Alteration in gene expression profile by full-length hepatitis B virus genome

miR‑4730 suppresses the progression of liver cancer by targeting the high mobility group A1 pathway

As liver cancer (LC) is the sixth most commonly diagnosed malignancy, it is necessary to elucidate the molecular mechanisms responsible for LC progression. MicroRNAs (miRNAs/miRs) play crucial roles in tumor progression by regulating target gene expression. The present study assessed miRNA-4730 expression and function in LC. The effects of miR-4730 overexpression were examined in LC cell lines, and the target genes of miR-4730 were evaluated using microarray analysis and TargetScan data. In addition, the association between miR-4730 expression in tissue samples and the prognosis of 70 patients with LC was evaluated. miR-4730 expression was suppressed in LC tissues and cell lines. miR-4730 overexpression suppressed cell proliferation and cell cycle progression and promoted apoptosis. High mobility group A1 (HMGA1) was revealed as the direct target of miR-4730 using luciferase reporter assay, and the inhibition of downstream integrin-linked kinase (ILK) expression and Akt or glycogen synthase kinase 3β (GSK3β) phosphorylation was confirmed. The lower expression of miR-4730 in tissue samples was significantly associated with a worse recurrence-free survival of patients with LC. On the whole, miR-4730 suppressed tumor progression by directly targeting HMGA1 and inhibiting the ILK/Akt/GSK3β pathway. miR-4730 thus has potential for use as a prognostic marker and may prove to be a therapeutic target for miRNA-based therapies.

High-Mobility Group AT-Hook 1 Served as a Prognosis Biomarker and Associated with Immune Infiltrate in Hepatocellular Carcinoma

BACKGROUND

The protein high-mobility group AT-hook 1 (HMGA1) has been demonstrated that modulated cellular proliferation, invasion, and apoptosis with a poor prognosis in miscellaneous carcinomas. However, the mechanism of circumstantial carcinogenesis and association with the immune microenvironment of HMGA1 in hepatocellular carcinoma (HCC) had not been extensively explored.

METHODS

The gene expression, clinicopathological correlation, and prognosis analysis were performed in the data obtained from TCGA. The results were further validated by ICGC and GEO database and external validation cohort from Guangxi. The HMGA1 protein expression was further examined in the HPA database. Biological function analyses were conducted by GSEA, STRING database, and Coexpedia online tool. Using TIMER and CIBERSORT method, the relationship between immune infiltrate and HMGA1 was investigated.

RESULTS

In HCC, HMGA1 had much higher transcriptional and proteomic expression than in corresponding paraneoplastic tissue. Patients with high HMGA1 expression had a poor prognosis and unpromising clinicopathological features. High HMGA1 expression was closely related to the cell cycle, tumorigenesis, substance metabolism, and immune processes by regulating complex signaling pathways. Notably, HMGA1 may be associated with TP53 mutational carcinogenesis. Moreover, increased HMGA1 expression may lead to an increase in immune infiltration and a decrease in tumor purity in HCC. CIBERSORT analysis elucidated that the amount of B cell naive, B cell memory, T cells gamma delta, macrophages M2, and mast cell resting decreased when HMGA1 expression was high, whereas T cells follicular helper, macrophages M0, and Dendritic cells resting increased.

CONCLUSION

In conclusions, HMGA1 is a potent prognostic biomarker and a sign of immune infiltration in HCC, which may be a potential immunotherapy target for HCC.

The regulation of proteins associated with the cytoskeleton by hepatitis B virus X protein during hepatocarcinogenesis

Hepatocellular carcinoma (HCC) is a major malignant disease worldwide, and chronic hepatitis B virus (HBV) infection is one of the primary causes for this type of cancer. Hepatitis B virus X protein (HBx) is a non-structural protein encoded by the viral genome that has significant effects on the pathogenesis of HCC. With the development of high-throughput assays and technologies, the abnormal HBx-induced expression of certain cellular proteins with assorted biological functions has been investigated. These target proteins identified by various methods include specific proteins associated with the cellular cytoskeleton, which contribute to HBx-induced hepatocarcinogenesis. In addition, the cytoskeletal proteins deregulated by HBx are involved in cell morphogenesis, adhesion, migration and proliferation. This review aims to summarize the current understanding of the expression profiles of HBx-associated cytoskeletal proteins, as well as their complex functions and underlying mechanisms in hepatocarcinogenesis. Considering that the potential therapeutics for various types of tumors may function through the stabilization of cytoskeletal proteins in order to restrict cellular movement and limit intracellular processes, clarifying the mechanisms underlying protein-associated cytoskeleton dysregulation by HBx may provide novel possibilities and potent therapeutic targets for HBV-associated HCC.

Gene-expression profiles of a hepatitis B small surface antigen-secreting cell line reveal upregulation of lymphoid enhancer-binding factor 1

The genome of hepatitis B virus (HBV) consists of four open reading frames, encoding the envelope proteins (Pre-S/S), the core proteins (Pre-C/C), the polymerase (P) and the transactivating X protein (X). In the sera of HBV-infected patients, hepatitis B surface antigen (HBsAg) particles without the viral genome can outnumber virions by more than 1000-fold. To analyse the interactions between HBsAg and host cells, global gene-expression profiles of a small HBsAg (SHBs)-secreting stable cell line (HepG2-S-G2) and its counterpart control cell line (HepG2-Neo-F4) were compared. Marked upregulation of lymphoid enhancer-binding factor 1 (LEF-1), a transcription factor in the Wnt pathway, was found in SHBs-expressing cells and was confirmed by interference experiments with small interfering RNA. However, compared with the control cells, HepG2-S-G2 did not show higher proliferative competence in culture or increased tumorigenesis in nude mice. A possible mechanism to explain the discrepancy between the upregulation of LEF-1 and the lack of increased tumorigenesis is SHBs expression resulting in altered expression and distribution of LEF-1 protein in cell compartments and upregulation of LEF-1 isoforms that could suppress, rather than enhance, the Wnt pathway.

Hepatitis B virus replication causes oxidative stress in HepAD38 liver cells

We used human hepatoma HepAD38 cells, in which HBV production is under the control of a tetracycline-regulated promotor, to investigate changes induced in the host cell by HBV replication that could contribute to malignant transformation. Parameters of oxidative stress (malondialdehyde, glutathione) and cell proliferation were determined at different times after induction (0-96 h). In HBV-producing cells, the redox status peaked at 72 h. cDNA micro array analysis at 72 h post induction revealed 3 groups of genes that were up-regulated by HBV: (i) heat shock proteins, (ii) oxidative and metabolic stress and (iii) growth and apoptosis related genes. Continuous HBV production did not accelerate karyotypic changes in cells cultured for 4 months (18 passages).

IN CONCLUSION

HBV replication modulates host gene expression and induces oxidative stress. In this HepAD38 model early events (0-4 days) in the host cell after induction of HBV replication can be studied under strictly defined conditions.