[PMC free article] [PubMed] [Google Scholar] 10. death. In conclusion, this study has demonstrated the potential of a new dual-targeting strategy using c(RGDyC)-LP to improve boron neutron capture therapy for glioblastoma. BNCT efficacy of c(RGDyC) modified liposomes containing BSH was assessed on these cell lines by thermal neutron irradiation in comparison with liposomes without peptide paederosidic acid methyl ester modification and a BSH solution. RESULTS Formation of c(RGDyC) modified liposomes A c(RGDyC) (1%, molar ratio) modified liposomal system (c(RGDyC)-LP) for the dual-targeting of tumor vasculature and glioblastoma cells was developed. The c(RGDyC) peptides were conjugated to the liposomal surface through a thiol-maleimide coupling reaction and a high attachment efficiency (>98%) was achieved following 24 h incubation at 22C. A decrease in reaction temperature to 4C resulted in no detectable attachment while an increase in temperature to 37C resulted in 51.9% attachment efficiency. The successful conjugation at 22C was confirmed by the observation that the zeta potential of liposomes dropped by 10 mV (p < 0.01) (Table ?(Table11). Table 1 Particle concentration and stability of BSH loaded liposomes BNCT The effect of neutron irradiation on cell viability Figure ?Figure66 illustrates effect of neutron irradiation alone on HUVEC and U87 cells, expressed as the relative cell viability in comparison with non-irradiated cells (control). Irradiation appeared to stimulate HUVEC and MIA PaCa-2 cell metabolic activity initially resulted in a 150% relative cell viability at 24 h, however the cell viability declined continuously from day 1 with a 13% relative cell viability observed on the 7th day. In contrast, neutron irradiation reduced the relative cell viability of U87 to 50% on day 1 and the cell viability maintained the same growth rate as the control cells up to day 3, however doubled at day 5 before the second drop at day 7. Open in a separate window Figure 6 Cell responses to neutron irradiation in the absence of 10BHUVEC and MIA PaCa-2 cells underwent apoptosis after irradiation while glioblastoma cells U87 showed cell growth. The relative cell viability was obtained by comparing viability with non-irradiated cells maintained medium and monitored over 7 days after irradiation. Results are expressed as mean SD (n=3). The efficacy of BNCT on cell viability Figure ?Figure77 shows the BNCT efficacy with the cells pre-treated with formulations for either 3 h or 16 paederosidic acid methyl ester h prior to 7 h irradiation. The cell viability measured on the 4th day after irradiation was compared to non-irradiated control cells cultured in medium to demonstrate the BNCT efficacy. In both HUVEC and U87 cells with BNCT, the c(RGDyC)-LP pretreatment for 3 h led to PTGFRN the most significant reduction in cell viability compared with LP and BSH solutions. Extending the treatment with formulations to 16 h resulted in lower MTT cell viability close to 20% on HUVECs and 50% in U87 cells, regardless of the formulation (p>0.05). Moreover, U87 cell mutation was observed at day 3 post irradiation, some paederosidic acid methyl ester cells were giant shuttle-shaped and some were longer branched. Open in a separate window Figure 7 Efficacy of BNCT on cell viability of HUVEC and U87 cellsCells were pre-treated with different 10B containing formulations with the final concentration of 20 g/ml 3 h or 16 h. The relative cell viability compared to nonirradiated cells maintained in culture medium was.