BACKGROUND: Cluster of differentiation 8 positive (CD8 + ) T cells play a crucial role in the response against tumors, including hepatocellular carcinoma (HCC), where their dysfunction is commonly observed. While the association between elevated peroxisome proliferator-activated receptor alpha (PPARα) expression in HCC cells and exosomes and unfavorable prognosis in HCC patients is well-established, the underlying biological mechanisms by which PPARα induces CD8 + T cell exhaustion mediated by HCC exosomes remain poorly understood. METHODS: Bioinformatics analyses and dual-luciferase reporter assays were used to investigate the regulation of microRNA-27b-3p ( miR-27b-3p ) and thymocyte selection-associated high mobility group box ( Tox ) by Pparα . In vitro and in vivo experiments were conducted to validate the effects of HCC-derived exosomes, miR-27b-3p overexpression, and Pparα on T cell function. Exosome characterization was confirmed using transmission electron microscopy, Western blotting, and particle size analysis. Exosome tracing was performed using small animal in vivo imaging and confocal microscopy. The expression levels of miR-27b-3p , Pparα , and T cell exhaustion-related molecules ( Tox , Havcr2 , and Pdcd1 ) were detected using quantitative reverse transcription polymerase chain reaction analysis, Western blotting analysis, immunofluorescence staining, and flow cytometry analysis. RESULTS: Pparα expression was significantly increased in HCC and negatively correlated with prognosis. It showed a positive correlation with Tox and a negative correlation with miR-27b-3p . The overexpressed Pparα from HCC cells was delivered to CD8 + T cells via exosomes, which absorbed miR-27b-3p both in vitro and in vivo , acting as "miRNA sponges". Further experiments demonstrated that Pparα can inhibit the negative regulation of Tox mediated by miR-27b-3p through binding to its 3'untranslated regions. CONCLUSIONS HCC-derived exosomes deliver Pparα to T cells and promote CD8 + T cell exhaustion and malignant progression of HCC via the miR-27b-3p /TOX regulatory axis. The mechanisms underlying T-cell exhaustion in HCC can be utilized for the advancement of anticancer therapies.
MicroRNAs/metabolism* ; PPAR alpha/genetics* ; Carcinoma, Hepatocellular/genetics* ; Humans ; Liver Neoplasms/genetics* ; CD8-Positive T-Lymphocytes/immunology* ; Exosomes/metabolism* ; Animals ; Cell Line, Tumor ; Mice ; High Mobility Group Proteins/genetics* ; Male ; T-Cell Exhaustion

Purpose To explore the value of contrast-enhanced ultrasound(CEUS)in the differential diagnosis of gallbladder polypoid lesions(GPLs)(diameter≥10 mm).Materials and Methods A prospective enrollment of 229 patients with GPLs who underwent cholecystectomy in 17 hospitals from December 1 2021 to June 30 2024 was conducted to analyze the relationship between general data,conventional ultrasound,CEUS characteristics and the nature of GPLs.Multivariate Logistic regression was employed to identify independent risk factors for neoplastic polyps,the differential diagnostic value of different indicators was compared.Results Among 229 patients with GPLs,there were 108 cases of cholesterol polyps,102 cases of adenoma and 19 cases of gallbladder cancer.Age(Z=-4.476,P<0.001),polyp number(χ2=15.561,P<0.001),diameter(Z=-8.149,P<0.001),echogenicity(χ2=9.241,P=0.010),vascularity(χ2=23.107,P<0.001),enhancement intensity(χ2=47.610,P<0.001),enhancement pattern(χ2=6.468,P=0.011),vascular type(χ2=84.470,P<0.001),integrity of gallbladder wall(χ2=7.662,P=0.006)and stalk width(Z=-9.831,P<0.001)between cholesterol polyps and neoplastic polyps were statistically significant.Age,location,diameter,echogenicity,enhancement pattern,vascular type and stalk width between adenoma and gallbladder cancer were statistically significant(Z=-4.333,-3.902,-5.042,all P<0.05).Multivariate Logistic regression analysis showed that hyper-enhancement,branched vascular type and stalk width were independent risk factors for neoplastic polyps(OR=4.563,5.770,3.075,all P<0.001).The combination of independent risk factors was better than single factor and diameter in the differential diagnosis of cholesterol polyps and neoplastic polyps(all P<0.01).Conclusion CEUS can effectively identify the nature of GPLs and provide a valuable imaging reference for the selection of treatment methods.

Objective:To investigate the molecular mechanism of PDGFC regulated by HuR in breast cancer cells.Methods:Through the software analysises,we first predicted the HuR-binding sites on the PDGFC 3'-UTR in breast cancer cells;An RNA-immunoprecipitation tested the interaction of HuR with the PDGFC mRN after adding PDGFC stimulation;Luciferase experiments tested the HuR-binding sites of PDGFC regulated by HuR through structuring five truncated of PDGFC 3'UTR.Results:We found five HuR-binding sites in the 3'UTR of PDGFC by software prediction;The RNA-immunoprecipitation showed the co-immunoprecipitation of HuR and PDGFC mRN after adding PDGFC stimulation confirming the direct association of HuR with the PDGFC;Luciferase experiments ofPDGFC mRNA 3'UTR showed that PDGFC regulated by the second and fourth HuR-binding sites.Conclusions:This study reveals the molecular mechanism of PDGFC regulated by HuR through binding to PDGFC mRNA 3'UTR in breast cancer cells,and provided rationale for the development of strategies in the clinical diagnosis and treatment for breast cancer.