| 研究課題/領域番号 |
19K19220
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| 研究機関 | 北海道大学 |
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研究代表者 |
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| 研究期間 (年度) |
2019-04-01 – 2021-03-31
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| キーワード | Tumor endothelial cell / Tumor angiogenesis / Glutamine metabolism / Glutaminolysis / Amino acid transporters |
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| 研究実績の概要 |
Tumor and normal endothelial cells were successfully isolated, characterized by gene expression analysis and cultured. Using metabolomics, we have compared the metabolome of the tumor and normal endothelial cells after exposing the cells to C13-labelled glutamine. We analyzed the metabolome of the cells (intracellularly) and metabolites released into the culture media (extracellular). It was found that the metabolites and end products of the glutaminolysis pathway in the two cells are different. Normal endothelial cells converted glutamine primarily to GABA whereas tumor endothelial cells produced more glutamate, asparagine, and aspartate from glutamine
We have recruited key enzymes of the glutaminolysis pathway and some amino acid transporters involved in transporting metabolites of the glutamine metabolism pathway for further analysis. We used siRNA and drugs to target these enzymes and transports and measured their effects on endothelial cell proliferation.
Pharmacological inhibition of one of the transporters significantly inhibited tumor endothelial cell proliferation with minimal impact on normal endothelial cells. Using siRNA against the key enzymes also exerted some inhibitory actions on the proliferation of all endothelial cells.
Since glutamine metabolism contributes to the tricarboxylic acid cycle in the mitochondria, the study is currently focusing on tumor endothelial cell mitochondria activity and processes as well. Analysis to compare mitochondria properties in tumor and normal endothelial cells are on-going.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
It was have found that tumor endothelial cells produce a unique set of metabolites (which played a role and rapid cell proliferation), which can, therefore, support tumor growth. However, due to the endothelial cell population (2%) within the tumor as compared to other stromal cells like fibroblast (30% - 60%), it would not be very feasible to analyze their effects in vivo without interference from metabolites in other cells.
We sort other ways of exploiting tumor endothelial cell glutamine metabolism to target tumor angiogenesis specifically. Our current plans aim at destroying the tumor angiogenesis, which will affect the role of tumor blood vessels to supply nutrients and dispose of waste.
The research is progressing with the focus on the roles of the accumulated metabolites within the tumor endothelial cells. For example, considering the accumulated levels of glutamate in tumor endothelial cells, specific amino acid transporters have been recruited for further studies.
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| 今後の研究の推進方策 |
1.In vitro analysis to determine gene and protein expressions of target amino acid transporters and enzymes involved in reactive oxygen species regulation along the glutamine metabolism pathway.
2.In vivo analysis of tumor growth and angiogenesis through targeting glutamine metabolism pathway metabolites involved in reactive oxygen species production and regulation.
3.Compare tumor and normal endothelial cell mitochondria properties. Followed by the evaluation of the mitochondrial metabolic activity, particularly oxygen consumption and ATP production, and its importance for tumor endothelial cell function.
4.In vivo targeting of tumor endothelial cell mitochondria using a mitochondria-specific nanodevice as a new therapeutic strategy for cancer antiangiogenesis treatment
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| 次年度使用額が生じた理由 |
The grant will be essential to further the research work based on the data achieved this far because of the following reasons.
There is a need to purchase new siRNAs and drugs to confirm current in vitro observations. Currently, plans are being made for in vivo experiments, and nude mice will be bought for that purpose. Other tumor models, apart from the current human xenograft model, will be tested to confirm the observations in different types of tumors, which would require additional mice.
Also, to target tumor angiogenesis with nanoparticles, designing of these particles may incur costs after completion of the on-going preliminary experiments.
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