Comprehensive analysis of the clinical significance, immune infiltration, and biological role of MARCH ligases in HCC.

The membrane-associated RING-CH (MARCH) family, a member of the E3 ubiquitin ligases, has been confirmed by a growing number of studies to be associated with immune function and has been highlighted as a potential immunotherapy target. In our research, hepatocellular carcinoma (HCC) patients were divided into C1 and C2 MARCH ligase-related patterns by the non-negative matrix factorization (NMF) algorithm. Multiple analyses revealed that the MARCH ligase-related cluster was related to prognosis, clinicopathological characteristics, and the tumor immune microenvironment (TIME). Next, the signature (risk score) of the MARCH prognosis was constructed, including eight genes associated with the MARCH ligase (CYP2C9, G6PD, SLC1A5, SPP1, ANXA10, CDC20, PON1, and FTCD). The risk score showed accuracy and stability. We found that the correlations between risk score and TIME, tumor mutation burden (TMB), prognosis, and clinicopathological characteristics were significant. Additionally, the risk score also had important guiding significance for HCC treatment, including chemotherapy, immunotherapy, and transarterial chemoembolization (TACE).

Down-regulation of circPTTG1IP induces hepatocellular carcinoma development via miR-16-5p/RNF125/JAK1 axis.

Circular RNAs are known to regulate the biological processes of hepatocellular carcinoma (HCC), and humans with Down syndrome are at low risk of developing solid tumors due to the amplification of several tumor suppressor genes on human chromosome 21 (HSA21). Here, we aimed to investigate the potential role of circRNAs originating from HSA21 in the progression of HCC. CircRNA-sequencing was performed to analyze differentially expressed circRNAs in 4 HCC and peritumor tissues, and circRNAs originating from HSA21 were further analyzed. Circ_0061984 (circPTTG1IP) was chosen for further study because it showed the lowest expression in HCC tissues, and qRT-PCR was used to confirm the expression of circPTTG1IP in HCC patient tissues. The biological function of circPTTG1IP was detected in HCC cells both in vivo and in vitro. Moreover, luciferase reporter assays, circRNA immunoprecipitation, and fluorescence in situ hybridization (FISH) were used to investigate the potential mechanism of circPTTG1IP. Finally, the possible mechanisms of filgotinib in circPTTG1IP-driven HCC were assessed. CircPTTG1IP expression was decreased in HCC compared to peritumoral tissues. Moreover, low circPTTG1IP expression was revealed to be associated with a poor prognosis of HCC patients. Elevation of circPTTG1IP was revealed to inhibit HCC development both in vitro and in vivo. Mechanistically, circPTTG1IP was shown to function as a competing endogenous RNA (ceRNA) of RNF125 by binding miR-16-5p to increase the level of the E3 ubiquitin ligase RNF125, which further ubiquitinated and degraded JAK1 protein. Finally, we demonstrated that administration of filgotinib, a JAK1 inhibitor, restricted HCC progression induced by low circPTTG1IP expression. Thus, we revealed that circPTTG1IP is a novel tumor suppresser circRNA in HCC and that a low circPTTG1IP level promotes HCC development via the miR-16-5p/RNF125/JAK1 axis. Patients with low circPTTG1IP may benefit from filgotinib treatment.

Identification of hepatocellular carcinoma-related genes associated with macrophage differentiation based on bioinformatics analyses.

Macrophage differentiation is associated with tumorigenesis, including the tumorigenesis of hepatocellular carcinoma (HCC). Herein, we explored the value of macrophage differentiation-associated genes (MDGs) in the prognosis of HCC using data from The Cancer Genome Atlas (TCGA) and the International Cancer Genome Consortium (ICGC) databases. We performed multivariate Cox regression analyses to identify the hub genes affecting HCC patient prognoses. The correlations between hub genes and macrophage differentiation and immune checkpoint inhibitors (PD-1, PD-L1, and CTLA4) were investigated. Finally, the potential mechanism was examined with gene set enrichment analysis (GSEA). In total, seventeen differentially expressed MDGs were obtained after intersecting data from the two databases. Multivariate analysis indicated that CDC42 expression was an independent prognostic indicator in both databases. Furthermore, CDC42 showed a strong correlation with the tumor infiltration levels of immune cells in HCC tissue. Correlation analysis revealed that CDC42 expression was positively associated with M2 macrophage markers and immune checkpoint inhibitors, which indicated that CDC42 expression might be related to M2 macrophage differentiation and HCC cell immune tolerance. Finally, GSEA showed that CDC42 expression was most significantly related to the Wnt signaling pathway. In conclusion, this study showed that CDC42 expression might be an important MDG in HCC and may prove to be a new gene for studying macrophage differentiation in HCC. Abbreviations: HCC: hepatocellular carcinoma; TCGA: The Cancer Genome Atlas; ICGC: International Cancer Genome Consortium; GSEA: gene set enrichment analysis; GO: Gene Ontology; KEGG: Kyoto Encyclopedia of Genes and Genomes; ROC: receiver operating characteristic; K-M: Kaplan-Meier; AUC: the area under the ROC curve; TNM: Tumor size/lymph nodes/distance metastasis.

Expression of GLS1 in intrahepatic cholangiocarcinoma and its clinical significance.

Kidney­type glutaminase (GLS1) plays a significant role in tumor metabolism. Our recent studies demonstrated that GLS1 was aberrantly expressed in hepatocellular carcinoma (HCC) and facilitated tumor progression. However, the roles of GLS1 in intrahepatic cholangiocarcinoma (ICC) remain largely unknown. Thus, the aim of this study was to evaluate the expression and clinical significance of GLS1 in ICC. For this purpose, combined data from the Oncomine database with those of immunohistochemistry were used to determine the expression levels of GLS1 in cancerous and non­cancerous tissues. Second, a wound­healing assay and Transwell assay were used to observe the effects of the knockdown and overexpression of GLS1 on the invasion and migration of ICC cells. We examined the associations between the expression of GLS1 and epithelial­mesenchymal transition (EMT)­related markers by western blot analysis. Finally, we examined the associations between GLS1 levels and clinicopathological factors or patient prognosis. The results revealed that GLS1 was overexpressed in different digestive system tumors, including ICC, and that GLS1 expression in ICC tissue was higher than that in peritumoral tissue. The overexpression of GLS1 in RBE cells induced metastasis and invasion. Moreover, the EMT­related markers, E­cadherin and Vimentin, were regulated by GLS1 in ICC cells. By contrast, the knockdown of GLS1 expression in QBC939 cells yielded opposite results. Clinically, a high expression of GLS1 in ICC samples negatively correlated with E­cadherin expression and positively correlated with Vimentin expression. GLS1 protein expression was associated with tumor differentiation (P=0.001) and lymphatic metastasis (P=0.029). Importantly, patients with a high GLS1 expression had a poorer overall survival (OS) and a shorter time to recurrence than patients with a low GLS1 expression. Multivariate analysis indicated that GLS1 expression was an independent prognostic indicator. On the whole, the findings of this study demonstrated that GLS1 is an independent prognostic biomarker of ICC. GLS1 facilitates ICC progression and may thus prove to be a therapeutic target in ICC.