[Expression of MT1-MMP and RECK protein in human gastric carcinoma].

OBJECTIVE: To examine the expression of membrane-type-1 matrix metalloproteinase (MT1-MMP) and reversion-inducing cysteine-rich protein with Kazal motifs (RECK) in gastric carcinoma, and investigate its clinical significance, at the same time analyze the correlation between MT1-MMP and RECK expression. METHODS: MT1-MMP and RECK expression in surgically resected tissue samples of gastric carcinoma was examined by immunohistochemical method (two-step method) , and its correlation with clinicopathological factors was analyzed. RESULTS: Among the 44 gastric carcinoma samples, 37 (84.1%) were stained positive for MT1-MMP, and 31 (70.5%) for RECK. The expression of MT1-MMP was much higher in poorly differentiated gastric carcinoma samples than moderately and well-differentiated samples (P = 0.015). The expression level of MT1-MMP was associated with invasive depth of tumor cells (P = 0.007), but no difference between sex and lymph node metastasis. On the contrary, the well-differentiated samples showed higher expression of RECK than poorly and moderately differentiated gastric carcinoma samples (P = 0.006). The expression level of RECK did not correlate with sex, lymph node metastasis and invasive depth of tumor cells. RECK expression showed no relation to MT1-MMP expression in the gastric carcinoma. CONCLUSION: Overexpression of MT1-MMP in gastric carcinoma may play an important role during tumor differentiation and metastasis, the RECK protein may have positive effects on the tumor differentiation.

A suppressor of multiple extracellular matrix-degrading proteases and cancer metastasis.

Cancer metastasis remains the most poorly understood process in cancer biology. It involves the degradation of extracellular matrix (ECM) proteins by a series of 'tumour-associated' proteases. Here we report the identification of a novel protease suppressor, NYD-SP8, which is located on human chromosome 19q13.2. NYD-SP8 encodes a 27 kD GPI-anchored cell surface protein, which shows structural homology to urokinase plasminogen activator receptor (uPAR). Co-immunoprecipitation experiments showed that NYD-SP8 binds to uPA/uPAR complexes and interfere with active uPA production. Overexpression of NYD-SP8 results in reducing activities of the three major classes of proteases known to be involved in ECM degradation, including uPA, matrix metalloproteinases (MMPs) and cathepsin B, leading to suppression of both in vitro and in vivo cancer cell invasion and metastasis. These data demonstrate an important role of NYD-SP8 in regulating ECM degradation, providing a novel mechanism that modulates urokinase signalling in the suppression of cancer progression.

Altered distribution of beta-catenin and prognostic roles in colorectal carcinogenesis.

OBJECTIVE: Although beta-catenin cytoplasmic stabilization and nuclear translocation play a key role in initiation of colorectal cancer (CRC), the mechanisms are far from clear. The aim of this study was to investigate the relation of expressions of cyclooxygenase (COX)-2 and E-cadherin, and the beta-catenin gene exon 3 mutation to the altered distribution of beta-catenin, and their roles in CRC progression and prognosis. MATERIAL AND METHODS: Expressions of beta-catenin, COX-2 and E-cadherin in 96 tissue specimens were detected by immunohistochemistry, and mutation of beta-catenin gene exon 3 was screened by polymerase chain reaction (PCR) and denaturing high-performance liquid chromatography (DHPLC). RESULTS: Cytoplasmic/nuclear expression of beta-catenin and reduced membranous expression of E-cadherin were associated, respectively, with the earlier and later stages of sequential colorectal carcinogenesis (p<0.05). The altered distribution of beta-catenin was significantly associated with both high Dukes' stages and poor differentiation of CRC (p<0.05). It also had a parallel relationship with COX-2 overexpression (p<0.05, Spearman's rank analysis), but not with reduced E-cadherin expression. Kaplan-Meier analysis showed a significantly worse survival rate for CRC patients with altered expression of beta-catenin (p<0.05, log-rank test). Nevertheless, we failed to find any exon 3 mutation of beta-catenin gene in all 60 cases of CRC. CONCLUSIONS: Altered distribution of beta-catenin occurs in the early stage of colorectal carcinogenesis and has a parallel relationship with COX-2 overexpression. It may serve as a potential marker for the progression and prognosis of CRC. The exon 3 mutation did not appear contributive to the abnormal expression of beta-catenin in CRCs in a Chinese population.