Clean operating margins in breast cancer surgery are important for preventing recurrence. However, the current methods for determining margins such as intraoperative frozen section analysis or ...imprint cytology are not satisfactory since they are time‐consuming and cause a burden on the patient and on hospitals with a limited accuracy. A “click‐to‐sense” probe is developed based on the detection of acrolein, which is a substance released by oxidatively stressed cancer cells and can be visualized under fluorescence microscopy. Using live breast tissues resected from breast cancer patients, it is demonstrated that this method can quickly, selectively, and sensitively differentiate cancer lesion from normal breast gland or benign proliferative lesions. Since acrolein is accumulated in all types of cancers, this method could be used to quickly assess the surgical margins in other types of cancer.
A “click‐to‐sense” acrolein probe allows the diagnosis of cancer morphology with high sensitivity and selectivity. The cancer lesion can be discriminated from normal breast gland by simply treating the live tissues from cancer patients with the “click‐to‐sense” acrolein probe.
Radiolabeled biomolecules with short half‐life times are of increasing importance for positron emission tomography (PET) imaging studies. Herein, we demonstrate an improved and generalized method for ...synthesizing a radiometal‐unsaturated aldehyde as a lysine‐labeling probe that can be easily conjugated into various biomolecules through the RIKEN click reaction. As a case study, 68Ga‐PET imaging of U87MG xenografted mice is demonstrated by using the 68Ga‐DOTA‐RGDyK peptide, which is selective to αVβ3 integrins.
In two clicks: An improved and generalized metal‐labeling protocol with the use of 68Ga is presented. Two click‐type reactions, that is, the RIKEN click reaction and the strain‐promoted click reaction, are used to prepare 68Ga‐DOTA‐cyclic RGD peptide, which is selective to αVβ3 integrins and is used as a probe for the positron emission tomography imaging of tumor‐implanted mice.
Acrolein, a highly toxic α,β-unsaturated aldehyde, has been a longstanding key biomarker associated with a range of disorders related to oxidative stresses. Currently available analytical methods ...rely on the indirect protocols, e.g., derivatization/HPLC or mAb detection of the lysine adducts. Consequently, developing new analytical tools for acrolein detection that are straightforward, cost-effective, selective, and preferably feasible using live cells remains a highly essential pursuit in the diagnosis and therapeutic treatment of oxidative stress-related diseases. We demonstrated that for the first time aryl azides can rapidly and selectively react with acrolein in a “click” manner to provide 4-formyl-1,2,3-triazolines and 4-formyl-1,2,3-triazoles, which represents an unexplored reactivity of aryl azides. When treating a fluorescently labeled phenyl azide with oxidatively stressed or smoking-associated cell models, these heterocyclic compounds could be selectively taken up by the cells and preferably localized at the endoplasmic reticulum (ER) and lysosome, leading to a new tool for both effectively detecting acrolein level and directly imaging live cells that are under stress. The detection method developed here is convenient: target cells may be treated with fluorescently labeled azides to enable the direct and efficient detection of acrolein in live system. The simple stuctures of the azide probes allows for functional groups other than fluorescent groups to be readily linked to aryl azides to image, examine, or target cells associated with oxidative stress processes. We developed a new method for detecting and imaging acrolein extracellularly released by cells in the context of oxidative stress processes or introduced via environmental exposure.
Acrolein, a highly toxic α, β-unsaturated aldehyde, occurs as pollutant in the environment (e.g., tobacco smoke and exhaust gas) and is ubiquitously generated in biosystems (e.g., the lipid ...peroxidation process and metabolism of polyamine or amino acids). High accumulation of acrolein in biosystems is often linked pathologically with several oxidative stress-related diseases, including cancer and Alzheimer's disease. Accordingly, acrolein holds great potential as a key biomarker in oxidative stress-related diseases, and direct measurement of acrolein in biological samples is important to provide information for diagnostic and therapeutic purposes. Recently, we have serendipitously discovered the unrecognized reactivity of phenyl azide to acrolein. Phenyl azide can rapidly and selectively react with acrolein in a "click" manner to provide 4-formyl-1,2,3-triazoline through 1,3-dipolar cycloaddition. We have successfully utilized the acrolein-azide click reaction as a simple but robust method for detecting and visualizing acrolein generated by live cells in the context of oxidative stress processes. In addition, we also serendipitously discovered novel cycloaddition reactions of N-alkyl-α,β-unsaturated imines derived from acrolein and biogenic amines (e.g., polyamines, norepinephrine, and sphingosine), to yield 8-membered cyclic compounds. We then examined the biological functions of the cyclic products and revealed for the first time their roles in the oxidative stress mechanism and inhibition of amyloid β(1-40) fibrillization.
We have shown that “Click-to-sense” (CTS) assay based on the visualization of cancer cells by fluorescence probe targeted for acrolein is useful for differentiating between the malignant and benign ...lesions of the breast. In the present study, we aimed to apply CTS assay to the examination of the simulated surgical margins, being compared with frozen section (FS) analysis.
The simulated surgical margin samples (n = 300) were obtained from 1 to 2 cm distant sites from the tumor margin in the mastectomy specimens of breast cancer patients, and divided into the training (n = 150) and validation (n = 150) set. The samples were subjected to CTS assay, subsequently to FS analysis and finally to permanent section (PS) analysis.
Diagnostic accuracy of the CTS assay and FS analysis was evaluated in the examination of the simulated surgical margin status finally determined by the PS analysis. In the training set, sensitivity, specificity, and accuracy was 89.3%, 98.4%, and 96.7% for the CTS assay and 89.3%, 98.4%, and 96.7% for the FS analysis. In the validation set, sensitivity, specificity, and accuracy was 93.3%, 98.3%, and 97.3% for the CTS assay, and 93.3%, 99.2%, and 98.0% for the FS analysis.
The CTS assay is as accurate as the FS analysis in the examination of the simulated surgical margins in breast cancer patients, and it seems to have a potential to replace the FS analysis for the intra-operative examination of surgical margins in breast-conserving surgery since it is less labor-intensive and more time-saving than the FS analysis.
•Click-to-sense (CTS) assay can visualize cancer cells in live tissue in short time.•It is important to examine surgical margin in breast conserving surgery.•CTS assay was applied to examination of simulated surgical margin samples.•CTS assay was as accurate as frozen section (FS) analysis.
We synthetically demonstrate that eight-membered heterocycles, namely, 2,6,9-triazabicyclo3.3.1nonanes and 1,5-diazacyclooctanes, are the exclusive products of the reaction of acrolein with ...biologically relevant amines
via
an imino4 + 4cycloaddition. These compounds are produced in much higher amounts and efficiencies than the acrolein biomarker in current use, 3-formyl-3,4-dehydropiperidine (FDP). Our results not only indicate that eight-membered heterocycles may potentially be used as new biomarkers, but also strongly suggest the involvement of these heterocycles in various important biological phenomena,
e.g.
, an acrolein-mediated mechanism underlying oxidative stress.
We synthetically demonstrate that eight-membered heterocycles are the exclusive products of the reaction of acrolein with biologically relevant amines
via
an imino4 + 4cycloaddition.
A general probe designed to induce a cascading sequence of reactions on a target protein was efficiently synthesized. The cascading reaction sequence involved (i) ligand-directed ...azaelectrocyclization with lysine and (ii) the autooxidation-induced release of a fluorescence quencher from the labeled protein. The probe was linked to a cyclic RGDyK peptide to enable the selective visualization of integrin αVβ3 on the surfaces of live cells.
Formal 4+4 reaction of the unsaturated benzyl- or allylimines, which is efficiently mediated by primary amine, provides the 2,6,9-triazabicyclo3.3.1nonane derivatives. Variously substituted homo- and ...hetero-coupling products are obtained in good to excellent yields by quite a simple procedure under mild conditions: by mixing the unsaturated aldehydes with the amines at room temperature.
Nucleotide-binding oligomerization domain protein 1 (Nod1) is an intracellular protein involved in recognition of the bacterial component peptidoglycan. This recognition event induces a host defense ...response to eliminate invading pathogens. The genetic variation of Nod1 has been linked to several inflammatory diseases and allergies, which are strongly affected by environmental factors. We have found that many of the bacteria that contain DAP-type peptidoglycan release Nod1 ligands into the environment. However, the structures of natural Nod1 ligands in the environment are not well understood. Herein, we report the isolation and structural elucidation of natural human Nod1 (hNod1) ligands from the Escherichia coli K-12 culture supernatant. The supernatant was fractionated with reversed-phase high performance liquid chromatography (RP-HPLC), resulting in the isolation of several hNod1 stimulatory fractions. Structural characterization studies demonstrated that the molecular structure of the most active fraction was the native hNod1 ligand GlcNAc-(β1–4)-(anhydro)MurNAc-l-Ala-γ-d-Glu-meso-DAP. We also found other peptidoglycan fragments using the 7-(diethylamino)coumarin-3-carbonyl labeling method to enhance sensitivity in mass spectroscopy studies. These results suggested that DAP-containing bacteria release certain hNod1 ligands to the environment, and these ligands would accumulate in the environment and regulate the immune system through Nod1.
The unsaturated ester aldehyde, (E)-3-alkoxycarbonyl-5-phenyl-2,4-dienal, was efficiently dimerized by applying the strain-promoted double-click reaction with ...sym-dibenzo-1,5-cyclooctadiene-3,7-diyne. The resulting dimerized probe was sequentially reacted first with one peptide molecule and then with a protein or the amino groups on the surface of a live cell through double azaelectrocyclization to achieve highly efficient bioconjugation.
PDF
