Interaction with YAP underlies the species differences between humans and rodents in CAR-dependent hepatocyte proliferation

Constitutive androstane receptor (CAR), a nuclear receptor predominantly expressed in the liver, is activated by diverse chemicals and induces hepatocyte proliferation and hepatocarcinogenesis in rodents. However, the underlying mechanism responsible for CAR-dependent hepatocyte proliferation remains unclear. Importantly, this phenomenon has not been observed in the human liver. This study aimed to investigate the molecular mechanism underlying CAR-induced hepatocyte proliferation and to explore the species differences in hepatocyte proliferation between humans and rodents. Treatment of mice with the CAR activator TCPOBOP induced hepatocyte proliferation and nuclear accumulation of yes-associated protein (YAP), a known liver cancer inducer. This induction was abolished in CAR-knockout mice. Exogenously expressed YAP in cultured cells was accumulated in the nucleus by the coexpression with mouse CAR but not human CAR. Pull-down analysis of recombinant proteins revealed that mouse CAR interacted with YAP, whereas human CAR did not. Further investigations using YAP deletion mutants identified the WW domain of YAP as essential for interacting with CAR and showed that the PY motif (PPAY) in mouse CAR was crucial for binding to the WW domain, whereas human CAR with its mutated motif (PPAH) failed to interact with YAP. A mouse model harboring the Y150H mutation (PPAY to PPAH) in CAR displayed drastically attenuated TCPOBOP-induced hepatocyte proliferation and nuclear accumulation of YAP. CAR induces the nuclear accumulation of YAP through the PY motif-WW domain interaction to promote hepatocyte proliferation. The absence of this interaction in human CAR contributes to the lack of CAR-dependent hepatocyte proliferation in human livers.

Utility of human cytochrome P450 inhibition data in the assessment of drug-induced liver injury

1. Drug-induced liver injury (DILI) is a major cause of drug development discontinuation and drug withdrawal from the market, but there are no golden standard methods for DILI risk evaluation. Since we had found the association between DILI and CYP1A1 or CYP1B1 inhibition, we further evaluated the utility of cytochrome P450 (P450) inhibition assay data for DILI risk evaluation using decision tree analysis.2. The inhibitory activity of drugs with DILI concern (DILI drugs) and no DILI concern (no-DILI drugs) against 10 human P450s was assessed using recombinant enzymes and luminescent substrates. The drugs were also subjected to cytotoxicity assays and high-content analysis using HepG2 cells. Molecular descriptors were calculated by alvaDesc.3. Decision tree analysis was performed with the data obtained as variables with or without P450-inhibitory activity to discriminate between DILI drugs and no-DILI drugs. The accuracy was significantly higher when P450-inhibitory activity was included. After the decision tree discrimination, the drugs were further discriminated with the P450-inhibitory activity. The results demonstrated that many false-positive and false-negative drugs were correctly discriminated by using the P450 inhibition data.4. These results suggest that P450 inhibition assay data are useful for DILI risk evaluation.

Involvement of the CYP1A1 inhibition-mediated activation of aryl hydrocarbon receptor in drug-induced hepatotoxicity

Hepatotoxicity is one of the most common toxicities observed in non-clinical safety studies of drug candidates, and it is important to understand the hepatotoxicity mechanism to assess the risk of drug-induced liver injury in humans. In this study, we investigated the mechanism of hepatotoxicity caused by 2-[2-Methyl-1-(oxan-4-yl)-1H-benzimidazol-5-yl]-1,3-benzoxazole (DSP-0640), a drug candidate that showed hepatotoxicity characterized by centrilobular hypertrophy and vacuolation of hepatocytes in a 4-week oral repeated-dose toxicity study in male rats. In the liver of rats treated with DSP-0640, the expression of aryl hydrocarbon receptor (AHR) target genes, including Cyp1a1, was upregulated. In in vitro reporter assays, however, DSP-0640 showed only minimal AHR-activating potency. Therefore, we investigated the possibility that DSP-0640 indirectly activated AHR by inhibiting the CYP1 enzyme-dependent clearance of endogenous AHR agonists. In in vitro assays, DSP-0640 showed inhibitory effects on both rat and human CYP1A1 and enhanced rat and human AHR-mediated reporter gene expression induced by 6-formylindolo[3,2-b]carbazole, a well-known endogenous AHR agonist. The possible involvement of CYP1A1 inhibition in AHR activation was also demonstrated with other hepatotoxic compounds tacrine and albendazole. These results suggest that CYP1A1 inhibition-mediated AHR activation is involved in the hepatotoxicity caused by DSP-0640 and that DSP-0640 might induce hepatotoxicity in humans as well. We propose that CYP1A1 inhibition-mediated AHR activation is a novel mechanism for drug-induced hepatotoxicity.

Differential DNA-binding and cofactor recruitment are possible determinants of the synthetic steroid YK11-dependent gene expression by androgen receptor in breast cancer MDA-MB 453 cells

Recently, selective androgen receptor modulators (SARMs), which bind to AR and act in a tissue/effect-specific manner, have been developed, but the selective mechanism is not well understood. In this study, we investigated the selective mechanism using the synthetic steroid YK11, which showed AR-mediated gene-selective transactivation. In the AR-positive human breast cancer MDA-MB-453 cells, different patterns of AR-mediated target gene expression and AR recruitment to their enhancer regions were observed between DHT and YK11. A docking study suggested the helices 11 and 12 was moved by the sterically hindered C17-group of YK11. Furthermore, the mutational studies of AR Gln902 and mammalian two-hybrid assays suggested different cofactor recruitment between DHT and YK11. The results of this study suggest that gene selective regulation by SARMs results from differential DNA-binding and/or cofactor recruitment by ligands. These results provide novel insights into the mechanism of action of SARMs.

PXR Suppresses PPARα-Dependent HMGCS2 Gene Transcription by Inhibiting the Interaction between PPARα and PGC1α

Background: PXR is a xenobiotic-responsive nuclear receptor that controls the expression of drug-metabolizing enzymes. Drug-induced activation of PXR sometimes causes drug–drug interactions due to the induced metabolism of co-administered drugs. Our group recently reported a possible drug–drug interaction mechanism via an interaction between the nuclear receptors CAR and PPARα. As CAR and PXR are structurally and functionally related receptors, we investigated possible crosstalk between PXR and PPARα. Methods: Human hepatocyte-like HepaRG cells were treated with various PXR ligands, and mRNA levels were determined by quantitative reverse transcription PCR. Reporter assays using the HMGCS2 promoter containing a PPARα-binding motif and mammalian two-hybrid assays were performed in HepG2 or COS-1 cells. Results: Treatment with PXR activators reduced the mRNA levels of PPARα target genes in HepaRG cells. In reporter assays, PXR suppressed PPARα-dependent gene expression in HepG2 cells. In COS-1 cells, co-expression of PGC1α, a common coactivator of PPARα and PXR, enhanced PPARα-dependent gene transcription, which was clearly suppressed by PXR. Consistently, in mammalian two-hybrid assays, the interaction between PGC1α and PPARα was attenuated by ligand-activated PXR. Conclusion: The present results suggest that ligand-activated PXR suppresses PPARα-dependent gene expression by inhibiting PGC1α recruitment.

Chemical characterization of anemia-inducing aniline-related substances and their application to the construction of a decision tree-based anemia prediction model

Anemia is a well-observed toxicity of chemical substances, and aniline is a typical anemia-inducing substance. However, it remains unclear whether all aniline-like substances with various substituents could induce anemia. We thus investigated the physicochemical characteristics of anemia-inducing substances by decision tree analyses. Training and validation substances were selected from a publicly available database of rat repeated-dose toxicity studies, and discrimination models were constructed by decision tree and bootstrapping methods with molecular descriptors as explanatory variables. To improve the accuracy of discrimination, we individually evaluated the explanatory variables to modify them, established "prerules" that were applied before subjecting a substance to a decision tree by considering metabolism, such as azo reduction and N-dealkylation, and introduced the idea of "partly negative" evaluation for substances having multiple aniline-like substructures. The final model obtained showed 79.2% and 77.5% accuracy for the training and validation dataset, respectively. In addition, we identified some chemical properties that reduce the anemia inducibility of aniline-like substances, including the addition of a sulfonate or carboxy functional group and/or a bulky multiring structure to anilines. In conclusion, the present findings will provide a novel insight into the mechanistic understanding of chemically induced anemia and help to develop a prediction system.

Helix 12 stabilization contributes to basal transcriptional activity of PXR

Pregnane X receptor (PXR) plays an important role in xenobiotic metabolism. While ligand binding induces PXR-dependent gene transcription, PXR shows constitutive transcriptional activity in the absence of ligands when expressed in cultured cells. This constitutive activity sometimes hampers investigation of PXR activation by compounds of interest. In this study, we investigated the molecular mechanism of PXR activation. In the reported crystal structures of unliganded PXR, helix 12 (H12), including a coactivator binding motif, was stabilized, while it is destabilized in the unliganded structures of other nuclear receptors, suggesting a role for H12 stabilization in the basal activity of PXR. Since Phe420, located in the loop between H11 and H12, is thought to interact with Leu411 and Ile414 to stabilize H12, we substituted alanine at Phe420 (PXR-F420A) and separately inserted three alanine residues directly after Phe420 (PXR-3A) and investigated their influence on PXR-mediated transcription. Reporter gene assays demonstrated that the mutants showed drastically reduced basal activity and enhanced responses to various ligands, which was further enhanced by coexpression of the coactivator peroxisome proliferator-activated receptor gamma coactivator 1α. Mutations of both Leu411 and Ile414 to alanine also suppressed basal activity. Mammalian two-hybrid assays showed that PXR-F420A and PXR-3A bound to corepressors and coactivators in the absence and presence of ligands, respectively. We conclude that the intramolecular interactions of Phe420 with Leu411 and Ile414 stabilize H12 to recruit coactivators even in the absence of ligands, contributing to the basal transcriptional activity of PXR. We propose that the generated mutants might be useful for PXR ligand screening.

Identification of average molecular weight (AMW) as a useful chemical descriptor to discriminate liver injury-inducing drugs

Drug-induced liver injury (DILI) is one of major causes of discontinuing drug development and withdrawing drugs from the market. In this study, we investigated chemical properties associated with DILI using in silico methods, to identify a physicochemical property useful for DILI screening at the early stages of drug development. Total of 652 drugs, including 432 DILI-positive drugs (DILI drugs) and 220 DILI-negative drugs (no-DILI drugs) were selected from Liver Toxicity Knowledge Base of US Food and Drug Administration. Decision tree models were constructed using 2,473 descriptors as explanatory variables. In the final model, the descriptor AMW, representing average molecular weight, was found to be at the first node and showed the highest importance value. With AMW alone, 276 DILI drugs (64%) and 156 no-DILI drugs (71%) were correctly classified. Discrimination with AMW was then performed using therapeutic category information. The performance of discrimination depended on the category and significantly high performance (>0.8 balanced accuracy) was obtained in some categories. Taken together, the present results suggest AMW as a novel descriptor useful for detecting drugs with DILI risk. The information presented may be valuable for the safety assessment of drug candidates at the early stage of drug development.

Association of CYP1A1 and CYP1B1 inhibition in in vitro assays with drug-induced liver injury

Drug-induced liver injury (DILI) is one of the major causes for the discontinuation of drug development and withdrawal of drugs from the market. Since it is known that reactive metabolite formation and being substrates or inhibitors of cytochrome P450s (P450s) are associated with DILI, we systematically investigated the association between human P450 inhibition and DILI. The inhibitory activity of 266 DILI-positive drugs (DILI drugs) and 92 DILI-negative drugs (no-DILI drugs), which were selected from Liver Toxicity Knowledge Base (US Food and Drug Administration), against 8 human P450 forms was assessed using recombinant enzymes and luminescent substrates, and the threshold values showing the highest balanced accuracy for DILI discrimination were determined for each P450 enzyme using receiver operating characteristic analyses. The results showed that among the P450s tested, CYP1A1 and CYP1B1 were inhibited by DILI drugs more than no-DILI drugs with a statistical significance. We found that 91% of drugs that showed inhibitory activity greater than the threshold values against CYP1A1 or CYP1B1 were DILI drugs. The results of internal 5-fold cross-validation confirmed the usefulness of CYP1A1 and CYP1B1 inhibition data for the threshold-based discrimination of DILI drugs. Although the contribution of these P450s to drug metabolism in the liver is considered minimal, our present findings suggest that the assessment of CYP1A1 and CYP1B1 inhibition is useful for screening DILI risk of drug candidates at the early stage of drug development.

The influence of the long-term chemical activation of the nuclear receptor pregnane X receptor (PXR) on liver carcinogenesis in mice

Pregnane X receptor (PXR) and constitutive androstane receptor (CAR) are nuclear receptors that are highly expressed in the liver and activated by numerous chemicals. While CAR activation by its activators, such as phenobarbital (PB), induces hepatocyte proliferation and liver carcinogenesis in rodents, it remains unclear whether PXR activation drives liver cancer. To investigate the influence of PXR activation on liver carcinogenesis, we treated mice with the PXR activator pregnenolone 16α-carbonitrile (PCN) with or without PB following tumor initiation with diethylnitrosamine (DEN). After 20 weeks of treatment, preneoplastic lesions detected by immunostaining with an anti-KRT8/18 antibody were observed in PB-treated but not PCN-treated mice, and PCN cotreatment augmented the formation of preneoplastic lesions by PB. After 35 weeks of treatment, macroscopic observations indicated that PB-treated and PB/PCN-cotreated mice had increased numbers of liver tumors compared to control and PCN-treated mice. In the pathological analyses of liver sections, all the mice in the PB and PB/PCN groups developed carcinoma and/or eosinophilic adenoma, but in the PB/PCN group, the multiplicity of carcinoma and eosinophilic adenoma was significantly reduced and the size of carcinoma showed a tendency to decrease. No mouse in the control or PCN-treated group developed such tumors. Differentially expressed gene (DEG) and gene set enrichment analyses in combination with RNA sequencing suggested the increased expression of genes related to epithelial-mesenchymal transition (EMT) in mice cotreated with PCN and PB compared to those treated with PB alone. Changes in the hepatic mRNA levels of epithelial marker genes supported the results of the transcriptome analyses. In conclusion, the present results suggest that PXR activation does not promote hepatocarcinogenesis in contrast to CAR and rather attenuates CAR-mediated liver cancer development by suppressing the EMT of liver cancer cells in rodents.

PXR Functionally Interacts with NF-κB and AP-1 to Downregulate the Inflammation-Induced Expression of Chemokine CXCL2 in Mice

Pregnane X receptor (PXR) is a liver-enriched xenobiotic-responsive transcription factor. Although recent studies suggest that PXR shows anti-inflammatory effects by suppressing nuclear factor kappa B (NF-κB), the detailed mechanism remains unclear. In this study, we aimed to elucidate this mechanism. Mice were treated intraperitoneally with the PXR agonist pregnenolone 16α-carbonitrile (PCN) and/or carbon tetrachloride (CCl₄). Liver injury was evaluated, and hepatic mRNA levels were determined via quantitative reverse transcription polymerase chain reaction. Reporter assays with wild-type and mutated mouse Cxcl2 promoter-containing reporter plasmids were conducted in 293T cells. Results showed that the hepatic expression of inflammation-related genes was upregulated in CCl₄-treated mice, and PCN treatment repressed the induced expression of chemokine-encoding Ccl2 and Cxcl2 among the genes investigated. Consistently, PCN treatment suppressed the increased plasma transaminase activity and neutrophil infiltration in the liver. In reporter assays, tumor necrosis factor-α-induced Cxcl2 expression was suppressed by PXR. Although an NF-κB inhibitor or the mutation of an NF-κB-binding motif partly reduced PXR-dependent suppression, the mutation of both NF-κB and activator protein 1 (AP-1) sites abolished it. Consistently, AP-1-dependent gene transcription was suppressed by PXR with a construct containing AP-1 binding motifs. In conclusion, the present results suggest that PXR exerts anti-inflammatory effects by suppressing both NF-κB- and AP-1-dependent chemokine expression in mouse liver.

Prediction Model of Aryl Hydrocarbon Receptor Activation by a Novel QSAR Approach, DeepSnap-Deep Learning

The aryl hydrocarbon receptor (AhR) is a ligand-dependent transcription factor that senses environmental exogenous and endogenous ligands or xenobiotic chemicals. In particular, exposure of the liver to environmental metabolism-disrupting chemicals contributes to the development and propagation of steatosis and hepatotoxicity. However, the mechanisms for AhR-induced hepatotoxicity and tumor propagation in the liver remain to be revealed, due to the wide variety of AhR ligands. Recently, quantitative structure–activity relationship (QSAR) analysis using deep neural network (DNN) has shown superior performance for the prediction of chemical compounds. Therefore, this study proposes a novel QSAR analysis using deep learning (DL), called the DeepSnap–DL method, to construct prediction models of chemical activation of AhR. Compared with conventional machine learning (ML) techniques, such as the random forest, XGBoost, LightGBM, and CatBoost, the proposed method achieves high-performance prediction of AhR activation. Thus, the DeepSnap–DL method may be considered a useful tool for achieving high-throughput in silico evaluation of AhR-induced hepatotoxicity.

Application of cytochrome P450 reactivity on the characterization of chemical compounds and its association with repeated-dose toxicity

Repeated-dose toxicity (RDT) studies are one of the critical studies to assess chemical safety. There have been some studies attempting to predict RDT endpoints based on chemical substructures, but it remains very difficult to establish such a method, and a more detailed characterization of chemical compounds seems necessary. Cytochrome P450s (P450s) comprise multiple forms with different substrate specificities and play important roles in both the detoxification and metabolic activation of xenobiotics. In this study, we investigated possible use of P450 reactivity of chemical compounds to classify the compounds. A total of 148 compounds with available rat RDT test data were used as test compounds and subjected to inhibition assays against 18 human and rat P450s. Among the tested compounds, 82 compounds inhibited at least one P450 form. Hierarchical clustering analyses using the P450 inhibitory profiles divided the 82 compounds into nine groups, some of which showed characteristic chemical and biological properties. Principal component analyses of the P450 inhibition data in combination with the calculated chemical descriptors demonstrated that P450 inhibition data were plotted differently than most chemical descriptors in the loading plots. Finally, association analyses between P450 inhibition and RDT endpoints showed that some endpoints related to the liver, kidney and hematology were significantly associated with the inhibition of some P450s. Our present results suggest that the P450 reactivity profiles can be used as novel descriptors for characterizing chemical compounds for the investigation of the toxicity mechanism and/or the establishment of a toxicity prediction model.

Role of YAP Activation in Nuclear Receptor CAR-Mediated Proliferation of Mouse Hepatocytes

Constitutive androstane receptor (CAR) is a xenobiotic-responsive nuclear receptor that is highly expressed in the liver. CAR activation induces hepatocyte proliferation and hepatocarcinogenesis in rodents, but the mechanisms remain unclear. In this study, we investigated the association of CAR-dependent cell proliferation with Yes-associated protein (YAP), which is a transcriptional cofactor controlling organ size and cell growth through the interaction with various transcriptional factors including TEA domain family member (TEAD). In mouse livers, 1,4-bis-(2-[3,5-dichloropyridyloxy])benzene (TCPOBOP) (a mouse CAR [mCAR] activator) treatment increased the nuclear YAP accumulation and mRNA levels of YAP target genes as well as cell-cycle related genes along with liver hypertrophy and verteporfin (an inhibitor of YAP/TEAD interaction) cotreatment tended to attenuate them. Furthermore, in cell-based reporter gene assays, CAR activation enhanced the YAP/TEAD-dependent transcription. To investigate the role of YAP/TEAD activation in the CAR-dependent hepatocyte proliferation, we sought to establish an in vitro system completely reproducing CAR-dependent cell proliferation. Since CAR was only slightly expressed in cultured mouse primary hepatocytes compared with mouse livers and no proliferation was observed after treatment with TCPOBOP, we overexpressed CAR using mCAR expressing adenovirus (Ad-mCAR-V5) in mouse primary hepatocytes. Ad-mCAR-V5 infection and TCPOBOP treatment induced hepatocyte proliferation. Similar results were obtained with immortalized normal mouse hepatocytes as well. In the established in vitro system, CAR-dependent proliferation was strongly inhibited by Yap knockdown and completely abolished by verteporfin treatment. Our present results obtained in in vivo and in vitro experiments suggest that YAP/TEAD activation plays key roles in CAR-dependent proliferation of murine hepatocytes.

Long-term cadmium exposure enhances metallothionein-1 induction after subsequent exposure to high concentrations of cadmium in P1798 mouse lymphosarcoma cells

Cadmium, a ubiquitous heavy metal, is a toxic industrial and environmental pollutant. The initial biological response to cadmium exposure is induction of metallothioneins (MTs), a family of cysteine-rich, low-molecular-weight proteins that bind primarily zinc, cadmium, or both. This MT induction protects against cadmium toxicity by quenching cadmium. However, the effects of long-term cadmium exposure on MT1 gene expression are largely unknown. To investigate these effects, we used P1798 mouse lymphosarcoma cells, in which the MT1 gene is suppressed. As previously reported, MT1 expression remained unchanged after cadmium treatment. However, MT1 induction was observed in cells treated with 0.1 µM cadmium for 7 days, then exposed to 10 µM cadmium for 3 hr. In cells treated with 0.1 µM cadmium for 7 days, the transfected MT1 promoter reporter gene transcription and the cadmium incorporation in response to 10 µM cadmium induction were similar to those in untreated P1798 cells. Bisulfite genomic sequencing revealed that 7 day treatment with 0.1 µM cadmium slightly decreased CpG methylation in the 5´ flanking region of the MT1 gene. Our results together show that cadmium treatment results in MT1 induction and epigenetic modification of the MT1 gene.

Construction of the Database of Rat Repeated-dose Toxicity Tests of Pesticides for the Toxicological Characterization of Hepatocyte Hypertrophy

Liver and hepatocyte hypertrophy can be induced by exposure to chemical compounds, but the mechanisms and toxicological characteristics of these phenomena have not yet been investigated extensively. In particular, it remains unclear whether the hepatocyte hypertrophy induced by chemical compounds should be judged as an adaptive response or an adverse effect. Thus, understanding of the toxicological characteristics of hepatocyte hypertrophy is of great importance to the safety evaluation of pesticides and other chemical compounds. To this end, we have constructed a database of potentially toxic pesticides. Using risk assessment reports of pesticides that are publicly available from the Food Safety Commission of Japan, we extracted all observations/findings that were based on 90-day subacute toxicity tests and 2-year chronic toxicity and carcinogenicity tests in rats. Analysis of the database revealed that hepatocyte hypertrophy was observed for 37-47% of the pesticides investigated (varying depending on sex and testing period), and that centrilobular hepatocyte hypertrophy was the most frequent among the various types of hepatocyte hypertrophy in both the 90-day and 2-year studies. The database constructed in this study enables us to investigate the relationships between hepatocyte hypertrophy and other toxicological observations/findings, and thus will be useful for characterizing hepatocyte hypertrophy.

Long-term entecavir therapy results in falls in serum hepatitis B surface antigen levels and seroclearance in nucleos(t)ide-naïve chronic hepatitis B patients

Entecavir (ETV) is reported to result in suppression of hepatitis B virus DNA (HBV DNA) replication with minimal drug resistance. However, information on the long-term effect of such therapy on serum hepatitis B surface antigen (HBsAg) level and elimination of HBsAg is not available. ETV therapy was started in 553 nucleos(t)ide-naïve patients with chronic hepatitis B infection (HBeAg positive: 45%) in our hospital. Serum HBsAg levels were measured serially by the Architect assay. The median baseline HBsAg was 2180 IU/mL (0.12-243 000 IU/mL), and median follow-up period was 3.0 years, with 529, 475, 355, 247 and 163 patients followed-up for 1, 2, 3, 4 and 5 years, respectively. At year 5, the mean log HBsAg decline from baseline was -0.48 log IU/mL, and the cumulative HBsAg clearance rate was 3.5%. Multivariate analysis identified HBV DNA level at baseline (<3.0 log copies IU/mL, odd ratio = 10.2; 95% confidence interval = 1.87-55.5, P = 0.007) and HBsAg level (<500 IU/mL, odd ratio = 29.4; 95% confidence interval = 2.80-333, P = 0.005) as independent predictors of HBsAg seroclearance. These results indicate that although serum HBsAg level declines gradually during ETV therapy, HBsAg seroclearance remains a rare event.

Abstract P3-11-04: The effect of group intervention therapy for young breast cancer patients under 35 years old

Background: Coping with cancer plays an important role in cancer survivorship. Especially in young patients, coping is significant because of anxieties regarding fertility, body image, heredity, symptoms of premature menopause, and psychosocial stress. According to previous studies, the group intervention therapy is effective in improving emotional difficulties for breast cancer patients. However, there is few demonstrating the efficacy of group intervention for young breast cancer patients.

Methods: Since September 2010, we have conducted a clinical trial of a group intervention, facilitated by breast surgeons, psycho-oncologists, and nurses, for young breast cancer patients who were diagnosed under 35, or 36 years old due to enrolling period, and they had no metastasis. at St Luke's International Hospital (SLIH) in Tokyo, Japan. Each group consisted of 7 to 10 breast cancer patients, who received five weekly sessions. We evaluated the changes in coping strategies, emotional levels, and quality of life (QOL) before, after and 6 month after the group intervention, by using three scales: MAC (Mental Attitude to Cancer) for coping, POMS (Profile of Mood States) for emotional states, and FACT-B (Functional Assessment of Cancer Therapy-Breast) for QOL. MAC scale includes five coping strategies such as Fighting Spirit(FS), Hopelessness(H), Anxious Preoccupation(AP), Anxiety(A), and Fatalism(F). This is an interim report of this clinical trial. Paired T-test was used to statistical evaluation.

Results: At this point, 65 young patients finished the group intervention. Complete data were taken from 61 patients for evaluating score changes between before and after the group interventions. POMS and FACT-B score improved statistically (p = 0.004, p = 0.003). Among MAC's five components, Hopelessness and Anxious Preoccupation improved statistically (p&lt;0.01, p&lt;0.001).

Discussion: This study suggests that the group intervention is promising to improve emotion states, QOL, and coping strategies for young breast cancer patients.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-11-04.

Abstract P3-08-03: Establishing Japanese model “working ring” - Informational, emotional and problem-solving group intervention for working breast cancer survivors

Background: Due to advancement of cancer treatment, the number of cancer survivors is increasing and our society also needs to consider cancer survivorship. Especially the prevalence of breast cancer by age is much younger in Japan than in western countries. About half of them were diagnosed in 30-50’s, and they are considered strong working force in society.

Cancer and its treatment largely affect their working status, therefore support system for workers with cancer is urgently required.

Methods: We established support systems by 3 phases. We assessed the effect of breast cancer and informational needs in Japanese young breast cancer survivors for working with cancer (Phase 1). We also estimated economic impact due to such work force loss from cancer (Phase 2). Furthermore, we designed intervention model “Working Ring” by health care providers for cancer survivors to facilitate returning to work or keeping their job, and evaluated its effect (Phase3).

Results: Among 42 young (less than 35 years old) breast cancer survivors who worked at the time of diagnosis, 33% of them had to changed their role at work after diagnosis of breast cancer. Focused interview revealed they needed informational and emotional support system. According to the Japanese Health Ministry of Health, Labor and Welfare database, we estimated total economic loss due to cancer treatment, $1569 million for women and $2959 million for men. Breast cancer is estimated as a number one cause of economic loss among cancer survivors in Japan. Finally, we introduced group intervention for working survivors provided by health care professionals (psycho-oncologist, nurse, and medical social worker) and labor and social security attorney. In this “Working Ring”, patients were given information about working status, practical issues provided by their companies and our society in order to maintain their work. We enrolled total 22 working breast cancer survivors divided in 3 groups; each group was given by 3 sessions of one-hour group intervention. All attendees of the group intervention showed increase in knowledge and problem solving technique concerning working, and QOL improvement by using POMS.

Discussion: We noted that there are many unmet needs for working breast cancer survivors and loss of their job causes enormous impact for social economy. Surprisingly, breast cancer is estimated number one cause of economic loss from cancer diagnosis in Japan. It is urgently required to establish support systems for working cancer survivors. Our group interventional model “Working Ring” was very successful to improve their anxiety and informational needs. We are currently extending this model through entire Japan.

Conclusions: Most of cancer survivors are considered to be potential working force. To establish a support system for them to maintain working ability and environment is necessary for societal reintegration.

(This work is supported by a Grant-in-Aid for Cancer research from the Japanese Health Ministry of Health, Labor and Welfare, H24-Ganrinsho-ippan-011).

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-08-03.

Augmentation of 3-methylcholanthrene-induced bioactivation in the human hepatoma cell line HepG2 by the calcium channel blocker nicardipine

The abilities of the dihydropyridine calcium channel blocker nicardipine (Nic) to induce cytochrome P450 1 family enzymes (CYP1s) and to enhance the 3-methylcholanthrene (MC)-mediated induction of CYP1s and formation of MC-DNA adduct were examined in the human hepatoma cell line HepG2. The results from real time RT-PCR analysis demonstrated that Nic could induce CYP1 mRNAs and enhance the MC-mediated induction of the CYP1 mRNAs. The luciferase-reporter gene assay using the HepG2-A10 cell line, which has been previously established for the screening of aryl hydrocarbon receptor (AhR) activators, also indicated the augmentation of MC-mediated activation of AhR (induction of luciferase) by Nic, although Nic showed limited capacity for the activation of AhR. Furthermore, the results from the Western blot analysis of CYP1s, the enzyme activity assay, and the assay for MC-DNA adduct formation indicated that Nic could enhance the MC-mediated induction of CYP1s, especially CYP1A1. Furthermore, the intracellular accumulation level of [(3)H]MC after treatment of HepG2 cells with [(3)H]MC significantly increased in the presence of Nic. The present findings demonstrate that Nic can enhance the MC-mediated induction of CYP1s, especially CYP1A1, and the formation of MC-DNA adduct in HepG2 cells. Furthermore, the augmentation of the MC-mediated bioactivation by Nic is demonstrated to occur mainly through an increase in intracellular accumulation of MC.

Occult hepatitis B virus infection increases hepatocellular carcinogenesis by eight times in patients with non-B, non-C liver cirrhosis: a cohort study

An impact of serum hepatitis B virus (HBV) DNA on hepatocarcinogenesis has not been investigated in a cohort of patients with non-B, non-C cirrhosis. Eighty-two consecutive Japanese patients with cirrhosis, who showed negative hepatitis B surface antigen and negative anti-hepatitis C virus, were observed for a median of 5.8 years. Hepatitis B virus core (HBc) region and HBx region were assayed with nested polymerase chain reaction. Both of HBc and HBx DNA were positive in 9 patients (11.0%) and both were negative in 73. Carcinogenesis rates in the whole patients were 13.5% at the end of the 5th year and 24.6% at the 10th year. The carcinogenesis rates in the patients with positive DNA group and negative DNA group were 27.0% and 11.8% at the end of the 5th year, and 100% and 17.6% at the 10th year, respectively (P = 0.0078). Multivariate analysis showed that men (P = 0.04), presence of HBc and HBx DNA (hazard ratio: 8.25, P = 0.003), less total alcohol intake (P = 0.010), older age (P = 0.010), and association of diabetes (P = 0.005) were independently associated with hepatocellular carcinogenesis. Existence of serum HBV DNA predicted a high hepatocellular carcinogenesis rate in a cohort of patients with non-B, non-C cirrhosis.

[Problems in donor lung evaluation for transplantation with regard to airway infection]

The shortage of donor organs has been 1 of the major obstacles to solid organ transplantation. Typical lung donor criteria include clear lung field on chest radiograph, adequate oxygenation, acceptable lung compliance, and satisfactory bronchoscopic findings. To extend usage of available donors, liberalization of donor lung selection criteria has been facilitated, however, marginal donor lungs must be used with discretion, because donor lung injury, especially that related to infection, has a potential leading to early post-operative death of the recipient. From March 2000 to December 2006, we evaluated 15 braindead donors and at least 1 of the lungs from 9 donors was judged suitable for transplantation. One of 9 recipients developed severe pneumonia cased by carbapenems-resistant Pseudomonas aeruginosa possibly originating from the donor lungs, eventually leading to death. The chest radiograph and oxygenation of the donor had been satisfactory, however, a moderate amount of mucopurulent secretions was observed by bronchoscopic inspection and the donor had been given a cefozopran for 9 days before the procurement operation. Remaining 8 recipients were free from air-way infection in the early postoperative period. We discuss the status and problems of donor lung evaluation for transplantation with regard to donor lung infection.

Characterization of the NADH-linked acetylacetoin reductase/2,3-butanediol dehydrogenase gene from Bacillus cereus YUF-4

A 1.4-kbp DNA fragment, including the NADH-linked acetylacetoin reductase/2,3-butanediol dehydrogenase (AACRII/BDH) gene from the chromosomal DNA of Bacillus cereus YUF-4, was cloned in Escherichia coli DH5alpha after its insertion into pUC119, and the resulting plasmid was named pAACRII119. The AACRII/BDH gene had an open reading frame consisting of 1047 bp encoding 349 amino acids. The enzyme exhibited not only AACR activity, but also BDH activity. However, the gene was not located in a 2,3-butanediol (BD) operon, as is the case in the BDH gene of Klebsiella pneumoniae and that of K. terrigena. In addition, there was no BD-cycle-related enzyme gene in the region surrounding the AACRII/BDH gene. The AACR and BDH activities in E. coli DH5alpha/pAACRII119 were 200-fold higher than those in the original B. cereus YUF-4. The characteristics of the AACRII/BDH from E. coli DH 5alpha/pAACRII119 are similar to those of the AACRII/BDH from B. cereus YUF-4. The AACRII/BDH was considered to belong to the NAD(P)- and zinc-dependent long-chain alcohol dehydrogenase (group I ADH) family on the basis of the following distinctive characteristics: it possessed 14 strictly conserved residues of microbial group I ADH and consisted of about 350 amino acids. The enzymatic and genetic characteristics of AACRII/BDH were completely different from those of BDHs belonging to the short-chain dehydrogenase/reductase family. These findings indicated that the AACRII/BDH could be considered a new type of BDH.

[Schwannoma arising from brachial plexus with intrathoracic extension; report of a case]

We report a case of schwannoma arising from brachial plexus with intrathoracic extension. An 18-year-old man demonstrated a tumor shadow at the right pulmonary apex area. In the 2-months of follow-up, tumor size had been growing rapidly. Chest computed tomography (CT) and magnetic resonance imaging (MRI) revealed a giant tumor mass infiltrated right lung. We perfomed operation under the posterolateral incision approach. The pathological diagnosis was schwannoma. We resected this tumor safely and conserved with the seventh, eighth cervical nerve of the brachial plexus under posterolateral incision approach.

Single nucleotide polymorphism of the MxA gene promoter influences the response to interferon monotherapy in patients with hepatitis C viral infection

The biological activity of interferon (IFN) is mediated by the induction of intracellular antiviral proteins, such as 2'-5' oligoadenylate synthetase, dsRNA-activated protein kinase and MxA protein. Among these, MxA protein is assumed to be the most specific surrogate parameter for IFN action. This study was performed to elucidate whether a single nucleotide polymorphism (SNP) (G/T at nt-88) in the promoter region of the MxA gene influences the response to IFN therapy in patients with chronic hepatitis C virus (HCV) infection. Polymorphisms of the MxA gene in 235 HCV patients were determined by polymerase chain reaction-restriction fragment length polymorphism. The frequency of SNP was compared between sustained-responders (n = 78) and nonresponders (n = 157), as determined by biochemical and virological responses to IFN. Multivariate analysis showed that among all patients, HCV genotype, HCV RNA level and the SNP of the MxA gene were independent and significant determinants of the outcome of IFN therapy [odds ratio 3.8 (95% confidence interval 2.0-7.0), P < 0.0001; 0.27 (0.15-0.50), P < 0.0001; 1.8 (1.0-3.4), P = 0.0464, respectively]. Furthermore, among patients with a low viral load (< or =2.0 Meq/mL), MxA-T-positive patients were more likely to show a sustained response compared with MxA-T-negative patients [2.87 (1.3-6.3); 62%vs 36%; P = 0.0075]. Our findings suggested that the SNP of the MxA gene is one of the important host factors that independently influences the response to IFN in patients with chronic HCV infection, especially those with a low viral load.

The novel mutation K87E in ribosomal protein S12 enhances protein synthesis activity during the late growth phase in Escherichia coli

Resistance to streptomycin in bacterial cells often results from a mutation in the rpsL gene that encodes the ribosomal protein S12. We found that a particular rpsL mutation (K87E), newly identified in Escherichia coli, causes aberrant protein synthesis activity late in the growth phase. While protein synthesis decreased with age in cells in the wild-type strain, it was sustained at a high level in the mutant, as determined using living cells. This was confirmed using an in vitro protein synthesis system with poly(U) and natural mRNAs (GFP mRNA and CAT mRNA). Other classical rpsL mutations (K42N and K42T) tested did not show such an effect, indicating that this novel characteristic is typical of ribosomes bearing the K87E mutant form of S12, although the K87E mutation conferred the streptomycin resistance and error-restrictive phenotypes also seen with the K42N and K42T mutations. The K87E (but not K42N or K42T) mutant ribosomes exhibited increased stability of the 70S complex in the presence of low concentrations of magnesium. We propose that the aberrant activation of protein synthesis at the late growth phase is caused by the increased stability of the ribosome.

Wild-type precore and core promoter sequences in patients with acute self-limited or chronic hepatitis B

BACKGROUND

Mutations in the precore region and core promoter were compared between patients with acute and chronic hepatitis B.

METHODS

There were 69 patients with acute self-limited hepatitis B and 210 with chronic hepatitis B who had been followed for > 15 years. The hepatitis B virus (HBV) of genotypes A, B and C was detected in 14 (23%), 8 (13%) and 28 (45%) of the patients with acute self-limited hepatitis, respectively, in contrast to 11 (5%), 25 (12%) and 167 (80%) of those with chronic hepatitis.

RESULTS

At presentation, hepatitis B e antigen (HBeAg) in serum was the more common (82% versus 65%, P < 0.05), and the wild-type sequences of the precore region (100% versus 74%, P < 0.001) and core promoter (88% versus 36%, P < 0.00001) were more frequent in the 50 patients with acute self-limited hepatitis than the 203 patients with chronic hepatitis B who were infected with HBV of genotype A, B or C. Wild-types of both the precore region and core promoter persisted in acute self-limited hepatitis, while they decreased from 28% to 10% in chronic hepatitis over the course of > 15 years.

CONCLUSION

HBV with the wild-type sequences of the precore region and core promoter prevails in patients with acute self-limited hepatitis, unlike in patients with chronic hepatitis.

[The establishment of the styles of video-assisted thoracoscopic surgery for spontaneous pneumothorax]

Video-assisted thoracoscopic surgery (VATS) has been widely used in the treatment of a pneumothorax, but the high incidence of recurrence from spontaneous pneumothorax after VATS is an important problem. In this study, we classified the groups into two categories from the thoracoscopic observations, and discussed whether or not there was reappearance of pneumothorax. In addition, we examined whether adjunctive procedure contributes to recurrent of pneumothorax after operation or not. We concluded that there is a tendency to recurrence in the group with multiple and skip lesions in the lung, and then concluded that the cases apical covering with absorbable material sheet and the use of fibrin glue spray was thought to be effective of recurrence of pneumothorax in cases of multiple and skip lesions from the intraoperative findings through the thoracoscopes. Finally, we examined application of Foley catheter for spontaneous pneumothorax under VATS. It is possible that the application of Foley catheter to prevention against recurrence of pneumothorax is a valid method.

[Spontaneous regression of thymoma; report of a case]

A 44-year-old woman was admitted to our hospital with chest pain. Chest roentgenograms and computed tomography (CT) scan revealed an anterior mediastinal tumor and bilateral pleural effusion. However, CT scan 3 days after magnetic resonance imaging (MRI) revealed regression of the tumor. Extended thymo-thymectomy was performed via median sternotomy. The tumor was in the right lobe of the thymus. Pathologically the tumor was diagnosed as a mixed type non-invasive thymoma, but some parts of the tumor cells were necrotic. This is the 10th case of spontaneous regression of thymoma reported in the Japanese literature.

Gonadotropin-releasing hormone increases melatonin release in the pineal gland of the female rat in vitro

To evaluate the effect of gonadotropin-releasing hormone (GnRH) on melatonin ( N-acetyl-5-methoxytryptamine) release and its synthesizing enzyme activities in pineal glands, pineals from adult female rats during diestrus were organ-cultured in a medium containing 10 -12, 10 -10, or 10 -8 M GnRH for 6 h. Melatonin release increased significantly in pineals cultured with 10 -10 and 10 -8 M GnRH compared to controls. However, in pineal glands that were organ-cultured in a medium containing 10 -12 to 10 -8 M GnRH, the activity of arylalkylamine N-acetyltransferase, which is the key regulatory enzyme in melatonin biosynthesis, showed no significant difference from controls. Likewise, GnRH at these concentrations had no significant effect on the activity of pineal hydroxyindole- O-methyltransferase, which catalyzes the final step of melatonin biosynthesis. These results show that GnRH stimulates pineal melatonin release, but suggest that GnRH does not affect its melatonin synthesis.