Masataka Onizuka

Necessity of dual blockade of endothelin ETA and ETB receptor subtypes for antagonism of endothelin-1-induced contraction in human bronchi

1 Endothelin (ET)‐1 has been postulated to be involved in the development of obstructive airway diseases in man. In the present study, we attempted to characterize ET receptor subtypes mediating ET‐1‐induced contraction in human isolated bronchi. The ET receptor antagonists used in the present study were BQ‐123 (ETA receptor‐selective), BQ‐788 (ETB receptor‐selective) and BQ‐928 (ETA/ETB dual). Sarafotoxin S6c (S6c) was also used as an ETB receptor‐selective agonist. 2 In human bronchi, ET‐1 and S6c (10−12 m to 10−7 M) produced concentration‐dependent contraction with almost equal potency (pD2: 8.88± 0.16 for ET‐1 and 9.42±0.15 for S6c). The contraction induced by S6c was competitively antagonized by BQ‐788 alone (1 and 10 μm) with a pKB value of 7.49±0.21, suggesting that the stimulation of ETB receptors causes a contraction of human bronchi. However, contrary to expectation, the concentration‐response curves for ET‐1 were not affected by BQ‐788. The ET‐1‐ and S6c‐induced contractions were not affected by BQ‐123 (10 μm). Thus, ET‐1‐induced contraction of human bronchi is not antagonized by BQ‐123 alone or by BQ‐788 alone. 3 Combined treatment with 10 μm BQ‐123 and 10 μm BQ‐788 significantly antagonized the contraction induced by ET‐1 with a dose‐ratio of 11. BQ‐928 also significantly antagonized ET‐1‐induced contraction with a pKB value of 6.32±0.24. 4The specific binding of [125I]‐ET‐1 to human bronchial membrane preparations was inhibited by BQ‐123 (100 pM to 1 μm) by approximately 40%. Combination treatment with BQ‐788 (100 pM to 1 μm) completely inhibited the BQ‐123‐resistant component of [125I]‐ET‐1 specific binding. 5 In conclusion, the present study demonstrates that BQ‐788 alone cannot inhibit ET‐1‐induced contractions in human bronchi, although human bronchial ETB receptors are BQ‐788‐sensitive. Furthermore, it was shown that blockade of both receptor subtypes antagonizes ET‐1‐induced contraction, and that both receptor subtypes co‐exist in human bronchial smooth muscles. These findings suggest that ETA receptors as well as ETB receptors are involved in ET‐1‐induced contraction in human bronchi. If ET‐1 is involved in human airway diseases, dual blockade of ETA and ETB receptors may be necessary to treat the diseases.

Hypermethylation of the TSLC1/IGSF4 promoter is associated with tobacco smoking and a poor prognosis in primary nonsmall cell lung carcinoma

The tumor suppressor gene TSLC1/IGSF4 on chromosomal region 11q23 is frequently inactivated by promoter methylation in various cancers, including nonsmall cell lung carcinoma (NSCLC). Several studies have demonstrated that the hypermethylation of the CpG islands of genes, including tumor suppressors, is associated with exposure to tobacco smoke. The purpose of this study was to investigate the possible association of TSLC1/IGSF4 methylation with tobacco smoking as well as with the clinical characteristics of tumors using a large number of primary NSCLC.

Promoter methylation of DAL-1/4.1B predicts poor prognosis in non-small cell lung cancer.

Purpose: DAL-1/4.1B is an actin-binding protein originally identified as a molecule whose expression is down-regulated in lung adenocarcinoma. We have previously shown that a lung tumor suppressor, TSLC1, associates with DAL-1, suggesting that both proteins act in the same cascade. The purpose of this study is to understand the molecular mechanisms and clinical significance of DAL-1 inactivation in lung cancer. Experimental Design: We studied aberration of the DAL-1 in 103 primary non–small cell lung cancers (NSCLC) and 18 lung cancer cells. Expression and allelic and methylation status of DAL-1 was examined by reverse transcription-PCR, microsatellite analysis, and bisulfite sequencing or bisulfite single-strand conformational polymorphism, respectively. Results: Loss of DAL-1 expression was strongly correlated with promoter methylation in lung cancer cells, whereas DAL-1 expression was restored by a demethylating agent, 5-aza-2′-deoxycytidine. The DAL-1 promoter was methylated in 59 (57%) primary NSCLC tumors, 37% of which were associated with loss of heterozygosity around the DAL-1 on chromosomal region 18p11.3. In squamous cell carcinomas, DAL-1 methylation was observed in 9 of 10 tumors at stage I, whereas the incidence of methylation gradually increased in adenocarcinomas as they progressed [13 of 36 (36%), 4 of 12 (33%), 14 of 17 (82%), and 3 of 3 (100%) tumors at stages I, II, III, and IV, respectively; P = 0.0026]. Furthermore, in adenocarcinomas, disease-free survival and overall survival were significantly shorter in patients with tumors harboring the methylated DAL-1 (P = 0.0011 and P = 0.045, respectively). Conclusions:DAL-1 methylation is involved in the development and progression of NSCLC and provides an indicator for poor prognosis.

Preoperative lymphocyte count is an independent prognostic factor in node-negative non-small cell lung cancer

A number of prognostic factors have been reported in non-small cell lung cancer (NSCLC). Although lymph node metastasis is the most poorly predictive value in completely resected NSCLC, a significant number of patients have a fatal recurrence even in node-negative curative NSCLC. Recently inflammatory response has been shown as a predictive value in NSCLC. Neutrophils and lymphocytes play an important role in cancer immune response. In this study, we retrospectively examined the impact of preoperative peripheral neutrophil and lymphocyte counts on survival, and investigated the relationships of these factors to clinicopathological factors in node-negative NSCLC. A total 237 patients were evaluated. When the cut-off value of neutrophil count was 4500 mm(-3) with a maximum log-rank statistical value, overall 5-year survival rates were 79.7% for the low-neutrophil-count group and 69.5% for the high-neutrophil-count group (P=0.04). When the cut-off value of lymphocyte count was 1900 mm(-3) with a maximum log-rank statistical value, overall survival rates were 67.9% for the low-lymphocyte group and 87.7% for the high-lymphocyte group (P<0.001). High-neutrophil-counts were associated with tumor size (P=0.002) and pleural invasion (P<0.001). Low-lymphocyte-counts were correlated with vascular invasion (P=0.018) and recurrence of NSCLC (P=0.01). Multivariate analysis showed that the lymphocyte count was an independent prognostic factor (hazard ratio: 3.842; 95% confidence interval: 1.827-8.078; P<0.001), but the neutrophil count was not (P=0.185). We conclude that a peripheral lymphocyte count, which is associated with vascular invasion, is an independent prognostic factor in node-negative NCSLC.

Preoperative radiotherapy and surgery for advanced thymoma with invasion to the great vessels

From 1983 to 1994, 12 advanced thymomas with invastion to the great vessels were initially treated by irradiation (mean dose, 18.3 Gy) and subsequent surgical resection. In nine patients, complete resection was possible by concomitant resection of the surrounding tissues, mainly pericardium and/or brachiocephalic vein. Histologically, all tumors showed prominent fibrosis. Ten patients also received postoperative radiotherapy (mean dose, 42.3 Gy). Tumor‐related deaths occurred in only two patients; one who did not receive postoperative irradiation 21 months and one who had viable cells at the surgical margin 10 months after operation. However, there were also 2 patients who died of respiratory failure due to operation and/or irradiation, one 45 days and the other 7 years after the treatment. Preoperative radiotherapy could facilitate complete resection of the advanced thymomas. The prognosis of the patients treated with preoperative radiotherapy seemed fair if followed by adequate resection and subsequent irradiation.

Endoscopic criteria of early squamous cell carcinoma of the bronchus

Background. Early lung cancer, not extending beyond the bronchial cartilaginous layer without regional lymph node involvement is considered curable by endoscopic laser therapy or limited surgery. The endoscopic criteria for early squamous cell carcinoma of the bronchus, however, have not yet been determined.

Carcinomatous meningitis from non-small-cell lung cancer responding to gefitinib.

The prognosis for carcinomatous meningitis remains poor, and focal neurological dysfunctions usually do not improve despite the available treatment options. We report a case of carcinomatous meningitis from non-small-cell lung cancer treated with gefitinib, which brought about a sustained clinical response. A 40-year-old Japanese man was diagnosed with adenocarcinoma in the right lower lobe of the lung, and with multiple pulmonary and brain metastases. Six courses of carboplatin and paclitaxel chemotherapy and gamma-knife radiosurgery induced a near complete response in all lesions. However, 2 months later, cauda equina syndrome and left oculomotor paralysis from carcinomatous meningitis developed rapidly. Magnetic resonance imaging of the brain and spinal cord revealed the enhancement of leptomeningeal disseminations. The patient was treated with 250 mg/day gefitinib. All his neurological symptomatology disappeared within 2 weeks. The shrinkage of the leptomeningeal disseminations was confirmed by follow-up magnetic resonance imaging. The patient is currently doing well and is able to work. Cancer relapse was not observed at 4 months after the initiation of gefitinib. Although the survival benefit is controversial, gefitinib may have a role in the treatment of carcinomatous meningitis from non-small-cell lung cancer to improve neurological dysfunctions.

Pathologic Radioresponse of Preoperatively Irradiated Invasive Thymomas

Background: We have been applying preoperative radiotherapy (RT) to Masaoka stage III thymomas intending to make surgical resection more complete by reducing mass volume, to prevent possible dissemination caused by surgical manipulation and to get better survival as a result. However, the radioresponses vary from tumor to tumor. We hypothesized that thymoma is a variable radioresponsive tumor depending on pretreatment histology. Materials and Methods: Twenty-one of stage III thymomas underwent preoperative RT plus surgery followed by postoperative RT between 1982 and 2004. Reduction ratios, histopathologic changes according to WHO histologic criteria, resectability, long-term survival, and disease control, by preoperative RT were analyzed. Results: Pretreatment WHO subtypes were type AB (n = 1), B1 (5), B2 (6), B3 (4), and unclassified (5). Sixteen tumors (76.2%) decreased in size after preoperative RT with a mean (median) reduction ratio of 30.8% (27.0%). Type B1or B2 group had higher reduction ratio than type B3 group (mean value of 39.7%, 31.8%, and 21.0%, respectively, p < 0.01). Histopathologically, lymphocyte diminished markedly in type B1 thymoma, and both lymphocyte and epithelial cells diminished in type B2, whereas none of the B3 tumors showed any histologic change. The values of all the cases is 90.5% in complete resection, 19.0% in no combined resection of the adjacent organs, and 77.6% and 83.6% in overall and disease-free 10-year survival, respectively, and these value do not differ according to the WHO histologic criteria. Conclusions: This modality at modest doses was macroscopically and histopathologically effective on tumors particularly in WHO B1 and B2 thymomas than WHO B3 thymoma. The therapeutic benefit of preoperative RT followed by surgery and postoperative RT for stage III thymomas should be defined thoroughly.

Plasma concentrations of endothelin-1 and endothelin-3 are altered differently in various pathophysiological conditions in humans

Several studies have indicated that endothelin-1 (ET-1) and endothelin-3 (ET-3) are produced by different cells. Although ET-1 is produced by vascular endothelial cells, these cells do not produce ET-3. In the present study, we measured plasma concentrations of both ET-1 and ET-3 by sandwich-enzyme immunoassays which we developed recently in patients on chronic hemodialysis, age-matched normal subjects, patients with acute myocardial infarction, patients undergoing surgery, and healthy subjects before and after strenuous endurance exercise. Plasma levels of ET-1 and ET-3 were demonstrated to be altered differently in the above conditions in humans. Although the exact origin of circulating endothelins has yet to be elucidated, the different alterations of plasma levels suggest that both ET-1 and ET-3 may play different roles in physiological and/or pathophysiological responses to various conditions in humans.

High-dose concurrent chemo–proton therapy for Stage III NSCLC: preliminary results of a Phase II study

The aim of this report is to present the preliminary results of a Phase II study of high-dose (74 Gy RBE) proton beam therapy (PBT) with concurrent chemotherapy for unresectable locally advanced non-small-cell lung cancer (NSCLC). Patients were treated with PBT and chemotherapy with monthly cisplatin (on Day 1) and vinorelbine (on Days 1 and 8). The treatment doses were 74 Gy RBE for the primary site and 66 Gy RBE for the lymph nodes without elective lymph nodes. Adapted planning was made during the treatment. A total of 15 patients with Stage III NSCLC (IIIA: 4, IIIB: 11) were evaluated in this study. The median follow-up period was 21.7 months. None of the patients experienced Grade 4 or 5 non-hematologic toxicities. Acute pneumonitis was observed in three patients (Grade 1 in one, and Grade 3 in two), but Grade 3 pneumonitis was considered to be non-proton-related. Grade 3 acute esophagitis and dermatitis were observed in one and two patients, respectively. Severe ( ≥ Grade 3) leukocytopenia, neutropenia and thrombocytopenia were observed in 10 patients, seven patients and one patient, respectively. Late radiation Grades 2 and 3 pneumonitis was observed in one patient each. Six patients (40%) experienced local recurrence at the primary site and were treated with 74 Gy RBE. Disease progression was observed in 11 patients. The mean survival time was 26.7 months. We concluded that high-dose PBT with concurrent chemotherapy is safe to use in the treatment of unresectable Stage III NSCLC.