Biomedical subjects

Wantao Chen

Publications and source records attributed to Wantao Chen.

8 recordsLinked to original sources

PubMed2006

Identification of genes associated with cisplatin resistance in human oral squamous cell carcinoma cell line.

BACKGROUND: Cisplatin is widely used for chemotherapy of head and neck squamous cell carcinoma. However, details of the molecular mechanism responsible for cisplatin resistance are still unclear. The aim of this study was to identify the expression of genes related to cisplatin resistance in oral squamous cell carcinoma cells. METHODS: A cisplatin-resistant cell line, Tca/cisplatin, was established from a cisplatin-sensitive cell line, Tca8113, which was derived from moderately-differentiated tongue squamous cell carcinoma. Global gene expression in this resistant cell line and its sensitive parent cell line was analyzed using Affymetrix HG-U95Av2 microarrays. Candidate genes involved in DNA repair, the MAP pathway and cell cycle regulation were chosen to validate the microarray analysis results. Cell cycle distribution and apoptosis following cisplatin exposure were also investigated. RESULTS: Cisplatin resistance in Tca/cisplatin cells was stable for two years in cisplatin-free culture medium. The IC50 for cisplatin in Tca/cisplatin was 6.5-fold higher than that in Tca8113. Microarray analysis identified 38 genes that were up-regulated and 25 that were down-regulated in this cell line. Some were novel candidates, while others are involved in well-characterized mechanisms that could be relevant to cisplatin resistance, such as RECQL for DNA repair and MAP2K6 in the MAP pathway; all the genes were further validated by Real-time PCR. The cell cycle-regulated genes CCND1 and CCND3 were involved in cisplatin resistance; 24-hour exposure to 10 microM cisplatin induced a marked S phase block in Tca/cisplatin cells but not in Tca8113 cells. CONCLUSION: The Tca8113 cell line and its stable drug-resistant variant Tca/cisplatin provided a useful model for identifying candidate genes responsible for the mechanism of cisplatin resistance in oral squamous cell carcinoma. Our data provide a useful basis for screening candidate targets for early diagnosis and further intervention in cisplatin resistance.

Carcinoma, Squamous Cell↗

PubMed2006

Topoisomerase II trapping agent teniposide induces apoptosis and G2/M or S phase arrest of oral squamous cell carcinoma.

BACKGROUND: Teniposide (VM-26) has been widely used in the treatment of small cell lung cancer, malignant lymphoma, breast cancer, etc. However, there are few reports on VM-26 against oral cancers. The present study was designed to identify the effect of VM-26 against oral squamous cell carcinoma in vitro, and to provide evidence for the feasibility and effectiveness of VM-26 for application to the patients with oral cancer. METHODS: Human tongue squamous cell carcinoma cell line, Tca8113, was used. Cells were incubated with different concentrations of VM-26 for a variety of time span. Cisplatin (CDDP) was employed as a control reagent. MTT assay was used to assess the inhibitory rate of Tca8113 growth. Flow cytometer (FCM), transmission electronic microscope (TEM) and fluorescence staining were employed for determining the cell apoptotic rate. Cell cycle distribution of Tca8113 incubated with VM-26 was examined by flow cytometer assay. Statistic software (SAS 6.12, USA) was used for one-way ANOVA. RESULTS: The IC50 of VM-26 against Tca8113 cells was 0.35 mg/l and that of CDDP was 1.1 mg/l. The morphological changes of Tca8113 cells were observed with fluorescence microscope and TEM. Apoptotic morphological feature could be found in the nucleus. Apoptotic rate of Tca8113 cells incubated with 5.0 mg/l of VM-26 for 72 hours was 81.67% and cells were arrested at S phase. However, when exposed to 0.15 mg/l of VM-26 for 72 hours, G2/M phase increased from 12.75% to 98.71%, while the apoptotic rate was 17.38%, which was lower than that exposed to 5.0 mg/l of VM-26. CONCLUSION: VM-26 could significantly induce apoptosis of oral squamous cell carcinoma and inhibit cell growth. There may be another pathway to induce apoptosis of oral squamous cell carcinoma cells except for G2/M phase arrest.

Journal Article↗

PubMed2003

Different cDNA microarray patterns of gene expression reflecting changes during metastatic progression in adenoid cystic carcinoma.

BACKGROUND: The metastatic ability of tumor cells is determined by level of expression of specific genes that may be identified with the aid of cDNA microarray containing thousands of genes and can be used to establish the expression profile of disease related genes in complex biological system. MATERIALS AND METHODS: Salivary adenoid cystic carcinoma cell line and its high metastases adenoid cystic carcinoma clone were used as model systems to reveal the gene expression alteration related to metastasis mechanism by cDNA microarray analysis. The correlation of metastatic phenotypic changes and expression levels of 4 selected genes (encoding CD98, L6, RPL29, and TSH) were further validated by using RT-PCR analysis of human tumor specimens from primary adenoid cystic carcinoma and corresponding metastasis lymph nodes. RESULTS: Of the 7,675 clones of known genes and expressed sequence tags (ESTs) that were analyzed, 30 showed significantly different (minimum 3 fold) expression levels in two cell lines. Out of 30 genes found differentially expressed, 18 were up regulated (with ratio more than 3) and 12 down regulated (with ratio less than 1/3). CONCLUSION: 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.

Journal Article↗

PubMed2003

Identification of genes with consistent expression alteration pattern in ACC-2 and ACC-M cells by cDNA array.

OBJECTIVE: To investigate the molecular events and metastasis-related genes in ACC-2 and ACC-M cells of adenoid cystic carcinoma. METHODS: Adenoid cystic carcinoma cell line ACC-2 and a sample of adenoic cystic carcinoma cell clones highly metastatic to the lung (ACC-M) were investigated. ACC-2 and ACC-M cells were cultured and collected. Total RNA was extracted using standard Trizol RNA isolation protocol. The poly A mRNA was purified and labeled in reverse transcription using M-MLV reverse transcriptase in the presence of Easytides deoxyadenosin 5' triphosphate [alpha-(33)p]. A cDNA array was assembled with 7675 EST clones which represented the same number of independent single genes. Prepared nylon membranes were hybridized with the [alpha (33)p]-dATP labeled mRNA from ACC-2 and ACC-M cells. Membranes were exposed to phosphor screen. RESULTS: The high-through put analysis of gene expression pattern was obtained from ACC-2 and ACC-M cells by the hybridization of the cDNA array. The difference of parallel gene expression was analyzed. Genes were clustered according to their expression level in the ACC-M compared with ACC-2 cells. According to each gene's ratio of expression level, there were 17 genes which were upregulated with ratios over 3.0, and there were 12 genes which were downregulated with ratios below 0.33 (1/3.0 = 0.33). CONCLUSIONS: Significantly different expression patterns between ACC-2 and ACC-M by cDNA array were observed. The differences lie in signal pathways, tumor antigens, immune molecular and some unknown genes.

Adult↗

PubMed2002

[Establishment of human immortalized oral epithelial cell line HIO615 induced by HPV16 E6 and E7].

OBJECTIVE: To establish an immortalized oral epithelial cell line. METHODS: Normal human oral epithelial cells were transfected with HPV16E6/E7 open reading frames using recombinant retroviral system pLXSN. Expression of HPV16E6 and E7 protein were tested by Western blot in three kinds of cells. To define cellular biological characterization of HPV16E6/E7 transfected cells, a series analysis were performed, including protraction of growth curve, HE staining, immunocytochemical staining and scanning electron microscope observation. The tumorigenicity was assessed by colony formation and transplanting the cells into nude mice. RESULTS: Human oral epithelial cells transfected with HPVE6/E7 has been in culture for over 18 months. The cell line was named HIO615. Western blot analysis showed HIO615 expressed HPV16 E6 and E7 protein. HIOC were positive for cytokeratin, tonofibril and desmosome as observed by scanning electron microscope. The number of large colonies of dense multilayer cells was low (0.77%). No tumor developed in nude mice injected subcutaneously with HIOEC. CONCLUSION: A human immortalized oral epithelial cell line induced by HPV16E6 and E7 has been successfully established.

Animals↗

PubMed2002

[Relation between the expression of P-gp and GST-pi in oral and maxillofacial squamous carcinoma and chemoresistance].

OBJECTIVE: To investigating the relation between the expression of P-glycoprotein and Glutathione transferase-pi and the chemoresistance. METHODS: The expressions of these two proteins in patients with oral and maxillofacial squamous carcinoma and normal oral tissues were detected by immunohistochemistry. RESULTS: The positive expression rate of P-gp and GST-pi in oral and maxillofacial malignant tumor was 57.1% and 53.6% respectively, and no expression in normal oral tissues; the expression of GST-pi was relevant to the resistance to cisplatin, while the expression of P-gp was relevant to the resistance to chemotherapeutic drug in general. CONCLUSIONS: The method of immunohistochemistry combining MTT assay in vitro may become an efficient way to predict the sensitivity to chemotherapeutic drug.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2002

[Paclitaxel-induced apoptosis in ACC-2 cells is associated with the arrest of G(2)/M].

OBJECTIVE: To investigate whether paclitaxel (Taxel) can efficiently induce apoptosis of ACC-2 or not, and to study the relation of apoptosis and arrest of cell mitosis. METHODS: Paclitaxel-induced arrest of cell mitosis and apoptosis of ACC-2 cells in various concentration and different treat time were determined using transmission electron microscope (TEM), fluorescence microscope, flow-cytometry and DNA agarose gel electrophoresis technique. RESULTS: Under fluorescence microscope, apoptotic cells were green with irregular clumping of nucleus chromatin, or even nuclear chromatin segregation. The typical ultra-structural changes of apoptosis observed by TEM were cell compaction, margination of nuclear chromatin, condensation of cytoplasm, protuberances and apoptotic body. "DNA Ladder" was absent in agarose gel electrophoresis of DNA extracted from culture of ACC-2 cells and paclitaxel-induced ACC-2 cells. "Sub-G(1)" phase peak of ACC-2 cells induced by 50 nmol/L paclitaxel in 48 h and 72 h was 17.13% and 16.26%, respectively. The percentage of G(2)/M phase increased in accordance with raise of the paclitaxel concentration and prolongation of treatment. The typical ultra-structural changes of apoptosis were observed in case that G(2)/M phase was arrested. CONCLUSIONS: Paclitaxel could induce apoptosis of ACC-2 cells. Arrest of G(2)/M phase might induce apoptosis of ACC-2 cells.

Apoptosis↗

PubMed2002

[Chemosensitivity testing of oral and maxillofacial cancer with biopsy specimens].

OBJECTIVE: To determine the chemosensitivity in fresh biopsy specimen of human oral and maxillofacial cancer, and the differential chemosensitivity among those drugs used popularly in clinic. METHODS: Human biopsy cancer cells were obtained from 150 oral and maxillofacial malignant tumors. The antitumor drugs tested using modified MTT assay were cisplatin (CDDP), 5-fluorouracil (5-Fu), Pinyangmycin (PYM), Paclitaxel (Taxol), Teniposide (Vm-26), Epi-adriamycin (E-ADM), Vindesin (VDS) and Methortrexatum (MTX). RESULTS: The success rate of the MTT assay was 93.33% (140 of the 150 cases). At a drug concentration of Cmax x 5, the inhibition rates of oral tumor cells were 63.76% for Vm-26, 25.93% for CDDP, 25.86% for E-ADM, 23.52% for Taxol, 22.97% for PYM, 22.08% for 5-Fu, 18.42% for VDS and 18.93% for MTX. The inhibition rate of VM26 was significantly higher than any of other seven chemotherapeutic drugs (P < 0.05). Over forty percent patients with squamous cell carcinoma showed moderate chemosensitivity to VM-26, CDDP and E-ADM, and over forty percent cases with adenoid carcinoma showed moderate chemosensitivity to Vm-26, Taxol and E-ADM. CONCLUSIONS: Most oral and maxillofacial cancers showed chemosensitivity to Vm-26, CDDP, E-ADM and Taxol. Vm-26, E-ADM and Taxol were more potent drugs than VDS, 5-Fu and MTX against oral and maxillofacial cancer cells. Chemosensitivity testing using modified MTT assay was useful in selecting antitumor drugs for patients with oral and maxillofacial cancers.

Antineoplastic Agents↗