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

β-carotene is present in carrots, pumpkins, and sweet potatoes. It suppresses many types of cancers by regulating cellular proliferation and apoptosis through a variety of mechanisms. However, the effects of β -carotene on oral cancer cells have not been clearly established. The main goal of this study was to investigate the effects of β-carotene on cell growth and apoptosis in oral cancer cells. Our results demonstrate that treatment with β-carotene induced inhibition of cell growth, and that the effect was dependent on β-carotene treatment time and concentration in KB cells. Furthermore, treatment with β-carotene induced nuclear condensation and fragmentation in KB cells. β-carotene promoted proteolytic cleavage of procaspase-3, -7, -8 and -9 with associated increases in the concentration of cleaved caspase-3, -7, -8 and -9. In addition, the level of cleaved PARP was increased by β-carotene treatment in KB cells. These results suggest that β-carotene can suppress cell growth and induce apoptosis in KB human oral cancer cells, and that it may have potential usefulness in anti-cancer drug discovery efforts.
Apoptosis ; Caspase 3 ; Cell Death ; Cell Proliferation ; Cucurbita ; Daucus carota ; Drug Discovery ; Humans* ; Ipomoea batatas ; KB Cells ; Mouth Neoplasms*

Tyrosol, a phenylethanoid and a derivative of phenethyl alcohol, possesses various biological properties, such as anti-oxidative and cardioprotective activity. Olive oil is the principal source of tyrosol in the human diet. However, so far the anti-cancer activity of tyrosol has not yet been well defined. This study therefore undertakes to examine the cytotoxic activity and the mechanism of cell death exhibited by tyrosol in KB human oral cancer cells. Treatment of KB cells with tyrosol induced the cell growth inhibition in a concentration- and a time-dependent manner. Furthermore, the treatment of tyrosol induced nuclear condensation and fragmentation of KB cells. Tyrosol also promoted proteolytic cleavage of procaspase-3, -7, -8 and -9, increasing the amounts of cleaved caspase-3, -7, -8 and -9. In addition, tyrosol increased the levels of cleaved PARP in KB cells. These results suggest that tyrosol induces the suppression of cell growth and cell apoptosis in KB human oral cancer cells, and is therefore a potential candidate for anti-cancer drug discovery.
Apoptosis ; Caspase 3 ; Cell Death ; Diet ; Drug Discovery ; Humans* ; KB Cells ; Mouth Neoplasms* ; Olive Oil ; Phenylethyl Alcohol

The purpose of the study was to investigate the antimicrobial activity of the methanol extract of Coptidis rhizome against the type strains of cariogenic bacteria, Streptococcus mutans and Streptococcus sobrinus, and the periodontopathogens, Porphyromonas gingivalis, Prevotella intermedia, Treponema denticola and Aggregatibacter actinomycetemcomitans. The antimicrobial activities of the crude extract and the methanol extract fractions of Coptidis rhizome separated by silica gel chromatography were evaluated by determining the minimal bactericidal concentration (MBC) values, using the microdilution method. The cell viability test of the extracts of Coptidis rhizome on the KB cells was also studied by methyl thiazolyl tetrazolium (MTT) assay. Our results showed that the 11th fraction (F11) of the methanol extract had the greatest antimicrobial activity against the tested bacteria, with no associated cytotoxicity on the KB cells, upto a concentration of 50 microg/ml. These results suggest that the silica gel chromatography fraction F11 of the methanol extract of Coptidis rhizome, could be useful in the development of oral hygiene products as an antimicrobial agent for the prevention of dental caries and periodontal diseases.
Aggregatibacter actinomycetemcomitans ; Bacteria ; Cell Survival ; Chromatography ; Dental Caries ; Humans ; KB Cells ; Methanol ; Oral Hygiene ; Periodontal Diseases ; Porphyromonas gingivalis ; Prevotella intermedia ; Rhizome* ; Silica Gel ; Streptococcus mutans ; Streptococcus sobrinus ; Treponema denticola

The present study was designed to target fish for potential bioactive components contained in a Huang Lian Jie Du decoction (HLJDD) and identify the underlying mechanisms of action for the treatment of sepsis at the molecular level. he bioactive components database of HLJDD was constructed and the sepsis-associated targets were comprehensively investigated. The 3D structures of the PAFR and TXA2R proteins were established using the homology modelling (HM) method, and the molecular effects for sepsis treatment were analysed by comparing the bioactive components database and the sepsis targets using computational biology methods. The results of the screening were validated with biological testing against the human oral epidermal carcinoma cell line KB in vitro. We found that multiple bioactive compounds contained in the HLJDD interacted with multiple targets. We also predicted the promising compound leads for sepsis treatment, and the first 28 compounds were characterized. Several compounds, such as berberine, berberrubine and epiberberine, dose-dependently inhibited PGE2 production in human KB cells, and the effects were similar in the presence or absence of TPA. This study demonstrates a novel approach to identifying natural chemical compounds as new leads for the treatment of sepsis.
Anti-Inflammatory Agents, Non-Steroidal ; pharmacokinetics ; Berberine ; analogs & derivatives ; pharmacokinetics ; Dinoprostone ; biosynthesis ; Drugs, Chinese Herbal ; chemistry ; pharmacokinetics ; Humans ; KB Cells ; Platelet Membrane Glycoproteins ; drug effects ; Protein Transport ; Receptors, G-Protein-Coupled ; drug effects ; Receptors, Thromboxane A2, Prostaglandin H2 ; drug effects ; Sepsis ; drug therapy ; metabolism ; Tetradecanoylphorbol Acetate ; pharmacokinetics

OBJECTIVETo investigate the effects of metformin on the proliferation and apoptosis of human oral cancer cell line KB in vitro.

METHODSHuman oral cancer cell line KB was exposed to different doses of metformin (0, 1.25, 2.5, 5, 10, and 20 mmol/L), and the changes in cell viability were detected using MTT assay. Colony formation of the cells was observed following an 8-day metformin exposure. The changes in mitochondrial membrane potential were measured by JC-1 assay, and PI staining was used to observe the cell apoptosis. Western blotting was employed to detect the changes in the protein expressions of GRP78 and activated caspase-3.

RESULTSMetformin exposure caused time- and dose-dependent suppression of KB cell proliferation, and exposure to 5 mmol/L metformin for 24, 48 and 72 h resulted in cell survival rates of 68.0%, 36.9%, and 14.5%, respectively. Metformin significantly inhibited KB cell colony formation. Exposure of the cells to increased concentrations of metformin gradually increased the apoptotic rate and decreased mitochondrial membrane potential. Metformin caused an initial up-regulation followed by a down-regulation of GRP78 expression in KB cells and increased the expression of activated caspase-3.

CONCLUSIONMetformin can inhibit the proliferation and induce apoptosis of KB cells, the mechanism of which may involve the activation of the mitochondrial apoptotic pathway and endoplasmic reticulum stress.

Apoptosis ; drug effects ; Caspase 3 ; metabolism ; Cell Proliferation ; drug effects ; Heat-Shock Proteins ; metabolism ; Humans ; KB Cells ; Membrane Potential, Mitochondrial ; drug effects ; Metformin ; pharmacology

This study investigated the antimicrobial activity of methanol extract of mulberry leaf against 16 strains of mutans streptococci and four species of periodontopathogens: Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, and Aggregatibacter actinomycetemcomitans. The antimicrobial activities of the crude extracts or silica gel chromatography fractions of methanol-extracted mulberry leaf were evaluated by determining minimal inhibitory concentrations using an established microdilution method. The cytotoxicity of the extracts of mulberry leaf on KB cells was tested by the methyl thiazolyl tetrazolium assay. Chromatography fraction 12 displayed the most potent antimicrobial activity against all 16 strains of mutans streptococci, P. gingivalis, and P. intermedia. No KB cell cytotoxicity was evident up to 128 microg/ml of fraction 12. The methanol extract had no antimicrobial activity against F. nucleatum and A. actinomycetemcomitans. These results suggest chromatography fraction 12 methanol extract of mulberry leaf could be useful in the development of oral hygiene products, such as dentifrice and oral hygiene solution, for the prevention of dental caries.
Aggregatibacter actinomycetemcomitans ; Chromatography ; Complex Mixtures ; Dental Caries ; Dentifrices ; Fusobacterium nucleatum ; Humans ; KB Cells ; Methanol ; Morus* ; Oral Hygiene ; Porphyromonas gingivalis ; Prevotella intermedia ; Silica Gel

OBJECTIVETo investigate the effect of small interfering RNA (siRNA)-mediated COX-2 gene silencing in enhancing the chemosensitivity of KB/VCR cell lines.

METHODSKB/VCR cells were trasnfected with COX-2 siRNA were examined for expressions of COX-2 and MDR-1 mRNAs with RT-PCR and for Rho-123 accumulation using flow cytometry. MTT assay was used to analyze the proliferation of the transfected KB/VCR cells.

RESULTSCompared with the negative and blank control groups, COX-2 siRNA transfection resulted in significant growth inhibition of KB/VCR cells exposed to vincristine (P<0.01), down-regulated the expressions of COX-2 and MDR-1 mRNAs, and obviously increased Rho-123 accumulation in KB/VCR cells.

CONCLUSIONCOX-2 gene silencing can enhance the chemosensitivity of KB/VCR cells to vincristine, the mechanism of which may involve down-regulated MDR-1 gene expression and inhibition of P-glycoprotein activity.

ATP Binding Cassette Transporter, Sub-Family B ; genetics ; metabolism ; Cyclooxygenase 2 ; genetics ; metabolism ; Drug Resistance, Neoplasm ; genetics ; Gene Expression Regulation, Neoplastic ; Gene Silencing ; Humans ; KB Cells ; RNA, Messenger ; RNA, Small Interfering ; Transfection ; Vincristine

OBJECTIVETo investigate the effect of celecoxib in enhancing the chemosensitivity of oral cancer cells and the correlation of this effect with cell cycle arrest.

METHODSKB/VCR cell line was treated with celecoxib (10, 20, 40, and 80 µmol/L) and/or VCR (0.375, 0.75, 1.5, and 3 µmol/L), and the growth inhibition rates of KB/VCR cells were assessed with MTT assay. Flow cytometry was employed to analyze the distribution of cell cycle. Western blotting was performed to detect the expression of P-glycoprotein (P-gp) and the cell cycle related proteins Cyclin D1 and p21(WAF1/CIP1).

RESULTSLow concentrations of celecoxib (<20 µmol/L) produced no obvious effect on the proliferation of the cells. But at 10 µmol/L, celecoxib significantly enhanced the toxicity of VCR in a time-dependent manner, and the combined treatments for 24, 48, and 72 h caused growth inhibition rates of (37.53∓2.05)%, (46.67∓3.17)% and (54.02∓1.53)%, respectively, significantly higher than those following treatments with celecoxib or VCR alone (P<0.01). Compared with the cells treated with VCR alone , the cells with combined treatments showed a significantly increased cell percentage in G0/G1 phase [(56.08∓0.46)%] with decrease percentages in S phase [(22.83∓0.20)%] and G2/M phase [(21.09%∓0.66)%]. The combined treatment also significantly down-regulated cyclin D1, up-regulated p21(WAF1/CIP1), and reduced P-gp expressions in the cells.

CONCLUSIONSCelecoxib enhances the chemosensitivity of KB/VCR cells by down-regulating P-gp expression, which is partially mediated by modification of cyclin D1 and p21(WAF1/CIP1) to result in cell cycle arrest.

ATP-Binding Cassette, Sub-Family B, Member 1 ; metabolism ; Celecoxib ; Cell Cycle ; drug effects ; Cell Line, Tumor ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p21 ; metabolism ; Drug Resistance, Neoplasm ; drug effects ; Humans ; KB Cells ; Mouth Neoplasms ; drug therapy ; metabolism ; Pyrazoles ; pharmacology ; Sulfonamides ; pharmacology

S1-M1-80 cells, derived from human colon carcinoma S1 cells, are mitoxantrone-selected ABCG2-overexpressing cells and are widely used in in vitro studies of multidrug resistance(MDR). In this study, S1-M1-80 cell xenografts were established to investigate whether the MDR phenotype and cell biological properties were maintained in vivo. Our results showed that the proliferation, cell cycle, and ABCG2 expression level in S1-M1-80 cells were similar to those in cells isolated from S1-M1-80 cell xenografts (named xS1-M1-80 cells). Consistently, xS1-M1-80 cells exhibited high levels of resistance to ABCG2 substrates such as mitoxantrone and topotecan, but remained sensitive to the non-ABCG2 substrate cisplatin. Furthermore, the specific ABCG2 inhibitor Ko143 potently sensitized xS1-M1-80 cells to mitoxantrone and topotecan. These results suggest that S1-M1-80 cell xenografts in nude mice retain their original cytological characteristics at 9 weeks. Thus, this model could serve as a good system for further investigation of ABCG2-mediated MDR.
ATP Binding Cassette Transporter, Sub-Family G, Member 2 ; ATP-Binding Cassette Transporters ; antagonists & inhibitors ; metabolism ; Adenosine ; analogs & derivatives ; pharmacology ; Animals ; Antineoplastic Agents ; pharmacology ; Cell Cycle ; Cell Line, Tumor ; Cell Proliferation ; Cell Survival ; drug effects ; Cisplatin ; pharmacology ; Colonic Neoplasms ; metabolism ; pathology ; Diketopiperazines ; Doxorubicin ; metabolism ; Drug Resistance, Multiple ; Drug Resistance, Neoplasm ; Female ; Heterocyclic Compounds, 4 or More Rings ; Humans ; Inhibitory Concentration 50 ; KB Cells ; Male ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Mitoxantrone ; pharmacology ; Neoplasm Proteins ; antagonists & inhibitors ; metabolism ; Neoplasm Transplantation ; Rhodamine 123 ; metabolism ; Topotecan ; pharmacology