The first individual peak in each histogram represents the size distribution of BSA, and the second represents that of liposomes. The results indicated that after the dilution of liposomes in serum model, the size distribution of each sample was similar as TPCA-1 separately measured (Figure 3A), while after a 24-h incubation, the well-separated peaks for BSA and liposomes still appeared in the mixture, which is an indication of good serological stability. However, the non-irrad liposomes in the mixture showed a much broader size distribution (Figure 3B). The results revealed that after the UV irradiation, our liposomes showed better DNA Damage inhibitor stability in the serum model than non-irrad
ones. Figure 3 Liposomal in vitro serum stability assessment. Up panel: size distribution of the liposome dilution in RPMI 1640 containing 50% (m/v) BSA. Down panel: size distribution of the above dilution after the incubation at 37°C for 24 h. Red, liposomes before UV irradiation; black, liposome after UV irradiation. Intracellular uptake of liposomes For the evaluation of intracellular uptake of our CD20-targeting Selleckchem Verubecestat liposomes, the ADR-loaded liposomes,
PC-ADR-BSA and PC-ADR-Fab, were incubated with CD20+ Raji and Daudi cells for 4 h. After washing, the flow cytometer (FCM) and inverse fluorescent microscopy were used to evaluate the ADR fluorescence (red) in lymphoma cells. As indicated by the mean fluorescence intensity (MFI) of FL-2 (Figure 4A), the PC-BSA (green hitograms) and PC-Fab (blue hitograms) significantly enhanced the intracellular uptake of ADR compared with free drugs (red hitograms) (**p = 0.000), while the increasing extent of PC-Fab is much higher than that of PC-BSA (**p = 0.000). This result was confirmed by the inverse fluorescent microscopy as displayed in Figure 4B. Figure 4 Cellular uptake and intracellular accumulation of ADR-loaded liposomes. (A) Detection of ADR fluorescence intensity
by FCM. Up panel: the histogram represents the fluorescence Bcl-w intensity distribution of Raji and Daudi cells. Black histogram, no-treat; red histogram, free ADR treatment; green, PC-ADR-BSA treatment; blue, PC-ADR-Fab treatment. Down panel: Numerical data representing the mean fluorescence intensity (MFI) of ADR fluorescence in Raji and Daudi cells. Data are mean ± SD of at least three experiments. (B) The effects of liposomes on the intracellular uptake indicated by the inverse fluorescent microscopy. Red fluorescence represents the intracellular ADR. Scale bar 50 μm. In vitrocytotoxicity assays The in vitro antitumor activities of our liposomes were subsequently evaluated. After the incubation of Raji and Daudi cells with different concentrations of free ADR, rituximab Fab fragments, PC-ADR-BSA, and PC-ADR-Fab for 48 h, a CCK-8 assay was employed to determine the cell viability.