The serum tenascin C level is a marker of metabolic disorder-related inflammation affecting pancreatic cancer prognosis.

Obesity is a risk factor for pancreatic cancer development, partly due to the tissue environment of metabolic disorder-related inflammation. We aimed to detect a tissue environment marker triggered by obesity-related metabolic disorders related to pancreatic cancer progression. In murine experiments, Bl6/j mice fed a normal diet (ND) or a high-fat diet (HFD) were orthotopically injected with mPKC1, a murine-derived pancreatic cancer cell line. We used stocked sera from 140 pancreatic cancer patients for analysis and 14 colon polyp patients as a disease control. Compared with ND-fed mice, HFD-fed mice exhibited obesity, larger tumors, and worse prognoses. RNA sequencing of tumors identified tenascin C (TNC) as a candidate obesity-related serum tissue environment marker with elevated expression in tumors of HFD-fed mice. Serum TNC levels were greater in HFD-fed mice than in ND-fed mice. In pancreatic cancer patients, serum TNC levels were greater than those in controls. The TNC-high group had more metabolic disorders and greater CA19-9 levels than did the TNC-low group. There was no relationship between serum TNC levels and disease stage. Among 77 metastatic patients treated with chemotherapy, a high serum TNC concentration was an independent poor prognostic factor. Pancreatic cancer patients with high serum TNC levels experienced progression more rapidly.

Interstitial lung disease with prolonged fever that occurred during long-term administration of olaparib in a 74-year-old ovarian cancer patient: Radiological features and considerations for preventing delayed diagnosis.

A 74-year-old woman, who had been receiving olaparib for the treatment of ovarian cancer for more than a year, visited the emergency department complaining of a fever that had lasted for 1 month. She had been taking antipyretics and antibiotics for her fever, but without any effect. Although she had no symptoms other than fever, she had stopped taking olaparib for 1 week before her visit because she had developed anemia caused by myelosuppression from olaparib. After discontinuing olaparib, her maximum body temperature decreased. On admission, chest X-ray revealed no abnormalities, but chest CT showed diffuse ground-glass opacities. Chest CT taken 5 days later showed partial improvement; therefore, we diagnosed her with interstitial lung disease (ILD) associated with olaparib. After short-term steroid treatment, the ground-glass opacities disappeared, and the patient became afebrile. The CT scan taken for tumor evaluation 2 days before the onset of fever showed a few centrilobular nodular opacities and small patchy ground-glass opacities. These findings could indicate early lesions of ILD, but they seemed inconspicuous and nonspecific, and it might have been difficult to diagnose ILD then. To date, few cases of ILD associated with olaparib have been reported. However, based on previous reports, fever is often seen, and CT findings mainly comprise diffuse ground-glass opacities, and in some cases, centrilobular nodular shadows. Thus, in conjunction with the findings of the present case, these characteristics may be representative of olaparib-induced ILD.

Identification of kynurenine and quinolinic acid as promising serum biomarkers for drug-induced interstitial lung diseases.

BACKGROUND: Drug-induced interstitial lung disease (DILD) is a lung injury caused by various types of drugs and is a serious problem in both clinical practice and drug development. Clinical management of the condition would be improved if there were DILD-specific biomarkers available; this study aimed to meet that need. METHODS: Biomarker candidates were identified by non-targeted metabolomics focusing on hydrophilic molecules, and further validated by targeted approaches using the serum of acute DILD patients, DILD recovery patients, DILD-tolerant patients, patients with other related lung diseases, and healthy controls. RESULTS: Serum levels of kynurenine and quinolinic acid (and kynurenine/tryptophan ratio) were elevated significantly and specifically in acute DILD patients. The diagnostic potentials of these biomarkers were superior to those of conventional lung injury biomarkers, Krebs von den Lungen-6 and surfactant protein-D, in discriminating between acute DILD patients and patients with other lung diseases, including idiopathic interstitial pneumonia and lung diseases associated with connective tissue diseases. In addition to identifying and evaluating the biomarkers, our data showed that kynurenine/tryptophan ratios (an indicator of kynurenine pathway activation) were positively correlated with serum C-reactive protein concentrations in patients with DILD, suggesting the potential association between the generation of these biomarkers and inflammation. Our in vitro experiments demonstrated that macrophage differentiation and inflammatory stimulations typified by interferon gamma could activate the kynurenine pathway, resulting in enhanced kynurenine levels in the extracellular space in macrophage-like cell lines or lung endothelial cells. Extracellular quinolinic acid levels were elevated only in macrophage-like cells but not endothelial cells owing to the lower expression levels of metabolic enzymes converting kynurenine to quinolinic acid. These findings provide clues about the molecular mechanisms behind their specific elevation in the serum of acute DILD patients. CONCLUSIONS: The serum concentrations of kynurenine and quinolinic acid as well as kynurenine/tryptophan ratios are promising and specific biomarkers for detecting and monitoring DILD and its recovery, which could facilitate accurate decisions for appropriate clinical management of patients with DILD.

Smoking-Related Interstitial Fibrosis and Smoker's Macrophages.

Smoking-related interstitial lung diseases (SRILDs) are a group of heterogeneous diffuse pulmonary parenchymal diseases associated with tobacco exposure. Smoking-related interstitial fibrosis (SRIF) is relatively recent, a pathologically defined form of SRILDs. SRIF is characterized by the accumulation of macrophages in the alveolar spaces, which is associated with interstitial inflammation and fibrosis. The macrophages frequently contain light brown pigment and are called 'smoker's macrophages'. Patients with SRIF who have clinical evidence of interstitial lung disease are most commonly relatively young, heavy smokers with abnormalities on chest computed tomography showing ground-glass opacities, peripheral consolidation, and reticulation. Although SRIF is caused by cigarette smoking, the exact pathophysiological mechanisms by which smoking causes this type of interstitial fibrosis remain unknown. The degree of fibrosis and appearance of macrophage aggregates are important points of distinction when evaluating and diagnosing SRIF. Macrophage heterogeneity, particularly the activation and function of monocyte-derived alveolar macrophages (Mo-AMs) and interstitial macrophages (IMs), has important implications for the pathogenesis of SRIF and developing treatments. Further researches focused on smoker's macrophages are needed to understand of the pathogenesis of SRIF.

Clinicopathological Characteristics of Everolimus-Associated Interstitial Lung Disease: A Single-Center Consecutive Analysis.

BACKGROUND: Everolimus, a mammalian target of rapamycin inhibitor used as an antineoplastic drug, is associated with a remarkably high incidence of interstitial lung disease (ILD). The clinical and pathological characteristics of ILD caused by everolimus have not been thoroughly investigated; therefore, we aimed to elucidate the features of everolimus-associated ILD. METHODS: We retrospectively reviewed the medical records of patients who received everolimus for cancer treatment at our hospital. Patient backgrounds were compared between the ILD and non-ILD groups. Chest computed tomography (CT), changes in biomarkers, and lung histopathological features were analyzed for ILD cases. RESULTS: Sixty-six patients were reviewed, and ILD developed in 19. There were no differences in patient demographics between the ILD and non-ILD groups. The severity of ILD was grade 1 (G1) in 9 and grade 2 (G2) in 10 cases. Chest CT showed organizing pneumonia (OP) or a hypersensitive pneumonia pattern. The levels of lactate dehydrogenase, C-reactive protein, Krebs von den lungen-6, and surfactant protein-D (SP-D) at the onset of ILD were significantly higher than those at baseline. Analysis of G1 and G2 ILD subgroups showed a higher SP-D levels in the G2 subgroup. Five patients underwent lung biopsies; all specimens demonstrated alveolitis with lymphocytic infiltration and granulomatous lesions, and some had OP findings. CONCLUSIONS: Everolimus-associated ILD is mild and has a favorable prognosis. Patients with symptomatic ILD were more likely to have higher SP-D levels than those with asymptomatic ILD. Granulomatous lesions are an important pathological feature of everolimus-associated ILD.

Clinical and imaging features of interstitial lung disease in cancer patients treated with trastuzumab deruxtecan.

BACKGROUND: Interstitial lung disease/pneumonitis (ILD/pneumonitis) has been identified as a drug-related adverse event of special interest of trastuzumab deruxtecan (T-DXd), but there were a few reports of T-DXd-related ILD/pneumonitis in clinical practice. METHODS: Between May 25, 2020 (the launch of T-DXd in Japan) and February 24, 2022, there were 287 physician-reported potential ILD/pneumonitis cases from the Japanese post-marketing all-case surveillance. By February 27, 2022, an independent adjudication committee assessed 138 cases and adjudicated 130 cases as T-DXd-related ILD/pneumonitis. The clinical features and imaging characteristics of these cases were evaluated. RESULTS: The majority of adjudicated T-DXd-related ILD/pneumonitis cases were grade 1 or 2 (100/130, 76.9%). The most common radiological pattern types observed were organizing pneumonia patterns (63.1%), hypersensitivity pneumonitis patterns (16.9%), and diffuse alveolar damage (DAD) patterns (14.6%). Eleven cases (8.5%) from 130 resulted in death; the majority of these (8/11, 72.7%) had DAD patterns. The overall proportion of recovery (including the outcomes of recovered, recovered with sequelae, and recovering) was 76.9%, and the median time to recovery was 83.5 days (interquartile range: 42.25-143.75 days). Most cases (59/71, 83.1%) that were treated with corticosteroids were considered responsive to treatment. CONCLUSIONS: This is the first report to evaluate T-DXd-related ILD/pneumonitis cases in clinical practice. Our findings are consistent with previous reports and suggest that patients with DAD patterns have poor outcomes. Evaluation of a larger real-world dataset may further identify predictors of clinical outcome.

Pulmonary manifestation of inflammatory bowel disease: Two case reports.

Pulmonary involvement associated with inflammatory bowel disease (IBD) are a rare extraintestinal manifestation (EIM) of inflammatory bowel disease (IBD), we herein presented two cases. Case 1: 53-year-old man with Crohn's disease treated with mesalazine and azathioprine. Pulmonary nodular shadows were incidentally detected on chest imaging, and revealed granulomas through transbronchial lung biopsy. Case 2: 68-year-old man with ulcerative colitis treated with mesalazine. He presented with fever and respiratory symptoms, and chest imaging showed multiple nodular infiltrates. He was diagnosed with organizing pneumonia by lung biopsy. Both cases were diagnosed to have pulmonary involvement associated with inflammatory bowel disease (IBD) according to multidisciplinary examination including positron emission tomography-computed tomography (FDG-PET) and pathological test. Pulmonary manifestations with IBD may not always require discontinuation of drugs or additional use of steroids or immunosuppressants.

Increased CTGF expression in alveolar epithelial cells by cyclic mechanical stretch: Its mechanism and the therapeutic effect of pirfenidone.

The mechanisms of fibrosis onset and development remain to be elucidated. However, it has been reported that mechanical stretch promotes fibrosis in various organs and cells, and may be involved in the pathogenesis of pulmonary fibrosis. We demonstrated that ventilator-induced lung hyperextension stimulation in mice increased the expression of connective tissue growth factor (CTGF), a profibrotic cytokine, in lung tissue. Increased CTGF expression induced by cyclic mechanical stretch (CMS) was also observed in vitro using A549 human alveolar epithelial cells. Pathway analysis revealed that the induction of CTGF expression by CMS involved MEK phosphorylation. Furthermore, early growth response 1 (Egr-1) was identified as a transcription factor associated with CTGF expression. Finally, the antifibrotic drug pirfenidone significantly reduced CTGF expression, MEK phosphorylation, and Egr-1 levels induced by CMS. Thus, our results demonstrated that profibrotic cytokine CTGF induced by CMS may be a therapeutic target of pirfenidone.

Pulmonary sarcoidosis complicated by rheumatoid arthritis in a patient presenting with progressive fibrosing interstitial lung disease and treated with nintedanib: a case report and literature review.

Sarcoidosis is a multisystem disease with an unknown etiology and is characterized by the formation of noncaseating granulomas in the affected organs. We present the case of a 69-year-old male Japanese patient with bilateral hilar lymphadenopathy on chest radiographs for more than 10 years, left without further investigation. The patient reported no clinical symptoms. Chest computed tomography revealed ground-glass opacities and reticular shadows in both lungs, along with bilateral hilar and mediastinal lymphadenopathy. Lymphocytosis was observed in bronchoalveolar lavage fluid. Pathological examination of transbronchial lung biopsy revealed noncaseating, epithelioid granulomas congruous with sarcoidosis, together with other findings. There were no abnormalities on electrocardiogram, echocardiogram, and ophthalmic examination.For progressive dyspnea on exertion, systemic corticosteroid therapy with oral prednisolone (25 mg/day) was initiated in 2017 and gradually tapered. Despite this intervention, the decline in forced vital capacity (FVC) was accelerated. Three years later, the patient noticed swelling in his right wrist. Further investigation revealed elevated anti-cyclic citrullinated peptide antibodies and absence of noncaseating epithelioid granuloma on surgical biopsy, leading to the diagnosis of rheumatoid arthritis (RA). Thereafter, the anti-fibrotic agent nintedanib was initiated, because interstitial lung disease (ILD) was considered to have converted into a progressive fibrosing phenotype (PF-ILD) with overlapping RA-associated lung involvement. With treatment, the progression of decline in FVC was slowed, although home oxygen therapy was introduced.

A Therapeutically Targetable TAZ-TEAD2 Pathway Drives the Growth of Hepatocellular Carcinoma via ANLN and KIF23.

BACKGROUND & AIMS: Despite recent progress, long-term survival remains low for hepatocellular carcinoma (HCC). The most effective HCC therapies target the tumor immune microenvironment (TIME), and there are almost no therapies that directly target tumor cells. Here, we investigated the regulation and function of tumor cell-expressed Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) in HCC. METHODS: HCC was induced in mice by Sleeping Beauty-mediated expression of MET, CTNNB1-S45Y, or TAZ-S89A, or by diethylnitrosamine plus CCl4. Hepatocellular TAZ and YAP were deleted in floxed mice via adeno-associated virus serotype 8-mediated expression of Cre. TAZ target genes were identified from RNA sequencing, confirmed by chromatin immunoprecipitation, and evaluated in a clustered regularly interspaced short palindromic repeats interference (CRISPRi) screen. TEA domain transcription factors (TEADs), anillin (ANLN), Kif23, and programmed cell death protein ligand 1 were knocked down by guide RNAs in dead clustered regularly interspaced short palindromic repeats-associated protein 9 (dCas9) knock-in mice. RESULTS: YAP and TAZ were up-regulated in murine and human HCC, but only deletion of TAZ consistently decreased HCC growth and mortality. Conversely, overexpression of activated TAZ was sufficient to trigger HCC. TAZ expression in HCC was regulated by cholesterol synthesis, as demonstrated by pharmacologic or genetic inhibition of 3-hydroxy-3-methylglutaryl- coenzyme A reductase (HMGCR), farnesyl pyrophosphate synthase, farnesyl-diphosphate farnesyltransferase 1 (FDFT1), or sterol regulatory element-binding protein 2 (SREBP2). TAZ- and MET/CTNNB1-S45Y-driven HCC required the expression of TEAD2 and, to a lesser extent, TEAD4. Accordingly, TEAD2 displayed the most profound effect on survival in patients with HCC. TAZ and TEAD2 promoted HCC via increased tumor cell proliferation, mediated by TAZ target genes ANLN and kinesin family member 23 (KIF23). Therapeutic targeting of HCC, using pan-TEAD inhibitors or the combination of a statin with sorafenib or anti-programmed cell death protein 1, decreased tumor growth. CONCLUSIONS: Our results suggest the cholesterol-TAZ-TEAD2-ANLN/KIF23 pathway as a mediator of HCC proliferation and tumor cell-intrinsic therapeutic target that could be synergistically combined with TIME-targeted therapies.

A novel germline SMAD4 variant detected in a Japanese family with juvenile polyposis syndrome and hereditary hemorrhagic telangiectasia.

Juvenile polyposis syndrome (JPS) is an autosomal dominant, inherited disorder caused by pathogenic germline variants of mainly SMAD4 or BMPR1A genes. Some patients with JPS, especially with SMAD4 variants, also develop hereditary, hemorrhagic telangiectasia (HHT). HHT is also an autosomal dominant inherited disorder. Herein, we identified a novel germline pathogenic variant of the SMAD4 in a Japanese family with JPS and HHT. A six-base pair deletion in the SMAD4 gene (NM_005359.6:c.1495_1500delTGCATA) was identified in the patients. Two amino acids are deleted from SMAD4 protein (p.Cys499_Ile500del), which are located in MSH2 domain essential for the binding with SMAD3. This is a novel variant that has not been registered in any database surveyed. Amino acid structural analysis predicted significant changes in the secondary and three-dimensional structures in the vicinity of the two amino acids' deletion. The variant is classified as 'Likely Pathogenic' according to the American College of Medical Genetics and Genomics guidelines.

Stratifin as a novel diagnostic biomarker in serum for diffuse alveolar damage.

Among the various histopathological patterns of drug-induced interstitial lung disease (DILD), diffuse alveolar damage (DAD) is associated with poor prognosis. However, there is no reliable biomarker for its accurate diagnosis. Here, we show stratifin/14-3-3σ (SFN) as a biomarker candidate found in a proteomic analysis. The study includes two independent cohorts (including totally 26 patients with DAD) and controls (total 432 samples). SFN is specifically elevated in DILD patients with DAD, and is superior to the known biomarkers, KL-6 and SP-D, in discrimination of DILD patients with DAD from patients with other DILD patterns or other lung diseases. SFN is also increased in serum from patients with idiopathic DAD, and in lung tissues and bronchoalveolar lavage fluid of patients with DAD. In vitro analysis using cultured lung epithelial cells suggests that extracellular release of SFN occurs via p53-dependent apoptosis. We conclude that serum SFN is a promising biomarker for DAD diagnosis.

Opposing roles of hepatic stellate cell subpopulations in hepatocarcinogenesis.

Hepatocellular carcinoma (HCC), the fourth leading cause of cancer mortality worldwide, develops almost exclusively in patients with chronic liver disease and advanced fibrosis1,2. Here we interrogated functions of hepatic stellate cells (HSCs), the main source of liver fibroblasts3, during hepatocarcinogenesis. Genetic depletion, activation or inhibition of HSCs in mouse models of HCC revealed their overall tumour-promoting role. HSCs were enriched in the preneoplastic environment, where they closely interacted with hepatocytes and modulated hepatocarcinogenesis by regulating hepatocyte proliferation and death. Analyses of mouse and human HSC subpopulations by single-cell RNA sequencing together with genetic ablation of subpopulation-enriched mediators revealed dual functions of HSCs in hepatocarcinogenesis. Hepatocyte growth factor, enriched in quiescent and cytokine-producing HSCs, protected against hepatocyte death and HCC development. By contrast, type I collagen, enriched in activated myofibroblastic HSCs, promoted proliferation and tumour development through increased stiffness and TAZ activation in pretumoural hepatocytes and through activation of discoidin domain receptor 1 in established tumours. An increased HSC imbalance between cytokine-producing HSCs and myofibroblastic HSCs during liver disease progression was associated with increased HCC risk in patients. In summary, the dynamic shift in HSC subpopulations and their mediators during chronic liver disease is associated with a switch from HCC protection to HCC promotion.

COVID-19-related stigma and its relationship with mental wellbeing: A cross-sectional analysis of a cohort study in Japan.

Objective: Social stigma related to coronavirus disease (COVID-19), i. e., COVID-19 stigma, forms a burden on people socially, economically, and mentally. This study assessed COVID-19 stigma using a scale to identify a population likely to exhibit higher prejudice against COVID-19 itself as well as those infected with COVID-19. Methods: We adapted and modified the Cancer Stigma Scale to assess COVID-19 stigma and used it as the baseline survey of a cohort study in Japan. The questionnaire was disseminated to 1,573 participants (51.7% men) between December 2020 and March 2021. The questionnaire items included the infection status of individuals close to the respondent and their preventive behaviors related to COVID-19, quality of life (QOL; using the EuroQoL 5-Dimension 5-Level [EQ-5D-5L]), and psychological distress (using the 6-item Kessler Psychological Distress Scale [K6]). Exploratory and confirmatory factor analyses were performed to validate the COVID-19 stigma scale, and we further used the structural equation modeling (SEM) to assess the relationship with QOL and psychological distress. Results: COVID-19 stigma was calculated for the 257 (16.3%) participants who responded to the questionnaire. The mean age (standard deviation) was 54.5 (14.4) years, and 50.2% were men. Factor analysis revealed a five-factor model: Awkwardness (feeling uncomfortable being with a person infected before), Severity (fear of not being able to return to normal after infection), Avoidance (attitude of avoiding infected persons), Policy Opposition (expecting more public funding investment), and Personal Responsibility (believing that infected persons themselves are responsible for their infection). Participants > 70 years had the highest scores among other age groups considering all factors except for Policy Opposition. Standardized coefficients in SEM for COVID-19 stigma (latent variable) was highest for Severity (beta = 0.86). Regression coefficients of COVID-19 stigma on K6 and QOL were 0.21 (95% confidence interval [CI] 0.074-0.342) and -0.159 (95% CI -0.295-0.022), respectively. Conclusion: People aged ≥ 70 years are more likely to exhibit COVID-19 stigma. Additionally, the results indicate that COVID-19 stigma impacts QOL and psychological distress.

Kikuchi-Fujimoto disease can present as delayed lymphadenopathy after COVID-19 vaccination.

Following COVID-19 vaccination, ipsilateral axillary and cervical lymphadenopathy may occur, called vaccine-related hypermetabolic lymphadenopathy, which is considered reactive lymphadenopathy. We report here a case of Kikuchi-Fujimoto disease, which occurred three months after vaccination with COVID-19 vaccine. The patient had cervical and axillary lymph node enlargement and a short-term fever that resolved spontaneously after the first and second vaccines. On the 90th day after the first vaccination, the patient developed a high fever and pathologically diagnosed necrotizing lymphadenitis in the axilla, which was diagnosed as Kikuchi-Fujimoto disease. Gallium scintigraphy showed localized swelling and strong uptake in the ipsilateral axilla. It implies the possibility of Kikuchi-Fujimoto Disease in axillary drainage lymph nodes in association with COVID-19 vaccine. Although only a few cases have been reported so far, this case is novel because of its later onset and diagnosis based on pathological and gallium scintigraphy imaging findings.

Risk Factors for Therapeutic Intervention of Remdesivir in Mild to Moderate COVID-19-A Single-Center Retrospective Study of the COVID-19 Fourth Pandemic Period in Wakayama, Japan.

Background and Objectives: The incidence of coronavirus disease 2019 (COVID-19) has increased in Wakayama, Japan, due to the spread of the highly infectious B.1.1.7 variant. Before this event, the medical systems were almost unaffected. We aimed to assess the clinical characteristics of patients hospitalized with COVID-19 and the risk factors for therapeutic intervention of remdesivir during the fourth pandemic period in Wakayama, Japan. Materials and Methods: This single-center retrospective study enrolled 185 patients with mild to moderate COVID-19 hospitalized in our hospital without intensive care between 14 March and 31 May 2021. Results: In this period, 125 (67.6%) of the 185 patients had the B.1.1.7 variant. Sixty-three patients (34.1%) required remdesivir treatment. Age upon admission and length of hospitalization were significantly different between remdesivir treatment and careful observation groups (mean (standard deviation); 59.6 (14.7) versus 45.3 (20.6) years; p < 0.001 and median (interquartile range); 10 (9-12) versus 9 (8-10) years; p < 0.001). One patient was transferred to another hospital because of disease progression. At hospital admission, age ≥60 years (odds ratio (OR) 6.90, p < 0.001), a previous history of diabetes mellitus (OR 20.9, p = 0.002), B.1.1.7 variant (OR 5.30; p = 0.005), lower respiratory symptoms (OR 3.13, p = 0.011), headache (OR 3.82, p = 0.011), and fever ≥37.5 °C (OR 4.55, p = 0.001) were independent risk factors to require remdesivir treatment during the admission. Conclusions: Many patients with mild to moderate COVID-19 required the therapeutic intervention of remdesivir during the fourth pandemic period in Wakayama, Japan. From the clinical data obtained at admission, these risk factors could contribute to a prediction regarding the requirement of remdesivir treatment in cases of mild to moderate COVID-19.

Activation of p53 After Irradiation Impairs the Regenerative Capacity of the Mouse Liver.

Radiation therapy is one of the treatment methods for hepatocellular carcinoma. However, radiation tolerance of the liver is low, and the detailed effect of radiation on liver regeneration has not been clarified. C57BL/6J mice or hepatocyte-specific p53 knockout (KO) mice (albumin [Alb]-Cre Trp53flox/flox ) were irradiated with a single fraction of 10 Gy localized to the upper abdomen. We performed 70% partial hepatectomy (PHx) 24 hours after irradiation. Liver regeneration was assessed by proliferation cell nuclear antigen (PCNA)- and Ki-67-positive hepatocyte ratios and liver-to-body weight ratio after PHx. To establish a fibrosis model, CCl4 was orally administered for 8 weeks. The murine hepatocyte cell line BNL CL.2 (CL2) was irradiated with 10 Gy. Irradiation activated p53, induced downstream p21 in the liver, and delayed liver regeneration after PHx. While PHx increased hepatocyte growth factor (HGF) levels and activated Met with or without irradiation in the regenerative liver, it activated Akt and extracellular kinase 1 and 2 (Erk 1/2) less in irradiated mice than in nonirradiated mice. In CL2 cells cultured with HGF, irradiation suppressed cell growth by decreasing phosphorylated Akt and Erk 1/2 levels, which was abolished by small interfering RNA-mediated p53 knockdown but not by p21 knockdown. Hepatocyte-specific knockout of p53 in mice abolished the irradiation-induced suppression of both liver regeneration and Akt and Erk 1/2 activation after PHx. In the fibrotic mouse model, the survival rate after PHx of irradiated p53 KO mice was higher than that of wild-type mice. Conclusion: p53 but not p21 is involved in the impaired regenerative ability of the irradiated liver.

TAZ-induced Cybb contributes to liver tumor formation in non-alcoholic steatohepatitis.

BACKGROUND & AIMS: Non-alcoholic steatohepatitis (NASH) is a leading cause of hepatocellular carcinoma (HCC), but mechanisms linking NASH to eventual tumor formation remain poorly understood. Herein, we investigate the role of TAZ/WWTR1, which is induced in hepatocytes in NASH, in the progression of NASH to HCC. METHODS: The roles of hepatocyte TAZ and its downstream targets were investigated in diet-induced and genetic models of NASH-HCC using gene-targeting, adeno-associated virus 8 (AAV8)-H1-mediated gene silencing, or AAV8-TBG-mediated gene expression. The biochemical signature of the newly elucidated pathway was probed in liver specimens from humans with NASH-HCC. RESULTS: When hepatocyte-TAZ was silenced in mice with pre-tumor NASH using AAV8-H1-shTaz (short-hairpin Taz), subsequent HCC tumor development was suppressed. In this setting, the tumor-suppressing effect of shTaz was not dependent of TAZ silencing in the tumors themselves and could be dissociated from the NASH-suppressing effects of shTaz. The mechanism linking pre-tumor hepatocyte-TAZ to eventual tumor formation involved TAZ-mediated induction of the NOX2-encoding gene Cybb, which led to NADPH-mediated oxidative DNA damage. As evidence, DNA damage and tumor formation could be suppressed by treatment of pre-tumor NASH mice with AAV8-H1-shCybb; AAV8-TBG-OGG1, encoding the oxidative DNA-repair enzyme 8-oxoguanine glycosylase; or AAV8-TBG-NHEJ1, encoding the dsDNA repair enzyme non-homologous end-joining factor 1. In surrounding non-tumor tissue from human NASH-HCC livers, there were strong correlations between TAZ, NOX2, and oxidative DNA damage. CONCLUSIONS: TAZ in pre-tumor NASH-hepatocytes, via induction of Cybb and NOX2-mediated DNA damage, contributes to subsequent HCC tumor development. These findings illustrate how NASH provides a unique window into the early molecular events that can lead to tumor formation and suggest that NASH therapies targeting TAZ might also prevent NASH-HCC. LAY SUMMARY: Non-alcoholic steatohepatitis (NASH) is emerging as the leading cause of a type of liver cancer called hepatocellular carcinoma (HCC), but molecular events in pre-tumor NASH hepatocytes leading to HCC remain largely unknown. Our study shows that a protein called TAZ in pre-tumor NASH-hepatocytes promotes damage to the DNA of hepatocytes and thereby contributes to eventual HCC. This study reveals a very early event in HCC that is induced in pre-tumor NASH, and the findings suggest that NASH therapies targeting TAZ might also prevent NASH-HCC.