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A fluorescent probe targeting the ERBB2 receptor tyrosine was designed, synthesized and evaluated as reporter of ERBB2 dynamics in overexpressing BT474, i.e. Her2(+), cells. Two cyanoquinazoline ( CQ ) probes modeled after type-I ( CQ1 ) or active state and type-II ( CQ2 ) or inactive state inhibitors were designed and synthesized with extended π systems that impart binding-induced, turn-on fluorescence. Solution spectroscopy revealed that CQ1 exhibited attractive photophysical properties and displayed turn-on emission in the presence of purified, soluble ERBB2 kinase domain, while CQ2 was found to be non-emissive, likely due to quenching via a photoinduced electron transfer mechanism. Live cell imaging with CQ1 revealed that this probe targeted an intracellular population of ERBB2, which increased following treatment with type-I inhibitors, gefinitib and canertinib, but showed no response to type-II inhibitors. CQ1 thus provides a novel means of imaging the dynamic response of ERBB2(+) cells to kinase inhibitors. [ABSTRACT FROM AUTHOR]

Three new fluorescent molecular rotors were synthesized with the aim of using them as sensors to dose thymidine phosphorylase, one of the target enzymes of 5-fluorouracil, a potent chemotherapic drug largely used in the treatment of many solid tumors, that acts by hindering the metabolism of pyrimidines. 5-Fluorouracil has a very narrow therapeutic window, in fact, its optimal dosage is strictly related to the level of its target enzymes that vary significantly among patients, and it would be of the utmost importance to have an easy and fast method to detect and quantify them. The three molecular rotors developed as TP sensors differ in the length of the alkylic spacer joining the ligand unit, a thymine moiety, and the fluorescent molecular rotor, a [4-(1-dimethylamino)phenyl]-pyridinium bromide. Their ability to trigger an optical signal upon the interaction with thymidine phosphorylase was investigated by fluorescent measurements. [ABSTRACT FROM AUTHOR]

In this study, a new biodegradable cross-linker agent based on fructose was reported for fabrication of brain targeted molecularly imprinted polymer (MIP). The applied strategy for targeting drug delivery was based on two mechanisms. Firstly, the magnetic structure of prepared MIP which facilitates the aggregation of carrier near target tissue under magnetic field. Second, the tendency of brain cell to use the produced fructose during degradation of MIP as fuel. In synthesis procedure magnetic fluorescent multi core shell structure MIP was prepared via co-precipitation polymerization in the presence of olanzapine as template and fructose with double acts, as monomer and cross-linker. Various kinds of in vitro and in vivo experiments were carried out to indicate the considered properties of carrier. The obtained data confirmed the designed carrier olanzapine satisfactorily meet the requirement in brain drug delivery application. [ABSTRACT FROM AUTHOR]

Perivascular adipose tissue (PVAT) reduces vasoconstriction to norepinephrine (NE). A mechanism by which PVAT could function to reduce vascular contraction is by decreasing the amount of NE to which the vessel is exposed. PVATs from male Sprague-Dawley rats were used to test the hypothesis that PVAT has a NE uptake mechanism. NE was detected by HPLC in mesenteric PVAT and isolated adipocytes. Uptake of NE (10 μM) in mesenteric PVAT was reduced by the NE transporter (NET) inhibitor nisoxetine (1 μM, 73.68 ± 7.62%, all values reported as percentages of vehicle), the 5-hydroxytryptamine transporter (SERT) inhibitor citalopram (100 nM) with the organic cation transporter 3 (OCT3) inhibitor corticosterone (100 μM, 56.18 ± 5.21%), and the NET inhibitor desipramine (10 μM) with corticosterone (100 μM, 61.18 ± 6.82%). Aortic PVAT NE uptake was reduced by corticosterone (100 μM, 53.01 ± 10.96%). Confocal imaging of mesenteric PVAT stained with 4-[4-(dimethylamino)-styrl]-N-methylpyridinium iodide (ASP+), a fluorescent substrate of cationic transporters, detected ASP+ uptake into adipocytes. ASP+ (2 μM) uptake was reduced by citalopram (100 nM, 66.68 ± 6.43%), corticosterone (100 μM, 43.49 ± 10.17%), nisoxetine (100 nM, 84.12 ± 4.24%), citalopram with corticosterone (100 nM and 100 μM, respectively, 35.75 ± 4.21%), and desipramine with corticosterone (10 and 100 μM, respectively, 50.47 ± 5.78%). NET protein was not detected in mesenteric PVAT adipocytes. Expression of Slc22a3 (OCT3 gene) mRNA and protein in PVAT adipocytes was detected by RT-PCR and immunocytochemistry, respectively. These end points support the presence of a transporter-mediated NE uptake system within PVAT with a potential mediator being OCT3. [ABSTRACT FROM AUTHOR]

A new optical strategy to determine the binding modes (intercalation vs groove binding) of small fluorescent organic molecules with calf thymus DNA was developed using two-photon absorption (TPA) spectroscopy. Two-photon excited emission was utilized to investigate a series of fluorescent nuclear dyes. The results show that TPA cross-sections are able to differentiate the fine details between the DNA binding modes. Groove binding molecules exhibit an enhanced TPA cross-section due to the DNA electric field induced enhancement of the transition dipole moment, while intercalative binding molecules exhibit a decrease in the TPA cross-section. Remarkably, the TPA cross-section of 4,6-bis(4-(4-methylpiperazin-1-yl)phenyl) pyrimidine is significantly enhanced (13.6-fold) upon binding with DNA. The sensitivity of our TPA methodology is compared to circular dichroism spectroscopy. TPA demonstrates superior sensitivity by more than an order of magnitude at low DNA concentrations. This methodology can be utilized to probe DNA interactions with other external molecules such as proteins, enzymes, and drugs. [ABSTRACT FROM AUTHOR]

In this study, we report the efficient identification of proteins using (6-hydroxy-2-naphthyl)ethenyl pyridinium dyes ( HNEPs). These dyes exhibited characteristic fluorescence responses, showing enhanced fluorescence with a red shift in the case of bovine serum albumin. The nature of the interaction between the dye and the protein was examined using a combination of various spectroscopic techniques. A time-dependent density functional theory analysis supported the strong environment-dependent fluorescence emission properties of the dyes. The current investigation clearly demonstrates that a selective optical response HNEPs can find potential usefulness as bio-sensing probes. [ABSTRACT FROM AUTHOR]