[Changes of oral bacteria flora after wearing complete denture].

PURPOSE: This study investigateed the influence of complete denture on oral bacteria flora. METHODS: Bateria plaque samples in oral mucosa, saliva and denture surfaces in 11 edentulous patients were collected, then the 16S rRNA gene clone libraries were constructed. Pyrosequencing was used to analyze the 16S rRNA gene V3~V4 regions, oral bacteria flora were classified and identified. RESULTS: There were 64800 sequences in complete denture-wearing subjects, Streptococcus mitis, Gemella haemolysans, Rothia mucilaginosa, Porphyromonas sp, Neisseria zoodegmatis, Granulicatella elegans, Acinetobacter baumannii, Pseudomonas citrinum, Granulicatella adiacens and Fusobacterium canifelinum were the predominant species (37416 sequences). The species of denture tissue surface were similar to these of buccal vestibule after wearing denture, and the species of denture smooth surface were similar to these of tongue ventrum and the floor of mouth. CONCLUSIONS: The effect of complete denture on oral flora is still limited, and the composition of oral flora is influenced by many other factors.

Human Papillomavirus 16 Infection and TP53 Mutation: Two Distinct Pathogeneses for Oropharyngeal Squamous Cell Carcinoma in an Eastern Chinese Population.

OBJECTIVES: To investigate the clinicopathological characteristics, human papillomavirus (HPV) infection, p53 expression, and TP53 mutations in oropharyngeal squamous cell carcinoma (OPSCC) and determine their utility as prognostic predictors in a primarily eastern Chinese population. METHODS: The HPV infection status was tested via p16INK4A immunohistochemistry and validated using PCR, reverse blot hybridization and in situ hybridization (ISH) in 188 OPSCC samples. p53 expression levels and TP53 gene mutations were assessed through immunohistochemistry and sequencing, respectively. Clinicopathological characteristics and follow-up information were collected. Overall survival was estimated using the Log-rank test. RESULTS: Overall, 22 of the 188 OPSCC samples were associated with HPV infection. HPV16 was identified in all 22 samples, whereas no samples were positive for HPV18. All 22 HPV-associated OPSCC samples were p53 negative and lacked TP53 mutations. HPV16 positivity, female patients, non-smokers, and patients with histological grade I and stage N0 diseases showed better overall survival (p = 0.009, 0.003, 0.048, 0.009, and 0.004, respectively). No significant differences in overall survival between smoking and non-smoking patients were observed in the HPV-associated OPSCC group. Patients without mutations in TP53 exons 5-8 had better prognoses (p = 0.031) among the 43 sequenced specimens. Multivariate analysis indicated that HPV16 infection status (p = 0.011), histological grade (p = 0.017), and N stage (p = 0.019) were independent prognostic factors for patients with OPSCC. CONCLUSIONS: Distinct from the situation in Europe and America, for the patients with OPSCC in this study, HPV16 infection was relatively low, although it was still the most important independent prognostic predictor for the disease. In addition to the high smoking and drinking rate in this population, HPV16 infection and TP53 dysfunction appear to be two distinct pathogens for OPSCC patients in the eastern Chinese population.

[Expression and clinical significance of plasma microRNA-125b level in patients with oral squamous cell carcinoma].

PURPOSE: To explore the expression and clinical significance of plasma microRNA-125b (miR-125b) in patients with oral squamous cell carcinoma (OSCC). METHODS: By Stem-loop RT real-time PCR based on the SYBR Green, we investigated the expression of plasma miR-125b in 85 OSCC patients and 46 healthy controls, then evaluated its diagnostic performance as OSCC biomarker. Data analysis was performed with SPSS 17.0 software package for one-way ANOVA and receiver operating characteristic (ROC) curve. RESULTS: Stem-loop RT-PCR could specifically amplify miR-125b in plasma. The expression of plasma miR-125b was significantly increased in patients with OSCC compared with healthy controls (P<0.05). ROC results showed that miR-125b could differentiate OSCC from healthy controls(AUC=0.966). As fold change 3.46 was chosen for optimal cutoff value, the diagnostic sensitivity and specificity was 89.4% and 93.5%, respectively. CONCLUSIONS: Due to the satisfactory diagnostic performance, plasma miR-125b can be used as a promising biomarker in OSCC.

Overexpression of c-fos promotes cell invasion and migration via CD44 pathway in oral squamous cell carcinoma.

BACKGROUND: Oral squamous cell carcinoma (OSCC) is one of the most deadly malignant tumors with high invasive potential and frequently cervical lymph node metastasis. AP-1 plays a critical role in tumor invasion and metastasis, but there are few reports on the role of c-Fos in OSCC carcinogenesis and metastasis. METHODS: Investigate c-Fos expression in clinical samples from 58 primary patients with OSCC by immunohistochemistry. c-Fos knockdown stable cell lines were established by lentiviral infection and transwell cell invasion assay to detect the effects of c-Fos knockdown on tumor cell invasion. RESULTS: Nuclear and cytoplasmic c-Fos protein were both overexpression in cancerous tissues compared with adjacent non-malignant epithelia (nuclear: P < 0.001, cytoplasmic: P = 0.005). Higher level nuclear c-Fos expression was found in the tumor samples of patients with lymph node metastasis than those without lymph node metastasis (4.85 ± 1.43 vs. 3.61 ± 1.28, P = 0.002). Higher level of c-Fos expression was also found in tumor invasive front margin than tumor center and high nuclear expression of c-Fos indicated poor survival. Knockdown of c-Fos greatly suppressed tumor cell proliferation and invasion and downregulated CD44 and CyclinD1 expression in HN6 and SCC9 cells. However, CyclinD3, c-myc, and Erk1/2 were found no changes to c-Fos depletion. CONCLUSIONS: c-Fos promoted cell invasion and migration via CD44 pathway in OSCC. c-Fos could be used as a potential therapeutic target gene and an additional marker for evaluation of lymph node metastasis.

Repression of G protein-coupled receptor family C group 5 member A is associated with pathologic differentiation grade of oral squamous cell carcinoma.

BACKGROUND: G protein-coupled receptor family C group 5 member A (GPRC5A), a member of G protein-coupled receptor family, has been shown to function as a tumor suppressor in lung tissue. The biological functions of GPRC5A have therefore been linked to lung tissue. However, the biological significance of this gene product remains obscure. In this study, we investigated the expression of GPRC5A proteins in normal oral tissue and oral squamous cell carcinoma (OSCC), and we characterized its biological activity in OSCC cell lines. METHODS: Western blot analysis and immunohistochemical staining were used to investigate the expression of GPRC5A in both OSCC cell lines and clinical samples. GPRC5A stable transfectants and their parental OSCC cells were characterized for their biological activities in anchorage-independent growth. RESULTS: High levels of immunohistochemical GPRC5A expression were detected in normal oral tissue, especially differentiated area. In contrast, GPRC5A expression was dramatically repressed in OSCCs (P < 0.01). The immunohistochemical GPRC5A expression was moderately well differentiated, but greatly repressed in moderately differentiated OSCCs and completely repressed in poorly differentiated OSCCs. Overexpression of GPRC5A in OSCC CAL27 cells resulted in a suppressed anchorage-independent growth activity, a transforming phenotype. CONCLUSIONS: GPRC5A is expressed in normal oral epithelium. Repression of GPRC5A is associated with poorly differential grade of OSCCs. Overexpression of GPRC5A in OSCC cell line reversed the malignant phenotype. Thus, GPRC5A is important for homeostasis in oral tissue, and deletion or repression of this gene may involve in tumorigenesis of OSCCs and may serve as a prognostic marker for malignant type of OSCCs.

Upregulation of ß2-microglobulin expression in progressive human oral squamous cell carcinoma.

The aim of the present study was to investigate ß2-microglobulin (ß2-M) expression in normal oral mucosa and progressive oral squamous cell carcinoma (OSCC) and to assess the clinical significance of ß2-microglobulin expression. The study included 10 cases of normal oral mucosa epithelium specimens, 55 cases of primary OSCC specimens, and 25 cases of OSCC metastasis specimens. Immunohistochemistry was used to determine ß2-M expression, and its correlation with clinicopathological factors in progressive OSCC was evaluated. Immunohistochemistry showed that strong ß2-M expression was significantly asscociated with tumor size (T3, T4 vs. T1, T2; P=0.001), positive node status (N positive vs. N negative; P=0.000) and advanced clinical stage (Ⅲ, Ⅳ vs. Ⅰ, Ⅱ, P=0.000) in primary OSCC lesions. Compared to primary OSCC lesions, the frequency of ß2-M expression was significantly increased in metastatic OSCC lesions (P=0.02). In addition, in vitro results from Western blotting showed increased ß2-M expression in the two OSCC lines studied. Therefore, we speculate that the up-regulation of ß2-M expression may contribute to the oncogenesis of human oral mucosa, tumor invasion and metastasis.

[Effect of compound Chinese traditional medicine on periapical periodontitis in dogs and cytotoxic assay].

PURPOSE: To assess the efficacy of compound Chinese traditional medicine(CTM), which is composed of gallic acid, magnolol and polysaccharide of Bletilla, against apical periodontitis in dogs and cytotoxic assay. METHODS: A animal model of apical periodontitis was built, CTM was then used to disinfect the root canal. The effect of the restoration of periapical bone in dogs was investigated after regular root canal filling. SAS6.12 software package was used for statistical analysis, and MTT was used to test cell toxicity of CTM. RESULTS: CTM can cure inflammation effectively, and CTM had no cytotoxic effect on periodontal ligament cells at 5-week. CONCLUSIONS: The compound Chinese traditional medicine may be an effective disinfecting drug for root canal disinfection.

[Expression of galectin-1 in carcinogenesis of oral mucosal epithelium].

OBJECTIVE: To investigate the expression of galectin-1 in oral squamous cell carcinoma(OSCC) and its clinical significance. METHODS: Detection of the mRNA and protein expression of galectin-1 in the in vitro cellular carcinogenesis model of OSCC, OSCC cell lines and tissue specimens from 30 primary OSCC patients were performed using real-time polymerase chain reaction (PCR), Western blotting and immunohistochemistry, respectively. RESULTS: The value of galectin-1 mRNA and protein level in human immortalized oral epithelia cell (HIOEC) cell was 0.071 ± 0.023, 0.118 ± 0.046, Compared with the HIOEC, galectin-1 mRNA level and protein expression were increased significantly in all the cell lines (0.141 ± 0.049, 0.504 ± 0.33) (P < 0.01). The levels of mRNA and protein expression of galectin-1 were significantly higher in the cancerous tissue (0.059 ± 0.034, 1.5 ± 0.68) than in the normal adjacent tissues (0.029 ± 0.012, 0.4 ± 0.56) (P < 0.01). CONCLUSIONS: The expression of galectin-1 gene up-regulated in carcinogenesis process of OSCC significantly may be related to the tumorigenesis and development of OSCC, which illustrates its potential clinical application as tumor marker for early diagnosis.

Yes-associated protein promotes cell proliferation by activating Fos Related Activator-1 in oral squamous cell carcinoma.

In our previous study, we established an in vitro cellular carcinogenesis model of oral squamous cell carcinoma (OSCC), including a human immortalized oral epithelial cell (HIOEC) and a cancerous cell line (HB96). Microarray analysis showed that the gene encoding Yes-associated protein (YAP) was significantly increased in HB96 cells compared with HIOEC cells. But the underlying mechanism of YAP on oncogenesis, especially its downstream targets, are still not clear. YAP expression in OSCC cell lines and tissue specimens were investigated by using real-time PCR, western blotting and immunohistochemistry staining. YAP put-back plasmid with four mutation sites after YAP-siRNA interference was constructed by site-directed mutagenesis. Cell growth and colony formation were observed after YAP-siRNA interference or YAP put-back again in CAL27 cells. YAP expression was increased in the cellular carcinogenesis models and the clinical samples from primary OSCC patients. Inhibition of YAP by siRNA interference in CAL27 cells significantly inhibited cell proliferation and colony formation in soft agar, but these abilities were rescued when YAP was put-back again. At the same time, Fos Related Activator-1 (Fra-1) was down-regulated when YAP was inhibited by siRNA interference while Fra-1 was rescued when YAP was put-back again. Immunohistochemistry results also indicated that higher levels of YAP were significantly associated with Fra-1 overexpression in OSCC clinical samples. YAP could promote cell proliferation by activating transcription factor Fra-1 in oral squamous cell carcinoma.

[Effect of compound Chinese traditional medicine on infected root canal bacteria biofilm].

PURPOSE: To assess the efficacy of compound Chinese traditional medicine(CTM), which composed of gallic acid, magnolol and polysaccharide of Blettila striata, against the infected root canal bacterial biofilm. METHODS: Actinomyces viscosus (Av), Enterococcus faecalis (Ef), Fusobacterium nucleatum (Fn) were composed to form biofilm, then confocal laser scan microscope (CLSM) was used to observe and study the bacterial activity. SAS6.12 software package was used for statistical analysis. RESULTS: The biofilm thickness reduced after treatment by both CTM and ZnO (P>0.05),while there was a significant decrease of the percentage of vital bacterias after treatment by CTM (P<0.01). CONCLUSIONS: The compound Chinese traditional medicine is effective on biofilm control, so that it would be an effective disinfecting drug for root canal sealers. Supported by Research Fund of Bureau of Traditional Chinese Medicine of Shanghai Municipality (Grant No.2008L008A).

Decreased expression of S100A6 in oral squamous cell carcinoma.

We previously established an in vitro cellular carcinogenesis model of oral squamous cell carcinoma (OSCC) with a line of human immortalized oral epithelia cells (HIOECs), a line of cancerous HB96 cells, and other cells (HB56 cells) at the early stage of carcinogenesis. In this study, comparative proteomic analysis identified a panel of differentially expressed proteins among these cells, and S100A6 was shown as one of the significantly down-regulated proteins accompanying cellular transformation. S100A6 was further validated for its expression in the three cell lines and in the clinical samples of cancerous and paracancerous tissues from 30 primary OSCC patients. Western blot analysis and real-time PCR revealed the decreased S100A6 protein and mRNA levels in the cancerous HB56 and HB96 cells over HIOECs. Immunohistochemistry and real-time PCR also showed decreased S100A6 protein and mRNA levels in the cancerous tissues compared to the paracancerous tissues from OSCC patients. The results presented here suggest that the expression of S100A6 decreases along with the cancerization in OSCC both in vitro and in vivo.

Downregulation of tapasin expression in primary human oral squamous cell carcinoma: association with clinical outcome.

MHC class I peptide loading complex defects are frequently observed in tumor cells which facilitate tumor cells escaping from immune surveillance. Tapasin plays an important role in the assembly of MHC class I molecules with peptides in the endoplasmic reticulum. The aim of this study was to investigate the expression of tapasin in primary oral squamous cell carcinoma (OSCC) and its potential clinical implication. Formalin-fixed, paraffin-embedded tumor biopsies from 67 patients with primary OSCC were analyzed for tapasin expression using immunohistochemistry. Tapasin promoter methylation status in OSCC cell lines was determined using ethylation-specific polymerase chain reaction, bisulphate genomic sequencing, and expression reactivation assay. Lack of tapasin expression was observed in 30 of 67 (43%) tumors and was significantly associated with poor pathologic differentiation grade of OSCC (P = 0.028). The cumulative 5-year survival rate was also significantly correlated with pathologic differentiation grade (P = 0.001) and tapasin expression level (P = 0.015). Decreased tapasin expression was an indicator of poor survival (P = 0.048). Tapasin promoter methylation was observed in all three OSCC cell lines examined, and the mRNA and protein levels of tapasin increased markedly after treatment with 5-aza-2'-deoxycytidine. Downregulation of tapasin is associated with a poor clinical outcome for OSCC patients and may serve as a prognostic biomarker. The promoter methylation may contribute to the tapasin downregulation in OSCC.

Overexpression of Galectin-1 is negatively correlated with pathologic differentiation grade in oral squamous cell carcinoma.

PURPOSE: To determine the Galectin-1 protein expression in oral squamous cell carcinoma (OSCC). METHODS: Comparative proteomic analysis of an in vitro cellular carcinogenesis model of OSCC we previously established was performed to identify differentially expressed proteins. Galectin-1 was further validated in vitro (human immortalized oral epithelia cell line and OSCC lines) and in vivo (tissue samples from OSCC patients) by Western blotting and immunohistochemistry, respectively. RESULTS: Increased Galectin-1 protein expression was identified in the cancerous cell line compared with the immortalized oral epithelial cell line in the in vitro cellular carcinogenesis model, and then validated in the OSCC lines and cancerous tissues. Galectin-1 protein expression was negatively correlated with the tumor pathologic differentiation grades, a higher Galectin-1 protein expression indicating a poorer pathologic differentiation grade. CONCLUSIONS: Galectin-1 protein expression level increases in OSCC, it may serve as a candidate marker for pathologic differentiation grade of OSCC.

Modeling of diffusion transport through oral biofilms with the inverse problem method.

AIM: The purpose of this study was to develop a mathematical model to quantitatively describe the passive transport of macromolecules within dental biofilms. METHODOLOGY: Fluorescently labeled dextrans with different molecular mass (3 kD, 10 kD, 40 kD, 70 kD, 2000 kD) were used as a series of diffusion probes. Streptococcus mutans, Streptococcus sanguinis, Actinomyces naeslundii and Fusobacterium nucleatum were used as inocula for biofilm formation. The diffusion processes of different probes through the in vitro biofilm were recorded with a confocal laser microscope. RESULTS: Mathematical function of biofilm penetration was constructed on the basis of the inverse problem method. Based on this function, not only the relationship between average concentration of steady-state and molecule weights can be analyzed, but also that between penetrative time and molecule weights. CONCLUSION: This can be used to predict the effective concentration and the penetrative time of anti-biofilm medicines that can diffuse through oral biofilm. Furthermore, an improved model for large molecule is proposed by considering the exchange time at the upper boundary of the dental biofilm.

Sonic hedgehog alleviates the inhibitory effects of high glucose on the osteoblastic differentiation of bone marrow stromal cells.

To assess the influence of high extracellular glucose levels on the osteogenic differentiation of bone marrow stromal cells (BMSCs) and to determine if Sonic hedgehog (Shh) protein can alleviate those effects. BMSCs were incubated with NG (normal glucose), NG+Shh (200 ng/ml Shh in normal glucose), NG+Shh+Gan (200 ng/ml Shh and 5 micromol/L GANT61 in normal glucose), HG (high glucose), HG+Shh (200 ng/ml Shh in high glucose), and HG+Shh+Gan (200 ng/ml Shh and 5 micromol/L GANT61 in high glucose). The expression levels of Shh signaling pathway genes Patched 1 (PTCH1) and osteogenesis-related genes were tested, which included bone morphogenetic protein 4 (BMP4), runt-related transcription factor 2 (Runx2), and osteopontin (OPN). Alkaline phosphatase (ALPase) activity and mineralized matrix formation were also investigated. Immunofluorescent staining of Gli1 was tested for Shh signaling activation. We found that recombinant Shh in normal-glucose medium could promote osteogenic differentiation of BMSCs, while inhibiting Shh signaling by GANT61 could antagonize this differentiation. Besides that high glucose impaired the Shh signaling as well as osteogenic differentiation of BMSCs, reactivation of Shh signal pathway by addition of Shh protein could mitigate the inhibition while further deactivation by Shh inhibitor GANT61 could retain their osteogenic inhibitions. The above data suggest that Shh pathway activity is involved in the HG condition mediated osteoblastic differentiation deficiency for BMSCs and that recombinant Shh could alleviate this inhibitory effect.

Comparative proteomic analysis of differentially expressed proteins in an in vitro cellular carcinogenesis model of oral squamous cell carcinoma.

In vitro cellular model is an important tool to be used to investigate the cellular events related to pathophysiological conditions in humans. We have developed an in vitro cellular carcinogenesis model of oral squamous cell carcinoma (OSCC). In this study, we performed comparative proteomic analysis using 2-DE and LC-tandem mass chromatography to separate and identify differentially expressed proteins. Forty-five proteins were identified, including 24 proteins with decreased expression and 19 proteins with increased expression during carcinogenesis from immortalized oral epithelial cells to squamous cancerous cells. The identified known proteins were classified into three ontologies of cellular component, molecular function, and biological process. Further validation of five identified proteins (ANXA1, ANXA2, CTSB, KRT17, and S100A6) in the cellular carcinogenesis model and cancerous tissues from OSCC patients confirmed the comparative proteomic results. Moreover, Annexin A1 and A2 expression levels correlated with the pathological differentiation grade of cancerous tissues. Thus, this work provides a dynamic protein file of differentially expressed proteins in oral squamous carcinoma cells, which could provide clues to study the mechanisms of OSCC carcinogenesis and possibly be developed as potential biomarkers for clinical diagnosis or prognostic monitoring.

Characteristics of a cancerous cell line, HIOEC-B(a)P-96, induced by benzo(a)pyrene from human immortalized oral epithelial cell line.

Oral squamous cell carcinoma (OSCC) is the most common malignant tumor in the oral and maxillofacial region. The mechanism of carcinogenesis of OSCC is still unclear. In vitro study on OSCC cell lines, especially derived from immortalized oral epithelial cells, is a very useful strategy to understand the mechanism of carcinogenesis. Based on our previous human immortalized oral epithelial cell (HIOEC) line, obtained from normal oral epithelial cells by transfection of HPV16 E6/E7 gene, a new cancerous cell line, HIOEC-B(a)P-96 (HB96), was established from the HIOEC by induction with benzo(a)pyrene. The characteristics of the HB96 cells such as cell morphology, ultrastructure, proliferation ability, invasion ability, and tumorigenesis were studied. The HB96 cells lost contact inhibition with uncontrolled cell division and obvious cell overlap, they were polygonal in shape and ununiform in size with increased ratio between nucleus and plasma. Increased proliferative ability and invasion ability were confirmed by the cell proliferation analysis and cell invasion assay, respectively. The tumorigenicity of well to moderately differentiated squamous cell carcinoma was confirmed in the nude mice experiments pathologically. Increased expression of HPV16 E6/E7 proteins and obvious correlation with decreased expression of p53 and Rb proteins was also confirmed by Western blotting. Thus, this HB96 cell line induced by benzo(a)pyrene from the HIOEC line is a useful tool to study the mechanism of carcinogenesis of OSCC in vitro for future genomic and proteomic analyses. It is also the first in vitro cancerous cell line of OSCC in China derived from immortalized oral epithelial cells.

[Establishment and identification of biological characteristics of rat monoclone cell line Rca-B].

OBJECTIVE: To establish a monoclone cell line of squamous cell carcinoma (SCC) in rat buccal mucosa and to study its biological characteristics. METHODS: SCC in rat oral mucosa was induced by adding 4-nitroquinoline-1-oxide (4NQO) into the SD rats' drinking water, and the cancer cells were then cultured to obtain mixed cells in vitro. The mixed tumor cells were purified by mono cell cloning method. The biological characteristics of the cells were studied by microscope and electronic microscope observation, chromosome analysis, Methyl thiazolyl tetrazolium (MTT) test, flow cytometry assay and immunohistochemistry staining. Hypodermic inoculations of the cells in nude mice and injection of the cells by nude mice tail veins were performed to observe the tumor formation and long distance metastasis. RESULTS: The morphology proved that the cell line was squamous cell carcinoma cells, which were cultured from one cell. The population doubling time for passage 65 cells was 25.44 hours. The cells in S-phase accounted for 20.13% of the cell cycle. The chromosome modal number was 84. All the cells expressed the proteins of cytokeratin and vimentin. The xenograft rate and the tumor metastatic rate to the lung were 100% in nu/nu BALB/C mice, but the homograft rate was zero in SD Rats. CONCLUSIONS: Rca-B was a typical oral squamous cell carcinoma cell line derived from Sprague-Dawley rat buccal mucosa carcinoma, and the cell line has high metastatic potential and its biological characteristics were well ascertained.

[Synthesized small interfering RNA inhibits the expression of DNA methyltransferase 1 in salivary adenoid cystic carcinoma].

OBJECTIVE: To select the effective siRNA which could inhibit the expression of DNA methyltransferase 1 (DNMT-1) in adenoid cystic carcinoma (ACC) and discuss the time-, and dose-dependent effect of RNA interference (RNAi). METHODS: Four pairs of siRNA were designed, synthesized and transfected through oligofectamine reagent into ACC cell lines ACC-2, ACC-3 and ACC-M. 24, 48 and 72 h after transfection, total RNA and protein were harvested respectively. mRNA and protein expression level of DNMT-1 were detected by real time PCR, RT-PCR and Western blot, and then the effective siRNA was subsequently selected. ACC-3 as also transfected by different concentration of siRNA and the dose-dependent effect of RNAi was discussed. Cy(3) labelled GAPDH siRNA was used as a positive control. RESULTS: Two of 4 pairs of siRNA inhibited the mRNA expression of DNMT-1 in three ACC cell lines and the expression of DNMT-1 was downregulated by 67%, 86%, 92% and 76%, 76%, 86% respectively. The gene inhibition was detected at 24 h or 48 h after transfection, maintained only 1 - 2 days and showed direct relationship to the concentration of siRNA. The change of protein expression level of DNMT-1 was consistent to the changes of mRNA. CONCLUSIONS: The effective siRNA which could inhibited the expression of DNMT-1 of ACC were achieved. The inhibition effect of RNAi was time-dependent and dose-dependent.

[Experimental study on ultrasound heating affecting the sensitivity of oral carcinoma to chemotherapy drugs].

OBJECTIVE: To explore the influence of chemosensitivity of Tca8113 cells by modified MTT assay after the animal model of Tca8113 were treated by the ultrasound hyperthermia. METHODS: The MTT assay of the BALB/C nu/nu mice model of Tca8113 cells treated by the ultrasound hyperthermia in vivo was performed. RESULTS: The chemosensitivity to the 9 kinds of drugs demonstrated no significant differences between the Tca8113 cells in the control group, the 39 degrees C-treated group and the groups treated from 41 degrees C to 44 degrees C. But significant differences between the 40 degrees C-treated group and the 41 degrees C or 42 degrees C-treated group existed. In the heating-time grades test, there were no significant differences in the chemosensitivity to the 9 kinds of drugs between these three pairs of group (the control group and the 15 min-treated group, the 30 min-treated and the 45 min-treated group, the 60 min-treated and the 75 min-treated group). But there were significant differences between the 30 min-treated or the 45 min-treated group and the 60 min-treated or the 75 min-treated group. CONCLUSION: Ultrasound hyperthermia performed in 42 degrees C for 30-45 min can improve the chemosensitivity of Tca8113 cells to some drugs significantly, which confirms the rationality of synchronous combination of hyperthermia and chemotherapy in the chemosensitivity point of view for the first time.