論文

A highly potent and selective metabotropic glutamate receptor (mGluR) 1 antagonist, 4-[1-(2-fluoropyridin-3-yl)-5-methyl-1H-1,2, 3-triazol-4-yl]-N-isopropyl-N-methyl-3,6-dihydropyridine-1(2H)carboxamide( FTIDC), is described. FTIDC inhibits, with equal potency, L-glutamate-induced intracellular Ca2+ mobilization in Chinese hamster ovary cells expressing human, rat, or mouse mGluR1a. The IC50 value of FTIDC is 5.8 nM for human mGluR1a and 6200 nM for human mGluR5. The maximal response in agonist concentration-response curves was reduced in the presence of higher concentrations of FTIDC, suggesting the inhibition in a noncompetitive manner. FTIDC at 10 mu M showed no agonistic, antagonistic, or positive allosteric modulatory activity toward mGluR2, mGluR4, mGluR6, mGluR7, or mGluR8. FTIDC did not displace [H-3]L-quisqualate binding to human mGluR1a, indicating FTIDC is an allosteric antagonist. Studies using chimeric and mutant receptors of mGluR1 showed that transmembrane (TM) domains 4 to 7, especially Phe801 in TM6 and Thr815 in TM7, play pivotal roles in the antagonism of FTIDC. FTIDC inhibited the constitutive activity of mGluR1a, suggesting that FTIDC acts as an inverse agonist of mGluR1a. Intraperitoneally administered FTIDC inhibited face-washing behavior elicited by a group I mGluR agonist, (S)-3,5-dihydroxyphenylglycine in mice at doses that did not produce motor impairment. Oral administration of FTIDC also inhibited the face-washing behavior. FTIDC is a highly potent and selective allosteric mGluR1 antagonist and a compound having oral activity without species differences in its antagonistic activity on recombinant human, mouse, and rat mGluR1. FTIDC could therefore be a valuable tool for elucidating the functions of mGluR1 not only in rodents but also in humans.

© 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 (R 2 = 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.

© 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. 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.

Cancer cells are surrounded by the extracellular fluid, matrix, and stroma cells. Little is known about how extracellular components such as growth factor ligands affect the biology of lung cancer cells. The objective of this study was to determine whether extracellular fibroblast growth factors (FGFs) can affect the biology of lung cancer cells and to understand how extracellular FGFs affect the biology of lung cancer cells, including non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) cells. Out of the 23 reported FGFs, we focused on FGF2, FGF9 and FGF10. We examined the effect of FGFs on proliferation, treatment sensitivity, and apoptosis of NSCLC (PC9) and SCLC (H69, H82 and H146) cells in vitro. To determine which FGF was the most clinically relevant, we also examined FGF2 and FGF9 concentrations in the serum of patients with lung cancer. We found that extracellular FGFs can affect proliferation, treatment sensitivity, and apoptosis of lung cancer cells in a cell-specific manner. Our results indicate that extracellular FGFs affect the biology of lung cancer cells through multiple functions.

Epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (EGFR-TKIs) are widely used for the treatment of non-small cell lung cancers (NSCLCs) harboring EGFR-activating mutations. However, lung cancer cells inevitably acquire resistance to these EGFR-TKIs. The majority of patients whose lung cancer acquires resistance to EGFR-TKIs are subjected to treatment using cytotoxic agents. The present study aimed to determine if lung cancer cells acquiring resistance to EGFR-TKIs also develop altered sensitivity to cytotoxic agents. It was revealed that lung cancer cells that had developed resistance to EGFR-TKIs had increased sensitivity to gemcitabine and vinorelbine compared with EGFR-TKI naive cells. The expression levels of ATP-binding cassette (ABC) transporter genes, including ABCC3, ABCC5 and ABCG2, were observed to be commonly repressed in EGFR-TKI-resistant cells. In addition, two cases were identified in which gemcitabine and vinorelbine exerted marked responses to lung cancers that had acquired resistance to EGFR-TKIs, even with late-line treatment. Therefore, it was proposed that gemcitabine and vinorelbine may be effective agents for patients with lung cancer previously treated with EGFR-TKIs.

Activation of the EGFR pathway is one of the mechanisms inducing acquired resistance to anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors (TKI) such as crizotinib and alectinib. Ceritinib is a highly selective ALK inhibitor and shows promising efficacy in non-small cell lung cancers (NSCLC) harboring the ALK gene rearrangement. However, the precise mechanism underlying acquired resistance to ceritinib is not well-defined. This study set out to clarify the mechanism in ALK-translocated lung cancer and to find the preclinical rationale overcoming EGFR pathway-induced acquired resistance to ALK-TKIs. To this end, ceritinib-resistant cells (H3122-CER) were established from the H3122 NSCLC cell line harboring the ALK gene rearrangement via long-term exposure to ceritinib. H3122-CER cells acquired resistance to ceritinib through EGFR bypass pathway activation. Furthermore, H3122 cells that became resistant to ceritinib or alectinib through EGFR pathway activation showed cross-resistance to other ALK-TKIs. Ceritinib and afatinib combination treatment partially restored the sensitivity to ceritinib. (C) 2016 AACR.

PTPRH is a receptor-type protein tyrosine phosphatase thought to be a potential regulator of tumorigenesis. The aim of the present study was to clarify the significance of PTPRH expression and its regulation by DNA methylation in non-small cell lung cancer (NSCLC), especially in lung adenocarcinoma (LADC). PTPRH mRNA expression was examined in 89 NSCLC and corresponding non-cancerous tissues. The correlation between DNA methylation and PTPRH gene expression was investigated in another cohort that consisted of 145 patients with LADC, a major NSCLC subtype. Gene regulation by DNA methylation was assessed using a DNA methylation inhibitor. PTPRH mRNA expression was significantly upregulated in NSCLC. PTPRH DNA methylation was reduced in LADC samples and inversely correlated with mRNA expression. 5-Aza-2'-deoxycytidine treatment of lung cancer cell lines with low PTPRH expression, restored mRNA PTPRH expression levels. Furthermore, low PTPRH methylation was associated with shorter recurrence-free survival (P=1.64x10(-4)) and overall survival (P=5.54x10(-5)). Multivariate analysis revealed that PTPRH DNA methylation was an independent prognostic factor (P=6.88x10(-3)). It was confirmed that PTPRH is overexpressed in NSCLC. Furthermore, we determined that PTPRH is epigenetically regulated by DNA hypomethylation, with prognostic implications for LADC.

Background Several sensitive assays, including the PCR-invader method (structure-specific 5' nuclease-based method), have been used to detect EGFR mutations in non-small-cell lung cancer (NSCLC). However, validation has not been reported. We assessed the detection rate of EGFR mutation by the PCR-invader method and direct sequencing using same clinical specimens. Patients and methods EGFR mutations were analyzed with the PCR-invader method and compared with direct sequencing using paraffin tissues and pleural and pericardial effusions from NSCLC patients. The relationships between the treatment responses and mutations were evaluated retrospectively. Results Fifty-four samples from 42 NSCLC patients were studied. EGFR mutations were identified in 52% of the patients and 52% of the samples with the PCR-invader method, but only in 43% of the patients and in 35% of the samples by direct sequencing. In the samples obtained from the same patients at different sites and different times, EGFR mutations were coincident in nine out of ten patients by the PCR-invader method but in six out of ten patients by direct sequencing. Seventeen patients with EGFR mutations were treated with gefitinib; the response rate (RR) and disease control rate (DCR) were 41 and 94%, and median treatment duration was more than 6 months. Seven EGFR mutation-negative patients were treated with gefitinib; the RR and DCR were 0 and 14%, and median treatment duration was 1 month. Conclusion The PCR-invader method was useful for detecting EGFR mutations in clinical lung cancer specimens and is more sensitive than direct sequencing.

Background: Preliminary studies have identified cancer stem cells (CSCs) in various cancers and there are several ongoing clinical studies targeting these cells. CD44 (standard or variant isoforms) and/or aldehyde dehydrogenase (ALDH) expression is the most commonly used markers for the identification of CSCs. The goal of the current study was to examine the ability of CD44v, either alone or in combination with ALDH, to identify CSCs within human lung cancer cells lines. Methods: We examined several lung adenocarcinoma cell lines for the ability of CD44v and/or ALDH expression to enrich for cells with CSC characteristics such as in vitro differential proliferation rate, chemotherapeutic-resistance, tumorsphere formation, and in vivo tumorigenicity. We also compared their in vivo secondary tumor formation, and histological characteristics of their xenograft tumors, and examined their expression of PD-L1, EGFR, xCT, and reactive oxygen species (ROS). Results: Both CD44v(high)/ALDH(high) and CD44v(high)/ALDH(low) cells were enriched in cells with CSC characteristics, with the CD44v(high)/ALDH(low) cells being more proliferative and more resistant to chemotherapeutics, whereas CD44v(high)/ALDH(high) cells were more efficient in forming tumorspheres in vitro, in making primary xenograft tumors, and in propagating secondary tumors in vivo. Applying stricter sorting gates to select for cells with the highest CD44v/ALDH expression caused the CD44v(high)/ALDH(low) cells to lose their high proliferation rates and chemotherapeutic resistance ability, but enriched for the tumorsphere-forming cells among the CD44v(high)/ALDH(high) and CD44v(high)/ALDH(low) cells. CD44v(high) expression was associated with PD-L1 and xCT expression in both H1650 and HCC827 cells. This association was not modified by ALDH expression in the H1650 cell line. However, in the HCC827 cell line, ALDH expression was negatively associated with PD-L1 and positively associated with xCT expression. Conclusion: Lung adenocarcinoma cells with high CD44v expression are enriched for CSCs. Addition of ALDH as an enrichment marker bestowed some CSCs characteristics to CD44v(high)/ALDH(low) cells and others to CD44v(high)/ALDH(high) cells. We propose that lung adenocarcinoma contains different CSCs, each of them endowed with different CSC characteristics.

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.

EGFR mutation-positive patients with non–small cell lung cancer (NSCLC) respond well to treatment with EGFR–tyrosine kinase inhibitors (EGFR–TKI); however, treatment with EGFR–TKIs is not curative, owing to the presence of residual cancer cells with intrinsic or acquired resistance to this class of drugs. Additional treatment targets that may enhance the efficacy of EGFR–TKIs remain elusive. Using a CRISPR/Cas9-based screen, we identified the leucine-rich repeat scaffold protein SHOC2 as a key modulator of sensitivity to EGFR–TKI treatment. On the basis of in vitro assays, we demonstrated that SHOC2 expression levels strongly correlate with the sensitivity to EGFR–TKIs and that SHOC2 affects the sensitivity to EGFR–TKIs in NSCLC cells via SHOC2/MRAS/PP1c and SHOC2/SCRIB signaling. The potential SHOC2 inhibitor celastrol phenocopied SHOC2 depletion. In addition, we confirmed that SHOC2 expression levels were important for the sensitivity to EGFR–TKIs in vivo. Furthermore, IHC showed the accumulation of cancer cells that express high levels of SHOC2 in lung cancer tissues obtained from patients with NSCLC who experienced acquired resistance to EGFR–TKIs. These data indicate that SHOC2 may be a therapeutic target for patients with NSCLC or a biomarker to predict sensitivity to EGFR–TKI therapy in EGFR mutation-positive patients with NSCLC. Our findings may help improve treatment strategies for patients with NSCLC harboring EGFR mutations. Implications: This study showed that SHOC2 works as a modulator of sensitivity to EGFR–TKIs and the expression levels of SHOC2 can be used as a biomarker for sensitivity to EGFR–TKIs.

Transdifferentiation of lung adenocarcinoma to small cell lung cancer (SCLC) has been reported in a subset of lung cancer cases that bear EGFR mutations. Several studies have reported the prerequisite role of TP53 and RB1 alterations in transdifferentiation. However, the mechanism underlying transdifferentiation remains understudied, and definitive additional events, the third hit, for transdifferentiation have not yet been identified. In addition, no prospective experiments provide direct evidence for transdifferentiation. In this study, we show that FGF9 upregulation plays an essential role in transdifferentiation. An integrative omics analysis of paired tumor samples from a patient with transdifferentiated SCLC exhibited robust upregulation of FGF9. Furthermore, FGF9 upregulation was confirmed at the protein level in four of six (66.7%) paired samples. FGF9 induction transformed mouse lung adenocarcinoma-derived cells to SCLC-like tumors in vivo through cell autonomous activation of the FGFR pathway. In vivo treatment of transdifferentiated SCLC-like tumors with the pan-FGFR inhibitor AZD4547 inhibited growth. In addition, FGF9 induced neuroendocrine differentiation, a pathologic characteristic of SCLC, in established human lung adenocarcinoma cells. Thus, the findings provide direct evidence for FGF9-mediated SCLC transdifferentiation and propose the FGF9–FGFR axis as a therapeutic target for transdifferentiated SCLC.

Objective: To elucidate tumor mutation profiles associated with outcomes of uterine cervical cancer (UCC) patients treated with definitive radiotherapy. Methods: Ninety-eight patients with newly diagnosed and pathologically confirmed UCC (82 squamous cell carcinomas, 12 adenocarcinomas, and four adenosquamous carcinomas) who were treated with definitive radiotherapy were analyzed. DNA was extracted from pre-treatment tumor biopsy specimens. The exons of 409 cancer-related genes were sequenced using a next-generation sequencer. Genetic mutations were identified and analyzed for correlations with clinical outcome. Results: Recurrent mutations were observed in PIK3CA (35.7%), ARID1A (25.5%), NOTCH1 (19.4%), FGFR3 (16.3%), FBXW7 (19.4%), TP53 (13.3%), EP300 (12.2%), and FGFR4 (10.2%). The prevalence of mutations in FGFR family genes (i.e., FGFR1–4) was almost as high (24.5%) as that in PIK3CA and ARID1A, both of which are well-studied drivers of UCC. Fifty-five percent (21 of 38) of the identified FGFR mutations were located in the FGFR protein tyrosine kinase domain. Five-year progression-free survival (PFS) rates for FGFR mutation-positive patients (n = 24) were significantly worse than those for FGFR mutation-negative patients (n = 74) (43.9% vs. 68.5%, respectively; P = 0.010). Multivariate analysis identified FGFR mutations as significant predictors of worse 5 year PFS (P = 0.005), independent of clinicopathological variables. Conclusions: FGFR mutations are associated with worse PFS in UCC patients treated with definitive radiotherapy. These results warrant further validation in prospective studies.

RNA splicing dysregulation has emerged as a hallmark of cancer and a promising therapeutic target; however, its full landscape in human solid cancer remains poorly characterized. To address this, we perform alternative splicing analyses using RNA-sequencing data from 751 lung adenocarcinoma samples from our cohort integrated with 519 samples from The Cancer Genome Atlas. Visualization of splicing patterns using t-distributed stochastic neighbor embedding reveals substantial inter-tumor heterogeneity driven by distinct molecular subtypes and histological differentiation. We identify a unique molecular subtype associated with inactivating mutations in CMTR2, which encodes Cap-specific mRNA (nucleoside-2’-O-)-methyltransferase 2. CMTR2 mutations are observed in 3.8% of cases and are predominantly truncating mutations, which form an isolated cluster within the splicing landscape. Intrinsic and CRISPR-Cas9-engineered CMTR2 mutations disrupt alternative splicing and sensitize cancer cells to sulfonamide-based RNA splicing modulators and immune checkpoint blockade therapy. Retrospective patient data confirm the increased sensitivity of CMTR2-deficient tumors to immune checkpoint blockade therapy. These findings uncover a previously unrecognized RNA splicing deficiency in human cancers and define a molecular subtype of lung adenocarcinoma driven by RNA splicing dysregulation, suggesting targets for therapeutic intervention in lung cancer.

Background: The prognosis of lung cancer complicated by chronic obstructive pulmonary disease is poor, and effective prophylactic agents have not been established. Given that inflammation is a shared pathogenic mechanism of both diseases, we aimed to evaluate the efficacy of roflumilast, a novel anti-inflammatory drug, in preventing emphysema and lung cancer using a smoking-induced lung cancer mouse model. Methods: Male A/J mice were exposed to 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, a potent carcinogen, and intermittent mainstream cigarette smoke for 20 weeks. Roflumilast or vehicle was administered via intragastric gavage once daily. Lung tissues were assessed for tumor nodules and emphysema, and bronchoalveolar lavage fluid was collected for cell counting. Emphysema severity and concentrations of inflammatory cytokines (IL-6, IL-1β, and TNF-α) were assessed. RAW 264.7 macrophage cells were used to assess cellular responses to cigarette smoke extract. Results: Roflumilast attenuated the increase in total cells and macrophages in bronchoalveolar lavage fluid induced by intermittent smoking exposure and significantly suppressed smoking-induced expressions of IL-6, IL-1β, and TNF-α. Roflumilast also reduced emphysematous changes and the number of lung tumors. In vitro, roflumilast attenuated cigarette smoke extract-induced expression of IL-6, IL-1β, and TNF-α in RAW 264.7 cells. Conclusions: This study highlights the potential use of roflumilast as a chemopreventive agent for patients with chronic obstructive pulmonary disease who are at risk of lung cancer and underscores its relevance for future clinical application and research on phosphodiesterase-4 inhibitors.

Currently tested allosteric modulators for metabotropic glutamate receptor 1 (mGluR1) are known to regulate the activity of mGluR1 mainly through transmembrane (TM) domain 6 and/or 7. We identified a novel interaction site, N760 in TM5, which negatively regulates activation of mGluR1 with a newly discovered selective mGluR1 antagonist, 3-cyclohexyl-5-fluoro-6-methyl-7-(2-morpholinA-ylethoxy)-4H-chromen-4-one (CFMMC). CFMMC inhibited L-glutamate-induced intracellular Ca(2+) mobilization ([Ca(2+)](i)) in Chinese hamster ovary (CHO) cells expressing recombinant human mGluR1 a with IC(50) value of 50 nM, whereas it did not inhibit [Ca(2+)](i) in CHO cells expressing human mGluR5a [IC(50): >10 mu M). To identify the amino acid residues critical for antagonism of CFMMC, we constructed various point mutants of human mGluR1 and evaluated them in [Ca(2+)](i) assays. The inhibitory effects of CFMMC were significantly affected in point mutations of either I725 in TM4 or N760 in TM5, as well as mutations of W798, F801 and Y805 in TM6 or T815 in TM7. Further studies revealed that antagonistic activities of not only CFMMC but also other, structurally unrelated, mGluR1 antagonists such as 6-amino-N-cyclohexyl-N,3-dimethylthiazolo[3,2-a]benzimidazole-2-carboxamide (YM-298198) and Compound 1 were reduced in N760 mutated mGluR1a. These results indicate that some mGluR1 allosteric antagonists require N760 in TM5 to demonstrate negative modulation of mGluR1 in addition to the reported amino acid residues in TM6 and TM7. (C) 2009 Elsevier Ltd. All rights reserved.

© 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.

Objectives: We previously reported low expression of miR-375 in squamous-cell carcinoma (SCC) and high expression in adenocarcinoma (AC) of the lung. miR-375's target genes and its function in non-small-cell lung cancer (NSCLC) have not been elucidated. Therefore, the present study was designed to identify the targets of miR-375 and to characterize its function in NSCLC. Materials and methods: Candidate targets of miR-375 were determined using a prediction database and previous data on differential gene expression between SCC and AC. We evaluated miR-375 and target-gene expression levels in 12 NSCLC cell lines. The effect of miR-375 overexpression and knockdown was evaluated in NSCLC cell lines by transfecting them with an miR-375 precursor or inhibitor. A luciferase-reporter assay was performed to confirm a direct interaction between miR-375 and its target gene. Further, a wound-healing assay was performed to evaluate the effect of miR-375 overexpression on the migration of SK-MES-1 cells. Finally, to assess the clinical relevance, 63 clinical NSCLC samples were analyzed. Results: Claudin-1 (CLDN1) has 4 putative miR-375 target sites in its 3'-untranslated region, and this gene was determined to be a target of miR-375. CLDN1 messenger RNA and protein expression were attenuated by overexpression of miR-375 and increased by knockdown of miR-375 in NSCLC cell lines. In a luciferase-reporter assay, miR-375 overexpression resulted in a 3-fold repression of luciferase activity (P<0.001). Cell migration was promoted by miR-375 overexpression, suggesting a high potential for invasion and metastasis in NSCLC expressing high levels of miR-375. In clinical NSCLC samples, there was a negative correlation between miR-375 and CLDN1 expression (r=-0.35, P=0.005). In addition, high miR-375 expression was correlated with a shorter survival time among the clinical samples (P=0.043). Conclusion: CLDN1 is a novel target of miR-375, and high miR-375 expression shortens survival in NSCLC. (C) 2014 Elsevier Ireland Ltd. All rights reserved.