Gene Therapy For Colorectal Cancer By Adenovirally Delivered Tissue Inhibitor Of Metalloproteinases-3

Colorectal carcinoma is one of the most frequent cancer disease. For patients with this type of cancer, liver metastases are the main cause of death. The overall survival has not been improved. Therefore, new therapeutic approaches are urgently needed.Metastatic tumor cells are known to produce a variety of proteolytic enzymes that are required to degrade Extracellular Matrix (ECM), promoting intravasation and extravasation. Among which are Matrix Metalloproteinases (MMPs), a family of molecules that collectively have the capacity to degrade the major components of the ECM and that have been extensively implicated in cancer progression. Several studies have demonstrated elevated levels of MMPs in colorectal cancer. TIMP-3, a new member of the TIMPs family, shares the capacity to inhibit MMPs activity. Overexpression of TIMP-3 reduced primary tumor growth as well as hematogenous metastasis of some kinds of tumors. TIMP-3 was found decreased significantly in human colorectal cancer.Both mRNA and protein levels of TIMP-3 were decresed significantly in colorectal cancer tissue when compared with normal mucosa, suggested that decrease of TIMP-3 expression was correlate with malignant behavior of colorectal cancer. We demonstrated the high susceptibility of CT26 cell to adenovirus by transfection of Ad-GFP.Over expressed TIMP-3 in adenovirally infected CT26 cells was assessed by RT-PCR and western blot. The activity of MMP-2 and MMP-9 could be inhibit by TIMP-3 and was assessed by reversed gelatin zymography. Cell cycle analysis demonstrated that CT26 cell was arrested in G1/S phase by Ad-TIMP-3. Marked pro-apoptosis effect of TIMP-3 was certified by Flow Cytometry, DNA Ladder and DAPI stain respectively. MTT assay showed that the CT26 cell survival was significantly decreased by Ad-TIMP-3. In vitro data...