Figure 3

Cathepsins and in vitro invasiveness: effect of chemical and biological inhibitors. (A) Invasion test on primary (white columns) and metastatic (black columns) melanoma cell lines. (B) Invasion test on two representative cell lines from primary (white columns) and metastatic (black columns) melanoma in the presence of CA-074 (left panel), Pepstatin A (central panel) or cathepsin L inhibitor (right panel). Dotted lines represent the mean of the results obtained in primary melanoma cell lines, and dashed lines indicate the mean of the results obtained in metastatic melanoma cell lines by using DMSO (vehicle of the cathepsin inhibitors). (C) Invasion test on two representative cell lines from primary (white columns) and metastatic (black columns) melanoma in the absence or in the presence of specific antibodies against cathepsin B (left panel), cathepsin D (central panel) or cathepsin L (right panel). Dotted lines represent the mean of the results obtained in primary melanoma cell lines, and dashed lines indicate the mean of the results obtained in metastatic melanoma cell lines by using IgG1 as positive control. (D) Histogram showing the results obtained from four different primary melanoma (white columns) or metastatic melanoma (black columns) cell lines in the absence or in the presence of CA-074 or antibodies against cathepsin B. Data are reported as mean ± SD of the percentage of invading cells. Student's t-test indicates: p = 0.0097 for untreated MM cells vs. CA-074-treated MM cells and p = 0.0030 for untreated MM cells vs. MM cells treated with anti-cathepsin B antibodies.