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@#ObjectiveTo investigate the role of platelet-derived growth factor(PDGF) and its receptor in the development of hypertrophic scar. MethodsThe expression of PDGF and its receptor were detected in biopsy specimens of 9 pieces of normal skin, 7 pieces of granulation tissue of burn wound and 34 pieces of hypertrophic scar by immunohistochemical staining using specific polyclonal antibodies.ResultsPDGF and its receptor markedly increased in granulation tissue and hypertrophic scars, reaching the peak in the hypertrophic scars within 6 months and then decreased after the peak, whereas PDGF and its receptor expressed weakly in only a few normal skin specimens, and the differences were significant(P<0.05).ConclusionsThe increasing expression of PDGF and its receptor may be related to the development of hypertrophic scar.
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AIM: To investigate the inhibitory effect of vector-based RNA interference(RNAi) on the expression of melanoma associated antigen A3(MAGEA3) protein in hepatocellular carcinoma cells and on apotposis of hepatocellular carcinoma cells.METHODS: A vector for transcribing specific small hairpin RNA(shRNA) targeting MAGEA3 gene was constructed,introduced into hepatocellular carcinoma MEL-ED1 cells by Lipofectamine 2000.The MAGEA3 protein and mRNA expression levels of MEL-ED1 cells were detected by Western blotting and RT-PCR, respectively.The cell apoptosis was studied by DNA fragmentation,electron microscopy,TUNEL assay,and annexin V/PI staining.RESULTS: The vector of RNA interference was successfully constructed and MAGEA3 expression was descreased significantly in MEL-ED1 cells.After the shRNA expression vector was transfected into the MEL-ED1 cells,the expression of MAGEA3 gene was inhibited significantly(by 90%).DNA fragmentation,electron microscopy and TUNEL assay showed classic apoptosis characters in the MEL-ED1 cells transfected with pSilencer-MAGEA3 plasmid with an apoptosis rate of 21.41% ?1.98%,significantly higher than those in the negative control group transfected with pSilencer-neo and in the non-transfected group(both P
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AIM: To study effects of urokinase-type plasminogen activator (uPA) signal transduction on expression of matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of matrix metalloproteinase-3 (TIMP-3) in giant cell tumor of bone (GCT). METHODS: Expression of uPAR, MMP-2 and TIMP-3 in GCT tissue was detected by immunohistochemistry. Phosphorylation level of mitogen-activated protein kinase (p44) in uPA/uPAR signal pathway in cultured GCT cells was detected by immunoprecipitation. The expression of MMP-2 and TIMP-3 in cultured cells after treatment with uPA-ATF or anti-uPAR antibody was also detected by Western blotting. RESULTS: 1) Urokinase-type plasminogen activator receptor (uPAR) was positive on the cell membrane and in cytoplasm of some mononuclear stromal cells (MSCs) and multinucleated giant cells (MGCs); 2) MMP-2 was positive in the cytoplasm and on the cell membrane of almost all of MSCs and some of MGCs. The polar distribution of MMP-2 in the cytoplasm of MGCs was especially obvious; 3) The expression of TIMP-3 of some MSCs and MGCs in GCT was much lower than MMP-2. The positive signal also showed a prominent polarity; 4) After treatment with uPA-ATF, the phosphorylation level of p44 in GCT cultured cells was much higher than the control. Addition of anti-uPAR antibody in the cells remarkably down-regulated the phosphorylation level of p44 as compared with the control group, suggesting that uPA-ATF participates cell signal transduction and this reaction can be inhibited by anti-uPAR antibody; 5) uPA-ATF cell signal pathway up-regulated expression of MMP-2 and TIMP-3, while anti-uPAR antibody down-regulated the expression of MMP-2 and TIMP-3. CONCLUSION: These results demonstrate for the first time that uPA-ATF directly regulates the expression of MMP-2 and TIMP-3 by signal transduction pathway, and the over-expression of MMP-2 and TIMP-3 may play an important role in local osteolysis of GCT. [
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AIM: To investigate whether protein kinase C (PKC) is involved in the proliferation and the telomerase expression in human hepatocellular carcinoma cells. METHODS: Human hepatocellular carcinoma cells (BEL-7402) were treated with exogenous phorbol-12-myristate-13-acetate (PMA, PKC activator) and staurosporine (SP, PKC inhibitor) for 48 hours. The techniques of cell culture and the telomeric repeat amplification protocol silver staining in combination with computer image scanning system in vitro were used to observe the variations of the growth and the telomerase expression. RESULTS: The proliferative potential of BEL-7402 cells was decreased by the action of PMA as well as SP, and the telomerase expression was also inhibited by PMA and SP. CONCLUSION: Our findings suggest that the proliferation of human hepatocellular carcinoma cells and the telomerase expression may be related to PKC. [