Analysis of oxidative stress response in clinically relevant radioresistant cells

Kazuo Tomita; Yoshikazu Kuwahara; Yuko Takashi; Sayuri Yamanishi; Hideki Nabika; Koh-ich Tanaka; Junichi Kitanaka; Nobue Kitanaka; Motohiko Takemura; Nobuyoshi Nishiyama; Shouichi Miyawaki; Manabu Fukumoto; Yoshihiro Nishitani; Akihiro Kurimasa; Tomoaki Sato

doi:10.1254/jpssuppl.WCP2018.0_PO3-7-32

WCP2018 (The 18th World Congress of Basic and Clinical Pharmacology)

Session ID : WCP2018_PO3-7-32

DOI https://doi.org/10.1254/jpssuppl.WCP2018.0_PO3-7-32

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Host: The Japanese Pharmacological Society, The Japanese Society of Clinical Pharmacology

Name : WCP2018 (18th World Congress of Basic and Clinical Pharmacology)

Location : Kyoto

Date : July 01, 2018 - July 06, 2018

Poster session

Analysis of oxidative stress response in clinically relevant radioresistant cells

Kazuo Tomita, Yoshikazu Kuwahara, Yuko Takashi, Sayuri Yamanishi, Hideki Nabika, Koh-ich Tanaka, Junichi Kitanaka, Nobue Kitanaka, Motohiko Takemura, Nobuyoshi Nishiyama, Shouichi Miyawaki, Manabu Fukumoto, Yoshihiro Nishitani, Akihiro Kurimasa, Tomoaki Sato

Author information

Kazuo Tomita
Applied Pharmacology, Graduate School of Medical and Dental Sciences, Kagoshima University, Japan
Division of Pharmacology, Department of Pharmacy, School of Pharmacy, Hyogo University of Health Sciences, Japan
Yoshikazu Kuwahara
Applied Pharmacology, Graduate School of Medical and Dental Sciences, Kagoshima University, Japan
Radiation Biology and Medicine, Faculty of Medicine, Tohoku Medical and Pharmaceutical University, Japan
Yuko Takashi
Applied Pharmacology, Graduate School of Medical and Dental Sciences, Kagoshima University, Japan
Restorative Dentistry and Endodontology, Graduate School of Medical and Dental Sciences, Kagoshima University, Japan
Sayuri Yamanishi
Applied Pharmacology, Graduate School of Medical and Dental Sciences, Kagoshima University, Japan
Orthodontics and Dentofacial Orthpedics, Graduate School of Medical and Dental Sciences, Kagoshima University, Japan
Hideki Nabika
Material and Biological Chemistry, Faculty of Science, Yamagata University, Japan
Koh-ich Tanaka
Division of Pharmacology, Department of Pharmacy, School of Pharmacy, Hyogo University of Health Sciences, Japan
Junichi Kitanaka
Department of Pharmacology, Hyogo College of Medicine, Japan
Nobue Kitanaka
Department of Pharmacology, Hyogo College of Medicine, Japan
Motohiko Takemura
Department of Pharmacology, Hyogo College of Medicine, Japan
Nobuyoshi Nishiyama
Division of Pharmacology, Department of Pharmacy, School of Pharmacy, Hyogo University of Health Sciences, Japan
Shouichi Miyawaki
Orthodontics and Dentofacial Orthpedics, Graduate School of Medical and Dental Sciences, Kagoshima University, Japan
Manabu Fukumoto
Department of Molecular Pathology, Tokyo Medical University, Japan
Yoshihiro Nishitani
Restorative Dentistry and Endodontology, Graduate School of Medical and Dental Sciences, Kagoshima University, Japan
Akihiro Kurimasa
Radiation Biology and Medicine, Faculty of Medicine, Tohoku Medical and Pharmaceutical University, Japan
Tomoaki Sato
Applied Pharmacology, Graduate School of Medical and Dental Sciences, Kagoshima University, Japan

Keywords: Clinically Relevant Radioresistant (CRR) Cells, Hydrogen Peroxide, Plasma membrane

CONFERENCE PROCEEDINGS OPEN ACCESS

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Abstract

Radiation therapy is one of the choices to treat malignant tumors. Although radiation therapy has been established as an excellent local treatment for malignant tumors, existence of radiation resistant cell is a major problem to overcome. To reveal radioresistant mechanism, we investigated using clinically relevant radioresistant (CRR) cells that had been obtained by exposing to 2 Gy/day X-rays for more than 30 days. CRR cells show not only radioresistance but also resistant to anticancer drug docetaxel. CRR cells also show low frequency of DNA double strand breaks, low mitochondrial membrane potential and produce little amount of reactive oxygen species (ROS). However, the molecular mechanism to obtain radio-resistant is not clear. So, we try to reveal the resistant ability to other oxidative stress such as hydrogen peroxide (H₂O₂). First, we investigated the resistance of CRR cells against H₂O₂ using WST assay. As a result, these cells showed resistant to H₂O₂. Next, we examined gene expression and enzyme activity of catalase that is H₂O₂ catabolic enzyme. Catalase expression was up-regulated in CRR cells. However, catalase enzyme activity was down-regulated. We also investigated mitochondrial DNA (mtDNA) copy number. It was shown that the mtDNA copy number was decreased in CRR cells. In addition, the amount of ATP, ATPase gene expressions and plasma membrane potential were investigated in CRR cells. It was shown that the amount of ATP decreased, ATPase gene expressions were up regulated and plasma membrane potential were low in CRR cells. Furthermore, increase of internal H₂O₂ amount and lipid peroxidation was investigated. As a result, increase of internal H₂O₂ amount and lipid peroxidation were seen in parental cells 2h after H₂O₂ administration. On the other hand, increase of internal H₂O₂ amount and lipid peroxidation were not seen in CRR cells 2h after H₂O₂ administration. These results suggest that the decrease of cell response through plasma membrane component is the main factor rather than internal oxidative stress scavenging enzyme activity to obtain resistance against oxidative stress in CRR cells.

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