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Leucine-rich repeat kinase 2 (LRRK2), a large GTP-regulated serine/threonine kinase, is well-known for its mutations causing late-onset Parkinson's disease. However, the role of LRRK2 in glioblastoma (GBM) carcinogenesis has not yet been fully elucidated. Here, we discovered that LRRK2 was overexpressed in 40% of GBM patients, according to tissue microarray analysis, and high LRRK2 expression correlated with poor prognosis in GBM patients. LRRK2 and stemness factors were highly expressed in various patient-derived GBM stem cells, which are responsible for GBM initiation. Canonical serum-induced differentiation decreased the expression of both LRRK2 and stemness factors. Given that LRRK2 is a key regulator of glioma stem cell (GSC) stemness, we developed DNK72, a novel LRRK2 kinase inhibitor that penetrates the blood-brain barrier. DNK72 binds to the phosphorylation sites of active LRRK2 and dramatically reduced cell proliferation and stemness factors expression in in vitro studies. Orthotopic patient-derived xenograft mouse models demonstrated that LRRK2 inhibition with DNK72 effectively reduced tumor growth and increased survival time. We propose that LRRK2 plays a significant role in regulating the stemness of GSCs and that suppression of LRRK2 kinase activity leads to reduced GBM malignancy and proliferation. In the near future, targeting LRRK2 in patients with high LRRK2-expressing GBM could offer a superior therapeutic strategy and potentially replace current clinical treatment methods.
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Plants are treasure trove of novel compounds that have potential for antifungal chemicals and drugs. In our previous study, we had screened plant extracts obtained from more than eight hundred plant materials collected in Korea, and found that butanol fraction of the Actinostemma lobatum were most potent in suppressing growth of diverse fungal pathogens of plants. Here in this study, we describe further analysis of the butanol fraction, and summarize the results of subsequent antifungal activity test for the sub-fractions against a selected set of plant pathogenic fungi. This line of analyses allowed us to identify the sub-fractions that could account for a significant proportion of observed antifungal activity of initial butanol fraction from A. lobatum. Further analysis of these sub-fractions and determination of structure would provide the shortlist for novel compounds that can be a lead to new agrochemicals.
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The evolutionary trajectory of glioblastoma (GBM) is a multifaceted biological process that extends beyond genetic alterations alone. Here, we perform an integrative proteogenomic analysis of 123 longitudinal glioblastoma pairs and identify a highly proliferative cellular state at diagnosis and replacement by activation of neuronal transition and synaptogenic pathways in recurrent tumors. Proteomic and phosphoproteomic analyses reveal that the molecular transition to neuronal state at recurrence is marked by post-translational activation of the wingless-related integration site (WNT)/ planar cell polarity (PCP) signaling pathway and BRAF protein kinase. Consistently, multi-omic analysis of patient-derived xenograft (PDX) models mirror similar patterns of evolutionary trajectory. Inhibition of B-raf proto-oncogene (BRAF) kinase impairs both neuronal transition and migration capability of recurrent tumor cells, phenotypic hallmarks of post-therapy progression. Combinatorial treatment of temozolomide (TMZ) with BRAF inhibitor, vemurafenib, significantly extends the survival of PDX models. This study provides comprehensive insights into the biological mechanisms of glioblastoma evolution and treatment resistance, highlighting promising therapeutic strategies for clinical intervention.
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Neoplasias Encefálicas , Glioblastoma , Proteogenômica , Animais , Humanos , Glioblastoma/genética , Proteínas Proto-Oncogênicas B-raf , Proteômica , Linhagem Celular Tumoral , Recidiva Local de Neoplasia , Modelos Animais de Doenças , Neoplasias Encefálicas/genética , Resistencia a Medicamentos Antineoplásicos , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Free-living amoebae (FLA) rarely cause human infections but can invoke fatal infections in the central nervous system (CNS). No consensus treatment has been established for FLA infections of the CNS, emphasizing the urgent need to discover or develop safe and effective drugs. Flavonoids, natural compounds from plants and plant-derived products, are known to have antiprotozoan activities against several pathogenic protozoa parasites. The anti-FLA activity of flavonoids has also been proposed, while their antiamoebic activity for FLA needs to be emperically determined. We herein evaluated the antiamoebic activities of 18 flavonoids against Naegleria fowleri and Acanthamoeba species which included A. castellanii and A. polyphaga. These flavonoids showed different profiles of antiamoebic activity against N. fowleri and Acanthamoeba species. Demethoxycurcumin, kaempferol, resveratrol, and silybin (A+B) showed in vitro antiamoebic activity against both N. fowleri and Acanthamoeba species. Apigenin, costunolide, (â)-epicatechin, (â)-epigallocatechin, rosmarinic acid, and (â)-trans-caryophyllene showed selective antiamoebic activity for Acanthamoeba species. Luteolin was more effective for N. fowleri. However, afzelin, berberine, (±)-catechin, chelerythrine, genistein, (+)-pinostrobin, and quercetin did not exhibit antiamoebic activity against the amoeba species. They neither showed selective antiamoebic activity with significant cytotoxicity to C6 glial cells. Our results provide a basis for the anti-FLA activity of flavonoids, which can be applied to develope alternative or supplemental therapeutic agents for FLA infections of the CNS.
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Acanthamoeba , Amebíase , Amoeba , Naegleria fowleri , Humanos , Flavonoides/farmacologia , Amebíase/tratamento farmacológicoRESUMO
Soluble epoxide hydrolase (sEH) is an important enzyme for metabolic and cardiovascular health. sEH converts FFA epoxides (EpFAs), many of which are regulators of various cellular processes, to biologically less active diols. In human studies, diol (sEH product) to EpFA (sEH substrate) ratios in plasma or serum have been used as indices of sEH activity. We previously showed these ratios profoundly decreased in rats during acute feeding, possibly reflecting decreases in tissue sEH activities. The present study was designed to test which tissue(s) these measurements in the blood represent and if factors other than sEH activity, such as renal excretion or dietary intake of EpFAs and diols, significantly alter plasma EpFAs, diols, and/or their ratios. The results show that postprandial changes in EpFAs and diols and their ratios in plasma were very similar to those observed in the liver but not in other tissues, suggesting that the liver is largely responsible for these changes in plasma levels. EpFAs and diols were excreted into the urine, but their levels were not significantly altered by feeding, suggesting that renal excretion of EpFAs and diols may not play a major role in postprandial changes in circulating EpFAs, diols, or their ratios. Diet intake had significant impacts on circulating EpFA and diol levels but not on diol-to-EpFA (D-to-E) ratios, suggesting that these ratios, reflecting sEH activities, may not be significantly affected by the availability of sEH substrates (i.e., EpFAs). In conclusion, changes in FFA D-to-E ratios in plasma may reflect those in the liver, which may in turn represent sEH activities in the liver, and they may not be significantly affected by renal excretion or the dietary intake of EpFAs and diols.
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Epóxido Hidrolases , Compostos de Epóxi , Humanos , Ratos , Animais , Epóxido Hidrolases/metabolismo , Compostos de Epóxi/metabolismo , Fígado/metabolismoRESUMO
Oxylipins, oxidation products of unsaturated free fatty acids (FFAs), are involved in various cellular signaling systems. Among these oxylipins, FFA epoxides are associated with beneficial effects in metabolic and cardiovascular health. FFA epoxides are metabolized to diols, which are usually biologically less active, by soluble epoxide hydrolase (sEH). Plasma epoxide-diol ratios have been used as indirect measures of sEH activity. This study was designed to examine the effects of acute elevation of individual plasma FFAs on a variety of oxylipins, particularly epoxides, diols, and their ratios. We tested if FFA epoxide-diol ratios are altered by circulating FFA levels (i.e., substrate availability) independent of sEH activity. Wistar rats received a constant intravenous infusion of olive (70% oleic acid (OA)), safflower seed (72% linoleic acid (LA)), and fish oils (rich in ω-3 FFAs) as emulsions to selectively raise OA, LA, and ω-3 FFAs (eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)), respectively. As expected, olive, safflower seed, and fish oil infusions selectively raised plasma OA (57%), LA (87%), EPA (70%), and DHA (54%), respectively (p < 0.05 for all). Raising plasma FFAs exerted substrate effects to increase hepatic and plasma epoxide and diol levels. These increases in epoxides and diols occurred to similar extents, resulting in no significant changes in epoxide-diol ratios. These data suggest that epoxide-diol ratios, often used as indices of sEH activity, are not affected by substrate availability or altered plasma FFA levels and that epoxide-diol ratios may be used to compare sEH activity between conditions of different circulating FFA levels.
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Ácidos Graxos não Esterificados , Oxilipinas , Ratos , Animais , Ácidos Graxos não Esterificados/metabolismo , Oxilipinas/metabolismo , Epóxido Hidrolases/metabolismo , Compostos de Epóxi/metabolismo , Ratos Wistar , Ácidos Graxos Insaturados/metabolismo , Óleos de Peixe , Ácido Eicosapentaenoico , Ácido Linoleico , Ácidos Docosa-Hexaenoicos , Ácido OleicoRESUMO
Radiation therapy (RT) provides therapeutic benefits for patients with glioblastoma (GBM), but inevitably induces poorly understood global changes in GBM and its microenvironment (TME) that promote radio-resistance and recurrence. Through a cell surface marker screen, we identified that CD142 (tissue factor or F3) is robustly induced in the senescence-associated ß-galactosidase (SA-ßGal)-positive GBM cells after irradiation. F3 promotes clonal expansion of irradiated SA-ßGal+ GBM cells and orchestrates oncogenic TME remodeling by activating both tumor-autonomous signaling and extrinsic coagulation pathways. Intratumoral F3 signaling induces a mesenchymal-like cell state transition and elevated chemokine secretion. Simultaneously, F3-mediated focal hypercoagulation states lead to activation of tumor-associated macrophages (TAMs) and extracellular matrix (ECM) remodeling. A newly developed F3-targeting agent potently inhibits the aforementioned oncogenic events and impedes tumor relapse in vivo. These findings support F3 as a critical regulator for therapeutic resistance and oncogenic senescence in GBM, opening potential therapeutic avenues.
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Neoplasias Encefálicas , Glioblastoma , Humanos , Glioblastoma/tratamento farmacológico , Glioblastoma/genética , Glioblastoma/radioterapia , Tromboplastina , Linhagem Celular Tumoral , Recidiva Local de Neoplasia , Transdução de Sinais , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/radioterapia , Neoplasias Encefálicas/metabolismo , Microambiente TumoralRESUMO
This study evaluated the effects of Rorippa cantoniensis (Lour.) ohwi extract (RCE) on factors associated with inflammation-related skin lesions in RAW 264.7 and HaCaT cells. RCE inhibited the levels of proinflammatory mediators and cytokines such as nitric oxide (NO), prostaglandin E2 (PGE2), interleukin (IL)-6, and tumor necrosis factor (TNF)-α in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. In addition, RCE significantly inhibited the expression of chemokines and cytokines such as MDC/CCL22, TARC/CCL17, RANTES/CCL5, CTSS, IL-6, IL-1ß, and TNF-α in HaCaT cells costimulated by TNF-α and interferon (IFN)-γ in a concentration-dependent manner. These results suggest that RCE attenuated the TNF-α- and IFN-γ-induced release of proinflammatory chemokines and cytokines probably by suppressing the activation of MAPK (JNK and p38), NF-κB, and STAT1 signaling. Moreover, RCE significantly increased the expression of skin components such as hyaluronic acid and aquaporin, which play important roles in the physical and chemical barriers of the skin. These results suggest that RCE has significant anti-inflammatory and antiatopic activities, which may be beneficial for the topical treatment of inflammatory skin disorders.
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Células HaCaT , Rorippa , Animais , Camundongos , Humanos , Rorippa/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Queratinócitos , Linhagem Celular , Citocinas/metabolismo , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/metabolismo , NF-kappa B/metabolismo , Quimiocinas/metabolismo , Células RAW 264.7RESUMO
OBJECTIVE: For early-stage orbital mucosa-associated lymphoid tissue lymphoma (MALToma), radiotherapy (RT) is known to be the treatment of choice. The classical recommended treatment field is the entire ipsilateral orbit, exposing normal orbital structures such as the lacrimal gland and lens, which are sensitive to moderate doses of radiation, to the full treatment dose. Herein we aimed to evaluate the clinical outcomes and dosimetric values in patients with orbital MALToma who received RT. DESIGN: This study was a retrospective study. PARTICIPANTS: Forty patients with orbital MALToma treated with curative RT. METHODS: The patients were classified into the conjunctival RT (nâ¯=â¯23), partial-orbit RT (nâ¯=â¯10), and whole-orbit RT (nâ¯=â¯7) groups. The treatment outcomes and dosimetric values of the orbital structures were reviewed. RESULTS: We found the 5-year local, contralateral orbit, and overall relapse rates to be 5.0%, 5.9%, and 16.0%, respectively. Local relapse events occurred in 2 patients in the conjunctival RT group. No relapse was observed in the partial-orbit RT group. Whole-orbit RT caused significantly higher rates of dry eyes during treatment. The partial-orbit RT group showed a significantly lower ipsilateral eyeball mean dose and ipsilateral eyelid mean dose than the other groups. CONCLUSION: Partial-orbit RT showed encouraging clinical, toxicity, and dosimetric outcomes in patients with orbital MALToma and has the potential to be a treatment option for such patients.
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Recent studies indicate that signaling molecules traditionally associated with central nervous system function play critical roles in cancer. Dopamine receptor signaling is implicated in various cancers including glioblastoma (GBM) and it is a recognized therapeutic target, as evidenced by recent clinical trials with a selective dopamine receptor D2 (DRD2) inhibitor ONC201. Understanding the molecular mechanism(s) of the dopamine receptor signaling will be critical for development of potent therapeutic options. Using the human GBM patient-derived tumors treated with dopamine receptor agonists and antagonists, we identified the proteins that interact with DRD2. DRD2 signaling promotes glioblastoma (GBM) stem-like cells and GBM growth by activating MET. In contrast, pharmacological inhibition of DRD2 induces DRD2-TRAIL receptor interaction and subsequent cell death. Thus, our findings demonstrate a molecular circuitry of oncogenic DRD2 signaling in which MET and TRAIL receptors, critical factors for tumor cell survival and cell death, respectively, govern GBM survival and death. Finally, tumor-derived dopamine and expression of dopamine biosynthesis enzymes in a subset of GBM may guide patient stratification for DRD2 targeting therapy.
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Glioblastoma , Humanos , Linhagem Celular Tumoral , Dopamina , Glioblastoma/patologia , Receptores do Ligante Indutor de Apoptose Relacionado a TNF , Transdução de Sinais , Receptores de Dopamina D2/metabolismoRESUMO
Despite producing a panoply of potential cancer-specific targets, the proteogenomic characterization of human tumors has yet to demonstrate value for precision cancer medicine. Integrative multi-omics using a machine-learning network identified master kinases responsible for effecting phenotypic hallmarks of functional glioblastoma subtypes. In subtype-matched patient-derived models, we validated PKCδ and DNA-PK as master kinases of glycolytic/plurimetabolic and proliferative/progenitor subtypes, respectively, and qualified the kinases as potent and actionable glioblastoma subtype-specific therapeutic targets. Glioblastoma subtypes were associated with clinical and radiomics features, orthogonally validated by proteomics, phospho-proteomics, metabolomics, lipidomics and acetylomics analyses, and recapitulated in pediatric glioma, breast and lung squamous cell carcinoma, including subtype specificity of PKCδ and DNA-PK activity. We developed a probabilistic classification tool that performs optimally with RNA from frozen and paraffin-embedded tissues, which can be used to evaluate the association of therapeutic response with glioblastoma subtypes and to inform patient selection in prospective clinical trials.
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Proteína Quinase Ativada por DNA , Glioblastoma , Proteína Quinase C-delta , Humanos , Proteína Quinase Ativada por DNA/genética , Glioblastoma/tratamento farmacológico , Glioblastoma/genética , Multiômica , Proteína Quinase C-delta/genética , ProteômicaRESUMO
LZTR1 is the substrate-specific adaptor of a CUL3-dependent ubiquitin ligase frequently mutated in sporadic and syndromic cancer. We combined biochemical and genetic studies to identify LZTR1 substrates and interrogated their tumor-driving function in the context of LZTR1 loss-of-function mutations. Unbiased screens converged on EGFR and AXL receptor tyrosine kinases as LZTR1 interactors targeted for ubiquitin-dependent degradation in the lysosome. Pathogenic cancer-associated mutations of LZTR1 failed to promote EGFR and AXL degradation, resulting in dysregulated growth factor signaling. Conditional inactivation of Lztr1 and Cdkn2a in the mouse nervous system caused tumors in the peripheral nervous system including schwannoma-like tumors, thus recapitulating aspects of schwannomatosis, the prototype tumor predisposition syndrome sustained by LZTR1 germline mutations. Lztr1- and Cdkn2a-deleted tumors aberrantly accumulated EGFR and AXL and exhibited specific vulnerability to EGFR and AXL coinhibition. These findings explain tumorigenesis by LZTR1 inactivation and offer therapeutic opportunities to patients with LZTR1-mutant cancer. SIGNIFICANCE: EGFR and AXL are substrates of LZTR1-CUL3 ubiquitin ligase. The frequent somatic and germline mutations of LZTR1 in human cancer cause EGFR and AXL accumulation and deregulated signaling. LZTR1-mutant tumors show vulnerability to concurrent inhibition of EGFR and AXL, thus providing precision targeting to patients affected by LZTR1-mutant cancer. This article is highlighted in the In This Issue feature, p. 517.
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Neurilemoma , Fatores de Transcrição , Animais , Humanos , Camundongos , Carcinogênese , Transformação Celular Neoplásica , Receptores ErbB/genética , Mutação , Neurilemoma/genética , Neurilemoma/metabolismo , Neurilemoma/patologia , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Ubiquitinas/genéticaRESUMO
Plants produce chemicals of immense diversity that provide great opportunities for development of new antifungal compounds. In search for environment-friendly alternatives to the fungicide of current use, we screened plant extracts obtained from more than eight hundred plant materials collected in Korea for their antifungal activity against the model plant pathogenic fungus, Magnaporthe oryzae. This initial screening identified antifungal activities from the eleven plant extract samples, among which nine showed reproducibility in the follow-up screening. These nine samples were able to suppress not only M. oryzae but also other fungal pathogens. Interestingly, the plant extracts obtained from Actinostemma lobatum comprised five out of eight samples, and were the most effective in their antifungal activity. We found that butanol fraction of the A. lobatum extract is the most potent. Identification and characterization of antifungal substances in the A. lobatum extracts would provide the promising lead compounds for new fungicide.
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Acanthamoeba keratitis (AK) is an infectious ocular disease which is difficult to diagnose correctly and cure. Development of an effective and safe therapeutic drug for AK is needed. Our preliminary screening of more than 200 extracts from wild plants collected in Korea suggested the potential amoebicidal activity of Phragmites australis (Cav.) Trin. ex Steud. extract (PAE) against Acanthamoeba species. Here, we aimed to analyze the amoebicidal activity of PAE on Acanthamoeba and its underlying amoebicidal mechanism. PAE induced amoebicidal activity against both A. castellanii and A. polyphaga trophozoites, while it showed low cytotoxicity in human corneal epithelial cells (HCE-2) and human retinal pigment epithelial cells (ARPE-19). Transmission electron microscopy analysis showed subcellular morphological changes, such as increased granules, abnormal mitochondria, and atypical cyst wall formation, in the PAE-treated A. castellanii. Fluorometric apoptosis assay and TUNEL assay revealed apoptosis-like programmed cell death (PCD) in the PAE-treated A. castellanii. The PAE treatment increased reactive oxygen species production and reduced mitochondrial membrane potential in the amoeba. The enhanced expression of autophagy-associated genes was also detected. These results suggested that PAE exerted a promising amoebicidal effect on A. castellanii trophozoites via the PCD pathway. PAE could be a potential candidate for developing a therapeutic drug for AK.
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The purpose of this study was to examine how coaching styles affect athletes' moral disengagement. To achieve our objectives, we examined the relationships among perceived coaching types, pride, and moral disengagement in the context of elite taekwondo athletes (N = 322). Direct and indirect effects among coaching types, pride, and moral disengagement were assessed through path analysis. The results indicated that the autonomy-support coaching type reduced moral disengagement by decreasing hubristic pride, while the controlled coaching type increased moral disengagement through hubristic pride. Our study found a chain of effects according to the controlled coaching type perceived by taekwondo athletes, hubristic pride, and moral disengagement; therefore, the controlled coaching type and hubristic pride should be closely managed in sport society, as they elicit greater moral disengagement. Managerial strategies to diminish hubristic pride through the autonomy-support coaching type are recommended.
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Artes Marciais , Tutoria , Atletas , Emoções , Humanos , Princípios MoraisRESUMO
Persicaria maackiana (Regel) Nakai ex T. Mori (1922), a species of the Polygonaceae family, is an annual plant widely distributed in Northeast Asia. We aimed to sequence the complete chloroplast genome of P. maackiana using Illumina HiSeq paired-end sequencing. The chloroplast genome was determined to be 160,635 bp. The complete chloroplast genome contained 129 genes, including 84 protein-coding genes, 37 tRNA, and eight rRNA genes. Phylogenetic analysis of the chloroplast genome sequences of 15 Polygonaceae plants revealed that P. maackiana was most closely related to P. perfoliata. Our findings might be useful for future phylogenetic studies of Polygonaceae.
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BACKGROUND/AIMS: The study investigated the incidence of thromboembolic events (TEE) in head and neck (H&N) cancer patients who received concurrent chemoradiotherapy (CCRT) with cisplatin, and analyzed the factors affecting TEE occurrence. METHODS: Two hundred and fifty-seven patients who started CCRT with cisplatin for H&N cancer from January 2005 to December 2019 were analyzed. RESULTS: TEE occurred in five patients, an incidence rate of 1.9%. The 2-, 4-, and 6-month cumulative incidences of TEE were 0.8%, 1.6%, and 1.9%, respectively. Khorana score was the only factor associated with TEE occurrence (p = 0.010). CONCLUSION: The incidence of TEE in H&N cancer patients who underwent CCRT with cisplatin was relatively low when compared to other types of cancer. However, patients with a high Khorana score require more careful surveillance for possible TEE occurrence.
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Cisplatino , Neoplasias de Cabeça e Pescoço , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Quimiorradioterapia/efeitos adversos , Cisplatino/efeitos adversos , Neoplasias de Cabeça e Pescoço/terapia , Humanos , IncidênciaRESUMO
BACKGROUND/AIMS: The optimal treatment (Tx) for epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) patients with brain metastasis (BM) remains to be determined. METHODS: A retrospective review was conducted on 77 NSCLC patients with synchronous BM who underwent first-line EGFR-tyrosine kinase inhibitor (TKI) Tx. The outcomes of patients were analyzed according to the clinicopathological characteristics including local Tx modalities. RESULTS: Fifty-nine patients underwent local Tx for BM (gamma knife surgery [GKS], 37; whole brain radiotherapy [WBRT], 18; others, four) concurrently or sequentially with EGFR-TKI. Patients treated with TKI alone showed significantly lower incidence of central nervous system (CNS) symptoms. The median progression-free survival (PFS) and overall survival (OS) after the initiation of EGFR-TKI for all patients were 9 and 19 months, respectively. In 60 patients with follow-up brain imaging, the median time to CNS progression was 15 months. Patients with EGFR exon 19 deletion had a significantly longer median OS than those with other mutations including L858R (23 months vs. 17 months). Other clinical characteristics, including CNS symptoms, number of BM, and the use of local Tx were not associated with OS, as well as PFS. In terms of the local optimal Tx modality, no difference was found between GKS and WBRT in the OS and PFS. CONCLUSION: This study suggests that EGFR-TKI may result in a favorable outcome in NSCLC patients with synchronous BM, especially in deletion 19 mutant, regardless of the extent of BM lesions or local Tx modalities. Patients with asymptomatic BM can be treated with EGFR-TKI and careful surveillance.
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Neoplasias Encefálicas , Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/secundário , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/genética , Receptores ErbB/genética , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Mutação , Inibidores de Proteínas Quinases/efeitos adversos , Estudos RetrospectivosRESUMO
Extracellular potassium (K+) homeostasis is achieved by a concerted effort of multiple organs and tissues. A limitation in studies of K+ homeostasis is inadequate techniques to quantify K+ fluxes into and out of organs and tissues in vivo. The goal of the present study was to test the feasibility of a novel approach to estimate K+ distribution and fluxes in vivo using stable K+ isotopes. 41K was infused as KCl into rats consuming control or K+-deficient chow (n = 4 each), 41K-to-39K ratios in plasma and red blood cells (RBCs) were measured by inductively coupled plasma mass spectrometry, and results were subjected to compartmental modeling. The plasma 41K/39K increased during 41K infusion and decreased upon infusion cessation, without altering plasma total K+ concentration ([K+], i.e., 41K + 39K). The time course of changes was analyzed with a two-compartmental model of K+ distribution and elimination. Model parameters, representing transport into and out of the intracellular pool and renal excretion, were identified in each rat, accurately predicting decreased renal K+ excretion in rats fed K+-deficient vs. control diet (P < 0.05). To estimate rate constants of K+ transport into and out of RBCs, 41K/39K were subjected to a simple model, indicating no effects of the K+-deficient diet. The findings support the feasibility of the novel stable isotope approach to quantify K+ fluxes in vivo and sets a foundation for experimental protocols using more complex models to identify heterogeneous intracellular K+ pools and to answer questions pertaining to K+ homeostatic mechanisms in vivo.