title: P-glycoprotein expression in human breast cancer cells.
abstract: Multidrug resistance in Chinese hamster ovary cells is associated with the Mr 170,000 surface glycoprotein. Using our monoclonal antibody to this protein, we have isolated a complementary DNA clone from an expression vector library. This complementary DNA recognizes a 4.5-kilobase mRNA in drug-resistant but not-sensitive Chinese hamster ovary cells; it also recognizes a 5.0-kilobase mRNA in our Adriamycin-resistant subline of the MDA-231 human breast cancer cell line which is not expressed in the drug-sensitive parent line. Southern blot analysis shows that the P-glycoprotein sequences are greatly amplified in resistant Chinese hamster ovary cells but not in the resistant human breast cancer cells, indicating that amplification and expression of the Mr 170,000 P-glycoprotein gene are not necessarily coordinate events. Amplification of this gene may not be required for multidrug resistance in human cells.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D001483:Base Sequence; D001943:Breast Neoplasms / Q000032:analysis*; D002460:Cell Line; D006224:Cricetinae; D004247:DNA / Q000302:isolation & purification; D004351:Drug Resistance; D005260:Female; D005784:Gene Amplification; D006023:Glycoproteins / Q000032:analysis / Q000235:genetics*; D006801:Humans; D014158:Transcription, Genetic
chemical_list: D000911:Antibodies, Monoclonal; D006023:Glycoproteins; D004247:DNA