Tatsuro Okamoto

Tumor suppressive microRNA-133a regulates novel molecular networks in lung squamous cell carcinoma

Analysis of the microRNA (miRNA) expression signature of lung squamous cell carcinoma (lung-SCC) revealed that the expression levels of miR-133a were significantly reduced in cancer tissues compared with normal tissues. In this study, we focused on the functional significance of miR-133a in cancer cell lines derived from lung-SCC and the identification of miR-133a-regulated novel cancer networks in lung-SCC. Restoration of miR-133a expression in PC10 and H157 cell lines resulted in significant inhibition of cell proliferation, suggesting that miR-133a functions as a tumor suppressor. We used genome-wide gene expression analysis to identify the molecular targets of miR-133a regulation. Gene expression data and web-based searching revealed several candidate genes, including transgelin 2 (TAGLN2), actin-related protein2/3 complex, subunit 5, 16kDa (ARPC5), LAG1 homolog, ceramide synthase 2 (LASS2) and glutathione S-transferase pi 1 (GSTP1). ARPC5 and GSTP1 likely represent bona fide targets as their expression is elevated in lung-SCC clinical specimens. Furthermore, transient transfection of miR-133a, repressed ARPC5 and GSTP1 mRNA and protein levels. As cell proliferation was significantly inhibited in lung-SCC cells following RNAi knock down of either gene, ARPC5 and GSTP1 may function as oncogenes in the development of lung-SCC. The identification of a tumor suppressive miRNA and the novel cancer pathways it regulates could provide new insights into potential molecular mechanisms of lung-SCC carcinogenesis.

XPG mRNA Expression Levels Modulate Prognosis in Resected Non–Small-Cell Lung Cancer in Conjunction with BRCA1 and ERCC1 Expression

BACKGROUND Molecular markers can help identify patients with early-stage non-small-cell lung cancer (NSCLC) with a high risk of relapse. Excision repair cross-complementing 1 (ERCC1), Xeroderma pigmentosum group G (XPG), and breast cancer 1 (BRCA1) are involved in DNA damage repair, whereas ribonucleotide reductase M1 (RRM1) is implicated in DNA synthesis. Expression levels of these molecules might therefore have a prognostic role in lung cancer. PATIENTS AND METHODS We examined ERCC1, RRM1, XPG, and BRCA1 mRNA levels by real-time quantitative polymerase chain reaction in 54 patients with stage IB-IIB resected NSCLC. A strong correlation was observed between the 4 genes. RESULTS For patients with low BRCA1, regardless of XPG mRNA expression levels, disease-free survival (DFS) was not reached. For patients with intermediate/high BRCA1 and high XPG, DFS was 50.7 months. However, for patients with intermediate/high BRCA1 and low/intermediate XPG, DFS decreased to 16.3 months (P = .002). Similar differences were observed in overall survival, with median survival not reached for patients with low BRCA1, regardless of XPG levels, or for patients with intermediate/high BRCA1 and high XPG. Conversely, for patients with intermediate/high BRCA1 levels and low/intermediate XPG levels, median survival dropped to 25.5 months (P = .007). CONCLUSION BRCA1 and XPG were identified as independent prognostic factors for both median survival and DFS. High BRCA1 mRNA expression confers poor prognosis in early NSCLC, and the combination of high BRCA1 and low XPG expression still further increases the risk of shorter survival. These findings can help optimize the customization of adjuvant chemotherapy.

Expression of TrkB and BDNF is associated with poor prognosis in non-small cell lung cancer

High expression levels of TrkB and BDNF are associated with aggressive malignant behavior in tumor cells and a poor prognosis in patients with various types of cancer. In this study, we aimed to identify the relationship between TrkB and BDNF expression and clinicopathological variables and prognosis in non-small cell lung cancer (NSCLC). We evaluated TrkB and BDNF expression in the tumor cells of 102 NSCLC patients by immunohistochemistry. Out of all clinicopathological factors examined, only vascular invasion was significantly correlated with TrkB (P=0.010) and BDNF (P=0.015) expression. TrkB-positive tumors had significantly worse disease-free survival (P=0.0094) and overall survival (P=0.0019) than TrkB-negative tumors, and TrkB expression was an independent prognostic factor for disease-free survival (HR 3.735, 95% CI 1.560-11.068, P=0.002) and overall survival (HR 4.335, 95% CI 1.534-15.963, P=0.004) in multivariate analysis. Finally, our analysis revealed that co-expression of TrkB and BDNF conferred poorer prognosis compared with overexpression of either protein alone. Our results indicate that expression of TrkB and BDNF is associated with poor prognosis in NSCLC patients.

Clinical Significance of PD-L1 Protein Expression in Surgically Resected Primary Lung Adenocarcinoma.

Introduction The clinicopathological features of carcinomas expressing programmed death ligand 1 (PD‐L1) and their associations with common driver mutations, such as mutations in the EGFR gene, in lung adenocarcinoma are not clearly understood. Here, we examined PD‐L1 protein expression in surgically resected primary lung adenocarcinoma and the association of PD‐L1 protein expression with clinicopathological features, EGFR mutation status, and patient outcomes. Methods The expression of PD‐L1 protein in 417 surgically resected primary lung adenocarcinomas was evaluated by immunohistochemical analysis. The cutoff value for defining PD‐L1 positivity was determined according to the histogram of proportions of PD‐L1–positive cancer cells. Results Samples from 85 patients (20.4%) and 144 patients (34.5%) were positive for PD‐L1 protein expression according to 5% and 1% PD‐L1 cutoff values, respectively. Fisher’s exact tests showed that PD‐L1 positivity was significantly associated with male sex, smoking, higher tumor grade, advanced T status, advanced N status, advanced stage, the presence of pleural and vessel invasions, micropapillary or solid predominant histological subtypes, and wild‐type EGFR. Univariate and multivariate survival analyses revealed that patients with PD‐L1 positivity had poorer prognoses than those without PD‐L1 protein expression at the 1% cutoff value (disease‐free survival p < 0.0001, overall survival p < 0.0001). Conclusions PD‐L1 protein expression was significantly higher in smoking‐associated adenocarcinoma and in EGFR mutation–negative adenocarcinoma. PD‐L1 protein expression was associated with poor survival in patients with lung adenocarcinoma. The PD‐L1/programmed cell death 1 pathway may contribute to the progression of smoking‐associated tumors in lung adenocarcinoma.

PD-L1 Is Upregulated by Simultaneous Amplification of the PD-L1 and JAK2 Genes in Non–Small Cell Lung Cancer

Objectives The programmed death ligand 1(PD‐L1)/programmed cell death protein 1 (PD‐1) pathway is one of the most important checkpoint pathways for mediating tumor‐induced immune suppression through T‐cell exhaustion. Recently, targeted therapies using monoclonal antibodies against components of this pathway have been shown to reduce tumor burden in patients with non–small cell lung cancer (NSCLC). However, the prognostic significance of PD‐L1 expression is controversial and the precise mechanisms of PD‐L1 gene activation in lung cancer have yet to be clarified. Methods We investigated copy number alterations (CNAs) in the PD‐L1 gene by real‐time PCR in 94 surgically resected lung cancer samples to find possible associations between PD‐L1 CNA and lung cancer biology. Janus kinase 2 gene (JAK2) CNA and its influence on the PD‐L1/PD‐1 pathway were also assessed. Results Five samples were shown to have PD‐L1 gene amplification, whereas 89 samples did not. The patients with PD‐L1 amplification had worse prognoses than did those without PD‐L1 amplification. Genetic amplification of the PD‐L1 gene was correlated with JAK2 gene amplification. The lung cancer cell line HCC4006 was found to harbor both JAK2 and PD‐L1 amplification. Flow cytometry analyses revealed the level of PD‐L1 protein expression to be higher in HCC4006 cells than in other NSCLC cell lines. Expression of the PD‐L1 protein was significantly reduced by the JAK2 inhibitor TG‐101348 and the signal transducer and activator of transcription 3 (STAT‐3) inhibitor BP‐1‐102, but not by the STAT1 inhibitor fludarabine. Conclusions Our data suggest that expression of PD‐L1 protein is upregulated by the simultaneous amplification of the PD‐L1 and JAK2 genes through JAK‐STAT signaling in NCSLC.

Induction chemoradiotherapy and surgical resection for selected stage IIIB non–small-cell lung cancer

BACKGROUND Combination chemotherapy using an oral combination of uracil and tegafur (UFT) plus cisplatin and concurrent thoracic radiotherapy is reported to have a high response rate and less toxicity for locally advanced non-small-cell lung cancer (NSCLC) patients. We performed a phase II trial using this chemoradiotherapy as an induction treatment. METHODS Patients with marginally resectable stage IIIB NSCLC, an age younger than 70 years, a performance status of 0 or 1, and good organ function were eligible. The UFT (400 mg/m(2)) was administered orally on days 1 through 14 and 22 through 35 and cisplatin (80 mg/m(2)) was injected intravenously on days 8 and 29. Radiotherapy with a total dose of 40 Gy was delivered in 20 fractions from day 1. A surgical resection was performed from 3 to 6 weeks after completing the induction treatment. RESULTS Twenty-seven patients, 18 male and 9 female with a median age of 56 years and ranging from 36 to 69 years, were entered into the phase II trial. Clinical T4 and N3 cancers were observed in 22 and 7 patients, respectively. Twenty-five (93%) achieved a partial response. The most frequently observed adverse event was grade 3 leukopenia in 26%. Of 25 patients who underwent a thoracotomy, 22 had a tumor resection. In all 22 patients a complex resection including a resection of the superior vena cava, carina, and vertebrae was required. Operative morbidity and mortality rates were 36% and 4% respectively. The calculated 1-year and 3-year survival rates of all 27 patients were 73% and 56% respectively. CONCLUSIONS Chemotherapy using UFT plus cisplatin and concurrent radiotherapy as induction treatment and a surgical resection for patients with marginally resectable stage IIIB NSCLC is feasible and promising. However it is difficult to conduct multi-institutional trials even for selected stage IIIB disease as a complex resection in almost all patients is necessary.

Postoperative radiotherapy is effective for thymic carcinoma but not for thymoma in stage II and III thymic epithelial tumors: the Japanese Association for Research on the Thymus Database Study.

The efficacy of postoperative radiotherapy (PORT) for thymic epithelial tumors is still controversial. Using the Japanese Association for Research on the Thymus (JART) database, this study was aimed at clarifying the efficacy of PORT for Masaoka stage II and III thymic carcinoma and thymoma.

Role of Activating Transcription Factor 3 (ATF3) in Endoplasmic Reticulum (ER) Stress-induced Sensitization of p53-deficient Human Colon Cancer Cells to Tumor Necrosis Factor (TNF)-related Apoptosis-inducing Ligand (TRAIL)-mediated Apoptosis through Up-regulation of Death Receptor 5 (DR5) by Zerumbone and Celecoxib

Background: Death receptor 5 (DR5) triggers cell death upon binding to its ligand TRAIL. Results: ATF3 promotes DR5 induction and apoptotic cell death upon zerumbone or celecoxib treatment in human p53-deficient colorectal cancer cells. Conclusion: ATF3 is an essential transcription factor for p53-independent DR5 induction through the ROS-ER stress pathway. Significance: ATF3 may be a useful biomarker for TRAIL-based anticancer therapy. Death receptor 5 (DR5) is a death domain-containing transmembrane receptor that triggers cell death upon binding to its ligand, TNF-related apoptosis-inducing ligand (TRAIL), and a combination of TRAIL and agents that increase the expression of DR5 is expected to be a novel anticancer therapy. In this report, we demonstrate that the stress response gene ATF3 is required for endoplasmic reticulum stress-mediated DR5 induction upon zerumbone (ZER) and celecoxib (CCB) in human p53-deficient colorectal cancer cells. Both agents activated PERK-eIF2α kinases and induced the expression of activating transcription factor 4 (ATF4)-CCAAT enhancer-binding protein (C/EBP) homologous protein, which were remarkably suppressed by reactive oxygen species scavengers. In the absence of ATF3, the induction of DR5 mRNA and protein was abrogated significantly, and this was associated with reduced cell death by cotreatment of TRAIL with ZER or CCB. By contrast, exogenous expression of ATF3 caused a more rapid and elevated expression of DR5, resulting in enhanced sensitivity to apoptotic cell death by TRAIL/ZER or TRAIL/CCB. A reporter assay demonstrated that at least two ATF/cAMP response element motifs as well as C/EBP homologous protein motif at the proximal region of the human DR5 gene promoter were required for ZER-induced DR5 gene transcription. Taken together, our results provide novel insights into the role of ATF3 as an essential transcription factor for p53-independent DR5 induction upon both ZER and CCB treatment, and this may be a useful biomarker for TRAIL-based anticancer therapy.

Persistent and aggressive treatment for thymic carcinoma : Results of a single-institute experience with 25 patients

Objectives: The aim of this study is to retrospectively evaluate the role of several therapies, mainly chemotherapy, for thymic carcinoma (TC). Methods: From July 1973 to July 2005, 25 patients (15 males and 10 females) with histologically proven TC were treated at our department. The median age of the patients was 59 years, with a range of from 30 to 78 years. According to Masaoka’s staging system, there was 1 stage I patient, 3 stage II, 7 stage III, 6 stage IVa, and 8 stage IVb patients. The histological subtype was in all cases squamous cell carcinoma, nonkeratinizing type. Results: There were 6 complete surgical resections, 1 incomplete resection followed by chemoradiotherapy, 6 with radiotherapy alone, 3 with radiotherapy plus chemotherapy, and 9 with chemotherapy alone as the initial treatment. Eighteen patients were administered second-line therapy. The regimen obtaining the best response rate was doublet chemotherapy consisting of carboplatin (CBDCA) and paclitaxel. The median survival time and survival rate at 5 years for the patients excluding surgical cases with stage I/II disease were 32 months and 31%, respectively. Conclusion: The doublet of CBDCA and paclitaxel thus appears to be a promising regimen for TC and further investigation in a multi-institutional phase II trial is, therefore, strongly called for.

Malignant schwannoma of the upper mediastinum originating from the vagus nerve

BackgroundMalignant schwannoma of the upper mediastinum originating from the vagus nerve is extremely rare.Case presentationA 46-year-old female was admitted for a left cervical mass which was associated with both hoarseness and Horners syndrome. Chest computed tomography showed a mass extending from the left upper mediastinum to the left supraclavicular area. A fine needle aspiration cytological examination suggested primary lung cancer stage IIIB large cell carcinoma. After administering induction chemo-radiotherapy, a complete surgical resection was performed. The tumor was found to involve both the left vagus nerve and the left sympathetic nerve. Histological examination of the resected specimen revealed the tumor to be malignant schwannoma.ConclusionDespite incorrect preoperative diagnosis, the multimodality treatment administered in this case, including induction chemo-radiotherapy and surgery, proved to be effective.