Fig. 2. Non-raft proMMP9 is processed at the cell surface. (A) Gelatinolytic activity in MMP9-GPI and MMP9-LDL-expressing MCF-7 and DU-145 cell extracts. (B) MMP9-GPI and MMP9-LDL, partially purified from MCF-7 cell extracts, were incubated alone () or with
2-MG (+), then analyzed by gelatin zymography. (C) Samples in B were incubated alone or with
2-MG in the presence (+) or absence () of 4-aminophenylmercuric acetate (APMA) before gelatin zymography. (D) Insect cell-derived MMP9-GPI and MMP9-LDL were in vitro processed with APMA before gelatin zymography. (E) MCF-7 cells expressing MMP9-LDL were incubated with DMSO, BB-94, GM6001, aprotinin, anti-uPA or PAI-1, and cell extracts were analyzed by gelatin zymography. In all zymograms, solid and open arrowheads indicate the migration of proMMP9 and MMP9 forms, respectively. Activity is also shown in HT-1080 medium (H). (F) Zymograms in E were analyzed by densitometry and the quotient between the intensities obtained for MMP9 and proMMP9 calculated. The values represent mean±s.d. of results obtained in two independent experiments.