TERT elevation by AR via integrated HBV and point mutation at TERT promoter region was identified as a new mechanism for the male dominance of HBV-related HCCs. Telomerase and AR thus become new targets for intervention of HCC. This article is protected by copyright. All rights reserved.

BaCKgRoUND aND aIMS: Early recurrence of hepatocellular carcinoma (HCC) after surgical resection compromises patient survival. Timely detection of HCC recurrence and its clonality is required to implement salvage therapies appropriately. This study examined the feasibility of virus-host chimera DNA (vh-DNA), generated from junctions of hepatitis B virus (HBV) integration in the HCC chromosome, as a circulating biomarker for this clinical setting. appRoaCH aND ReSUltS: HBV integration in 50 patients with HBV-related HCC was determined by the Hybridization capture-based next-generation sequencing (NGS) platform. For individual HCC, the vh-DNA was quantified by specific droplet digital PCR (ddPCR) assay in plasma samples collected before and 2 months after surgery. HBV integrations were identified in 44 out of 50 patients with HBV-related HCC. Tumor-specific ddPCR was developed to measure the corresponding vh-DNA copy number in baseline plasma from each patient immediately before surgery. vh-DNA was detected in 43 patients (97.7%), and the levels correlated with the tumor sizes (detection limit at 1.5 cm). Among the plasma collected at 2 months after surgery, 10 cases (23.3%) still contained the same signature vh-DNA detected at baseline, indicating the presence of residual tumor cells. Nine of them (90%) experienced HCC recurrence within 1 year, supporting vh-DNA as an independent risk factor in predicting early recurrence. Analysis of circulating vh-DNA at recurrence further helped identify the clonal origin. A total of 81.8% of recurrences came from original HCC clones sharing the same plasma vh-DNA, whereas 18.2% were from de novo HCC. CoNClUSIoNS: vh-DNA was shown to be a circulating biomarker for detecting the tumor load in majority of patients with HBV-related HCC and aided in monitoring residual tumor and recurrence clonality after tumor resection. (Hepatology 2020;72:2063-2076). S urgical resection has been recommended for earlystage hepatocellular carcinoma (HCC) when the liver function is well preserved. (1) Although the clinical outcome is improved after resection, these patients still confront high risk for recurrent HCC, at a rate of about 40%-50% within 2 years. (2) Recurrence after resection, especially those that recur within 1 year, significantly decreases the survival of patients with HCC. Early recurrence after tumor resection, possibly originating from residual HCC, thus compromises the long-term prognosis.

The estrogen pathway has long been implicated as a tumor protector in female hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). Our previous study identified that estrogen receptor alpha (ERa) protein is downregulated in 60% of female HCC cases, via a miR-18a elevation mediated suppression of ERa translation. This study aims to delineate the mechanism underlying the upregulation of miR-18a in female HCC. The analysis of 77 female HCC specimens revealed that miR-18a levels were associated with pre-miR-18a rather than pri-miR-18a levels, suggesting an enhanced processing of pri-to pre-miR-18a. Among a panel of factors involved in microRNA processing, p53 was identified as a novel regulator for miR-18a maturation process. Knockdown of p53 by si-RNA decreased the level of miR-18a, whereas overexpression of either wild-type or mutant p53 increased its level. The association between the elevation of miR-18a and the accumulation of p53, mainly caused by somatic mutations, was confirmed in the clinical specimens of HBV-related female HCC. By analyzing the association with clinicopathological features, activation of this p53/miR-18a pathway mainly occurs in younger or noncirrhosis female HCC patients and associated with a trend of worse overall survival. Therefore, this study demonstrated a novel function of elevated/mutant p53 in regulating the amount of ERa protein through its promoting the biogenesis of miR-18a, which could lead to decrease the tumor-protective function of the estrogen pathway in female hepatocarcinogenesis.Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide and its strong association with hepatitis B virus (HBV) and hepatitis C virus (HCV) infection is well known.1 Among the nonviral risk factors, the male sex factor has long been considered as a major risk factor of HCC, 2,3 as the incidence of HCC in male patients is 2-to 11-fold higher than that observed in females; this is even more evident in HBV-related HCC. 4 The sex hormones, including both the androgen and estrogen axes, are involved in the regulation of this gender difference in HCC. 4,5 The serial cohort studies performed by Yu et al. showed that an elevation in the activity of the androgen pathway was associated with higher HCC risk in male HBV carriers, whereas an elevation in the activity of the estrogen pathway was associated with lower HCC risk in female HBV carriers. 6 These results suggested opposite roles of the androgen and estrogen pathways in hepatocarcinogenesis, which might contribute to the gender difference of HCC.At the molecular level, recent studies have identified several mechanisms underlying the function of androgen and estrogen in the hepatocarcinogenic process. Regarding the androgen pathway, we found a positive regulatory loop between the viral Hepatitis B virus X protein and ligandactivated androgen receptor (AR) transcriptional activation in HBV-infected hepatocytes. This loop leads to persistently elevated AR activity and increased HBV mRNA transcription, which contribute to the ...

A growing list of microRNAs (miRNAs) show aberrant expression patterns in hepatocellular carcinoma (HCC), but the regulatory mechanisms largely remain unclear. RNA editing catalyzed by members of the adenosine deaminase acting on the RNA (ADAR) family could target the miRNA precursors and affect the biogenesis process. Therefore, we investigate whether RNA editing could be one mechanism contributing to the deregulation of specific miRNAs in HCC. By overexpression of individual ADARs in hepatoma cells, RNA editing on the precursors of 16 miRNAs frequently deregulated in HCC was screened by a sensitive high-resolution melting platform. The results identified RNA precursors of miR-214 and miR-122 as potential targets edited by ADAR2. A subset of HCC showing elevated ADAR2 verified the major editings identified in ARAR2 overexpressed hepatoma cells, either with A-to-I or U-to-C changes. The unusual U-to-C editing at specific residues was demonstrated as being attributed to the A-to-I editing on the RNA transcripts complementary to the pri-miRNAs. The editing event caused a decrease of the RNA transcript complementary to pri-miR-214, which led to the decrease of pri-miR-214 and miR-214 and resulted in the increased protein level of its novel target gene Rab15. In conclusion, the current study discovered ADAR2-mediated editing of the complementary antisense transcripts as a novel mechanism for regulating the biogenesis of specific miRNAs during hepatocarcinogenesis.

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4090 Background: About one-third of patients suffer tumor recurrence within the first year after surgical resection of HCC. Early recurrence compromised their overall survival. Timing detection of HCC recurrence and its clonality is required to implement therapeutic trials appropriately. This study examined the virus-host chimera DNA (vh-chimera DNA), generated from junctions of HBV integration in HCC chromosome and released into blood, as a potential circulating biomarker for this clinical setting. Methods: We established a capture-next generation sequencing (NGS) platform to identify the HBV integrations in 50 resected HBV-related HCC. For individual HCC, the major clonal HBV integration sites were chosen to design specific primers for droplet digital PCR (ddPCR) to detect and quantify the vh-chimera DNA in plasma samples, collected either just before surgery or two months after surgery. Levels of vh-chimera DNA were then correlated with baseline HCC size or recurrence in one-year follow up. Results: We succeeded in detecting HBV integrations in the HCC from 44 out of 50 HBV-related HCC patients (88%). The copy number of vh-chimera DNA in plasma at surgery from 42 patients correlated with tumor sizes, with the detection limit at 1.5-2 cm. Among the plasma collected 2 months after surgery, 26.2% of samples contained the same HCC signature vh-chimera DNA as baseline plasma, indicating a possible residual tumor. Consistently, 81.8% of them suffered HCC recurrence within one year. The signature vh-DNA in the plasma suggested the majority of recurrences coming from the original HCC clones, whereas 2 from de novo ones. Conclusions: This study supported vh-chimera DNA as a new circulation marker for detecting the existence of most HBV-related HCC. This new biomarker may complement AFP to help detect residual or recurrent HCC and their clonality after curative therapies.

Since the D614G substitution in the spike (S) of SARS-CoV-2 emerged, the variant strain underwent rapid expansion to become the most abundant strain worldwide. Therefore, this substitution may provide an advantage of viral spreading. To explore the mechanism, we analyzed 18 viral isolates containing S proteins with either G614 or D614. Both the virus titer and syncytial phenotype were significantly increased in S-G614 than in S-D614 isolates. We further showed increased cleavage of S at the furin substrate site, a key event that promotes syncytium, in S-G614 isolates. These functions of the D614G substitution were validated in cells expressing S protein. The effect on syncytium was abolished by furin inhibitor treatment and mutation of the furin-cleavage site, suggesting its dependence on cleavage by furin. Our study provides a mechanistic explanation for the increased transmissibility of S-G614 containing SARS-CoV-2 through enhanced furin-mediated S cleavage, which increases membrane fusion and virus infectivity.