Doxorubicin synergism and resistance reversal in human neuroblastoma BE(2)C cell lines: An in vitro study with dextran-catechin nanohybrids

Hybrid nanocarrier consisting in nanographene oxide coated by a dextran-catechin conjugate was proposed in the efforts to find more efficient Neuroblastoma treatment with Doxorubicin chemotherapy. The dextran-catechin conjugate was prepared by immobilized laccase catalysis and its peculiar reducing ability exploited for the synthesis of the hybrid carrier. Raman spectra and DSC thermograms were recorded to check the physicochemical properties of the nanohybrid, while DES measurements, SEM, TEM, and AFM microscopy allowed the determination of its morphological and dimensional features. A pH dependent Doxorubicin release was observed, with 30 and 75% doxorubicin released at pH 7.4 and 5.0, respectively. Viability assays on parental BE(2)C and resistant BE(2)C/ADR cell lines proved that the high anticancer activity of dextran-catechin conjugate (IC50 19.9 +/- 0.6 and 18.4 +/- 0.7 mu g mL(-1)) was retained upon formation of the nanohybrids (IC50 24.8 +/- 0.7 and 22.9 +/- 1 mu g mL(-1)). Combination therapy showed a synergistic activity between doxorubicin and either bioconjugate or nanocarrier on BE(2)C. More interestingly, on BE(2)C/ADR we recorded both the reversion of doxorubicin resistance mechanism as a consequence of decreased P-gp expression (Western Blot analysis) and a synergistic effect on cell viability, confirming the proposed nanohybrid as a very promising starting point for further research in neuroblastoma treatment.