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1.
BMC Gastroenterol ; 23(1): 455, 2023 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-38129820

RESUMO

BACKGROUND: Gastric cancer (GC) is considered the sixth highly prevailing malignant neoplasm and is ranked third in terms of cancer mortality rates. To enable an early and efficient diagnosis of GC, it is important to detect the fundamental processes involved in the oncogenesis and progression of gastric malignancy. The understanding of molecular signaling pathways can facilitate the development of more effective therapeutic strategies for GC patients. METHODS: The screening of genes that exhibited differential expression in early and advanced GC was performed utilizing the Gene Expression Omnibus databases (GSE3438). Based on this, the protein and protein interaction network was constructed to screen for hub genes. The resulting list of hub genes was evaluated with bioinformatic analysis and selected genes were validated the protein expression by immunohistochemistry (IHC). Finally, a competing endogenous RNA network of GC was constructed. RESULTS: The three genes (ITGB1, LUM, and COL5A2) overexpressed in both early and advanced GC were identified for the first time. Their upregulation has been linked with worse overall survival (OS) time in patients with GC. Only LUM was identified as an independent risk factor for OS among GC patients by means of additional analysis. IHC results demonstrated that the expression of LUM protein was increased in GC tissue, and was positively associated with the pathological T stage. LUM expression can effectively differentiate tumorous tissue from normal tissue (area under the curve = 0.743). The area under 1-, 3-, and 5-year survival relative operating characteristics were greater than 0.6. Biological function enrichment analyses suggested that the genes related to LUM expression were involved in extracellular matrix development-related pathways and enriched in several cancer-related pathways. LUM affects the infiltration degree of cells linked to the immune system in the tumor microenvironment. In GC progression, the AC117386.2/hsa-miR-378c/LUM regulatory axis was also identified. CONCLUSION: Collectively, a thorough bioinformatics analysis was carried out and an AC117386.2/hsa-miR-378c/LUM regulatory axis in the stomach adenocarcinoma dataset was detected. These findings should serve as a guide for future experimental investigations and warrant confirmation from larger studies.


Assuntos
MicroRNAs , Neoplasias Gástricas , Humanos , Biologia Computacional , Prognóstico , Neoplasias Gástricas/genética , Microambiente Tumoral
2.
Bioengineered ; 13(4): 8503-8514, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35332852

RESUMO

Cervical squamous cell carcinoma (CSCC), the most common cervical malignancy, is more likely to invade and metastasize than other cervical cancers. miR-125a, a tumor suppressor gene, has been confirmed to be associated with cancer metastasis. However, the role of miR-125a in CSCC and the underlying mechanism are unknown. miR-125a expression was confirmed by real-time quantitative PCR (RT-qPCR), and the Rad51 expression level was measured by western blotting analysis. CSCC cell proliferation, migration and invasion were assessed with functional assays, including CCK-8, colony formation, wound healing and Transwell assays. Our data confirmed that miR-125a is expressed at low levels in CSCC tissues and cells. Functionally, the overexpression of miR-125a greatly prevented the proliferation, migration and invasion of CSCC cells, and the inhibition of miR-125a expression strongly enhanced these behaviors in CSCC cells. Moreover, the expression of Rad51, a miR-125a target gene, greatly reversed the miR-125-mediated inhibition of CSCC cell proliferation, migration and invasion. In addition, we discovered that miR-125a downregulated the levels of phosphorylated PI3K, AKT and mTOR through Rad51 in CSCC cells. miR-125a, a tumor suppressor, can attenuate the malignant behaviors of CSCC cells by targeting Rad51. Therefore, the miR-125a/Rad51 axis might be a target for CSCC therapy.


Assuntos
Carcinoma de Células Escamosas , MicroRNAs , Rad51 Recombinase , Neoplasias do Colo do Útero , Carcinoma de Células Escamosas/genética , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células/genética , Feminino , Humanos , MicroRNAs/genética , Rad51 Recombinase/genética , Neoplasias do Colo do Útero/genética
3.
Artigo em Inglês | MEDLINE | ID: mdl-32149634

RESUMO

A two-dimensional (2-D) array with a small pitch (approximately 0.5λ in medium) can achieve complete 3-D control of ultrasound beams without grating lobes and enable the generation of multiple focal spots simultaneously, which is a desired tool for noninvasive therapy. However, the large electrical impedance of 2-D array elements owing to their small size results in a low energy transfer efficiency between a 2-D array and an electrical system, thereby limiting their practical applications. This article presents the development of a 1-MHz 256-element 2-D array ultrasonic transducer of low electrical impedance based on a new Sm-doped Pb(Mg1/3Nb2/3)O3-PbTiO3 (Sm-PMN-PT) piezoceramic with ultrahigh dielectric permittivity. The electrical impedance of the array element is decreased by 3.4 times as the Sm-PMN-PT replacing commercial PZT-5H. Consequently, the output acoustic pressure of the 2-D array made of Sm-PMN-PT ceramic is approximately twice that of the 2-D array made of PZT-5H ceramic under the same excitation conditions. Array elements are spaced at a 1.1-mm pitch ( 0.71λ in water), enabling a large steering range of the ultrasound beam. A multiple-target blood-brain barrier opening in vivo is demonstrated using the proposed 2-D array with electronic focusing and steering. The obtained results indicate that the 2-D array made of Sm-PMN-PT ceramic is promising for practical use in low-intensity ultrasound therapy applications.


Assuntos
Cerâmica/química , Metais/química , Transdutores , Terapia por Ultrassom/instrumentação , Animais , Barreira Hematoencefálica/efeitos da radiação , Encéfalo/efeitos da radiação , Desenho de Equipamento , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Crânio/fisiologia
4.
Sensors (Basel) ; 19(8)2019 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-30999576

RESUMO

Neurostimulation has proved to be an effective method for the restoration of visual perception lost due to retinal diseases. However, the clinically available retinal neurostimulation method is based on invasive electrodes, making it a high-cost and high-risk procedure. Recently, ultrasound has been demonstrated to be an effective way to achieve noninvasive neurostimulation. In this work, a novel racing array transducer with a contact lens shape is proposed for ultrasonic retinal stimulation. The transducer is flexible and placed outside the eyeball, similar to the application of a contact lens. Ultrasound emitted from the transducer can reach the retina without passing through the lens, thus greatly minimizing the acoustic absorption in the lens. The discretized Rayleigh-Sommerfeld method was employed for the acoustic field simulation, and patterned stimulation was achieved. A 5 MHz racing array transducer with different element numbers was simulated to optimize the array configuration. The results show that a 512-element racing array is the most appropriate configuration considering the necessary tradeoff between the element number and the stimulation resolution. The stimulation resolution at a focus of 24 mm is about 0.6 mm. The obtained results indicate that the proposed racing array design of the ultrasound transducer can improve the feasibility of an ultrasound retinal prosthesis.

5.
J Neural Eng ; 16(3): 036006, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30818304

RESUMO

OBJECTIVE: It has been shown that low-intensity ultrasound (LIUS) can suppress seizures in some laboratory studies. However, the mechanism of the suppression effect of LIUS remains unclear. The goal of this study is to investigate the modulation effects of focused LIUS on epileptiform discharges in mouse hippocampal slices as well as the underlying mechanism. APPROACH: Epileptiform discharges in hippocampal slices of 8 d-old mice were induced by low-Mg2+ artificial cerebrospinal fluid and recorded by a micro-electrode array in vitro. LIUS was delivered to hippocampal slices to investigate its modulation effects on epileptiform discharges. Pharmacological experiments were conducted to study the mechanism of the modulation effects. MAIN RESULTS: LIUS suppressed the amplitude, rate and duration of ictal discharges. For inter-ictal discharges, LIUS suppressed the amplitude but facilitated the rate. LIUS suppressed the spontaneous spiking activities of pyramidal neurons in CA3, and the suppression effect was eliminated by Kaliotoxin. The suppression effect of LIUS on epileptiform discharges was weakened when the perfusion was mixed with Kaliotoxin. SIGNIFICANCE: Those findings demonstrate that LIUS suppresses the epileptiform discharges in 8 d-old mouse hippocampal slices and that its suppression effect can mainly attributed to the activation of mechanosensitive Kv1.1 channels.


Assuntos
Potenciais de Ação/efeitos dos fármacos , Potenciais de Ação/fisiologia , Hipocampo/efeitos dos fármacos , Hipocampo/fisiologia , Magnésio/toxicidade , Ondas Ultrassônicas , Animais , Epilepsia/induzido quimicamente , Epilepsia/fisiopatologia , Epilepsia/terapia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Técnicas de Cultura de Órgãos , Convulsões/induzido quimicamente , Convulsões/fisiopatologia , Convulsões/terapia , Terapia por Ultrassom/métodos
6.
Ultrasound Med Biol ; 45(3): 811-822, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30598192

RESUMO

Precisely evaluating the characteristics of a glioma tumor in vivo is challenging when performing surgical resection clinically. The infiltration characteristics of a tumor make precise resection difficult because of uncertainties about the surrounding vasculature and the relationships with functional structures. Magnetic resonance imaging is routinely used to distinguish the area of a glioma, but it cannot resolve details of the vascular network around or inside the tumor. Ultrasound imaging is a real-time imaging modality that has been applied clinically in intra-operative surgery, and the sensitivity of flow measurements in the brain is improved by ultrafast plane wave imaging. This study applies a plane wave-based power Doppler imaging method to visualize the blood flow distribution in glioma models in vivo. This new imaging method makes it possible to delineate the flow structure of a glioma tumor in the brain of a small animal. The tumor can be distinguished from normal brain tissue, and different sections of the tumor contain different flow structures. The normalized blood flow intensities (mean ± standard deviation) within regions of interest were 0.33 ± 0.13, 0.72 ± 0.15, 0.36 ± 0.23 and 0.06 ± 0.07 for the type I normal rat, type I glioma rat, type II normal rat and type II glioma rat, respectively. Quantification analysis verified the feasibility of using this plane wave-based Doppler imaging method to evaluate brain tumors in small animals.


Assuntos
Neoplasias Encefálicas/diagnóstico por imagem , Glioma/diagnóstico por imagem , Ultrassonografia Doppler/métodos , Animais , Encéfalo/diagnóstico por imagem , Modelos Animais de Doenças , Feminino , Ratos , Ratos Sprague-Dawley
7.
IEEE Trans Biomed Eng ; 66(1): 217-224, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-29993389

RESUMO

Neuromodulation is a fundamental method for obtaining basic information about neuronal circuits for use in treatments for neurological and psychiatric disorders. Ultrasound stimulation has become a promising approach for noninvasively inducing neuromodulation in animals and humans. However, the previous investigations were subject to substantial limitations, due to most of them involving anesthetized and fixed small-animal models. Studies of awake and freely moving animals are needed, but the currently used ultrasound devices are too bulky to be applied to a freely moving animal. This study is the first time to design and fabricate a miniature and lightweight head-mounted ultrasound stimulator for inducing neuromodulation in freely moving mice. The main components of the stimulator include a miniature piezoelectric ceramic, a concave epoxy acoustic lens, and housing and connection components. The device was able to induce action potentials recorded in situ and evoke head-turning behaviors by stimulating the primary somatosensory cortex barrel field of the mouse. These findings indicate that the proposed method can be used to induce noninvasive neuromodulation in freely moving mice. This novel method could potentially lead to the application of ultrasonic neuromodulation in more-extensive neuroscience investigations.


Assuntos
Estimulação Física/instrumentação , Ultrassom/instrumentação , Animais , Comportamento Animal/efeitos da radiação , Desenho de Equipamento , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Estimulação Elétrica Nervosa Transcutânea
8.
Artigo em Inglês | MEDLINE | ID: mdl-29994254

RESUMO

Neuromodulation is an important method for investigating neural circuits and treating neurological and psychiatric disorders. Multiple-target neuromodulation is considered an advanced technology for the flexible optimization of modulation effects. However, traditional methods such as electrical and magnetic stimulations are not convenient for multiple-target applications due to their disadvantages of invasiveness or poor spatial resolution. Ultrasonic neuromodulation is a new noninvasive method that has gained wide attention in the field of neuroscience, and it is potentially able to support multiple-target stimulation by allocating multiple focal points in the brain using an array transducer. However, there are no reports in the literature of the efficacy of this technical concept, and an imaging tool for localizing the stimulation area for evaluating the neural effects in vivo has been lacking. In this study, we designed and fabricated a new system specifically for imaging-guided dual-target neuromodulation. The design of the array transducer and overall system is described in detail. The stimulation points were selectable on a B-mode image. In vivo experiments were carried out in mice, in which forelimbs shaking responses and electromyography outcomes were induced by changing the stimulation targets. The system could be a valuable tool for imaging-guided multiple-target stimulation in various neuroscience applications.


Assuntos
Encéfalo/diagnóstico por imagem , Estimulação Elétrica Nervosa Transcutânea/métodos , Ultrassonografia de Intervenção/instrumentação , Ultrassonografia de Intervenção/métodos , Animais , Desenho de Equipamento , Membro Anterior/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Crânio/fisiologia , Transdutores
9.
IEEE Trans Neural Syst Rehabil Eng ; 26(5): 969-976, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29752231

RESUMO

Significant progress has been made recently in treating neurological blindness using implantable visual prostheses. However, implantable medical devices are highly invasive and subject to many safety, efficacy, and cost issues. The discovery that ultrasound (US) may be useful as a noninvasive neuromodulation tool has aroused great interest in the field of acoustic retinal prostheses (ARPs). We have investigated the responsiveness of rat retinal ganglion cells (RGCs) to low-frequency focused US stimulation (LFUS) at 2.25 MHz and characterized the neurophysiological properties of US responses by performing in vitro multielectrode array recordings. The results show that LFUS can reliably activate RGCs. The US-induced responses did not correspond to the standard light responses and varied greatly among cell types. Moreover, dual-peak responses to US stimulation were observed that have not been reported previously. The temporal response properties of RGCs, including their latency, firing rate, and response type, were modulated by the acoustic intensity. These findings suggest the presence of a temporal neuromodulation effect of LFUS and potentially open a new avenue in the development of ARP.


Assuntos
Células Ganglionares da Retina/fisiologia , Ultrassom , Próteses Visuais , Animais , Microeletrodos , Estimulação Luminosa , Desenho de Prótese , Ratos , Ratos Sprague-Dawley , Células Ganglionares da Retina/classificação , Transdutores
10.
Int J Biol Sci ; 13(10): 1242-1253, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29104491

RESUMO

The effects of Ca2+ sparks on cerebral artery smooth muscle cells (CASMCs) and airway smooth muscle cells (ASMCs) tone, as well as the underlying mechanisms, are not clear. In this investigation, we elucidated the underlying mechanisms of the distinct effects of Ca2+ sparks on cerebral artery smooth muscle cells (CASMCs) and airway smooth muscle cells (ASMCs) tone. In CASMCs, owing to the functional loss of Ca2+-activated Cl- (Clca) channels, Ca2+ sparks activated large-conductance Ca2+-activated K+ channels (BKs), resulting in a decreases in tone against a spontaneous depolarization-caused high tone in the resting state. In ASMCs, Ca2+ sparks induced relaxation through BKs and contraction via Clca channels. However, the integrated result was contraction because Ca2+ sparks activated BKs prior to Clca channels and Clca channels-induced depolarization was larger than BKs-caused hyperpolarization. However, the effects of Ca2+ sparks on both cell types were determined by L-type voltage-dependent Ca2+ channels (LVDCCs). In addition, compared with ASMCs, CASMCs had great and higher amplitude Ca2+ sparks, a higher density of BKs, and higher Ca2+ and voltage sensitivity of BKs. These differences enhanced the ability of Ca2+ sparks to decrease CASMC and to increase ASMC tone. The higher Ca2+ and voltage sensitivity of BKs in CASMCs than ASMCs were determined by the ß1 subunits. Moreover, Ca2+ sparks showed the similar effects on human CASMC and ASMC tone. In conclusions, Ca2+ sparks decrease CASMC tone and increase ASMC tone, mediated by BKs and Clca channels, respectively, and finally determined by LVDCCs.


Assuntos
Sinalização do Cálcio/fisiologia , Cálcio/metabolismo , Músculo Liso/metabolismo , Animais , Sinalização do Cálcio/genética , Artérias Cerebrais/metabolismo , Artérias Cerebrais/fisiologia , Humanos , Camundongos , Músculo Liso/fisiologia , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/fisiologia , Miócitos de Músculo Liso/metabolismo , Miócitos de Músculo Liso/fisiologia , Técnicas de Patch-Clamp
11.
Artigo em Inglês | MEDLINE | ID: mdl-27239213

RESUMO

Cortex phellodendri is used to reduce fever and remove dampness and toxin. Berberine is an active ingredient of C. phellodendri. Berberine from Argemone ochroleuca can relax airway smooth muscle (ASM); however, whether the nonberberine component of C. phellodendri has similar relaxant action was unclear. An n-butyl alcohol extract of C. phellodendri (NBAECP, nonberberine component) was prepared, which completely inhibits high K(+)- and acetylcholine- (ACH-) induced precontraction of airway smooth muscle in tracheal rings and lung slices from control and asthmatic mice, respectively. The contraction induced by high K(+) was also blocked by nifedipine, a selective blocker of L-type Ca(2+) channels. The ACH-induced contraction was partially inhibited by nifedipine and pyrazole 3, an inhibitor of TRPC3 and STIM/Orai channels. Taken together, our data demonstrate that NBAECP can relax ASM by inhibiting L-type Ca(2+) channels and TRPC3 and/or STIM/Orai channels, suggesting that NBAECP could be developed to a new drug for relieving bronchospasm.

13.
Guang Pu Xue Yu Guang Pu Fen Xi ; 36(6): 1910-5, 2016 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-30053352

RESUMO

In order to investigate the effect of long-term (1991­2013) K fertilizer deficiency and surplus on potassium-bearing mineral and K nutrition of purple soil-soil primary, clay mineral composition and potassium (K) nutrition were determined on the long-term experiment of fertility and fertilizer efficiency in neutral purple soil by using X-ray diffraction (XRD) analysis technique. Five soil samples were selected from soil samples library for soil mineral analysis, including original soil, which preserved in 1991 before the experiment carrying out; K deficient treatment for 12 years and 22 years, which means no K fertilizer was applied during 1991­2003 and 1991­2013, respectively; and K surplus treatment for 12 years and 22 years, which means excess K fertilizer was applied during 1991­2003 and 1991­2013, separately. The result showed that, soil potassium-bearing primary mineral, such as mica, potassium feldspar, had apparently weathered and slaked for the K deficient treatment and the weathered extent gradually aggravated following fertilization ages, demonstrating fertilization for 22 years<12years

14.
PLoS One ; 10(3): e0121566, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25822280

RESUMO

The participation of large-conductance Ca2+ activated K+ channels (BKs) in chloroquine (chloro)-induced relaxation of precontracted airway smooth muscle (ASM) is currently undefined. In this study we found that iberiotoxin (IbTx, a selective inhibitor of BKs) and chloro both completely blocked spontaneous transient outward currents (STOCs) in single mouse tracheal smooth muscle cells, which suggests that chloro might block BKs. We further found that chloro inhibited Ca2+ sparks and caffeine-induced global Ca2+ increases. Moreover, chloro can directly block single BK currents completely from the intracellular side and partially from the extracellular side. All these data indicate that the chloro-induced inhibition of STOCs is due to the blockade of chloro on both BKs and ryanodine receptors (RyRs). We also found that low concentrations of chloro resulted in additional contractions in tracheal rings that were precontracted by acetylcholine (ACH). Increases in chloro concentration reversed the contractile actions to relaxations. In the presence of IbTx or paxilline (pax), BK blockers, chloro-induced contractions were inhibited, although the high concentrations of chloro-induced relaxations were not affected. Taken together, our results indicate that chloro blocks BKs and RyRs, resulting in abolishment of STOCs and occurrence of contraction, the latter will counteract the relaxations induced by high concentrations of chloro.


Assuntos
Canais de Potássio Ativados por Cálcio de Condutância Alta/fisiologia , Músculo Liso/fisiologia , Animais , Bloqueadores dos Canais de Cálcio/farmacologia , Sinalização do Cálcio/efeitos dos fármacos , Cloroquina/farmacologia , Técnicas In Vitro , Canais de Potássio Ativados por Cálcio de Condutância Alta/antagonistas & inibidores , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Contração Muscular/efeitos dos fármacos , Contração Muscular/fisiologia , Músculo Liso/efeitos dos fármacos , Miócitos de Músculo Liso/efeitos dos fármacos , Miócitos de Músculo Liso/fisiologia , Técnicas de Patch-Clamp , Peptídeos/farmacologia , Canal de Liberação de Cálcio do Receptor de Rianodina/fisiologia , Traqueia/citologia , Traqueia/fisiologia
15.
Pak J Pharm Sci ; 27(3 Suppl): 643-8, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24816695

RESUMO

The study focused on the change of microbial characteristics affected by Plumbum pollution with purple paddy soil in an incubation experiment. The results showed that low concentration of Plumbum had little effect on most of microbial amounts, biological activity and enzymatic activity. However, denitrifying activity was inhibited severely, and inhibition rate was up to 98%. Medium and high concentration of Plumbum significantly reduced the amounts and activity of all microorganisms and enzymatic activity, which increased with incubation time. Negative correlations were found between Plumbum concentrations and microbial amounts, biological activity and enzymatic activities except fungi and actinomyces. Thus they can be used to indicate the Plumbum pollution levels to some extent. LD(50) of denitrifying bacteria (DB) and ED50 of denitrifying activity were 852mg/kg and 33.5mg/kg. Across all test soil microbes, denitrifying bacteria was most sensitive to Plumbum pollution in purple paddy soil. Value of early warning showed that anaerobic cellulose-decomposing bacteria (ACDB) and actinomyces were also sensitive to Plumbum pollution. We concluded that denitrifying activity, actinomyces, ACDB or DB can be chosen as predictor of Plumbum contamination in purple paddy soil.


Assuntos
Bactérias/efeitos dos fármacos , Chumbo/toxicidade , Microbiologia do Solo , Poluentes do Solo/toxicidade , Bactérias/metabolismo , Desnitrificação , Solo/química
16.
Org Biomol Chem ; 7(1): 193-200, 2009 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-19081963

RESUMO

A series of N-acylhydrazones were synthesised and found to be "turn-on" fluorescent chemodosimeters for Cu(2+). Among the tested transition metal ions such as Cu(2+), Pb(2+), Zn(2+), Cd(2+), Hg(2+), and Ni(2+), a prominent fluorescence enhancement of up to 1000-fold was only observed for Cu(2+) in acetonitrile (CH(3)CN). This was indicated by an onset of unprecedented structured emission. Detailed experiments established that the highly Cu(2+) selective fluorescence enhancement resulted from an oxidative cyclization by Cu(2+)of the originally nonfluorescent N-acylhydrazones into highly fluorescent rigid 1,3,4-oxadiazoles, n-dope type blocks in optoelectronic materials. The chemodosimeters can be applied to sense Cu(2+) at nM levels in CH(3)CN and sub-microM levels in neutral aqueous environments, despite a slower response in the latter case. It is expected that these redox-based chemodosimeters might be of general applicability.

17.
J Org Chem ; 72(26): 9947-53, 2007 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-18020364

RESUMO

A series of salicylanilides (1a-h) bearing varied substituents at the 3'- or 4'-position of the anilino moiety (substituent = p-OCH3, p-CH3, m-CH3, H, p-Cl, m-Cl, p-CO2CH3, and p-CN) were synthesized. In acetonitrile all of the substituted salicylanilides 1a-h predominantly adopt the "closed-ring" conformation facilitated by a strong intramolecular OH...O=C hydrogen bond. In the presence of H2PO4-, the conformation of 1a-h was found to be modulated by the substituent. With our proposed proton-transfer fluorescence probing method, we were able to show that the conformation of 1a-f bearing a not highly electron-withdrawing substituent was switched to the "open-ring" form by H2PO4-, whereas 1h bearing a highly electron-withdrawing substituent, p-CN, remained in the "closed-ring" conformation. The significance of these findings for understanding, from a molecular structural point of view, the mechanism of salicylanilide-based inhibitors for inhibiting the protein tyrosine kinase epidermal growth factor receptor was discussed.


Assuntos
Inibidores de Proteínas Quinases/farmacologia , Salicilanilidas/química , Salicilanilidas/farmacologia , Acetonitrilas/química , Ânions/química , Ligação Competitiva/efeitos dos fármacos , Ligação de Hidrogênio , Espectroscopia de Ressonância Magnética/métodos , Conformação Molecular , Estrutura Molecular , Ácidos Fosfóricos/química , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/química , Salicilanilidas/síntese química , Relação Estrutura-Atividade
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