Due to the wide range of MMPs activities in tumor, there is not an exact conclusion on the mechanism of MMP promoting metastasis.
It remains to clarify the role of TIMP-2, that was found upregulated in 4G-BMHP1 and saline-injected groups in comparison with SCI control group: even if TIMP-2 inhibits a broad range of MMPs, some authors have suggested that it may have a role also as activator of MMP-2 [47].
For invasion assays in which human recombinant MMP-3 was included (R&D Systems Europe Ltd, Abingdon, Oxfordshire), a range of MMP-3 concentrations (12.5 to 100 ng/mL) was added at the start of the assay.
To determine the range of MMP-12 concentrations in human induced sputum, 38 induced sputum samples were collected from asthma, COPD, and normal donors (Additional file 1, Table S4).
The cutoff point analysis showed a broad range of MMP-2 levels with a significant and unidirectional relation with survival outcome: high tumour MMP-2 levels are unfavourable for the patients' prognosis.
Based on the LLOQ of 50 pg/mL and the ULOQ of 1,600 pg/mL, the reportable range of MMP-12 in human induced sputum is 400 to 12,800 pg/mL.
To determine the range of MMP-12 concentrations in human induced sputum, and to determine the effect of IIR, 38 induced sputum samples were collected from asthma, COPD and normal donors (Additional file 1, Table S4).
Using a range of MMP-deficient mice (MMP13−/−, MMP8−/−, MMP2−/−, MMP9−/−, MMP14−/− (or MT1-MMP−/−) and MMP16−/− (or MT3-MMP−/−)), Sabeh and colleagues demonstrated that only the membrane-anchored MMP14 is required for focal collagen invasion required for FB migration through the stroma, compared with bulk collagenolysis by the soluble MMPs [ 89].
The different sensitivity of MMP-14 interference in tumor formation is to be expected considering glioma cells express a wide range of MMPs and MMP-14 contribution could vary between glioblastoma subtypes 41.
