[Investigation on the relationship between MDR and expression of N-glycosphingolipids in vincristine resistant KBv200 cell line].
OBJECTIVE
To study the relationship between MDR and expression of N-glycosphingolipids (H-GSLs) in tumor cells.


METHODS
Ribozyme with specific catalytic activity, capable of cleaving mdr1 mRNA, was transfected into KBv200 cells. RNA dot blot was used to detect the expression of ribozyme in the transfected cells. Northern blot and immunocytochemistry were employed to examine the expression of mdr1 mRNA and P-glycoprotein. Cellular N-GSLs was isolated and purified with a modified Hakamori's method and analysed by high performance TLC. The effect of DL-PPMP, a glycolipids synthase inhibitor, on the reversion of MDR was assayed by MTT method.


RESULTS
The ribozyme stably expressed in KBv200/5mR3 cells decreased the level of mdr1 mRNA expression by 81.9% and inhibited the formation of P-glycoprotein. The levels of monohexosylceramide (CMH) and dihexosylceramide (CDH) in KBv200 cells were increased as compared to those in KB cells. When MDR was reversed by the ribozyme, the KBv200/5mR3 showed a sharply decreased level of CMH. PPMP could reverse MDR by inhibiting synthesis of CMH.


CONCLUSIONS
CMH is a kind of MDR-related glycolipid. Inhibition of its expression in tumor cells may be a new approach to reverse MDR.
Zhang
J
J
Oncology Center, Zhujiang Hospital, First Military Medical University, Guangzhou 510282, China.
Zhang
J
J
Yuan
Y
Y
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D015152:Blotting, Northern; D002554:Cerebrosides / Q000378:metabolism; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D006028:Glycosphingolipids / Q000096:biosynthesis* / Q000378:metabolism; D006801:Humans; D007624:KB Cells; D016337:RNA, Catalytic / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D014281:Trihexosylceramides / Q000378:metabolism; D014750:Vincristine / Q000494:pharmacology*
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000972:Antineoplastic Agents, Phytogenic; D002554:Cerebrosides; D006028:Glycosphingolipids; D016337:RNA, Catalytic; D012333:RNA, Messenger; D014281:Trihexosylceramides; C013870:ceramide monohexoside; C012905:dihexosylceramide; D014750:Vincristine