Oral anticoagulation therapy in atrial fibrillation patients with advanced chronic kidney disease: CODE-AF Registry

Background and objectives

Advanced chronic kidney disease (CKD), including end-stage renal disease (ESRD) on dialysis, increases thromboembolic risk among patients with atrial fibrillation (AF). This study examined the comparative safety and efficacy of direct-acting oral anticoagulant (DOAC) compared to warfarin or no OAC among AF patients with advanced CKD or ESRD on dialysis.

Methods

Using data from the COmparison study of Drugs for symptom control and complication prEvention of AF (CODE-AF) registry, 260 non-valvular AF patients with advanced CKD (defined as estimated glomerular filtration rate [eGFR] <3 0ml/min per 1.73 m2) or ESRD on dialysis were enrolled from June 2016 to July 2020. The study population was categorized into DOAC, warfarin, and no OAC group, and differences in major or clinically relevant non-major (CRNM) bleeding, stroke/systemic embolism (SE), myocardial infarction/critical limb ischemia (CLI), and death were assessed.

Results

During a median 24 months of follow-up, major or CRNM bleeding risk was significantly reduced in the DOAC group compared to the warfarin group (hazard ratio [HR] 0.21, 95% confidence interval [CI] 0.05 to 0.95, p=0.042). In addition, the risk of composite adverse clinical outcome (major or CRNM bleeding, stroke/SE, myocardial infarction/CLI, and death) was significantly reduced in the DOAC group compared to the no OAC group (HR 0.32, 95% CI 0.11 to 0.96, p=0.043).

Conclusion

Among AF patients with advanced CKD or ESRD on dialysis, DOAC was associated with a lower risk of major or CRNM bleeding compared to warfarin and a lower risk of composite adverse clinical outcome compared to no OAC.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Korean Healthcare Technology R&D project funded by the Ministry of Health & Welfare (HI15C1200, HC19C0130)

Resting heart rate and cardiovascular outcomes in patients with atrial fibrillation: CODE-AF registry

Funding Acknowledgements

Type of funding sources: None.

Background

The prognostic significance of resting heart rate and its therapeutic target in atrial fibrillation (AF) is uncertain.

Purpose

The aim of this study was to investigate the relationships between resting heart rate and cardiovascular outcomes in patients with AF.

Methods

A total of 8,886 patients with AF was included from the COmparison study of Drugs for symptom control and complication prEvention of AF (CODE-AF) registry. Patients were categorized according to baseline heart rate, and cardiovascular outcomes were accessed during a median follow-up of 30 months. The primary outcome was a composite of cardiovascular death, hospitalization due to heart failure, and myocardial infarction/critical limb ischemia.

Results

Compared to heart rate ≥100 beats per minute (bpm), heart rate 80-99 bpm was associated with the lowest risk of primary outcome (adjusted hazard ratio [HR] 0.56, 95% confidence interval [CI] 0.40-0.79, p=0.001). In subgroup of patients with heart failure with preserved ejection fraction (HFpEF), heart rate between 80-99 bpm was associated with reduced risk of primary outcome compared to heart rate ≥100 bpm (HR 0.40, 95% CI 0.16-0.98, p=0.045). However, in patients with heart failure with reduced ejection fraction (HFrEF), there was no association between resting heart rate and cardiovascular outcomes (P for interaction 0.001).

Conclusion

Resting heart rate was associated with cardiovascular outcomes in patients with AF, and those with a resting heart rate between 80-99 bpm had the lowest risk of adverse events. The impact of resting heart rate on adverse events persisted in patients with concomitant HFpEF but was not apparent in those with concomitant HFrEF.

P643 A case of Fabry cardiomyopathy refractory to enzyme replacement therapy; the importance of early diagnosis and treatment in Fabry cardiomyopathy

A 56-year-old male was referred in order to identify Fabry disease after his older brother was confirmed as Fabry disease of cardiac variant type. He had been treated with hypertrophic cardiomyopathy (HCMP) five years ago. He didn’t have a history of hypertension. Blood pressure was 118/65 mmHg and pulse rate was 75 beats per minute. Serum creatinine was 1.07 mg/dl and estimated glomerular filtration rate was 75.2 ml/min. Cardiac enzymes including CK-MB and troponin-T were normal. There was no proteinuria on urinalysis. A 12-leads electrocardiogram revealed normal sinus rhythm with severe left ventricular hypertrophy (LVH) and strain pattern. Transthoracic echocardiogram (TTE) showed diffuse severe concentric hypertrophy of the left ventricle (LV) of an average ventricular wall thickness of 17 mm with normal systolic function (left ventricular ejection fraction (LVEF), 56%). TTE also revealed left ventricular outflow tract obstruction with systolic anterior motion of mitral valve. Right ventricle (RV) was also hypertrophied (RV free wall thickness, 7mm). Also, echocardiography revealed findings of diastolic dysfunction; left atrial enlargement, mitral inflow of a pseudo-normal pattern on pulsed wave Doppler image and an increased left ventricular filling pressure on tissue Doppler image (E/e’=20). Cardiac magnetic resonance imaging (MRI) revealed diffuse LV and RV hypertrophy and preserved LV systolic function with hypokinesia of mid-septal LV wall. Delayed hyper-enhancement (DHE) was not found within entire myocardium. A coronary CT angiography was performed because of regional wall motion abnormality but did not show any significant stenoses. He was confirmed as Fabry disease with the same genetic mutation as his brother. He did not present symptoms and signs of any other organs besides only myocardial hypertrophy. He received enzyme replacement therapy (ERT) with intravenous agalsidase-beta every other week via outpatient department for 3 years. Recently, TTE was performed and showed diffuse severe concentric LVH of an average ventricular wall thickness increased to 19 mm despite regularly ERT. Focal intramural and subepicardial DHE was newly developed at LV basal lateral and septal wall on cardiac MRI. Neutralizing antibody against agalsidase -beta was not found in serum.

Fabry disease of cardiac variant type can be delayed in diagnostic aspect because of absence of typical symptoms and signs. Despite the absence of neutralizing antibody, ERT did not prevent both further myocardial hypertrophy and myocardial fibrosis in patient with advanced myocardial hypertrophy caused by delayed diagnosis of Fabry disease. Suspicion of Fabry disease through detailed history taking including family history in patients with diffuse ventricular hypertrophy on an echocardiography can lead to early diagnosis and treatment and can result in improvement in a clinical outcome.

Diagnostic Reference Levels for Adult Nuclear Medicine Imaging Established from the National Survey in Korea

Purpose

There is substantial need for optimizing radiation protection in nuclear medicine imaging studies. However, the diagnostic reference levels (DRLs) have not yet been established for nuclear medicine imaging studies in Korea.

Materials and Methods

The data of administered activity in 32 nuclear medicine imaging studies were collected from the Korean Society of Nuclear Medicine (KSNM) dose survey database from 2013 and 2014. Through the expert discussions and statistical analyses, the 75th quartile value (Q3) was suggested as the preliminary DRL values. Preliminary DRLs were subjected to approval process by the KSNM Board of Directors and KSNM Council, followed by clinical applications and performance rating by domestic institutes.

Results

DRLs were determined through 32 nuclear medicine imaging studies. The Q3 value was considered as appropriate selection as it was generally consistent with the most commonly administered activity. In the present study, the final version of initial DRL values for nuclear medicine imaging in Korean adults is described including various protocols of the brain and myocardial perfusion imaging.

Conclusion

The first DRLs for nuclear medicine imaging in Korean adults were confirmed. The DRLs will enable optimized radiation protection in the field of nuclear medicine imaging in Korea.

Abstract 4931: Validation of Trastuzumab immunohistochemistry as a predictive and prognostic biomarker in gastric cancer patients

Although HER2 immunohistochemistry (IHC) is widely used to assess the HER2 status, not all patients could be clarified with HER2 IHC positivity for Trastuzumab treatment. Here, we introduce a novel IHC method utilizing Trastuzumab itself; compared to conventional HER2 IHC, the new method evaluates the extracellular epitope which is the target of action for Trastuzumab. The purpose of this study is to test whether this new method has better performance in predicting treatment outcome of Trastuzumab therapy, and whether it is the significant prognostic factor in consecutive gastric cancer patients.

From two individual institutions, 37 and 32 GC patients treated with Trastuzumab were enrolled respectively, the former as the training cohort and the latter for validation, and progression free survivals (PFS) were compared according to the results of Trastuzumab IHC. To validate the prognostic significance of Trastuzumab IHC in consecutive GC, we constructed tissue microarrays (TMA) from 536 consecutive cases and Trastuzumab IHC, HER2 IHC, and HER2 silver in situ hybridization (SISH) were performed.

In training cohort (n = 37), all cases were HER2 IHC 2+ (n = 11) or 3+ (n = 26), but 2+ in 3 cases (8.1%) and 3+ in 10 cases (27.0%) by Trastuzumab IHC. Similar results were observed in validation cohort, 17 of 32 cases (53.1%) were 2+ or 3+ by Trastuzumab IHC. Trastuzumab ≥2+ group in the training cohort had significantly better PFS than Trastuzumab <2+ group (p = 0.016), and survival analysis of PFS in validation cohort and combined cohort also showed favorable PFS in Trastuzumab ≥2+ group (p = 0.031 and 0.001, respectively). By Cox regression analysis in training cohort, Trastuzumab IHC ≥2+ was proved to be the independent predictive factor for PFS in patients receiving Trastuzumab. Of 536 consecutive cases of GC, 23 (4.3%) were HER2 IHC 3+, and among these patients, only 5 (21.7%) were also 3+ by Trastuzumab IHC. Disease specific survival (DSS) and overall survival (OS) in Trastuzumab IHC ≥2+ group were shorter compared to Trastuzumab IHC <2 group (p = 0.015 and 0.063, respectively), while both HER2 IHC and HER2 SISH failed to discriminate significant survival differences between subgroups.

In this study, we demonstrated that Trastuzumab IHC is a significant predictive factor for PFS in Trastuzumab-treated GC patients, and poor prognostic factor of DSS in consecutive GC, even better than conventional HER2 IHC and HER2 SISH. We believe that Trastuzumab IHC is a very promising, relatively easy-to-implement, novel method to assess HER2 status in routine clinical practice.

Citation Format: Jiwon Koh, Soo Kyung Nam, Younwoo Lee, Chan-Young Ock, Jin Won Kim, Keun-Wook Lee, Do-Youn Oh, Do Joong Park, Hyung-Ho Kim, Keon-Wook Kang, Woo Ho Kim, Ho-Young Lee, Hye Seung Lee. Validation of Trastuzumab immunohistochemistry as a predictive and prognostic biomarker in gastric cancer patients. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4931.

Association between information provision and decisional conflict in cancer patients

BACKGROUND

In this study, we aimed to identify demographic and clinical variables that correlate with perceived information provision among cancer patients and determine the association of information provision with decisional conflict (DC).

PATIENTS AND METHODS

We enrolled a total of 625 patients with cancer from two Korean hospitals in 2012. We used the European Organization for Research and Treatment of Cancer (EORTC) quality-of-life questionnaire (QLQ-INFO26) to assess patients' perception of the information received from their doctors and the Decisional Conflict Scale (DCS) to assess DC. To identify predictive sociodemographic and clinical variables for adequate information provision, backward selective logistic regression analyses were conducted. In addition, adjusted multivariate logistic regression analyses were carried out to identify clinically meaningful differences of perceived level of information subscales associated with high DC.

RESULTS

More than half of patients with cancer showed insufficient satisfaction with medical information about disease (56%), treatment (73%), other services (83%), and global score (80%). In multiple logistic regression analyses, lower income and education, female, unmarried status, type of cancer with good prognosis, and early stage of treatment process were associated with patients' perception of inadequate information provision. In addition, Information about the medical tests with high DCS values clarity [adjusted odds ratio (aOR), 0.54; 95% confidence interval (CI) 0.30-0.97] and support (aOR, 0.53; 95% CI 0.33-0.85) showed negative significance. For inadequate information perception about treatments and other services, all 5 DCS scales (uncertainty, informed, values clarity, support, and effective decision) were negatively related. Global score of inadequate information provision also showed negative association with high DCS effective decision (aOR, 0.43; 95% CI 0.26-0.71) and DCS uncertainty (aOR, 0.46; 95% CI 0.27-0.77).

CONCLUSION

This study found that inadequate levels of perceived information correlated with several demographic and clinical characteristics. In addition, sufficient perceived information levels may be related to low levels of DC.

Discovery of novel 2,5-dioxoimidazolidine-based P2X(7) receptor antagonists as constrained analogues of KN62

Novel 2,5-dioxoimidazolidine-based conformationally constrained analogues of KN62 (1) were developed as P2X7 receptor (P2X7R) antagonists using a rigidification strategy of the tyrosine backbone of 1. SAR analysis of the 2,5-dioxoimidazolidine scaffold indicated that piperidine substitution at the N3 position and no substitution at N1 position were preferable. Further optimization of the substituents at the piperidine nitrogen and the spacer around the skeleton resulted in several superior antagonists to 1, including 1-adamantanecarbonyl analogue 21i (IC50 = 23 nM in ethidium uptake assay; IC50 = 14 nM in IL-1β ELISA assay) and (3-CF3-4-Cl)benzoyl analogue (-)-21w (54 nM in ethidium uptake assay; 9 nM in IL-1β ELISA assay), which was more potent than the corresponding (+) isomer. Compound 21w displayed potent inhibitory activity in an ex vivo model of LTP-induced pain signaling in the spinal cord and significant anti-inflammatory activity in in vivo models of carrageenan-induced paw edema and type II collagen-induced joint arthritis.

Spontaneous resolution of post-transplant localized cytomegalovirus lymphadenitis mimicking tumor recurrence

Compromised T-cell immunity persists for up to 1 year after autologous stem cell transplantation (ASCT), and patients treated with ASCT are more likely to develop atypical lymphoid hyperplasia that mimics tumor recurrence. Here, we present a case of cervical lymphadenitis due to cytomegalovirus (CMV) reactivation in a patient who had undergone ASCT for Burkitt lymphoma, which mimicked tumor recurrence on computed tomography and positron emission tomography-computed tomography 6 months after ASCT. This lesion was confined to the regional lymph nodes and was not accompanied by signs of systemic involvement, such as fever, splenomegaly, an elevated C-reactive protein level, or viremia. The localized CMV lymphadenitis resolved spontaneously without treatment after 6 months (12 months after ASCT) and the elevated CMV immunoglobulin-M titer normalized 6 months after resolution. Our experience with this case suggests that cautious follow-up without anti-CMV treatment should be considered in cases of post-ASCT localized CMV lymphadenitis without systemic involvement in patients with complete engraftment.

Repeated dosing of piperine induced gene expression of P-glycoprotein via stimulated pregnane-X-receptor activity and altered pharmacokinetics of diltiazem in rats

This study investigated the effect of piperine on the gene expression of P-glycoprotein (P-gp) as well as pregnane-X-receptor (PXR) activity and also its implication on the bioavailability of diltiazem, a P-gp substrate. The effect of piperine on the systemic exposure of diltiazem was examined in rats after the intravenous and oral administration of diltiazem with/without 2 week pretreatment with piperine. Compared with the control group given diltiazem (20 mg/kg) alone, the pretreatment with piperine (10 or 20 mg/kg, once daily for 2 weeks) decreased the oral exposure of diltiazem by 36-48% in rats. Consequently, the bioavailability of oral diltiazem was significantly lower (p < 0.05) after the 2 week pretreatment with piperine. The pretreatment with piperine for 2 weeks also reduced the systemic exposure of desacetyldiltiazem, a major active metabolite of diltiazem by approximately 73%, accompanied by a significant decrease in the metabolite-parent ratio. In contrast to the oral pharmacokinetics, piperine did not affect the intravenous pharmacokinetics of diltiazem in rats. Immunoblot analysis indicated that the protein expression level of intestinal P-gp was significantly enhanced after the 2 week pretreatment with piperine in rats. In addition, piperine increased the PXR reporter activity in human hepatoma cells. Taken together, the 2 week pretreatment with piperine significantly induced intestinal P-gp expression in conjunction with stimulated PXR activity and decreased the oral exposure of diltiazem and desacetyldiltiazem in rats.

Proyl isomerase Pin1 facilitates ubiquitin-mediated degradation of cyclin-dependent kinase 10 to induce tamoxifen resistance in breast cancer cells

Endocrine therapies that inhibit estrogen receptor (ER)-α signaling are the most common and effective treatment for ER-α-positive breast cancer. However, the use of these agents is limited by the frequent development of resistance. The aim of this study was to elucidate the mechanisms by which downregulation of CDK10 expression confers resistance to tamoxifen in breast cancer. Here, we show that peptidyl-prolyl isomerase Pin1 downregulates CDK10 protein as a result of its interaction with and ubiquitination of CDK10, thereby affecting CDK10-dependent Raf-1 phosphorylation (S338). Pin1(-/-) mouse embryonic fibroblasts (MEFs) show higher CDK10 expression than Pin1(+/+) MEFs, whereas CDK10 protein was downregulated in the rescued Pin1(-/-) MEFs after reexpression of Pin1. Pin1 silencing in SKBR-3 and MCF7 cells increased the CDK10 expression. In human tamoxifen-resistant breast cancer and tamoxifen-resistant MCF7 cells, immunohistochemical staining and immunoblotting analysis shows an inverse correlation between the expression of CDK10 and the degree of tamoxifen resistance. There was also a positive correlation between the high level of P-Raf-1 (Ser338) and Pin1 in human tamoxifen-resistant breast cancer and tamoxifen-resistant MCF7 (TAMR-MCF7) cells. Importantly, 4-OH tamoxifen (4-OHT), when used in combination with overexpressed CDK10 or Raf-1 inhibitor, increased cleaved PARP and DNA fragmentation to inhibit cologenic growth of MCF7 cells and Tamoxifen-resistant MCF7 cells, respectively. On the basis of these findings, we suggest that the Pin1-mediated CDK10 ubiquitination is a major regulator of tamoxifen-resistant breast cancer cell growth and survival.

P2-09-13: The Value of FDG PET/CT in Screening Detected Breast Cancer Patients

Background. To evaluate the diagnostic value of FDG PET/CT for initial staging of screening detected breast cancer.

Methods. Between January 2008 and June 2010, a total of 77 women (mean age 54 years, range 31–77 years) with screening detected primary breast cancer (mean invasive tumor size 1.65cm, range 1–70mm) underwent whole body fluorine-18 fluorodeoxyglucose (FDG) PET/CT for initial staging and were included in this retrospective study. Two patients had bilateral breast cancer. The sensitivity of FDG PET/CT for the detection of primary tumor and the sensitivity, specificity, PPV and NPV for the detection of axillary lymph node metastases were determined. Systemic staging with whole body FDG PET/CT was also performed. For analysis of diagnostic performance of FDG PET/CT, quantitative measurement of the maximum standardized uptake value (SUVmax) criteria 1.0 was used. The final histopathology following surgery served as the gold standard.

Results. The primary tumor was FDG PET/CT positive in 65 of 79 lesions (82%). Depending on the tumor size, there was a variation in diagnostic sensitivity (63% in ≤ 1cm tumor, n=19 vs. 88% in &gt; 1cm tumor, n=60) and the uptake of FDG was significantly higher in &gt; 1cm tumor than in ≤ 1cm tumor (mean SUVmax 2.85 vs. 1.11, p&lt;0.05). The uptake of FDG was significantly higher in ductal carcinomas compared to lobular carcinomas (median SUVmax 2.0, n=72 vs. 1.3, n=7, p&lt;0.05). Of the 77 patients included in this study, 16 patients were found to have axillary node metastasis. The sensitivity, specificity, PPV and NPV of FDG PET/CT for detection of LN metastasis were 63% (10/16), 89% (54/61), 59% (10/17) and 90% (54/60), respectively. FDG PET/CT showed distant uptake in 9 patients and 8 of 9 were false positive results. 4 lesions were confirmed histopathologically as benign and 4 lesions were evaluated with radiologic methods. One of nine was true positive result. Distant involvement was skeletal and visible on the conventional bone scintigraphy. The patient staged as cT1N3M1.

Conclusion. FDG PET/CT has limited value for the initial staging of screening detected breast cancer patients. Considering high costs, radiation exposure and false positivity, FDG PET-CT is not recommended for the preoperative evaluation of screening detected breast cancer patients.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-09-13.

Abstract P2-09-01: Serial [18F] FDG-PET after the 2nd Cycle of Preoperative Chemotherapy Is Predictive for Pathological Complete Response in Stage II/III Breast Cancer

Purpose: One of substudies of the prospective trials aimed to evaluate the usefulness of serial [18F] 2-fluoro-2-deoxy-D-glucose-positron emission tomography ([18F] FDG-PET) for predicting pathological complete response (pCR) in stage II/III breast cancer with preoperative chemotherapy (PST).

Methods: Serial PET was undertaken in 57 breast cancer patients enrolled in three different neoadjuvant trials: 35 patients from a phase II study with paclitaxel/gemcitabine/trastuzumab with ClinicalTrial.gov NCT 00532857, 9 patients from a phase Ib study with paclitaxel/gemcitabine/lapatinib with ClinicalTrial.gov NCT 01133912, and 13 patients from a phase Ib with paclitaxel/gemcitabine/sunitinib with ClinicalTrial.gov NCT0 1070706. All patients received 6 cycles of PST followed by surgery and radiotherapy. We assessed the peak standardized uptake value (SUVp) in the primary tumor at the baseline and after the 2nd cycle (37 patients) or after completion (20 patients) of 6 cycles of PST, and calculated the reduction rate (RR) of the SUVp. Pathological response was classified into pCR and non-pCR. To compare the mean of SUVp and RR of SUVp between different response groups, two-way tables and chi-square tests were used

Results: Fifteen (40.6%) of 37 patients who took repeat PET after the 2nd PST and 15 (75%) of 20 patients after completion of PST achieved a pCR with overall pCR rate of 52.6% in the primary tumor. In patients with repeat PET after the 2nd PST, post-treatment SUVp and RR of the SUVp in primary tumors were significantly different by the pathological response (post-treatment SUVp, 1.54 ± 0.63 in pCR vs 2.54 ± 1.06 in non-pCR, P=0.002; RR of the SUVp, 79.2% ± 11.9% in pCR vs 68.9% ± 15.4% in non-pCR, P=0.03). However, in patients with repeat PET after completion of PST, there were no statistical differences of these values (post-treatment SUVp, 1.09 ± 0.63 in pCR vs 1.29 ± 0.36 in non-pCR, P=0.42; RR of the SUVp, 83.7% ± 14.0% in pCR vs 67.5% ± 21.1% in non-pCR, P=0.17)

Conclusions: This study demonstrated that repeat PET after the 2nd cycle of PST, not after completion of PST could predict pCR in stage II/III breast cancer with preoperative chemotherapy. Acknowledgement NCC Grant #0910320.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-09-01.

The prolyl isomerase Pin1 interacts with a ribosomal protein S6 kinase to enhance insulin-induced AP-1 activity and cellular transformation

Phosphorylation of proteins on serine or threonine residues that immediately precede proline (pSer/Thr-Pro) is specifically catalyzed by the peptidyl-prolyl cis-trans isomerase Pin1 and is a central signaling mechanism in cell proliferation and transformation. Although Pin1 is frequently overexpressed in hepatocellular carcinoma (HCC), the molecular mechanism of Pin1 in HCC has not been completely elucidated. Here, we show that Pin1 interacts with p70S6K in vitro and ex vivo. Overexpression of Pin1 resulted in enhanced p70S6K phosphorylation induced by insulin in SK-HEP-1 cells. In contrast, Pin1(-/-) mouse embryonic fibroblasts (MEFs) exhibited significantly decreased insulin-induced p70S6K phosphorylation compared with Pin1(+/+) MEFs. Furthermore, Pin1 enhanced the insulin-induced extracellular signal-regulated protein kinase (ERK)1/2 phosphorylation through its interaction with p70S6K, whereas the inhibition of p70S6K activity by rapamycin suppressed insulin-induced ERK1/2 phosphorylation in SK-HEP-1 cells. Hence, Pin1 affected activator protein-1 activity through p70S6K-ERK1/2 signaling in SK-HEP-1 cells. Most importantly, Pin1-overexpressing JB6 Cl41 cells enhanced neoplastic cell transformation promoted by insulin much more than green fluorescent protein-overexpressing JB6 Cl41 control cells. These results imply that Pin1 amplifies insulin signaling in hepatocarcinoma cells through its interaction with p70S6K, suggesting that Pin1 plays an important role in insulin-induced tumorigenesis and is a potential therapeutic target in hepatocarcinoma.

Role of FoxO1 activation in MDR1 expression in adriamycin-resistant breast cancer cells

The development of multidrug resistance 1 (MDR1) can be mediated by a number of different mechanisms but elevated gene expression of MDR1 (P-glycoprotein) has often been a major cause of chemoresistance in many cancer cells. Therefore, the present study aimed to investigate the role of forkhead box-containing protein, O subfamily (FoxO), transcription factors in regulating the MDR1 gene expression. The proximal promoter region of the human MDR1 contained a putative FoxO-binding site, which partially overlapped with the enhancer/enhancer-binding protein beta-binding region. Gel shift and immunoblot analysis of subcellular fractions revealed that nuclear levels of FoxO1 and its DNA-binding activity were selectively enhanced in MCF-7/ADR cells, which was reversed by a FoxO1 antibody. Reporter gene assays showed that the transcription of MDR1 gene is stimulated by FoxO1 overexpression. Moreover, both MDR1 expression and doxorubicin resistance in MCF-7/ADR cells were reversed by FoxO1 small interfering RNA (siRNA). The MDR1 expression in MCF-7/ADR cells was also inhibited by insulin, a functional FoxO1 inactivator. In conclusion, FoxO1 is a novel transcriptional activator of MDR1 and is crucial for MDR1 induction in MCF-7/ADR cells.

Ginsenoside Rd enhances glutathione levels in H4IIE cells via NF-kappaB-dependent gamma-glutamylcysteine ligase induction

Panax ginseng is widely used as herbal medicine in East Asia and the pharmacological effects of P. ginseng against certain chronic diseases might be explained by its antioxidative effects. Here, we show that ginsenoside Rd significantly increases both cellular glutathione (GSH) contents and the protein level of gamma-glutamylcysteine ligase (gamma-GCL) heavy chain in H4IIE cells (a rat hepatocyte cell line). Subcellular fractionation and Western blot analysis revealed that ginsenoside Rd increased the nuclear level of p65, but not of Nrf2. Moreover, ginsenoside Rd increased luciferase reporter gene activity in cells transfected with nuclear factor-kappaB (NF-kappaB) binding site-containing -1088 bp gamma-GCL promoter. However, ginsenoside Rd-inducible reporter activity was abolished when cells were transfected with NF-kappaB deletion mutant. These effectsof ginsenoside Rd are suggested to underlie the putative anti-oxidative effect of Panax ginseng.

Mandibular symphyseal distraction osteogenesis with stepwise osteotomy in adult skeletal class III patient

This technical note reports the use of symphyseal distraction with stepwise osteotomy in a case of lower anterior crowding and rotation in the incisor area. This technique allows for easy dental decompensation and reduced presurgical orthodontic time in skeletal class III cases.

Altered neural circuit for working memory before and after symptom provocation in patients with obsessive-compulsive disorder

OBJECTIVE

The authors compared the neural circuits recruited for working memory (WM) in obsessive-compulsive disorder (OCD) patients both at a neutral state and at a symptom provoked state.

METHOD

Twelve OCD patients, and 12 age-, and sex-matched healthy subjects underwent [(15)O]H(2)O positron emission tomography (PET) scanning, while performing WM task. In the patients, the tasks were performed both in the neutral and in the symptom provoked states.

RESULTS

In the OCD patients, the right caudate and the right superior parietal cortex (rSPC) displayed activations for WM at the neutral state, while the right cingulate cortex and rSPC displayed activations for WM at the symptom provoked state. Path analysis revealed that the activity of the caudate and orbitofrontal cortex was altered according to the interaction between WM and symptom provocation.

CONCLUSION

The interaction between symptom provocation and WM occurring in the fronto-striatal system may hold the key to the neurobiology of OCD.

Screening of new chemopreventive compounds from Digitalis purpurea

Chemopreventive agents induce a battery of genes whose protein products can protect cells from chemical-induced carcinogenesis. In this study, we isolated four different glycosides (1 acteoside; 2 purpureaside A; 3 calceolarioside B; and 4, plantainoside D) from the leaves of Digitalis purpurea and studied their abilities to induce glutathione S-transferase (GST) and their protective efficiencies against aflatoxin B1-induced cytotoxicity in H4IIE cells. Of these four glycosides, acteoside significantly inhibited the cytotoxicity induced by aflatoxin B1 (AFB1) and also selectively increased GSTalpha protein levels. Reporter gene analysis using an antioxidant response element (ARE) containing construct and subcellular fractionation assays, revealed that GSTalpha induction by acteoside might be associated with Nrf2/ARE activation. The results suggest that acteoside possesses a potent hepatoprotective effect against AFB1 and that it can be applied as a potential chemopreventive agent.

Amentoflavone inhibits the induction of nitric oxide synthase by inhibiting NF-κB activation in macrophages

Amentoflavone is a bi-flavonoid compound with anti-fungal and anti-inflammatory activities. We isolated amentoflavone from Selaginella tamariscina (Selaginellaceae) and studied its effects on nuclear factor-kappaB (NF-kappaB)-mediated inducible nitric oxide synthase (iNOS) gene expression in RAW 264.7 cells. Amentoflavone inhibited the production of nitric oxide in a concentration-dependent manner and also blocked the lipopolysaccharide (LPS)-induced expression of inducible nitric oxide synthase (iNOS). To clarify the mechanistic basis for its inhibition of iNOS induction, we examined the effect of amentoflavone on the transactivation of iNOS gene by luciferase reporter activity using -1.59 kb flanking region. Amentoflavone potently suppressed the reporter gene activity. The LPS-induced activation of NF-kappaB was also found to be significantly blocked by amentoflavone, but AP-1 activation was unaffected. Furthermore, the nuclear translocation of p65 by LPS was inhibited by amentoflavone. NF-kappaB activation is controlled by the phosphorylation and subsequent degradation of I-kappaBalpha, and the cytosolic degradation of I-kappaBalpha was found to be inhibited by amentoflavone. These findings suggest that the inhibition of LPS-induced NO formation by amentoflavone is due to its inhibition of NF-kappaB by blocking I-kappaBalpha degradation, which may be the mechanistic basis of the anti-inflammatory effects of amentoflavone.

Somatic mutation of p53 leads to estrogen receptor alpha-positive and -negative mouse mammary tumors with high frequency of metastasis

Approximately 70% of human breast cancers are estrogen receptor alpha (ERalpha)-positive, but the origins of ERalpha-positive and -negative tumors remain unclear. Hormonal regulation of mammary gland development in mice is similar to that in humans; however, most mouse models produce only ERalpha-negative tumors. In addition, these mouse tumors metastasize at a low rate relative to human breast tumors. We report here that somatic mutations of p53 in mouse mammary epithelial cells using the Cre/loxP system leads to ERalpha-positive and -negative tumors. p53 inactivation under a constitutive active WAPCre(c) in prepubertal/pubertal mice, but not under MMTVCre in adult mice, leads to the development of ERalpha-positive tumors, suggesting that target cells or developmental stages can determine ERalpha status in mammary tumors. Importantly, these tumors have a high rate of metastasis. An inverse relationship between the number of targeted cells and median tumor latency was also observed. Median tumor latency reaches a plateau when targeted cell numbers exceed 20%, implying the existence of saturation kinetics for breast carcinogenesis. Genetic alterations commonly observed in human breast cancer including c-myc amplification and Her2/Neu/erbB2 activation were seen in these mouse tumors. Thus, this tumor system reproduces many important features of human breast cancer and provides tools for the study of the origins of ERalpha-positive and -negative breast tumors in mice.

Effects of cyclo (his-pro) plus zinc on glucose metabolism in genetically diabetic obese mice

AIMS

The specific objective of this study was to determine acute and long-term effects of cyclo (his-pro) (CHP) plus zinc and l-histidine (CZH) treatment on glucose metabolism in genetically obese (ob/ob), type 2 diabetic mice.

METHODS

Acute effects of 0.3 mg of CHP plus 10 mg of zinc and 0.5 mg of l-histidine/kg body weight (BW) on fed blood glucose concentrations and 3-h average of above fasting blood glucose concentrations (TAFGCs), an index of oral glucose tolerance test, in lean and ob/ob mice were determined. To evaluate long-term effects of CZH on TAFGCs, lean and ob/ob mice were treated with drinking water containing increasing doses of CHP (0, 0.5, 1.0 or 1.5 mg/l) plus 10 mg zinc and 0.5 mg of l-histidine/l for 3 weeks. During the treatment period, fed blood glucose concentrations, BW and food and water intake were determined. At the end of the treatment, fasting blood glucose concentrations, TAFGC and fed plasma insulin concentrations were determined.

RESULTS

Blood glucose concentrations significantly decreased when CZH was administered acutely via gastric gavage in food-deprived ob/ob mice. Similarly, 1.0 mg/l CHP treatment of mice with fixed amounts of 10 mg zinc and 0.5 mg l-histidine/l was optimal to decrease fed blood glucose and plasma insulin concentrations during a 3-week treatment period in ob/ob mice. TAFGC values in these mice also improved most significantly with the same combination of CHP, zinc and l-histidine used to test for fed blood glucose and plasma insulin levels. Fasting blood glucose concentrations and BW gains also decreased in ob/ob mice treated with 1.0 mg of CHP/l plus the same amount of zinc and l-histidine used in the above experiments. No effects of CZH treatment in lean mice were observed.

CONCLUSIONS

CZH is effective in decreasing blood glucose concentrations in genetically obese (ob/ob), type 2 diabetic mice. These data support our working hypothesis that CZH may be an important anti-hyperglycaemic agent.

Induction of hepatic inducible nitric oxide synthase by cholesterol in vivo and in vitro

Cholesterol-rich diet impairs endothelial NO synthase (eNOS) and enhances inducible NOS (iNOS) expression. In this study, we investigated effects of cholesterol on iNOS expression in high-fat-fed rat models, HepG2 and RAW264.7 cells. The high-fat diet increased the plasma total cholesterol level 6-7 fold and low-density lipoprotein cholesterol level (LDL-C) approximately 70 fold and slightly increased the level of lipid peroxidation as determined by thiobarbituric acid-reactive substance assay. The high-fat diet also increased plasma nitric oxide (NO) concentrations up to 5 fold, and induced iNOS mRNA expression in liver. The contractile responses of the endothelium-denuded thoracic aortic rings to phenylephrine were significantly damaged in high-fat-fed rats when assessed by organ chamber study. Treatment with estrogen for 4 days failed to reduce iNOS expressions as well as aortic contractility, although it improved lipid profiles. In cultured HepG2 or murine macrophage RAW264.7 cells, 3 days treatment with either 25-hydroxycholesterol or 7-ketocholesterol induced iNOS mRNA expression, as determined by RT-PCR. Our data suggested that the chronic exposure of hepatocytes and macrophage cells to high concentration of cholesterol or oxysterols may induce iNOS expression and subsequent synthesis of NO, which may be important in the pathogenesis of atherosclerosis.

Diagnostic performance of [18F]FDG-PET and ictal [99mTc]-HMPAO SPECT in occipital lobe epilepsy

PURPOSE

We investigated whether interictal F-18 fluorodeoxyglucose positron emission tomography ([18F]FDG-PET) or ictal [99mTc]-HMPAO single-photon emission computed tomography (SPECT) was useful to find epileptogenic zones in occipital lobe epilepsy (OLE).

METHODS

We reviewed visually and quantified patterns of hypometabolism in interictal [18F]FDG-PET and those of hyperperfusion in ictal SPECT in 17 OLE patients (27 plus minus 6.8 years old; M/F, 10/7; injection time, 30 plus minus 17 s). OLE was diagnosed based on invasive electroencephalography, surgery, and postsurgical outcome (Engel class I in all at an average of 26 months after surgery).

RESULTS

Epileptogenic zones were correctly localized in nine (60%) of 15 patients by interictal [18F]FDG-PET, and asymmetric indices corroborated visual diagnosis. Epileptogenic hemispheres were correctly lateralized in 14 (93%) of 15 patients on [18F]FDG-PET. Epileptogenic hemispheres were correctly lateralized in 13 (76%) of 17 patients using ictal SPECT, but localization was possible in only five (29%) patients. Interictal [18F]FDG-PET was helpful in two of the patients who showed no abnormality on magnetic resonance imaging (MRI) and no possible localization with ictal SPECT.

CONCLUSIONS

In OLE, ictal SPECT was helpful in lateralization, but less helpful in localization. Interictal [18F]FDG-PET was helpful in localization or lateralization of epileptogenic zones, even in patients with ambiguous MRI or ictal SPECT findings.

Disparity of perfusion and glucose metabolism of epileptogenic zones in temporal lobe epilepsy demonstrated by SPM/SPAM analysis on 15O water PET, [18F]FDG-PET, and [99mTc]-HMPAO SPECT

PURPOSE

To elucidate uncoupling of perfusion and metabolism and its significance in epilepsy, 15O water and 18F fluorodeoxyglucose (FDG) positron emission tomography (PET) and Tc-99m hexamethyl-propyleneamine-oxime (HMPAO) single-photon emission computed tomography (SPECT) were examined by SPM (statistical parametric mapping) and quantitation by using SPAM (statistical probabilistic anatomic map).

METHODS

[15O]water and [18F]FDG-PET, and [99mTc]-HMPAO SPECT were performed in 25 patients (SPECT in 17 of 25) with medial temporal lobe epilepsy. For volume of interest (VOI) count analysis, the normalized counts using VOI based on SPAM templates of PET and SPECT were compared with those of the normal controls. Perfusion or metabolism was found abnormal if the Z score was >2 for each VOI. For SPM analysis, the differences between each patient's image and a group of normal control images (t statistic for p < 0.01) on a voxel-by-voxel basis were examined to find significant decreases in perfusion or metabolism.

RESULTS

With SPAM VOI count analysis, areas of hypoperfusion were found in 13 patients in the epileptogenic temporal lobes by [15O]water PET and areas of hypometabolism in 21 patients by [18F]FDG-PET. With voxel-based SPM analysis, the epileptogenic zones were localized in 15 by [15O]water PET and in 23 patients by [18F]FDG-PET. The localization by [15O]water PET was concordant with that of [18F]FDG-PET. The areas of hypoperfusion on [15O]water PET were absent or smaller than the areas of hypometabolism on [18F]FDG-PET. Interictal [99mTc]-HMPAO SPECT revealed the hypoperfused zones in seven of 17 patients on visual assessment.

CONCLUSIONS

SPAM VOI count and SPM analysis of [15O]water and [18F]FDG-PET and [99mTc]-HMPAO SPECT revealed that in the same patients, the areas of hypoperfusion were concordant with but smaller than the areas of hypometabolism. Discordance of perfusion and metabolic abnormalities represents an uncoupling of perfusion and metabolism in the epileptogenic zones, and this might explain the lower diagnostic accuracy of perfusion imaging in temporal lobe epilepsy.

Potentiation of cadmium-induced cytotoxicity by sulfur amino acid deprivation through activation of extracellular signal-regulated kinase1/2 (ERK1/2) in conjunction with p38 kinase or c-jun N-terminal kinase (JNK). Complete inhibition of the potentiated toxicity by U0126 an ERK1/2 and p38 kinase inhibitor

The mechanisms of cadmium-induced toxicity may include oxidative stress, altered redox homeostasis, and injuries to organelles. The current study was designed to study the effect of decreased cellular glutathione (GSH) content by sulfur amino acid deprivation on cadmium toxicity and to identify the signaling pathways responsible for the cytotoxicity. GSH content was increased by cadmium in H4IIE cells prior to cell death, which was prevented by excess GSH or cysteine. Cell viability, however, was not improved by GSH or cysteine complexation of cadmium. Cadmium-induced cytotoxicity was 40-fold potentiated in cells with decreased GSH by sulfur amino acid deprivation. Cadmium in combination with decreased GSH markedly increased apoptotic cell death. Mitogen-activated protein kinases including extracellular signal-regulated kinase 1/2, p38 kinase and c-Jun N-terminal kinase (JNK) were all activated 1-12 hr after sulfur amino acid deprivation. U0126 (1,4-diamino-2,3-dicyano-1,4-bis[2-aminophenylthio]butadiene), which inhibited activation of extracellular signal-regulated kinase1/2 and p38 kinase in cells under sulfur amino acid deprivation, completely prevented potentiation in Cd-induced cytotoxicity and apoptosis. Potentiation of cadmium toxicity by sulfur amino acid deprivation was prevented in part by either PD98059 or SB203580, or in cells stably expressing dominant negative mutant of JNK1, and to greater extents by PD98059 in combination with either SB203580 or JNK1(-) transfection. These results demonstrated that decreased cellular GSH content potentiated cytotoxicity induced by cadmium at the level of human exposure, and that the potentiation of cytotoxicity resulted from activation of extracellular signal-regulated kinase1/2 in conjunction with p38 kinase or JNK.

Domain and genomic sequence analysis of bdellin-KL, a leech-derived trypsin-plasmin inhibitor

Bdellin-KL is a trypsin-plasmin inhibitor from Hirudo nipponia, whose N-terminal sequence was identified as a non-classical Kazal-type. A cDNA clone encoding the inhibitor was isolated by reverse transcription-PCR and 5' rapid amplification of cDNA ends. The cDNA showed an open reading frame of 155 amino acids comprising one signal peptide and two separated domains. The C-terminal domain consists of distinct internal repeats, including HHEE and HHDD. The bdellin-KL sequence, from the constructed genomic library of Korean leech, was determined for the 2109 bases comprising the open reading frame and flanking regions (3' and 5'). The promoter region contains potential regulatory sequence motifs, including TATA, CAAT, and GC boxes. To characterize the properties of each domain, an N-terminal fragment was prepared by limited proteolysis of the intact protein. The inhibitory activity of the region was as potent as that of the intact protein. This suggests that the compact domain plays an important part in the inhibitory action of bdellin-KL. The C-terminal domain was revealed to have binding affinity to ions such as Ca(2+), Zn(2+), Fe(3+), and Fe(2+) without an influence on the inhibitory activity. This study demonstrates that bdellin-KL may be a novel bifunctional protein with two distinct domains.

Quantification of F-18 FDG PET images in temporal lobe epilepsy patients using probabilistic brain atlas

A probabilistic atlas of the human brain (Statistical Probabilistic Anatomical Maps: SPAM) was developed by the international consortium for brain mapping (ICBM). It is a good frame for calculating volume of interest (VOI) in many fields of brain images. After calculating the counts in VOI using the product of probability of SPAM images and counts in FDG images, asymmetric indices (AI) were calculated and used for finding epileptogenic zones in mesial temporal lobe epilepsy (mTLE). FDG PET images from 18 surgically confirmed mTLE patients and 22 age-matched controls were spatially normalized to the average brain MRI template of ICBM. Counts from normalized PET images were multiplied with the probability of 12 VOIs from SPAM images in both temporal lobes. Finally AI were calculated on each pair of VOIs, and compared with visual assessment. If AI of mTLE patients were not within 2.9 standard deviation from those of normal control group (P < 0.008; Bonferroni correction for P < 0.05), epileptogenic zones were considered to be found successfully. The counts of VOIs in the normal control group were symmetric (AI < 4.3%, paired t test P > 0.05) except for those of the inferior temporal gyrus (P < 0.001). By AIs in six pairs of VOIs, PET in mTLE had deficit on one side (P < 0.05). Lateralization was correct in only 14/18 of patients by AI, but 17/18 were consistent with visual inspection. In three patients with normal AI, PET images were symmetric on visual inspection. The asymmetric indices obtained by taking the product of the statistical probability anatomical map and FDG PET, correlated well with visual assessment in mTLE patients. SPAM is useful for the quantification of VOIs in functional images.

2-(Allylthio)pyrazine, a cancer chemopreventive agent, inhibits liver fibrosis induced by dimethylnitrosamine in rats: role of inhibition of transforming growth factor-beta1 expression

Exposure to nitrosamines may be the occupational risk factor for liver cirrhosis. 2-(Allylthio)pyrazine, a chemopreventive agent, inhibits CYP2E1 and induces phase II enzymes. We examined the effects of 2-(allylthio)pyrazine on hepatic fibrosis, a prepathologic state of cirrhosis, and on the expression of transforming growth factor-beta1 induced by dimethylnitrosamine. Treatment of rats with dimethylnitrosamine for 4 weeks increased plasma alanine/aspartate amino-transferase and y-glutamyl transpeptidase activities, and bilirubin content, whereas the total plasma protein and albumin levels were decreased. 2-(Allylthio)pyrazine inhibited dimethylnitrosamine-induced increases in the enzyme activities and bilirubin, and restored the plasma protein and albumin contents. Masson's trichrome staining showed that dimethylnitrosamine induced liver fibrosis, the extent of which was reduced by 2-(allylthio)pyrazine treatments. Reverse transcription-polymerase chain reaction analysis revealed that 2-(allylthio)pyrazine inhibited production of transforming growth factor-beta1 mRNA by dimethylnitrosamine. These results demonstrated that 2-(allylthio)pyrazine might inhibit dimethylnitrosamine-induced liver fibrosis due to suppression of CYP2E1 expression and transforming growth factor-beta1 production.

Activation of phosphatidylinositol 3-kinase by oxidative stress leads to the induction of microsomal epoxide hydrolase in H4IIE cells

We have shown that PI3-kinase played an essential role in the ARE-mediated rGSTA2 induction by oxidative stress following SAAD (Mol. Pharmacol. 58 (2000) 1017). Microsomal epoxide hydrolase (mEH), which detoxifies a variety of epoxide intermediates produced from various xenobiotics, is inducible by oxidative stress. In the present study, we studied whether sulfur amino acid deprivation (SAAD) activated phosphatidylinositol 3-kinase (PI3-kinase)/Akt and induced mEH in H4IIE cells. The role of PI3-kinase activation on the mEH induction by SAAD was also investigated. PI3-kinase was activated from 10 min through 12 h after SAAD, the activity of which returned to control level at 24 h. The activation of PI3-kinase led to increases in the activity of Akt at the same time points. Northern and Western blot analyses revealed that the mEH mRNA level was four-fold increased at 48 h, which accompanied the induction of mEH protein. Wortmannin or LY294002, PI3-kinase inhibitors, completely inhibited the increases in mEH mRNA and protein by SAAD. These results demonstrated that SAAD activated the PI3-kinase/Akt pathway at early stages and induced mEH, presumably as an adaptive response, and that the PI3-kinase/Akt pathway played a crucial role in the induction of mEH.

DA-125, a novel anthracycline derivative showing high-affinity DNA binding and topoisomerase II inhibitory activities, exerts cytotoxicity via c-Jun N-terminal kinase pathway

PURPOSE

DA-125 [(8S,10S)-8-(3-Aminopropanoyloxyacetyl)-10-[(2,6-dideoxy-2-fluoro-alpha-L-talopyranosyl) oxy]-7,8,9,10-tetrahydro-6,8,11-trihydroxy-1-methoxy-5,12-naphthacene-dione hydrochloride] is a novel anthracycline derivative with anticancer activity. In the present study, we compared the cytotoxicity of DA-125 with that of doxorubicin in H4IIE rat hepatoma cells and investigated the mechanistic basis. Because activation of MAP kinases, in particular c-Jun N-terminal kinase (JNK), is implicated in apoptotic cell death, the signaling pathways responsible for DA-125-induced apoptosis were studied.

METHODS

Cytotoxicity and apoptosis were measured in H4IIE cells and cells were stably transfected with a dominant-negative mutant of JNK1 (JNK1-) by MTT and TUNEL assays. Inhibition of topoisomerase II activity was determined in vitro. Drug accumulation and DNA binding affinity were determined by fluorescence spectroscopy.

RESULTS

The cytotoxicity of DA-125 was greater than that of doxorubicin (IC50 11.5 vs 70 microM). DA-125 induced apoptosis with 30-fold greater potency than doxorubicin. Inhibition of topoisomerase II by DA-125 was fourfold greater. The presence of excess beta-alanine, a DA-125 moiety, failed to alter cytotoxicity and accumulation of DA-125, indicating that the improved cytotoxicity of DA-125 did not result from the beta-alanine moiety. Greater cellular accumulation of DA-125 correlated with its high-affinity DNA binding. Although neither PD98059 nor SB203580 altered the degree of cytotoxicity induced by DA-125, JNK1 cells exhibited about a twofold greater viability than control cells. DA-125-induced apoptosis was also decreased in JNK1- -transfected cells.

CONCLUSIONS

DA-125 potently inhibited topoisomerase II activity and induced apoptosis by a high rate of prooxidant production. DA-125 exhibited high-affinity DNA binding with improved cellular drug accumulation. Apoptosis induced by DA-125 involved the pathway of JNK1, but not ERK1/2 or p38 kinase.

Activation of phosphatidylinositol 3-kinase and Akt by tert-butylhydroquinone is responsible for antioxidant response element-mediated rGSTA2 induction in H4IIE cells

The protective adaptive response to electrophiles and reactive oxygen species is mediated by enhanced expression of phase II detoxifying genes, including glutathione S-transferases, through activation of antioxidant response element (ARE). The current study was designed to investigate the role of phosphatidylinositol 3-kinase (PI3-kinase)-Akt and mitogen-activated protein (MAP) kinase signaling pathways in the induction of rGSTA2 by tert-butylhydroquinone (t-BHQ). Nuclear ARE complex was activated 1 to 6 h after treatment of H4IIE cells with t-BHQ. The rGSTA2 mRNA level was elevated 6 to 24 h after t-BHQ treatment, which led to the enzyme induction. Activities of PI3-kinase and Akt were increased 10 min through 6 h after t-BHQ treatment, whereas wortmannin or LY294002, PI3-kinase inhibitors, completely abolished ARE binding activity and increases in rGSTA2 mRNA and protein. Extracellular signal-regulated kinase (ERK), p38 MAP kinase, and c-Jun N-terminal kinase (JNK) were all activated by t-BHQ. Treatment with PD98059, an ERK inhibitor, however, increased rGSTA2 mRNA and further enhanced t-BHQ-induced expression of rGSTA2. Neither SB203580 nor overexpression of JNK1 dominant negative mutant altered t-BHQ-inducible rGSTA2 expression. These results demonstrated that t-BHQ activated PI3-kinase and Akt, which was responsible for ARE-mediated rGSTA2 induction, and that ERK might negatively regulate rGSTA2 expression, whereas activation of p38 MAP kinase or of JNK by t-BHQ was not associated with the enzyme induction.

Glutathione S-transferase mu modulates the stress-activated signals by suppressing apoptosis signal-regulating kinase 1

Apoptosis signal-regulating kinase 1 (ASK1) is a mitogen-activated protein kinase kinase kinase that can activate the c-Jun N-terminal kinase and the p38 signaling pathways. It plays a critical role in cytokine- and stress-induced apoptosis. To further characterize the mechanism of the regulation of the ASK1 signal, we searched for ASK1-interacting proteins employing the yeast two-hybrid method. The yeast two-hybrid assay indicated that mouse glutathione S-transferase Mu 1-1 (mGSTM1-1), an enzyme involved in the metabolism of drugs and xenobiotics, interacted with ASK1. We subsequently confirmed that mGSTM1-1 physically associated with ASK1 both in vivo and in vitro. The in vitro binding assay indicated that the C-terminal portion of mGSTM1-1 and the N-terminal region of ASK1 were crucial for binding one another. Furthermore, mGSTM1-1 suppressed stress-stimulated ASK1 activity in cultured cells. mGSTM1-1 also blocked ASK1 oligomerization. The ASK1 inhibition by mGSTM1-1 occurred independently of the glutathione-conjugating activity of mGSTM1-1. Moreover, mGSTM1-1 repressed ASK1-dependent apoptotic cell death. Taken together, our findings suggest that mGSTM1-1 functions as an endogenous inhibitor of ASK1. This highlights a novel function for mGSTM1-1 insofar as mGSTM1-1 may modulate stress-mediated signals by repressing ASK1, and this activity occurs independently of its well-known catalytic activity in intracellular glutathione metabolism.

Potentiation of arsenic-induced cytotoxicity by sulfur amino acid deprivation (SAAD) through activation of ERK1/2, p38 kinase and JNK1: the distinct role of JNK1 in SAAD-potentiated mercury toxicity

Sulfur amino acid deficiency occurs in certain pathophysiological situations (e.g. protein-calorie malnutrition). Previous studies revealed that sulfur amino acid deprivation (SAAD) activated MAP kinases and potentiated cadmium-induced cytotoxicity by activation of ERK1/2 in conjunction with p38 kinase or JNK. The present study was designed to determine susceptibility of cells to a variety of heavy metals in combination with SAAD. Viability was assessed in H4IIE cells treated with sodium arsenite, mercuric chloride, sodium selenite, lead acetate, chromium trioxide or manganese chloride. SAAD potentiated the cytotoxicity of H4IIE cells by arsenic or mercury (i.e. EC50, 19 and 5 microM in SAAD vs. 401 and 42 microM in control medium, respectively). TUNEL assays revealed that the potentiated arsenic or mercury toxicity involved apoptotic cell death. Lead or selenite moderately elicited cell death, which was not enhanced by SAAD. Chromium or manganese caused no significant cytotoxicity. Treatment of cells with U0126 [1,4-diamino-2,3-dicyano-1,4-bis(2-aminophenylthio)butadiene] an ERK1/2 inhibitor or SB203580 [4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-imidazole] a p38 kinase inhibitor effectively prevented SAAD-potentiated arsenic toxicity. The potentiated arsenic toxicity was also inhibited in cells stably expressing a dominant negative mutant of c-Jun N-terminal kinase 1 [JNK1(-)]. The inhibitors of extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 kinase failed to prevent mercury-induced toxicity enhanced by SAAD. JNK1(-) cells were minimally susceptible to mercury in SAAD medium. These results demonstrated that SAAD potentiated cytotoxicity induced by arsenic or mercury and that activation of ERK1/2, p38 kinase and JNK1 was responsible for the potentiated arsenic toxicity, whereas the mercury toxicity enhanced by SAAD was mediated with the activity of JNK1.

ctr1, a gene involved in a signal transduction pathway of the gliding motility in the cyanobacterium Synechocystis sp. PCC 6803

We generated random Tn5 mutations in Synechocystis sp. PCC 6803 in search for genes involved in the signal transduction cascade for the cyanobacterial gliding motility. One of the non-gliding Tn5 mutants, S1-105, had an insertional inactivation in the slr1044 gene encoding a putative methyl-accepting chemotaxis protein. Interposon mutation on the slr1044 (named ctr1) in the bacterium also eliminated gliding motility. In the interposon mutant, the expression of pilA1 was 5-fold decreased compared with that of wild-type and thick pili, that are believed to be the motor for gliding, could not be observed by an electron microscope. Therefore, we suggest that the Ctr1 protein functions as a transducer that regulates the expression of pilA1, and thus is required for the biogenesis of thick pili.

The essential role of phosphatidylinositol 3-kinase and of p38 mitogen-activated protein kinase activation in the antioxidant response element-mediated rGSTA2 induction by decreased glutathione in H4IIE hepatoma cells

The protective adaptive response to electrophiles and reactive oxygen species is mediated by the enhanced expression of the phase II detoxifying genes through antioxidant response elements (AREs). The current study was designed to identify the signaling pathways responsible for the expression of rGSTA2 in response to cellular oxidative stress and to establish the molecular mechanistic basis. Deprivation of cystine and methionine caused oxidative stress in H4IIE hepatoma cells as evidenced by a marked decrease in the reduced glutathione (first order rate constant = 0.056 h(-1); t(1/2) = 12.6 h) and an increase in pro-oxidant production. Electrophoretic mobility shift assay revealed that the ARE complex, consisting of Nrf-1/2 and Maf proteins, was activated 12 to 48 h after sulfur amino acid deprivation (SAAD). The rGSTA2 mRNA level was elevated by SAAD beginning at 24 h, whereas the rGSTA2 subunit was maximally induced at 48 h. Nuclear ARE activation and rGSTA2 mRNA increase were both completely inhibited by wortmannin or LY294002, the phosphatidylinositol 3-kinase (PI3-kinase) inhibitors. The p38 mitogen-activated protein (MAP) kinase was activated at 0.5 to 3 h after SAAD, followed by sustained diminished activation up to 12 h. Inhibition of p38 MAP kinase by SB203580 prevented the ARE-mediated rGSTA2 induction. The activation of p38 MAP kinase, however, failed to be inhibited by wortmannin or LY294002, showing that PI3-kinase is not involved in the activation of p38 MAP kinase. Data showed that PI3-kinase plays an essential role in the ARE-mediated rGSTA2 induction by oxidative stress after SAAD, which activates the p38 MAP kinase and leads to rGSTA2 induction.

Production and characterization of recombinant guamerin, an elastase-specific inhibitor, in the methylotrophic yeast Pichia pastoris

The elastase-specific inhibitor, guamerin, was expressed and secreted into a culture medium using the methylotrophic yeast Pichia pastoris, and the resulting recombinant guamerin was purified from the culture media using a two-step procedure composed of a hydrophobic interaction and reverse-phase chromatography. Up to 90 g/L of dry cell weight, the guamerin-producing recombinant P. pastoris was cultivated and guamerin was secreted into the culture medium at a level of 0.69 g/L. The recombinant guamerin was highly purified (>98%) with a recovery yield of 68%. Analyses of the purified guamerin revealed the same N-terminal amino acid sequence, amino acid composition, and molecular mass as found in the native leech protein. The recombinant guamerin exhibited the tight binding to porcine pancreatic elastase. Furthermore, the recombinant guamerin did not produce a humoral immune response in mice.

Late postictal residual perfusion abnormality in epileptogenic zone found on 6-hour postictal SPECT

BACKGROUND

Temporal evolution of regional hyperperfusion in the late postictal stage in epilepsy has not been clearly defined.

OBJECTIVE

To establish the late temporal evolution of the perfusion in epileptogenic zones using 6-hour postictal SPECT.

METHODS

Ictal 99mTc-hexamethylpropyleneamine oxime (99mTc-HMPAO) SPECT was performed in 10 patients with intractable epilepsy (4 temporal lobe epilepsy, 6 neocortical epilepsy) followed by delayed acquisition and another 6-hour postictal SPECT after reinjection of 99mTc-HMPAO. The delayed acquired SPECT was subtracted from the reinjection SPECT to yield the 6-hour postictal SPECT. Interictal SPECT was acquired on another day. Late postictal perfusion was examined visually, and asymmetric indexes were compared with each other on ictal, 6-hour postictal, and interictal SPECT.

RESULTS

Ictal SPECT images of delayed acquisition were visually and quantitatively similar to those of early acquisition. In 7 of 10 patients, 6-hour postictal SPECT showed hyperperfusion. In one patient, the 6-hour postictal SPECT image showed less perfusion than the interictal SPECT image in the epileptogenic zone.

CONCLUSIONS

Late postictal hyperperfusion was found in more than half of the patients. Postictal perfusion abnormalities did not come back to the interictal phase 6 hours after ictus and these were identified on ictal/postictal 99mTc- HMPAO SPECT.

Partial liquid ventilation shows dose-dependent increase in oxygenation with PEEP and decreases lung injury associated with mechanical ventilation

PURPOSE

The purpose of this article is to evaluate the effect of positive end-expiratory pressure (PEEP) during partial liquid ventilation (PLV) and to investigate if lung damage associated with mechanical ventilation can be reduced by PLV.

MATERIALS AND METHODS

Twenty-two New-Zealand white rabbits were ventilated in pressure-controlled mode maintaining constant tidal volume (10 mL/kg). Lung injury was induced by repeated saline lavage (PaO2 < 100 mm Hg). Two incremental PEEP steps maneuvers (IPSMs) from 2 to 10 cm H2O in 2 cm H2O steps were performed sequentially. The control group received the first IPSM in the supine position and were turned prone for the second IPSM. In the PLV group (n = 7), 12 mL/kg of perfluorodecalin was instilled after lung injury before the two IPSMs. The early prone group (n = 7) received both IPSMs in the prone position. Parameters of gas exchange, lung mechanics, and hemodynamics as well as pathology were examined.

RESULTS

During the first IPSM, the PLV group showed a significant increase in PaO2 after instillation of perfluorodecalin (P < .05) and then showed a dose-dependent increase in PaO2 with PEER. The control and EP groups showed improvement in PaO2 only at higher PEEP, eventually showing no intergroup differences at PEEP of 10 cm H2O. During the second IPSM only the PLV group retained its ability to increase PaO2 to the level obtained during the first IPSM (P < .05 compared with control and EP groups). During the first IPSM all three groups showed increasing trend in static compliance (Cst) with PEEP peaking at PEEP of 8 cm H2O. During the second IPSM, only the PLV group showed increase in static compliance with PEEP (P < .05 compared with other groups). Lung histology revealed significantly less hyaline membrane formation in the PLV group (P < .05).

CONCLUSION

PLV shows dose-dependent increase in oxygenation with PEEP and may reduce lung damage associated with mechanical ventilation.

Procyanidins in crataegus extract evoke endothelium-dependent vasorelaxation in rat aorta

The extract of Crataegus, a mixture of flavonoids and procyanidins extracted from hawthorn, Crataegus oxyacantha, L. and C. monogyna Jacq., relaxed vascular tone or increased production of cyclic GMP in the rat aorta, but flavonoid components of Crataegus extract, hyperoside, rutin and vitexin, did not affect the vascular tone. The aim of the present study was to characterize the endothelium-dependent relaxation elicited by procyanidins fractionated from Crataegus extract in isolated rat aorta. Procyanidins caused endothelium-dependent relaxation which was associated with the production of cyclic GMP. Both responses to these procyanidins were inhibited by methylene blue or N(G)-nitro-L-arginine, but not by indomethacin. Relaxation in response to procyanidins was not affected by atropine, diphenhydramine, [D-Pro2,D-Trp7,9]substance P, propranolol, nifedipine, verapamil and glibenclamide, but were markedly reduced by tetraethylammonium. These findings showed that procyanidins in Crataegus extract may be responsible for the endothelium-dependent nitric oxide-mediated relaxation in isolated rat aorta, possibly via activation of tetraethylammonium-sensitive K+ channels.

Role of glucose utilization in the restoration of hypophysectomy-induced hepatic cytochrome P450 2E1 by growth hormone in rats

Growth hormone and insulin are the primary determinants for cytochrome P450 2E1 (CYP2E1) expression. The role of glucose on the induction of CYP2E1 by hypophysectomy and on the restorative effect by growth hormone was investigated in the rat liver. Western and Northern blot analyses revealed that hypophysectomy induced CYP2E1 by 5-fold at 1-4 weeks, relative to control, with a concomitant increase in CYP2E1 mRNA. Hypophysectomized rats (HXR) showed a 20% reduction in the plasma glucose level. Hypophysectomy-induced increase in the CYP2E1 mRNA was completely abolished by glucose feeding in drinking water (10%) for 7 days. Treatment of HXR with hGH (2 I.U./kg, twice a day, for 7 days) inhibited the increases in CYP2E1 protein and mRNA levels with restoration of the plasma glucose level. In contrast to the effect of human growth hormone (hGH) on CYP2E1 in HXR with free access to foods, CYP2E1 expression failed to be restored by hGH in starving HXR. However, glucose feeding of starving HXR abolished the induction of CYP2E1. Effects of hypophysectomy and hGH treatment were studied in streptozotocin-induced diabetic rats. Insulin, but not hGH, prevented an increase in CYP2E1 mRNA in diabetic rats. The hepatic CYP2E1 induction in hypophysectomized diabetic rats was inhibited by hGH treatment, indicating that the hGH effect on CYP2E1 expression did not involve insulin production. These results provide evidence that the induction of hepatic CYP2E1 by hypophysectomy may result from reduced glucose utilization, and that the effect of hGH on CYP2E1 expression may be mediated with enhanced glucose utilization, but not with insulin production.

BCG infection during pre-sensitization or even post-sensitization inhibits airway sensitivity in an animal model of allergic asthma

The objective of this study is to investigate whether BCG infection before, during or after sensitization suppresses allergen-induced airway hyperresponsiveness and eosinophilic inflammation in allergic asthma rats, and to determine the required dose of BCG to induce such an inhibition. Eighty-seven Sprague-Dawley (SD) rats were sensitized and provoked with ovalbumin (OA). A pretreatment of 6 x 10(4) or 6 x 10(5) colony forming units (CFUs) of BCG or saline was done at four different times: 3 days before sensitization, at sensitization, 3 days before provocation, or at provocation. The assessment of tracheal smooth muscle (TSM) responsiveness to electrical field stimulation or acetylcholine (ACh) and bronchoalveolar lavage (BAL) were performed 1 day after OA provocation. Doses of 6 x 10(4) CFUs inhibited TSM sensitivity of rats infected 3 days before sensitization or at sensitization, but not 3 days before provocation or at provocation. However, doses of 6 x 10(5) CFUs significantly inhibited not only the airway eosinophilia of rats infected 3 days before sensitization or at sensitization, but also the TSM sensitivity of rats infected 3 days before provocation or at provocation. In conclusion, BCG infection suppresses the development of sensitivity of airway smooth muscle and airway eosinophilic inflammation in allergic asthma rats. Furthermore, a relatively high dose of BCG infection inhibits airway sensitivity, even after allergen sensitization.

Interferon-gamma- and interleukin-4-targeted gene therapy for atopic allergic disease

Two cytokines, interferon-gamma (IFN-gamma) and interleukin-4 (IL-4), which play critical roles in the regulation of serum IgE level by directing the interplay of T helper (Th)1 and Th2 cells, were chosen as targets for gene therapy. Anti-allergic activity was evaluated by determining the serum IgE level, and the functional status of each helper T cell was monitored by the serum concentrations of IgG1 and IgG2a. Experimental animals (BALB/c mice) were divided into four groups: the control group; the ovalbumin (OVA) group; the IFN-gamma group; and the IL-4 group. The control group was injected with saline and the OVA group with OVA-alum. The IFN-gamma and IL-4 groups were treated with OVA-alum plus the cDNAs of mouse IFN-gamma and IL-4 in an expression vector. These treatments were applied intramuscularly on a monthly basis for 4 months. OVA-alum treatment significantly increased the serum IgE and IgG1 concentrations, but did not affect IgG2a. Concomitant treatments with the cDNA of IFN-gamma or IL-4 returned the serum IgE almost to the control level and significantly suppressed the OVA-induced increase of IgG1. IFN-gamma cDNA increased the serum IgG2a but IL-4 cDNA had no affect. These results suggest that IFN-gamma inhibited the OVA-induced IgE production by suppressing the Th2 pathway and by enhancing the Th1 pathway. Administration of IL-4 cDNA suppressed the OVA-induced enhancement of IgE production by inhibiting the Th2 pathway rather than by potentiating it.