Objective Hepatitis B virus X protein (HBx) is a pivotal factor for HBV-induced hepatitis. Herein, we sought to investigate HBx-mediated NLR pyrin domain containing 3 (NLRP3) inflammasome activation and pyroptosis under oxidative stress. Methods The effect of HBx on the NLRP3 inflammasome was analyzed by enzyme-linked immunosorbent assays, quantitative reverse transcription-polymerase chain reaction, western blotting, and immunofluorescence in hepatic HL7702 cells. Pyroptosis was evaluated by western blotting, lactate dehydrogenase release, propidium iodide staining, and transmission electron microscopy. NLRP3 expression in the inflammasome from liver tissues was assessed by immunohistochemistry. Results In hydrogen peroxide (H 2 O 2)-stimulated HL7702 cells, HBx triggered the release of pro-inflammatory mediators apoptosis-associated speck-like protein containing a CARD (ASC), interleukin (IL)-1β, IL-18, and high-mobility group box 1 (HMGB1); activated NLRP3; and initiated pro-inflammatory cell death (pyroptosis). HBx localized to the mitochondria, where it induced mitochondrial damage and production of mitochondrial reactive oxygen species (mitoROS). Treatment of HL7702 cells with a mitoROS scavenger attenuated HBx-induced NLRP3 activation and pyroptosis. Expression levels of NLRP3, ASC, and IL-1β in liver tissues from patients were positively correlated with HBV DNA concentration. Conclusions The NLRP3 inflammasome was activated by elevated mitoROS levels and mediated HBx-induced liver inflammation and hepatocellular pyroptosis under H 2 O 2-stress conditions.
Hepatocellular Carcinoma (HCC) is the fifth most prevalent cancer worldwide. Specially, Hepatitis B viurs X protein (HBx) is a leading factor in the progression of Hepatitis B viurs-related HCC. Nutrient-deprived tumor microenvironment also contributes to tumor development. However, the role of HBx in nutrient-deprived HCC has received little investigation. Here, we show that HBx elevates PINK1-Parkin mediating mitophagy in starvation. HBx not only increases the PINK1/Parkin gene expression but also accelerates Parkin recruitment to partial mitochondria. Further analysis indicates that, HBx either promotes mitochondrial unfolded protein response, with remarkable mitochondrial LONP1 increases, or reduces LONP1 expression in cytosol inducing LONP1-Parkin pathway, both consequently enhancing mitophagy. Moreover, the enhanced mitophagy lowers mitochondrial apoptosis in starved hepatoma cells, and Bax is implied in the machinery. In addition, we define differential centrifuge, 3000 g or 12,000 g to pellet mitochondria, as an effective method to obtain distinct mitochondria. In collect, HBx regulates diverse aspects of LONP1 and Parkin, enhancing mitophagy in starvation. This study may shed new insights into the machinery development of hepatocellular carcinoma.
Chronic hepatitis B virus (HBV) infection is a leading cause of liver cirrhosis and cancer. Among the pathogenic factors of HBV, HBV X protein (HBx) is attracting increased attention. Although it is documented that HBx is a multifunctional regulator that modulates cell inflammation and apoptosis, the exact mechanism remains controversial. In the present study, we explored the effect of HBx on oxidative stress-induced apoptosis in normal liver cell line, HL-7702. Our results showed that the existence of HBx affected mitochondrial biogenesis by modulating the opening of the mitochondrial permeability transition pore (MPTP). Notably, this phenomenon was associated with a pronounced translocation of Bax from the cytosol to the mitochondria during the period of exposure to oxidative stress with a release of cytochrome c and activation of cleaved caspase-3 and PARP. Moreover, MPTP blockage with cyclosporin A prevented the translocation of Bax, and inhibited oxidative stress-induced apoptotic killing in the HBx-expressing HL-7702 cells. Our findings suggest that HBx exhibits pro-apoptotic effects upon normal liver cells following exposure to oxidative stress by modulating the MPTP gateway.
BackgroundGastric cancer (GC) has a high morbidity and mortality rate, with peritoneal metastasis (PM) identified as the main site of metastasis. Our previous study found that FNDC1 has a higher frequency of mutations in patients with PM by high-throughput sequencing assay, suggesting that it may be associated with GC invasion and PM, however the specific mechanism remains unclear.MethodsFirst, the correlation between FNDC1 and PM and prognosis of GC was clarified by bioinformatics and clinicopathological analysis. Next, the effect of FNDC1 expression on the invasion and metastasis ability of GC was investigated in vivo and in vitro. Finally, the signaling pathways involved in the regulation of FNDC1 were explored.ResultsFNDC1 was highly expressed in GC and was associated with PM and poor prognosis. FNDC1 was also associated with epithelial-mesenchymal transition (EMT) in GC cells. Through in vivo and in vitro experiments, it was clarified that knockdown of FNDC1 could inhibit the proliferation, invasion, and migration of GC cells. In addition, it was elucidated that FNDC1 promotes EMT through the Wnt/β-catenin signaling pathway.ConclusionFNDC1 may be associated with the invasion of GC and PM after surgery. FNDC1 was highly expressed in GC tissues and cell lines, while significantly associated with poor DFS and OS in GC patients. Both univariate and multivariate analyses suggested that the expression of FNDC1 was an independent factor for GC. Knockdown of FNDC1 also significantly inhibited the proliferation, migration, and activity of GC cells. FNDC1 may promote EMT in GC cells through the regulation of Wnt/β-catenin signaling pathway. FNDC1 has the potential to be used as a predictor of PM and may also be studied in depth as a therapeutic target for GC, which has potential clinical utility and is worthy of further validation.
Hepatitis B virus X protein (HBx) has been termed a viral oncoprotein, and is involved in the initiation and progression of hepatocellular carcinoma (HCC). Cyclooxygenase‑2 (COX‑2) and β‑catenin have been attributed to the oncogenic activity of HBx in HBV‑associated HCC. The present study aimed to determine whether there is crosstalk between COX‑2 and the Wnt/β‑catenin signaling pathway during HL‑7702‑HBx cell proliferation, and to investigate the associated underlying molecular mechanism. In the present study, cell proliferation assay, colony formation assay and flow cytometric analysis were used to detect the proliferative ability of cells. Reverse transcription‑quantitative polymerase chain reaction and western blotting were performed to examine the mRNA and protein expression of COX‑2, β‑catenin, cyclin‑D1 and c‑myc. The results demonstrated that HL‑7702‑HBx exhibited increased cell proliferation, higher colony formation efficiency and a shortened G1 period of the cell cycle. In addition, the mRNA and protein expression levels of COX‑2 were increased, and this was associated with HL‑7702‑HBx cell growth. Furthermore, the expression of β‑catenin and its target genes, cyclin‑D1 and c‑myc proto‑oncogene protein, was upregulated by HBx via COX‑2. Finally, HBx promoted HL‑7702 cell proliferation through the Wnt/β‑catenin signaling pathway. In conclusion, the primary finding of the present study was that HBx may promote HL‑7702 cell proliferation via the COX‑2/Wnt/β‑catenin pathway. Thus, it may be helpful to further investigate the molecular mechanism of HBV‑associated hepatocellular carcinoma.
Background
Hepatocellular carcinoma (HCC), with Hepatitis B viurs X protein (HBx) as one of the main etiology, harbors various metabolic phenotypes for distinct nutrient availability inside solid tumors. Trichostatin A is a histone inhibitor, supposed to inhibit cancer development. However, the role of TSA in tumor cells with metabolic stress has received little investigation.
Methods
We built a HBx-overexpression hepatoma cell model with HBx plasmids transfection, and EBSS was applied in nutrient-deprived cell model. Through western blot, Q-PCR and immunoprecipitation, we further explored the molecular mechanism of TSA-related anti-cancer function.
Results
In our study here, we found that TSA inhibited HBx-enhanced metastasis in metabolic stress, and demonstrated that Sirtuin 3 (SIRT3), one of tumor suppressors in HCC, played a role in TSA-related anti-cancer function in metabolic stress, and TSA promoted SIRT3 transcription.
Conclusions
We suggest that TSA alleviated specific subset of HCC, the HBx-induced HCC in metabolic stress, through promoting SIRT3 transcription, suggesting that TSA is a potential drug for HCC treatment.
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