Matrix metalloproteases regulation in colorectal adenocarcinoma cells exposed to X-rays

Matrix metalloproteases (MMPs) are degradation enzymes that allow cells to migrate through the extracellular matrix. MMPs generate new binding sites for tumour cell receptors that stimulate migration and invasion of normal tissues, leading to metastasis. In our Radiation Biophysics and Radiobiology Laboratory we have started an extensive experimental characterization of the response to X-rays (up to 10 Gy) of Caco-2 cells: this cell line is derived from human colorectal adenocarcinoma, usually adopted as an intestinal barrier model and recently characterized as radio-resistant. Colorectal cancer is among the three top cancer types for incidence and the second for mortality, usually treated with surgery, chemotherapy and radiotherapy. We performed gelatine zymography analysis, to evaluate MMP-2 and MMP-9 activity, which has been little investigated as a function of radiation dose and time after exposure. We here report results on the dose-dependent inhibition of these MMPs, also showing that measurements of MMPs activation can be severely affected by the choice of the experimental protocol, and particularly by the temporal sequence of radiation treatment and cell seeding.