A Potential Profibrogenic Role of Biliary Epithelium-Derived Cardiotrophin-1 in Pediatric Cholestatic Liver Disease

Karonudib is a promising anticancer therapy in hepatocellular carcinoma

Background:

Hepatocellular carcinoma (HCC) is the most common form of liver cancer and is generally caused by viral infections or consumption of mutagens, such as alcohol. While liver transplantation and hepatectomy is curative for some patients, many relapse into disease with few treatment options such as tyrosine kinase inhibitors, for example, sorafenib or lenvatinib. The need for novel systemic treatment approaches is urgent.

Methods:

MTH1 expression profile was first analyzed in a HCC database and MTH1 mRNA/protein level was determined in resected HCC and paired paracancerous tissues with polymerase chain reaction (PCR) and immunohistochemistry. HCC cancer cell lines were exposed in vitro to MTH1 inhibitors or depleted of MTH1 by siRNA. 8-oxoG was measured by the modified comet assay. The effect of MTH1 inhibition on tumor growth was explored in HCC xenograft in vivo models.

Results:

MTH1 protein level is elevated in HCC tissue compared with paracancerous liver tissue and indicates poor prognosis. The MTH1 inhibitor Karonudib (TH1579) and siRNA effectively introduce toxic oxidized nucleotides into DNA, 8-oxoG, and kill HCC cell lines in vitro. Furthermore, we demonstrate that HCC growth in a xenograft mouse model in vivo is efficiently suppressed by Karonudib.

Conclusion:

Altogether, these data suggest HCC relies on MTH1 for survival, which can be targeted and may open up a novel treatment option for HCC in the future.

Gene expression profile after knockdown of USP18 in Hepg2.2.15 cells

In our previous work, we found that the expression of ubiquitin-specific protease 18 (USP18), also known as UBP43, is associated with the efficiency of interferon alpha (IFN-α) treatment in patients with chronic hepatitis B (CHB). To elucidate the influence of USP18 on hepatitis B virus (HBV) replication and the mechanism of this activity, we silenced USP18 by introducing short hairpin RNA (shRNA) into Hepg2.2.15 cells. To identify the changed genes and pathways in Hepg2.2.15-shRNA-USP18 cells, we performed a microarray gene expression analysis to compare the Hepg2.2.15 stably expressing USP18-shRNA cells versus control cells using the Affymetrix Human Transcriptome Array (HTA) 2.0 microarrays. Microarray analysis indicated that genes involved in regulation of thyroid hormone signaling pathway, complement, and coagulation cascades, PERK-mediated unfolded protein response, and insulin-like growth factor-activated receptor activity were significantly altered after USP18 knockdown for 72 h. Furthermore, genes involved in hepatocyte proliferation, liver fibrosis, such as cell cycle regulatory gene CCND1, were also altered after USP18 knockdown in Hepg2.2.15 cells. In conclusion, USP18 is critical for regulating the replication of HBV in Hepg2.2.15 cells, which suggest that USP18 may be a candidate target for HBV treatment.

Hypoxia-inducible factor-2α promotes hepatocyte apoptosis during cholestasis

AIM

Hypoxia-inducible factor-2α (HIF-2α) has been reported to play an important role in a host of pathophysiological processes, including cellular survival. This study explores the role of HIF-2α in cholestasis-mediated hepatocyte apoptosis.

METHODS

Hypoxia-inducible factor-2α expression was measured by immunohistochemistry and confocal microscopy. Hepatic apoptosis was detected by terminal deoxynucleotidyl transferase-mediated dUTP-digoxigenin nick-end labeling. The cholestatic mouse model was treated with bile duct ligation. The c-myc, p53, and Bax protein levels were measured with Western blot analysis.

RESULTS

In pediatric and murine cholestatic liver tissues, HIF-2α protein was widely expressed in the nucleus of parenchymal cells as well as in stromal cells. Hepatocyte HIF-2α expression was significantly elevated at the early stage of pediatric cholestasis and decreased at the late stage. In both in vivo and in vitro murine studies, HIF-2α deletion could alleviate cholestasis-mediated hepatocyte apoptosis and regulate the expression of c-myc, p53, and Bax proteins.

CONCLUSION

These findings implied the contribution of HIF-2α to cholestasis-mediated hepatocyte apoptosis.

Evaluation of hepatic vascular endothelial injury during liver storage by molecular detection and targeted contrast-enhanced ultrasound imaging

We hypothesized that lack of the high-energy phosphates during liver storage may potentially cause persistent injury to the vascular endothelium. Biopsies were obtained from livers obtained from beating heart human donors, stored either in the standard storage solution, that is, University of Wisconsin solution (UWS) or Celsior, and examined for various markers related to progressive endothelial injury. The expression of P2Y1 receptor, the major signal transduction machinery for adenosine triphosphate/adenosine diphosphate, decreased in hepatic vascular endothelial cells over time. Despite unaltered endothelial nitric oxide synthase (eNOS) levels, serine1177-phosphorylated eNOS, the active form of eNOS, progressively decreased with time. The production of nitric oxide enzyme decreased with time when liver tissues were examined in vitro. This also coincided with decreased interaction of eNOS with actin nucleating proteins like myristoylated alanine-rich C kinase substrate and Rac1, which plays a role in modulating the cytoskeleton and helps position eNOS in a favorable cytosolic position for active enzymatic activity. Conversely, the interaction of eNOS with caveolin1 was significantly increased 6 H after ex vivo storage. Finally, we demonstrated by targeted contrast-enhanced ultrasound that membrane-bound vascular cell adhesion molecule-1 in the hepatic vascular endothelial cell increased after 6 H of ex vivo storage. Overall, the results of this study provide evidence of a progressive hepatic vascular endothelial injury during the ex vivo storage. This may be a causative factor for ischemic cholangiopathy and delayed graft function post liver transplantation. © 2015 IUBMB Life, 68(1):51-57, 2015.