Fig. 3.

The effect of NucA modification on the uptake of the conjugated PTX-Rh. a The interaction of nucleolin with NucA and NucA-PTX, respectively, detected by isothermal titration calorimetry (ITC). NucA or NucA-PTX was injected into nucleolin at a 10:1 ratio in 19 portions (each portion 2 μL) at 25 °C. b The time-dependent cellular uptake of the conjugated PTX-Rh in SKOV3 cells examined by flow cytometry. SKOV3 cells were incubated with either NucA-PTX-Rh or CRO-PTX-Rh at a concentration of 500 nM for 1 to 6 h. Error bars indicate mean ± standard deviation. n = 5, *P < 0.05. c The concentration-dependent cellular uptake of the conjugated PTX-Rh in SKOV3 cells examined by flow cytometry. SKOV3 cells were incubated with either NucA-PTX-Rh or CRO-PTX-Rh at a range of concentrations for 2 h. Error bars indicate mean ± standard deviation. n = 5, *P < 0.05. d The nucleolin expression on cell surface, and the uptake of NucA-PTX-Rh or CRO-PTX-Rh in SKOV3, OVCAR3 and L02 evaluated by flow cytometry. The cells were treated with NucA-PTX-Rh or CRO-PTX-Rh at a concentration of 100 nM for 2 h. The nucleolin expression was detected using Alexa488-labeled anti-nucleolin antibody shown in the FITC channel, and the rhodamine level of the conjugates was shown in the PE channel. e The cellular uptake of NucA-PTX-Rh in SKOV3 pre-incubated with either NucA (NucA Pre) or CRO (CRO Pre) analyzed by flow cytometry. The cells were pretreated with 250 nM NucA or CRO for 2 h before incubated with 100 nM NucA-PTX-Rh for 2 h. The rhodamine level of NucA-PTX-Rh was shown in the PE channel