Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.1.1.69 (BMT)
 2,655 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A weakly tumorigenic cell clone (QR-32) derived from a murine fibrosarcoma (BMT-11) grew lethally in 6 out of 10 syngeneic C57BL/6 mice after co-implantation with gelatin sponge. All six cell lines (QRsP) established from the arising tumors from QR-32 had enhanced tumorigenicity and/or pulmonary metastatic ability in vivo, indicating that those QRsP cell lines acquired progressed phenotypes as compared with those of QR-32 cells. In contrast, the frequency of tumor progression was suppressed to 50% (3/6) in the cell lines (QRsP/PSK) established from those arising in the mice treated with an immunopotentiating protein-bound polysaccharide, PSK. The enhanced metastatic ability was accompanied by enhanced expressions of a tumor-associated transcription factor, E1AF and by increased production of matrix metalloproteinase (MMP) in five lines of QRsP and two lines of QRsP/PSK. It was found that administration of PSK augmented the production of an antioxidative enzyme, manganese superoxide dismutase (Mn-SOD), in the tumor tissues co-implanted with gelatin sponge. PSK administration also brought about up-regulation of interferon-gamma (IFN-gamma)-expression and down-regulation of transforming growth factor-beta (TGF-beta)-expression in the tumor tissues, which were examined by RT-PCR on day 7, 14 and 21 after the co-implantation. Other inflammatory cytokines such as interleukin-1 alpha (IL-1 alpha) and tumor necrosis factor-alpha (TNF-alpha) were expressed equally both in PSK-treated and untreated tumor tissues. In vitro experiments proved that although IFN-gamma did not increase the production of Mn-SOD by itself, concomitant treatment with both IFN-gamma and TNF-alpha enhanced the Mn-SOD-production in QR-32 cells greatly. On the contrary, TGF-beta treatment lowered the Mn-SOD level in QR-32 cells. PSK-treatment did not induce Mn-SOD in cultured QR-32 cells directly. These results indicated that PSK inhibits the malignant progression of QR-32 cells promoted by co-implantation with gelatin sponge, most possibly through elevating the Mn-SOD level in QR-32 cells via modulation of the production of inflammatory cytokines, that is, increasing IFN-gamma and decreasing TGF-beta at the site of tumor growth.
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PMID:[Induction of manganese superoxide dismutase by an immunopotentiator as a mechanism of inhibiting of malignant progression of murine tumor cells]. 984 81

We isolated six clones of weakly tumorigenic fibrosarcoma (QR) from the tumorigenic clone BMT-11 cl-9. The QR clones were unable to grow in normal C57BL/6 mice when injected s.c. (1x10(5) cells). However, they formed aggressive tumours upon co-implantation with a 'foreign body', i.e. a gelatin sponge, and the rate of tumour take ranged from 8% to 58% among QR clones. The enhanced tumorigenicity was due to host cell-mediated reaction to the gelatin sponge (inflammation). Immunoblot analysis and enzyme activity assay revealed a significant inverse correlation between the frequencies of tumour formation by QR clones and the levels of manganese superoxide dismutase (Mn-SOD, P<0.005) and glutathione peroxidase (GPchi, P<0.01) in the respective tumour clones. Electron spin resonance (ESR) revealed that superoxide-scavenging ability of cell lysates of the QR clone with high level of Mn-SOD was significantly higher than that with low level of the antioxidative enzyme in the presence of potassium cyanide, an inhibitor for copper-zinc superoxide dismutase (CuZn-SOD) (P<0.001). Minisatellite mutation (MSM) induced by the inflammatory cells in tumour cells were investigated by DNA fingerprint analysis after QR clones had been co-cultured with gelatin-sponge-reactive cells. The MSM rate was significantly higher in the subclones with low levels of Mn-SOD and GPchi (P<0.05) than in the subclones with high levels of both enzymes. The MSM of the subclones with low levels of both enzymes was inhibited in the presence of mannitol, a hydroxyl radical scavenger. The content of 8-hydroxydeoxyguanosine (8-OHdG) by which the cellular DNA damage caused by active oxygen species can be assessed was significantly low in the tumours arising from the QR clone with high levels of Mn-SOD and GPchi even if the clone had been co-implanted with gelatin sponge, compared with the arising tumour from the QR clone with low levels of those antioxidative enzymes (P<0.001). In contrast, CuZn-SOD and catalase levels in the six QR clones did not have any correlation with tumour progression parameters. These results suggest that tumour progression is accelerated by inflammation-induced active oxygen species particularly accompanied with declined levels of intracellular antioxidative enzymes in tumour cells.
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PMID:Inflammatory cell-mediated tumour progression and minisatellite mutation correlate with the decrease of antioxidative enzymes in murine fibrosarcoma cells. 1002 2