BACKGROUND: Atherosclerosis is a globally prevalent chronic inflammatory disease with high morbidity and mortality. The development of atherosclerotic lesions is determined by macrophages. This study aimed to investigate the specific role of myeloid-derived CD147 (cluster of differentiation 147) in atherosclerosis and its translational significance. METHODS AND RESULTS: We generated mice with a myeloid-specific knockout of CD147 and mice with restricted CD147 overexpression, both in an apoE-deficient (ApoE ^–/– ) background. Here, the myeloid-specific deletion of CD147 ameliorated atherosclerosis and inflammation. Consistent with our in vivo data, macrophages isolated from myeloid-specific CD147 knockout mice exhibited a phenotype shift from proinflammatory to anti-inflammatory macrophage polarization in response to lipopolysaccharide/IFN (interferon)-γ. These macrophages demonstrated a weakened proinflammatory macrophage phenotype, characterized by reduced production of NO and reactive nitrogen species derived from iNOS (inducible NO synthase). Mechanistically, the TRAF6 (tumor necrosis factor receptor–associated factor 6)-IKK (inhibitor of κB kinase)-IRF5 (IFN regulatory factor 5) signaling pathway was essential for the effect of CD147 on proinflammatory responses. Consistent with the reduced size of the necrotic core, myeloid-specific CD147 deficiency diminished the susceptibility of iNOS-mediated late apoptosis, accompanied by enhanced efferocytotic capacity mediated by increased secretion of GAS6 (growth arrest–specific 6) in proinflammatory macrophages. These findings were consistent in a mouse model with myeloid-restricted overexpression of CD147. Furthermore, we developed a new atherosclerosis model in ApoE ^–/– mice with humanized CD147 transgenic expression and demonstrated that the administration of an anti-human CD147 antibody effectively suppressed atherosclerosis by targeting inflammation and efferocytosis. CONCLUSIONS: Myeloid CD147 plays a crucial role in the growth of plaques by promoting inflammation in a TRAF6-IKK-IRF5–dependent manner and inhibiting efferocytosis by suppressing GAS6 during proinflammatory conditions. Consequently, the use of anti-human CD147 antibodies presents a complementary therapeutic approach to the existing lipid-lowering strategies for treating atherosclerotic diseases.

Background: The mechanism of hepatitis B virus (HBV)‐induced carcinogenesis remains an area of interest. The accumulation of hepatitis B surface antigen in the endoplasmic reticulum (ER) of hepatocytes stimulates persistent ER stress. Activity of the unfolded protein response (UPR) pathway of ER stress may play an important role in inflammatory cancer transformation. How the protective UPR pathway is hijacked by cells as a tool for malignant transformation in HBV‐related hepatocellular carcinoma (HCC) is still unclear. Here, we aimed to define the key molecule hyaluronan‐mediated motility receptor (HMMR) in this process and explore its role under ER stress in HCC development. Methods: An HBV‐transgenic mouse model was used to characterize the pathological changes during the tumor progression. Proteomics and transcriptomics analyses were performed to identify the potential key molecule, screen the E3 ligase, and define the activation pathway. Quantitative real‐time PCR and Western blotting were conducted to detect the expression of genes in tissues and cell lines. Luciferase reporter assay, chromatin immunoprecipitation, coimmunoprecipitation, immunoprecipitation, and immunofluorescence were employed to investigate the molecular mechanisms of HMMR under ER stress. Immunohistochemistry was used to clarify the expression patterns of HMMR and related molecules in human tissues. Results: We found sustained activation of ER stress in the HBV‐transgenic mouse model of hepatitis‐fibrosis‐HCC. HMMR was transcribed by c/EBP homologous protein (CHOP) and degraded by tripartite motif containing 29 (TRIM29) after ubiquitination under ER stress, which caused the inconsistent expression of mRNA and protein. Dynamic expression of TRIM29 in the HCC progression regulated the dynamic expression of HMMR. HMMR could alleviate ER stress by increasing autophagic lysosome activity. The negative correlation between HMMR and ER stress, positive correlation between HMMR and autophagy, and negative correlation between ER stress and autophagy were verified in human tissues. Conclusions: This study identified the complicated role of HMMR in autophagy and ER stress, that HMMR controls the intensity of ER stress by regulating autophagy in HCC progression, which could be a novel explanation for HBV‐related carcinogenesis.

Pyroptosis is an inflammatory form of programmed cell death that is involved in various cancers, including hepatocellular carcinoma (HCC). Long non-coding RNAs (lncRNAs) were recently verified as crucial mediators in the regulation of pyroptosis. However, the role of pyroptosis-related lncRNAs in HCC and their associations with prognosis have not been reported. In this study, we constructed a prognostic signature based on pyroptosis-related differentially expressed lncRNAs in HCC. A co-expression network of pyroptosis-related mRNAs–lncRNAs was constructed based on HCC data from The Cancer Genome Atlas. Cox regression analyses were performed to construct a pyroptosis-related lncRNA signature (PRlncSig) in a training cohort, which was subsequently validated in a testing cohort and a combination of the two cohorts. Kaplan–Meier analyses revealed that patients in the high-risk group had poorer survival times. Receiver operating characteristic curve and principal component analyses further verified the accuracy of the PRlncSig model. Besides, the external cohort validation confirmed the robustness of PRlncSig. Furthermore, a nomogram based on the PRlncSig score and clinical characteristics was established and shown to have robust prediction ability. In addition, gene set enrichment analysis revealed that the RNA degradation, the cell cycle, the WNT signaling pathway, and numerous immune processes were significantly enriched in the high-risk group compared to the low-risk group. Moreover, the immune cell subpopulations, the expression of immune checkpoint genes, and response to chemotherapy and immunotherapy differed significantly between the high- and low-risk groups. Finally, the expression levels of the five lncRNAs in the signature were validated by quantitative real-time PCR. In summary, our PRlncSig model shows significant predictive value with respect to prognosis of HCC patients and could provide clinical guidance for individualized immunotherapy.

Anoikis resistance in hepatocellular carcinoma (HCC) cells boosts survival and metastasis. This study aimed to establish an anoikis‐related genes (ARGs)‐based model for predicting HCC patients’ outcomes and investigate the clinicopathological significance and function of crucial ARGs. The transcriptional expression patterns for HCC cohorts were compiled from TCGA, GEO and ICGC. Univariate and LASSO multivariate analyses were performed to screen for prognostic ARGs. Gain‐ and loss‐of‐function studies, RNA sequencing, and mass spectrometry were employed to elucidate the underlying mechanisms of ARGs in HCC. We established a five‐gene ARGs risk model for HCC prognosis, with an AUC value of 0.812 for 1‐year survival. Among the five genes, Rac family small GTPase 3 (RAC3) was upregulated in HCC relative to adjacent normal tissues and negatively correlated to overall survival and disease‐free survival of patients with HCC. Silence of RAC3 in HCC cells resulted in an increased cell apoptosis and diminished cell proliferation and invasion. Mechanistically, we uncovered that RAC3 binding with SOX6 propelled the advancement of HCC cells through NNMT‐mediated stimulation of the cAMP/MAPK/Rap1 signaling. In particular, EHop‐016, a small molecule inhibitor targeting RAC3, significantly suppressed HCC progression.

Up to 50% of hepatocellular carcinoma (HCC) is caused by hepatitis B virus (HBV) infection, and the surface protein of HBV is essential for the progression of HBV-related HCC. The expression of large HBV surface antigen (LHB) is presented in HBV-associated HCC tissues and is significantly associated with the development of HCC. Gene set enrichment analysis revealed that LHB overexpression regulates the cell cycle process. Excess LHB in HCC cells induced chronic endoplasmic reticulum (ER) stress and was significantly correlated with tumor growth in vivo. Cell cycle analysis showed that cell cycle progression from G1 to S phase was greatly enhanced in vitro. We identified intensive crosstalk between ER stress and cell cycle progression in HCC. As an important regulator of the G1/S checkpoint, p27 was transcriptionally upregulated by transcription factors ATF4 and XBP1s, downstream of the unfolded protein response pathway. Moreover, LHB-induced ER stress promoted internal ribosome-entry-site-mediated selective translation of p27, and E3 ubiquitin ligase HRD1-mediated p27 ubiquitination and degradation. Ultimately, the decrease in p27 protein levels reduced G1/S arrest and promoted the progress of HCC by regulating the cell cycle.

Hepatocellular carcinoma (HCC) represents one of the most lethal malignancies worldwide and is characterized by profound metabolic reprogramming during its development. Paraoxonase 1 (PON1), a liver-synthesized secretory protein involved in lipid metabolism, has an incompletely defined role in cancer biology. This study aimed to systematically investigate the expression pattern, clinical features, and biological function of PON1 in HCC through an integrated approach combining data mining, RNA-seq and experimental verification. Our results demonstrated that PON1 expression is significantly downregulated in HCC tissues compared with adjacent tissues. Clinically, significant disparities were observed in gender (χ² = 19.305, p < 0.0001), tumor stage (χ² = 18.030, p = 0.0004), and tumor grade (χ² = 13.391, p = 0.0039) between patients with high and low PON1 expression in HCC. Low PON1 expression was associated with poor prognosis (TCGA_LIHC, log-rank: χ² = 9.290, p = 0.0023; ICGC_LIRI, log-rank: χ² = 8.469, p = 0.0036; GSE14520, log-rank: χ² = 9.746, p = 0.0018). Univariate and multivariate Cox regression analyses revealed PON1 as an independent prognostic biomarker. Pathway analysis showed that PON1-positively correlated genes enriched in pathways such as peroxisome and fatty acid degradation, whereas PON1-negatively correlated genes mainly in the cell cycle pathway. Functional experiments confirmed that knockdown of PON1 promoted HCC cell proliferation, migration, invasion and inhibited apoptosis, whereas overexpression of PON1 reversed these malignant phenotypes. Mechanistically, we uncovered that PON1 exerts its tumor-suppressive effects by negatively regulating TANK and CXCL3, key molecules of the NOD-like receptor signaling pathway. In summary, our findings identify PON1 as an independent prognostic biomarker in HCC and demonstrate the tumor-suppressive role of PON1, indicating its potential as a therapeutic target for HCC.