Characterization of hepatocellular carcinoma (HCC) in non-alcoholic fatty liver disease (NAFLD) patients without cirrhosis

Should we undertake surveillance for HCC in patients with NAFLD?

The pandemic of obesity and its related complications is rapidly changing the epidemiology of many types of cancer, including hepatocellular carcinoma (HCC). Non-alcoholic fatty liver disease (NAFLD) is becoming a major cause of HCC, with a steadily rising trend compared to viral or alcohol-induced chronic hepatitis. The much greater prevalence of the underlying liver disease in the general population and the chance of HCC occurrence in non-cirrhotic liver are the most worrisome aspects of HCC in NAFLD. Effective screening programmes are currently hampered by limited knowledge of the pathways of carcinogenesis and a lack of tools able to stratify the risk of HCC in the NAFLD population. Hence, poor surveillance has prevented the development of an adequate treatment for NAFLD-related HCC. Systemic and hepatic molecular mechanisms involved in hepatocarcinogenesis, as well as potential early markers of HCC are being extensively investigated. This review describes the current clinical impact of HCC in NAFLD and discusses the most important unmet needs for its effective management.

Serum magnesium concentration is independently associated with non-alcoholic fatty liver and non-alcoholic steatohepatitis

BACKGROUND

The pathogenesis of non-alcoholic fatty liver disease (NAFLD) has not been well recognized yet.

OBJECTIVE

This study aimed to investigate the association between serum magnesium concentration and NAFLD.

METHODS

Study participants were healthy individuals who had undergone liver biopsies between January 2012 and August 2015 as a routine pre-transplant check-up before living donor liver transplantation. Liver biopsy specimens were evaluated by an expert pathologist regarding presence of hepatic steatosis and steatohepatitis. Serum magnesium concentration was measured and compared in those with normal liver biopsy and those with steatosis and steatohepatitis.

RESULTS

A total of 226 individuals were included. Eighty-two individuals (36.2%) had hepatic steatosis and 22 (9.7%) individuals had steatohepatitis and steatosis in their liver histology. Lower serum magnesium concentration was independently associated with hepatic steatosis (OR: 0.059; 95% CI: 0.011-0.325, p = 0.001). Serum magnesium concentration was independently associated with steatohepatitis compared to those without steatohepatitis (1.80 ± 0.48 mg/dl and 2.18 ± 0.31 mg/dl) (OR: 0.11; 95% CI: 0.02-0.41, p = 0.001). Serum magnesium concentration was significantly lower in individuals with steatohepatitis (1.80 ± 0.48 mg/dl) compared to individuals without steatosis (2.23 ± 0.31 mg/dl, p < 0.001) and individuals with only steatosis (2.07 ± 0.29 mg/dl, p = 0.017).

CONCLUSION

Serum magnesium concentration is independently associated with hepatic steatosis and steatohepatitis in our study population.

NAFLD Related-HCC: The Relationship with Metabolic Disorders

Obesity increases death rates of all cancers including non-alcoholic fatty liver disease (NAFLD)-related hepatocellular carcinoma (NAFLD-HCC). NAFLD is considered as hepatic manifestation of metabolic syndrome and is a multi-system disease. Recent prevalence studies have intensively reported the association of obesity, metabolic risk factors and HCC incidence and mortality. Mechanistic studies suggested that immune response, PI3K/AKT/mTOR/PTEN pathway, mitochondrial dysfunction and genetic alterations are important mediators in the progression of NAFLD-HCC from metabolic disorder. In this book chapter, we attempt to collate current research on NAFLD-HCC that lead to our understandings on how metabolic disorders may intersect with cancer development. We also discussed the prevention options of NAFLD-HCC in view of obesity and metabolic disorder. These studies have extended our knowledge on the complicated mechanism of NAFLD and HCC, and provided the prevention options of NAFLD-HCC in patients with obesity and metabolic diseases.

Anti-tumor activity of KNTC2 siRNA in orthotopic tumor model mice of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is still one of the major causes of cancer-related death. Kinetochore-associated protein 2 (KNTC2) is specifically upregulated in tumor tissues of HCC patients and recognized as a potential candidate target for the treatment of HCC. However, the relationship between KNTC2 and in vivo tumor growth of HCC is not yet fully understood. Here we encapsulated KNTC2 siRNAs into a lipid nanoparticle (LNP) and investigated their knockdown activity, target engagement marker, anti-tumor activity and hepatotoxicity in an orthotopic HCC model mice of Hep3B-luc cells. Single i.v. administration of KNTC2 siRNA-LNP specifically suppressed the expression levels of both human KNTC2 mRNA and mouse Kntc2 mRNA in tumor tissues. Phosphorylation levels of histone H3 (HH3) at serine 10 in tumor tissues were increased by KNTC2 siRNA-LNP. Repeated administration of KNTC2 siRNA-LNP (twice a week) specifically inhibited the growth of tumor tissues without increasing the plasma AST and ALT levels. Their growth inhibitory activities were consistent with knockdown activities. These data strongly indicated that KNTC2 is a promising target for the treatment of HCC and that phosphorylated HH3 at serine 10 is one of the target engagement markers for KNTC2.

Type 2 diabetes mellitus and risk of hepatocellular carcinoma: spotlight on nonalcoholic fatty liver disease

The incidence of both type 2 diabetes mellitus (T2DM) and multiple cancer types are rapidly increasing worldwide. Several studies documented that T2DM is closely associated with an increased incidence of cancer. However, while some methodological considerations preclude a definitive association between T2DM and the risk of certain cancers, the relationship between T2DM and increased risk of incident hepatocellular carcinoma (HCC) remains significant even after adjustment for detection bias and reverse causation, indicating that such association is clinically reliable and robust. In addition, a number of observational studies also showed that T2DM is associated with higher mortality among persons with HCC. Some recent meta-analyses suggested that treatment with metformin may be associated with a lower risk of HCC, and may also beneficially influence HCC prognosis, whereas treatment with sulphonylureas or insulin seems to be related to a higher HCC risk. The underlying biological mechanisms linking T2DM and HCC are complex and difficult to elucidate, but the existence of close inter-connections among T2DM, obesity and nonalcoholic fatty liver disease (NAFLD) induces hepatic/systemic insulin resistance and causes the release of multiple pro-inflammatory cytokines, vasoactive factors and pro-oxidant molecules, which are all potentially implicated in the development and progression of HCC. In this clinical review, we discuss the epidemiological evidence linking T2DM to the risk of HCC. Moreover, we also briefly discuss the putative underlying mechanisms linking T2DM, NAFLD and HCC, and the potential effect of certain hypoglycemic agents on the risk of developing HCC.

Intermittent hypoxia is a proinflammatory stimulus resulting in IL-6 expression and M1 macrophage polarization

The biological factors that promote inflammation or nonalcoholic steatohepatitis (NASH) in the setting of nonalcoholic fatty liver disease remain incompletely understood. Clinical studies have demonstrated an association between obstructive sleep apnea (OSA) and both inflammation and fibrosis in NASH, but the mechanism has not been identified. In this study, we use in vitro modeling to examine the impact of intermittent hypoxia on the liver. Hepatocyte, stellate cell, and macrophage cell lines were exposed to intermittent or sustained hypoxia. Candidate genes associated with inflammation, fibrosis, and lipogenesis were analyzed. Circulating cytokines were assessed in human serum of patients with nonalcoholic fatty liver disease. Intermittent hypoxia results in significant induction of interleukin (IL)-6 expression in both hepatocytes and macrophages. The increase in IL-6 expression was independent of hypoxia inducible factor 1 induction but appeared to be in part related to antioxidant response element and nuclear factor kappa B activation. Mature microRNA 365 (miR-365) has been demonstrated to regulate IL-6 expression, and we found that miR-365 expression was decreased in the setting of intermittent hypoxia. Furthermore, macrophage cell lines showed polarization to an M1 but not M2 phenotype. Finally, we found a trend toward higher circulating levels of IL-6 in patients with OSA and NASH. Conclusion: Intermittent hypoxia acts as a potent proinflammatory stimulus, resulting in IL-6 induction and M1 macrophage polarization. Increased IL-6 expression may be due to both induction of antioxidant response element and nuclear factor kappa B as well as inhibition of miR-365 expression. Higher levels of IL-6 were observed in human samples of patients with OSA and NASH. These findings provide biological insight into mechanisms by which obstructive sleep apnea potentiates inflammation and fibrosis in patients with fatty liver disease. (Hepatology Communications 2017;1:326-337).

Hepatocellular carcinoma in non-alcoholic steatohepatitis: Current knowledge and implications for management

With the prevalence of hepatitis C virus expected to decline, the proportion of hepatocellular carcinoma (HCC) related to non-alcoholic steatohepatitis (NASH) is anticipated to increase exponentially due to the growing epidemic of obesity and diabetes. The annual incidence rate of developing HCC in patients with NASH-related cirrhosis is not clearly understood with rates ranging from 2.6%-12.8%. While multiple new mechanisms have been implicated in the development of HCC in NASH; further prospective long-term studies are needed to validate these findings. Recent evidence has shown a significant proportion of patients with non-alcoholic fatty liver disease and NASH progress to HCC in the absence of cirrhosis. Liver resection and transplantation represent curative therapeutic options in select NASH-related HCC patients but have placed a significant burden to our healthcare resources and utilization. Currently NASH-related HCC is the fastest growing indication for liver transplant in HCC candidates. Increased efforts to implement effective screening and preventative strategies, particularly in non-cirrhotic NASH patients, are needed to reduce the future impact imposed by NASH-related HCC.

Peretinoin as an adjuvant therapy for hepatocellular carcinoma

The current curative treatment modalities for hepatocellular carcinoma (HCC) are unfortunately fraught with high rates of HCC recurrence. Hence there is a need to prevent or reduce HCC recurrence after initial curative therapy. Peretinoin is a synthetic oral retinoid showing significant reduction in the incidence of recurrent or new HCC in patients who had received curative HCC therapy. Areas covered: Peretinoin is analysed against the background of molecular pathogenesis of the different causes of HCC. Publications related to peretinoin since 1996 are reviewed, covering clinical characteristics, safety and tolerance profile as well as the current status of clinical development. Expert commentary: Early phase studies are promising but we need to await the results of the ongoing phase III study of peretinoin in hepatitis C related HCC. Long term impact of peretinoin may be diminished by the foreseeable near eradication of hepatitis C by the direct acting antivirals.

Hepatocellular Carcinoma in Nonalcoholic Fatty Liver Disease

Our objective was to study nonalcoholic fatty liver disease (NAFLD) as a relevant risk factor associated with hepatocellular carcinoma (HCC) in patients with and without cirrhosis. HCC is a common cancer worldwide that predominantly involves patients with hepatic cirrhosis. HCC has recently been linked to NAFLD, the hepatic manifestation of obesity and related metabolic disorders. This association is alarming due to the high prevalence of NAFLD globally, which may contribute to the rising incidence of HCC.

A 31-year-old female with a history of dyslipidemia, hypertension, and diabetes mellitus presented with abdominal pain that persisted for six months. The pain was associated with gastrointestinal symptoms and weight loss. She was drug-free and a nonalcoholic and a nonsmoker. The physical examination was unremarkable. The abdominal exam showed a soft and non-tender abdomen, with no organomegaly or ascites. The laboratory evaluation was unremarkable. The imaging studies showed a hypodense lesion in the right hepatic lobe with strong arterial enhancement. Subsequently, the patient underwent a liver biopsy. The histopathology results were consistent with HCC.

The patient underwent an uneventful segment VI liver resection and tumor-free margins were achieved. In our patient, NAFLD was designated as an independent etiology for HCC, without cirrhosis. Our patient recovered well and has been disease free for over a year. HCC may complicate non-cirrhotic NAFLD with mild or absent fibrosis, greatly expanding the population potentially at higher risk of HCC. These results provide new targets for surveillance, prevention, early recognition, and effective treatment of HCC associated with NAFLD.

Loss of c-Met signaling sensitizes hepatocytes to lipotoxicity and induces cholestatic liver damage by aggravating oxidative stress

Recent studies confirmed a critical importance of c-Met signaling for liver regeneration by modulating redox balance. Here we used liver-specific conditional knockout mice (MetKO) and a nutritional model of hepatic steatosis to address the role of c-Met in cholesterol-mediated liver toxicity. Liver injury was assessed by histopathology and plasma enzymes levels. Global transcriptomic changes were examined by gene expression microarray, and key molecules involved in liver damage and lipid homeostasis were evaluated by Western blotting. Loss of c-Met signaling amplified the extent of liver injury in MetKO mice fed with high-cholesterol diet for 30days as evidenced by upregulation of liver enzymes and increased synthesis of total bile acids, aggravated inflammatory response and enhanced intrahepatic lipid deposition. Global transcriptomic changes confirmed the enrichment of networks involved in steatosis and cholestasis. In addition, signaling pathways related to glutathione and lipid metabolism, oxidative stress and mitochondria dysfunction were significantly affected by the loss of c-Met function. Mechanistically, exacerbation of oxidative stress in MetKO livers was corroborated by increased lipid and protein oxidation. Western blot analysis further revealed suppression of Erk, NF-kB and Nrf2 survival pathways and downstream target genes (e.g. cyclin D1, SOD1, gamma-GCS), as well as up-regulation of proapoptotic signaling (e.g. p53, caspase 3). Consistent with the observed steatotic and cholestatic phenotype, nuclear receptors RAR, RXR showed increased activation while expression levels of CAR, FXR and PPAR-alpha were decreased in MetKO. Collectively, our data provide evidence for the critical involvement of c-Met signaling in cholesterol and bile acids toxicity.