Toshiaki Morikawa

CD8+ tumor-infiltrating lymphocytes together with CD4+ tumor-infiltrating lymphocytes and dendritic cells improve the prognosis of patients with pancreatic adenocarcinoma.

Objective Recent studies have demonstrated the importance of tumor immunity for a cancer patients prognosis. In some types of cancer, it has been shown through immunohistochemical analysis that the existence of CD8+ tumor-infiltrating lymphocytes (TILs) is a crucial factor in determining prognosis. In an experimental model, CD4+ lymphocytes together with CD8+ lymphocytes contributed significantly to tumor immunity. Methods Specimens were taken from 80 surgically resected pancreatic adenocarcinomas between 1992 and 1999. Immunohistochemical staining of CD4, CD8, and S100 protein was performed, and the levels of these proteins were determined by microscopic analysis. The percentages of patients in the CD4(+) and CD8(+) groups were 59% (47/80) and 25% (16/80), respectively. When separated into 4 groups, CD4/8(+/+), CD4/8(+/−), CD4/8(−/+) and CD4/8(−/−), the overall survival rate was significantly higher in CD4/8(+/+) patients (13 cases) compared with those in all other groups combined (67 cases; P = 0.0098). CD4/8(+/+) status was negatively correlated with tumor depth and TNM stage. Multivariate analyses showed that CD4/8(+/+) status was an independent favorable prognostic factor. The number of tumor-infiltrating S100 protein positive cells was also significantly higher in the CD4/8(+/+) group than in others (P = 0.0084). Conclusions In pancreatic adenocarcinoma, the presence of CD4+ TILs together with CD8+ TILs serves as a good indicator of the patients outcome after surgical treatment.

Forty Consecutive Resections of Hilar Cholangiocarcinoma With No Postoperative Mortality and No Positive Ductal Margins: Results of a Prospective Study

Objective:Our objective was to perform a prospective study of surgical treatment of hilar cholangiocarcinoma according to newly established guidelines for performing safe and curative resections. Summary Background Data:The poor survival rate after resection of hilar cholangiocarcinoma is considered to be mainly the result of in-hospital death and positive ductal margins. Methods:Between July 1999 and December 2002, 40 of 42 surgically explored patients with hilar cholangiocarcinoma underwent resection. They were managed with preoperative biliary decompression, portal embolization, cholangiographic evaluation, and a choice of surgical procedures and techniques. Results:Hospital or 30-day mortality and morbidity rates were 0% and 48%, respectively. Hepatic failure was not encountered. Histopathologic examination revealed no positive ductal margins in all 40 patients, but 2 showed positive separation margins from the right hepatic artery. The overall 3-year survival rate and median survival time were 40% and 27 months. Survival of patients with Bismuth type III or IV tumors or of patients who underwent right hepatectomy was significantly better. Survival of patients who underwent concomitant vascular resection was similar to survival of those who did not. Univariate analysis indicated the type of hepatectomy, histopathologic grade, Bismuth classification, concomitant hepatic artery resection, and International Union Against Cancer stage as significant prognostic factors. Conclusions:No postoperative mortality and no positive ductal margins were achieved according to the above guidelines in a high-volume expert center. Long-term results, however, have not been significantly improved. A survival analysis of the patient series with homogeneous conditions derived from a short study period suggests the need for additional strategies including right hepatectomy for Bismuth type I or II tumors.

Long-term benefits for the quality of life after video-assisted thoracoscopic lobectomy in patients with lung cancer.

Quality of life (QOL) after video-assisted thoracic surgical (VATS) lobectomy remains to be defined. Forty-four consecutive patients with clinical stage I lung cancer underwent lobectomy by the VATS approach (n = 22 patients) or thoracotomy approach (n = 22 patients). Acute pain was quantitated by postoperative narcotic requirements and the need for epidural anesthesia. Long-term QOL was assessed by questioning patients about the presence of chronic chest pain, ongoing limitations in arm or shoulder function, time until return to preoperative activity, and satisfaction with the operation. Patients who underwent VATS lobectomy had significant decreases in both acute and chronic chest pain and time until return to preoperative activity. Patients also had more confidence regarding wound size and their overall impression of the operation. In this series, VATS lobectomy was associated with long-term benefits for the QOL in patients with lung cancer. However, the exact role of this approach should be defined by carefully-designed controlled trials studying long-term survival.

Accelerated epithelial cell senescence in IPF and the inhibitory role of SIRT6 in TGF-β-induced senescence of human bronchial epithelial cells

Reepithelialization of remodeled air spaces with bronchial epithelial cells is a prominent pathological finding in idiopathic pulmonary fibrosis (IPF) and is implicated in IPF pathogenesis. Recent studies suggest that epithelial senescence is a risk factor for development of IPF, indicating such reepithelialization may be influenced by the acceleration of cellular senescence. Among the sirtuin (SIRT) family, SIRT6, a class III histone deacetylase, has been demonstrated to antagonize senescence. We evaluated the senescence of bronchiolization in association with SIRT6 expression in IPF lung. Senescence-associated β-galactosidase staining and immunohistochemical detection of p21 were performed to evaluate cellular senescence. As a model for transforming growth factor (TGF)-β-induced senescence of abnormal reepithelialization, we used primary human bronchial epithelial cells (HBEC). The changes of SIRT6, p21, and interleukin (IL)-1β expression levels in HBEC, as well as type I collagen expression levels in fibroblasts, were evaluated. In IPF lung samples, an increase in markers of senescence and SIRT6 expression was found in the bronchial epithelial cells lining cystically remodeled air spaces. We found that TGF-β induced senescence in primary HBEC by increasing p21 expression, and, whereas TGF-β also induced SIRT6, it was not sufficient to inhibit cellular senescence. However, overexpression of SIRT6 efficiently inhibited TGF-β-induced senescence via proteasomal degradation of p21. TGF-β-induced senescent HBEC secreted increased amounts of IL-1β, which was sufficient to induce myofibroblast differentiation in fibroblasts. These findings suggest that accelerated epithelial senescence plays a role in IPF pathogenesis through perpetuating abnormal epithelial-mesenchymal interactions, which can be antagonized by SIRT6.

Insufficient autophagy in idiopathic pulmonary fibrosis

Autophagy, a process that helps maintain homeostatic balance between the synthesis, degradation, and recycling of organelles and proteins to meet metabolic demands, plays an important regulatory role in cellular senescence and differentiation. Here we examine the regulatory role of autophagy in idiopathic pulmonary fibrosis (IPF) pathogenesis. We test the hypothesis that epithelial cell senescence and myofibroblast differentiation are consequences of insufficient autophagy. Using biochemical evaluation of in vitro models, we find that autophagy inhibition is sufficient to induce acceleration of epithelial cell senescence and myofibroblast differentiation in lung fibroblasts. Immunohistochemical evaluation of human IPF biospecimens reveals that epithelial cells show increased cellular senescence, and both overlaying epithelial cells and fibroblasts in fibroblastic foci (FF) express both ubiquitinated proteins and p62. These findings suggest that insufficient autophagy is an underlying mechanism of both accelerated cellular senescence and myofibroblast differentiation in a cell-type-specific manner and is a promising clue for understanding the pathogenesis of IPF.

Mediastinal Lymph Node Staging by FDG-PET in Patients with Non-Small Cell Lung Cancer: Analysis of False-Positive FDG-PET Findings

Background: Accurate staging of mediastinal and hilar lymph nodes is a critical factor determining operability in patients with non-small cell lung cancer (NSCLC). Positron emission tomography with 2-[18F] fluoro-2-deoxy-D-glucose as a tracer (FDG-PET) has recently been reported to be more effective in detecting tumor involvement in mediastinal and hilar lymph nodes than computed tomography (CT). Objective: In this study, we analyzed the accuracy of FDG-PET in mediastinal and hilar lymph node staging in patients with NSCLC and the factors associated with false-positive or false-negative FDG-PET findings in mediastinal and hilar lymph node staging. Methods: Fifty-four patients with NSCLC who underwent preoperative analysis including chest CT and whole-body FDG-PET were evaluated retrospectively. Using FDG-PET, lesions were considered to be positive if a definite, localized area of higher uptake, excluding physiologic uptake, than in surrounding normal tissue was present. On CT findings, lymph nodes were considered to be positive if they were >10 mm in short-axis diameter, except subcarinal lymph nodes (#7), which were considered to be positive if they were >15 mm in short-axis diameter. All patients underwent surgical resection of primary tumors and mediastinal and hilar lymph nodes between 1999 and 2001 in our institute. Resected lymph nodes were histologically examined for the existence of tumor cells. Results: A total of 306 lymph nodes were resected and used for analysis. The sensitivity, specificity, positive predictive value and negative predictive value of FDG-PET were 73, 98, 70 and 98%, while those of CT were 55, 96, 55 and 96%, respectively. When pre-operative nodal staging was compared with post-operative histopathological staging, 44 patients (81%) were correctly staged, 7 (13%) were overstaged and 3 (6%) were understaged by FDG-PET, while 39 patients (72%) were correctly staged, 8 (15%) were overstaged and 7 (13%) were understaged by CT. All 7 overstaged patients by FDG-PET had other pulmonary complications, including interstitial pneumonitis (n = 2), previous pulmonary tuberculosis (n = 3), silicosis (n = 1) and emphysema (n = 1), although they were not in the active stage. In 3 understaged patients by FDG-PET, lymph nodes were also undetectable by CT. Conclusion: FDG-PET is superior to CT in mediastinal and hilar lymph node staging of patients with NSCLC. However, care should be taken in lymph node staging for patients who have other pulmonary complications, including interstitial pneumonitis, previous pulmonary tuberculosis and silicosis.

Insufficient autophagy promotes bronchial epithelial cell senescence in chronic obstructive pulmonary disease

Tobacco smoke-induced accelerated cell senescence has been implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD). Cell senescence is accompanied by the accumulation of damaged cellular components suggesting that in COPD, inhibition of autophagy may contribute to cell senescence. Here we look at whether autophagy contributes to cigarette smoke extract (CSE) - induced cell senescence of primary human bronchial epithelial cells (HBEC), and further evaluate p62 and ubiquitinated protein levels in lung homogenates from COPD patients. We demonstrate that CSE transiently induces activation of autophagy in HBEC, followed by accelerated cell senescence and concomitant accumulation of p62 and ubiquitinated proteins. Autophagy inhibition further enhanced accumulations of p62 and ubiquitinated proteins, resulting in increased senescence and senescence-associated secretory phenotype (SASP) with interleukin (IL)-8 secretion. Conversely, autophagy activation by Torin1, a mammalian target of rapamycin (mTOR inhibitor), suppressed accumulations of p62 and ubiquitinated proteins and inhibits cell senescence. Despite increased baseline activity, autophagy induction in response to CSE was significantly decreased in HBEC from COPD patients. Increased accumulations of p62 and ubiquitinated proteins were detected in lung homogenates from COPD patients. Insufficient autophagic clearance of damaged proteins, including ubiquitinated proteins, is involved in accelerated cell senescence in COPD, suggesting a novel protective role for autophagy in the tobacco smoke-induced senescence-associated lung disease, COPD.

Lung tumors evaluated with FDG-PET and dynamic CT: the relationship between vascular density and glucose metabolism.

Purpose The aim of the current study was to evaluate the relationship between FDG-PET and dynamic CT in lung tumors. Method Forty consecutive patients with pulmonary tumors underwent whole-body FDG-PET and contrast-enhanced dynamic CT. The size of tumors was 2.6 ± 0.2 cm (mean ± SD) at the largest diameter. The standardized uptake value (SUV) of FDG-PET, peak attenuation (APA), and relative flow (RF) of dynamic CT were evaluated. All patients underwent surgery, and tissue samples were available to be studied. The intratumoral microvessel densities (MVDs) were counted and compared with the radiologic parameters. The duration between radiologic examinations and surgery was within 2 weeks in all patients. Results The mean SUV, APA, and RF of lung cancers were significantly higher than those of benign lesions (p < 0.05). The mean APA and RF of lung cancers correlated with mean SUV (APA: r = 0.665, p < 0.0001; RF:r = 0.848, p < 0.05) and mean MVD (APA:r = 0.801, p < 0.0001; RF:r = 0.723, p < 0.05). The mean SUV of lung cancers correlated with the mean MVD (r = 0.612, p < 0.001). No correlation was found between the mean APA, RF, SUV, and MVD in benign tumors. Conclusion The APA and RF of dynamic CT correlated with the SUV of FDG-PET imaging in lung cancer. The APA and RF of dynamic CT as an index of blood pooling may be related to increased glucose metabolism in lung cancer.

Tumor angiogenesis and dynamic CT in lung adenocarcinoma: radiologic-pathologic correlation.

Purpose The purpose of this work was to evaluate the correlation of tumor angiogenesis and dynamic CT in lung adenocarcinoma. Method Thirty-five consecutive patients with lung adenocarcinoma underwent dynamic chest CT. Maximum attenuation of dynamic CT was compared with microvessel densities (MVDs) and vascular endothelial growth factor (VEGF) expression by immunohistochemistry. Results The mean peak attenuation (APA) of lung adenocarcinoma correlated with MVD (r = 0.689, p < 0.0001). VEGF positiveness of lung adenocarcinoma was 63%. There was a significant difference in APA between VEGF-positive and -negative lung adenocarcinomas (39.9 ± 3.9 and 24.3 ± 2.3; p < 0.05). The mean MVDs of VEGF-positive adenocarcinomas were significantly higher than those of negative ones (82.5 ± 5.9 and 49.2 ± 7.1; p < 0.05). The mean APA of VEGF-positive lung adenocarcinomas correlated positively with MVD (r = 0.707, p < 0.0001). Conclusion The APA value of dynamic CT reflects MVD in lung adenocarcinoma. The APA value of dynamic CT might be an index for VEGF-related tumor angiogenesis.

Autophagy induction by SIRT6 through attenuation of insulin-like growth factor signaling is involved in the regulation of human bronchial epithelial cell senescence.

Cigarette smoke (CS)–induced cellular senescence has been implicated in the pathogenesis of chronic obstructive pulmonary disease, and SIRT6, a histone deacetylase, antagonizes this senescence, presumably through the attenuation of insulin-like growth factor (IGF)-Akt signaling. Autophagy controls cellular senescence by eliminating damaged cellular components and is negatively regulated by IGF-Akt signaling through the mammalian target of rapamycin (mTOR). SIRT1, a representative sirtuin family, has been demonstrated to activate autophagy, but a role for SIRT6 in autophagy activation has not been shown. Therefore, we sought to investigate the regulatory role for SIRT6 in autophagy activation during CS-induced cellular senescence. SIRT6 expression levels were modulated by cDNA and small interfering RNA transfection in human bronchial epithelial cells (HBECs). Senescence-associated β-galactosidase staining and Western blotting of p21 were performed to evaluate senescence. We demonstrated that SIRT6 expression levels were decreased in lung homogenates from chronic obstructive pulmonary disease patients, and SIRT6 expression levels correlated significantly with the percentage of forced expiratory volume in 1 s/forced vital capacity. CS extract (CSE) suppressed SIRT6 expression in HBECs. CSE-induced HBEC senescence was inhibited by SIRT6 overexpression, whereas SIRT6 knockdown and mutant SIRT6 (H133Y) without histone deacetylase activity enhanced HBEC senescence. SIRT6 overexpression induced autophagy via attenuation of IGF-Akt-mTOR signaling. Conversely, SIRT6 knockdown and overexpression of a mutant SIRT6 (H133Y) inhibited autophagy. Autophagy inhibition by knockdown of ATG5 and LC3B attenuated the antisenescent effect of SIRT6 overexpression. These results suggest that SIRT6 is involved in CSE-induced HBEC senescence via autophagy regulation, which can be attributed to attenuation of IGF-Akt-mTOR signaling.