Non-carrier-mediated uptake of the mannosidase I inhibitor 1-deoxymannojirimycin by K562 erythroleukemic cells.
A 3H label was introduced at the C-1 position of the mannosidase I inhibitor 1-deoxymannojirimycin (dMM) by catalytic hydrogenolysis of benzyl-2,3-O-isopropylidene-5-N-benzyl-6-O-benzyl-alpha-D-mannofurano side with 3H2. 1-[3H]dMM as well as its precursor 1-[3H]2,3-O-isopropylidene-dMM had identical Rf as the nonradioactive compounds on TLC. Furthermore, alpha 1-antitrypsin secreted by HepG2 cells was modified indistinguishably by treatment of the cells with dMM and 1-[3H]dMM. Thus, 1-[3H]dMM had chemical and biological properties identical with authentic dMM. Uptake of [14C]mannose by K562 cells could be inhibited by glucose but not by the mannose analogue dMM. Thus, dMM does not enter the cell through hexose transporter(s). Uptake of 1-[3H]dMM by K562 cells could not be inhibited by increasing concentrations of nonradioactive dMM (from 1-32,000 microM), showing transport of dMM into cells through nonfacilitated diffusion. Furthermore, uptake of 1-[3H]dMM by K562 cells was observed at 0 degrees C.
Neefjes
J J
JJ
Netherlands Cancer Institute, Amsterdam.
Lindhout
J
J
Broxterman
H J
HJ
van der Marel
G A
GA
van Boom
J H
JH
Ploegh
H L
HL
D017485:1-Deoxynojirimycin; D001692:Biological Transport / Q000187:drug effects; D002460:Cell Line; D005944:Glucosamine / Q000031:analogs & derivatives / Q000378:metabolism; D005947:Glucose / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D004915:Leukemia, Erythroblastic, Acute; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive; D008358:Mannose / Q000378:metabolism; D008361:Mannosidases / Q000037:antagonists & inhibitors*; D014316:Tritium
D014316:Tritium; D017485:1-Deoxynojirimycin; D008361:Mannosidases; C046090:mannosyl-oligosaccharide 1,2-alpha-mannosidase; D005947:Glucose; D005944:Glucosamine; D008358:Mannose