Annual Report 2023

Laboratory of Molecular Genetics

Haruna Takeda, Kotomi Sato

Introduction

 Our laboratory focuses on colorectal cancer (CRC), using in vivo transposon screening and CRISPR-Cas9 to elucidate the molecular mechanisms of malignant progression and identify therapeutic targets. Since a high-fat diet and chronic inflammation increase the risk of cancer development and progression, in vivo screening using a high-fat diet mice and colitis mice are used to identify cancer-related genes. Furthermore, since gene mutations that activate the Wnt pathway are frequently observed in CRC, we perform a genome-wide CRISPR screen using CRC cell lines with these mutations to identify therapeutic targets.

Research Activities

 We performed transposon mutagenesis in mice fed with a high-fat diet and a control diet and obtained colon tumors. Analysis of the tumor genomes showed that the genes involved in the AMPK pathway were significantly more frequently mutated in high-fat diet-associated tumors. In addition, we found that signaling pathways involved in energy metabolism were activated in the colon epithelial cells of high-fat diet-fed mice, indicating that the gene expression profile of colon epithelial cells may affect cancer development.

 We performed a genome-wide CRISPR screen to identify therapeutic targets for CRC and obtained 59 candidate genes. We were able to extract one candidate gene through functional validation. Functional validation using another experimental system is currently ongoing.

Education

 We trained five students from Kitasato University, Hoshi University, and The University of Electro-Communications.

Future Prospects

 We will analyze the genes involved in high-fat diet-related tumor development using genetically engineered mice to elucidate the molecular mechanisms. In addition, functional validation of the genes identified as therapeutic targets for CRC will be conducted to obtain in vivo POC.

List of papers published in 2023

Journal

1. Iida N, Muranaka Y, Park JW, Sekine S, Copeland NG, Jenkins NA, Shiraishi Y, Oshima M, Takeda H. Sleeping Beauty transposon mutagenesis in mouse intestinal organoids identifies genes involved in tumor progression and metastasis. Cancer gene therapy, 31:527-536, 2024

2. Shimomura K, Hattori N, Iida N, Muranaka Y, Sato K, Shiraishi Y, Arai Y, Hama N, Shibata T, Narushima D, Kato M, Takamaru H, Okamoto K, Takeda H. Sleeping Beauty transposon mutagenesis identified genes and pathways involved in inflammation-associated colon tumor development. Nature communications, 14:6514, 2023