Figure 6

In vitro cytotoxicity assessment of anti-PLAC1-ADC. Prostate cancer cells and LS180, as negative cell control, were treated with 2.5 µg/mL anti-PLAC1 antibody or anti-PLAC1-ADC, equivalent concentration of free SN38, or remained untreated. Cell morphology was visualized after 48 h under microscope (a). LNCaP cells were treated with different concentrations of free SN38 or equivalent concentrations of anti-PLAC1-ADC or isotype-matched-ADC and the rate of cell cytotoxicity was assesses by Calcein AM fluorimetric assay (b). Calcein AM-labeled LNCaP cells were inspected under fluorescent microscope 36 h after treatment with 2.5 µg/mL anti-PLAC1-ADC, isotype-matched-ADC, anti-PLAC1 antibody or equivalent concentration of free SN38 (c). IC₅₀ values for free SN38 and anti-PLAC1-ADC were determined using the Prism software as described in materials and methods (d). Data were generated from four independent experiments. *Anti-PLAC1-ADC vs. free SN38, ^ϕanti-PLAC1-ADC vs. isotype-matched-ADC, *or ^ϕp < 0.05, ** or ^ϕϕp < 0.01, *** or ^ϕϕϕp < 0.001, **** or ^ϕϕϕϕp < 0.0001.