BACKGROUNDSurfactant protein-A (SP-A) contributes to the regulation of sepsis-induced acute kidney injury. In a previous study, we demonstrated that the expression of SP-A in the human renal tubular epithelial (HK-2) cells can be stimulated by lipopolysaccharide (LPS). The present study evaluated the possible signal-transducing mechanisms of LPS-induced SP-A biosynthesis in the HK-2 cells.

METHODSTetrazolium salt colorimetry (MTT) assay was used to detect cell viability of HK-2 cells after LPS stimulation on different time points. HK-2 cells were stimulated with 100 ng/ml of LPS for different durations to determine the effects of LPS on SP-A and toll-like receptor 4 (TLR4) messenger RNA (mRNA) expression, as well as phosphorylation of mitogen-activated/extracellular signal-regulated kinase (MEK) 1, extracellular signal-regulated kinase 1/2 (ERK1/2), p38 mitogen-activated protein kinase (p38MAPK), and nuclear factor-kappa B (NF-κB) inhibitor-alpha (IkB-α). Then, HK-2 cells were pretreated with CLI-095, a TLR4 inhibitor, to analyze mRNA and protein levels of SP-A and TLR4 and expression of NF-κB in the cytoplasm and nucleus of HK-2 before LPS exposure.

RESULTSHK-2 cells exposed to 100 ng/ml of LPS for 1, 6, and 24 h did not affect cell viability which showed no toxic effect of 100 ng/ml LPS on cells (P = 0.16); however, the biosynthesis of SP-A mRNA and protein in HK-2 cells was significantly increased (P = 0.02). As to the mechanism, LPS enhanced transmembrane receptor TLR4 protein expression. Sequentially, LPS time dependently augmented phosphorylation of MEK1, ERK1/2, and p38MAPK. In addition, levels of phosphorylated IκB-α and nuclear NF-κB were augmented with LPS exposure for 2 h. LPS-induced SP-A and TLR4 mRNA as well as NF-κB expression were significantly inhibited by pretreatment with CLI-095.

CONCLUSIONSThe present study exhibited that LPS can increase SP-A synthesis in human renal epithelial cells through sequentially activating the TLR4-related MEK1-ERK1/2-NF-κB-dependent pathway.

Cell Line ; Cell Survival ; drug effects ; physiology ; Colorimetry ; Humans ; Kidney ; cytology ; metabolism ; Lipopolysaccharides ; toxicity ; Mitogen-Activated Protein Kinase 1 ; metabolism ; Mitogen-Activated Protein Kinase 3 ; metabolism ; NF-kappa B ; metabolism ; Pulmonary Surfactant-Associated Protein A ; metabolism ; Sulfonamides ; pharmacology ; Tetrazolium Salts ; chemistry ; Toll-Like Receptor 4 ; antagonists & inhibitors ; metabolism

OBJECTIVE: To assess magnetic resonance imaging (MRI) features of coronary microembolization in a swine model induced by small-sized microemboli, which may cause microinfarcts invisible to the naked eye. MATERIALS AND METHODS: Eleven pigs underwent intracoronary injection of small-sized microspheres (42 microm) and catheter coronary angiography was obtained before and after microembolization. Cardiac MRI and measurement of cardiac troponin T (cTnT) were performed at baseline, 6 hours, and 1 week after microembolization. Postmortem evaluation was performed after completion of the imaging studies. RESULTS: Coronary angiography pre- and post-microembolization revealed normal epicardial coronary arteries. Systolic wall thickening of the microembolized regions decreased significantly from 42.6 +/- 2.0% at baseline to 20.3 +/- 2.3% at 6 hours and 31.5 +/- 2.1% at 1 week after coronary microembolization (p < 0.001 for both). First-pass perfusion defect was visualized at 6 hours but the extent was largely decreased at 1 week. Delayed contrast enhancement MRI (DE-MRI) demonstrated hyperenhancement within the target area at 6 hours but not at 1 week. The microinfarcts on gross specimen stained with nitrobluetetrazolium chloride were invisible to the naked eye and only detectable microscopically. Increased cTnT was observed at 6 hours and 1 week after microembolization. CONCLUSION: Coronary microembolization induced by a certain load of small-sized microemboli may result in microinfarcts invisible to the naked eye with normal epicardial coronary arteries. MRI features of myocardial impairment secondary to such microembolization include the decline in left ventricular function and myocardial perfusion at cine and first-pass perfusion imaging, and transient hyperenhancement at DE-MRI.
Animals ; Coronary Angiography/*methods ; Coronary Vessels/*pathology ; Disease Models, Animal ; Embolism/*pathology ; Female ; Heart/radiography ; Image Processing, Computer-Assisted ; Magnetic Resonance Imaging/*methods ; Microspheres ; Myocardial Contraction/physiology ; Myocardial Infarction/*pathology ; Myocardium/pathology ; Nitroblue Tetrazolium ; Staining and Labeling ; Swine ; Troponin T/blood ; Ventricular Function, Left

OBJECTIVETo determine the effect of aspirin on cell proliferation, alkaline phosphatase (ALP) activity, cell cycle and apoptosis in murine bone marrow stromal cells, so as to explore an appropriate dose range to improve bone regeneration in periodontal treatment.

METHODSST2 cells were stimulated with aspirin (concentrations of 1, 10, 100 and 1 000 μmol/L) for 1, 2, 3, 5 and 7 d. Cell proliferation was measured by methyl thiazolyl tetrazolium (MTT) assay. After ST2 cells were treated for 1, 3 and 7 d, ALP activity was measured by ALP kit, cell cycle and apoptosis were measured by flow cytometry (FCM) after treated for 48 h.

RESULTSMTT assays showed that various doses of aspirin have different effects on the cell growth. Briefly, lower concentrations (1, 10 μmol/L) of aspirin promoted the cell growth, the A value of 0, 1 and 10 μmol/L aspirin 7-day-treated cells were 0.313±0.012, 0.413±0.010 and 0.387±0.017 respectively (P <0.01 vs control), and so did the ALP level ([4.3±0.9], [6.0±0.3] and [7.7±0.4] μmol·min(-1)·g(-1), P <0.05 vs control), while higher concentrations, especially 1000 μmol/L of aspirin might inhibit the cell growth with time going, A value and ALP level were 0.267±0.016, (4.3±1.3) μmol·min(-1)·g(-1) respectively (P <0.05 vs control). Cell cycle analysis revealed no changes in comparison to control cells after treatment with 1 or 10 μmol/L aspirin, but it was observed that cell mitosis from S phase to G2/M phase proceeded at higher concentrations of 100 μmol/L aspirin, and the cell cycle in phase G0/G1 arrested at 1000 μmol/L. Parallel apoptosis/necrosis studies showed that the percentage of cells in apoptosis decreased dramatically at all doses of aspirin, the apoptosis rates of ST2 cells responded to 0, 1, 10, 100 and 1000 μmol/L aspirin were (11.50±0.90)%, (5.30±0.10)%, (5.50±0.10)%, (4.90±0.90)% and (7.95±0.25)% respectively (P<0.05 vs control).

CONCLUSIONSThis study demonstrated that lower dosage of aspirin can promote ST2 cells growth, osteogenic activity and inhibit its apoptosis. Aspirin maybe used for the bone reconstruction with a proper concentration.

Alkaline Phosphatase ; metabolism ; Animals ; Apoptosis ; drug effects ; Aspirin ; administration & dosage ; pharmacology ; Bone Regeneration ; Cell Cycle ; drug effects ; Cell Division ; Cell Line, Tumor ; Cell Proliferation ; Flow Cytometry ; Formazans ; Mesenchymal Stromal Cells ; cytology ; drug effects ; enzymology ; Mice ; Periodontics ; Tetrazolium Salts ; Time Factors

OBJECTIVETo explore the antitumoral effect of indirubin on androgen-independent prostate cancer PC-3 cells and its possible mechanisms.

METHODSWe measured the inhibitory effect of indirubin on the proliferation of prostate cancer PC-3 cells using MTT assay, detected their cell cycles by flow cytometry, and determined the expressions of the cell cycle regulatory protein cyclin D1 and its related downstream gene c-myc by Western blot.

RESULTSThe viability of the PC-3 cells was significantly decreased by indirubin in a concentration-dependent manner, reduced to 52. 2% and 13. 6% at 5 and 10 µmol/L, respectively. The cell cycle of the PC-3 cells was markedly inhibited by indirubin at 5 µmol/L, with the cells remarkably increased in the G0 and G1 phases and decreased in the S and G2/M phases. Meanwhile, indirubin also inhibited the expressions of cyclin D1 and c-myc in the Wnt signaling pathway.

CONCLUSIONIndirubin can suppress the proliferation of androgen-independent prostate cancer PC-3 cells, which may be associated with its inhibitory effect on the cell cycle and Wnt signaling pathway.

Antibiotics, Antineoplastic ; administration & dosage ; pharmacology ; Cell Cycle ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cell Survival ; drug effects ; Coloring Agents ; Cyclin D1 ; metabolism ; Dose-Response Relationship, Drug ; Genes, myc ; Humans ; Indoles ; administration & dosage ; pharmacology ; Male ; Prostatic Neoplasms, Castration-Resistant ; drug therapy ; pathology ; Proto-Oncogene Proteins c-myc ; metabolism ; Tetrazolium Salts ; Thiazoles

OBJECTIVETo investigate the effect of CAL-101, a selective inhibitor of PI3Kδ, in combination with bortezomib on the proliferation and apoptosis in human mantle cell lymphoma cell lines Z138, HBL-2 and Jeko-1 in vitro, to explore its mechanisms and provide the foundation for effective treatment strategies against mantle cell lymphoma.

METHODSMTT assay was applied to detect the inhibitory effects of CAL-101 and bortezomib either alone or combined on Z138, HBL-2 and Jeko-1 cells. Calcusyn software was used to analyze the synergistic cytotoxicity. Western blot was used to detect the expression of PI3K-p110σ and p-Akt, Akt, p-ERK and ERK proteins after the cells were exposed to different concentrations of CAL-101. Flow cytometry was employed to assess the apoptosis rate. NF-κB kit was used to determine the changes of location of NF-κB P65, and Western blot was applied to detect the level of caswpase-3 and the phosphorylation of Akt in different groups.

RESULTSCAL-101 and BTZ inhibited the proliferation of Z138, HBL-2 and Jeko-1 cells in a dose- and time-dependent manner. CAL-101/BTZ combination induced significantly synergistic cytotoxicity in the MCL cells. The results of Western blot assay showed that CAL-101 significantly blocked the phosphorylation of Akt and ERK in the MCL cell lines. In addition, CAL-101 combined with BTZ induced pronounced apoptosis (P < 0.01). For example, after the Z138 cells exposed to the drugs for 48 h, the apoptosis rates of the control, CAL-101, BTZ and CAL-101 + BTZ groups were: (2.6 ± 1.8)%, (40.0 ± 3.0)%, (34.0 ± 1.0)%, and (67.4 ± 1.0)%, respectively; and when drug treatment was given to HBL-2 cells over 96 h, the apoptosis rates of these four cell groups were (7.4 ± 0.6)%, (30.7 ± 5.7)%, (12.0 ± 1.0)%, and (85.0 ± 4.0)%, respectively. The combination therapy contributed to the enhanced inactivity of nuclear factor-κB (NF-κB) and Akt inactivation in the MCL cell lines (P < 0.05), however, the casepase-3 activity was up-regulated.

CONCLUSIONSThe combination of CAL-101 and bortezomib is muchmore effective in inhibiting proliferation and promoting apoptosis of mantle cell lymphoma cell lines (Z138, HBL-2 and Jeko-1), which may be mediated through inhibiting PI3K/Akt signaling pathway and the transcription of NF-κB.

Antineoplastic Agents ; pharmacology ; Antineoplastic Combined Chemotherapy Protocols ; pharmacology ; Apoptosis ; drug effects ; Blotting, Western ; Boronic Acids ; Bortezomib ; pharmacology ; Caspase 3 ; metabolism ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Class Ia Phosphatidylinositol 3-Kinase ; antagonists & inhibitors ; Dose-Response Relationship, Drug ; Drug Synergism ; Formazans ; Humans ; Lymphoma, Mantle-Cell ; drug therapy ; pathology ; MAP Kinase Signaling System ; drug effects ; NF-kappa B ; metabolism ; Neoplasm Proteins ; metabolism ; Phosphatidylinositol 3-Kinases ; metabolism ; Phosphorylation ; drug effects ; Proto-Oncogene Proteins c-akt ; metabolism ; Purines ; administration & dosage ; pharmacology ; Pyrazines ; Quinazolinones ; administration & dosage ; pharmacology ; Signal Transduction ; Software ; Tetrazolium Salts

OBJECTIVETo study the molecular mechanism of cisplatin to enhance the ability of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in reversing multidrug resistance in vincristine-resistant human gastric cancer SGC7901/VCR cells.

METHODSMTT assay was used to measure the 50% inhibiting concentration (IC₅₀) and cell survival in SGC7901 and SGC7901/VCR cells after different treatments. SGC7901/VCR cells were treated with different concentrations of DDP, different concentrations of TRAIL alone or in combination, and then the mRNA and protein levels of several genes were determined by RT-PCR, RT-qPCR and Western-blot analysis. After targeted silencing with specific siRNA and transfection of recombinant plasmid c-myc into the SGC7901/VCR cells, the mRNA and protein levels of DR4, DR5 and c-myc were determined by RT-PCR and Western-blot analysis.

RESULTSAfter combined treatment with TRAIL and DDP of the SGC7901/VCR cells, the IC₅₀ of VCR, DDP, ADM, and 5-Fu treatment was significantly decreased compared with the control group or TRAIL-treated group (P < 0.05). After treatment with 0, 10, 50 ng/ml TRAIL in combination with 0.4 µg/ml DDP, the SGC7901/VCR cells showed significantly higher activation of caspase 3, down-regulation of DNA-PKcs/Akt/GSK-3β signaling pathway, and higher inhibition of MDR1(P-gp) and MRP1 than those treated with TRAIL alone (P < 0.01 for all). The mRNA and protein levels of DR4, DR5, c-myc were significantly decreased after silencing c-myc with specific siRNA in the SGC7901/VCR cells (P < 0.01 for all), and were significantly increased after transfection of recombinant plasmid c-myc into the SGC7901/VCR cells (P < 0.01 foe all). After the treatment with 10 ng/ml TRAIL, 0.25 µg/ml DDP + 10 ng/ml TRAIL and 0.5 µg/ml DDP + 10 ng/ml TRAIL, the relative expression level of c-myc protein in the SGC7901/VCR cells was 0.314 ± 0.012, 0.735 ± 0.026, and 0.876 ± 0.028, respectively, and the relative expression of cytochrome C was 0.339 ± 0.036, 0.593 ± 0.020 and 0.735 ± 0.031, respectively, and the relative expression levels of DR4, DR5, active-caspase 3 and active-caspase 9 in the SGC7901/VCR cells were also increased along with increasing DDP concentrations.

CONCLUSIONSThe activation of DNA-PKcs/Akt/GSK-3β signaling pathway and high expression of MDR1 and MRP1 play an important role in the multi-drug resistance properties of SGC7901/VCR cells. After combining with TRAIL, DDP can enhance the expression of DR4 and DR5 through up-regulating c-myc and enhancing the activation of caspase 3 and caspase 9 by facilitating mitochondrial release of cytochrome C. It may be an important molecular mechanism of DDP-induced sensitization of TRAIL to reverse the multidrug resistancein SGC7901/VCR cells.

ATP-Binding Cassette, Sub-Family B, Member 1 ; metabolism ; Antineoplastic Agents ; administration & dosage ; pharmacology ; Antineoplastic Combined Chemotherapy Protocols ; administration & dosage ; pharmacology ; Caspase 3 ; metabolism ; Caspase 9 ; metabolism ; Cell Line, Tumor ; Cisplatin ; administration & dosage ; pharmacology ; Down-Regulation ; Drug Resistance, Multiple ; drug effects ; Drug Resistance, Neoplasm ; drug effects ; Fluorouracil ; administration & dosage ; pharmacology ; Formazans ; Genes, myc ; Glycogen Synthase Kinase 3 ; metabolism ; Glycogen Synthase Kinase 3 beta ; Humans ; Inhibitory Concentration 50 ; Multidrug Resistance-Associated Proteins ; metabolism ; Neoplasm Proteins ; metabolism ; Plasmids ; Proto-Oncogene Proteins c-myc ; metabolism ; RNA, Messenger ; metabolism ; RNA, Small Interfering ; pharmacology ; Receptors, TNF-Related Apoptosis-Inducing Ligand ; metabolism ; Stomach Neoplasms ; drug therapy ; pathology ; TNF-Related Apoptosis-Inducing Ligand ; administration & dosage ; pharmacology ; Tetrazolium Salts ; Transfection ; methods

OBJECTIVETo investigate the effect of estrogen (E2), progesterone(P4), and paclitaxel (taxol) on the growth of primary human ovarian cancer cells in vitro and the expression of Drosha.

METHODSHuman ovarian cancer cells were treated with estrogen, progesterone or in combination with paclitaxel in vitro. The inhibition rate of ovarian cancer cells was assessed by methyl thiazolyl tetrazolium (MTT) assay. Apoptosis rate and cell cycle were determined by FACS analysis. The relative abundence of Drosha expression was detected by real-time quantitative PCR (qRT-PCR) and Western blotting.

RESULTSThe inhibition rate of the estrogen group, progesterone group, paclitaxel group, E2(+)Taxol group, P4(+)Taxol group was (31.53 ± 8.21)%, (25.22 ± 15.50)%, (46.71 ± 4.25)%, (69.46 ± 3.71)%, and (47.35 ± 39.02)%, respectively, significantly higher than that of the control group (0%, P<0.05 for all). Relative to the ER (-) in ovarian cancer cells,Drosha mRNA expression level of estrogen group, progesterone group, paclitaxel group, E2(+) Taxol group,and P4(+)Taxol group was 1.62 ± 0.10,1.60 ± 0.10,1.75 ± 0.16,1.95 ± 0.20, and 1.53 ± 0.06, respectively, significantly higher than that of the control group (1.00, P<0.05 for all). Relative to the ER (+)in ovarian cancer cells,the Drosha mRNA expression level of estrogen group, progesterone group, paclitaxel group, E2(+)taxol group, and P4(+)Taxol group was 1.03 ± 0.14, 1.60 ± 0.09, 1.75 ± 0.16, 1.60 ± 0.10, 1.53 ± 0.06, respectively except estrogen group, significantly higher than that of the control group (1.00, P<0.05). Relative to the ER (-) in ovarian cancer cells, the Drosha protein expression levels of the control group, estrogen group, progesterone group, paclitaxel group, E2(+) taxol group, and P4(+) Taxol group were 0.25 ± 0.05, 0.87 ± 0.30, 0.85 ± 0.38, 1.30 ± 0.21, 1.75 ± 0.83, 1.62 ± 0.82, respectively, with a significant difference between the experimental groups and the control group (P<0.05). Relative to the ER(+)ovarian cancer cells, the Drosha protein expression levels in the estrogen group, progesterone group, paclitaxel group, E2(+) taxol group, and P4(+) taxol group, were 0.28 ± 0.16, 0.85 ± 0.38, 1.30 ± 0.21, 0.94 ± 0.18, and 1.62 ± 0.82, respectively except estrogen group, significantly higher than that of the control group (0.25 ± 0.05, P<0.05 for all).

CONCLUSIONSEstrogen and progesterone in combination with paclitaxel can inhibit the growth of human ovarian cancer cells in vitro, and affect the cell apoptosis rate. Estrogen and taxol can alter the cell cycle. Estrogen and progesterone combined with paclitaxel show tumor suppressing or sensitizing effect through upregulated Drosha expression, and are associated with the estrogen receptor expression.

Antineoplastic Agents, Phytogenic ; pharmacology ; Antineoplastic Combined Chemotherapy Protocols ; pharmacology ; Apoptosis ; Cell Cycle ; Cell Growth Processes ; drug effects ; Cell Line, Tumor ; Coloring Agents ; Drug Therapy, Combination ; Estrogens ; pharmacology ; Female ; Humans ; In Vitro Techniques ; Ovarian Neoplasms ; chemistry ; drug therapy ; metabolism ; pathology ; Paclitaxel ; pharmacology ; Progesterone ; pharmacology ; RNA, Messenger ; metabolism ; Receptors, Estrogen ; metabolism ; Ribonuclease III ; genetics ; metabolism ; Tetrazolium Salts ; Thiazoles ; Up-Regulation

OBJECTIVETo investigate the effects of bufalin in reversing hepatocyte growth factor (HGF)-induced resistance to afatinib in H1975 lung cancer cells, and explore its possible mechanism.

METHODSThe afatinib-resistant H1975 lung cancer cells (H1975AR) were induced by exogenous HGF and transfected with recombinant adenoviral vector Ad-HGF-GFP. The cytostatic effects of bufalin, afatinib and bufalin plus afatinib on H1975AR cells were evaluated by MTT assay. The impact of combined therapy with bufalin and afatinib on invasion of H1975AR cells was determined by transwell migration assay. The concentrations of HGF in the culture supernatants of H1975/Vec and H1975/HGF cells were determined by ELISA. The expression of EGFR, cMET and EMT signal pathway-related proteins in H1975AR cells treated with bufalin, afatinib and bufalin plus afatinib were detected by Western blot.

RESULTSThe results of MTT assay showed that afatinib did not inhibit the growth of H1975 cells, but after 72 h of the combined treatment with bufalin and afatinib and in the presence of HGF, the growth rate of H1975 cells was (38.67 ± 8.76)%, significantly lower than the growth rate of (63.45 ± 12.65)% in the H1975 cells treated with HGF alone (P < 0.05). The results of transwell migration assay showed that in the presence of HGF, afatinib plus bufalin combination therapy markedly decreased the number of invaded H1975 cells through the Matrigel chamber (48.98 ± 11.43), significantly lower than the 118.92 ± 37.29 of afatinib-treated or the 88.84 ± 19.53 of bufalin-treated cells (P < 0.05 for all). The result of ELISA showed that H1975/HGF cells secreted high levels of HGF, and afatinib and bufalin had no effect on the HGF secretion in H1975/HGF cells. The results of Western blot analysis showed that the expression of p-EGFR, p-cMet, p-AKT, p-ERK, vimentin and snail in H1975AR cells treated with bufalin puls afatinb was down-regulated markedly, and the expression of E-cadherin was up-regulated markedly.

CONCLUSIONSCombination of bufalin and afatinib strongly inhibits the growth of H1975AR lung cancer cells and decreases their invasion ability. The possible mechanism of combined treatment with bufalin and afatinib may be related to the blocking of cMet/PI3K/AKT and cMet/MAPK/ERK pathways and inhibiting of epithelial-mesenchymal transition.

Antineoplastic Agents ; pharmacology ; Antineoplastic Combined Chemotherapy Protocols ; pharmacology ; Bufanolides ; pharmacology ; Cadherins ; metabolism ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Coloring Agents ; Drug Resistance, Neoplasm ; drug effects ; Epithelial-Mesenchymal Transition ; drug effects ; Hepatocyte Growth Factor ; pharmacology ; Humans ; Lung Neoplasms ; drug therapy ; metabolism ; pathology ; MAP Kinase Signaling System ; Neoplasm Proteins ; metabolism ; Phosphatidylinositol 3-Kinases ; Quinazolines ; pharmacology ; Receptor, Epidermal Growth Factor ; Signal Transduction ; Tetrazolium Salts ; Thiazoles

MTT assay is commonly used to assess the cellular cytotoxicity caused by anticancer drugs in glioblastomas. However, there have been some reports insisting that MTT assay exhibited non-specific intracellular reduction of tetrazolium which led to underestimated results of cytotoxicity. Here, we examine whether or not MTT assay can lead to incorrect information regarding alcohol-induced cytotoxicity on immortalized and primary glioblastoma cells. MTT assay was applied to assess the ethanol-induced cytotoxicity at various ethanol concentrations. The cellular cytotoxicity induced by different doses of ethanol was analyzed and compared through several cytotoxic assays. Ethanol-induced cytotoxicity observed through MTT assay on both cell types was shown to be ethanol dose-dependent below a 3% concentration. However, the cytotoxicity was shown to be markedly underestimated only in primary cells at a 5% concentration. RT-PCR and Western Blot showed increased expressions of pro-apoptotic proteins and decreased expressions of anti-apoptotic proteins in an ethanol dose-dependent manner in both cell types. Furthermore, we present a possible mechanism for the unreliable result of MTT assay. A high concentration of ethanol induces more severe membrane damage and increased intracellular concentration of NADH in primary cells which enhances the nonspecific reduction of tetrazolium salt. Together, our findings demonstrate that the cytotoxicity on primary cells could inaccurately be assessed when detected through MTT assay. Therefore, a careful interpretation is needed when one would analyze the cytotoxic results of MTT assay, and it is suggested that other assays must be accompanied to produce more reliable and accurate cytotoxic results on primary glioblastoma cells.
Apoptosis Regulatory Proteins ; Blotting, Western ; Ethanol ; Glioblastoma* ; Membranes ; NAD ; Tetrazolium Salts

The objective of the study was to analyse Streptococcus mutans biofilms grown under different dietary conditions by using multifaceted methodological approaches to gain deeper insight into the cariogenic impact of carbohydrates. S. mutans biofilms were generated during a period of 24 h in the following media: Schaedler broth as a control medium containing endogenous glucose, Schaedler broth with an additional 5% sucrose, and Schaedler broth supplemented with 1% xylitol. The confocal laser scanning microscopy (CLSM)-based analyses of the microbial vitality, respiratory activity (5-cyano-2,3-ditolyl tetrazolium chloride, CTC) and production of extracellular polysaccharides (EPS) were performed separately in the inner, middle and outer biofilm layers. In addition to the microbiological sample testing, the glucose/sucrose consumption of the biofilm bacteria was quantified, and the expression of glucosyltransferases and other biofilm-associated genes was investigated. Xylitol exposure did not inhibit the viability of S. mutans biofilms, as monitored by the following experimental parameters: culture growth, vitality, CTC activity and EPS production. However, xylitol exposure caused a difference in gene expression compared to the control. GtfC was upregulated only in the presence of xylitol. Under xylitol exposure, gtfB was upregulated by a factor of 6, while under sucrose exposure, it was upregulated by a factor of three. Compared with glucose and xylitol, sucrose increased cell vitality in all biofilm layers. In all nutrient media, the intrinsic glucose was almost completely consumed by the cells of the S. mutans biofilm within 24 h. After 24 h of biofilm formation, the multiparametric measurements showed that xylitol in the presence of glucose caused predominantly genotypic differences but did not induce metabolic differences compared to the control. Thus, the availability of dietary carbohydrates in either a pure or combined form seems to affect the cariogenic potential of S. mutans biofilms.
Bacterial Load ; drug effects ; Bacteriological Techniques ; Biofilms ; drug effects ; Cariogenic Agents ; metabolism ; pharmacology ; Culture Media ; Dental Enamel ; microbiology ; Fluorescent Dyes ; Gene Expression Regulation, Bacterial ; drug effects ; Gene Expression Regulation, Enzymologic ; drug effects ; Genotype ; Glucose ; metabolism ; Glucosyltransferases ; metabolism ; Humans ; Microbial Viability ; drug effects ; Microscopy, Confocal ; Polysaccharides, Bacterial ; biosynthesis ; Streptococcus mutans ; drug effects ; enzymology ; metabolism ; Sucrose ; metabolism ; pharmacology ; Sweetening Agents ; metabolism ; pharmacology ; Tetrazolium Salts ; Time Factors ; Up-Regulation ; Xylitol ; metabolism ; pharmacology