Effects of macrophage metalloelastase on angiostatin generation and growth of tumor vessels in murine colon carcinoma / 中华消化杂志

ABSTRACT

Objective To determine the pathway of macrophage metalloelastase (MME)generate active angiostatin by decomposing plasminogen and its effect on inhibiting growth of tumor and microvessel density (MVD) in vivo in mouse models. Methods The recombined plasmid pEGFPC1-MME was constructed. Thirty mice were subcutaneously inoculated with CT-26 cells that were stably transfected with pEGFP-C1-MME (MME-transfected group), 30 with CT-26 cells transfected with empty vector pEGFP-C1 (vector-transfected group) and 30 with CT-26 cells (non-transfected group). Radioiodination and radioisotope tracer were used to explore the pathway of angiostatin generation in vivo. Results SDS-PAGE electrophoresis analysis revealed that, in the PAGE gel contained the protein with molecular weights of 35 000 and 38 000, radioactivity in MME-transfected group was significantly higher than vector-transfected and non-transfected groups (P = 0. 00).Western blotting analysis demonstrated two bands containing 35 000 and 38 000 fragments in three groups. Quantification of the protein signals by image analysis revealed that the levels of 35 000 and 38 000 fragments were obviously increased in MME-transfected group (9.32±1.52 and 5.61±2.24,respectively) than those in vector-transfected (2.47 ± 0.23 and 0. 67 ± 0. 12, respectively) and nontransfected (1.21±0. 69 and 0. 86 ± 0.44, respectively) groups (P= 0.00). The average value of MVD and fluorescent express of vascular endothelial growth factor (VEGF) were lower in MMEtransfected group when compared with those in vector-transfected and non-transfected groups (P =0.00). The average tumor size in MME-transfected group was small in comparison with vectortransfected and non-transfected groups (P= 0.00). Conclusions MME is demonstrated to be one of matrix metalloproteinase that closely related with angiostatin production and has inhibitory effect on tumor growth in tumor-bearing mice.