To clarify the significance of circulating tumor cells (CTC) undergoing epithelial-mesenchymal transition (EMT) in patients with hepatocellular carcinoma (HCC), we used an advanced CanPatrol CTC-enrichment technique and hybridization to enrich and classify CTC from blood samples. One hundred and one of 112 (90.18%) patients with HCC were CTC positive, even with early-stage disease. CTCs were also detected in 2 of 12 patients with hepatitis B virus (HBV), both of whom had small HCC tumors detected within 5 months. CTC count ≥16 and mesenchymal-CTC (M-CTC) percentage ≥2% prior to resection were significantly associated with early recurrence, multi-intrahepatic recurrence, and lung metastasis. Postoperative CTC monitoring in 10 patients found that most had an increased CTC count and M-CTC percentage before clinically detectable recurrence nodules appeared. Analysis of HCC with high CTC count and high M-CTC percentage identified 67 differentially expressed cancer-related genes involved in cancer-related biological pathways (e.g., cell adhesion and migration, tumor angiogenesis, and apoptosis). One of the identified genes, BCAT1, was significantly upregulated, and knockdown in Hepg2, Hep3B, and Huh7 cells reduced cell proliferation, migration, and invasion while promoting apoptosis. A concomitant increase in epithelial marker expression (EpCAM and E-cadherin) and reduced mesenchymal marker expression (vimentin and Twist) suggest that BCAT1 may trigger the EMT process. Overall, CTCs were highly correlated with HCC characteristics, representing a novel marker for early diagnosis and a prognostic factor for early recurrence. BCAT1 overexpression may induce CTC release by triggering EMT and may be an important biomarker of HCC metastasis. In liver cancer, CTC examination may represent an important "liquid biopsy" tool to detect both early disease and recurrent or metastatic disease, providing cues for early intervention or adjuvant therapy. .
Periostin neutralizing Ab. The hybridoma cell lines secreting mouse mAb against mouse periostin were generated by Abmart Co., according to the standard hybridoma technique (72). The mouse mAbs were purified by Protein A affinity chromatograph. mAb purity was confirmed by HPLC. The concentrations of the obtained mAbs were measured by Mouse IgG ELISA Quantitation kit (Bethyl Laboratories), following the manufacturer's instructions. The kinetic parameters of the mAbs were determined using a Biacore T100 instrument (Biacore AB). Purified Ab was diluted in saline and injected at a dose of 5 mg/kg into db/db mice for 2 weeks.Statistics. All values are shown as mean ± SEM. Statistical differences were determined by 2-way ANOVA with Bonferroni-adjusted post-test or by 2-tailed Student's t test. A P value less than 0.05 was considered significant.
Both epidemiologic and experimental animal studies demonstrate that chronic psychological stress exerts adverse effects on the initiation and/or progression of many diseases. However, intergenerational effects of this environmental information remains poorly understood. Here, using a C57BL/6 mouse model of restraint stress, we show that offspring of stressed fathers exhibit hyperglycemia due to enhanced hepatic gluconeogenesis and elevated expression of PEPCK. Mechanistically, we identify an epigenetic alteration at the promoter region of the Sfmbt2 gene, a maternally imprinted polycomb gene, leading to a downregulation of intronic microRNA-466b-3p, which post-transcriptionally inhibits PEPCK expression. Importantly, hyperglycemia in F1 mice is reversed by RU486 treatment in fathers, and dexamethasone administration in F0 mice phenocopies the roles of restraint stress. Thus, we provide evidence showing the effects of paternal psychological stress on the regulation of glucose metabolism in offspring, which may have profound implications for our understanding of health and disease risk inherited from fathers.
Background and Aims
Nonalcoholic fatty liver disease (NAFLD) is characterized by accumulation of excessive triglycerides (TGs) in hepatocytes. Obesity is a major risk factor for developing fatty liver, although the intracellular molecular basis remains largely unclear. N6‐methyladenosine (m6A) RNA methylation is the most common internal modification in eukaryotic mRNA.
Approach and Results
In the present study, by m6A sequencing and RNA sequencing, we found that both m6A enrichment and mRNA expression of lipogenic genes were significantly increased in leptin‐receptor–deficient db/db mice. Importantly, our results showed that YT521‐B homology domain‐containing 2 (Ythdc2), an m6A reader, was markedly down‐regulated in livers of obese mice and NAFLD patients. Suppression of Ythdc2 in livers of lean mice led to TG accumulation, whereas ectopic overexpression of Ythdc2 in livers of obese mice improved liver steatosis and insulin resistance. Mechanistically, we found that Ythdc2 could bind to mRNA of lipogenic genes, including sterol regulatory element‐binding protein 1c, fatty acid synthase, stearoyl‐CoA desaturase 1, and acetyl‐CoA carboxylase 1, to decrease their mRNA stability and inhibit gene expression.
Conclusions
Our findings describe an important role of the m6A reader, Ythdc2, for regulation of hepatic lipogenesis and TG homeostasis, which might provide a potential target for treating obesity‐related NAFLD.
Ubiquitin-specific protease 14 (USP14) is one of the major proteasome-associated deubiquitinating enzymes critical for proteome homeostasis. However, substrates of USP14 remain largely unknown, hindering the understanding of its functional roles. Here we conduct a comprehensive proteome, ubiquitinome and interactome analysis for USP14 substrate screening. Bioinformatics analysis reveals broad new potential roles of USP14, especially in lipid and carbohydrate metabolism. Among the potential substrates identified, we show that fatty acid synthase (FASN), a key enzyme involved in hepatic lipogenesis, is a bona fide substrate of USP14. USP14 directly interacts with and increases FASN stability. As a result, overexpression of USP14 promotes liver triglyceride accumulation in C57BL/6 mice, whereas genetic ablation or pharmacological inhibition of USP14 ameliorates hepatosteatosis, hyperglycemia and insulin resistance in obese mice. In conclusion, our findings reveal for the first time an indispensable role of USP14 in hepatosteatosis through FASN stabilization.
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