Relationship between internalization kinetics and cytotoxicity of mistletoe lectin I to L1210 leukaemia cells.
We have taken two different approaches to the study of the entry of mistletoe lectin I (MLI) into murine L1210 leukaemia cells. As detected by cellular protein synthesis and DNA synthesis inhibition, the lectin was cytotoxic to L1210 leukaemia cells. Inhibition of [3H]leucine and [3H]thymidine incorporation into L1210 cells by MLI was found dose dependent in a concentration range from 10(-16) to 10(-12) mol/ml. The kinetics of cellular protein synthesis inhibition by MLI was concentration dependent, too. Using preembedding electron microscopy, the binding and intracellular routing of the gold-labelled lectin (MLI.Au15) were studied. MLI was internalized into L1210 leukaemia cells by two different pathways: via coated pits to coated vesicles and via long enclosed invaginations of the plasma membrane.
Walzel
H
H
Department of Biochemistry, Wilhelm Pieck University, Rostock.
Jonas
L
L
Rosin
T
T
Brock
J
J
D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000493:pharmacokinetics; D004705:Endocytosis; D007930:Leucine / Q000378:metabolism; D007939:Leukemia L1210 / Q000188:drug therapy* / Q000378:metabolism; D051379:Mice; D008811:Mice, Inbred DBA; D028321:Plant Preparations; D010940:Plant Proteins; D014176:Protein Biosynthesis / Q000187:drug effects; D054790:Ribosome Inactivating Proteins, Type 2; D013936:Thymidine / Q000378:metabolism; D014118:Toxins, Biological / Q000493:pharmacokinetics* / Q000494:pharmacology*; D014316:Tritium; D014407:Tumor Cells, Cultured
D000972:Antineoplastic Agents, Phytogenic; D028321:Plant Preparations; D010940:Plant Proteins; D054790:Ribosome Inactivating Proteins, Type 2; D014118:Toxins, Biological; C009674:ribosome inactivating protein, Viscum; D014316:Tritium; D007930:Leucine; D013936:Thymidine