Quantification of matrix metalloproteinases and tissue inhibitors of metalloproteinase in prostatic tissue: analytical aspects.

Background: The balance between matrix metalloproteinases (MMP) and the tissue inhibitors of metalloproteinases (TIMP) has been seen as important during tumor invasion and progression. The determination of these components needs a special strategy of tissue preparation. This analytical problem has not been considered for prostatic tissue.

Methods: We adapted an extraction method consisting of two extraction steps with 0.25% Triton X-100/CaCl2 solution and two heat extraction steps at 60 degrees C for 4 min. This combination allowed a complete extraction of MMP (measured as enzyme activity) and TIMP-1 (measured with an ELISA test) from cancerous and normal prostatic tissue samples.

Results: The median values for cancerous vs. normal MMPs (50.8 mU/g wet tissue and 1,580 mU/g protein vs. 88.8 and 2,497) and TIMP-1 (4.49 micrograms/g wet tissue and 96.7 micrograms/g protein vs. 12.4 and 237.8) were significantly lower, whereas the respective ratios for MMP/ TIMP-1 (11.1 vs. 4.0 on wet weight and 15.5 vs. 5.3 on protein basis) were significantly higher.

Conclusions: An optimized extraction procedure was elaborated for determining MMPs and TIMP-1 in prostatic tissue samples. The increased ratio of MMP/TIMP-1 can be interpreted as an indicator of the imbalance between MMP and TIMP, characteristic of prostate carcinoma tissue.