Background & objective: Heparanase (Hpa) is an endoglycosidase that degrades heparin sulfate--the main polysaccharide constituent of extracellular matrix (ECM) and basement. It can enhance the invasive and metastatic potential of malignant tumors and cell lines by destroying ECM and basement. This study was to explore the effects of heparanase gene on the invasive ability of colorectal cancer cell line HT29.
Methods: Heparanase gene was transfected into HT29 cells. Cell growth kinetics was assessed by MTT assay, and in vitro invasive ability was assessed with Boyden chamber. Xenograft and orthotopic implantation of histologically intact tumor in nude mice were constructed to observe the effect of exogenous expression of heparanase gene on invasive ability of HT29 cells.
Results: After transfection, the growth rate of heparanase-transfected HT29 (HT29-Hpa) cells was obviously higher than those of untransfected HT29 cells and empty vector-transfected HT29 (HT29-KZ) cells; the invasive cell number was significantly larger in HT29-Hpa cells than in untransfected HT29 cells and HT29-KZ cells (45.5+/-0.5 vs. 29.3+/-0.1 and 30.1+/-0.2, P<0.01). The entity neoplasm formed by HT29-Hpa cells (12 mm x 9 mm x 10 mm) was bigger than that formed by untransfected HT29 cells (6 mm x 8 mm x 6 mm). The prevalence of liver metastasis caused by orthotopic implantation of xenograft was significantly higher in HT29-Hpa group than in control group (71.43% vs. 14.29%, P<0.01).
Conclusion: Exogenous heparanase gene can facilitate the growth, invasion, and metastasis of HT29 cells.