Active efflux system for cisplatin in cisplatin-resistant human KB cells

Area of Science:

• Molecular Biology
• Cancer Research
• Pharmacology

Background:

• Cisplatin is a widely used anticancer agent.
• Acquired resistance to cisplatin is a significant clinical challenge in cancer therapy.
• Understanding the mechanisms of cisplatin resistance is crucial for developing effective treatments.

Purpose of the Study:

• To investigate the mechanisms of cisplatin resistance in selected human cancer cell lines.
• To characterize the role of cisplatin accumulation and efflux in acquired resistance.
• To identify potential cellular targets or pathways involved in cisplatin resistance.

Main Methods:

• Selection of cisplatin-resistant cell lines (KCP-4 and PC-5) from parental KB and PC-3 cells.
• Quantification of intracellular cisplatin accumulation.
• Assessment of cross-resistance to other anticancer drugs.
• Analysis of cisplatin efflux using 2,4-dinitrophenol and glucose.
• Cell-cell hybridization studies to assess inheritance of resistance traits.

Main Results:

• KCP-4 and PC-5 cells exhibited significant resistance to cisplatin (63-fold and 10-fold, respectively).
• Resistant cells showed reduced intracellular accumulation of cisplatin (approx. 20% of parental cells).
• 2,4-dinitrophenol increased cisplatin accumulation in resistant cells, suggesting an active uptake or reduced efflux.
• Enhanced active efflux of cisplatin was observed in KCP-4 cells.
• Cisplatin resistance and accumulation defect behaved as codominant traits in cell hybridization.

Conclusions:

• An active efflux system for cisplatin likely exists in cisplatin-resistant KCP-4 cells.
• Defects in cisplatin accumulation, potentially due to active efflux, contribute to acquired cisplatin resistance.
• These findings provide insights into mechanisms of anticancer drug resistance and potential therapeutic targets.