title: A macrocyclic zinc(II) fluorophore as a detector of apoptosis.
abstract: Our originally designed dansylamidoethylcyclen 4 as a biomimetic Zn(2+)-selective fluorophore has been demonstrated to be a good detector of the apoptosis (induced by an anticancer agent, etoposide, and H(2)O(2)) in cancer cells such as HeLa and HL60 cells. The macrocyclic Zn(2+) ligand 4 (mostly as a deprotonated form) is cell-permeable to show weak fluorescence (emission at 550 nm), which forms a strong fluorescent 1:1 Zn(2+) complex 5 (emission at 530 nm) when Zn(2+) is incorporated into the cells by a zinc(II) ionophore pyrithione. Thus formed, Zn(2+) complex 5 is cell-impermeable and remains intact over a few hours. When apoptosis in HeLa or HL60 cells is artificially induced, 4 selectively and strongly stains apoptotic cells only at early stages, which was verified by using the conventional apoptosis detection probe annexin V-Cy3. Detection of the apoptotic cells by 4 was perhaps due to significantly increased free Zn(2+) flux at early stages of apoptosis. Apoptotic detection by 4 has been compared with a presently available Zn(2+) fluorophore, Zinquin 1. We present that 4 has advantages in detection of apoptosis over annexin V-Cy3 and Zinquin 1.
authors.affiliation: Faculty of Integrated Arts and Sciences, Hiroshima University, Kagamiyama 1-7-1, Higashi-Hiroshima 739-8521, Japan. ekimura@hiroshima-u.ac.jp
authors.forename: Eiichi
authors.initials: E
authors.lastname: Kimura
authors.forename: Shin
authors.initials: S
authors.lastname: Aoki
authors.forename: Emiko
authors.initials: E
authors.lastname: Kikuta
authors.forename: Tohru
authors.initials: T
authors.lastname: Koike
mesh_terms: D017209:Apoptosis; D015415:Biomarkers / Q000032:analysis; D003619:Dansyl Compounds / Q000737:chemistry; D005456:Fluorescent Dyes; D018922:HL-60 Cells; D006367:HeLa Cells; D006573:Heterocyclic Compounds, 1-Ring / Q000032:analysis / Q000737:chemistry*; D006801:Humans; D008968:Molecular Conformation; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000032:analysis / Q000737:chemistry*; D017967:Zinc Compounds / Q000032:analysis / Q000737:chemistry*
chemical_list: C473936:(1-(2-(5-(N,N-dimethylamino)naphthalenesulfonamido)ethyl)-1,4,7,10-tetraazacyclododecane)zinc(II); D015415:Biomarkers; D003619:Dansyl Compounds; D005456:Fluorescent Dyes; D006573:Heterocyclic Compounds, 1-Ring; D009942:Organometallic Compounds; D017967:Zinc Compounds