Vinblastine, a chemotherapeutic drug, inhibits palmitoylation of tubulin in human leukemic lymphocytes.
BACKGROUND
We have previously shown that tubulin, the major protein of microtubules, is posttranslationally modified by palmitoylation. In addition, we demonstrated that palmitoylation of tubulin is inhibited in vitro by stoichiometric levels of the chemotherapeutic drug, vinblastine. Here, we sought to determine whether a clinically relevant dose of vinblastine inhibits palmitoylation of tubulin in vivo.


METHODS
Human CEM leukemic lymphocytes were incubated with [3H]palmitate in the presence and absence of a low, clinically relevant dose of vinblastine. [3H]palmitoylated tubulin was identified by two-dimensional PAGE and autoradiography.


RESULTS
We found, first, that tubulin was palmitoylated in CEM cells. Second, the clinically relevant dose of vinblastine inhibited palmitoylation of tubulin in vivo in CEM cells. In addition, microtubules were disassembled and cells became apoptotic.


CONCLUSIONS
This study identifies a previously unknown mechanism of action of vinblastine, the depalmitoylation of tubulin, and suggests that depalmitoylation of tubulin may be a target for new chemotherapeutic drugs.
Caron
Joan M
JM
Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06030, USA. caron@nsol.uchc.edu
Herwood
Margot
M
D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D017209:Apoptosis; D045744:Cell Line, Tumor; D006801:Humans; D007945:Leukemia, Lymphoid / Q000378:metabolism*; D008214:Lymphocytes / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D008870:Microtubules / Q000737:chemistry / Q000187:drug effects / Q000648:ultrastructure; D010168:Palmitates / Q000378:metabolism*; D014404:Tubulin / Q000032:analysis / Q000378:metabolism*; D014747:Vinblastine / Q000494:pharmacology*
D000972:Antineoplastic Agents, Phytogenic; D010168:Palmitates; D014404:Tubulin; D014747:Vinblastine