Abstract
Upon exposure to chemotherapeutic drugs, mammalian cells can acquire resistance to structurally and functionally unrelated compounds, a property known as multidrug resistance (MDR). One MDR mechanism, i.e. by the overexpression of a plasma membrane protein, P-glycoprotein (P-gp), has been identified at the molecular level. The mdr1 gene-encoded P-gp acts as a drug efflux pump, lowering intracellular drug concentration by active extrusion of drugs from the cell. The role of P-gp in determining clinical resistance to multiple anticancer drugs is likely to be largely different for various tumor types. Recently we selected a monoclonal antibody (mAb LRP56) for strong, granular cytoplasmic reactivity with MDR tumor cell lines without P-gp (over)expression. None or weak reactivity was observed with parental and P-gp positive cell lines. We hypothesize that as yet-undefined drug transport-mediating proteins are inserted in intracellular membranes lining the exocytotic compartment and thus may contribute to clinical multidrug resistance.
Original language | English (US) |
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Pages (from-to) | 25-32 |
Number of pages | 8 |
Journal | Clinica Chimica Acta |
Volume | 206 |
Issue number | 1-2 |
DOIs | |
State | Published - Mar 13 1992 |
Externally published | Yes |
Keywords
- Exocytosis
- Multidrug-resistance
- P-glycoprotein
- Transporter proteins
ASJC Scopus subject areas
- Biochemistry
- Clinical Biochemistry