METHODS: The RNA expression profiles and corresponding clinical data of HCC were retrieved from The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), and International Cancer Genome Consortium (ICGC). Univariate Cox regression analysis was performed to identify the relevant prognostic genes, and Lasso Cox regression analysis was employed to calculate the risk score. The relationship between the risk score and clinicopathological characteristics, immune cell infiltration, and immune checkpoint expression was analyzed.
RESULTS: A prognostic risk model for HCC was constructed from the identified CDRGs and patients were subgrouped based on risk score. High-risk patients for HCC exhibited a significantly lower overall survival (OS) rate than the low-risk patients. In addition, the receiver operating characteristic (ROC) curve demonstrated the predictive ability of the risk score. Patients in the high-risk group exhibited lower immune cell infiltration and higher expression levels of immune checkpoint molecules.
CONCLUSIONS: The cell death-related signature established herein provides a valuable predictive tool for survival and holds promise as a potential therapeutic biomarker for HCC.
METHODS: Reverse-transcription-polymerase chain reaction was employed to measure the expression of plasmacytoma variant translocation 1 (PVT1), microRNAs (miRNAs), and SIRT3, and the dual-luciferase assay was used to determine their interaction. Electron microscopy observes autophagosomes, green fluorescent protein-microtubule-associated protein 1 light chain 3 (GFP-LC3) staining, and immunoblot analysis with antibodies against LC3，beclin-1, and P62 were conducted to measure autophagy. Cellular senescence was determined using immunoblot analysis with anti-phosphorylated retinoblastoma and senescence-associated β-galactosidase staining.
RESULTS: Women with higher estrogen levels (during the 10-13th day of the menstrual cycle or premenopausal) exhibit markedly higher serum levels of PVT1 than women with lower estrogen levels (during the menstrual period or postmenopausal). The dual-luciferase assay showed that PVT1 acts as a sponge for miR-31, and miR-31 binds to its target gene, SIRT3. The 17β-E2 treatment increased the expression of PVT1 and SIRT3 and downregulated miR-31 expression in human umbilical vein endothelial cells (HUVECs). Consistently, PVT1 overexpression suppresses miR-31 expression, promotes 17β-E2-induced autophagy, and inhibits H2O2-induced senescence. miR-31 inhibitor increases SIRT3 expression and leads to activation of 17β-E2-induced autophagy and suppression of H2O2-induced senescence.
CONCLUSION: Our findings demonstrated that 17β-E2 upregulates PVT1 gene expression and PVT1 functions as a sponge to inhibit miR-31, resulting in the upregulation of SIRT3 expression and activation of autophagy and subsequent inhibition of H2O2-induced senescence in HUVECs.