In pathway‐targeted cancer drug therapies, the relatively rapid emergence of drug‐tolerant persisters (DTPs) substantially limits the overall therapeutic benefit. However, little is known about the roles of DTPs in drug resistance. In this study, we investigated the features of epidermal growth factor receptor–tyrosine kinase inhibitor‐induced DTPs and explored a new treatment strategy to overcome the emergence of these DTPs. We used two EGFR‐mutated lung adenocarcinoma cell lines, PC9 and II‐18. They were treated with 2 μM gefitinib for 6, 12, or 24 days or 6 months. We analyzed the mRNA expression of the stem cell‐related markers by quantitative RT‐PCR and the expression of the cellular senescence‐associated proteins. Then we sorted DTPs according to the expression pattern of CD133 and analyzed the features of sorted cells. Finally, we tried to ablate DTPs by glucose metabolism targeting therapies and a stem‐like cell targeting drug, withaferin A. Drug‐tolerant persisters were composed of at least two types of cells, one with the properties of cancer stem‐like cells (CSCs) and the other with the properties of therapy‐induced senescent (TIS) cells. The CD133high cell population had CSC properties and the CD133low cell population had TIS properties. The CD133low cell population containing TIS cells showed a senescence‐associated secretory phenotype that supported the emergence of the CD133high cell population containing CSCs. Glucose metabolism inhibitors effectively eliminated the CD133low cell population. Withaferin A effectively eliminated the CD133high cell population. The combination of phloretin and withaferin A effectively suppressed gefitinib‐resistant tumor growth.

Extracellular vesicles (EVs) are circulating vesicles secreted by various cell types. EVs are classified into three groups according to size, structural components, and generation process of vesicles: exosomes, microvesicles, and apoptotic bodies. Recently, EVs have been considered to be crucial for cell-to-cell communications and homeostasis because they contain intracellular proteins and nucleic acids. Epithelial cells from mice suffering from bronchial asthma (BA) secrete more EVs and suppress inflammation-induced EV production. Moreover, microarray analyses of bronchoalveolar lavage fluid have revealed that several microRNAs are useful novel biomarkers of BA. Mesenchymal stromal cell-derived EVs are possible candidates of novel BA therapy. In this review, we highlight the biologic roles of EVs in BA and review novel EV-targeted therapy to help understanding by clinicians and biologists.

BackgroundWe have shown that phospholipase Cε (PLCε), an effector of Ras and Rap1 small GTPases, plays pivotal roles in inflammation and inflammation-associated carcinogenesis by augmenting proinflammatory cytokine production from epithelial cells of various organs. The purpose of this study is to analyze its role in neutrophilic alveolar inflammation accompanying acute lung injury (ALI), focusing on that in alveolar epithelial cells (AECs), which are known to make a major contribution to the pathogenesis of ALI.MethodsWe examine the effect of the PLCε genotypes on the development of ALI induced by intratracheal administration of lipopolysaccharide (LPS) to PLCε wild-type (PLCε+/+) and knockout (PLCεΔX/ΔX) mice. Pathogenesis of ALI is analyzed by histological examination of lung inflammation and measurements of the levels of various cytokines, in particular neutrophil-attracting chemokines such as Cxcl5, by quantitative reverse transcription-polymerase chain reaction and immunostaining. Primary cultures of AECs, established from PLCε+/+ and PLCεΔX/ΔX mice, are used to analyze the roles of PLCε, protein kinase D (PKD) and nuclear factor-κB (NF-κB) in augmentation of LPS-induced Cxcl5 expression.ResultsCompared to PLCε+/+ mice, PLCεΔX/ΔX mice exhibit marked alleviation of lung inflammation as shown by great reduction in lung wet/dry weight ratios, accumulation of inflammatory cells in the alveolar space and thickening of alveolar walls as well as the number of neutrophils and the protein concentration in bronchoalveolar lavage fluid. Also, LPS-induced expression of the CXC family of chemokines, in particular Cxcl5, is substantially diminished in the total lung and AECs of PLCεΔX/ΔX mice. Moreover, LPS-induced Cxcl5 expression in primary cultured AECs is markedly suppressed on the PLCεΔX/ΔX background (p < 0.05 versus PLCε+/+ AECs), which is accompanied by the reduction in phosphorylation of inhibitor κB (IκB), PKD and nuclear translocation of NF-κB p65. Also, it is suppressed by the treatment with inhibitors of PKD and IκB kinase, suggesting the involvement of the PLCε-PKD-IκB-NF-κB pathway.ConclusionsPLCε-mediated augmentation of the production of the CXC family of chemokines, in particular Cxcl5, in AECs plays a crucial role in neutrophilic alveolar inflammation accompanying ALI, suggesting that PLCε may be a potential molecular target for the treatment of acute respiratory distress syndrome.Electronic supplementary materialThe online version of this article (10.1186/s12931-019-0975-4) contains supplementary material, which is available to authorized users.

Background Recent studies have revealed that serpin peptidase inhibitor clade E member 2 (SERPINE2) is associated with tumorigenesis. However, SERPINE2 expression and its role in lung adenocarcinomas are still unknown. Methods The expression levels of SERPINE2 in 74 consecutively resected lung adenocarcinomas were analyzed by using immunostaining. Inhibition of SERPINE2 expression by small interfering RNA (siRNA) was detected by quantitative PCR. Cell number assays and cell apoptosis assays were performed to clarify the cell-autonomous function of SERPINE2 in A549 and PC9 lung cancer cells. Results The overall survival of patients with high SERPINE2 expression was significantly worse than that of patients with low SERPINE2 expression (P = 0.0172). Multivariate analysis revealed that SERPINE2 expression was an independent factor associated with poor prognosis (P = 0.03237). The interference of SERPINE2 decreased cell number and increased apoptosis in A549 and PC9 cells Conclusion These results suggest that SERPINE2 can be used as a novel prognostic marker of lung adenocarcinoma.

BackgroundSphingosine kinase phosphorylates sphingosine to generate sphingosine 1 phosphate (S1P) following stimulation of the five plasma membrane G-protein-coupled receptors. The objective of this study is to clarify the role of S1P and its receptors (S1PRs), especially S1PR3 in airway epithelial cells.MethodsThe effects of S1P on asthma-related genes expression were examined with the human bronchial epithelial cells BEAS-2B and Calu-3 using a transcriptome analysis and siRNA of S1PRs. To clarify the role of CCL20 in the airway inflammation, BALB/c mice were immunized with ovalbumin (OVA) and subsequently challenged with an OVA-containing aerosol to induce asthma with or without intraperitoneal administration of anti-CCL20. Finally, the anti-inflammatory effect of VPC 23019, S1PR1/3 antagonist, in the OVA-induced asthma was examined.ResultsS1P induced the expression of some asthma-related genes, such as ADRB2, PTGER4, and CCL20, in the bronchial epithelial cells. The knock-down of SIPR3 suppressed the expression of S1P-inducing CCL20. Anti-CCL20 antibody significantly attenuated the eosinophil numbers in the bronchoalveolar lavage fluid (P<0.01). Upon OVA challenge, VPC23019 exhibited substantially attenuated eosinophilic inflammation.ConclusionsS1P/S1PR3 pathways have a role in release of proinflammatory cytokines from bronchial epithelial cells. Our results suggest that S1P/S1PR3 may be a possible candidate for the treatment of bronchial asthma.

Background Cisplatin (CDDP) and vinorelbine as an adjuvant chemotherapy improve the overall survival of patients with completely resected non‐small cell lung cancer (NSCLC). However, the treatment completion rate is low due to severe adverse events (AEs). Pemetrexed (PEM) has been used in advanced NSCLC due to its high safety and efficacy. Additionally, the safety of a short hydration method for CDDP administration has been previously reported. Here, we investigated the feasibility of CDDP plus PEM with a short hydration method as adjuvant chemotherapy. Methods A total of 21 completely resected nonsquamous NSCLC patients with pathological stage IIA to IIIA disease were enrolled into the study. Adjuvant chemotherapy consisted of four cycles of CDDP (75 mg/m2) plus PEM (500 mg/m2) every three weeks with a short hydration method. The primary endpoint was the treatment completion rate, and the secondary endpoints included toxicity, the two‐year relapse‐free survival (RFS) rate, and the outpatient treatment rate. Results A total of 21 patients (median age: 66 years; 12 males) were enrolled in two centers. All cases were adenocarcinoma with PS0 (71.4%) or PS1 (28.6%). A total of 81.0% of the patients received four cycles of therapy as scheduled and the primary endpoint was met. The rate of outpatient chemotherapy completion after the second cycle was 90.5%. The grade 3 or higher toxicities were anorexia (n = 2) and pulmonary thromboembolism (n = 1). No grade 3/4 hematological toxicities or creatinine level elevations were observed. The two‐year RFS rate was 57.3%. Conclusions CDDP and PEM with a short hydration is well tolerated in the outpatient setting with limited toxicity. Key points Significant findings of the study CDDP plus PEM adjuvant therapy with a short hydration method is well tolerated in the outpatient setting with limited toxicity. What this study adds CDDP plus PEM with a short hydration method has the potential to be one of the options of adjuvant therapy in the future.

Purpose Caspase recruitment domain-containing protein 9 (CARD9) is expressed at high levels in bone marrow cells and has a crucial role in innate immunity. Current studies indicate that CARD9 also plays a key role in tumor progression, but there are few reports on the role of CARD9 in lung cancer. The aim of this study was to clarify the role of CARD9 in lung adenocarcinoma. Patients and Methods Lung adenocarcinoma tumor samples from 74 patients who underwent complete resection at Kobe University Hospital from January 2014 to December 2014 were analyzed by immunohistochemistry. The role of CARD9 in cancer cells was analyzed using lung cancer cell lines treated with CARD9 siRNA. Results High expression of CARD9 was observed in 32.4% of tumors, and compared to low expression of CARD9, high expression was associated with poorer overall survival (P = 0.0365). Univariate and multivariate analyses showed that high expression of CARD9 was an independent prognostic factor. Knockdown of CARD9 in lung adenocarcinoma cells inhibited proliferation but did not increase apoptosis. In addition, CARD9 activated the NF-κB pathway in a lung adenocarcinoma cell line. Conclusion CARD9 was shown to be an independent prognostic factor of poor outcome for lung cancer and may represent a molecular target for treatment.

Background: The combination of gemcitabine (GEM) and paclitaxel (PTX) was appealing for clinical exploration due to different mechanisms of action and partially non-overlapping toxicities. Purpose: The aim of this study was to elucidate a potential effect of this combination on the proliferation of two non-small cell lung cancer (NSCLC) cell lines, A549 and H520. Materials and methods: Cell lines were treated with GEM and PTX for 48 hours to evaluate the half maximal inhibitory concentration (IC50). To determine the combination index (CI), cell lines were exposed to GEM and PTX, in a constant ratio of IC50, by various combination treatments. GEM`s effect on tubulin was assessed by western blotting and immunofluorescent staining. GEM was combined with nanoparticle albumin-bound-paclitaxel (NP) in evaluating tumor growth inhibition. Results: The IC50 of GEM and PTX in A549 and H520 were 6.6 nM and 46.1 nM, and 1.35 nM and 7.59 nM, respectively. Among the sequences explored (GEM→PTX, PTX→GEM, and GEM plus PTX simultaneously [GEM+PTX]), GEM→PTX produced a mean CI <1 in both cell lines. Western blotting and immunofluorescent staining revealed the intention expressions of acetylated tubulin protein and enhancement of tubulin polymerization within GEM→PTX group. A combination order GEM→NP also worked synergistically to suppress tumor growth. Conclusion: The GEM→PTX sequence may represent a promising candidate regimen for the treatment of NSLCL.