Published papers

© 2020 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association. ABT-263 (Navitoclax) is a BH3-mimetic drugs targeting anti-apoptotic B-cell lymphoma-2 (BCL-2) family proteins, including BCL-2, BCL-xL, and BCL-w, thereby inducing apoptosis. In small-cell lung cancer (SCLC) cells, the response to ABT-263 is associated with the expression of myeloid cell leukemia-1 (MCL-1) protein, however the efficacy of ABT-263 in non-small-cell lung cancer (NSCLC) has not been thoroughly evaluated. There are currently no established biomarkers for predicting the efficacy of ABT-263 treatment in NSCLC. We screened a panel of different NSCLC cell lines and found that ABT-263 inhibited cell proliferation and induced apoptosis in Calu-1, Calu-3, and BID007 cells. Inconsistent with previous reports on SCLC, low levels of MCL-1 did not predict the response to ABT-263 in NSCLC cells, however we found that intracellular levels of reactive oxygen species (ROS) in cancer cells were associated with sensitivity to ABT-263 in NSCLC cells. We also showed that increasing the level of intracellular ROS could enhance the sensitivity to ABT-263 in NSCLC cells. In summary, we propose that the intracellular levels of ROS could be used as a potential novel biomarker for predicting a response to ABT-263 in NSCLC. Furthermore, we show some evidence supporting the further assessment of ABT-263 as a new therapeutic strategy in patients with NSCLC combined with agents regulating ROS levels. We believe that our findings and follow-up studies on this matter would lead to novel diagnostic and treatment strategies in patients with NSCLC.

© 2018 Kobayashi et al. Background: Osimertinib, a third-generation epidermal growth factor receptor-tyrosine kinase inhibitor, exerts remarkable effects against EGFR T790M resistance mutation-positive non-small cell lung cancer. Identifying T790M mutation by re-biopsy is essential before prescribing osimertinib. Tissue biopsy is the golden standard for this purpose, but several factors limit its success rate. The liquid biopsy with blood, using circulating tumor DNA, has been an alternative method. However, the true biological meaning and equivalence of liquid biopsy and tumor biopsy are still under investigation. Especially, the usefulness of serum samples to detect T790M mutation is not yet been known. Patients and methods: We prospectively evaluated the sensitivity, specificity, and parallelism of the detection of EGFR mutations in tissue re-biopsy and liquid biopsy (plasma and serum), simultaneously, from June 2016 to May 2017. EGFR mutations in tumor re-biopsy were evaluated by COBAS ver2 and PNA-LNA PCR clamp method, and those in liquid biopsy were evaluated with COBAS ver2. Results: Fifteen patients were enrolled. In 10 patients whose EGFR mutation was detected in liquid biopsy, the original EGFR mutation (exon 19 del or L858R) was detected in all patients. Detection of EGFR mutation by COBAS ver2 and by PNA-LNA method was almost the same in tissue re-biopsy. The detection rate of T790M was lower than that of the original EGFR mutation in liquid biopsy compared to that in tissue re-biopsy. The detection of T790M in serum exhibited a higher specificity (67%) and positive predictive value (50%) than that in plasma (50% and 40%, respectively). The detection sensitivity was similar in plasma and serum. Conclusion: Plasma, serum, and tissue genotyping can have complementary roles for detecting EGFR-T790M using COBAS ver2. Repeated tests with different samples and different methods may improve accuracy of T790M detection and will lead to the maximum benefit for the patient.

© 2018 Elsevier B.V. Objectives: Epidermal growth factor receptor (EGFR) mutation-positive lung cancer accounts for a significant subgroup of non-small cell lung cancers (NSCLC). Approximately 4–10% of EGFR mutations in NSCLC are EGFR exon 20 insertion mutations, which are reportedly associated with resistance to EGFR tyrosine kinase inhibitor (EGFR-TKI) treatment. NSCLC patients carrying these mutations are rarely treated with EGFR-TKIs. The purpose of this study was to evaluate the efficacy of afatinib or osimertinib plus cetuximab combination therapy in experimental NSCLC models with EGFR exon 20 insertion mutations. Materials and methods: The EGFR mutations examined in this study were A763_Y764insFQEA, Y764_V765insHH, A767_V769dupASV, and D770_N771insNPG. Ba/F3 cells constitutively expressing wild type or mutated EGFR were used to determine the efficacy of afatinib or osimertinib plus cetuximab combination therapy in vitro. To determine the efficacy of the combination therapy in vivo, female BALB/c-nu mice were injected subcutaneously with 1 million Ba/F3 cells carrying EGFR A767_V769dupASV or Y764_V765insHH. Results: We observed a mild but significant (P < 0.05) additive effect of the combination therapy against several EGFR exon 20 insertion mutations in vitro. Regarding EGFR A767_V769dupASV and EGFR Y764_V765insHH, cetuximab and afatinib single treatment did not induce significant inhibition of tumor formation; however, afatinib plus cetuximab combination treatment induced significant (P < 0.05) tumor growth inhibition without significant body weight loss or skin rash. Conclusion: The combination therapy induced a more potent inhibitory effect against several EGFR exon 20 insertion mutations than either therapy alone. Cetuximab can potentially increase the efficacy of afatinib or osimertinib in NSCLC with EGFR exon 20 insertion mutations.

© 2018 American Association for Cancer Research. Purpose: EGFR exon 20 insertions account for up to 10% of all EGFR mutations in lung adenocarcinomas, representing the third most common cluster of mutations. The management of advanced cancers with these mutations remains elusive, without an approved inhibitor. Experimental Design: Preclinical models of a representative set of EGFR exon 20 insertion mutations to evaluate the efficacy of different inhibitors and description of the clinical outcome of an advanced lung cancer. Results: We show that select first-, second-, and third-generation EGFR inhibitors are unable to deter common EGFR exon 20 insertion mutants in concentrations that spare the wild-type kinase. Nonetheless, EGFR exon 20 insertion mutants associate with the Hsp90 chaperone system. We exploit this vulnerability to show that the nongeldanamycin Hsp90 inhibitor luminespib (formerly AUY922) degrades EGFR exon 20 mutations, downstream targets, and induces apoptosis. In addition, a patient whose EGFR inhibitor–insensitive lung adenocarcinoma harbored an EGFR exon 20 insertion mutation had a confirmed radiographic response to luminespib. Conclusions: The report confirms that EGFR exon 20 mutations are dependent on Hsp90 and are readily inhibited by the Hsp90 inhibitor luminespib; a treatment strategy that has been pursued in a confirmatory clinical trial (NCT01854034) for this group of lung adenocarcinomas that currently represent an unmet clinical need in precision oncology.

© 2018 The Japanese Society of Internal Medicine. A 69-year-old man with post-operative recurrence of lung adenocarcinoma was treated with multiple che-motherapies, including epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors. A second biopsy revealed an EGFR T790M mutation. As 10th-line chemotherapy, osimertinib was initiated. After 24 weeks, chest computed tomography (CT) revealed asymptomatic ground-glass opacities in both lobes. After four weeks of osimertinib discontinuation, imaging revealed rapid lung cancer progression. Osimertinib was resumed. After 11 weeks, CT revealed decreased lung nodules with no exacerbation of interstitial lung disease. We describe a patient who experienced transient asymptomatic pulmonary opacities during treatment with osimertinib, which was successfully managed by a “stop-and-go” approach.

Copyright © 2018 by the American Thoracic Society. Lung cancer and chronic obstructive pulmonary disease are leading causes of morbidity and mortality worldwide, and cigarette smoking is a main risk factor for both. The presence of emphysema, an irreversible lung disease, further raises the risk of lung cancer in patients with chronic obstructive pulmonary disease. The mechanisms involved in smoke-induced tumorigenesis and emphysema are not fully understood, attributable to a lack of appropriate animal models. Here, we optimized a model of cigarette smoke (CS)–induced lung cancer and emphysema in A/J mice treated with 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, a potent carcinogen. We investigated whether variations in CS exposure patterns with the same total amount and duration of exposure affect tumorigenesis and/or development of emphysema. Continuous CS exposure for 3 months significantly suppressed 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone–induced development of adenomas and adenocarcinomas; however, emphysema independently developed during this period. Surprisingly, intermittent CS exposure increased the severity of emphysema and resulted in a higher incidence of adenocarcinomas. Furthermore, intermittent CS exposure elicited a marked increase in M2-polarized macrophages within and near the developed tumors. By employing a CS exposure protocol with repeated cycles of cessation and relapse, we provide evidence that intermittent CS exposure enhances tumorigenesis and emphysema progression more than that of continuous CS exposure.

© 2018 American Association for Cancer Research. Multiple epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (EGFR-TKI) have been developed to effectively inhibit EGFR-derived signals in non–small cell lung cancer (NSCLC). In this study, we assessed the efficacy of EGFR-TKIs, including a novel third-generation inhibitor naquotinib (ASP8273), in clinically relevant EGFR mutations, including L858R, exon 19 deletion, L858RþT790M, exon 19 deletionþT790M with or without a C797S mutation, and several exon 20 insertion mutations. Using structural analyses, we also elucidated the mechanism of activation and sensitivity/resistance to EGFR-TKIs in EGFR exon 20 insertion mutations. The efficacy of naquotinib in cells with L858R, exon 19 deletion and exon 19 deletionþT790M was comparable with that of osimertinib. Interestingly, naquotinib was more potent than osimertinib for L858RþT790M. Additionally, naquotinib and osimertinib had comparable efficacy and a wide therapeutic window for cells with EGFR exon 20 insertions. Structural modeling partly elucidated the mechanism of activation and sensitivity/resistance to EGFR-TKIs in two EGFR exon 20 insertion mutants, A767_V769dupASV and Y764_V765insHH. In summary, we have characterized the efficacy of EGFR-TKIs for NSCLC using in vitro and structural analyses and suggested the mechanism of activation and resistance to EGFR-TKIs of EGFR exon 20 insertion mutations. Our findings should guide the selection of appropriate EGFR-TKIs for the treatment of NSCLC with EGFR mutations and help clarify the biology of EGFR exon 20 insertion mutations.

© 2018 Elsevier Inc. We evaluated the real-world efficacy and safety of nivolumab in 142 patients with advanced non–small-cell lung cancer in Japan and identified the clinical characteristics that influence the efficacy. Negative EGFR/ALK mutation status and previous radiotherapy were significantly associated statistically with the treatment response. These findings might aid in the efficient immunotherapeutic management of lung cancer. Background: Nivolumab, an immune checkpoint inhibitor, is now a standard treatment for previously treated advanced non–small-cell lung cancer based on the results from phase III clinical trials. We evaluated the real-world efficacy and safety of nivolumab in a nonselected population and identified the clinical characteristics that influence efficacy. Materials and Methods: A total of 142 patients with advanced non–small-cell lung cancer who were administered nivolumab at Keio University and affiliated hospitals in Japan from January to July 2016 were enrolled. The treatment efficacy and adverse events were retrospectively reviewed, and the clinical characteristics associated with the nivolumab response were evaluated using univariate and stratified analyses and the Cochran-Mantel-Haenszel test. Results: The objective response rate was 17.0% (95% confidence interval [CI], 12.0%-24.0%), the median progression-free survival (PFS) was 58 days (95% CI, 50-67 days), and the proportion of patients with adverse events of any grade was 45.0%. EGFR/ALK mutation status was inversely associated with the treatment response (P <.05), and the difference in PFS for the mutation-positive versus mutation-negative patients was statistically significant (49 vs. 63 days; hazard ratio, 1.9; 95% CI, 1.1-5.2; P =.029). Previous radiotherapy also had a positive association with the treatment response (P =.012). Conclusion: The objective response rate, PFS, and adverse event profiles were comparable to those observed in previous clinical trials. EGFR/ALK mutation-negative status and previous radiotherapy might be key clinical characteristics associated with a positive treatment response. Our findings could aid in the efficient immunotherapeutic management of lung cancer.

© 2018 The Japanese Society of Internal Medicine. Stereotactic radiosurgery (SRS) using the Gamma Knife (GK) is now being increasingly utilized for the treatment of brain metastases. However, there are a few reported cases of SRS-induced brain neoplasms. We herein report the case of a Japanese woman with metastatic non-small cell lung cancer (NSCLC) harboring epidermal growth factor (EGFR)-mutations who was treated four times with a GK for brain metastases. She developed glioblastoma 5.7 years after the initial GK surgery. Radiation-induced secondary neoplasms generally appear after a latency period of several years. Advances in cancer therapy have improved the survival of patients with NSCLC, providing enough time for secondary neoplasms to appear after SRS.

© 2018 Medknow. All rights reserved. Objective: Targeted therapy-induced facial skin toxicities may reduce overall quality of life (QoL) in cancer patients. We investigated whether facial skin toxicities affect QoL and attempted to identify factors related to QoL in patients with advanced/recurrent cancer. Methods: We performed a cross-sectional study in 34 outpatients with advanced/recurrent cancer showing targeted therapy-induced facial skin toxicities in Japan between November 2016 and February 2017. For measurement, we used the Kessler Psychological Distress Scale (K6), Mental Adjustment to Cancer (MAC) Scale, and Dermatology Life Quality Index (DLQI). Data were analyzed using Spearman's rank correlation coefficient. Results: Mean DLQI score in 34 patients was 4.59 (standard deviation ± 4.70), which was interpreted as a small effect on a patient's life. Acneiform rash was the most common skin condition noted, followed by xerosis, pruritus, and erythema. Analysis of DLQI scores revealed that symptoms and feelings was the domain most commonly affected among different domains constituting the DLQI. MAC analysis revealed that the fighting spirit score was the highest among MAC scales. We found that age, K6, and fatalism construct in MAC were significantly correlated with total DLQI scores (age: Spearman's ρ= -0.48, P = 0.004; K6: ρ= 0.58, P < 0.001; fatalism; ρ= -0.39, P = 0.025). Conclusions: This is the first study investigating targeted therapy-induced facial skin toxicities in cancer patients. Our results suggest potential negative effects of facial skin toxicities on overall QoL in patients with advanced/recurrent cancer in middle and early old age.

© 2018 Elsevier Inc. Cancers, including lung cancer, are a leading cause of death worldwide. To overcome this deadly disease, multiple modality inhibitors have been developed. These include cytotoxic agents, molecular targeted small molecules, such as tyrosine kinase inhibitors, and neutralizing antibodies. An aptamer is a short single-stranded nucleic acid molecule that is selected in vitro from a large random sequence library based on its high and specific affinity to a target molecule. Aptamers can be applied to therapeutics of various types of diseases, including cancer, due to their strong and specific neutralizing activities. However, the efficacy of aptamer-based therapy for cancer cells is not well characterized. In this study, we aimed to show that the FGF2 aptamer is effective for the treatment of FGF2 dependent lung cancer cells. We previously developed PC9GR lung cancer cells, whose proliferation is dependent on EGFR and FGF2-FGFR pathways in a cell autonomous manner. Using PC9GR cells, we demonstrate that the addition of the FGF2 aptamer induces more significant inhibition of PC9GR cell proliferation than does the addition of EGFR inhibitor alone. Furthermore, the addition of the FGF2 aptamer more significantly inhibits the downstream signals and induces apoptosis to a higher extent than does the addition of EGFR inhibitor alone. Our results show that the FGF2 aptamer inhibits the growth of FGF2-FGFR pathway-dependent lung cancer cells. The findings provide preclinical evidence that aptamers can be useful for cancer treatment.

© 2018 Elsevier B.V. Objectives: Tumor-associated macrophages (TAMs) are known to promote tumorigenesis but the mechanism(s) remain elusive. We have developed a mouse model of lung cancer that is initiated through an inducible overexpression of fibroblast growth factor 9 (FGF9) in type-2 pneumocytes. Expression of FGF9 in adult lungs resulted in a rapid development of multiple adenocarcinoma-like tumor nodules, and is associated with an intense immunological reaction. The purpose of this study is to characterize the immune response to the FGF9-induced lung adenocarcinoma and to determine the contribution of TAMs to growth and survival of these tumors. Materials and methods: We used flow cytometry, immunostaining, RT-PCR and in vitro culture system on various cell populations isolated from the FGF9-induced adenocarcinoma mouse lungs. Results: Immunostaining demonstrated that the majority of the inflammatory cells recruited to FGF9-induced lung tumors were macrophages. These TAMs were enriched for the alternatively activated (M2) macrophage subtype. TAMs performed a significantly high immune suppressive function on T-cells and displayed high levels of arginase-1 expression and activity. The growth and colony forming potential of tumor cells was induced by co-culture with TAMs. Additionally, TAMs were shown to promote fibroblast proliferation and angiogenesis. TAMs had high expression of Tgf-β Vegf, Fgf2, Fgf10, Fgfr2 and several matrix metalloproteinases; factors that play multiple roles in supporting tumor growth, immune protection, fibroblast activation and angiogenesis. Conclusion: Our results provide evidence that the Fgf9-induced lung adenocarcinoma is associated with recruitment and activation of M2-biased TAMs, which provided multiple means of support to the tumor. This model represents an excellent means to further study the complex interactions between TAMs, their related chemokines, and progression of lung adenocarcinoma, and adds further evidence to support the importance of TAMs in tumorigenesis.

© 2019 National Academy of Sciences. All rights reserved. Next generation sequencing (NGS)-based tumor profiling identified an overwhelming number of uncharacterized somatic mutations, also known as variants of unknown significance (VUS). The therapeutic significance of EGFR mutations outside mutational hotspots, consisting of >50 types, in nonsmall cell lung carcinoma (NSCLC) is largely unknown. In fact, our pan-nation screening of NSCLC without hotspot EGFR mutations (n = 3,779) revealed that the majority (>90%) of cases with rare EGFR mutations, accounting for 5.5% of the cohort subjects, did not receive EGFR-tyrosine kinase inhibitors (TKIs) as a first-line treatment. To tackle this problem, we applied a molecular dynamics simulation-based model to predict the sensitivity of rare EGFR mutants to EGFR-TKIs. The model successfully predicted the diverse in vitro and in vivo sensitivities of exon 20 insertion mutants, including a singleton, to osimertinib, a third-generation EGFR-TKI (R2 = 0.72, P = 0.0037). Additionally, our model showed a higher consistency with experimentally obtained sensitivity data than other prediction approaches, indicating its robustness in analyzing complex cancer mutations. Thus, the in silico prediction model will be a powerful tool in precision medicine for NSCLC patients carrying rare EGFR mutations in the clinical setting. Here, we propose an insight to overcome mutation diversity in lung cancer.

© 2019 American Association for Cancer Research. EGFR-mutated lung cancer is a significant subgroup of non–small cell lung cancer. To inhibit EGFR-mediated signals, multiple EGFR tyrosine kinase inhibitors (EGFR-TKI) have been developed; however, approximately one third of patients with EGFR-mutated lung cancer do not respond to EGFR-TKIs. More effective inhibition of EGFR-mediated signals is therefore necessary. For cancers expressing mutated EGFR, including EGFR T790M, which confers resistance to first- (gefitinib and erlotinib) and second- (afatinib) generation EGFR-TKIs, the synergistic efficacy of afatinib and cetuximab combination therapy has been reported in preclinical and clinical studies; however, the mechanisms underlying this effect remain elusive. In this study, we evaluated the effects of multiple EGFR-TKIs on the EGFR monomer–dimer equilibrium by inducing dimerization-impairing mutations in cells expressing EGFR. Interestingly, we found that afatinib and dacomitinib exhibit a monomer preference: cells expressing dimerization-impaired EGFR mutants exhibited increased sensitivity to afatinib and dacomitinib relative to those with dimerization-competent EGFR mutants. Although EGFR-TKIs themselves induce dimerization of EGFR, the inhibition of dimerization by cetuximab overcame EGFR-TKI–induced dimerization. By shifting the monomer–dimer equilibrium toward monomer dominance using cetuximab, the effectiveness of afatinib and dacomitinib improved significantly. We report a novel and clinically relevant phenomenon, the monomer preference of EGFR-TKIs, which can explain the mechanism underlying the synergism observed in afatinib and cetuximab combination therapy. In addition, we propose the novel concept that monomer–dimer equilibrium is an important factor in determining EGFR-TKI efficacy. These findings provide novel insights into treatment strategies for EGFR-TKI–refractory non–small cell lung cancer.

Alectinib is a highly selective ALK inhibitor and shows promising efficacy in non-small cell lung cancers (NSCLC) harboring the EML4-ALK gene rearrangement. The precise mechanism of acquired resistance to alectinib is not well defined. The purpose of this study was to clarify the mechanism of acquired resistance to alectinib in ALK-translocated lung cancer cells. We established alectinib-resistant cells (H3122-AR) from the H3122 NSCLC cell line, harboring the EML4-ALK gene rearrangement, by long-term exposure to alectinib. The mechanism of acquired resistance to alectinib in H3122-AR cells was evaluated by phospho-receptor tyrosine kinase (phospho-RTK) array screening and Western blotting. No mutation of the ALK-TK domain was found. Phospho-RTK array analysis revealed that the phosphorylation level of EGFR was increased in H3122-AR cells compared with H3122. Expression of TGFalpha, one of the EGFR ligands, was significantly increased and knockdown of TGFalpha restored the sensitivity to alectinib in H3122-AR cells. We found combination therapy targeting ALK and EGFR with alectinib and afatinib showed efficacy both in vitro and in a mouse xenograft model. We propose a preclinical rationale to use the combination therapy with alectinib and afatinib in NSCLC that acquired resistance to alectinib by the activation of EGFR bypass signaling.

EGFR mutated lung cancer accounts for a significant subgroup of non-small-cell lung cancer (NSCLC). Over the last decade, multiple EGFR tyrosine kinase inhibitors (EGFR-TKIs) have been developed to target mutated EGFR. However, there is little information regarding mutation specific potency of EGFR-TKIs against various types of EGFR mutations. The purpose of this study is to establish an in vitro model to determine the "therapeutic window" of EGFR-TKIs against various types of EGFR mutations, including EGFR exon 20 insertion mutations. The potency of 1st (erlotinib), 2nd (afatinib) and 3rd (osimertinib and rociletinib) generation EGFR-TKIs was compared in vitro for human lung cancer cell lines and Ba/F3 cells, which exogenously express mutated or wild type EGFR. An in vitro model of mutation specificity was created by calculating the ratio of IC50 values between mutated and wild type EGFR. The in vitro model identified a wide therapeutic window of afatinib for exon 19 deletions and L858R and of osimertinib and rociletinib for T790M positive mutations. The results obtained with our models matched well with previously reported preclinical and clinical data. Interestingly, for EGFR exon 20 insertion mutations, most of which are known to be resistant to 1st and 2nd generation EGFR-TKIS, osimertinib was potent and presented a wide therapeutic window. To our knowledge, this is the first report that has identified the therapeutic window of osimertinib for EGFR exon 20 insertion mutations. In conclusion, this model will provide a preclinical rationale for proper selection of EGFR-TKIs against clinically-relevant EGFR mutations.

The niche surrounding stem cells regulate their fate during homeostasis and after injury or infection. The 3D organoid assay has been widely used to study stem cells behavior based on its capacity to evaluate self-renewal, differentiation and the effect of various medium supplements, drugs and co-culture with supportive cells. We established an assay to study both lung and trachea stem cells in vitro. We characterized their proliferation and differentiation spectrum at baseline then evaluated the effect of co-culturing with fibroblasts and endothelial cells and/or treating with several biologically relevant substances as possible contributors to their niche. We found that lung epithelial (but not tracheal basal) stem cells require co-culture with stromal cells to undergo clonal proliferation and differentiation. Fibroblasts were more efficient than endothelial cells in offering this support and the pattern of support varied based on the tissue origin of the stromal cells. Treating distal lung epithelial or basal stem cells with FGF2, FGF9, FGF10, LIF as well as ALK5 and ROCK inhibitors increased their colony formation efficiency and resulted in variable effects on colonies number, size and differentiation spectrum. This model and findings pave the way for better understanding of lung stem cell niche components and factors that can manipulate lung stem cell behavior.