No abstract available.
Humans ; KB Cells* ; NADP* ; NADPH Oxidase ; Oxidoreductases* ; Porphyromonas gingivalis* ; Porphyromonas*

OBJECTIVETo investigate the induction of apoptosis on human oral epidermoid carcinoma KB cells and multidrug resistant KBv200 cells by Matrine.

METHODSMTT assay was used to investigate the inhibition ability of Matrine on the cells in vitro. Transmission electron microscope was used to observe the ultrastructure feature of cells. after treated by Matrine. Acridine orange (AO)/Ethidium bromide (EB) fluorescent staining and flow cytometry were used to observe apoptosis induced by Matrine. Flow cytometry was applied to study the effects of the drug on cell cycles of the cells.

RESULTSWhen 0.50, 1.00, 1.50, 2.00 mg/ml of Matrine was used, the vital rates of KB and KBv200 cells were decreased according to Matrine's concentration. The IC50 concentrations of Matrine on KB and KBv200 cells were 1.35 mg/ml and 1.43 mg/ml individually. The results of AO/EB fluorescent staining and flow cytometry showed that Matrine could induce apoptosis of two kinds of cells. While observed by transmission electron microscope, there were more contraction of cells, condensation of nuclei, bubble of cytoplasm in both kinds of cells after treated by Matrine. Matrine could stop the growth of KB and KBv200 cells at S period and restrain mitosis of cells.

CONCLUSIONMatrine can inhibit the growth of KB and KBv200 cells by inducing apoptosis. The apoptosis effect is dose-dependent and it has certain relation to the blocking of S period cells.

We evaluated the ability of lactic acid bacteria, Weissella cibaria, isolated from the oral cavity to adhere to epithelial cells. W. cibaria efficiently adhered to KB cells and HeLa cells. In addition, W. cibaria efficiently adhered to Fusobacterium nucleatum. But the adhesiveness of W. cibaria disappeared upon exposure to LiCl or pronase, suggesting that the S-layer proteins of W. cibaria mediated the adhesiveness. The molecular mass of the S-layer proteins extracted from W. cibaria was approximately 50 kDa. When W. cibaria strains were washed with 0.45% saline, the bacteria were efficiently adhered to the epithelial cells. In conclusion, W. cibaria has the ability to adhere to epithelial cells through the S-layer proteins.
Adhesiveness ; Bacteria ; Epithelial Cells* ; Fusobacterium nucleatum ; HeLa Cells ; Humans ; KB Cells ; Lactic Acid ; Mouth ; Pronase ; Weissella*

The radiation-induced apoptosis was studied for two human cancer cell lines (KB cells, RPMI 2650 cells) and the human gingival fibroblast cell line (HGF-1 cells). The single irradiation of 2, 10, 20Gy was done with 241.5 cGy/min dose rate using the 137Cs MK cell irradiator. The cell were stained with propidium iodide and examined under the fluoro-microscope and assayed with the flow cytometry a day after irradiation. Also, the LDH assay was done to determine the amount of necrotic cells. The obtained results were as follows : 1. On the fluoro-microscope, many fragmented nuclei were detected in the KB, RPMI 2650, and HGF-1 cells after irradiation. 2. On the DNA content histogram obtained from the flow cytometry, the percentages of the pre-G1 peak of the control and 2, 10 and 20Gy irradiation group were 4.5, 55.0, 52.3, and 66.6% on KB cells, 2.7, 3.3, 31.8, and 32.6% on RPMI 2650 cells and 2.8, 21.8, 30.4, and 40.2% on HGF-1 cells respectively. 3. The number of G1-stage cells was abruptly decreased after 2Gy irradiation on KB cells and 10Gy irradiation on RPMI 2650 cells, But there was a slight decrease without regard to irradiation dose on HGF-1 cells. 4. There was no significantly different absorbance in extracellular LDH assay along the experimental cell lines.
Apoptosis* ; Cell Line* ; DNA ; Fibroblasts* ; Flow Cytometry ; Humans* ; KB Cells ; Propidium

The purpose of this study was to aid in the prediction of tumor cell tolerance to radiotherapy and/or chemotherapy. For this study, cell surviving curves were obtained for human squamous cell carcinoma KB cell line after radiation exposure and/or administration of antitumor drugs. 2, 4, 6, 8 10Gy were irradiated at a dose rate of 210Gy/min using 60Co Irradiator ALDORADO 8. After irradiation, KB cell lines(3*104cells/ml) were exposed to 2 /ml of bleomycin ir cisplatin for 1 hour. The viable cells were determined by MTT assay for each radiation dose and/or each drug at the 4th day. And they were compared to control values. The obtained results were as follows ; 1. The slope of the surviving curve after irradiation of 2, 4, 6, 8, 10Gy on KB cell line was relatively steep. 2. There was no significant difference between ths cytotoxicity of bleomycin compared to control group. But, there was significant difference between the cytotoxicity of cisplatin compared to control group. And the cytotoxicity of cisplatin was greater than that of bleomycin on KB cell line. 3. There were dignificant differences of surviving fractions after irradiation of 2Gy and 10Gy with 2 /ml of bleomycin compared with the groups of irradiation only on KB cell line. 4. There were significant differences of surviving fractions after irradiation of 2, 4, 6, 8, 10Gy with 2 /ml of cisplantin compared with the groups of irradiation only on KB cell line. 5, There was significant difference of surviving fraction between groups after irradiation of 10Gy with 2 /ml of bleomycin and cisplatin.
Antineoplastic Agents ; Bleomycin ; Carcinoma, Squamous Cell ; Cisplatin ; Drug Therapy ; Humans ; KB Cells* ; Radiation Tolerance* ; Radiotherapy

PURPOSE: The study was aimed to detect the differences in the cell viability and the apoptosis induction after irradiation on normal and tumorigenic cells. MATERIALS AND METHODS: The study, that was generated for two human normal cells(RHEK, HGF-1) and two human tumor cells(KB, HT-1080), was tested using MTT assay at 1 day and 3 day after irradiation and TUNEL assay under confocal laser scanning microscope at 1 day after irradiation. Single irradiation of 0.5, 1, 2, 4, and 8 Gy were applied to the cells. The two fractions of 1, 2, 4, and 8 Gy were separated with a 4 hour time interval. The irradiation was done with 5.38 Gy/min dose rate using Cs-137 irradiator at room temperature. RESULTS AND CONCLUSIONS: 1. In 3-day group, the cell viability of HGF-1 cell was significantly decreased at 2, 4 and 8 Gy irradiation, the cell viability of KB cell was significantly decreased at 8 Gy irradiation and the cell viability of HT-1080 cell was significantly decreased at 4 and 8 Gy irradiation. 2. There was significant difference between RHEK and KB cell line in the cell viability of 3-day group at 8 Gy irradiation. There was significant difference between RHEK and HGF-1 cell line in the cell viability of 3-day group at 4 and 8 Gy irradiation. 3. There was a significantly decreased cell viability in 3-day group than those in 1-day group at 2, 4 and 8 Gy on HGF-1 cell, at 4 and 8 Gy on HT-1080 cell, at 8 Gy on KB cell. 4. We could detect DNA fragmented cells only on KB cell. Number of apoptotic cells of KB cell was significantly increased at 4 and 8 Gy irradiation. However, there was no correlation between cell viability and apoptosis. 5. On all 4 cell lines, there were no differences between single and split irradiation method in cell viability and apoptosis.
Apoptosis* ; Cell Line ; Cell Survival* ; DNA ; Humans ; In Situ Nick-End Labeling ; KB Cells ; Radiation Dosage*

Cyclooxygenase-2 (Cox-2) is known as one of the critical factor in carcinomas of various organs. However, the importance of Cox-2 in oral squamous cell carcinoma has not been fully described yet. The purpose of this study is to evaluate the anti-cancer effect of selective cox-2 inhibitor, celecoxib in an oral squamous cell carcinoma cell line, KB with respect to cytotoxicity test, in vitro invasion and MMP-2 expression. In cytotoxicity test, celecoxib treated group showed definitely concentration dependent cytotoxicity. In addition, administration of celecoxib reduced the invasive potential of KB cell line significantly in invasion assay. However, there was no remarkable difference of the MMP-2 expression between the celecoxib treated group and the control group. Considering these data, celecoxib had a potential cytotoxic agent to oral squamous cell carcinoma cells. Also, it had anti-invasive property without acting on the MMP-2 expression mechanism. Therefore, it was postulated that celecoxib had the possibility of anti-cancer agent in treatment strategies of oral squamous cell carcinoma.
Carcinoma, Squamous Cell* ; Cell Line* ; Cyclooxygenase 2 ; Humans ; Celecoxib ; KB Cells

Ursolic acid is a triterpenoid compound present in many plants. This study examined the antimicrobial activity of ursolic acid against mutans streptococci (MS) isolated from the Korean population. The antimicrobial activity was evaluated by the minimum inhibitory concentration (MIC) and time kill curves of MS. The cytotoxicity of ursolic acid against KB cells was tested using an MTT assay. The MIC90 values of ursolic acid for Streptococcus mutans and Streptococcus sobrinus isolated from the Korean population were 2 microg/ml and 4 microg/ml, respectively. Ursolic acid had a bactericidal effect on S. mutans ATCC 25175T and S. sobrinus ATCC 33478T at > 2 x MIC (4 microg/ml) and 4 x MIC (8 microg/ml), respectively. Ursolic acid had no cytotoxic effect on KB cells at concentrations at which it exerted antimicrobial effects. The results suggest that ursolic acid can be used in the development of oral hygiene products for the prevention of dental caries.
Dental Caries ; Humans ; KB Cells ; Microbial Sensitivity Tests ; Oral Hygiene ; Streptococcus mutans ; Streptococcus sobrinus ; Triterpenes

To investigate the effect of chrysin on apoptosis of oral squamous carcinoma KB cell line and the possible mechanisms, and to provide new ideas for the treatment of oral cancer.
 Methods: Oral cancer KB cells were treated with different concentrations of chrysin (1, 2, 4, 8, 16, and 32 μmol/L) for 24 h. Cell proliferation was detected by MMT assay; apoptosis was detected by flow cytometry; the activity of caspase-3/7 was detected by chemiluminescent assay; mitochondrial membrane potential in KB cells was determined by JC-1 assay; and Western blotting was used to determine the activation of protein kinase B (AKT) and phosphoinositide-3-kinase (PI3K).
 Results: Chrysin inhibited the proliferation of KB cells in a concentration-dependent manner, accompanied by increase in apoptosis of KB cells, activation of caspase-3/7, decrease in mitochondrial membrane potential, and suppression of the phosphorylation of AKT and PI3K.
 Conclusion: The effect of chrysin on KB cell apoptosis may be related to mitochondrial dysfunction and inhibition of PI3K/AKT pathway.
Apoptosis ; Carcinoma, Squamous Cell ; Flavonoids ; Humans ; KB Cells ; Mouth Neoplasms ; Phosphatidylinositol 3-Kinases ; Signal Transduction

PURPOSE: Ionizing radiations have been reported as an apoptosis initiating stimulus in various cells and it has established that sustained elevations in [Ca2+] can lead to DNA fragmentation by Ca2+-dependent endonucleases, ultimately resulting in apoptotic cell death. The previous experiments have been reported by using primarily thymocytes and lymphocytes and the change of [Ca2+] was measured only by minutes or hours respectively. We need to evaluate [Ca2+] in both several minutes and hours after irradiation of radiation of radiation therapy and verify the apoptotic cells. MATERIALS AND METHODS: We have measured [Ca2+] in human gingival epitheloid cancer cell with 10 Gy irradiation, at minutely intervals and hourly intervals using digitized video-intensified fluorescence microscopy and the fluorescent Ca2+ indicator dye, fura-2. In order to find out that the transient rise in [Ca2+] could induced apoptosis, cells were incubated for 1 hour at 37 degrees C with TdT enzyme, rinsed and resuspended containing fluorescence and observed under a confocal fluorescence microscope. MTT assay was done to determine cell activity and LDH assay was done to determine the amount of necrotic cells. RESULTS: After irradiation, the transient and temporal increasing of [Ca2+] in the KB cells was founded. Though, there was no change in the intracellular [Ca2+] at 30 minutes and 2 hours after irradiation. We could detect of DNA fragmented cells at 4 hours after 10 Gy irradiated cells. There were no significant differences between 4 hour, 1 day, 3 day cells. There were no significant differences in MTT and LDH assay between the irradiated group and the control group after 4 hours and 1 day. Though after 3 days there were differences in MTT and LDH assay between the irradiated group was significantly decreased than the control group, in LDH assay the number of necrotic cell death of the irradiated was higher than the control group. CONCLUSION: In KB cells there were incipient and temporal increasing of the [Ca2+] with 10 Gy irradiation and the apoptosis was founded from 4 hours later which was earlier than seeing of the change of the amount of the cellular ability and necrosis.
Apoptosis* ; Cell Death ; DNA ; DNA Fragmentation ; Endonucleases ; Fluorescence ; Fura-2 ; Humans ; KB Cells* ; Lymphocytes ; Microscopy, Fluorescence ; Necrosis ; Radiation, Ionizing ; Thymocytes