Mechanistic perspectives on anti-aminoacyl-tRNA synthetase syndrome.

Antisynthetase syndrome (ASSD) is an autoimmune disease characterized by circulating autoantibodies against one of eight aminoacyl-tRNA synthetases (aaRSs). Although these autoantibodies are believed to play critical roles in ASSD pathogenesis, the nature of their roles remains unclear. Here we describe ASSD pathogenesis and discuss ASSD-linked aaRSs - from the WHEP domain that may impart immunogenicity to the role of tRNA in eliciting the innate immune response and the secretion of aaRSs from cells. Through these explorations, we propose that ASSD pathogenesis involves the tissue-specific secretion of aaRSs and that extracellular tRNAs or tRNA fragments and their ability to engage Toll-like receptor signaling may be important disease factors.

Inflammatory platelet production stimulated by tyrosyl-tRNA synthetase mimicking viral infection.

Platelets play a role not only in hemostasis and thrombosis, but also in inflammation and innate immunity. We previously reported that an activated form of tyrosyl-tRNA synthetase (YRSACT) has an extratranslational activity that enhances megakaryopoiesis and platelet production in mice. Here, we report that YRSACT mimics inflammatory stress inducing a unique megakaryocyte (MK) population with stem cell (Sca1) and myeloid (F4/80) markers through a mechanism dependent on Toll-like receptor (TLR) activation and type I interferon (IFN-I) signaling. This mimicry of inflammatory stress by YRSACT was studied in mice infected by lymphocytic choriomeningitis virus (LCMV). Using Sca1/EGFP transgenic mice, we demonstrated that IFN-I induced by YRSACT or LCMV infection suppressed normal hematopoiesis while activating an alternative pathway of thrombopoiesis. Platelets of inflammatory origin (Sca1/EGFP+) were a relevant proportion of those circulating during recovery from thrombocytopenia. Analysis of these "inflammatory" MKs and platelets suggested their origin in myeloid/MK-biased hematopoietic stem cells (HSCs) that bypassed the classical MK-erythroid progenitor (MEP) pathway to replenish platelets and promote recovery from thrombocytopenia. Notably, inflammatory platelets displayed enhanced agonist-induced activation and procoagulant activities. Moreover, myeloid/MK-biased progenitors and MKs were mobilized from the bone marrow, as evidenced by their presence in the lung microvasculature within fibrin-containing microthrombi. Our results define the function of YRSACT in platelet generation and contribute to elucidate platelet alterations in number and function during viral infection.

Mechanisms of anti-GPIbα antibody-induced thrombocytopenia in mice.

Immune thrombocytopenia (ITP) is an acquired bleeding disorder characterized by antibody-mediated platelet destruction. Different mechanisms have been suggested to explain accelerated platelet clearance and impaired thrombopoiesis, but the pathophysiology of ITP has yet to be fully delineated. In this study, we tested 2 mouse models of immune-mediated thrombocytopenia using the rat anti-mouse GPIbα monoclonal antibody 5A7, generated in our laboratory. After a single IV administration of high-dose (2 mg/kg) 5A7, opsonized platelets were rapidly cleared from the circulation into the spleen and liver; this was associated with rapid upregulation of thrombopoietin (TPO) messenger RNA. In contrast, subcutaneous administration of low-dose 5A7 (0.08-0.16 mg/kg) every 3 days gradually lowered the platelet count; in this case, opsonized platelets were observed only in the spleen, and TPO levels remained unaltered. Interestingly, in both models, the 5A7 antibody was found on the surface of, as well as internalized to, bone marrow megakaryocytes. Consequently, platelets generated in the chronic phase of repeated subcutaneous 5A7 administration model showed reduced GPIbα membrane expression on their surface. Our findings indicate that evaluation of platelet surface GPIbα relative to platelet size may be a useful marker to support the diagnosis of anti-GPIbα antibody-induced ITP.

The impact of aberrant von Willebrand factor-GPIbα interaction on megakaryopoiesis and platelets in humanized type 2B von Willebrand disease model mouse.

Type 2B von Willebrand disease (VWD) is caused by gain-of-function mutations in von Willebrand factor (VWF). Increased VWF affinity for GPIba results in loss of high molecular weight multimers and enhanced platelet clearance, both contributing to the bleeding phenotype. Severity of the symptoms vary among type 2B VWD patients, with some developing thrombocytopenia only under stress conditions. Efforts have been made to study underlying pathophysiology for platelet abnormalities, but animal studies have been limited because of species specificity in the VWF-GPIba interaction. Here, we generated a severe form of type 2B VWD (p.V1316M) knockin mice in the context of human VWF exon 28 (encoding A1 and A2 domains) and crossed them with human GPIba transgenic strain. Heterozygous mutant mice recapitulated the phenotype of type 2B VWD in autosomal dominant manner and presented severe macrothrombocytopenia. Of note, platelets remaining in the circulation had extracytoplasmic GPIba shed-off from the cell surface. Reciprocal bone marrow transplantation determined mutant VWF produced from endothelial cells as the major cause of the platelet phenotype in type 2B VWD mice. Moreover, altered megakaryocyte maturation in the bone marrow and enhanced extramedullary megakaryopoiesis in the spleen were observed. Interestingly, injection of anti-VWF A1 blocking antibody (NMC-4) not only ameliorated platelet count and GPIba expression, but also reversed MK ploidy shift. In conclusion, we present a type 2B VWD mouse model with humanized VWF-GPIba interaction which demonstrated direct influence of aberrant VWF-GPIba binding on megakaryocytes.

Tyrosyl-tRNA synthetase stimulates thrombopoietin-independent hematopoiesis accelerating recovery from thrombocytopenia.

New mechanisms behind blood cell formation continue to be uncovered, with therapeutic approaches for hematological diseases being of great interest. Here we report an enzyme in protein synthesis, known for cell-based activities beyond translation, is a factor inducing megakaryocyte-biased hematopoiesis, most likely under stress conditions. We show an activated form of tyrosyl-tRNA synthetase (YRSACT), prepared either by rationally designed mutagenesis or alternative splicing, induces expansion of a previously unrecognized high-ploidy Sca-1+ megakaryocyte population capable of accelerating platelet replenishment after depletion. Moreover, YRSACT targets monocytic cells to induce secretion of transacting cytokines that enhance megakaryocyte expansion stimulating the Toll-like receptor/MyD88 pathway. Platelet replenishment by YRSACT is independent of thrombopoietin (TPO), as evidenced by expansion of the megakaryocytes from induced pluripotent stem cell-derived hematopoietic stem cells from a patient deficient in TPO signaling. We suggest megakaryocyte-biased hematopoiesis induced by YRSACT offers new approaches for treating thrombocytopenia, boosting yields from cell-culture production of platelet concentrates for transfusion, and bridging therapy for hematopoietic stem cell transplantation.

Correlation between CXCR4/CXCR7/CXCL12 chemokine axis expression and prognosis in lymph-node-positive lung cancer patients.

The CXCR4/CXCR7/CXCL12 chemokine axis plays important roles in the migration of tumor cells during cancer development by modulating site-specific distant metastasis including to regional lymph nodes. We investigated the correlation of these chemokine expressions to prognosis in lymph-node-positive non-small-cell lung cancer (NSCLC) patients. A total of 140 surgically resected specimens of primary site (PS) and metastatic lymph nodes (MLN) of NSCLC involving hilar and/or mediastinal lymph nodes (N1-2) were collected. CXCR4, CXCR7 and CXCL12 expressions were evaluated. Cox regression analysis was performed to determine whether these chemokines were independent prognostic factors in N1-2 NSCLC. High expression of CXCR4 in PS and CXCL12 in MLN was associated with poor overall survival (OS) (P = .025 and .033, respectively). Significant correlations between CXCR4 expression in PS and CXCL12 expression in MLN were observed (P = .040). There was significant difference in OS between 2 groups according to expressions of CXCR4 in PS and CXCL12 in MLN (P = .0033). Expression of CXCL12 in MLN was identified as an independent prognostic factor (HR 1.79, 95% CI 1.08-3.04, P = .023). CXCL12 in MLN was mainly expressed by tumor cells compared with stromal cells (56% vs 25%, respectively, P < .0001). CXCR4/CXCL12 may play roles in tumor progression in MLN and is associated with poor prognosis of lymph-node-positive NSCLC patients.

Underlying Problems in Surgical Treatment of cT1-2N1 Non-Small Cell Lung Cancer.

Background Obtaining an accurate preoperative diagnosis of N1 in non-small cell lung cancer (NSCLC) is a major difficulty. The aim of this retrospective study was to evaluate the pathological and long-term outcomes of NSCLC patients clinically staged with N1 disease, to aid in the search for better treatment strategies. Materials and Methods We retrospectively reviewed the clinical records of 1,180 consecutive patients with NSCLC who underwent surgery for curative intent from 1991 to 2011 in our department. Data on 96 (8.1%) patients who had cT1-2N1 disease and underwent lobectomy or more extensive surgery were available. Results Only 32% of patients (n = 31) were confirmed to have pathological N1 disease, and 34 and 33% of patients were proven to have pN0 and pN2 disease, respectively. Female gender, ≤ 30 pack-year tobacco smoking history, adenocarcinoma, and left-sided disease were significantly associated with pathological upstaging (χ2 test). Multivariate analysis using logistic regression revealed left-sided disease to be independently associated with upstaging (relative risk 4.00, p = 0.015). Left-sided disease was more likely to be underestimated by clinical N staging than right-sided disease (χ2 test, p = 0.0001). Univariate and multivariate survival analyses demonstrated that left-sided disease was an independent prognostic factor associated with poor outcomes (Cox proportional hazards regression: hazard ratio 2.27, p = 0.037). Conclusion The diagnostic accuracy of clinical N1 status was poor. Left-sided disease appeared to be understaged by the preoperative assessment of N status, and therefore, patients who might benefit from preoperative induction treatment would not receive it.

Prognostic Significance of Expression of the Epithelial-Mesenchymal Transition-Related Factor Brachyury in Intrathoracic Lymphatic Spread of Non-Small Cell Lung Cancer.

BACKGROUND: Brachyury is a transcriptional regulator that plays important roles in epithelial mesenchymal transition (EMT) during development and has been reported to be essential for mesoderm formation in the early human embryo. We investigated Brachyury protein expression in hilar and mediastinal metastatic lymph nodes of non-small cell lung cancer patients and the prognostic significance of Brachyury expression at metastatic sites. METHODS: Expression of Brachyury in 115 surgically resected primary lung cancer and corresponding metastatic lymph node samples was evaluated by immunohistochemical staining. The relationships between Brachyury protein expression and the patient's clinicopathological factors and prognosis were analyzed. RESULTS: Brachyury expression in metastatic lymph nodes was significantly higher than that in the primary tumor (p = 0.012). Patients with high Brachyury expression in the metastatic lymph nodes had significantly poor prognoses (p = 0.0236) compared with patients with low expression. In addition, patients with larger differences in Brachyury expression between metastatic lymph nodes and the primary tumor had significantly poorer prognoses compared with patients with smaller differences (p = 0.0146). The Brachyury protein expression level in metastatic lymph nodes was significantly associated with the protein expression levels of other EMT-related factors (E-cadherin [inverse association], p = 0.0265; Slug, p = 0.029; and interleukin-8, p = 0.0135). CONCLUSIONS: High expression of Brachyury protein in metastatic carcinoma cells in the intrathoracic lymph nodes was associated with poor prognosis of lung cancer patients. Increased Brachyury expression during the metastatic process may confer further potential for invasion and metastasis of cancer cells.

Case of a Cardiopulmonary Arrest Due to Postoperative Subglottic Stenosis Developed on the Second Day after Lung Surgery.

We experienced a case of the cardiopulmonary arrest due to subglottic stenosis developed on the second day after lung cancer surgery. Case : A 73-year-old female who was diagnosed with primary lung cancer was referred to our department for surgery. The second day after left lung segmentectomy, she showed respiratory discomfort symptoms and exhibited hoarseness and stridor, which were revealed as the subglottic stenosis by bronchoscopy. During the emergency airway management, she went into cardiopulmonary arrest. We performed cardiopulmonary resuscitation and simultaneous urgent tracheotomy.

Clinical Significance of Detecting Somatic Gene Mutations in Surgically Resected Adenosquamous Cell Carcinoma of the Lung in Japanese Patients.

BACKGROUND: Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) and echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) inhibitors are effective and useful agents for treating patients who harbor EGFR-TKI-sensitive mutations or EML4-ALK rearrangement. Therefore, the importance of determining the presence of these somatic mutations when treating lung adenocarcinomas is widely accepted. However, genetic mutations are rarely evaluated in patients with adenosquamous cell carcinoma of the lung, a relatively infrequent histologic type of lung cancer, because of limited knowledge and the unclear value of assessing these oncogenic mutations in these patients. Therefore, we investigated the clinical implications of somatic mutations in surgically resected adenosquamous cell carcinoma of the lung in Japanese patients. METHODS: We retrospectively analyzed 32 patients with adenosquamous cell carcinoma of the lung who underwent surgical resection at two institutes in Japan. EGFR mutations and EML4-ALK rearrangement were assessed in all of the patients. RESULTS: Overall, 7 (21.9 %) of 32 patients had EGFR mutations: three patients had an exon 19 deletion and 4 had an exon 21, L858R mutation. There were no T790 M mutations. The median relapse-free survival was 766 days and the median overall survival was 1,152 days in the total cohort. Relapse-free survival and overall survival were not significantly different between patients with or without EGFR mutations. CONCLUSIONS: Detecting EGFR mutations in patients with adenosquamous cell carcinoma is clinically important, especially in patients with disease recurrence because EGFR-TKIs may be effective in this histologic type of lung cancer.

Gemcitabine and vinorelbine as second-line or beyond treatment in patients with malignant pleural mesothelioma pretreated with platinum plus pemetrexed chemotherapy.

BACKGROUND: Malignant pleural mesothelioma (MPM) is an aggressive neoplasm that responds poorly to chemotherapy. Although treatment with pemetrexed in combination with cisplatin serves as first-line chemotherapy for MPM, the optimal second-line and beyond therapy has not yet been fully examined. METHODS: Between March 2008 and October 2011, 17 consecutive Japanese patients pretreated with at least one regimen of platinum plus pemetrexed chemotherapy received gemcitabine and vinorelbine. Responses, survival time, and toxicity were retrospectively evaluated. RESULTS: Response [partial response (PR) + complete response (CR)] and disease control [stable disease (SD) + PR + CR] rates were 18 and 82 %, respectively. The median progression-free survival (PFS) after combination chemotherapy was 6.0 months, whereas the median overall survival (OS) was 11.2 months. Grade 3 or 4 neutropenia and anemia were observed in 41 and 29 % of patients, respectively, and one patient experienced febrile neutropenia. Grade 3 or 4 nonhematologic toxicities included constipation (6 %) and phlebitis (6 %). CONCLUSION: Combination chemotherapy using gemcitabine with vinorelbine was shown to have moderate activity in Japanese MPM patients pretreated with platinum plus pemetrexed chemotherapy. A further multicenter phase II trial is warranted to confirm the efficacy and safety of this combination treatment.

A rare case of a bronchial anomaly running in the hilar region from the right lower lobe to the middle lobe.

A 77-year-old male was referred to our department due to lung cancer (cT3N0M0) of the right lower lobe. During right lower lobectomy, a thin duct structure was recognized in the hilar region between the middle and lower lobes that was identified to be a supernumerary bronchus upon a review of the preoperative chest CT images. Although bronchial anomalies are rare, it is important to carefully view preoperative images for any such anomalies in order to more safely perform surgery.

[Case of pulmonary inflammatory pseudotumor with cysts].

We herein report a case involving a 58-year-old female patient with multiple cystic lesions in the right lobe of the lung. The lesions were revealed on chest computed tomography in 2002 and followed up. Transbronchial lung biopsy showed no malignancy in June 2013. The lesions gradually increased in size and thickness and were associated with fluid-filled cysts. We performed a right lower lobectomy in November 2013. Pathological examination revealed inflammatory pseudotumor. Such a case of inflammatory pseudotumor presenting as a pulmonary cyst has not been previously described. Intractable infection and inflammation are regarded as common causes of inflammatory pseudotumor. This condition should be considered in patients with a medical history consistent with infectious disease and a pulmonary cyst found on chest computed tomography.

Successful resection of a giant mediastinal non-seminomatous germ cell tumor showing fluorodeoxyglucose accumulation after neoadjuvant chemotherapy: report of a case.

A 32-year-old man presented with a mediastinal non-seminomatous germ cell tumor showing fluorodeoxyglucose (FDG) accumulation (maximum standardized uptake value = 22.21) and extremely elevated blood alpha-fetoprotein (AFP) level (9203.0 ng/ml). The patient underwent 4 cycles of neoadjuvant chemotherapy (cisplatin, bleomycin, and etoposide), which normalized the AFP level and reduced the tumor size, allowing complete resection without a support of extracorporeal circulation. Despite preoperative positron emission tomography revealing increased FDG uptake in the residual tumor (maximum standardized uptake value = 3.59), the pathologic evaluation revealed that no viable germ cell tumor cells remained. We believe FDG uptake should not be used as a criterion for surgical resection after neoadjuvant chemotherapy. It is appropriate to resect the residual tumor regardless of FDG uptake after induction chemotherapy if a tumor is resectable and the AFP level normalizes.

Amrubicin as second-line and beyond treatment for platinum-refractory advanced thymic carcinoma.

OBJECTIVE: Thymic carcinoma is a rare mediastinal neoplasm, and the prognosis of patients with advanced thymic carcinoma is poor. No standard chemotherapeutic regimen has yet been established for the disease. This is the first report to evaluate the role of amrubicin, a novel anthracycline anticancer drug, in second-line and beyond treatment for patients with platinum-refractory advanced thymic carcinoma. METHODS: This study was a review of thymic carcinoma patients who had received amrubicin monotherapy between June 2003 and December 2011 for the progression of disease previously treated with platinum-based chemotherapy. Amrubicin was administered at 35 or 40 mg/m(2) for three consecutive days every 3 weeks, until progression. RESULTS: Nine patients with recurrent thymic carcinoma were registered. Their median age was 61 years (range 45-72), and the patients included five males and four females. All nine patients had Masaoka's Stage IVb disease. There were three squamous cell carcinomas, one adenocarcinoma, one small-cell carcinoma and two other histological types. The mean number of chemotherapy cycles was five (range 2-13). Grade 3 or higher toxicities included mainly neutropenia (55.5%), anemia (25.0%) and febrile neutropenia (11.1%). No treatment-related deaths were observed. The response rate was 44.4% (95% confidence interval: 19-73). The median progression-free survival after the amrubicin monotherapy was 4.9 months, while the median overall survival was 6.4 months. CONCLUSIONS: Single-agent amrubicin was found to be potentially useful as second-line and beyond chemotherapy for patients with advanced thymic carcinoma. Further multi-institutional prospective studies are warranted.

BioKnife, a uPA activity-dependent oncolytic Sendai virus, eliminates pleural spread of malignant mesothelioma via simultaneous stimulation of uPA expression.

Malignant pleural mesothelioma (MPM) is highly intractable and readily spreads throughout the surface of the pleural cavity, and these cells have been shown to express urokinase-type plasminogen activator receptor (uPAR). We here examined the potential of our new and powerful recombinant Sendai virus (rSeV), which shows uPAR-specific cell-to-cell fusion activity (rSeV/dMFct14 (uPA2), named "BioKnife"), for tumor cell killing in two independent orthotopic xenograft models of human. Multicycle treatment using BioKnife resulted in the efficient rescue of these models, in association with tumor-specific fusion and apoptosis. Such an effect was also seen on both MSTO-211H and H226 cells in vitro; however, we confirmed that the latter expressed uPAR but not uPA. Of interest, infection with BioKnife strongly facilitated the uPA release from H226 cells, and this effect was completely abolished by use of either pyrrolidine dithiocarbamate (PDTC) or BioKnife expressing the C-terminus-deleted dominant negative inhibitor for retinoic acid-inducible gene-I (RIG-IC), indicating that BioKnife-dependent expression of uPA was mediated by the RIG-I/nuclear factor-κB (NF-κB) axis, detecting RNA viral genome replication. Therefore, these results suggest a proof of concept that the tumor cell-killing mechanism via BioKnife may have significant potential to treat patients with MPM that is characterized by frequent uPAR expression in a clinical setting.

[Case of adenocarcinoma in situ accompanied by an intrapulmonary lymph node with a sarcoid-like reaction].

A 65-year-old male underwent a chest CT scan, which revealed an 8 mm nodule on the wall of a bulla in the left lower lobe of the lung, and was thus suspected to be lung cancer. Pulmonary wedge resection of the left lower lobe by means of video-assisted thoracoscopic surgery was thus performed. A specimen of the lung revealed the presence of intrapulmonary lymph node on the wall of a bulla. The histopathological findings of the resected lung specimen showed non-caseating granulomas in the lymph node, and adenocarcinoma in situ. We concluded that the sarcoid-like reaction observed in the intrapulmonary lymph node was therefore related to the adenocarcinoma in situ.

Nuclear translocation of an aminoacyl-tRNA synthetase may mediate a chronic "integrated stress response".

Various stress conditions are signaled through phosphorylation of translation initiation factor eukaryotic initiation factor 2α (eIF2α) to inhibit global translation while selectively activating transcription factor ATF4 to aid cell survival and recovery. However, this integrated stress response is acute and cannot resolve lasting stress. Here, we report that tyrosyl-tRNA synthetase (TyrRS), a member of the aminoacyl-tRNA synthetase family that responds to diverse stress conditions through cytosol-nucleus translocation to activate stress-response genes, also inhibits global translation. However, it occurs at a later stage than eIF2α/ATF4 and mammalian target of rapamycin (mTOR) responses. Excluding TyrRS from the nucleus over-activates translation and increases apoptosis in cells under prolonged oxidative stress. Nuclear TyrRS transcriptionally represses translation genes by recruiting TRIM28 and/or NuRD complex. We propose that TyrRS, possibly along with other family members, can sense a variety of stress signals through intrinsic properties of this enzyme and strategically located nuclear localization signal and integrate them by nucleus translocation to effect protective responses against chronic stress.

Prediction of true-negative lymph node metastasis in clinical IA non-small cell lung cancer by measuring standardized uptake values on positron emission tomography.

PURPOSE: We developed a method for predicting true-negative lymph node metastases in clinical IA non-small lung cancer (NSCLC) by the combined evaluation of computed tomography (CT), 2-[18F]-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) findings and the maximum standardized uptake value (SUVmax) of primary tumors. METHODS: The subjects of this study were 94 patients with clinical stage IA NSCLC who underwent both preoperative CT and FDG-PET. We analyzed the relationship between the SUVmax of primary tumors and various clinicopathological factors to find the best method available for assessing true-negative lymph node metastasis. RESULTS: The pathological stages were IA (n = 80), IB (n = 4), IIA (n = 5), IIIA (n = 4), and IV (n = 1). Pathologic lymph node metastasis was recognized in nine patients and the SUVmax of these tumors ranged from 3.3 to 20.3. A SUVmax of 3.0 was defined as the cut-off point and patients were dichotomized according to this point. Tumors with SUVmax of 3.0 or less were associated with a significantly lower incidence of pleural and vascular invasion and were characterized by the degree of differentiation. CONCLUSION: The SUVmax of primary tumors reflects the grade of malignancy; therefore, the combined evaluation of FDG-PET/CT findings with the SUVmax of primary tumors may help predict lymph node metastasis negativity.