Objective To explore the mechanism of mTOR-mediated liver cancer cell invasion.Methods q-PCR was used to check the expression of miR-27a and GP73;miR-27a mimics were transfected into GP73-high expressing M97H cells and miR-27a inhibitors were transfected into GP73-low expressing HepG2 cells,q-PCR and Western blot were performed to observe the expression of GP73;Dual-luciferase assay was also performed to verify the binding sites of miR-27a in GP73 3'UTR;miR-27a mimics were transfected into M97H cells and miR-27a inhibitors were transfected into HepG2 cells,Transwell assay was used to measure cell invasion.Results mTOR downregulated miR-27a and upregulated GP73;GP73 was downregulated by miR-27a and upregulated by miR-27a suppression;GP73 was a target gene of miR-27a;miR-27a inhibited the invasion of M97H cells rather than HepG2 cells.Conclusions miR-27a is negatively regulated by mTOR and inhibits liver cancer cell invasion via targeting GP73.

BACKGROUND: Liver cancer is largely resistant to chemotherapy. This study aimed to identify the effective chemotherapeutics for β-catenin-activated liver cancer which is caused by gain-of-function mutation of catenin beta 1 ( CTNNB1 ), the most frequently altered proto-oncogene in hepatic neoplasms. METHODS: Constitutive β-catenin-activated mouse embryonic fibroblasts (MEFs) were established by deleting exon 3 ( β-catenin Δ(ex3)/+ ), the most common mutation site in CTNNB1 gene. A screening of 12 widely used chemotherapy drugs was conducted for the ones that selectively inhibited β-catenin Δ(ex3)/+ but not for wild-type MEFs. Untargeted metabolomics was carried out to examine the alterations of metabolites in nucleotide synthesis. The efficacy and selectivity of methotrexate (MTX) on β-catenin-activated human liver cancer cells were determined in vitro . Immuno-deficient nude mice subcutaneously inoculated with β-catenin wild-type or mutant liver cancer cells and hepatitis B virus ( HBV ); β-catenin lox(ex3)/+ mice were used, respectively, to evaluate the efficacy of MTX in the treatment of β-catenin mutant liver cancer. RESULTS: MTX was identified and validated as a preferential agent against the proliferation and tumor formation of β-catenin-activated cells. Boosted nucleotide synthesis was the major metabolic aberration in β-catenin-active cells, and this alteration was also the target of MTX. Moreover, MTX abrogated hepatocarcinogenesis of HBV ; β-catenin lox(ex3)/+ mice, which stimulated concurrent Ctnnb1- activated mutation and HBV infection in liver cancer. CONCLUSION MTX is a promising chemotherapeutic agent for β-catenin hyperactive liver cancer. Since repurposing MTX has the advantages of lower risk, shorter timelines, and less investment in drug discovery and development, a clinical trial is warranted to test its efficacy in the treatment of β-catenin mutant liver cancer.
Mice ; Animals ; Humans ; Methotrexate/therapeutic use* ; Mice, Nude ; beta Catenin/metabolism* ; Fibroblasts/metabolism* ; Liver Neoplasms/metabolism* ; Hepatitis B virus ; Nucleotides