title: Inhibition of Regulatory Volume Decrease Enhances the Cytocidal Effect of Hypotonic Shock in Hepatocellular Carcinoma.
abstract: Background : Hypotonic shock induces cytocidal effects through cell rupture, and cancer therapy based on this mechanism has been clinically administered to hepatocellular carcinoma patients. We herein investigated the effectiveness of hypotonic shock combined with the inhibition of regulatory volume decrease as cancer therapy for hepatocellular carcinoma. Methods : Morphological changes in human hepatocellular carcinoma cell lines were observed under a differential interference contrast microscope connected to a high-speed digital video camera. Cell volume changes under hypotonic shock with or without chloride, potassium, or water channel blockers were observed using a high-resolution flow cytometer. In order to investigate cytocidal effects, the number of surviving cells was compared after exposure to hypotonic solution with and without each channel blocker (re-incubation experiment). Results : Video recordings showed that cells exposed to distilled water rapidly swelled and then ruptured. Cell volume measurements revealed regulatory volume decrease under mild hypotonic shock, whereas severe hypotonic shock increased the number of broken fragments as a result of cell rupture. Moreover, regulatory volume decrease was inhibited in cells treated with each channel blocker. Re-incubation experiments showed the cytocidal effects of hypotonic shock in cells exposed to hypotonic solution, and additional treatments with each channel blocker enhanced these effects. Conclusion : The inhibition of regulatory volume decrease with chloride, potassium, or water channel blockers may enhance the cytocidal effects of hypotonic shock in hepatocellular carcinoma. Hypotonic shock combined with the inhibition of regulatory volume decrease was a more effective therapy than hypotonic shock alone.
authors.affiliation: 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan;
authors.forename: Michihiro
authors.initials: M
authors.lastname: Kudou
authors.affiliation: 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan;
authors.forename: Atsushi
authors.initials: A
authors.lastname: Shiozaki
authors.affiliation: 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan;
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Kosuga
authors.affiliation: 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan;
authors.forename: Daisuke
authors.initials: D
authors.lastname: Ichikawa
authors.affiliation: 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan;
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Konishi
authors.affiliation: 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan;
authors.forename: Ryo
authors.initials: R
authors.lastname: Morimura
authors.affiliation: 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan;
authors.forename: Shuhei
authors.initials: S
authors.lastname: Komatsu
authors.affiliation: 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan;
authors.forename: Hisashi
authors.initials: H
authors.lastname: Ikoma
authors.affiliation: 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan;
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Fujiwara
authors.affiliation: 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan;
authors.forename: Kazuma
authors.initials: K
authors.lastname: Okamoto
authors.affiliation: 2. Departments of Molecular Cell Physiology and Bio-Ionomics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan;
authors.forename: Shigekuni
authors.initials: S
authors.lastname: Hosogi
authors.affiliation: 2. Departments of Molecular Cell Physiology and Bio-Ionomics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan;
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakahari
authors.affiliation: 2. Departments of Molecular Cell Physiology and Bio-Ionomics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan;; 3. Japan Institute for Food Education and Health, Heian Jogakuin (St. Agnes') University, Kyoto, 602-8013, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Marunaka
authors.affiliation: 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan;
authors.forename: Eigo
authors.initials: E
authors.lastname: Otsuji
keywords: Hepatocellular carcinoma; Regulatory volume decrease; chloride ion transport.; hypotonic shock; potassium ion transport