Fig. 2.

Expression of cathepsin B in target cells. (A) Expressions of mouse cathepsin B (upper panel) and cathepsin L (middle panel) mRNAs in NIH3T3 and XC cells were analyzed by RT-PCR. (B) Expression of human cathepsin B mRNA in human 293T and TE671 cells was analyzed by RT-PCR. A Hind III-digested product of the λ phage DNA was used as molecular size marker (left side of the panels). (C) Cathepsin B activity in living cells was analyzed by incubation of cells with the cathepsin B detection reagent for indicated times. Means of fluorescence intensities (MFIs) of the stained cells were measured by a flow cytometer. Relative values to MFIs of cells incubated with the cathepsin B detection reagent for 0 h are indicated. (D and E) Cathepsin B activities of the CA-074Me-treated cells were measured by the cathepsin B detection reagent. The treated cells were incubated with the cathepsin B detection reagent for 1 h. Histograms are indicated in panel (D). Grey areas in upper panels indicate cells treated with DMSO and unstained with the cathepsin B detection reagent. Open areas indicate cells treated with DMSO and stained with the cathepsin B detection reagent. Grey areas in lower panels indicate cells treated with CA-074Me and stained with the cathepsin detection reagent. Relative values to MFI of DMSO-treated cells are also indicated in panel (E). These experiments were repeated three times. Error bars indicate standard deviations. Asterisks indicate significant differences compared with MFI of the control cells.