A Heparan Sulfate-Binding Cell Penetrating Peptide for Tumor Targeting and Migration Inhibition

Figure 1

Effect of surface HS level on CPPecp binding to CT-26 cells. (a) CT-26 cells were preincubated at 4°C for 30 min and then incubated with 5 μM FITC-CPPecp for 1 h. The cells were washed twice with 500 μL PBS, trypsinized at 37°C for 15 min, suspended in 500 μL PBS, and subjected to flow cytometry. (b) CT-26 cells were stained with anti-HS monoclonal antibody (10E4) at 4°C for 1 h, washed twice with 500 μL PBS, and hybridized with FITC-conjugated anti-mouse secondary antibody at 4°C for 1 h. After being washed twice with 500 μL PBS, cells were suspended in 500 μL PBS and subjected to flow cytometry. (c) CT-26 cells were treated with 5 μM FITC-CPPecp at 37°C for 10 min. Uptake of FITC-CPPecp by CT-26 cells was examined by fluorescent microscopy. FITC was set as a negative control. DAPI staining of cells indicated intact nucleus. Scale bars in panel represented 10 μm. Green, FITC-labeled CPPecp; blue, DAPI (nucleus). (d) CT-26 cells were pretreated with or without heparinase II (2.5 milliunit/mL) at 37°C for 2 h followed by treatment with 5 μM TMR-CPPecp at 37°C for 10 min. Uptake of TMR-CPPecp by CT-26 cells was examined by fluorescence microscopy. TMR-CPPecp bound on CT-26 tumor cell DAPI staining of cells indicated intact nucleus. Scale bars in panel represented 10 μm. Red, TMR-labeled CPPecp; blue, DAPI (nucleus).

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