Expression of gelatinases A and B and their endogenous regulators in immortal and transformed fibroblasts

Abstract

Matrix metalloproteinases (MMP) play a critical role in tumor invasion and metastasis. The aim of this study was to elucidate peculiarity of expression of gelatinases A and B (MMP-2 and MMP-9), membrane type MMP (MT1-MMP) and tissue inhibitor of MMP (TIMP-2) in immortal (IF) and transformed fibroblasts (TF).The study was carried out using embryo rat fibroblasts, sequentially immortalized with the polyomavirus LT gene and transformed with the E7 gene of human papilloma virus (HPV-16). Papilloma virus type 16 and 18 are etiological factors of cervical cancer. The primary fibroblast (PF) culture of Fisher rats was used as control. Analysis of TF and IF involved: determination of MMP-2 and MMP-9 activity by hydrolysis of specific substrate--radioactive collagen type IV; obtaining of MMP spectra by zimographic assay and estimation of the mRNA expression (by RT-PCR) of MMP-2, MMP-9, MT1- MMP and TIMP-2. It was found: 1) collagenolytic activity of MMP was increased only in TF and was dependent on the degree of cell tumorogenity; 2) the study of MMP spectra was shown that MMP-9 was found in TF only but MMP-2 was found in all investigated clones; 3) The mRNA expression of MMP-9, MT1-MMP and TIMP-2 was increased in all TF while the MMP-2 expression was increased in TF only after TF cell selection on rats; 4) The collagenolytic activity as well as the mRNA expression of MMP-2 and MMP-9 themselves and of MMP-2 endogenous regulators (MT1-MMP and TIMP-2) did not change in immortalized fibroblasts compared to PF. The data obtained indicate changes in the enzyme/inhibitor/activator ratio and also suggest of a significant increase in the TF destructive potential. MMP-9 is supposed to be a marker of fibroblasts transformed by E7 HPV-16 gene in cell culture.