The identification of CUL3-SPOP and CUL3-PLZF target substrates for therapeutic targets in prostate cancer cells

Research Project

Project/Area Number	17K11142
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Research Field	Urology
Research Institution	Ehime University
Principal Investigator	Kikugawa Tadahiko 愛媛大学, 医学系研究科, 准教授 (70444734)
Co-Investigator(Kenkyū-buntansha)	雑賀隆史愛媛大学, 医学系研究科, 教授 (10314676) 東山繁樹愛媛大学, プロテオサイエンスセンター, 教授 (60202272)
Project Period (FY)	2017-04-01 – 2020-03-31
Project Status	Completed (Fiscal Year 2019)
Budget Amount *help	¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000) Fiscal Year 2019: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000) Fiscal Year 2018: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000) Fiscal Year 2017: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Keywords	前立腺がん / ユビキチンリガーゼ / SPOP / 質量分析法 / AlphaScreen法 / 腫瘍学
Outline of Final Research Achievements	Prostate cancer (PC) is among the most common adult male malignancies. Accordingly, the establishment of successful therapy for PC is one of the most important medical issues in aging society. SPOP and PLZF serve as substrate receptors in CUL3-based ubiquitine-E3 ligase complexes, and their genes have been reported to be commonly mutated in PC. Whole features of CUL3-SPOP and CUL3-PLZF target substrates, however, are still unclear. Therefore, we identified their substrates by using a newly developed human 20K protein array/AlphaScreen system combined with mass analysis. We identified 124 molecules expressed in PC as substrates for CUL3-SPOP, and established a simultaneous quantification method for 101 molecules of them based on the SPOP-substrate QconCAT/selective reaction monitoring (SRM). We are also still undergoing the identification of CUL3-PLZF target substrates with the same strategy. Our findings would be useful for the establishment of novel therapeutic targets for PC.
Academic Significance and Societal Importance of the Research Achievements	本研究では、前立腺において、がん発症抑制に関与するCUL3-SPOPシステムとCUL3-PLZF複合体を解明し、これらが標的とする基質分子の全容及びその生体機能を明らかにすることで、前立腺がん細胞ではこれまで全く明らかにされていないCUL3依存的ながん抑制機構、ならびに、その基質でありがん治療標的になりうる分子を解明することが可能となる。新たな前立腺がんの治療戦略の開発が可能となり、臨床応用に向け弾みがつくものと大いに期待でき、その意義は大きい。