title: Development of a real-time imaging system for hypoxic cell apoptosis.
abstract: Hypoxic regions within the tumor form due to imbalances between cell proliferation and angiogenesis; specifically, temporary closure or a reduced flow due to abnormal vasculature. They create environments where cancer cells acquire resistance to therapies. Therefore, the development of therapeutic approaches targeting the hypoxic cells is one of the most crucial challenges for cancer regression. Screening potential candidates for effective diagnostic modalities even under a hypoxic environment would be an important first step. In this study, we describe the development of a real-time imaging system to monitor hypoxic cell apoptosis for such screening. The imaging system is composed of a cyclic luciferase (luc) gene under the control of an improved hypoxic-responsive promoter. The cyclic luc gene product works as a caspase-3 (cas-3) monitor as it gains luc activity in response to cas-3 activation. The promoter composed of six hypoxic responsible elements and the CMV IE1 core promoter drives the effective expression of the cyclic luc gene in hypoxic conditions, enhancing hypoxic cell apoptosis visualization. We also confirmed real-time imaging of hypoxic cell apoptosis in the spheroid, which shares properties with the tumor. Thus, this constructed system could be a powerful tool for the development of effective anticancer diagnostic modalities.
authors.affiliation: School of Allied Health Sciences, Kitasato University , Sagamihara, Kanagawa, Japan.
authors.forename: Go
authors.initials: G
authors.lastname: Kagiya
authors.affiliation: Department of Radiological Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama , Sugitani, Toyama, Japan.
authors.forename: Ryohei
authors.initials: R
authors.lastname: Ogawa
authors.affiliation: Innovation Center for Medical Redox Navigation, Kyushu University , Higashi-ku, Fukuoka, Japan.
authors.forename: Fuminori
authors.initials: F
authors.lastname: Hyodo
authors.affiliation: Division of Radiation Oncology, Chiba Cancer Center , Chiba, Chiba, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Yamashita
authors.affiliation: Department of Diagnostic Radiology, Kitasato University Hospital , Sagamihara, Kanagawa, Japan.
authors.forename: Mizuki
authors.initials: M
authors.lastname: Nakamura
authors.affiliation: Department of Diagnostic Radiology, Saitama Prefectural Cancer Center , Kitaadachi-gun, Saitama, Japan.
authors.forename: Ayumi
authors.initials: A
authors.lastname: Ishii
authors.affiliation: Graduate School of Medicine, Gunma University , Maebashi, Gunma, Japan.
authors.forename: Yukihiko
authors.initials: Y
authors.lastname: Sejimo
authors.affiliation: School of Allied Health Sciences, Kitasato University , Sagamihara, Kanagawa, Japan.
authors.forename: Shintaro
authors.initials: S
authors.lastname: Tominaga
authors.affiliation: Innovation Center for Medical Redox Navigation, Kyushu University , Higashi-ku, Fukuoka, Japan.
authors.forename: Masaharu
authors.initials: M
authors.lastname: Murata
authors.affiliation: Biology Group, The Wakasa Wan Energy Research Center, Nagatani , Tsuruga, Fukui, Japan.
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Tanaka
authors.affiliation: Biology Group, The Wakasa Wan Energy Research Center, Nagatani , Tsuruga, Fukui, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Hatashita