OBJECTIVETo investigate the effects of LPS and/or TNF-alpha on periodontal ligament cell (PDLC) proliferation and OPG secretion.

METHODSHealthy premolars extracted for orthodontic reasons from a 12 years old boy were obtained, and periodontal tissues were collected and cultured to obtain PDLCs. Cloned PDLCs were obtained by means of limited dilutions, and were characterized as follows: alkaline phosphatase activity, collagen III production and bone-like nodules formation. LPS and rhTNF-alpha were added into culture media and their effects on PDLC proliferation and OPG secretion were observed. The OPG concentrations in cell culture supernatants were detected by sandwich ELISA. Living cell numbers were demonstrated by MTT test. The average levels of OPG secretion by a single cell were calculated by dividing OPG concentration with MTT result.

RESULTSrhTNF-alpha above 10 micro g/L decreased the mtt and opg detecting results, but increased the opg/mtt values (P < 0.05). However, LPS had no effect on mtt, opg or opg/mtt values. Neither it had any interaction with rhTNF-alpha (P > 0.05).

CONCLUSIONSTNF-alpha prohibits the proliferation of PDLCs but enhances their OPG secretion. However, LPS has no effect on neither side. Our works support the hypothesis that there may be an inverse feedback regulation pattern of increasing periodontal OPG production against local bone resorption activity. PDLCs might not be the natural target cells of LPS' direct cytotoxic effect.

Child ; Glycoproteins ; biosynthesis ; drug effects ; Humans ; In Vitro Techniques ; Lipopolysaccharides ; pharmacology ; Male ; Osteoprotegerin ; Periodontal Ligament ; metabolism ; pathology ; Receptors, Cytoplasmic and Nuclear ; biosynthesis ; drug effects ; Receptors, Tumor Necrosis Factor ; biosynthesis ; drug effects ; Tumor Necrosis Factor-alpha ; pharmacology

OBJECTIVETo express human osteoprotegerin (OPG) in E. Coli and analyze its bioactivity in vitro.

METHODSSynthetic oligonucleotides were used to amplify human OPG gene by RT-PCR from total RNA of human osteosarcoma cell line MG63. The OPG cDNA coding for 380 amino acid residues was inserted into prokaryotic expression vector pRSET-A, transformed into competent E. Coli BL21, and induced by 0.1 mmol/l IPTG. SDS-PAGE and Western blot were performed to identify OPG-6His fusion protein. After purified by affinity chromatography, 1,000 microg/L or 1,500 microg/L of OPG-6His were added into the mouse bone marrow cells culture medium. The number of tartrate-resistant acid phophatase (TRAP)-positive multinucleated cells and resorption pits were counted to assess the bioactivity of expression products.

RESULTSThe sequence of OPG mature peptide encoding cDNA obtained in this experiment was as same as reported. SDS-PAGE showed 24% of total bacterial protein was of OPG-6His fusion protein. Western blot assay demonstrated that the molecular weight of recombinant protein was about 46 KD and could react specifically with human anti-OPG antibody. The mouse bone marrow cells were induced by 1alpha, 25-dihydroxyvitaminD3 (10(-8) mol/L) and Dexamethasone (10(-7) mol/L) to form osteoclastic-like multinucleated cells. 1,500 microg/L of purified OPG-6His protein could decrease the number of resorption pits and TRAP-positive multinucleated cells in vitro (P < 0.05), but it didn't show the same effects when the concentration of OPG-6His fusion protein was of 1,000 microg/L.

CONCLUSIONSHuman OPG-6His fusion protein is expressed and purified in E. Coli. The expression products have moderate inhibitory effects on osteoclast differentiation and bone resorption in vitro only when excessive amount of proteins are added into the culture medium, indicating that prokaryotic expression of fuctionalal OPG protein awaits further investigation.

Cell Differentiation ; drug effects ; Cell Line, Tumor ; Cloning, Molecular ; Escherichia coli ; genetics ; Glycoproteins ; biosynthesis ; genetics ; Humans ; Osteoclasts ; drug effects ; physiology ; Osteoprotegerin ; Receptors, Cytoplasmic and Nuclear ; biosynthesis ; genetics ; Receptors, Tumor Necrosis Factor ; Recombinant Fusion Proteins ; biosynthesis ; pharmacology

OBJECTIVETo detect the expression of recombinant plasmid PcDNA3.1-sTNFRI in vitro and evaluate the bioactivity of expressed sTNFRI.

METHODSCHO cells were transfected with recombinant plasmid PcDNA3.1-sTNFRI by liposome. sTNFRI in cell culture supernatant was detected by ELISA and sTNFRI blockage of TNF-alpha cytotoxicity in L929 cells evaluated by MTT assay.

RESULTSThe expression of sTNFRI in transfected cell culture supernatant was higher than control groups (P < 0.001). The expressed sTNFRI could significantly neutralize TNF-alpha cytotoxicity in L929 cells.

CONCLUSIONSThese results showed that the recombinant plasmid PcDNA3.1-sTNFRI can be expressed in mammalian cells and the recombinant sTNFRI has biological function.

Animals ; Antigens, Surface ; biosynthesis ; CHO Cells ; Cloning, Molecular ; Cricetinae ; DNA, Complementary ; biosynthesis ; genetics ; Eukaryotic Cells ; metabolism ; Genetic Vectors ; drug effects ; Humans ; Plasmids ; biosynthesis ; genetics ; Receptors, Tumor Necrosis Factor, Type I ; biosynthesis ; genetics ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; pharmacology ; Transfection

OBJECTIVEThis study was carried out to investigate the effects of insulin-like growth factor-II (IGF-II) and basic fibroblast growth factor (bFGF) on osteoprotegerin (OPG) secretion of periodontal ligament cells (PDLCs).

METHODSHealthy human premolars extracted for orthodontic reasons from 12-14 years old donators were obtained, and periodontal tissues were collected and cultured to obtain PDL cells. Primary or first passage PDLCs were cloned by means of limited dilutions. PDLCs with osteoblastic phenotypes were characterized as follows: Alkaline phosphatase activity, collagen III production and bone-like nodules formation. IGF-II and bFGF were added into culture media and their effects on PDLCs proliferation and OPG secretion were observed. The OPG concentrations in cell culture supernatants were detected by sandwich ELISA. Living cell numbers were demonstrated by MTT test. The average levels of OPG secretion by a single cell were calculated by dividing OPG concentration with MTT-test result.

RESULTSBoth IGF-II and bFGF upregulated the mtt values (P < 0.05), but ICF-II downregulated the opg/mtt values (P < 0.05), whereas bFGF had no significant effect on opg/mtt values (P > 0.05).

CONCLUSIONIGF-II enhances the proliferation of PDL cells but prohibits OPG secretion. Although bFGF has the same effect on the proliferation of PDL cells, it has no effect on OPG secretion. Before cytokines were used to enhance periodontal regeneration, their effects on local bone balance should also be studied.

Adolescent ; Cells, Cultured ; Child ; Fibroblast Growth Factor 2 ; pharmacology ; Glycoproteins ; biosynthesis ; Humans ; Insulin-Like Growth Factor II ; pharmacology ; Osteoprotegerin ; Periodontal Ligament ; cytology ; drug effects ; metabolism ; Receptors, Cytoplasmic and Nuclear ; biosynthesis ; Receptors, Tumor Necrosis Factor ; biosynthesis

OBJECTIVETo observe the effect of octreotide (OCT) on inhibiting hepatocellular carcinoma (HCC) and investigate its mechanisms.

METHODSNude mice bearing xenografts in situ were treated with OCT or saline control for 7 weeks since tumor implantation. The immunohistochemistry for somatostatin receptor 2 (SSTR2), cMet, transforming growth factor beta1 (TGFbeta1), phospho-Smad2, Smad4 and Smad7 was performed. SSTR2 and Smad4 mRNA expression was measured by semi-quantitative RT-PCR.

RESULTSAfter OCT treatment, the mean tumor weight in mice given OCT (0.17 +/- 0.14 g) was significantly lower than that of the control group (0.53 +/- 0.06 g). The inhibition rate of tumor was 67.9%. mRNA and protein expression of SSTR2, Smad4 in tumor cells of the treatment group were significantly more than that of the control group. cMet expression in OCT group was remarkably lower than that in control group. Between two groups, the expression of TGFbeta1, phospho-Smad2 and Smad7 were not remarkably different. In addition, phospho-Smad2 expression in HCC was significantly less than that of the normal hepatic cell.

CONCLUSIONOCT can inhibit the growth of HCC xenografts markedly. The mechanisms of OCT-induced inhibition effect may be related to up-regulating SSTR2 expression, down-regulating cMet, and recovering the function of TGFbeta/Smads-induced antitumor. In addition, the decreased expression of phospho-Smad2 may be an important feature of Bel7402 cells.

Animals ; Antineoplastic Agents, Hormonal ; therapeutic use ; Humans ; Liver Neoplasms, Experimental ; drug therapy ; metabolism ; pathology ; Mice ; Mice, Nude ; Neoplasm Transplantation ; Octreotide ; therapeutic use ; Proto-Oncogene Proteins c-met ; biosynthesis ; Receptors, Somatostatin ; biosynthesis ; Smad2 Protein ; biosynthesis ; Transforming Growth Factor beta ; biosynthesis

OBJECTIVETo explore the effect of Herba Epimedii flavone (HEF) on the osteoblast metabolism in vitro.

METHODOsteoblast were obtained from new born rat calvaria by digestive enzymes. MTF, PNPP and RT-PCR were used to observe the proliferation, activity of ALP and mRNA expression of OPG and RANKL of cultured osteoblasts in vitro.

RESULTIt was found that HEF had the effect on stimulating cell proliferation, activity of ALP and the mRNA expression of OPG of cultured osteoblasts (P < 0.01, P < 0.05).

CONCLUSIONHEF can promote the proliferation, the differentiation and the expression of OPG mRNA of the osteoblasts cultured in vitro.

Alkaline Phosphatase ; metabolism ; Animals ; Animals, Newborn ; Carrier Proteins ; biosynthesis ; genetics ; Cell Proliferation ; drug effects ; Cells, Cultured ; Epimedium ; chemistry ; Flavones ; isolation & purification ; pharmacology ; Glycoproteins ; biosynthesis ; genetics ; Membrane Glycoproteins ; biosynthesis ; genetics ; Osteoblasts ; cytology ; metabolism ; Osteoprotegerin ; Plants, Medicinal ; chemistry ; RANK Ligand ; RNA, Messenger ; biosynthesis ; genetics ; Rats ; Rats, Sprague-Dawley ; Receptors, Cytoplasmic and Nuclear ; biosynthesis ; genetics ; Receptors, Tumor Necrosis Factor ; biosynthesis ; genetics

To study the effects of free fatty acids on insulin secretion and expression of SUR1 gene in rat pancreatic B cells in vitro, and to explore the molecular mechanisms in lipotoxicity inducing insulin secretion dysfunction, pancreatic islet cells were isolated and digested from male SD rats. Purified islets were incubated with either 0.25 mmol/L palmitate or 0.125 mmol/L oleate for 48 h in vitro. Then islets were stimulated with either 5.6 mmol/L or 16.7 mmol/L glucose for 1 h. Insulin release was measured by using radioimmunoassay, and the expression of SUR1 gene mRNA was quantified by reserve transcription-polymerase chain reaction (RT-PCR). The islets exposed to both palmitate and oleate for 48 h showed an increased basal and a decreased glucose-indused insulin release as compared with control islets. Palmitate increased basal insulin secretion by 110% (P< 0.01), decreased glucose stimulated insulin secretion by 43% (P<0.01); while oleate increased basal insulin secretion by 80% (P<0.01) and decreased glucose stimulated insulin secretion by 32 % (P<0.05). RT-PCR showed that oleate significantly suppressed SUR1 gene expression by 64 % (P<0.01) as compared with the control group, while palmitate group manifested a light decrease of 15% (P>0.05) of SUR1 gene expression. Our results suggested that chronic exposure to free fatty acids of pancreatic beta cells inhibited glucose stimulated insulin secretion. Regulation of SUR1 gene expression may be involved in such effects, which may also be one of the molecular mechanisms in lipotoxocity inducing beta cells secretion dysfunction.
ATP-Binding Cassette Transporters ; biosynthesis ; genetics ; Animals ; Cells, Cultured ; Fatty Acids ; pharmacology ; Insulin ; secretion ; Islets of Langerhans ; drug effects ; physiology ; Male ; Potassium Channels ; biosynthesis ; genetics ; Potassium Channels, Inwardly Rectifying ; biosynthesis ; genetics ; RNA, Messenger ; biosynthesis ; genetics ; Rats ; Rats, Sprague-Dawley ; Receptors, Drug ; biosynthesis ; genetics ; Sulfonylurea Receptors

AIMTo examine the physiological role of the androgen receptor (AR) in the PC-3 cell line by transfecting full-length functional AR cDNA driven by its natural human AR promoter.

METHODSWe generated an AR-expressing PC-3(AR)9 stable clone that expresses AR under the control of the natural human AR promoter and compared its proliferation to that of the PC-3(AR)2 (stable clone that expresses AR under the control of the cytomegalovirus (CMV) promoter, established by Heisler et al.) after androgen treatment.

RESULTSWe found that dihydrotestosterone (DHT) from 0.001 nmol/L to 10 nmol/L induces cell cycle arrest or inhibits proliferation of PC-3(AR)2 compared with its vector control, PC-3(pIRES). In contrast, PC-3(AR)9 cell growth slightly increased or did not change when treated with physiological concentrations of 1 nmol/L DHT.

CONCLUSIONThese data suggest that intracellular control of AR expression levels through the natural AR promoter might be needed for determining AR function in androgen-independent prostate cancer (AIPC) PC-3 cells. Unlike previous publications that showed DHT mediated suppression of PC-3 growth after transfection of viral promoter-driven AR overexpression, we report here that DHT-mediated PC-3 proliferation is slightly induced or does not change compared with its baseline after reintroducing AR expression driven by its own natural promoter, as shown in PC-3(AR)9 prostate cancer cells.

Cell Cycle ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; DNA, Complementary ; biosynthesis ; Dihydrotestosterone ; pharmacology ; Humans ; Male ; Promoter Regions, Genetic ; Prostatic Neoplasms ; metabolism ; pathology ; Receptors, Androgen ; biosynthesis ; genetics ; Transfection

OBJECTIVETo investigate the influence of fluorosis on nicotinic acetylcholine receptors (nAChRs) in protein and gene levels in SH-SY5Y cells and the mechanism of the receptor modification.

METHODSSH-SY5Y cells, a human neuroblastoma cell line, were incubated with different concentrations of fluoride or with antioxidant for 48 hours. The functions of cells were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) method, and protein oxidation detected by carbonyl content; the alpha3 and alpha7 nAChR subunits in protein level were measured by Western blotting and in mRNA level by RT-polymerase chain reaction (RT-PCR).

RESULTSIn high-dose group as compared to the control, the decreased MTT (49%), increased protein oxidation (72%), and lower expression of alpha3 (51%) and alpha7 (47%) nAChR subunit proteins were obviously observed in SH-SY5Y cells. There were no changes in expression of nAChR subunit mRNAs between the cells treated with fluoride and those un-treated in controls. Prior treatment with antioxidant resulted in preventing the decrease of nAChR protein in cells exposed to the high doses of fluoride.

CONCLUSIONFluorosis should result in damage of cells and the declined expression of nAChRs in protein levels, but no influences on gene expression of the receptors in human neuroblastoma neurons. The decreased nAChR proteins might be involved in the mechanism of oxidative stress induced by fluorosis.

Cell Line, Tumor ; Fluoride Poisoning ; metabolism ; Fluorides ; toxicity ; Humans ; Neuroblastoma ; metabolism ; pathology ; Protein Processing, Post-Translational ; drug effects ; Proteins ; metabolism ; RNA, Messenger ; biosynthesis ; genetics ; Receptors, Nicotinic ; biosynthesis ; genetics

The stromal cell-derived factor 1 (SDF-1) interacts with its receptor CXCR4 to transduction signals, playing important roles in most physiological and pathological processes. It is reported that CXCR4 is highly expressed in many kinds of hematological malignancies and closely related to the prognosis, drug resistance and relapse of diseases. The growth of tumor cells can be inhibited by the anti-SDF-1 antibody or anti- CXCR4 antibody, supporting a new way for the therapy against hematological malignancies. Their expression in relation with prognosis and drug resistance of hematological malignancies are summarized in this review.
Chemokine CXCL12 ; biosynthesis ; genetics ; Drug Resistance, Neoplasm ; genetics ; Hematologic Neoplasms ; metabolism ; pathology ; Humans ; Prognosis ; Receptors, CXCR4 ; biosynthesis ; genetics ; Signal Transduction ; Stromal Cells ; metabolism