Cancer cell microenvironments, including host cells, can critically affect cancer cell behaviors, including drug sensitivity. Although crizotinib, a dual tyrosine kinase inhibitor (TKI) of ALK and ...Met, shows dramatic effect against EML4-ALK lung cancer cells, these cells can acquire resistance to crizotinib by several mechanisms, including ALK amplification and gatekeeper mutation. We determined whether microenvironmental factors trigger ALK inhibitor resistance in EML4-ALK lung cancer cells.
We tested the effects of ligands produced by endothelial cells and fibroblasts, and the cells themselves, on the susceptibility of EML4-ALK lung cancer cell lines to crizotinib and TAE684, a selective ALK inhibitor active against cells with ALK amplification and gatekeeper mutations, both in vitro and in vivo.
EML4-ALK lung cancer cells were highly sensitive to ALK inhibitors. EGF receptor (EGFR) ligands, such as EGF, TGF-α, and HB-EGF, activated EGFR and triggered resistance to crizotinib and TAE684 by transducing bypass survival signaling through Erk1/2 and Akt. Hepatocyte growth factor (HGF) activated Met/Gab1 and triggered resistance to TAE684, but not crizotinib, which inhibits Met. Endothelial cells and fibroblasts, which produce the EGFR ligands and HGF, respectively, decreased the sensitivity of EML4-ALK lung cancer cells to crizotinib and TAE684, respectively. EGFR-TKIs resensitized these cells to crizotinib and Met-TKI to TAE684 even in the presence of EGFR ligands and HGF, respectively.
Paracrine receptor activation by ligands from the microenvironment may trigger resistance to ALK inhibitors in EML4-ALK lung cancer cells, suggesting that receptor ligands from microenvironment may be additional targets during treatment with ALK inhibitors.
Rearrangement of the neurotrophic tropomyosin receptor kinase 1 (
) gene, which encodes tyrosine receptor kinase A (TRK-A), occurs in various cancers, including colon cancer. Although entrectinib is ...effective in the treatment of central nervous system (CNS) metastases that express
fusion proteins, acquired resistance inevitably results in recurrence. The CNS is a sanctuary for targeted drugs; however, the mechanism by which CNS metastases become entrectinib-resistant remains elusive and must be clarified to develop better therapeutics.
The entrectinib-resistant cell line KM12SM-ER was developed by continuous treatment with entrectinib in the brain metastasis-mimicking model inoculated with the entrectinib-sensitive human colon cancer cell line KM12SM, which harbors the
gene fusion. The mechanism of entrectinib resistance in KM12SM-ER cells was examined by next-generation sequencing. Compounds that overcame entrectinib resistance were screened from a library of 122 kinase inhibitors.
KM12SM-ER cells, which showed moderate resistance to entrectinib
, had acquired the G667C mutation in
The kinase inhibitor foretinib inhibited TRK-A phosphorylation and the viability of KM12SM-ER cells bearing the
-G667C mutation
Moreover, foretinib markedly inhibited the progression of entrectinib-refractory KM12SM-ER-derived liver metastases and brain tumors in animal models, predominantly through inhibition of TRK-A phosphorylation.
These results suggest that foretinib may be effective in overcoming entrectinib resistance associated with the
-G667C mutation in
fusion-positive tumors in various organs, including the brain, and provide a rationale for clinical trials of foretinib in cancer patients with entrectinib-resistant tumors harboring the
-G667C mutation, including patients with brain metastases.
.
Two large-scale cross-hole pumping tests were conducted at depths of 191-226 m and 662-706 m in deep boreholes at the Mizunami Underground Research Laboratory (MIU) construction site in central ...Japan. During these two tests, induced groundwater responses were monitored at many observation intervals at various depths in different boreholes at the site. We analyze the two cross-hole pumping tests using transient hydraulic tomography (THT) based on an efficient sequential successive linear estimator to compute the hydraulic conductivity (K) and specific storage (S(s)) tomograms, as well as their uncertainties in three dimensions. The equivalent K and S(s) estimates obtained using asymptotic analysis treating the medium to be homogeneous served as the mean parameter estimates for the 3-D stochastic inverse modeling effort. Results show several, distinct, high K and low S(s) zones that are continuous over hundreds of meters, which appear to delineate fault zones and their connectivity. The THT analysis of the tests also identified a low K zone which corresponds with a known fault zone trending NNW and has been found to compartmentalize groundwater flow at the site. These results corroborate well with observed water level records, available fault information, and coseismic groundwater level responses during several large earthquakes. The successful application of THT to cross-hole pumping tests conducted in fractured granite at this site suggests that THT is a promising approach to delineate large-scale K and S(s) heterogeneities, fracture connectivity, and to quantify uncertainty of the estimated fields.
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Anaplastic thyroid carcinoma (ATC) is a rare but aggressive undifferentiated tumor that frequently metastasizes to the brain. The multiple kinase inhibitor lenvatinib and sorafenib have been approved ...to treat unresectable differentiated thyroid cancer, and lenvatinib has been approved in Japan to treat ATC. This study compared the effects of lenvatinib and sorafenib in mouse models of central nervous system metastases of ATC. Immunodeficient mice were inoculated with ATC cells, and the effects of lenvatinib and sorafenib were evaluated in subcutaneous- and brain metastasis-mimicking models. Drug distribution was evaluated by imaging tandem mass spectrometry (ITMS). Neither lenvatinib nor sorafenib affected the viability of ATC cell lines, whereas both inhibited VEGF secretion by ATC cells. In the subcutaneous tumor model, both lenvatinib and sorafenib inhibited growth and were associated with reduced tumor microvessel density. In the brain metastasis-mimicking model, lenvatinib, but not sorafenib, inhibited the growth of ATC cells and reduced microvessel density in brain lesions. ITMS showed that lenvatinib was well-distributed in both subcutaneous and brain lesions, whereas the distribution of sorafenib was lower in brain than in subcutaneous lesions. These results demonstrate that lenvatinib is well-distributed in mouse models of ATC, and inhibited the growth of ATC brain lesions predominantly by inhibiting angiogenesis, suggesting that lenvatinib is highly potent against ATC brain metastases.
A variety of chemicals have been used in a wide range of indoor materials, such as wallpaper and furniture, and some of them are released into the indoor air. The level of consumption as well as the ...diversity of these chemicals has been increasing. The particle size of the materials in the air is known to affect the depth of human exposure, e.g., particles >10 μm can only reach the nasal cavity, whereas particles 2.5–10 μm can reach the respiratory tract and particles <2.5 μm can reach the bottom of the lungs. However, information on the concentrations and form of these chemicals in indoor air is very limited. In this study, we measured 54 compounds, including plasticizers (phthalates, adipates, and others) and organophosphorus flame retardants, in indoor air samples from the living rooms of 21 dwellings in 11 prefectures across Japan. For sampling, we used a four-stage air sampler (multi-nozzle cascade impactor) equipped with three quartz fiber filters to capture chemical particulates in three size ranges (<2.5, 2.5–10, and >10 μm) and a C
18
solid-phase extraction disk to capture chemicals that exist in a gas phase in indoor air. Each of the chemicals in the three particulate phases and single gas phase was extracted by acetone and measured separately using GC/MS. Of the 54 compounds tested, 37 were detected in the indoor air samples. The highest concentration observed was that of 2-ethyl-1-hexanol (5.1 μg/m
3
), which was detected in samples from all 21 houses. The 37 compounds were captured in the four fractions at different rates roughly based on their molecular sizes. Compounds with a smaller molecular size were commonly detected as a gas phase, whereas compounds with a larger molecular size were detected as one or more of the three particulate phases in the indoor air samples. Among the three particulate phases, many of the compounds were detected from the filter capturing the smallest (<2.5 μm) particles. Therefore, these results suggest that the chemicals measured in this study might penetrate deeply into the lungs as many of them tend to exist as a gas and/or as particles smaller than 2.5 μm.
Malignant pleural mesothelioma (MPM) is characterized by dissemination and aggressive growth in the thoracic cavity. Podoplanin (PDPN) is an established diagnostic marker for MPM, but the function of ...PDPN in MPM is not fully understood. The purpose of this study was to determine the pathogenetic function of PDPN in MPM. Forty‐seven of 52 tumors (90%) from Japanese patients with MPM and 3/6 (50%) MPM cell lines tested positive for PDPN. Knocking down PDPN in PDPN‐high expressing MPM cells resulted in decreased cell motility. In contrast, overexpression of PDPN in PDPN‐low expressing MPM cells enhanced cell motility. PDPN stimulated motility was mediated by activation of the RhoA/ROCK pathway. Moreover, knocking down PDPN with short hairpin (sh) RNA in PDPN‐high expressing MPM cells resulted in decreased development of a thoracic tumor in mice with severe combined immune deficiency (SCID). In sharp contrast, transfection of PDPN in PDPN‐low expressing MPM cells resulted in an increase in the number of Ki‐67‐positive proliferating tumor cells and it promoted progression of a thoracic tumor in SCID mice. Interestingly, PDPN promoted focus formation in vitro, and a low level of E‐cadherin expression and YAP1 activation was observed in PDPN‐high MPM tumors. These findings indicate that PDPN is a diagnostic marker as well as a pathogenetic regulator that promotes MPM progression by increasing cell motility and inducing focus formation. Therefore, PDPN might be a pathogenetic determinant of MPM dissemination and aggressive growth and may thus be an ideal therapeutic target.
Podoplanin (PDPN) is an established diagnostic marker for malignant pleural mesothelioma (MPM), but the function of PDPN in MPM is not fully understood. In the present study, we demonstrated that PDPN plays a major role in the progression of MPM by stimulating cell motility via RhoA/ROCK pathway activation and by blocking contact inhibition associated with decreased E‐cadherin expression and YAP1 activation.Collectively, our findings indicate that PDPN is an ideal target for treatment of patients with MPM.
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The aryl hydrocarbon receptor (AhR) is a ligand-dependent transcription factor that regulates genes involved in xenobiotic metabolism, cellular proliferation and differentiation. In this study, we ...have developed a highly sensitive AhR-mediated reporter cell line, DR-EcoScreen cells, which are mouse hepatoma Hepa1c1c7 cells stably transfected with a reporter plasmid containing seven copies of dioxin-responsive element. Using these DR-EcoScreen cells, we performed the reporter gene assay and characterized the AhR agonistic activities of 200 pesticides (29 organochlorines, 11 diphenyl ethers, 56 organophosphorus pesticides, 12 pyrethroids, 22 carbamates, 12 acid amides, 7 triazines, 6 ureas, and 45 others). Eleven of the 200 pesticides (acifluorfen-methyl, bifenox, chlorpyrifos, isoxathion, quinalphos, chlorpropham, diethofencarb, propanil, diuron, linuron, and prochloraz) showed AhR-mediated transcriptional activity. In particular, three herbicides (propanil, diuron, and linuron) have a common chemical structure and showed more potent agonistic activity than other pesticides. To investigate the
in vivo effects, we examined the gene expression of AhR-inducible cytochrome P450 1As (
CYP1As) in the liver of female C57BL/6 mice intraperitoneally injected with these three herbicides (⩽300
mg
kg
−1) by quantitative RT-PCR, resulting in induction of significant high levels of
CYP1A1 and
CYP1A2 mRNAs. This indicates that propanil, diuron and linuron possess AhR-mediated transactivation effect
in vivo as well as
in vitro. Through the present study, we demonstrated that DR-EcoScreen cells are useful for sensitive, rapid and simple identification of AhR agonists among a large number of environmental chemicals.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Patients with epidermal growth factor receptor (EGFR)‐mutated non‐small cell lung cancer (NSCLC) harboring BIM deletion polymorphism (BIM deletion) have poor responses to EGFR TKI. Mechanistically, ...the BIM deletion induces preferential splicing of the non‐functional exon 3‐containing isoform over the functional exon 4‐containing isoform, impairing TKI‐induced, BIM‐dependent apoptosis. Histone deacetylase inhibitor, vorinostat, resensitizes BIM deletion‐containing NSCLC cells to EGFR‐TKI. In the present study, we determined the safety of vorinostat‐gefitinib combination and evaluated pharmacodynamic biomarkers of vorinostat activity. Patients with EGFR‐mutated NSCLC with the BIM deletion, pretreated with EGFR‐TKI and chemotherapy, were recruited. Vorinostat (200, 300, 400 mg) was given daily on days 1‐7, and gefitinib 250 mg was given daily on days 1‐14. Vorinostat doses were escalated based on a conventional 3 + 3 design. Pharmacodynamic markers were measured using PBMC collected at baseline and 4 hours after vorinostat dose on day 2 in cycle 1. No dose‐limiting toxicities (DLT) were observed in 12 patients. We determined 400 mg vorinostat as the recommended phase II dose (RP2D). Median progression‐free survival was 5.2 months (95% CI: 1.4‐15.7). Disease control rate at 6 weeks was 83.3% (10/12). Vorinostat preferentially induced BIM mRNA‐containing exon 4 over mRNA‐containing exon 3, acetylated histone H3 protein, and proapoptotic BIMEL protein in 11/11, 10/11, and 5/11 patients, respectively. These data indicate that RP2D was 400 mg vorinostat combined with gefitinib in BIM deletion/EGFR mutation double‐positive NSCLC. BIM mRNA exon 3/exon 4 ratio in PBMC may be a useful pharmacodynamic marker for treatment.
Vorinostat, in combination with gefitinib, induced acetylated histone H3 protein expression, as well as a decrease in the BIM mRNA exon 3/exon 4 ratio in PBMC from BIM deletion polymorphism/EGFR mutation double‐positive NSCLC patients. These results provide proof of concept that the combined therapy can mitigate the functional effects of BIM deletion polymorphism.
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Small‐cell lung cancer (SCLC) grows rapidly and metastasizes to multiple organs. We examined the antimetastatic effects of the humanized anti‐ganglioside GM2 (GM2) antibodies, BIW‐8962 and KM8927, ...compared with the chimeric antibody KM966, in a SCID mouse model of multiple organ metastases induced by GM2‐expressing SCLC cells. BIW‐8962 and KM8927 induced higher antibody‐dependent cellular cytotoxicity and complement‐dependent cytotoxicity than KM966 against the GM2‐expressing SCLC cell line SBC‐3 in vitro. These humanized antibodies inhibited the production of multiple organ metastases, increased the number of apoptotic cells, and prolonged the survival of the SCID mice. Histological analyses using clinical specimens showed that SCLC cells expressed GM2. These findings suggest that humanized anti‐GM2 antibodies could be therapeutically useful for controlling multiple organ metastases of GM2‐expressing SCLC. (Cancer Sci 2011; 102: 2157–2163)
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Highlights ► We examine hormonal activities of 100 hydroxylated polychlorinated biphenyls. ► We use four assays of estrogen alpha, beta, androgen, and glucocorticoid receptor. ► We find estrogenic ...and/or antiandrogenic activities of many of the test compounds. ► 30 compounds show antagonist activities via glucocorticoid receptor. ► Substituting positions of hydroxyl group and chlorines relate to hormonal activities.
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