PTEN tumor suppressor gene combined with doxycycline inhibites telomerase activity in human mucoepidermoid carcinoma cell line / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the effect of PTEN tumor suppressor gene combined with doxycycline on telomerase activity in human mucoepidermoid carcinoma cell line.</p><p><b>METHODS</b>The wild-type PTEN tumor suppressor gene or empty vector was introduced into mucoepidermoid carcinoma cell line in vitro, then the cancer cells were treated with doxycycline. Cancer cell survival was determined by MTT assay. Telomerase activity was determined using telomerase repeat amplification protocol-enzyme-linked immunosorbent assay (TRAP-ELISA).</p><p><b>RESULTS</b>Compared to the control cells, cancer cells transfected with the wild-type PTEN gene showed growth inhibition and increased sensitivity to doxycycyline, and the ratio of augment of drug sensitivity was 1.65-4.75. The telomerase activity in cancer cells treared with PTEN gene transfection or doxycycline alone decreased, however, telomerase activity in combined group decreased more remarkably.</p><p><b>CONCLUSION</b>PTEN gene in combination with doxycycline has significant inhibitory effect on telomerase activity in cancer cells.</p>

The inhibition of fragile histidine triad gene on the proliferation and tumorigenicity of mucoepidermoid carcinoma cells / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the suppression effect of exogenous fragile histidine triad (FHIT) gene on biological property of MEC-1 cells.</p><p><b>METHODS</b>In order to study the FHIT function in MEC-1 cells, wild-type FHIT gene was transferred into mucoepidermoid carcinoma MEC-1 cells. The proliferation and kinetics, cell cycle, clonal forming rate, and apoptosis of MEC-1 cells, before and after FHIT gene transfection in vitro, and tumor loci formed on mice after injection of transferred MEC-1 cells in vivo were observed by immunochemical staining, flow cytometry analysis, and so on.</p><p><b>RESULTS</b>It can be seen that exogenous FHIT gene transfer could significantly inhibit the proliferation and reduce the kinetics of MEC-1 cells in vitro, prolong DT from (21.03+/-0.41) h to (26.86+/-0.71) h, and also keep less cells in cell cycle phase S, whilst more cells in phase G1, Additionally, the exogenous FHIT was found to be able to remarkably suppress MEC-1 cells of forming tumor loci in nude mice by lessen tumor weight, and promote higher differentiation of MEC-1 cells to be mucous cells.</p><p><b>CONCLUSION</b>Exogenous FHIT gene could suppress the proliferation, tumorigenicity and improve the differentiation of MEC-1 cells, in vitro and in vivo.</p>

Construction of eukaryotic expression vector of short hairpin RNA for transforming growth factor-beta1 / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To construct the plasmid containing short hairpin RNA (shRNA) of TGF-beta1 expression vector.</p><p><b>METHODS</b>Short chain oligonucleotide was designed according to the TGF-beta1 mRNA sequence provided by Genebank, then DNA segment was gained through annealing after chemosynthesis, and then was cloned to pWH1 vector. The recombinant TGF-beta1 shRNA expression vector was evaluated by using enzyme cutting. At last, the constructed TGF-beta1 expression vector was transfected into salivary gland mucoepidermoid carcinoma (Ms) cells by Lipofectomine TM 2000, and its effect on TGF-beta1 expression was observed by RT-PCR and immunohistochemistry.</p><p><b>RESULTS</b>Successful construction was identified by enzyme cutting and the constructed plasmid was called pWH1-TGF-beta1. The shRNA and it inhibited the TGF-beta1 mRNA and protein expression effectively.</p><p><b>CONCLUSION</b>The constructed TGF-beta1 shRNA expression vector can block the TGF-beta1 expression in salivary gland mucoepidermoid carcinoma cells.</p>

Screening and identification of metastasis-related gene expression in tongue carcinoma with cDNA microarray assay / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To identify metastasis-associated genes in tongue carcinoma and to better understand the mechanism underlying tongue carcinoma metastasis. To compared mRNA expression profiles of two tongue carcinoma cell strains with high and low metastatic potentials using microarray technology.</p><p><b>METHODS</b>Tca8113 and Tb cells were used as model systems to study the molecular mechanism of tumor metastasis. Two fluorescent cDNA probes labeled with Cy3 and Cy5 dyes were prepared from the mRNA samples of Tca8113 and Tb cells by reverse transcription method. The two color probes were then mixed and hybridized to the cDNA chip constructed by double dots of 1 152 human genes, and scanned at two wave lengths. Differential expression genes from the above two cell lines were analyzed using computer. Then six of the different expression genes were further validated by RT-PCR technique.</p><p><b>RESULTS</b>In the 1 152 clones of known genes and expressed sequence tags that were analyzed, 37 showed significantly different (minimum 2 folds) expression levels in two cell lines. Among the 37 genes, 15 were up regulated (with ratio more than 2) and 22 down regulated (with ratio less than 1/2). The results of RT-PCR analysis were coincident with those of microarray assay.</p><p><b>CONCLUSION</b>Some of these genes are known to be involved in human tumor antigen, immune surveillance, adhesion, cell signaling pathway and growth control. It is suggested that the microarray in combination with a relevant analysis facilitates rapid and simultaneous identification of multiple genes of interests and in this study it provided a profound clue to screen candidate targets for early diagnosis and intervention.</p>

Effects of 17 beta-estradiol on the adhesion, invasion and motility potential of salivary mucoepidermoid carcinoma Mc3 cells / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To study the effects of 17 beta-estradiol on the adhesion, invasion and motility potential of salivary mucoepidermoid carcinoma Mc3 cells.</p><p><b>METHODS</b>The effects of 17 beta-estradiol on adhesion, invasion and motility potential of salivary mucoepidermoid carcinoma Mc3 cells were investigated with cell attachment assay on fibronectin (FN), wound assay, chemotaxis assay, and gelatin-incorporated SDS-PAGE electrophoresis. The expression of estrogen receptor in Mc3 cells was determined by immunohistochemistry assay.</p><p><b>RESULTS</b>Attachment rates of Mc3 cells treated with E2 at 10(-9), 10(-8), 10(-7), 10(-6) mol/L were 38.3%, 50.4%, 69.2% and 91.1% respectively, and the rate in control was 25.0%. When exposed to 17 beta-estradiol at 10(-9), 10(-8), 10(-7) and 10(-6) mol/L for 48 h, motility of Mc3 cells on FN increased by 16.9%, 40.9%, 36.4% and 38.8% respectively. When at 10(-6) mol/l, 17 beta-estradiol increased chemotaxis potential of Mc3 cells to FN by 60.3%. The activity of 68 000 matrix metalloproteinase (MMP-2) of Mc3 cells was enhanced at different levels by 10(-9), 10(-8), 10(-7), 10(-6) mol/L of 17 beta-estradiol, and estrogen receptor was also detected in nucleus of Mc3 cells by immunohistochemistry assay.</p><p><b>CONCLUSIONS</b>17 beta-estradiol at physiological concentration may enhance the adhesion, invasion and motility potential of salivary mucoepidermoid carcinoma Mc3 cells.</p>

Improvement of osseointegration of titanium dental implants by a modified sandblasted surface / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To study effects of the modified sandblasted surface of titanium implants, developed by authors, on the bone healing process.</p><p><b>METHODS</b>Osteoblasts were derived from the 5th passage of human fetal osteoblasts after primary isolation. Alkaline phosphatase (ALP) activities and protein contents of cellular layers, and osteocalcin contents in culturing medium were employed as criteria to evaluate osteogenic functions and differentiation of osteoblasts. The ALP activity was assayed utilizing the kinetic method, the protein content utilizing the Coomassie's method, and the osteocalcin content utilizing the radioimmune assay (RIA) method. Values of all criteria were divided by the corresponding cell numbers of different groups at a respective time point for the purpose of standardization. Samples were assigned to three groups-the modified sandblasted surface group, the smooth surface group and the blank control group, The culture was ended at, 4 days and 13 days.</p><p><b>RESULTS</b>At 4 days of culture, the modified sandblasted surface group showed a superiority to the smooth group with respects to the ALP activity [(17.390 +/- 1.595) nmol PNP x min(-1) x 10(-6) cells vs. (10.978 +/- 1.879) nmol PNP x min(-1) x 10(-6) cells] and protein content [(152.7 +/- 16.3) micro g/10(6) cells vs. (58.0 +/- 5.9) micro g/10(6) cells] of cellular layers and the osteocalcincontent [(43.0 +/- 6.1) ng/10(6) cells vs. (24.9 +/- 6.0) ng/10(6) cells] in culturing medium. Till the 13th day of culture, no differences were detected.</p><p><b>CONCLUSIONS</b>It is cytologically proved that the modified sandblasted surface can accelerate the bone healing process of implants though the improvement of osteoblastic functions and differentiation.</p>