Tomoyuki Nakagiri

Epithelial to Mesenchymal Transition Is a Determinant of Sensitivity to Chemoradiotherapy in Non-Small Cell Lung Cancer

BACKGROUND The epithelial to mesenchymal transition (EMT) is a fundamental biological process during which epithelial cells change to a mesenchymal phenotype; it has a profound impact on cancer progression. The purpose of this study was to clarify the role of EMT in the sensitivity of non-small cell lung cancer (NSCLC) to chemoradiotherapy (CRT). METHODS We evaluated the correlation between EMT and sensitivity to chemotherapy or radiotherapy using NSCLC cells induced to undergo EMT with epidermal growth factor or transforming growth factor-β1. Immunohistochemistry was used to examine the expression of EMT markers, E-cadherin, cytokeratin, N-cadherin, and vimentin in 50 tumor specimens obtained from patients with NSCLC both before and after CRT. RESULTS The EMT resulted in increased malignant potential and reduced sensitivity to cisplatin and paclitaxel in NSCLC cells. Furthermore, chronic exposure to cisplatin, paclitaxel, or radiation altered the cells into therapy-resistant sub-lines that showed phenotypic changes such as a spindle-cell shape and increased EMT marker expression. Also, decreased expression of epithelial markers and upregulation of mesenchymal markers were detected in surgically resected specimens after CRT compared with biopsy specimens obtained before treatment. The disease-free survival rate of patients with EMT marker-positive tumors was significantly lower than that of those with EMT marker-negative tumors. CONCLUSIONS The EMT marker expression was detected in NSCLC tumors after CRT, indicating that EMT changes are associated with insensitivity to CRT. New therapeutic combinations using EMT-signaling inhibitors may be needed to circumvent the resistance of some types of cancer to CRT.

Complete versus assisted thoracoscopic approach: a prospective randomized trial comparing a variety of video-assisted thoracoscopic lobectomy techniques

BackgroundVideo-assisted thoracoscopic surgery (VATS) lobectomy does not represent a unified approach, but rather a spectrum of operative techniques ranging from a complete endoscopic thoracotomy to a minithoracotomy. A prospective randomized trial was conducted to compare the differences in these techniques and their results to determine the best of VATS lobectomy for lung cancer.MethodsThis study randomized 39 consecutive patients with clinical stage I lung cancer to undergo either a complete (C-VATS, n = 20) or an assisted (A-VATS, n = 19) VATS approach for pulmonary lobectomy.ResultsThe operating time was longer (p = 0.002) and blood loss was less (p = 0.004) with C-VATS than with A-VATS. Although there was no significant difference in analgesic use or duration of thoracic drainage between the groups, a shorter hospitalization was observed after C-VATS. Serum peak levels of postoperative inflammatory markers (white blood cell count, C-reactive protein, creatine phosphokinase) were lower with C-VATS and an earlier return to normalization than with A-VATS.ConclusionVarious differences exist among the VATS lobectomy techniques, and complete VATS lobectomy as a purely endoscopic surgery may be technically feasible and a satisfactory alternative to the conventional procedure for stage I lung cancer.

A new tissue-sealing technique using the ligasure system for nonanatomical pulmonary resection: preliminary results of sutureless and stapleless thoracoscopic surgery

PURPOSE We present our initial evaluation of a new surgical technique of lung tissue sealing for nonanatomical pulmonary resection composed of sutureless and stapleless thoracoscopic surgery. DESCRIPTION Twelve patients who required therapeutic thoracoscopic pulmonary resection from April 2001 to April 2002 were recruited for this study. Resection of lung parenchyma was performed with an ultrasound-driven scalpel, and the cut end was sealed using LigaSure, a new bipolar system. Measurement of the cut surface after resection during the surgery and assessment of LigaSure sealing strength was performed. EVALUATION There were no deaths or major intraoperative complications. The mean operation time was 65 minutes, and mean hemorrhage volume was 46 mL. Average chest drain duration was 3 days, and average hospital stay was 6 days. One patient with a giant bulla and cut surface diameter of 50 mm experienced persistent air leak for 1 week. Late complications did not occur over the 8-month follow-up period. CONCLUSIONS Video-assisted thoracoscopic surgery pulmonary resection using LigaSure instead of staplers appears technically feasible and easy, and produces satisfactory preliminary results. Although further studies are required to confirm the sealing strength and reliability of LigaSure, this technique should be considered for use in nonanatomical pulmonary resections.

Local IL-17 production and a decrease in peripheral blood regulatory T cells in an animal model of bronchiolitis obliterans.

Background. Recently, it has been reported that Th17 contributes to allograft rejection after transplantation. We investigated the alteration of Th17 and regulatory T cells (Treg) distribution in an animal model of bronchiolitis obliterans following ectopic tracheal transplantation model. Methods. Tracheal grafts from B6 mice transplanted into subcutaneous sites of C3H mice. Allografts were histologically evaluated, and expressions of CD4, CD8, CD25, CD28, CD127, CD152 and Foxp3, and intracellular interleukin (IL)-4, -6, -17, and interferon-&ggr;, in peripheral blood lymphocytes were analyzed. Tracheal graft IL-6 and -17 mRNA expression was assessed using a quantitative reverse-transcriptase polymerase chain reaction. All the data in allogenic transplantation was compared with those in isograft controls. In addition, the effect of IL-6 neutralization on the allograft was evaluated with histopathology and the IL-17 mRNA expression. Results. Treg was significantly lower in peripheral blood of allogenic mice, whereas no significant difference in Th17 in the CD4+ T-cell population was observed after allogenic or isogenic transplantation. Locoregional histologic examination revealed the presence of IL-6-producing lymphocytes and endothelium in the allograft, and the luminal obliteration by fibroblast proliferation. Both IL-6 and IL-17 mRNA levels were elevated in the allograft. Severity of tracheal obliteration and IL-17 mRNA level was significantly suppressed in the IL-6 neutralized allografts. Conclusions. After allograft in a mouse bronchiolitis obliterans model, IL-17 production increases locally without an alteration in peripheral blood Th17 cells, whereas peripheral Tregs decreases. Th17 cells, which can be regulated by IL-6 stimulation, may play a role in posttransplantation rejection of the allograft.

Atrial natriuretic peptide prevents cancer metastasis through vascular endothelial cells

Significance Postoperative cancer recurrence is a major problem following curative cancer surgery. Perioperative systemic inflammation induces the adhesion of circulating tumor cells released from the primary tumor to the vascular endothelium of distant organs, which is the first step in hematogenous metastasis. We have previously reported that administration of atrial natriuretic peptide (ANP) during the perioperative period reduces inflammatory response and has a prophylactic effect on postoperative cardiopulmonary complications in lung cancer surgery. Here, we demonstrate that cancer recurrence after lung cancer surgery was significantly lower in ANP-treated patients than in control patients (surgery alone). We show that ANP prevents cancer metastasis by suppressing the inflammatory reaction of endothelial cells, thereby inhibiting cancer cell adhesion to vascular endothelial cells. Most patients suffering from cancer die of metastatic disease. Surgical removal of solid tumors is performed as an initial attempt to cure patients; however, surgery is often accompanied with trauma, which can promote early recurrence by provoking detachment of tumor cells into the blood stream or inducing systemic inflammation or both. We have previously reported that administration of atrial natriuretic peptide (ANP) during the perioperative period reduces inflammatory response and has a prophylactic effect on postoperative cardiopulmonary complications in lung cancer surgery. Here we demonstrate that cancer recurrence after curative surgery was significantly lower in ANP-treated patients than in control patients (surgery alone). ANP is known to bind specifically to NPR1 [also called guanylyl cyclase-A (GC-A) receptor]. In mouse models, we found that metastasis of GC-A–nonexpressing tumor cells (i.e., B16 mouse melanoma cells) to the lung was increased in vascular endothelium-specific GC-A knockout mice and decreased in vascular endothelium-specific GC-A transgenic mice compared with control mice. We examined the effect of ANP on tumor metastasis in mice treated with lipopolysaccharide, which mimics systemic inflammation induced by surgical stress. ANP inhibited the adhesion of cancer cells to pulmonary arterial and micro-vascular endothelial cells by suppressing the E-selectin expression that is promoted by inflammation. These results suggest that ANP prevents cancer metastasis by inhibiting the adhesion of tumor cells to inflamed endothelial cells.

IL-6 Amplifier, NF-κB–Triggered Positive Feedback for IL-6 Signaling, in Grafts Is Involved in Allogeneic Rejection Responses

The IL-6-amplifier first was discovered as a synergistic activation mechanism for NF-κB/STAT3 in type 1 collagen+ cells. This process is marked by the hyperinduction of chemokines and subsequent local inflammation that leads to autoimmune diseases. In this study, we show that IL-6 amplifier activation in grafts plays important roles in allogeneic graft rejection by using a tracheal heterotopic transplantation model that includes bronchiolitis obliterans, a pathological marker for chronic rejection. IL-6, epidermal growth factor, and IFN-γ all stimulate IL-6 amplifier activation, whereas CCL2, a chemotactic factor for Th1 cells, was one of the amplifier’s main targets. Interestingly, IFN-γ hyperinduced CCL2 in type 1 collagen+ cells via the IL-6 amplifier at least in vitro. In addition, we detected IL-6, CCL2, phospho-STAT3, and phospho-NF-κB in epithelial type 1 collagen+ cells of allogeneic tracheal grafts. These results show that IL-6 amplifier activation in grafts plays a critical role for graft rejection responses after allogeneic transplantation, including chronic rejection. From these results, we consider whether the IL-6 amplifier in grafts might be a valuable therapeutic target for the prevention of transplant rejection, including chronic rejection.

Interaction between non-small-cell lung cancer cells and fibroblasts via enhancement of TGF-β signaling by IL-6

INTRODUCTION Fibroblasts are key components of the tumor microenvironment. We clarified the role of transforming growth factor (TGF)-β and interleukin (IL)-6 in the interaction between fibroblasts and non-small-cell lung cancer (NSCLC) cells. METHODS We used NSCLC cells (A549, NCI-H358) and normal human lung fibroblast (NHLF) cells to evaluate phenotypic changes in the presence of human IL-6, TGF-β1, and conditioned media (CM) from these cells. Possible pathways were evaluated with SB431542, a TGF-β receptor inhibitor, or an anti-human IL-6 receptor neutralizing antibody (IL-6R-Ab). RESULTS A549 and NCI-H358 cells incubated with IL-6 (50 ng/mL) and TGF-β1 (2 ng/mL) showed significantly increased epithelial-mesenchymal transition (EMT) signaling compared to those treated with TGF-β1 alone. Furthermore, NHLF cells were synergistically activated by IL-6 and TGF-β1. IL-6 increased the expression of TGF-β type I receptors on the surface of A549, NCI-H358 and NHLF cells and enhanced TGF-β signaling. TGF-β1 induced phenotypic changes were attenuated by IL-6R-Ab. NHLF cells were activated and A549 cells showed induction of EMT in response to CM from the other cell type. These activities were attenuated by SB431542 or IL-6R-Ab, suggesting that interplay between NSCLC cells and NHLF may lead to increased EMT signaling in NSCLC cells and activation of NHLF cells through TGF-β and IL-6 signaling. Subcutaneous co-injection of A549 and NHLF cells into mice resulted in a high rate of tumor formation compared with injection of A549 cells without NHLF cells. SB431542 or IL-6R-Ab also attenuated the tumor formation enhanced by co-injection of the two cell types. CONCLUSION IL-6 enhanced epithelial cell EMT and stimulated tumor progression by enhancing TGF-β signaling. IL-6 and TGF-β may play a contributing role in maintenance of the paracrine loop between these two cytokines in the communication between fibroblasts and NSCLC cells for tumor progression.

The oncological feasibility and limitations of video-assisted thoracoscopic thymectomy for early-stage thymomas

OBJECTIVES Although video-assisted thoracoscopic thymectomy (VATS-Tx) for thymoma has been introduced, its oncological outcome remains unclear. Our institutional experience with early-stage thymoma was retrospectively reviewed to evaluate the oncological feasibility of thoracoscopic thymectomy. METHODS A retrospective review consisting of 74 patients with Masaoka Stage I and II thymomas who had undergone thymectomy was performed. Forty-five patients underwent thoracoscopic thymectomy, while 29 underwent thymectomy through the open sternotomy approach. The clinical factors associated with the surgical outcome, including tumour recurrence, were investigated. RESULTS Neither operative death nor major postoperative complications were observed. The median intraoperative blood loss and operative time of thoracoscopic thymectomy were 50 ml and 180 min, respectively. Among the patients with thymomas >5 cm, the number of patients with operative time >4 h was 9 of 26 (34.6%) in the thoracoscopic thymectomy and 1 of 21 (4.8%) in the open sternotomy groups. Pleural recurrence was observed in 3 (6.7%) patients with thymoma >5 cm only in the thoracoscopic thymectomy group. Tumour capsule injury by manipulation during the operation was recorded in 2 of these 3 patients. In 2 of the 3 cases who had tumours with cystic portions on computed tomography, a tumour capsule injury occurred due to manipulation during thoracoscopic thymectomy. CONCLUSIONS VATS-Tx for early-stage thymomas is feasible, while the indications should be carefully considered in patients with large or cystic tumours. The conventional open sternotomy approach could be recommended in patients with thymomas >5 cm to avoid capsule injury.

Immunology Mini-review: The Basics of TH17 and Interleukin-6 in Transplantation

The outcomes of organ transplantation are determined by graft rejection, the mechanisms of which are some of the most important areas of study in the transplantation field. The main cause of rejection is the immunologic response of the recipient toward the transplanted organ. The immunologic responses are regulated by T-cell subsets, especially helper T-cells, which have been characterized as T(H)1 or T(H)2 cells according to their profiles of cytokines production. A unique subset of recently identified lymphocytes, the regulatory T cells (T(reg)s), seem to play a role in tolerance. The recently identified T(H)17 cells are a subset of effector-helper lymphocytes that specifically secrete interleukin (IL) 17. Interestingly, T(H)17 and T(reg) both develop from naïve T cells on stimulation by transforming growth factor β. The difference is only the existence of IL-6, a proinflammatory cytokine. T(H)17 clears pathogens that are not adequately handled by T(H)1 and T(H)2 elements, as well as contributing to autoimmune diseases, such as rheumatoid arthritis, systemic lupus erythematosus, and inflammatory diseases. Autoimmune diseases are caused by reactions to self-antigens. T(H)17 (or IL-17) and IL-6 are also thought to be involved in rejection after organ transplantation. We examined the contributions of T(H)17 and IL-6 in bronchiolitis obliterans (BO), the histologic finding in chronic rejection of lung transplantations. Earlier studies have reported that T(H)17 and IL-6 contribute not only to chronic rejection of lung transplantations, but also to the rejection of other solid organs, e.g., heart, liver, and kidney. In addition, prospective avenues of research on T(H)17 and IL-6 in transplantation have emerged from the perspectives of recent studies.

Pulmonary Fibroblasts Induce Epithelial Mesenchymal Transition and Some Characteristics of Stem Cells in Non-Small Cell Lung Cancer

BACKGROUND Fibroblasts are key components of the tumor microenvironment. The purpose of this study was to clarify the role of fibroblasts in tumor progression in non-small cell lung cancer (NSCLC). METHODS Fibroblasts isolated from surgical exploration were co-cultured with human lung adenocarcinoma cell lines. We defined fibroblasts obtained from tumors as cancer associated fibroblasts (CAFs) and those from normal lung tissue as lung normal fibroblasts (LNFs). RESULTS Expression levels of myofibroblast markers were higher in CAFs than LNFs within 5 passages in the absence of continuing interaction with carcinoma cells. Thus, we used at least 2 pairs of these CAFs and LNFs in the following experiments; conditioned medium (CM) from fibroblast-induced epithelial mesenchymal transition and acquisition of cancer stem cell-like qualities in lung cancer cells (A549 and NCI-H358), indicating that CM from fibroblasts was biologically active. Furthermore, the concentration of the transforming growth factor (TGF)-β1 was higher in CM from CAFs as compared with that from LNFs, and phenotypic changes of cancer cells by CM from CAFs were greater than those induced by CM from LNFs. These CAF-induced changes were inhibited by addition of the TGF-β inhibitor SB431542. Subcutaneous co-injection of lung cancer cells and CAFs in mice enhanced tumor growth when compared with cancer cells alone, which was attenuated by administration of SB431542. CONCLUSIONS Fibroblasts were associated with increased malignant potential and the acquisition of stem cell-like properties in NSCLC tumors. Targeting CAFs as a therapeutic strategy against cancer is an intriguing concept that would benefit from further study.