Lanthanide complexes as fluorescent indicators for neutral sugars and cancer biomarkers.
Simple water-soluble lanthanum and europium complexes are effective at detecting neutral sugars as well as glycolipids and phospholipids. In solutions at physiologically relevant pH the fluorescent lanthanum complex binds neutral sugars with apparent binding constants comparable to those of arylboronic acids. Interference from commonly occurring anions is minimal. The europium complex detects sialic acid-containing gangliosides at pH 7.0 over an asialoganglioside. This selectivity is attributed, in large part, to the cooperative complexation of the oligosaccharide and sialic acid residues to the metal center, based on analogous prior studies. In MeOH, lysophosphatidic acid (LPA), a biomarker for several pathological conditions including ovarian cancer, is selectively detected by the europium complex. LPA is also detected via a fluorescence increase in human plasma samples. The 2-sn-OH moiety of LPA plays a key role in promoting binding to the metal center. Other molecules found in common brain ganglioside and phospholipid extracts do not interfere in the ganglioside or LPA fluorescence assays.
Alptürk
Onur
O
Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA.
Rusin
Oleksandr
O
Fakayode
Sayo O
SO
Wang
Weihua
W
Escobedo
Jorge O
JO
Warner
Isiah M
IM
Crowe
William E
WE
Král
Vladimir
V
Pruet
Jeff M
JM
Strongin
Robert M
RM
D014408:Biomarkers, Tumor / Q000032:analysis*; D002240:Carbohydrate Sequence; D005063:Europium / Q000737:chemistry*; D005260:Female; D005456:Fluorescent Dyes / Q000737:chemistry*; D005732:Gangliosides / Q000032:analysis*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007811:Lanthanum / Q000737:chemistry*; D008246:Lysophospholipids / Q000032:analysis; D000432:Methanol / Q000737:chemistry; D008969:Molecular Sequence Data; D009369:Neoplasms / Q000175:diagnosis; D010051:Ovarian Neoplasms / Q000175:diagnosis; D012459:Salicylates / Q000737:chemistry*
D014408:Biomarkers, Tumor; D005456:Fluorescent Dyes; D005732:Gangliosides; D008246:Lysophospholipids; D012459:Salicylates; C090416:salophen; D005063:Europium; D007811:Lanthanum; C032881:lysophosphatidic acid; D000432:Methanol