Nobuyuki Hizawa

Nrf2 Enhances Cell Proliferation and Resistance to Anticancer Drugs in Human Lung Cancer

Purpose: NF-E2-related factor 2 (Nrf2), a key transcription regulator for antioxidant and detoxification enzymes, is abundantly expressed in cancer cells. In this study, therefore, the role of Nrf2 in cancer cell proliferation and resistance to anticancer drugs was investigated. Experimental Design: We used three human lung cancer cell lines with different degrees of Nrf2 activation: Nrf2 was highly activated in A549 cells, slightly activated in NCI-H292 cells, and not activated in LC-AI cells under unstimulated conditions. Result: A549 cells showed higher resistance to cisplatin compared with NCI-H292 and LC-AI cells. The resistance to cisplatin was significantly inhibited in A549 but not in NCI-H292 or LC-AI cells by knockdown of Nrf2 with its specific small interfering RNA (Nrf2-siRNA). The cell proliferation was also most prominently inhibited in A549 cells by treatment with Nrf2-siRNA. In A549 cells, the expression of self-defense genes, such as antioxidant enzymes, phase II detoxifying enzymes, and drug efflux pumps, was significantly reduced by Nrf2-siRNA concomitant with a reduction of the cellular glutathione level. The degree of DNA crosslink and apoptosis after treatment with cisplatin was significantly elevated in A549 cells by Nrf2-siRNA. Knockdown of Nrf2 arrested the cell cycle at G1 phase with a reduction of the phosphorylated form of retinoblastoma protein in A549 and NCI-H292 cells but not in LC-AI cells. Conclusion: These results indicate that the Nrf2 system is essential for both cancer cell proliferation and resistance to anticancer drugs. Thus, Nrf2 might be a potential target to enhance the effect of anticancer drugs.

Genome-wide association study identifies three new susceptibility loci for adult asthma in the Japanese population

Bronchial asthma is a common inflammatory disease caused by the interaction of genetic and environmental factors. Through a genome-wide association study and a replication study consisting of a total of 7,171 individuals with adult asthma (cases) and 27,912 controls in the Japanese population, we identified five loci associated with susceptibility to adult asthma. In addition to the major histocompatibility complex and TSLP-WDR36 loci previously reported, we identified three additional loci: a USP38-GAB1 locus on chromosome 4q31 (combined P = 1.87 × 10−12), a locus on chromosome 10p14 (P = 1.79 × 10−15) and a gene-rich region on chromosome 12q13 (P = 2.33 × 10−13). We observed the most significant association with adult asthma at rs404860 in the major histocompatiblity complex region (P = 4.07 × 10−23), which is close to rs2070600, a SNP previously reported for association with FEV1/FVC in genome-wide association studies for lung function. Our findings offer a better understanding of the genetic contribution to asthma susceptibility.

Characteristics of a Large Cohort of Patients with Autoimmune Pulmonary Alveolar Proteinosis in Japan

RATIONALE Acquired pulmonary alveolar proteinosis (PAP) is a syndrome characterized by pulmonary surfactant accumulation occurring in association with granulocyte/macrophage colony-stimulating factor autoantibodies (autoimmune PAP) or as a consequence of another disease (secondary PAP). Because PAP is rare, prior reports were based on limited patient numbers or a synthesis of historical data. OBJECTIVES To describe the epidemiologic, clinical, physiologic, and laboratory features of autoimmune PAP in a large, contemporaneous cohort of patients with PAP. METHODS Over 6 years, 248 patients with PAP were enrolled in a Japanese national registry, including 223 with autoimmune PAP. MEASUREMENTS AND MAIN RESULTS Autoimmune PAP represented 89.9% of cases and had a minimum incidence and prevalence of 0.49 and 6.2 per million, respectively. The male to female ratio was 2.1:1, and the median age at diagnosis was 51 years. A history of smoking occurred in 56%, and dust exposure occurred in 23%; instances of familial onset did not occur. Dyspnea was the most common presenting symptom, occurring in 54.3%. Importantly, 31.8% of patients were asymptomatic and were identified by health screening. Intercurrent illnesses, including infections, were infrequent. A disease severity score reflecting the presence of symptoms and degree of hypoxemia correlated well with carbon monoxide diffusing capacity and serum biomarkers, less well with pulmonary function, and not with granulocyte/macrophage colony-stimulating factor autoantibody levels or duration of disease. CONCLUSIONS Autoimmune PAP had an incidence and prevalence higher than previously reported and was not strongly linked to smoking, occupational exposure, or other illnesses. The disease severity score and biomarkers provide novel and potentially useful outcome measures in PAP.

Characterisation of phenotypes based on severity of emphysema in chronic obstructive pulmonary disease

Background: Airflow limitation in chronic obstructive pulmonary disease (COPD) is caused by a mixture of small airway disease and emphysema, the relative contributions of which may vary among patients. Phenotypes of COPD classified purely based on severity of emphysema are not well defined and may be different from the classic phenotypes of “pink puffers” and “blue bloaters”. Methods: To characterise clinical phenotypes based on severity of emphysema, 274 subjects with COPD were recruited, excluding those with physician-diagnosed bronchial asthma. For all subjects a detailed interview of disease history and symptoms, quality of life (QOL) measurement, blood sampling, pulmonary function tests before and after inhalation of salbutamol (0.4 mg) and high-resolution CT scanning were performed. Results: Severity of emphysema visually evaluated varied widely even among subjects with the same stage of disease. No significant differences were noted among three groups of subjects classified by severity of emphysema in age, smoking history, chronic bronchitis symptoms, blood eosinophil count, serum IgE level or bronchodilator response. However, subjects with severe emphysema had significantly lower body mass index (BMI) and poorer QOL scores, evaluated using St George’s Respiratory Questionnaire (SGRQ), than those with no/mild emphysema (mean (SD) BMI 21.2 (0.5) vs 23.5 (0.3) kg/m2, respectively; SGRQ total score 40 (3) vs 28 (2), respectively; p<0.001 for both). These characteristics held true even if subjects with the same degree of airflow limitation were chosen. Conclusions: The severity of emphysema varies widely even in patients with the same stage of COPD, and chronic bronchitis symptoms are equally distributed irrespective of emphysema severity. Patients with the phenotype in which emphysema predominates have lower BMI and poorer health-related QOL.

Genome-wide association study identifies eight new susceptibility loci for atopic dermatitis in the Japanese population.

Atopic dermatitis is a common inflammatory skin disease caused by interaction of genetic and environmental factors. On the basis of data from a genome-wide association study (GWAS) and a validation study comprising a total of 3,328 subjects with atopic dermatitis and 14,992 controls in the Japanese population, we report here 8 new susceptibility loci: IL1RL1-IL18R1-IL18RAP (Pcombined = 8.36 × 10−18), the major histocompatibility complex (MHC) region (P = 8.38 × 10−20), OR10A3-NLRP10 (P = 1.54 × 10−22), GLB1 (P = 2.77 × 10−16), CCDC80 (P = 1.56 × 10−19), CARD11 (P = 7.83 × 10−9), ZNF365 (P = 5.85 × 10−20) and CYP24A1-PFDN4 (P = 1.65 × 10−8). We also replicated the associations of the FLG, C11orf30, TMEM232-SLC25A46, TNFRSF6B-ZGPAT, OVOL1, ACTL9 and KIF3A-IL13 loci that were previously reported in GWAS of European and Chinese individuals and a meta-analysis of GWAS for atopic dermatitis. These findings advance the understanding of the genetic basis of atopic dermatitis.

Thymic Stromal Lymphopoietin Gene Promoter Polymorphisms Are Associated with Susceptibility to Bronchial Asthma

Thymic stromal lymphopoietin (TSLP) triggers dendritic cell--mediated T helper (Th) 2 inflammatory responses. A single-nucleotide polymorphism (SNP), rs3806933, in the promoter region of the TSLP gene creates a binding site for the transcription factor activating protein (AP)-1. The variant enhances AP-1 binding to the regulatory element, and increases the promoter--reporter activity of TSLP in response to polyinosinic-polycytidylic acid (poly[I:C]) stimulation in normal human bronchial epithelium (NHBE). We investigated whether polymorphisms including the SNP rs3806933 could affect the susceptibility to and clinical phenotypes of bronchial asthma. We selected three representative (i.e., Tag) SNPs and conducted association studies of the TSLP gene, using two independent populations (639 patients with childhood atopic asthma and 838 control subjects, and 641 patients with adult asthma and 376 control subjects, respectively). We further examined the effects of corticosteroids and a long-acting β(2)-agonist (salmeterol) on the expression levels of the TSLP gene in response to poly(I:C) in NHBE. We found that the promoter polymorphisms rs3806933 and rs2289276 were significantly associated with disease susceptibility in both childhood atopic and adult asthma. The functional SNP rs3806933 was associated with asthma (meta-analysis, P = 0.000056; odds ratio, 1.29; 95% confidence interval, 1.14-1.47). A genotype of rs2289278 was correlated with pulmonary function. Moreover, the induction of TSLP mRNA and protein expression induced by poly(I:C) in NHBE was synergistically impaired by a corticosteroid and salmeterol. TSLP variants are significantly associated with bronchial asthma and pulmonary function. Thus, TSLP may serve as a therapeutic target molecule for combination therapy.

Inhaled granulocyte/macrophage-colony stimulating factor as therapy for pulmonary alveolar proteinosis.

RATIONALE Inhaled granulocyte/macrophage-colony stimulating factor (GM-CSF) is a promising therapy for pulmonary alveolar proteinosis (PAP) but has not been adequately studied. OBJECTIVES To evaluate safety and efficacy of inhaled GM-CSF in patients with unremitting or progressive PAP. METHODS We conducted a national, multicenter, self-controlled, phase II trial at nine pulmonary centers throughout Japan. Patients who had lung biopsy or cytology findings diagnostic of PAP, an elevated serum GM-CSF antibody level, and a Pa(O(2)) of less than 75 mm Hg entered a 12-week observation period. Those who improved (i.e., alveolar-arterial oxygen difference [A-aDO(2)] decreased by 10 mm Hg) during observation were excluded. The rest entered sequential periods of high-dose therapy (250 microg Days 1-8, none Days 9-14; x six cycles; 12 wk); low-dose therapy (125 microg Days 1-4, none Days 5-14; x six cycles; 12 wk), and follow-up (52 wk). MEASUREMENTS AND MAIN RESULTS Fifty patients with PAP were enrolled in the study. During observation, nine improved and two withdrew; all of these were excluded. Of 35 patients completing the high- and low-dose therapy, 24 improved, resulting in an overall response rate of 62% (24/39; intention-to-treat analysis) and reduction in A-aDO(2) of 12.3 mm Hg (95% confidence interval, 8.4-16.2; n = 35, P < 0.001). No serious adverse events occurred, and serum GM-CSF autoantibody levels were unchanged. A treatment-emergent correlation occurred between A-aDO(2) and diffusing capacity of the lung, and high-resolution CT revealed improvement of ground-glass opacity. Twenty-nine of 35 patients remained stable without further therapy for 1 year. CONCLUSIONS Inhaled GM-CSF therapy is safe, effective, and provides a sustained therapeutic effect in autoimmune PAP. Clinical trial registered with www.controlled-trials.com/isrctn (ISRCTN18931678), www.jmacct.med.or.jp/english (JMA-IIA00013).

Genome-wide association study identifies HLA-DP as a susceptibility gene for pediatric asthma in Asian populations.

Asthma is a complex phenotype influenced by genetic and environmental factors. We conducted a genome-wide association study (GWAS) with 938 Japanese pediatric asthma patients and 2,376 controls. Single-nucleotide polymorphisms (SNPs) showing strong associations (P<1×10−8) in GWAS were further genotyped in an independent Japanese samples (818 cases and 1,032 controls) and in Korean samples (835 cases and 421 controls). SNP rs987870, located between HLA-DPA1 and HLA-DPB1, was consistently associated with pediatric asthma in 3 independent populations (P combined = 2.3×10−10, odds ratio [OR] = 1.40). HLA-DP allele analysis showed that DPA1*0201 and DPB1*0901, which were in strong linkage disequilibrium, were strongly associated with pediatric asthma (DPA1*0201: P = 5.5×10−10, OR = 1.52, and DPB1*0901: P = 2.0×10−7, OR = 1.49). Our findings show that genetic variants in the HLA-DP locus are associated with the risk of pediatric asthma in Asian populations.

Genetic regulation of Dermatophagoides pteronyssinus–specific IgE responsiveness: A genome-wide multipoint linkage analysis in families recruited through 2 asthmatic sibs

BACKGROUND Dermatophagoides pteronyssinus (Der p) is one of the most frequently implicated allergens in atopic diseases. Although HLA could play an important role in the development of the IgE response to the Der p allergens, genetic regulation by non-HLA genes influences certain HLA-associated IgE responses to complex allergens. OBJECTIVE To clarify genetic control for the expression of Der p-specific IgE responsiveness, we conducted a genome-wide search for genes influencing Der p-specific IgE antibody levels by using 45 Caucasian and 53 African American families ascertained as part of the Collaborative Study on the Genetics of Asthma (CSGA). METHODS Specific IgE antibody levels to the Der p crude allergen and to the purified allergens Der p 1 and Der p 2 were measured. Multipoint, nonparametric linkage analysis of 370 polymorphic markers was performed with the GENEHUNTER program. RESULTS The best evidence of genes controlling specific IgE response to Der p was obtained in 2 novel regions: chromosomes 2q21-q23 (P = .0033 for Caucasian subjects) and 8p23-p21 (P = .0011 for African American subjects). Three regions previously proposed as candidate regions for atopy, total IgE, or asthma also showed evidence for linkage to Der p-specific IgE responsiveness: 6p21 (P = .0064) and 13q32-q34 (P = 0.0064) in Caucasian subjects and 5q23-q33 (P = 0.0071) in African American subjects. CONCLUSIONS No single locus generated overwhelming evidence for linkage in terms of established criteria and guidelines for a genome-wide screening, which supports previous assertions of a heterogeneous etiology for Der p-specific IgE responsiveness. Two novel regions, 2q21-q23 and 8p23-p21, that were identified in this study merit additional study.

Molecular mechanisms for the regulation of Nrf2-mediated cell proliferation in non-small-cell lung cancers

We previously demonstrated that the transcription factor NF-E2-related factor2 (Nrf2), expressed abundantly in non-small-cell lung cancer (NSCLC) cells, plays a pivotal role in the proliferation and chemoresistance of NSCLC. Here we show that Nrf2-mediated NSCLC cell proliferation is dually regulated by epidermal growth factor receptor (EGFR) signaling and an Nrf2 repressor protein Keap1 (Kelch-like ECH-associated protein-1). NSCLC cells expressing wild-type EGFR and Keap1 genes show enhanced proliferation on stimulation with EGFR ligand under non-stress conditions. Exposure to cigarette smoke extract (CSE) enhanced cell proliferation by modification of the Nrf2/Keap1 interaction. Although EGFR-tyrosine kinase inhibitor (TKI) inhibited the proliferation of these cells, exposure to CSE attenuated its efficacy. In NSCLC cells with Keap1 gene mutations, Nrf2 was constitutively activated owing to dysfunction of Keap1 and cells proliferated independently of EGFR signaling. Furthermore, EGFR-TKI was unable to inhibit their proliferation. In NSCLC cells with EGFR gene mutations, Nrf2 was constitutively activated by EGFR signaling. In these cells, proliferation was largely dependent on the EGFR signaling pathway. Although these cells were highly sensitive to EGFR-TKI, exposure to CSE or knockdown of Keap1 mRNA reduced sensitivity to EGFR-TKI. We found a case of NSCLC showing resistance to EGFR-TKI despite having EGFR-TKI-sensitive EGFR gene mutation because of dysfunctional mutation in Keap1 gene. Results indicate that oxidative stress reduces the anticancer effects of EGFR-TKI in wild-type Keap1 NSCLC cells. Analysis of Keap1 dysfunction may become a novel molecular marker to predict resistance to EGFR-TKI in NSCLC cells having EGFR-TKI-sensitive EGFR mutations. Finally, as the downstream molecule of both EGFR and Keap1 signaling, Nrf2 is an important molecular target for the treatment of NSCLC, where cells have mutations in EGFR, KRAS or Keap1 genes.