2019 Fiscal Year Annual Research Report
新規プローブライブラリーの構築に基づく大腸がん・胃がん検出蛍光プローブの開発
| Project/Area Number |
19F19339
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| Research Institution | The University of Tokyo |
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Principal Investigator |
浦野 泰照 東京大学, 大学院薬学系研究科(薬学部), 教授 (20292956)
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| Co-Investigator(Kenkyū-buntansha) |
KELLER SASCHA 東京大学, 薬学研究科(研究院), 外国人特別研究員
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| Project Period (FY) |
2019-11-08 – 2022-03-31
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| Keywords | Fluorescence / Cancer / Tumor / Rhodol / Spiro-cyclic / Computer-based |
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| Outline of Annual Research Achievements |
Despite all effort of screening available probes on stomach and colon cancer no good probe capable of selectively visualizing the cancerous tissue could be found. This project aims at finding suitable probes to detect said cancers by rational design of fluorescence probes based on a quantum chemical prediction of their intramolecular spiro-cyclization. Goals of the project include: (i) development of a computer based model to predict properties of novel fluorescent molecules, (ii) the synthesis of a library of amino-acid and sugar derivatives of novel Si-Rhodols that have promising properties; (iii) using those probes to visualize colon and stomach cancer as well as (iv) understanding of their overexpression of aminopeptidases and glycosidases in clinical specimens of cancerous colon and stomach tissue. Given the novel developed synthetic route which was even further enhanced fast and efficient synthesis of a huge variety of molecules is now possible. To develop a working model to predict the spiro-cyclization behavior of fluorescent probes, a few core structures were successfully synthesized. There are still differences of experimentally measured pKcycl-values and calculated pKcycl-values. The calculation model is still being fine-tuned until a closer match is achieved. The experimental values of a few compounds still seem suitable for the use as fluorescent probes for cancer. Preliminary data suggests that cancerous tissue could successfully be visualized in resected tumor samples.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
To calculate the important pKcycl-value of potential probes the free energy gap between the closed and the open form is estimated by a computational chemistry approach using the Gaussian Software. Thus, potential candidates inheriting the desired characteristics as for example the important pKcycl-value can be narrowed down. To fine-tune the computer-assisted prediction a variety of compounds were synthesized. During synthesis, the previously mentioned novel synthetic pathway was enhanced and now allows even more possibilities. A few promising compounds were synthesized, their characteristics were measured, and the pKcycl-value was compared to the calculated values. There is still a significant error but the right tendency to predict a molecules suitability can clearly be achieved. Modification of said molecules with sugar moieties showed an increase in fluorescence when administered to resected cancerous tissue. Control experiments of these candidates need to be conducted to ensure the viability of these preliminary results.
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| Strategy for Future Research Activity |
Finalizing the computer-based prediction of novel compounds. Derivatization of other synthesized suitable probes, with one of the known 500 amino acids (natural or non-natural amino acids), polypeptides or one of the vast numbers of sugar derivatives known in nature. First sugars and amino acids will be used which are already known to be over-expressed in cancerous tissue. The probes will first be tested with purified enzymes but also with cancerous cell lines to verify their behavior in vitro. Applicable probes will furthermore be tested in real cancerous specimens as well as mutant mice. Furthermore, the calculations could be expanded for the development of C-Rhodols or other congeners. After potential hits were found the responsible enzymes must be identified. This is possible by a diced electron gel (DAG) assay method developed in our lab. Furthermore, necessary control experiments must be conducted to exclude false conclusions. In case that the calculations for congeners of Si-Rhodols (C-, or P-Rhodols) are promising they will also be subject for the previously mentioned process, since small changes in a fluorophores molecular structure can have a big impact on their behavior and their localization in living cells. This might increase the chances to finally find suitable probes for the detection of colon and stomach cancer. When the experiments are finalized a publication of the found results is anticipated.
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Research Products
(2 results)
