Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.3.1.108 (TAT)
 2,389 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous studies have indicated that cyst fluid of ovarian tumors contains 2 trypsinogen isoenzymes, called tumor-associated trypsinogen-I (TAT-I) and trypsinogen-2 (TAT-2), the levels of which correlate with the degree of malignancy of the tumors. In addition, these cyst fluids contain large amounts of tumor-associated trypsin inhibitor (TATI), which is also expressed in many other human tumors. In the present study we examined the production of TAT-I, TAT-2 and TATI in 9 established tumor-cell lines. TAT-2 was produced by 5 cell lines. Its concentration in the conditioned medium of COLO 205 colon adenocarcinoma cells, K-562 erythroleukemia cells and fibrosarcoma cell lines HT 1080, 8387 and A 9733 was 460 micrograms/l, 9.8 micrograms/l, 21 micrograms/l, 8.8 micrograms/l and 0.24 micrograms/l, respectively. TAT-I was detectable in the conditioned medium of COLO 205 and HT 1080 cells at concentrations of 64 micrograms/l and 0.5 micrograms/l, respectively. TATI was detected only in the media of COLO 205 cells at a concentration of 23 micrograms/l. TAT-2 zymogen was purified from the conditioned medium of COLO 205 and HT 1080 cells by immunoaffinity chromatography. According to its aminoterminal amino acid sequence, a molecular mass of 28 kDa by SDS-PAGE, elution pattern in ion-exchange chromatography and ability to be activated by enteropeptidase, the zymogen is identical to that previously isolated from cyst fluid of ovarian tumors. In addition, we found that TAT-2 secretion could be down-regulated by dexamethasone in HT 1080 cells but not in COLO 205 cells. The abundant production of TAT-2 isoenzyme in different cancer cell lines suggests that it could contribute to the increased proteolytic activity of many human tumors.
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PMID:Human colon carcinoma, fibrosarcoma and leukemia cell lines produce tumor-associated trypsinogen. 199 87

We have recently demonstrated that many cancer cell lines produce a novel trypsinogen isoenzyme called tumor-associated trypsinogen 2 (TAT-2). It was found during a search of the target protease for tumor-associated trypsin inhibitor (TATI). We now show that degradation of subendothelial cell extracellular matrix (ECM) by four different cell lines (COLO 205 colon carcinoma, K-562 erythroleukemia, CAPAN-1 pancreatic carcinoma, and HT 1080 fibrosarcoma) can be partially inhibited by TATI or neutralizing trypsin antibodies. When cells were cultured in serum-free medium on ECM, TATI and trypsin antibodies inhibited the release of immunoreactive fibronectin fragments from ECM by 47-54 and 40%, respectively. Degradation of isotopically labeled ([3H]serine, [3H]proline, and [35S]sulfate) ECM was also significantly prevented by TATI. At its maximum, it exerted a 57% inhibition on the degradation of [3H]serine-labeled ECM. Plasminogen added exogenously to the culture medium further potentiated the proteolysis of ECM. Interestingly, addition of enteropeptidase, an activator of TAT-2, also enhanced cell-mediated proteolysis as assessed by degradation of purified fibronectin coated onto the surface of wells. Immunoblot analysis showed that enteropeptidase-mediated proteolysis generated a pattern of fibronectin fragments similar to that obtained by digestion of purified fibronectin by TAT-2. These results demonstrate the existence of a proteolytic system in tumor cells which is dependent on the activation of TAT-2. We suggest that TAT-2 is involved in a protease cascade-stimulating tumor cell invasion and degradation of extracellular matrix.
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PMID:Tumor-associated trypsin participates in cancer cell-mediated degradation of extracellular matrix. 200 30