Endobronchial ultrasound with a guide sheath during bronchoscopy for peripheral pulmonary lesions.

INTRODUCTION: Radial probe endobronchial ultrasound (rEBUS) improves the diagnostic yield of peripheral pulmonary lesions (PPLs). A notable methodological limitation of rEBUS is that it does not provide real-time images during transbronchial biopsy (TBB) procedures. To overcome this limitation, a guide sheath (GS) method was developed. AREAS COVERED: This review covers the procedures and complications of rEBUS-guided TBB with a GS (EGS method). We also present the data from key randomized controlled trials (RCTs) of the EGS method and summarize the usefulness of combining the EGS method with various techniques. Finally, we discuss in which situations EGS should be used. EXPERT OPINION: A large RCT showed that the diagnostic yield of the EGS method for PPLs was significantly higher than that of rEBUS-guided TBB without a GS (non-GS method). However, since the EGS and non-GS methods each have their own advantages and disadvantages, they should be considered complementary and used flexibly in different cases. In some cases, a combination of the two may be an option. The appropriate combination of EGS with various techniques may enhance the diagnostic yield of PPLs and help prevent complications. The choice should be based on the location and texture of the target lesion, as well as operator skill, resource availability, safety, and accuracy.

Inhibition of non-homologous end joining mitigates paclitaxel resistance resulting from mitotic slippage in non-small cell lung cancer.

Mitotic slippage, which enables cancer cells to bypass cell death by transitioning from mitosis to the G1 phase without undergoing normal cytokinesis, is one likely mechanism of paclitaxel (PTX) resistance. DNA double-strand breaks (DSBs) in the G1 phase are mainly repaired through non-homologous end joining (NHEJ). Therefore, inhibiting NHEJ could augment the PTX-induced cytotoxicity by impeding the repair of PTX-induced DSBs during the G1 phase following mitotic slippage. We aimed to evaluate the effects of NHEJ inhibition on mitotic slippage after PTX treatment in non-small cell lung cancer (NSCLC). H1299, A549, H1975, and H520 NSCLC cell lines were employed. In addition, A-196 and JQ1 were used as NHEJ inhibitors. H1299 cells were PTX-resistant and exhibited an increased frequency of mitotic slippage upon PTX treatment. NHEJ inhibitors significantly augmented the PTX-induced cytotoxicity, DSBs, and apoptosis in H1299 cells. The newly generated PTX-resistant cells were even more prone to mitotic slippage following PTX treatment and susceptible to the combined therapy. Docetaxel further demonstrated synergistic effects with the NHEJ inhibitor in PTX-resistant cells. NHEJ inhibition may overcome intrinsic or acquired PTX resistance resulting from mitotic slippage by synergistically increasing the cytotoxic effects of antimitotic drugs in NSCLC.

EGFR inhibition in EGFR-mutant lung cancer cells perturbs innate immune signaling pathways in the tumor microenvironment.

Epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) elicit potent cell cycle arrest in EGFR-mutant non-small-cell lung cancer (NSCLC) cells. However, little is known about the mechanisms through which these drugs alter the tumor phenotype that contributes to the immune escape of EGFR-mutant cells. Using EGFR-mutant NSCLC cell lines and tissue samples from patients, we investigated the changes in immune checkpoints expressed in tumor cells following EGFR inhibition. Subsequently, we also analyzed the role of soluble factors from the dying tumor cells in the activation of immune signaling pathways involved in therapy resistance. Upon EGFR-TKI treatment, we found that EGFR-mutant cells upregulated the expression of innate immune checkpoint CD24 in vitro. We then analyzed biopsy samples from six patients who developed resistance to a first-generation EGFR-TKI without the acquired T790M mutation. Immunohistochemistry revealed that levels of tumor CD24 expression were increased upon treatment compared with those from pre-treatment samples. Monocyte-derived macrophages facilitated antibody-dependent cellular phagocytosis when EGFR-TKI-treated EGFR-mutant cells were incubated with anti-CD24 antibodies in vitro, suggesting that CD24 may be a therapeutical target for EGFR-mutant lung cancer. Moreover, EGFR inhibition accelerated the release of cell-free DNA (cfDNA) from dying tumor cells, which activated the type I interferon signaling pathways in human THP-1 monocytes in a stimulator of interferon genes-dependent manner. Our study indicates that EGFR inhibition in EGFR-mutant NSCLC cells fosters a tumor microenvironment associated with immune escape. Thus, CD24 targeted therapy and cfDNA monitoring may contribute to improved treatment outcomes in patients with EGFR-mutant NSCLC.

Risk of bleeding associated with transbronchial biopsy using flexible bronchoscopy in patients with echocardiographic or chest CT evidence of pulmonary hypertension.

BACKGROUND: Endobronchial ultrasound (EBUS)-guided transbronchial biopsy (TBB) facilitates the diagnosis of various respiratory diseases. The safety of performing EBUS-guided TBB in patients with a finding of pulmonary hypertension (PH) is controversial. Little is known about the relationship between the risk of bleeding associated with EBUS-guided TBB in the presence of PH suspected on echocardiography or chest CT. METHODS: To assess the risk of bleeding associated with EBUS-guided TBB in patients with presumed PH per echocardiography or chest CT, we retrospectively reviewed the medical records of 314 consecutive patients who underwent EBUS-guided TBB using a guide sheath (GS), as well as echocardiography and chest CT. Bleeding complication was defined as over one minute of suctioning; repeated wedging of the bronchoscope; instillation of cold saline, diluted vasoactive substances, or thrombin due to persistent bleeding. Findings of suspected PH were defined as peak tricuspid regurgitation velocity (TRV) > 2.8 m/s on echocardiography or pulmonary artery to aorta ratio (PA:A ratio) > 0.9 on chest CT. RESULTS: In total, 35 (11.1%) patients developed bleeding, and all cases were managed safely. Furthermore, 17 (5.4%) and 59 (18.8%) patients were suspected to have PH based on echocardiography and chest CT, respectively. Among the patients suspected to have PH on echocardiography, five (5/17 = 29.4%) patients developed bleeding. Among the patients suspected to have PH on chest CT, 11 (11/59 = 18.6%) patients developed bleeding. Univariate analysis revealed that long diameter (≥ 30 mm) of the lesion, lesion location (the biopsy site was inner than the segmental bronchus), bronchoscopic diagnosis of malignancy, and additional biopsy were potential predictive factors for bleeding. The finding of suspected PH on echocardiography correlated significantly with bleeding (p = 0.03). On multivariate analysis, long diameter (≥ 30 mm) of the lesion (p = .021) and findings of suspected PH on echocardiography (p = .049) were significantly associated with bleeding. CONCLUSION: All cases of bleeding in the present study were managed safely. The risk of bleeding is moderately elevated when PH is suspected by echocardiography in patients undergoing EBUS-guided TBB using a GS.

Clinical Significance of Tumor Markers for Advanced Thymic Carcinoma: A Retrospective Analysis from the NEJ023 Study.

The optimal tumor marker for predicting the prognosis of advanced thymic carcinoma (ATC) remains unclear. We conducted a multi-institutional retrospective study of patients with ATC. A total of 286 patients were treated with chemotherapy. Clinicopathological information, including serum tumor markers, was evaluated to determine the overall survival (OS) and progression-free survival (PFS). The carcinoembryonic antigen, cytokeratin-19 fragment, squamous cell carcinoma (SCC) antigen, progastrin-releasing peptide, neuron-specific enolase (NSE), and alpha-fetoprotein levels were evaluated. In the Kaplan-Meier analysis, the OS was significantly shorter in the patients with elevated NSE levels than in those with normal NSE levels (median, 20.3 vs. 36.8 months; log-rank test p = 0.029; hazard ratio (HR), 1.55; 95% confidence interval (CI), 1.05-2.31 (Cox proportional hazard model)); a similar tendency regarding the PFS was observed (median, 6.4 vs. 11.0 months; log-rank test p = 0.001; HR, 2.04; 95% CI, 1.31-3.18). No significant differences in the OS and PFS were observed among the other tumor markers. In both univariate and multivariate analyses of the patients with SCC only, the NSE level was associated with the OS and PFS. Thus, the NSE level may be a prognostic tumor marker for thymic carcinoma, regardless of histology.

A phase I/II study of osimertinib in EGFR exon 20 insertion mutation-positive non-small cell lung cancer.

OBJECTIVES: Several preclinical data proposed a potential efficacy of osimertinib, a third-generation EGFR tyrosine kinase inhibitor, for EGFR exon 20 insertion (EGFR ex20ins)-positive non-small cell lung cancer (NSCLC). However, reported case series and a retrospective study proposed controversial efficacy. The efficacy of osimertinib in EGFR ex20ins-positive NSCLC have not been well evaluated in prospective clinical trials. In this study, we performed a prospective, single-arm, multi-center, open-label, non-randomized phase I/II study to evaluate efficacy of osimertinib for EGFR ex20ins-positive NSCLC. MATERIALS AND METHODS: From August 2018 to January 2020, 14 NSCLC patients with EGFR ex20ins were enrolled, of whom 2 were excluded because they did not meet the inclusion criteria. Efficacy and safety of 80 mg osimertinib were evaluated. In addition, we performed a translational exploratory study to clarify the association of mutation type-specific drug sensitivity, osimertinib pharmacokinetic data, and clinical efficacy. RESULTS: Of the evaluated patients, none experienced objective response, 7 experienced stable disease (58.3%), and 5 experienced disease progression (41.7%). The median progression free survival (PFS) was 3.8 months, and the median overall survival was 15.8 months. Interestingly, the exploratory study demonstrated statistically significant positive correlation between plasma osimertinib concentration/in vitro IC50 ratio and PFS (R = 0.9912, P = 0.0001), highlighting the mutation type-specific concentration-dependent efficacy of osimertinib for EGFR ex20ins-positive NSCLC. CONCLUSIONS: Regular dose, 80 mg/day, of osimertinib has limited clinical activity in NSCLC patients with EGFR ex20ins. The translational study proposed the potential efficacy of higher dose osimertinib in a subgroup of EGFR ex20ins-positive NSCLC.

Surgical treatment for tracheal stent prolapse in a patient with blunt tracheal trauma.

Blunt tracheal injury is a rare but life-threatening condition. Several indications for treatment have been reported. Conservative treatment (i.e., stenting) can be performed when the patient is clinically stable or has medical contraindications to surgical treatment. Although some studies have reported the use of tracheal stents as treatment for iatrogenic injury and blunt trauma, the efficacy of these stents is unknown. Herein, we report a case of emergency tracheoplasty for the management of tracheal stent prolapse in a patient with blunt tracheobronchial trauma. This report highlights the necessity of being cautious about the migration and prolapse of tracheal stents, which can more frequently occur in blunt trauma than in malignant stenosis or iatrogenic injury. Due to the limitations of non-surgical treatments, early surgical intervention may be lifesaving.

Evaluating the immunoproteasome as a potential therapeutic target in cisplatin-resistant small cell and non-small cell lung cancer.

PURPOSE: We evaluated the expression of proteasome subunits to assess whether the proteasome could be a therapeutic target in cisplatin-resistant lung cancer cells. METHODS: Cisplatin-resistant (CR) variants were established from three non-small cell lung cancer (NSCLC) cell lines (A549, H1299, and H1975) and two small cell lung cancer (SCLC) cell lines (SBC3 and SBC5). The expression of proteasome subunits, the sensitivity to immunoproteasome inhibitors, and 20S proteasomal proteolytic activity were examined in the CR variants of the lung cancer cell lines. RESULTS: All five CR cell lines highly expressed one or both of the immunoproteasome subunit genes, PSMB8 and PSMB9, while no clear trend was observed in the expression of constitutive proteasome subunits. The CR cells expressed significantly higher levels of PSMB8 and PSMB9 proteins, as well. The CR variants of the H1299 and SBC3 cell lines were more sensitive to immunoproteasome inhibitors, and had significantly more proteasomal proteolytic activity than their parental counterparts. CONCLUSIONS: The immunoproteasome may be an effective therapeutic target in a subset of CR lung cancers. Proteasomal proteolytic activity may be a predictive marker for the efficacy of immunoproteasome inhibitors in cisplatin-resistant SCLC and NSCLC.

Bromodomain and extraterminal domain inhibition synergizes with WEE1-inhibitor AZD1775 effect by impairing nonhomologous end joining and enhancing DNA damage in nonsmall cell lung cancer.

Bromodomain and extraterminal domain (BET) inhibitors are broadly active against distinct types of cancer, including nonsmall cell lung cancer (NSCLC). Previous studies have addressed the effect of BET-inhibiting drugs on the expression of oncogenes such as c-Myc, but DNA damage repair pathways have also been reported to be involved in the efficacy of these drugs. AZD1775, an inhibitor of the G2-M cell cycle checkpoint kinase WEE1, induces DNA damage by promoting premature mitotic entry. Thus, we hypothesized that BET inhibition would increase AZD1775-induced cytotoxicity by impairing DNA damage repair. Here, we demonstrate that combined inhibition of BET and WEE1 synergistically suppresses NSCLC growth both in vitro and in vivo. Two BET inhibitors, JQ1 and AZD5153, increased and prolonged AZD1775-induced DNA double-strand breaks (DSBs) and concomitantly repressed genes related to nonhomologous end joining (NHEJ), including XRCC4 and SHLD1. Furthermore, pharmaceutical inhibition of BET or knockdown of the BET protein BRD4 markedly diminished NHEJ activity, and the BET-inhibitor treatment also repressed myelin transcription factor 1 (MYT1) expression and promoted mitotic entry with subsequent mitotic catastrophe when combined with WEE1 inhibition. Our findings reveal that BET proteins, predominantly BRD4, play an essential role in DSB repair through the NHEJ pathway, and further suggest that combined inhibition of BET and WEE1 could serve as a novel therapeutic strategy for NSCLC.

DLL3 regulates the migration and invasion of small cell lung cancer by modulating Snail.

Delta-like protein 3 (DLL3) is a ligand of Notch signaling, which mediates cell-fate decisions and is tumor-suppressive or oncogenic depending on the cellular context. Previous studies show that DLL3 is highly expressed in small cell lung cancer (SCLC) but not in normal lung tissue, suggesting that DLL3 might be associated with neuroendocrine tumorigenesis. However, its role in SCLC remains unclear. To investigate the role of DLL3 in tumorigenesis in SCLC, we performed loss-of-function and gain-of-function assays using SCLC cell lines. In vitro analysis of cell migration and invasion by transwell assay showed that DLL3 knockdown reduced migration and invasion of SCLC cells, whereas DLL3 overexpression increased these activities. In addition, DLL3 positively regulated SNAI1 expression and knockdown of SNAI1 attenuated the migration and invasion ability of SCLC cells. Moreover, upregulated DLL3 expression induced subcutaneous tumor growth in mouse models. These results indicate that DLL3 promoted tumor growth, migration and invasion in an SCLC model by modulating SNAI1/Snail.

Clinicopathologic Features and Immune Microenvironment of Non-Small-cell Lung Cancer With Primary Resistance to Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors.

BACKGROUND: Approximately 20% to 30% of non-small-cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR)-activating mutations are not responsive to EGFR tyrosine kinase inhibitors (TKIs). Although primary resistance to EGFR-TKIs has been attributed to various genetic alterations, little is known about the clinical and immunopathologic features of patients with primary resistance. The tumor immune microenvironment, including tumor-infiltrating lymphocytes (TILs) and programmed cell death ligand 1 (PD-L1), has been reported to play an important role in tumor progression in those with NSCLC. However, few studies have directly focused on the relationship between the tumor immune microenvironment and primary resistance to EGFR-TKIs. MATERIALS AND METHODS: The characteristics of 124 NSCLC patients with EGFR mutations who had received EGFR-TKIs were analyzed. Primary resistance was defined as disease progression within 3 months after EGFR-TKI treatment. Tumor specimens obtained before EGFR-TKI treatment were assessed for the density of TILs expressing CD4 or CD8 and for the expression rate of PD-L1 on tumor cells and tumor-infiltrating immune cells, immunohistochemically. RESULTS: Primary resistance was observed in 13.7% of the patients (17 of 124). A significant difference in smoking history was observed between patients with primary resistance and those with non-primary resistance. A lower density of total TILs and negative PD-L1 expression on immunohistochemical analysis correlated significantly with primary resistance, in contrast to that with non-primary resistance. Moreover, the negative PD-L1 expression with low TIL density, indicating immune ignorant phenotype of tumor microenvironment, was observed in those with primary resistance with a significant difference. CONCLUSION: Smoking and immune ignorance in the tumor microenvironment might result in primary resistance to EGFR-TKIs.

Prognostic Factors and Efficacy of First-Line Chemotherapy in Patients with Advanced Thymic Carcinoma: A Retrospective Analysis of 286 Patients from NEJ023 Study.

BACKGROUND: The prognostic factors and the efficacy of first-line chemotherapy remain unclear in patients with advanced thymic carcinoma. MATERIALS AND METHODS: We conducted a multi-institutional retrospective study named NEJ023 for patients with advanced thymic carcinoma. All patients without any indication of curative treatment were treated with chemotherapy from 1995 to 2014 at 40 institutions of the North East Japan Study Group. RESULTS: A total of 286 patients with advanced thymic carcinoma were analyzed. First-line chemotherapy included platinum-based doublets in 62.2% of the patients, monotherapy in 3.5%, and other multidrug chemotherapy (e.g., cisplatin, doxorubicin, vincristine, and cyclophosphamide [ADOC]) in 34.3%. The median follow-up period was 55.5 months, and the median overall survival (OS) from the start of first-line chemotherapy was 30.7 months (95% confidence interval, 25.9-35.9 months). There was no significant difference in OS among different first-line chemotherapy regimens (e.g., between carboplatin/paclitaxel and ADOC, median OS: 27.8 vs. 29.9 months). Masaoka-Koga stage IVa and volume reduction surgery were favorable prognostic factors for OS in the multivariate analysis using the Cox proportional hazards model. CONCLUSION: The efficacy of each first-line chemotherapy regimen for advanced thymic carcinoma did not vary significantly. Our results might support the adequacy of the use of carboplatin/paclitaxel as first-line chemotherapy for these patients. IMPLICATIONS FOR PRACTICE: Because of its rarity, there is limited information about prognostic factors and efficacy of chemotherapy in patients with advanced thymic carcinoma. This is the largest data set for those patients treated with chemotherapy. This study suggests there is no significant difference in efficacy between carboplatin/paclitaxel and cisplatin/doxorubicin/vincristine/cyclophosphamide for advanced thymic carcinoma. This result can support the adequacy of the selection of platinum doublets as treatment for those patients, rather than anthracycline-based multidrug regimen.

Successful Application of Edoxaban in the Treatment of Venous Thromboembolism Recurrence in a Patient with Non-small Cell Lung Cancer after Tumor Shrinkage.

This report describes the case of a 66-year-old man with non-small cell lung cancer and venous thromboembolism (VTE). Unfractionated heparin (UFH) was initially used to control VTE before chemotherapy. However, switching UFH to warfarin or edoxaban, a novel oral anticoagulant (NOAC), failed. Chemotherapy was then administered to control the tumor which was thought to have been the main cause of VTE, which had been treated by UFH. After tumor shrinkage was achieved by chemotherapy, we were able to successfully switch from UFH to edoxaban. Controlling the tumor size and activity enabled the use of edoxaban as maintenance therapy for VTE.

Diversities and similarities in pH dependency among bacterial NhaB-like Na+/H+ antiporters.

NhaB-like antiporters were the second described class of Na(+)/H(+) antiporters, identified in bacteria more than 20 years ago. While nhaB-like gene sequences have been found in a number of bacterial genomes, only a few of the NhaB-like antiporters have been functionally characterized to date. Although earlier studies have identified a few pH-sensitive and -insensitive NhaB-like antiporters, the mechanisms that determine their pH responses still remain elusive. In this study, we sought to investigate the diversities and similarities among bacterial NhaB-like antiporters, with particular emphasis on their pH responsiveness. Our phylogenetic analysis of NhaB-like antiporters, combined with pH profile analyses of activities for representative members of several phylogenetic groups, demonstrated that NhaB-like antiporters could be classified into three distinct types according to the degree of their pH dependencies. Interestingly, pH-insensitive NhaB-like antiporters were only found in a limited proportion of enterobacterial species, which constitute a subcluster that appears to have diverged relatively recently among enterobacterial NhaB-like antiporters. Furthermore, kinetic property analyses of NhaB-like antiporters at different pH values revealed that the degree of pH sensitivity of antiport activities was strongly correlated with the magnitude of pH-dependent change in apparent Km values, suggesting that the dramatic pH sensitivities observed for several NhaB-like antiporters might be mainly due to the significant increases of apparent Km at lower pH. These results strongly suggested the possibility that the loss of pH sensitivity of NhaB-like antiporters had occurred relatively recently, probably via accumulation of the mutations that impair pH-dependent change of Km in the course of molecular evolution.