Abstract
BackgroundCathepsins represent a group of proteases involved in determining the metastatic potential of cancer cells. Among these are cysteinyl- (e.g. cathepsin B and cathepsin L) and aspartyl-proteases (e.g. cathepsin D), normally present inside the lysosomes as inactive proenzymes. Once released in the extracellular space, cathepsins contribute to metastatic potential by facilitating cell migration and invasiveness.ResultsIn the present work we first evaluated, by in vitro procedures, the role of cathepsins B, L and D, in the remodeling, spreading and invasiveness of eight different cell lines: four primary and four metastatic melanoma cell lines. Among these, we considered two cell lines derived from a primary cutaneous melanoma and from a supraclavicular lymph node metastasis of the same patient. To this purpose, the effects of specific chemical inhibitors of these proteases, i.e. CA-074 and CA-074Me for cathepsin B, Cathepsin inhibitor II for cathepsin L, and Pepstatin A for cathepsin D, were evaluated. In addition, we also analyzed the effects of the biological inhibitors of these cathepsins, i.e. specific antibodies, on cell invasiveness. We found that i) cathepsin B, but not cathepsins L and D, was highly expressed at the surface of metastatic but not of primary melanoma cell lines and that ii) CA-074, or specific antibodies to cathepsin B, hindered metastatic cell spreading and dissemination, whereas neither chemical nor biological inhibitors of cathepsins D and L had significant effects. Accordingly, in vivo studies, i.e. in murine xenografts, demonstrated that CA-074 significantly reduced human melanoma growth and the number of artificial lung metastases.ConclusionsThese results suggest a reappraisal of the use of cathepsin B inhibitors (either chemical or biological) as innovative strategy in the management of metastatic melanoma disease.
Highlights
Cathepsins represent a group of proteases involved in determining the metastatic potential of cancer cells
For cell migration and invasion assays, cells were seeded in the presence of the cathepsin D inhibitor (Pepstatin A, 100 μM, Calbiochem), the cathepsin L inhibitor as well as two cathepsin B inhibitors: CA074 and CA-074Me
Expression of cathepsins in cells from primary and metastatic human melanomas We analyzed the total amount of cathepsin B, D and L in four cell lines derived from human metastatic melanomas (MM1-MM4) and in four cell lines derived from primary lesions (PM1-PM4) by means of Western blotting
Summary
Cathepsins represent a group of proteases involved in determining the metastatic potential of cancer cells. Among these are cysteinyl- (e.g. cathepsin B and cathepsin L) and aspartyl-proteases (e.g. cathepsin D), normally present inside the lysosomes as inactive proenzymes. Cathepsins are a large family of cysteinyl-, aspartyl- and serine-proteases composed of at least twelve different molecules, which are distinguished by their structure, catalytic mechanism, and substrate specificity [1,2]. They are normally found inside the cell and appear commonly sequestered in well-defined organelles, mainly lysosomes, as inactive proenzymes [3]. The key role of cathepsins in metastatic melanoma progression has been investigated in several experimental and clinical studies, where overexpression of cathepsins was associated with a worse prognosis and high cancer dissemination [10,11,12,13]
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.