Association of matrix metalloproteinase-2 activity with cell proliferation and growth in ameloblastoma / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the relationship between matrix metalloproteinase-2 (MMP-2)activity and cell proliferation, growth and invasion of ameloblastoma.</p><p><b>METHODS</b>The cells and xenograft of ameloblastoma were treated with MMP-2 inhibitor Ro31-9790 and the effects of Ro31-9790 on the cell proliferation and growth of ameloblastoma were observed. Primary culture in vitro, subcapsular kidney xenograft in vivo, MTT assay, flow cytometry, neoplastic volume measurement and histochemistry were employed to study the effects of cell proliferation and growth produced by Ro31-9790.</p><p><b>RESULTS</b>There was no significant different in cell proliferation at same interval among several groups (P > 0.05). The ratio of G0/G1 stage, G2/M stage and apoptotic cells didn't increase following increased Ro31-9790, and the ratio of S stage cells also didn't reduce following increased Ro31-9790. The tumor volume and its increase in treatment group were significant less than those in control group.</p><p><b>CONCLUSION</b>Ro31-9790 does not influence proliferation of ameloblastoma cells in vitro, but it can effectively inhibit the ameloblastoma growth in vivo. MMP-2 activity has no relationship to proliferation of ameloblastoma cells, but it can contribute to the ameloblastoma growth and may be a reason of invasion in ameloblastoma.</p>

Synthetic radiation-inducible promoter mediated CDglyTK gene in treatment of Tca8113 cells / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To observe the therapeutic effect of CDglyTK gene mediated by synthetic radiation-inducible promoter in the treatment of Tca8113 cells.</p><p><b>METHODS</b>CDglyTK gene in pCEA-CDglyTK was subcloned into pcDNA3.1 (+) to construct plasmid pcDNA3.1 (+)-CDglyTK, and then the synthetic radiation-inducible promoter in pMD18 -T -E was inserted into pcDNA3.1 (+) -CDglyTK to construct plasmid pcDNA3.1 (+ )/E -CDglyTK. The recombinant plasmid was transfected into Tca8113 cells by lipofectamine, and then exposed to 3 Gy irradiation. Cytotoxicity was evaluated by MTT. The expression of CDglyTK gene was detected by RT-PCR. The apoptosis and proliferation were examined by flow cytomtery.</p><p><b>RESULTS</b>The plasmid pcDNA3.1 (+)/E-CDglyTK was constructed successfully. The comparative survival rate of Tca8113 cells was markedly decreased by induction irradiation. Up-regulation of CDglyTK expression was found in Tca8113 cells exposed to irradiation. The apoptosis index (AI) of Tca8113 cells exposed to irradiation was higher than that of Tca8113 cells without irradiation, the other way round, the proliferation index (PI) of Tca8113 cells exposed to irradiation was lower than that of Tca8113 cells without irradiation.</p><p><b>CONCLUSION</b>The synthetic radiation-inducible promoter can be served as a molecular switch to improve the expression of CDglyTK gene in Tca8113 cells, and low dose induction radiation can significantly improve the therapeutic efficiency.</p>

Construction and selection of siRNA expression cassettes targeting human telomerase reverse transcriptase gene in vitro / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To determine whether the human telomerase reverse transcriptase (hTERT) gene silencing could be effectively induced by PCR-derived siRNA expression cassettes (SEC) transfected by the fifth generation polyamidoamine dendrimer (G5 PAMAM-D) in Tca8113 cells.</p><p><b>METHODS</b>Four SEC were rationally designed and constructed based on a two-step PCR reaction. The SEC were then transferred into Tca8113 cells using G5 PAMAM-D, and hTERT expression was investigated by real-time fluorescence-quantitative reverse transcriptase-PCR and western blot analysis.</p><p><b>RESULTS</b>The RNA interference effects of the SEC targeted for varying hTERT mRNA positions showed a significant disparity. Among them, SEC-A revealed the most potent inhibitory effects (above 95% of reduction), followed by SEC-D and SEC-C, and SEC-B had no effect on hTERT expression (P > 0.05). That the endogenous hTERT gene silencing induced by G5 PAMAM dendrimer-mediated SEC-A was highly sequence-specific, and multiple transfection as well as properties of the vectors were routinely attributable to the specific suppression.</p><p><b>CONCLUSIONS</b>Specific inhibition of endogenous hTERT expression by use of a PCR-based short hairpin siRNA technique and dendrimer transfer system may serve as a novel strategy for treatment of tongue cancers expressing hTERT in vitro.</p>

Radiation-inducible promoters-mediated cdglytk gene in the treatment of buccal carcinoma in golden hamster / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To observe the therapeutic effect of CDglyTK gene mediated by radiation-inducible promoters in the treatment of buccal carcinoma in Golden Hamster.</p><p><b>METHODS</b>Animal models of buccal carcinoma in golden hamster were established by painting 0.5% dimethyl-benzanthracene. The plasmids pcDNA (+) 3.1/E-CDglyTK were transfected into tumors by lipofectamine. 24 h later, the tumors were exposed to 3 Gy irradiation. Animals were monitored at regular intervals for volume of tumors. CDglyTK mRNA was assayed by RT-PCR. Apoptosis and proliferating cell nuclear antigen were detected respectively by in situ end-labeling and immunohistochemical methods.</p><p><b>RESULTS</b>Compared with control groups, the tumor was suppressed obviously by CDglyTK gene therapy combined with 3 Gy induction radiation. The expression of CDglyTK gene could be detected by RT-PCR in the transfected tumor, and up-regulation of CDglyTK expression was found in tumor exposed to radiation (P < 0.05). There was significant difference in apoptosis index or proliferation index between tumor without irradiation and tumor with irradiation (P < 0.05).</p><p><b>CONCLUSIONS</b>The radiation-inducible promoter can be served as a molecular switch to regulate the expression of CDglyTK gene in buccal carcinoma in golden hamster, and low dose induction radiation can significantly improve the therapeutic effects.</p>

Dynamic observation of lung metastasis model of adenoid cystic carcinoma / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To form ACC-M-GFP cells by transfecting pEGFP-1 into ACC-M cells, and to build up lung metastasis model of adenoid cystic carcinoma for dynamic observation in simulated lung environment.</p><p><b>METHODS</b>pEGFP-1 was prepared and then transfected into ACC-M cell lines by using cationic lipid-based gene transfer technique. After successive selection, the ACC-M-GFP cells were collected and inoculated in BALB/C mice. The simulated lung environment was built up, and dynamic observation was performed by laser confocal microscopy within four weeks after transfection.</p><p><b>RESULTS</b>The amount of fluorescent tumor cell colonies and the intensity of fluorescence gradually increased from the second week to the forth week after transfection. In the meantime, only a very small number of tumor cells had the ability to form clones.</p><p><b>CONCLUSIONS</b>We successfully built up a lung metastasis model of adenoid cystic carcinoma for dynamic observation. The model is suitable for capturing and analyzing metastatic tumor cells in early stage.</p>