Identification of HLA-binding peptides of liver cnancer stem cells

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K17619
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 55020:Digestive surgery-related
• Research Institution: Yamaguchi University
• Principal Investigator: Kanekiyo Shinsuke 山口大学, 医学部, 特別医学研究員 (80555730)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 癌

Outline of Final Research Achievements

Comprehensive analysis by mass spectrometry (peptidome analysis) of peptides enriched by immunoprecipitation on a Sepharose bead column prepared with anti-HLA*A24:02 antibody was performed. The peptide sequences obtained were correlated with the mRNA expression encoding the protein containing the peptide, and the product with high mRNA expression was homologous to the consensus sequence. As a result of repeated experimental condition examinations, we succeeded in improving the peptide identity by using SCX columns for cation exchange. This allowed us to identify nearly 1,000 9-mer peptides with FDR<5%, most of which showed HLA-binding consensus sequences.

Free Research Field

消化器外科

Academic Significance and Societal Importance of the Research Achievements

がん細胞上でのHLA拘束ペプチドの配列同定は、オーダーメイド癌免疫療法の実現に向けて学術的・社会的に意義がある。本研究によって、peptideome解析 (がん組織と抗HLA抗体を用いた免疫沈降物の質量分析) の感度を向上させることができた。得られたペプチド配列を検討した結果、HLA拘束ペプチドはコンセンサス配列との相同性を示し、元となるタンパクをコードするmRNAレベルでは高い発現を示した。これらの結果から、プロテオミクスではなく次世代シーケンサーを用いた解析データのみでも、個々の症例に応じたHLA拘束ペプチドの配列を予測できることが示唆された。