AROS Is a Significant Biomarker for Tumor Aggressiveness in Non-cirrhotic Hepatocellular Carcinoma

NSD2 methylates AROS to promote SIRT1 activation and regulates fatty acid metabolism-mediated cancer radiotherapy

Fatty acid metabolism plays a critical role in both tumorigenesis and cancer radiotherapy. However, the regulatory mechanism of fatty acid metabolism has not been fully elucidated. NSD2, a histone methyltransferase that catalyzes di-methylation of histone H3 at lysine 36, has been shown to play an essential role in tumorigenesis and cancer progression. Here, we show that NSD2 promotes fatty acid oxidation (FAO) by methylating AROS (active regulator of SIRT1) at lysine 27, facilitating the physical interaction between AROS and SIRT1. The mutation of lysine 27 to arginine weakens the interaction between AROS and SIRT1 and impairs AROS-SIRT1-mediated FAO. Additionally, we examine the effect of NSD2 inhibition on radiotherapy efficacy and find an enhanced effectiveness of radiotherapy. Together, our findings identify a NSD2-dependent methylation regulation pattern of the AROS-SIRT1 axis, suggesting that NSD2 inhibition may be a potential adjunct for tumor radiotherapy.

Is there a role for liver transplantation in the treatment of hepatocellular carcinoma in non-cirrhotic liver?

Whether liver transplantation (LT) plays a role in the treatment of patients with hepatocellular carcinoma (HCC) in non-cirrhotic liver (NCL) is a matter of debate. The recommendations for LT in this setting are extremely fragile and less well-defined than for cirrhosis-associated HCC. All reports of LT for NCL-HCC revealed that long-term outcomes of these patients are poor, and these dismal figures are justified by the advanced tumor stage at the time of LT, suggesting the presence of systemic micrometastatic disease. The decision-making regarding LT for NCL-HCC is difficult, since specific selection criteria are scarce, and basically the potential candidates are those with unresectable only-liver tumor at admission, or unresectable intrahepatic recurrence post-resection. Besides the surgical aspects regarding the tumor resectability, other phenotypic and genetic characteristics of the tumor should be considered for the indication of LT in this scenario. The present minireview aims to discuss and analyze the last series of LT for NCL-HCC, in order to help clinicians in the decision-making process regarding the role of LT in NCL-HCC treatment.

Non-Cirrhotic Liver is Associated with Poor Prognosis of Hepatocellular Carcinoma: A Literature Review

Primary hepatocellular carcinoma (HCC) is the fifth most frequently reported malignancy, and it is also the second most common cause of cancer-related deaths worldwide. Although most HCC cases have been reported to develop from cirrhosis, accumulating data suggest that HCC is also closely related to non-cirrhotic chronic liver disease. Traditionally, HCC was thought to develop mostly from cirrhosis; however, an increasing number of reports have found that HCC can develop directly from inflammation without cirrhosis. The incidence of HCC in non-cirrhotic liver (HCC-NCL) is high, especially in developed countries. Studies have found that the most common cause of HCC-NCL is neglected fatty liver disease. This type of HCC has unique clinical characteristics and is closely related to metabolic disorders. Unfortunately, the prevention of HCC-NCL has not received enough attention worldwide, and there is also a lack of specific screening methods and clinical guidelines. This article mainly reviews the etiology, incidence, clinical characteristics, and screening markers of HCC-NCL to improve the understanding and prevention of this disease.

A hypothesis on paradoxical privileged portal vein metastasis of hepatocellular carcinoma. Can organ evolution shed light on patterns of human pathology, and vice versa?

Unlike other carcinomas, hepatocellular carcinoma (HCC) metastasizes to distant organs relatively rarely. In contrast, it routinely metastasizes to liver vasculature/liver, affecting portal veins 3-10 times more often than hepatic veins. This portal metastatic predominance is traditionally rationalized within the model of a reverse portal flow, due to accompanying liver cirrhosis. However, this intuitive model is not coherent with facts: 1) reverse portal flow occurs in fewer than 10% of cirrhotic patients, while portal metastasis occurs in 30-100% of HCC cases, and 2) portal vein prevalence of HCC metastasis is also characteristic of HCC in non-cirrhotic livers. Therefore, we must assume that the route for HCC metastatic dissemination is the same as for other carcinomas: systemic dissemination via the draining vessel, i.e., via the hepatic vein. In this light, portal prevalence versus hepatic vein of HCC metastasis appears as a puzzling pattern, particularly in cases when portal HCC metastases have appeared as the sole manifestation of HCC. Considering that other GI carcinomas (colorectal, pancreatic, gastric and small bowel) invariably disseminate via portal vein, but very rarely form portal metastasis, portal prevalence of HCC metastasis appears as a paradox. However, nature does not contradict itself; it is rather our wrong assumptions that create paradoxes. The 'portal paradox' becomes a logical event within the hypothesis that the formation of the unique portal venous system preceded the appearance of liver in evolution of chordates. The analysis suggests that the appearance of the portal venous system, supplying hormones and growth factors of pancreatic family, which includes insulin, glucagon, somatostatin, and pancreatic polypeptide (HGFPF) to midgut diverticulum in the early evolution of chordates (in an Amphioxus-like ancestral animal), promoted differentiation of enterocytes into hepatocytes and their further evolution to the liver of vertebrates. These promotional-dependent interactions are conserved in the vertebrate lineage. I hypothesize that selective homing and proliferation of malignant hepatocytes (i.e., HCC cells) in the portal vein environment are due to a uniquely high concentration of HGFPF in portal blood. HGFPF are also necessary for liver function and renewal and are significantly extracted by hepatocytes from passing blood, creating a concentration gradient of HGFPF between the portal blood and hepatic vein outflow, making post-liver vasculature and remote organs less favorable spaces for HCC growth. It also suggested that the portal vein environment (i.e., HGFPF) promotes the differentiation of more aggressive HCC clones from already-seeded portal metastases, explaining the worse outcome of HCC with the portal metastatic pattern. The analysis also offers new hypothesis on the phylogenetic origin of the hepatic diverticulum of cephalochordates, with certain implications for the modeling of the chordate phylogeny.

Clinicopathological and prognostic significance of PKM2 protein expression in cirrhotic hepatocellular carcinoma and non-cirrhotic hepatocellular carcinoma

Pyruvate kinase M2 (PKM2), a key protein in glucose and lipid metabolism, has been reported to be related to carcinogenesis in various malignancies. However, its roles in hepatocellular carcinoma with cirrhotic liver (CL) and hepatocellular carcinoma with non-cirrhoticliver (NCL) haves not been investigated. In our study western bloting, qRT-PCR and immunohistochemistry were performed to evaluate the clinical significance of PKM2 protein expression in CL and NCL. The results revealed that PKM2 protein expression was significantly higher in HCC tissues than in their adjacent non-tumour tissues. The high expression rates of PKM2 were more frequently noted in CL (45. 6%) than in NCL (31. 9%) tissues. High PKM2 expression in CL and NCL tissues was significantly associated with vascular invasion (P = 0.002 and P = 0.004, respectively) and intrahepatic metastasis (P < 0.001 and P = 0.019, respectively). Importantly, Kaplan-Meier survival analysis showed that the disease-specific survival (DSS) and recurrence-free survival (RFS) were lower in CL with high PKM2 expression than in NCL with high PKM2 expression (P = 0.003 and P = 0.003, respectively). Overall, high PKM2 expression was more frequently found in CL than in NCL, and PKM2 overexpression was associated with poor survival rates in patients with CL and NCL.