title: An echo-contrast agent, Levovist, lowers the ultrasound intensity required to induce apoptosis of human leukemia cells.
abstract: To verify the effect of echo-contrast agent (ECA) on apoptosis induced by ultrasound, leukemia cell lines (Jurkat, Molt-4 and U937) were sonicated at intensities previously shown to induce optimal apoptosis with or without Levovist, an ECA. The results showed that loss of viability and apoptosis can be induced in all three cell lines, apoptosis highest with Molt-4, based on viability and DNA fragmentation assay. Such finding was supported by corresponding increase of cells with low mitochondrial membrane potential, high superoxide production, increased intracellular calcium concentration, and phosphorylation of histone H2AX after sonication. Optimal ultrasound condition was 0.3W/cm(2), 1MHz, 10% duty factor pulsed at 100Hz; but in the presence of Levovist, an apparent shift of cell killing induction was observed at 0.2W/cm(2). While these results further confirmed previous findings on ultrasound-induced apoptosis, they also suggest that use of an enhancing factor, such as addition of ECA, may be useful in cancer therapy when a much lower intensity is desired.
authors.affiliation: First Department of Surgery, Faculty of Medicine, Toyama Medical and Pharmaceutical University, Toyama 930-0194, Japan.
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Ando
authors.forename: Loreto B
authors.initials: LB
authors.lastname: Feril
authors.forename: Takashi
authors.initials: T
authors.lastname: Kondo
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Tabuchi
authors.forename: Ryohei
authors.initials: R
authors.lastname: Ogawa
authors.forename: Qing-Li
authors.initials: QL
authors.lastname: Zhao
authors.forename: Zheng-Guo
authors.initials: ZG
authors.lastname: Cui
authors.forename: Shin-Ichiro
authors.initials: S
authors.lastname: Umemura
authors.forename: Hideki
authors.initials: H
authors.lastname: Yoshikawa
authors.forename: Takuro
authors.initials: T
authors.lastname: Misaki
mesh_terms: D017209:Apoptosis; D002118:Calcium / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival; D003287:Contrast Media / Q000494:pharmacology*; D053938:DNA Fragmentation; D006657:Histones / Q000378:metabolism; D006801:Humans; D019169:Jurkat Cells; D007938:Leukemia / Q000473:pathology* / Q000628:therapy*; D008564:Membrane Potentials; D010766:Phosphorylation; D011134:Polysaccharides / Q000494:pharmacology*; D013481:Superoxides / Q000378:metabolism; D014464:Ultrasonic Therapy / Q000379:methods*
chemical_list: D003287:Contrast Media; C468783:H2AX protein, human; D006657:Histones; D011134:Polysaccharides; D013481:Superoxides; C059891:SHU 508; D002118:Calcium