Functional 1,3a,6a-triazapentalene scaffold: Design of fluorescent probes for kinesin spindle protein (KSP)

Sawada, Jun‐ichi; Osawa, Ayumi; Takeuchi, Tomoki; Kaneda, Masato; Oishi, Shinya; Fujii, Nobutaka; Asai, Akira; Tanino, Keiji; Namba, Kosuke

doi:10.1016/j.bmcl.2016.10.047

Cited by 22 publications

(19 citation statements)

References 19 publications

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“…We recently discovered that a 1,3a,6a-triazapentalene (TAP) (1) skeleton is a compact and highly fluorescent chromophore with the potential to overcome the molecular size problem (Fig. 2) 15 , and it has been applied to various fluorescent probes [16][17][18][19] . Interestingly, the fluorescence of the TAPs shifted to longer wavelengths along with the inductive effect of the 2substituents 15,[19][20][21][22][23][24] .…”

Section: Resultsmentioning

confidence: 99%

“…2) 15 , and it has been applied to various fluorescent probes [16][17][18][19] . Interestingly, the fluorescence of the TAPs shifted to longer wavelengths along with the inductive effect of the 2substituents 15,[19][20][21][22][23][24] . By exploiting this effect, we recently developed yellow and red fluorescent 1,3a,6a-triazapentalene derivatives that are relatively smaller than the conventional yellow and red fluorescent molecules, as shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

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Development of a 1,3a,6a-triazapentalene derivative as a compact and thiol-specific fluorescent labeling reagent

et al. 2020

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For the fluorescence imaging of biologically active small compounds, the development of compact fluorophores that do not perturb bioactivity is required. Here we report a compact derivative of fluorescent 1,3a,6a-triazapentalenes, 2-isobutenylcarbonyl-1,3a,6a-triazapentalene (TAP-VK1), as a fluorescent labeling reagent. The reaction of TAP-VK1 with various aliphatic thiols proceeds smoothly to afford the corresponding 1,4-adducts in high yields, and nucleophiles other than thiols do not react. After the addition of thiol groups in dichloromethane, the emission maximum of TAP-VK1 shifts to a shorter wavelength and the fluorescence intensity is substantially increased. The utility of TAP-VK1 as a compact fluorescent labeling reagent is clearly demonstrated by the labeling of Captopril, which is a small molecular drug for hypertension. The successful imaging of Captopril, one of the most compact drugs, in this study demonstrates the usefulness of compact fluorophores for mechanistic studies.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Development of a 1,3a,6a-triazapentalene derivative as a compact and thiol-specific fluorescent labeling reagent

et al. 2020

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“…Cell cycle synchronization was conducted using the double thymidine block method (Bostock et al, 1971). HeLa cells expressing fluorescent histone H2B (Sawada et al, 2016) or Plk1 (see Supplemental Material) were also maintained in the same manner. Before starting this study, we confirmed no contamination of mycoplasma in the cells using a MycoAlert Mycoplasma Detection Kit (Lonza, Basel, Switzerland).…”

Section: Methodsmentioning

confidence: 99%

“…Time-Lapse Microscopy. Synchronous HeLa cells expressing fluorescent histone H2B (Sawada et al, 2016) were seeded at 1.25 Â 10 5 cells per well in 400 ml of the medium on Laboratory-Tek II eight-well CC2 glass chamber slides (Nalge Nunc). After a 7-hour incubation at 37°C in a 5% CO 2 incubator, the culture medium was replaced with 400 ml of fresh medium containing PVHD121 or PVHD277 along with 50 mM HEPES (pH 7.4).…”

Section: Methodsmentioning

confidence: 99%

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Selective Inhibition of Spindle Microtubules by a Tubulin-Binding Quinazoline Derivative

et al. 2019

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In the research field of tubulin-binding agents for the development of anticancer agents, hidden targets are emerging as a problem in understanding the exact mechanisms of actions. The quinazoline derivative 1-(4-methoxyphenyl)-1-(quinazolin-4yl)ethan-1-ol (PVHD121) has anti-cell proliferative activity and inhibits tubulin polymerization by binding to the colchicine site of tubulin. However, the molecular mechanism of action of PVHD121 in cells remains unclear. Here, we demonstrate that PVHD121 delays mitotic entry and efficiently causes mitotic arrest with spindle checkpoint activation, leading to subsequent cell death. The dominant phenotype induced by PVHD121 was aberrant spindles with robust microtubules and unseparated centrosomes. The microtubules were radially distributed, and their ends appeared to adhere to kinetochores, and not to centrosomes. Extensive inhibition by high concentrations of PVHD121 eliminated all microtubules from cells. PVHD277 [1-(4-methoxyphenyl)-1-(2-morpholinoquinazolin-4-yl)ethan-1-ol], a PVHD121 derivative with fluorescence, tended to localize close to the centrosomes when cells prepared to enter mitosis. Our results show that PVHD121 is an antimitotic agent that selectively disturbs microtubule formation at centrosomes during mitosis. This antimitotic activity can be attributed to the targeting of centrosome maturation in addition to the interference with microtubule dynamics. Due to its unique bioactivity, PVHD121 is a potential tool for studying the molecular biology of mitosis and a potential lead compound for the development of anticancer agents. SIGNIFICANCE STATEMENT Many tubulin-binding agents have been developed as potential anticancer agents. The aim of this study was to understand the subcellular molecular actions of a quinazoline derivative tubulinbinding agent, 1-(4-methoxyphenyl)-1-(quinazolin-4-yl)ethan-1ol (PVHD121). As expected from its binding activity to tubulin, PVHD121 caused aberrant spindles and inhibited mitotic progression. However, in addition to tubulin, PVHD121 also targeted an unexpected biomolecule involved in centrosome maturation. Due to targeting the biomolecule just before entering mitosis, PVHD121 preferentially inhibited centrosome-derived microtubules rather than chromosome-derived microtubules during spindle formation. This study not only revealed the molecular action of PVHD121 in cells but also emphasized the importance of considering possible tubulin-independent effects of tubulinbinding agents via hidden targeted biomolecules for future use.

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Privileged Structures in Drug Discovery

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Functional 1,3a,6a-triazapentalene scaffold: Design of fluorescent probes for kinesin spindle protein (KSP)

Cited by 22 publications

References 19 publications

Development of a 1,3a,6a-triazapentalene derivative as a compact and thiol-specific fluorescent labeling reagent

Development of a 1,3a,6a-triazapentalene derivative as a compact and thiol-specific fluorescent labeling reagent

Selective Inhibition of Spindle Microtubules by a Tubulin-Binding Quinazoline Derivative

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