EXPRESSION OF INTERSTITIAL COLLAGENASE AND ITS ENDOGENOUS REGULATORS IN IMMORTALIZED AND TRANSFORMED BY E7 GENE HPV16 FIBROBLASTS
Matrix metalloproteinases (MMPs) play a critical role in tumor development and invasion. The aim of this study is to elucidate peculiarity of expression of interstitial collagenase (MMP-1) and its endogenous regulators in the process of oncogenic transformation of fibroblasts by E7 gene of HPV16. Papilloma virus type 16 and 18 are aetiological factor of cervical cancer. We have studied expression of MT1-MMP, MMP-1, tissue inhibitor of these proteases - TIMP-1 and urokinase-type plasminogen activator (uAP). The study was carried out using fibroblasts immortalized by LT gene (IF) and transformed by E7 gene of HPV-16 fibroblasts (TF). Primary culture of Fisher rat embryo fibroblasts was used as a control (PF). mRNA expression was studied by RT-PCR, enzymatic activity - by hydrolysis of fluorogenic type I collagen. It was found that cell transformation is accompanied by: a) 2-3 fold induction of MT1-MMP mRNA expression (vs PF); b) the decrease in mRNA level of TIMP-1 (1,5-2 fold); c) unchanged uPA expression. Cell immortalization is accompanied by: a) the increase of MT1-MMP expression (1,5-2 fold); b) unchanged TTMP-1 expression; c) the increase of uPA expression (2-4 fold) (vs PF and TF). MMP secreted activity and activity in lysates of TF increased but the level of free endogenous MMP inhibitors decreased (vs IF). Data on gene expression are consistent with enzymatic data on the collagenolytic activity. These results suggest changes in enzyme/inhibitor/activator ratio both TF and IF and significant enhancement of the destructive potential of the TF.