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Identification of a P-glycoprotein-related protein (mini-P-glycoprotein) which is overexpressed in multidrug
Abstract:
Drug resistant variant cell lines were selected in vitro for resistance to adriamycin or vincristine, P388/ADR and P388/VCR-600, respectively, from P388 murine leukemia cells. These cells were demonstrated by immunoblot studies with P-glycoprotein specific monoclonal antibody (C219) to overexpress not only P-glycoprotein but also approximately 65 kDa protein, and the expression levels were found to correlate with the degree of resistance. Furthermore, in Northern blot analysis with an MDR1 cDNA as a probe, an overexpressed transcript with the length of about 2.4 kilobases which might encode this previously uncharacterized protein was also detected in the multidrug resistant cell line. Thus, it is suggested that this protein might be associated with multidrug resistant phenotype and be related to P-glycoprotein.
Insights
Researchers identified a novel 65 kDa protein overexpressed in multidrug-resistant leukemia cells, potentially linked to P-glycoprotein and drug resistance mechanisms.
Area of Science:
- Molecular Biology
- Cancer Research
- Pharmacology
Background:
- Drug resistance is a major challenge in cancer chemotherapy.
- P-glycoprotein is a known mediator of multidrug resistance (MDR).
Purpose of the Study:
- To investigate the molecular mechanisms underlying adriamycin and vincristine resistance in P388 murine leukemia cells.
- To identify novel proteins associated with the multidrug-resistant phenotype.
Main Methods:
- Selection of drug-resistant cell lines (P388/ADR, P388/VCR-600).
- Immunoblot analysis using P-glycoprotein specific monoclonal antibody (C219).
- Northern blot analysis using MDR1 cDNA probe.
Main Results:
- Drug-resistant cell lines overexpressed P-glycoprotein.
- A novel approximately 65 kDa protein was also overexpressed, correlating with resistance levels.
- An overexpressed transcript of about 2.4 kilobases, potentially encoding the 65 kDa protein, was detected.
Conclusions:
- The novel 65 kDa protein is suggested to be associated with the multidrug-resistant phenotype.
- This protein may be related to the function or regulation of P-glycoprotein in drug resistance.