 increased the expression of HOTAIRM1 in GC cells. HOTAIRM1 expression was significantly down-regulated in GC tissues, and the low expression of HOTAIRM1 was associated with the shorter survival rate of GC patients based on the TCGA database. Knockdown of HOTAIRM1 promoted GC cell proliferation whereas overexpression of HOTAIRM1 inhibited GC cell proliferation as demonstrated by CCK-8 and colony formation assays. Moreover, knockdown of HOTAIRM1 reversed the Da0324-mediated growth inhibition of GC cells. Furthermore, HOTAIRM1 acted as a sponge for miR-29b-1-5p and PHLPP1 is regulated by the HOTAIRM1/miR-29b-1-5p axis in GC cells. Overexpression of miR-29b-1-5p or knockdown of PHLPP1 reversed the ability of Da0324 to inhibit the growth of GC cells. Conclusions: Our data suggest that Da0324 exerts antitumor activity by regulating HOTAIRM1/miR-29b-1-5p/PHLPP1 axis in GC cells, and provide new insights into the anti-cancer mechanism of Da0324.
