Roles of p53 in extrinsic factor-induced liver carcinogenesis

H-ras-targeted genetic therapy remarkably surpassed docetaxel treatment in inhibiting chemically induced hepatic tumors in rats

AIMS

Hepatocellular carcinoma (HCC) is still a leading cause of cancer-related death worldwide. But its chemotherapeutic options are far from expectation. We here compared H-ras targeted genetic therapy to a commercial docetaxel formulation (DXT) in inhibiting HCC in rats.

MAIN METHODS

After the physicochemical characterization of phosphorothioate-antisense oligomer (PS-ASO) against H-ras mutated gene, the PS-ASO-mediated in vitro hemolysis, in vivo hepatic uptake, its pharmacokinetic profile, tissue distribution in some highly perfused organs, its effect in normal rats, antineoplastic efficacy in carcinogen-induced HCC in rats were evaluated and compared against DXT treatment. Mutated H-ras expression by in situ hybridization, hep-par-I, CK-7, CD-15, p53 expression patterns by immunohistochemical methods, scanning electron microscopic evaluation of hepatic architecture, various hepatic marker enzyme levels and caspase-3/9 apoptotic enzyme activities were also carried out in the experimental rats.

KEY FINDINGS

PS-ASO showed low in vitro hemolysis (<3 %), and had a sustained PS-ASO blood residence time in vivo compared to DTX, with a time-dependent hepatic uptake. It showed no toxic manifestations in normal rats. PS-ASO distribution was although initially less in the lung than liver and kidney, but at 8 h it accumulated more in lung than kidney. Antineoplastic potential of PS-ASO (treated for 6 weeks) excelled in inhibiting chemically induced tumorigenesis compared to DTX in rats, by inhibiting H-ras gene expression, some immonohistochemical modulations, and inducing caspase-3/9-mediated apoptosis. It prevented HCC-mediated lung metastatic tumor in the experimental rats.

SIGNIFICANCE

PS-ASO genetic therapy showed potential to inhibit HCC far more effectively than DXT in rats.

The Loss of an Orphan Nuclear Receptor NR2E3 Augments Wnt/β-catenin Signaling via Epigenetic Dysregulation that Enhances Sp1-β catenin-p300 Interactions in Hepatocellular Carcinoma

The orphan nuclear receptor NR2E3 (Nuclear receptor subfamily 2 group E, Member 3) is an epigenetic player that modulates chromatin accessibility to activate p53 during liver injury. Nonetheless, a precise tumor suppressive and epigenetic role of NR2E3 in hepatocellular carcinoma (HCC) development remains unclear. HCC patients expressing low NR2E3 exhibit unfavorable clinical outcomes, aligning with heightened activation of the Wnt/β-catenin signaling pathway. The murine HCC models utilizing NR2E3 knockout mice consistently exhibits accelerated liver tumor formation accompanied by enhanced activation of Wnt/β-catenin signaling pathway and inactivation of p53 signaling. At cellular level, the loss of NR2E3 increases the acquisition of aggressive cancer cell phenotype and tumorigenicity and upregulates key genes in the WNT/β-catenin pathway with increased chromatin accessibility. This event is mediated through increased formation of active transcription complex involving Sp1, β-catenin, and p300, a histone acetyltransferase, on the promoters of target genes. These findings demonstrate that the loss of NR2E3 activates Wnt/β-catenin signaling at cellular and organism levels and this dysregulation is associated with aggressive HCC development and poor clinical outcomes. In summary, NR2E3 is a novel tumor suppressor with a significant prognostic value, maintaining epigenetic homeostasis to suppress the Wnt/β-catenin signaling pathway that promotes HCC development.

Significance of 8-OHdG Expression as a Predictor of Survival in Colorectal Cancer

The incidence of colorectal cancer (CRC) is increasing worldwide. 8-hydroxy-2'-deoxyguanosine (8-OHdG), one of the most prevalent DNA alterations, is known to be upregulated in several carcinomas; however, 8-OHdG has not been used to predict the prognosis of patients with CRC. We aimed to determine 8-OHdG levels in patients with CRC using immunohistochemistry and conducted a survival analysis according to the pathological stage. The 5-year event-free survival (EFS) and disease-specific survival (DSS) hazard ratios (HRs) of the low 8-OHdG subgroup were 1.41 (95% confidence interval (CI): 1.01-1.98, p = 0.04) and 1.60 (95% CI: 1.12-2.28, p = 0.01), respectively. When tumor node metastasis (TNM) staging and 8-OHdG expression were combined, the 5-year EFS and DSS HRs of patients with CRC with low 8-OHdG expression cancer at the same TNM stage (stage Ⅲ/Ⅳ) were 1.51 (95% CI: 1.02-2.22, p = 0.04) and 1.64 (95% CI: 1.09-2.48, p = 0.02), respectively, compared to those with high 8-OHdG expression cancer, indicating a poor prognosis. Therefore, low 8-OHdG expression is a significant predictive factor for 5-year EFS and DSS in patients with CRC, and it can serve as an essential biomarker of CRC.

p53 expression is associated with tumor stage, grade and subtype in patients with hepatocellular carcinoma

The present study aimed to determine the expression levels of p53 in patients with hepatocellular carcinoma (HCC) and to evaluate its association with several HCC-related prognostic factors and in particular, with tumor stage, grade and subtype. Therefore, a cross-sectional study, involving 41 patients with HCC, who underwent surgical resection between January, 2013 and December, 2020 was conducted. To assess the expression levels of p53 in all patients with HCC, immunohistochemical staining was performed. In addition, the association between p53 expression and the clinicopathological characteristics of patients with HCC, including prognostic factors, was evaluated by applying the appropriate statistical analysis methods. The results revealed that among the 41 patients enrolled, 35 patients (85.4%) were positive for p53 expression. A higher percentage of positive p53 expression was observed in male patients >60 years old, with single HCC nodules >5 cm in diameter and vascular invasion, compared with their counterparts. A positive p53 expression was associated with well- and poorly differentiated HCC, but not with tumor stage and subtype. No differences in p53 expression were observed across different tumor stages and subtypes. Additionally, patients with moderately and poorly differentiated HCC exhibited significantly higher p53 expression levels compared with those suffering from well-differentiated HCC. Overall, the results demonstrated that the rate of p53 immuno-positive cells was increased in patients with HCC. In addition, p53 expression was associated with well- and poorly differentiated HCC, thus suggesting its association with a poorer prognosis.

Role of p53 suppression in the pathogenesis of hepatocellular carcinoma

In the world, hepatocellular carcinoma (HCC) is among the top 10 most prevalent malignancies. HCC formation has indeed been linked to numerous etiological factors, including alcohol usage, hepatitis viruses and liver cirrhosis. Among the most prevalent defects in a wide range of tumours, notably HCC, is the silencing of the p53 tumour suppressor gene. The control of the cell cycle and the preservation of gene function are both critically important functions of p53. In order to pinpoint the core mechanisms of HCC and find more efficient treatments, molecular research employing HCC tissues has been the main focus. Stimulated p53 triggers necessary reactions that achieve cell cycle arrest, genetic stability, DNA repair and the elimination of DNA-damaged cells’ responses to biological stressors (like oncogenes or DNA damage). To the contrary hand, the oncogene protein of the murine double minute 2 (MDM2) is a significant biological inhibitor of p53. MDM2 causes p53 protein degradation, which in turn adversely controls p53 function. Despite carrying wt-p53, the majority of HCCs show abnormalities in the p53-expressed apoptotic pathway. High p53 in-vivo expression might have two clinical impacts on HCC: (1) Increased levels of exogenous p53 protein cause tumour cells to undergo apoptosis by preventing cell growth through a number of biological pathways; and (2) Exogenous p53 makes HCC susceptible to various anticancer drugs. This review describes the functions and primary mechanisms of p53 in pathological mechanism, chemoresistance and therapeutic mechanisms of HCC.

Vitamin D ameliorates diethylnitrosamine-induced liver preneoplasia: A pivotal role of CYP3A4/CYP2E1 via DPP-4 enzyme inhibition

Growing evidence has indicated that vitamin D (Vit D) regulates cell proliferation and differentiation in cancer cells. Accordingly, the present study was conducted to investigate the possible beneficial effects of Vit D on diethylnitrosamine (DEN)-induced liver preneoplasia. The effect of Vit D on HepG2 cells was investigated using MTT assay. Additionally, liver preneoplasia was induced in Swiss male albino mice by giving overnight fasted animals 5 consecutive doses of DEN (75 mg/kg/week). Oral treatment with Vit D (200 IU/kg/day) was initiated either 2 weeks before DEN (first protocol) or 1 week after the first dose of DEN injection (second protocol). At the end of the experiment, tissue levels of GGT, DPP-4, TNF-α, IL-6, CYP2E1, and CYP3A4 were also estimated. Moreover, the histopathological study of liver tissue and immunohistochemical detection of GST-P, PCNA, and NF-κB were performed. Vit D exerted a significant cytotoxic effect on HepG2 cells via significantly increasing BAX, p53, and BAX/Bcl2 ratio, and significantly decreasing Bcl2 mRNA expression. In both in vivo protocols, Vit D was capable of normalizing relative liver weight, PCNA, altered hepatocellular foci, and ductular proliferation. Moreover, Vit D significantly reduced the DEN-induced elevation of AST, ALT, ALP, GGT, DDP-4, TNF-α, IL-6, CYP2E1, liver DNA damage, GST-P, NF-κB, nuclear hyperchromasia/pleomorphism, cholestasis, and inflammatory cell aggregates, but significantly increased CYP3A4 content. In conculsion, current results reflect the potential impact of Vit D in the management of early stages of liver cancer.

Apoptotic effect of sulfated galactofucan from marine macroalga Turbinaria ornata on hepatocellular and ductal carcinoma cells

Tumor protein or cellular tumor antigen p53, is considered a critical transcriptional regulation factor, which can suppress the growth of tumor cells by activating other functional genes. The current study appraised the p53 activation pathways, which could be used as an alternative therapeutic strategy for the treatment of hepatocellular and ductal carcinoma. Algal polysaccharides have been used as emerging sources of bioactive natural pharmacophores. A sulfated galactofucan characterized as [→1)-O-4-sulfonato-α-fucopyranose-(3 → 1)-α-fucopyranose-(3→] as the main branch with [→1)-6-O-acetyl-β-galactopyranose-(4→] as side chain isolated from marine macroalga Turbinaria ornata exhibited prospective apoptosis on HepG2 (hepatocellular carcinoma) and MCF7 (ductal carcinoma) cells. Annexin V-fluorescein isothiocyanate-propidium iodide study displayed higher early apoptosis in MCF7 and HepG2 cell lines (56 and 24.2%, respectively) treated with TOP-3 (at IC50 concentration) than those administered with standard camptothecin. Upregulation of the p53 gene expression was perceived in TOP-3 treated HepG2 and MCF7 cells.

Influence of ethanolic extract of Allium sativum on TP53 gene and its anticancer potential in N-Nitrosodiethylamine (NDEA)-induced hepatocellular carcinoma in male albino rats

Objectives

Cancer is a group of genetic disorders in which the behavior of the cell is disturbed by mutation and other abnormalities thereby posing as the leading cause of morbidity and mortality globally. Hepatocellular Carcinoma (HCC) is the most common form of liver cancer, highly aggressive with high mortality and incidence rate; and has limited therapeutic options. Most of the conventional cancer chemotherapeutics are associated with undesirable side effects, toxicity, chemoresistance, and high treatment cost, driving the need for a safer and more effective treatment alternative. Medicinal plants and herbs have shown very promising anti-cancer properties which are important for cancer treatment due to their multiple chemical compounds.

Materials and Methods

Qualitative screening of the ethanolic extractof Allium sativum was conducted showing the different phytochemicalspresent. The levels of liver function and hematological parameters wasdetermined via spectrophotometric analysis. Polymerase Chain Reaction techniquewas used to assess the gene patterns of Tumorsuppressor p53 (TP53).

Results

Phytochemical analysis revealed that Allium sativum has properties that antagonize the proliferating process of carcinogenesis in the liver. The NDEA-group showed significant distortion in the liver architecture characterized by vascular congestion of blood sinusoids, cirrhosis, and congestive hepatopathy while the treated groups showed a reduction in the abnormalities and malignant formation. The treated group showed a significant (P<0.05) increase and restored activities of Alanine aminotransferase (ALT), Aspartate aminotransferase (AST), Alkaline phosphatase (ALP), Bilirubin and hematological parameters (RBCs, WBCs, and Platelets). TP53 gene amplification was significantly (P<0.05) visible after treatment.

Conclusion

Ethanolic plant extract of A. sativum demonstrates its anticancer properties by improving the liver architecture, increasing the antioxidant defense systems, and activation of the tumor suppressor (TP53) gene. Garlic extract has anti-proliferating properties and can be used as an alternative mode of treatment and prevention for hepatocellular carcinoma.

Hepcidin in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common reasons for cancer-related deaths. Excess iron increases HCC risk. Inevitably, hepcidin, the iron hormone that maintains systemic iron homoeostasis is involved in HCC pathology. Distinct from other cancers that show high hepcidin expression, HCC patients can show low hepcidin levels. Thus, it is of immense clinical benefit to address the regulation and action of hepcidin in HCC as this may help in identifying molecular targets for diagnosis, prognosis, and therapeutics. Accordingly, this review explores hepcidin in HCC. It presents the levels of tissue and serum hepcidin and explains the mechanisms that contribute to hepcidin reduction in HCC. These include downregulation of HAMP, TfR2, HJV, ALK2 and circular RNA circ_0004913, upregulation of matriptase-2 and GDF15, inactivation of RUNX3 and mutation in TP53. The enigmas around mir-122 and the functionalities of two major hepcidin inducers BMP6 and IL6 in relation to hepcidin in HCC are discussed. Effects of hepcidin downregulation are explained, specifically, increased cancer proliferation via activation of CDK1/STAT3 pathway and increased HCC risk due to reduction in a hepcidin-mediated protective effect against hepatic stellate cell activation. Hepcidin–ferroportin axis in HCC is addressed. Finally, the role of hepcidin in the diagnosis, prognosis and therapeutics of HCC is highlighted.

Subacute Toxic Effects of Silver Nanoparticles oral Administration and Withdrawal on the Structure and Function of Adult Albino Rats’ Hepatic Tissue

Products containing Silver nanoparticles (Ag NPs) are becoming vastly used in our daily life. The widespread increased introduction of Ag NPs in many aspects of life has raised researchers' concerns regarding their safety and toxicity for biological and environmental life in the past few years. The current study aimed to explore the subsequent effects of Ag NPs withdrawal, following short-term oral administration. Eighteen rats were assigned randomly into three groups (control group "1" and AG NPs treated groups "2" and "3"; 6 animals each). The control group received normal food and tap water while groups 2 & 3 received 0.5 ml of a solution containing 25 ppm Ag NPs for 14 days. Group 2 rats were sacrificed on day 14 whereas group 3 was left for another 14 days of particle cessation followed by euthanasia on day 28. Functional assessment was done by liver enzyme assays, hydrogen peroxide activity, hepatic Bdnf expression, and P53 immunoreactivity. Hepatic tissue structural assessment was done via hematoxylin and eosin, periodic acid-Schiff as well as Masson's trichrome stains. The results revealed a significant elevation of Hydrogen peroxide in group 2 only compared to the control group. Hepatic Bdnf and liver enzymes were both insignificantly affected. Structural abnormalities and enhanced apoptosis in hepatic tissue were found 14 days after ceasing the nanoparticles. In conclusion: Structural and functional insults following Ag NPs oral administration continues after particle withdrawal, and interestingly they do not necessitate apparent reflection on liver enzyme assays.

Inducible Liver Cancer Models in Transgenic Zebrafish to Investigate Cancer Biology

Primary liver cancer is one of the most prevalent and deadly cancers, which incidence continues to increase while treatment response remains poor; thus, in-depth understanding of tumour events is necessary to develop more effective therapies. Animal models for liver cancer are powerful tools to reach this goal. Over the past decade, our laboratory has established multiple oncogene transgenic zebrafish lines that can be robustly induced to develop liver cancer. Histological, transcriptomic and molecular analyses validate the use of these transgenic zebrafish as experimental models for liver cancer. In this review, we provide a comprehensive summary of our findings with these inducible zebrafish liver cancer models in tumour initiation, oncogene addiction, tumour microenvironment, gender disparity, cancer cachexia, drug screening and others. Induced oncogene expression causes a rapid change of the tumour microenvironment such as inflammatory responses, increased vascularisation and rapid hepatic growth. In several models, histologically-proven carcinoma can be induced within one week of chemical inducer administration. Interestingly, the induced liver tumours show the ability to regress when the transgenic oncogene is suppressed by the withdrawal of the chemical inducer. Like human liver cancer, there is a strong bias of liver cancer severity in male zebrafish. After long-term tumour progression, liver cancer-bearing zebrafish also show symptoms of cancer cachexia such as muscle-wasting. In addition, the zebrafish models have been used to screen for anti-metastasis drugs as well as to evaluate environmental toxicants in carcinogenesis. These findings demonstrated that these inducible zebrafish liver cancer models provide rapid and convenient experimental tools for further investigation of fundamental cancer biology, with the potential for the discovery of new therapeutic approaches.

MiR-9-3p regulates the biological functions and drug resistance of gemcitabine-treated breast cancer cells and affects tumor growth through targeting MTDH

This study explored the role of MTDH in regulating the sensitivity of breast cancer cell lines to gemcitabine (Gem) and the potential miRNAs targeting MTDH. The expression of MTDH in cancer tissues and cells was detected by immunohistochemical staining or qRT-PCR. The target genes for MTDH were predicted by bioinformatics and further confirmed by dual-luciferase reporter assay and qRT-PCR. Cancer cells were transfected with siMTDH, MTDH, miR-9-3p inhibitor, or mimics and treated by Gem, then CCK-8, colony formation assay, tube formation assay, flow cytometry, wound healing assay, and Transwell were performed to explore the effects of MTDH, miR-9-3p, and Gem on cancer cell growth, apoptosis, migration, and invasion. Expressions of VEGF, p53, cleaved caspase-3, MMP-2, MMP-9, E-Cadherin, N-Cadherin, and Vimentin were determined by Western blot. MTDH was high-expressed in cancer tissues and cells, and the cells with high-expressed MTDH were less sensitive to Gem, while silencing MTDH expression significantly promoted the effect of Gem on inducing apoptosis, inhibiting cell migration, invasion, and growth, and on regulating protein expressions of cancer cells. Moreover, miR-9-3p had a targeted binding relationship with MTDH, and overexpressed miR-9-3p greatly promoted the toxic effects of Gem on cancer cells and expressions of apoptosis-related proteins, whereas overexpressed MTDH partially reversed such effects of overexpressed miR-9-3p. The study proved that miR-9-3p regulates biological functions, drug resistance, and the growth of Gem-treated breast cancer cells through targeting MTDH.

Ubiquitin pathways regulate the pathogenesis of chronic liver disease

Chronic liver disease (CLD) is considered the leading cause of global mortality. In westernized countries, increased consumption of alcohol and overeating foods with high fat/ high glucose promote progression of CLD such as alcoholic liver disease (ALD) and non-alcoholic liver disease (NAFLD). Accumulating evidence and research suggest that ubiquitin, a 75 amino acid protein, plays crucial role in the pathogenesis of CLD through dynamic post-translational modifications (PTMs) exerting diverse cellular outcomes such as protein degradation through ubiquitin-proteasome system (UPS) and autophagy, and regulation of signal transduction. In this review, we present the function of ubiquitination and latest findings on diverse mechanism of PTMs, UPS and autophagy which significantly contribute to the pathogenesis of alcoholic liver disease (ALD), non-alcoholic fatty liver disease (NAFLD), cirrhosis, and HCC. Despite its high prevalence, morbidity, and mortality, there are only few FDA approved drugs that could be administered to CLD patients. The goal of this review is to present a variety of pathways and therapeutic targets involving ubiquitination in the pathogenesis of CLD. Further, this review summarizes collective views of pharmaceutical inhibition or activation of recent drugs targeting UPS and autophagy system to highlight potential targets and new approaches to treat CLD.

Toward Cancer Diagnostics of the Tumor Suppressor p53 by Surface Enhanced Raman Spectroscopy

The tumor suppressor p53 protein plays a crucial role in many biological processes. The presence of abnormal concentrations of wild-type p53, or some of its mutants, can be indicative of a pathological cancer state. p53 represents therefore a valuable biomarker for tumor screening approaches and development of suitable biosensors for its detection deserves a high interest in early diagnostics. Here, we revisit our experimental approaches, combining Surface Enhanced Raman Spectroscopy (SERS) and nanotechnological materials, for ultrasensitive detection of wild-type and mutated p53, in the perspective to develop biosensors to be used in clinical diagnostics. The Raman marker is provided by a small molecule (4-ATP) acting as a bridge between gold nanoparticles (NPs) and a protein biomolecule. The Azurin copper protein and specific antibodies of p53 were used as a capture element for p53 (wild-type and its mutants). The developed approaches allowed us to reach a detection level of p53 down to 10^-17 M in both buffer and serum. The implementation of the method in a biosensor device, together with some possible developments are discussed.

Triangular Relationship between p53, Autophagy, and Chemotherapy Resistance

Chemotherapy and radiation often induce a number of cellular responses, such as apoptosis, autophagy, and senescence. One of the major regulators of these processes is p53, an essential tumor suppressor that is often mutated or lost in many cancer types and implicated in early tumorigenesis. Gain of function (GOF) p53 mutations have been implicated in increased susceptibility to drug resistance, by compromising wildtype anti-tumor functions of p53 or modulating key p53 processes that confer chemotherapy resistance, such as autophagy. Autophagy, a cellular survival mechanism, is initially induced in response to chemotherapy and radiotherapy, and its cytoprotective nature became the spearhead of a number of clinical trials aimed to sensitize patients to chemotherapy. However, increased pre-clinical studies have exemplified the multifunctional role of autophagy. Additionally, compartmental localization of p53 can modulate induction or inhibition of autophagy and may play a role in autophagic function. The duality in p53 function and its effects on autophagic function are generally not considered in clinical trial design or clinical therapeutics; however, ample pre-clinical studies suggest they play a role in tumor responses to therapy and drug resistance. Further inquiry into the interconnection between autophagy and p53, and its effects on chemotherapeutic responses may provide beneficial insights on multidrug resistance and novel treatment regimens for chemosensitization.

Screening of Natural Stilbene Oligomers from Vitis vinifera for Anticancer Activity on Human Hepatocellular Carcinoma Cells

The characterization of bioactive resveratrol oligomers extracted from Vitis vinifera canes has been recently reported. Here, we screened six of these compounds (ampelopsin A, trans-ε-viniferin, hopeaphenol, isohopeaphenol, R2-viniferin, and R-viniferin) for their cytotoxic activity to human hepatocellular carcinoma (HCC) cell lines p53 wild-type HepG2 and p53-null Hep3B. The cytotoxic efficacy depended on the cell line. R2-viniferin was the most toxic stilbene in HepG2, with inhibitory concentration 50 (IC₅₀) of 9.7 ± 0.4 µM at 72 h, 3-fold lower than for resveratrol, while Hep3B was less sensitive (IC₅₀ of 47.8 ± 2.8 µM). By contrast, hopeaphenol (IC₅₀ of 13.1 ± 4.1 µM) and isohopeaphenol (IC₅₀ of 26.0 ± 3.0 µM) were more toxic to Hep3B. Due to these results, and because it did not exert a large cytotoxicity in HH4 non-transformed hepatocytes, R2-viniferin was selected to investigate its mechanism of action in HepG2. The stilbene tended to arrest cell cycle at G2/M, and it also increased intracellular reactive oxygen species (ROS), caspase 3 activity, and the ratio of Bax/Bcl-2 proteins, indicative of apoptosis. The distinctive toxicity of R2-viniferin on HepG2 encourages research into the underlying mechanism to develop the oligostilbene as a therapeutic agent against HCC with a particular genetic background.

Analysis of TP53 aflatoxin signature mutation in hepatocellular carcinomas from Guatemala: A cross-sectional study (2016-2017)

BACKGROUND AND AIMS

Guatemala has the highest incidence of hepatocellular carcinoma (HCC) in the Western hemisphere. The major risk factors in Guatemala are not well characterized, but the prevalence of hepatitis B virus (HBV) and hepatitis C virus (HCV) appears to be low, while the prevalence of aflatoxin (AFB1) exposure appears to be high. To examine whether AFB1 may contribute to the elevated incidence of HCC in Guatemala, this study examined the frequency of the AFB1-signature mutation in the TP53 gene (R249S) as well as other somatic mutations. In addition, we assessed whether the frequency of the TP53 mutation differed by sex.

METHODS

Formalin-fixed, paraffin-embedded (FFPE) HCC tissues were obtained from three hospitals in Guatemala City between 2016 and 2017. In addition, tumor tissues preserved in RNAlater were also obtained. Sociodemographic and clinical information including HBV and HCV status were collected. Targeted sequencing of TP53 was performed in the FFPE samples, and a panel of 253 cancer-related genes was sequenced in the RNAlater samples.

RESULTS

Ninety-one FFPE tissues were examined, from 52 men and 39 women. Median (IQR) age at diagnosis was 62 (51-70). Among those with known HBV and HCV status, two were HBV+ and three were HCV+. Overall, 47% of the HCCs had a TP53 mutation. The AFB1-signature R249S mutation was present in 24%. No overlap between the R249S mutation and HBV+ was observed in this cohort. Among 18 RNAlater samples examined, 44% had any TP53 mutation and 33% had the R249S mutation. Other somatic mutations were identified in known HCC driver genes.

CONCLUSIONS

The presence of the TP53 R249S mutation in the samples studied suggests that AFB1 may contribute to the high incidence of HCC in Guatemala. The proportion of HBV+ tumors was low, suggesting that AFB1 may be associated with HCC in the absence of concomitant HBV infection. Further investigation of AFB1 and other risk factors for HCC in Guatemala is warranted.

Tumor suppressor ZHX2 inhibits NAFLD-HCC progression via blocking LPL-mediated lipid uptake

Non-alcoholic fatty liver disease (NAFLD) leads to hepatocellular carcinoma (HCC). However, the underlying mechanism remains largely unclear. Here, we investigated the role of the tumor suppressor Zinc fingers and homeoboxes 2 (ZHX2) in the progression of NAFLD to HCC. ZHX2 expression was significantly decreased in fatty liver tissues, especially in the liver with NAFLD–HCC. ZHX2 overexpression disturbed lipid homeostasis of cultured HCC cells, and inhibited lipid deposition in hepatocytes both in vitro and in vivo. Moreover, ZHX2 inhibited uptake of exogenous lipids through transcriptional suppression of lipid lipase (LPL), leading to retarded proliferation of HCC cells. Importantly, LPL overexpression significantly reversed ZHX2-mediated inhibition of HCC cell proliferation, xenograft tumor growth, lipid deposition, and spontaneous liver tumor formation. Consistently, IHC staining demonstrated a negative correlation of ZHX2 with LPL in an HCC cohort. Collectively, ZHX2 protects hepatocytes from abnormal lipid deposition in NAFLD through transcriptional repression of LPL, which subsequently retards cell growth and NAFLD–HCC progression. These findings illustrate a novel mechanism of NAFLD progression into HCC.