Expression of functional MMP-9 by GLV-1h255-infected tumor cells. (A) Expression cassettes of GLV-1h68 and GLV-1h255. In GLV-1h255 the insert in the Tk locus was replaced by the human mmp-9 gene under control of the PSE promoter. PSEL, synthetic early/late promoter; PSE, synthetic early promoter; P7.5, VACV p7.5 K early/late promoter; P11, VACV p11 late promoter; Tk, thymidine kinase locus, Ha, hemagglutinin locus. (B) Expression of virus-encoded MMP-9 (92 kDa) in GLV-1h255 infected PC-3 cells and supernatants in vitro, β-actin (42 kDa) was used as a loading control. (C) Activity of the MMP-9 protein was tested by gelatin zymography. Lysates and supernatants of infected A549 cells were isolated and separated by non-reducing SDS-PAGE. In zymography, cleavage of the substrate by MMP-9 resulted in a clear band.
Schäfer et al. BMC Cancer 2012 12:366 doi:10.1186/1471-2407-12-366