The Effects of TiO₂ Nanoparticles on Cisplatin Cytotoxicity in Cancer Cell Lines

There have been many studies on improving the efficacy of cisplatin and on identifying safe compounds that can overcome multi-drug resistance (MDR) acquired by cancer cells. Our previous research showed that polyethylene glycol-modified titanium dioxide nanoparticles (TiO₂ PEG NPs) affect cell membrane receptors, resulting in their aggregation, altered localization and downregulation. TiO₂ PEG NPs may affect P-glycoprotein (P-gp), a membrane efflux channel involved in MDR. In this study, we investigated the effect of TiO₂ PEG NPs on cisplatin cytotoxicity. We used HepG2 cells, which highly express P-gp and A431 cells, which show low expression of P-gp. The results showed that 10 µg/mL 100 nm TiO₂ PEG NPs increased intracellular cisplatin levels and cytotoxicity in HepG2 cells but not in A431 cells. TiO₂ PEG NPs treatment decreased the expression level of P-gp in HepG2 cells. Our findings indicate that TiO₂ PEG NPs enhance cisplatin cytotoxicity by down regulating P-gp and that TiO₂ PEG NPs are promising candidates for inhibiting P-gp and reversing drug resistance acquired by cancer cells.