Abstract
BackgroundMatrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), and urokinase-type plasminogen activator (uPA) are involved in colorectal cancer invasion and metastasis. There is still debate whether the activity of MMP-2 and MMP-9 differs between tumors located in the colon and rectum. We designed this study to determine any differences in the expression of MMP-2, MMP-9 and uPA system between colon and rectal cancer tissues.MethodsCancer tissue samples were obtained from colon carcinoma (n = 12) and rectal carcinomas (n = 10). MMP-2 and MMP-9 levels were examined using gelatin zymography and Western blotting; their endogenous inhibitors, tissue inhibitor of metalloproteinase-2 (TIMP-2) and tissue inhibitor of metalloproteinase-1 (TIMP-1), were assessed by Western blotting. uPA, uPAR and PAI-1 were examined using enzyme-linked immunosorbent assay (ELISA). The activity of uPA was assessed by casein-plasminogen zymography.ResultsIn both colon and rectal tumors, MMP-2, MMP-9 and TIMP-1 protein levels were higher than in corresponding paired normal mucosa, while TIMP-2 level in tumors was significantly lower than in normal mucosa. The enzyme activities or protein levels of MMP-2, MMP-9 and their endogenous inhibitors did not reach a statistically significant difference between colon and rectal cancer compared with their normal mucosa. In rectal tumors, there was an increased activity of uPA compared with the activity in colon tumors (P = 0.0266), however urokinase-type plasminogen activator receptor (uPAR) and plasminogen activator inhibitor-1 (PAI-1) showed no significant difference between colon and rectal cancer tissues.ConclusionThese findings suggest that uPA may be expressed differentially in colon and rectal cancers, however, the activities or protein levels of MMP-2, MMP-9, TIMP-1, TIMP-2, PAI-1 and uPAR are not affected by tumor location in the colon or the rectum.
Highlights
Matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), and urokinase-type plasminogen activator are involved in colorectal cancer invasion and metastasis
Activities of MMP-2 and MMP-9 Zymographic detection on substrate gels is often a good choice for the initial characterization of a proteinase activity. This technique permits important information, such as estimated molecular weight and proteinase class, to be obtained. It circumvents two common problems encountered in the assay: (a) Many proenzymes show activity when assayed in this manner, eliminating the requirement for activation. (b) Electrophoresis can result in the separation of non-covalent proteinase-inhibitor complexes
Four gelatinolytic bands which inhibited with MMPs inhibitor, 1,10-phenanthroline could be observed, with molecular masses of 92 kDa, 84 kDa, 72 kDa, and 62 kDa. (Figure 1a,b)
Summary
Matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), and urokinase-type plasminogen activator (uPA) are involved in colorectal cancer invasion and metastasis. We designed this study to determine any differences in the expression of MMP-2, MMP-9 and uPA system between colon and rectal cancer tissues. Tumor cell invasion and metastasis are regarded as multi-step phenomena, involving the proteolytic degradation of the basement membrane (BM) and the extracellular matrix (ECM), altered cell adhesion, and the physical movement of tumor cells. Roeb et al [18] demonstrated differences in MMP-9 activity between colon and rectal cancers. These studies have looked at only the MMP system. No previous study has determined the expression of these two proteinase systems in the different sites of colon and rectal cancer
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
