63 research outputs found
Synthesis and application of targeted molecular imaging agents for enhanced disease imaging and therapy
Dual fluorescent molecular substrates selectively report the activation, sustainability and reversibility of cellular PKB/Akt activity
Using a newly developed near-infrared (NIR) dye that fluoresces at two different wavelengths (dichromic fluorescence, DCF), we discovered a new fluorescent substrate for Akt, also known as protein kinase B, and a method to quantitatively report this enzyme\u27s activity in real time. Upon insulin activation of cellular Akt, the enzyme multi-phosphorylated a single serine residue of a diserine DCF substrate in a time-dependent manner, culminating in monophospho- to triphospho-serine products. The NIR DCF probe was highly selective for the Akt1 isoform, which was demonstrated using Akt1 knockout cells derived from MMTV-ErbB2 transgenic mice. The DCF mechanism provides unparalleled potential to assess the stimulation, sustainability, and reversibility of Akt activation longitudinally. Importantly, NIR fluorescence provides a pathway to translate findings from cells to living organisms, a condition that could eventually facilitate the use of these probes in humans
Binding of NIR-conPK and NIR-6T to Astrocytomas and Microglial Cells: Evidence for a Protein Related to TSPO
PK 11195 and DAA1106 bind with high-affinity to the translocator protein (TSPO, formerly known as the peripheral benzodiazepine receptor). TSPO expression in glial cells increases in response to cytokines and pathological stimuli. Accordingly, [11C]-PK 11195 and [11C]-DAA1106 are recognized molecular imaging (MI) agents capable of monitoring changes in TSPO expression occurring in vivo and in response to various neuropathologies
The 5p15.33 Locus Is Associated with Risk of Lung Adenocarcinoma in Never-Smoking Females in Asia
Genome-wide association studies of lung cancer reported in populations of European background have identified three regions on chromosomes 5p15.33, 6p21.33, and 15q25 that have achieved genome-wide significance with p-values of 10−7 or lower. These studies have been performed primarily in cigarette smokers, raising the possibility that the observed associations could be related to tobacco use, lung carcinogenesis, or both. Since most women in Asia do not smoke, we conducted a genome-wide association study of lung adenocarcinoma in never-smoking females (584 cases, 585 controls) among Han Chinese in Taiwan and found that the most significant association was for rs2736100 on chromosome 5p15.33 (p = 1.30×10−11). This finding was independently replicated in seven studies from East Asia totaling 1,164 lung adenocarcinomas and 1,736 controls (p = 5.38×10−11). A pooled analysis achieved genome-wide significance for rs2736100. This SNP marker localizes to the CLPTM1L-TERT locus on chromosome 5p15.33 (p = 2.60×10−20, allelic risk = 1.54, 95% Confidence Interval (CI) 1.41–1.68). Risks for heterozygote and homozygote carriers of the minor allele were 1.62 (95% CI; 1.40–1.87), and 2.35 (95% CI: 1.95–2.83), respectively. In summary, our results show that genetic variation in the CLPTM1L-TERT locus of chromosome 5p15.33 is directly associated with the risk of lung cancer, most notably adenocarcinoma
Synthesis and application of targeted molecular imaging agents for enhanced disease imaging and therapy
Targeted zwitterionic near infrared fluorescent probe for improved imaging of type 2 cannabinoid receptors
In Vivo Type 2 Cannabinoid Receptor-Targeted Tumor Optical Imaging Using a Near Infrared Fluorescent Probe
The
type 2 cannabinoid receptor (CB<sub>2</sub>R) plays a vital
role in carcinogenesis and progression and is emerging as a therapeutic
target for cancers. However, the exact role of CB<sub>2</sub>R in
cancer progression and therapy remains unclear. This has driven the
increasing efforts to study CB<sub>2</sub>R and cancers using molecular
imaging tools. In addition, many types of cancers overexpress CB<sub>2</sub>R, and the expression levels of CB<sub>2</sub>R appear to
be associated with tumor aggressiveness. Such upregulation of the
receptor in cancer cells provides opportunities for CB<sub>2</sub>R-targeted imaging with high contrast and for therapy with low side
effects. In the present study, we report the first in vivo tumor-targeted
optical imaging using a novel CB<sub>2</sub>R-targeted near-infrared
probe. In vitro cell fluorescent imaging and a competitive binding
assay indicated specific binding of NIR760-mbc94 to CB<sub>2</sub>R in CB<sub>2</sub>-mid delayed brain tumor (DBT) cells. NIR760-mbc94
also preferentially labeled CB<sub>2</sub>-mid DBT tumors in vivo,
with a 3.7-fold tumor-to-normal contrast enhancement at 72 h postinjection,
whereas the fluorescence signal from the tumors of the mice treated
with NIR760 free dye was nearly at the background level at the same
time point. SR144528, a CB<sub>2</sub>R competitor, significantly
inhibited tumor uptake of NIR760-mbc94, indicating that NIR760-mbc94
binds to CB<sub>2</sub>R specifically. In summary, NIR760-mbc94 specifically
binds to CB<sub>2</sub>R in vitro and in vivo and appears to be a
promising molecular tool that may have great potential for use in
diagnostic imaging of CB<sub>2</sub>R-positive cancers and therapeutic
monitoring as well as in elucidating the role of CB<sub>2</sub>R in
cancer progression and therapy
Perfluorocarbon nanoemulsions with fluorescent, colloidal and magnetic properties
Bimodal imaging agents that combine magnetic resonance imaging (MRI) and nearinfrared (NIR) imaging formulated as nanoemulsions became increasingly popular for imaging inflammation in vivo. Quality of in vivo imaging using nanoemulsions is directly dependent on their integrity and stability. Here we report the design of nanoemulsions for bimodal imaging, where both photostability and colloidal stability are equally addressed. A highly chemically and photo stable quaterrylenediimide dye was introduced into perfluoro-15-crown-5 ether (PCE) nanoemulsions. The nanoemulsions were prepared with PCE and Miglyol 812N mixed at 1:1 v/v ratio as internal phase stabilized by non-ionic surfactants. Data shows exceptional colloidal stability demonstrated as unchanged droplet size (~130 nm) and polydispersity (\u3c0.15) after 182 days follow up at both 4 and 25 °C. Nanoemulsions also sustained the exposure to mechanical and temperature stress, and prolonged exposure to light without changes in droplet size, 19F signal or fluorescence signal. No toxicity was observed in vitro in model inflammatory cells upon 24 h exposure while confocal microscopy showed that nanoemulsions droplets accumulated in the cytoplasm. Overall, our data demonstrates that design of bimodal imaging agents requires consideration of stability of each imaging component and that of the nanosystem as a whole to achieve excellent imaging performance. © 2014 Elsevier Ltd
Solvothermal synthesis of La-based metal-organic frameworks and their color-tunable photoluminescence properties
A series of La-based metal-organic frameworks (La-MOFs) phosphors have been successfully synthesized by a facile solvothermal method without assistance of any surfactant or template. The results show that the ethanol volume ratio is important to obtain adjustable shape and size of La-MOFs in the synthesis process. The obtained samples possess flake-like architectures with about 3-5 mu m in length. Under UV excitation, all the La-MOFs:Tb3+, Eu3+ phosphors exhibit the characteristic emissions of Tb3+ and Eu3+. Moreover, the emitting color of the as-obtained products can be acquired from green, green-yellow, yellow, yellow-orange, orange, to red owing to the efficient energy transfer (ET) between Tb3+ and Eu(3+)ions. The ET efficiency of the samples was calculated, and the maximum was found about 96.84%. Furthermore, the dipole-quadrupole interaction has been reasonable proved by the energy transfer between Tb3+ and Eu3+. These results indicated that La-MOFs:Tb3+, Eu3+ might be as a novel potential candidate as phosphors for displays and lightings
Synthesis and spectroscopy of near infrared fluorescent dyes for investigating dichromic fluorescence
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