Hepatitis B virus X protein promotes epithelial-mesenchymal transition of hepatocellular carcinoma cells by regulating SOCS1

War or peace: Viruses and metastasis

Metastasis, the dissemination of malignant cells from a primary tumor to secondary sites, poses a catastrophic burden to cancer treatment and is the predominant cause of mortality in cancer patients. Metastasis as one of the main aspects of cancer progression could be strongly under the influence of viral infections. In fact, viruses have been central to modern cancer research and are associated with a great number of cancer cases. Viral-encoded elements are involved in modulating essential pathways or specific targets that are implicated in different stages of metastasis. Considering the continuous emergence of new viruses and the establishment of their contribution to cancer progression, the warfare between viruses and cancer appears to be endless. Here we aimed to review the critical mechanism and pathways involved in cancer metastasis and the influence of viral machinery and various routes that viruses adopt to manipulate those pathways for their benefit.

The role of abnormal ubiquitination in hepatocellular carcinoma pathology

Primary liver cancer is known for its high incidence and fatality rate. Over the years, therapeutic strategies for primary liver cancer have advanced significantly. Nonetheless, a substantial number of patients have not benefited from these methods, underscoring the pressing need for new and effective treatments for primary liver cancer. Ubiquitination is a critical post-translational modification that enables proteins to fulfill their normal biological functions and maintain their expression stability within cells. Importantly, increasing evidence suggests that the progression of liver cancer cells is often accompanied by disruptions in protein ubiquitination and deubiquitination processes. In this comprehensive review, we have compiled pertinent research about dysregulated ubiquitination in hepatocellular carcinoma (HCC) to broaden our understanding in this field. We elucidate the connections between the ubiquitination proteasome system, deubiquitination, and HCC. Furthermore, we shed light on the role of ubiquitination in cells situated within the tumor microenvironment of HCC including its involvement in mediating the activation of oncogenic pathways, reprogramming metabolic processes, and perturbing normal cellular functions. In conclusion, targeting the dysregulation of ubiquitination in HCC holds promise as a prospective and complementary therapeutic approach to existing treatments.

Mechanism-guided fine-tuned microbiome potentiates anti-tumor immunity in HCC

Microbiome, including bacteria, fungi, and viruses, plays a crucial role in shaping distal and proximal anti-tumor immunity. Mounting evidence showed that commensal microbiome critically modulates immunophenotyping of hepatocellular carcinoma (HCC), a leading cause of cancer-related death. However, their role in anti-tumor surveillance of HCC is still poorly understood. Herein, we spotlighted growing interests in how the microbiome influences the progression and immunotherapeutic responses of HCC via changing local tumor microenvironment (TME) upon translocating to the sites of HCC through different "cell-type niches". Moreover, we summarized not only the associations but also the deep insight into the mechanisms of how the extrinsic microbiomes interplay with hosts to shape immune surveillance and regulate TME and immunotherapeutic responses. Collectively, we provided a rationale for a mechanism-guided fine-tuned microbiome to be neoadjuvant immunotherapy in the near future.

Suppression of NF-κB signaling by Pseudorabies virus DNA polymerase processivity factor UL42 via recruiting SOCS1 to promote the ubiquitination degradation of p65

The NF-κB pathway is a critical signaling involved in the regulation of the inflammatory and innate immune responses. Previous studies have shown that Pseudorabies Virus (PRV), a porcine alpha herpesvirus, could lead to the phosphorylation and nucleus translocation of p65 while inhibiting the expression of NF-κB-dependent inflammatory cytokines, which indicated that there may be unknown mechanisms downstream of p65 that downregulate the activation of NF-κB signaling. Here, we found that PRV DNA polymerase factor UL42 inhibited TNFα-, LPS-, IKKα-, IKKβ-, and p65-mediated transactivation of NF-κB signaling, which demonstrated UL42 worked either at or downstream of p65. In addition, it was found that the DNA-binding activity of UL42 was required for inhibition of NF-κB signaling. Importantly, it was revealed that UL42 could induce the ubiquitination degradation of p65 by upregulating the suppressor of cytokine signaling 1 (SOCS1). Additionally, it was found that UL42 could promote the K6/K29-linked ubiquitination of p65. Finally, knockdown of SOCS1 attenuated the replication of PRV and led to a significant increase of the inflammatory cytokines. Taken together, our findings uncovered a novel mechanism that PRV-UL42 could upregulated SOCS1 to promote the ubiquitination degradation of p65 to prevent excessive inflammatory response during PRV infection.

KIAA0317 regulates SOCS1 stability to ameliorate colonic inflammation

Dysregulated cytokine signalling is a hallmark of inflammatory bowel diseases. Inflammatory responses of the colon are regulated by the suppressor of cytokine signalling (SOCS) proteins. SOCS1 is a key member of this family, and its function is critical in maintaining an appropriate inflammatory response through the JAK/STAT signalling pathway. Dysregulation of SOCS1 protein has been identified as a causal element in colonic inflammatory diseases. Despite this, it remains unclear how SOCS1 protein is regulated. Here, we identify that SOCS1 protein is targeted for degradation by the ubiquitin proteasome system, mediated by the E3 ubiquitin ligase KIAA0317 during experimental colonic inflammation. We characterize the mechanism of protein-protein interaction and ubiquitin conjugation to SOCS1 and demonstrate that the modulation of SOCS1 protein level leads to stark effects on JAK/STAT inflammatory signalling. Together, these results provide insight into the regulation of colonic inflammation through a new mechanism of ubiquitin-based control of SOCS1 protein.

Integrated analysis of multiple transcriptomic data identifies ST8SIA6‑AS1 and LINC01093 as potential biomarkers in HBV‑associated liver cancer

The mechanisms of long-non-coding RNAs (lncRNAs) in hepatitis B virus (HBV) infection-associated liver cancer remain largely unclear. Therefore, the aim of the present study was to investigate the regulatory mechanisms of lncRNAs in this disease. HBV-liver cancer related transcriptome expression profile data (GSE121248 and GSE55092) from the Gene Expression Omnibus database and survival prognosis information from The Cancer Genome Atlas (TCGA) database were obtained for analysis. The limma package was used to identify the overlapped differentially expressed RNAs (DERs), including DElncRNAs and DEmRNAs, in the GSE121248 and GSE55092 datasets. The screened optimized lncRNA signatures were used to develop a nomogram model based on the GSE121248 dataset, which was validated using the GSE55092 and TCGA datasets. A competitive endogenous RNA (ceRNA) network was constructed based on the screened prognosis-associated lncRNA signatures from TCGA dataset. In addition, the levels of specific lncRNAs were evaluated in HBV-infected human liver cancer tissues and cells, and Cell Counting Kit-8, ELISA and Transwell assays were performed to evaluate the effects of the lncRNAs in HBV-expressing liver cancer cells. A total of 535 overlapped DERs, including 30 DElncRNAs and 505 DEmRNAs, were identified in the GSE121248 and GSE55092 datasets. An optimized DElncRNA signature comprising 10 lncRNAs was used to establish a nomogram. ST8SIA6-AS1 and LINC01093 were identified as lncRNAs associated with HBV-liver cancer prognosis in TCGA dataset, and were applied to construct a ceRNA network. Reverse transcription-quantitative PCR analysis showed that ST8SIA6-AS1 was upregulated and LINC01093 was downregulated in HBV-infected human liver cancer tissues and HBV-expressing liver cancer cells compared with non-HBV-infected controls. ST8SIA6-AS1 knockdown and LINC01093 overexpression independently reduced the number of copies of HBV DNA, the levels of hepatitis B surface antigen and hepatitis B e antigen, as well as cell proliferation, migration and invasion. In summary, the present study identified ST8SIA6-AS1 and LINC01093 as two potential biomarkers that may be effective therapeutic targets for HBV-associated liver cancer.

Comprehensive analysis of the expression and prognosis for IQ motif-containing GTPase-activating proteins in hepatocellular carcinoma

BACKGROUND

IQ motif-containing GTPase-activating proteins (IQGAPs) are a group of scaffold proteins which have been identified to be involved in tumor initiation and progression in diverse types of cancer. Clinical studies and experimental evidence suggest that IQGAPs play an essential role in hepatocellular carcinoma (HCC) progression and alterations in their expression are closely related to patient prognosis. However, the different expression patterns and prognostic values of all three IQGAP isoforms in HCC have not yet been analyzed simultaneously.

METHODS

We analyzed the transcriptional and survival data of IQGAPs in HCC patients using Oncomine, UALCAN, Kaplan-Meier Plotter, cBioPortal, and GeneMANIA. We further examined tumor and adjacent normal tissues from 250 HCC patients using immunohistochemistry to assess the relationship between IQGAPs expression and clinicopathological features and validate the prognostic value of IQGAPs. In addition, we analyzed transcriptional changes of IQGAPs with regards to survival data in HCC patients from the TCGA-LIHC (liver hepatocellular carcinoma) cohort to validate our results.

RESULTS

We found that the expression levels of IQGAP1 and 3 were significantly elevated in HCC tissues than in normal liver tissues, whereas the expression level of IQGAP2 was decreased in the former than in the latter. The clinical data showed that positive IQGAP1 expression was associated with larger tumor size, advanced tumor-node-metastasis (TNM) stage, poor relapse-free survival (RFS), and overall survival (OS), and positive IQGAP3 expression was associated with poorer tumor differentiation, RFS, and OS. Conversely, positive IQGAP2 expression predicted less tumor numbers and microvascular invasion, as well as higher RFS and OS in these patients.

CONCLUSIONS

IQGAPs may serve as new prognostic biomarkers and potential targets for precision therapy in HCC.

Methylation-sensitive high-resolution melting analysis of the USP44 promoter can detect early-stage hepatocellular carcinoma in blood samples

Hepatocellular carcinoma (HCC) is dangerous cancer that often evades early detection because it is asymptomatic and an effective detection method is lacking. For people with chronic liver inflammation who are at high risk of developing HCC, a sensitive detection method for HCC is needed. In a meta-analysis of The Cancer Genome Atlas pan-cancer methylation database, we identified a CpG island in the USP44 promoter that is methylated specifically in HCC. We developed methylation-sensitive high-resolution melting (MS-HRM) analysis to measure the methylation levels of the USP promoter in cell-free DNA isolated from patients. Our MS-HRM assay correctly identified 40% of patients with early-stage HCC, whereas the α-fetoprotein test, which is currently used to detect HCC, correctly identified only 25% of early-stage HCC patients. These results demonstrate that USP44 MS-HRM analysis is suitable for HCC surveillance. [BMB Reports 2022; 55(11): 553-558].

Methylation-sensitive high-resolution melting analysis of the USP44 promoter can detect early-stage hepatocellular carcinoma in blood samples

Hepatocellular carcinoma (HCC) is dangerous cancer that often evades early detection because it is asymptomatic and an effective detection method is lacking. For people with chronic liver inflammation who are at high risk of developing HCC, a sensitive detection method for HCC is needed. In a meta-analysis of The Cancer Genome Atlas pan-cancer methylation database, we identified a CpG island in the USP44 promoter that is methylated specifically in HCC. We developed methylation-sensitive high-resolution melting (MS-HRM) analysis to measure the methylation levels of the USP promoter in cell-free DNA isolated from patients. Our MS-HRM assay correctly identified 40% of patients with early-stage HCC, whereas the α-fetoprotein test, which is currently used to detect HCC, correctly identified only 25% of early-stage HCC patients. These results demonstrate that USP44 MS-HRM analysis is suitable for HCC surveillance. [BMB Reports 2022; 55(11): 553-558].