Verapamil inhibits 3T3-L1 preadipocyte differentiation

Objective: To investigate the effect of the calcium channel blocker verapamil on adipocyte differentiation and its mechanism of action. Methods: Preadipocytes from 3T3-L1 strain mouse embryos were cultured and differentiated into matured adipocytes in vitro. Verapamil was added to the culture medium in the concentration of 30 μmol/L on Day 0. Cell differentiation was determined by Oil Red O staining and marker gene mRNA expression was evaluated and compared by RT-PCR. The fluo-3/AM probe and laser scanning confocal microscopy were used to measure intracellular calcium concentrations. Results: ①The differentiation rate of 3T3-L1 preadipocytes exposed to verapamil was lower than that of untreated cells. ②Verapamil promoted the retention of pref-1 gene expression. Lipoprotein lipase expression in the verapamil group was significantly lower than that in the control group on Day 4, Day 6 and Day 8 (P < 0.05) and resistin expression was significantly lower than that in the control group on Day 6, Day 8 and Day 10 (P < 0.05). Fatty acid synthase expression in the verapamil group was significantly lower than that in the control group from Day 2 (P < 0.05). ③ Intracellular concentrations of calcium [Ca2+]i in the verapamil group were significantly decreased compared with those in the control group on Day 2, Day 4 and Day 6 (P < 0.05), while there was no obvious difference between the two groups on Day 0 (P > 0.05). Conclusion: In 3T3-L1 preadipocytes verapamil significantly reduced adipocyte differentiation, down-regulated the mRNA expression of three marker genes for adipocytes differentiation, and prolonged the mRNA expression of an inhibitor of differentiation. The inhibitory effect of verapamil on differentiation may involve its role as a blocker of calcium influx in adipocytes.     

Blockage of PPAR8 increases the expression of-inflammatory factors in 3T3-L1 cells stimulated with TNFα

Objective： To investigate the role of peroxisome proliferator-activated receptors δ （PPARδ） in inflammatory reaction and its possible mechanism in adipocyte. Methods：Lentivirus-mediated RNA interference （RNAi） was used to block the expression of PPARδ in 3T3-L1 cells. In order to induce inflammation in 3T3-L1, cells were stimulated with tumor necrosis factor-α（TNFα, 20 ng/ml） for 4 h. The expression of PPARδ, nuclear factor κB （NFκB） and C reactive protein （CRP） were determined by Western blot analysis. Results：The expression of PPARδ was reduced by 80% after RNAi. Blockage of PPARδ promoted the expression of CRP and NFκB in cells stimulated with TNFα but had no effect on normal cells. Conclusion： PPARδ is involved in inflammatory reaction in adipocyte. Blockage of PPARδ can promote the inflammation mediated by inflammatory factors and increase the expression of NFκB and CRP in 3T3-L1 cells stimulated with TNFα.     

Effects of Rosiglitazone on Adiponectin Expression in 3T3- L1 Adipocytes at High Levels of Both Testosterone and Insulin In Vitro Culture

Objective To evaluate effects of rosiglitazone （RSG） on the expression of adiponectin in mature adipocytes at high levels of both testosterone （T） and insulin in vitro culture. Methods Mouse 3T3-L1 preadipocytes were induced to be mature adipocytes and used in this study. According to RSG concentrations, the cells added with T （10^-5 mol/L） and insulin （10^-4 mol/L） were divided into 4 groups： free-RSG group （0 mol/L RSG, FR-TI）, low-dose group （10^-9 mol/L RSG, LR-TI）, middle-dose group （lO-7mol/L RSG, MR-T1） and high-dose group （10^-6 mol/L RSG, HR-TI）. Besides, the cells added with RSG without T and insulin were also divided into 4 groups： FR, LR, MR, and HR. These 8 groups were incubated for 42 h. Cell viability was determined by MTT assay. Expression of adiponectin was detected by Western blotting. Results The maximum viability in FR-TI group was observed at point of 42 h. The growth of the adipocytes was significantly inhibited in MR-TI group compared with FR-TI （P〈0.01）. The level of adiponectin in MR-TI group was higher than that in LR- TI group （P〈0.01）. However, with RSG increasing; HR-TI group showed the lowest level of adiponectin among three treatment groups （P〈0.01）. In addition, adiponectin expression in MR-TI group was significantly higher than that in MR group （P〈0.01）. Conclusion RSG could increase the expression of adiponectin in 3T3-L1 adipocytes under high levels of both T and insulin, but it acts in a narrow concentration range.     

Blockage of PPARδ increases the expression of inflammatory factors in 3T3-L1 cells stimulated with TNFα

Objective: To investigate the role of peroxisome proliferator-activated receptors δ (PPARδ) in inflammatory reaction and its possible mechanism in adipocyte. Methods :Lentivirus-mediated RNA interference (RNAi) was used to block the expression of PPARS in 3T3-L1 cells. In order to induce inflammation in 3T3-L1, cells were stimulated with tumor necrosis factor-α(TNFα, 20 ng/ml) for 4 h. The expression of PPAR8, nuclear factor κB (NFκB) and C reactive protein (CRP) were determined by Western blot analysis. Results:The expression of PPARδ was reduced by 80% after RNAi. Blockage of PPARδ promoted the expression of CRP and NFκB in cells stimulated with TNFα, but had no effect on normal cells. Conclusion: PPARδ is involved in inflammatory reaction in adipocyte. Blockage of PPARδ can promote the inflammation mediated by inflammatory factors and increase the expression of NFκB and CRP in 3T3-L1 cells stimulated with TNFα.     

Effects of ghrelin on the proliferation and differentiation of 3T3-L1 preadipocytes

The effects of ghrelin on the proliferation and differentiation of 3T3-L1 preadipocytes and the possible mechanisms were investigated in this study. 3T3-L1 preadipocytes were cultured in vitro and treated with different concentrations of ghrelin. Proliferation of 3T3-L1 preadipocytes was evaluated by MTT method and mRNA levels of c-myc and thymidine kinase were detected by RT-PCR. Morphological changes of 3T3-L1 preadipocytes were observed and cell differentiation was measured by oil red O staining. The mRNA levels of peroxisome proliferator-activated receptor γ （PPARγ） and CAAT/enhancer binding protein （C/EBPa） in the cells at different differentiation stages were detected by RT-PCR. The results showed that ghrelin at concentrations of 10^-7 to 10^-15 mol/L could significantly promote preadipocyte proliferation （P〈0.05）, with the most pronounced effect observed at 10^-11 mol/L （P〈0.01）. Treatment of 3T3-L1 preadipocytes with ghrelin significantly increased the mRNA levels of c-myc and thymidine kinase （P〈0.01）. Morphological findings demonstrated that the great amount of lipid droplets appeared in the 3T3-L1 preadipocytes treated with ghrelin. Ghrelin could morphologically induce the differentiation of 3T3-L1 preadipocytes into mature adipocytes. Ghrelin significantly increased the mRNA levels of PPAR7 and C/EBPα during the differentiation, when compared with control group （P〈0.05）. The mRNA levels of PPARγ and C/EBPα were obviously up-regulated with the differentiation of preadipocytes after the treatment of ghrelin. There were significant difference in the mRNA levels of PPARγ and C/EBPu on day 2 and day 8 of the differentiation of 3T3-L1 preadipocytes （P〈0.01）. In conclusion, ghrelin could promote the proliferation and differentiation of 3T3-L1 preadipocytes by increasing the mRNA levels of PPARγ and C/EBPα and therefore enhance the sensitivity of adipocytes against insulin.     

Experimental Study on Inhibitory Effect of Niacinamide on Tumor Necrosis Factor-alpha-induced Matrix Degradation of Annulus Fibrous Tissue in vitro

The inhibitory effect of niacinamide on tumor necrosis factor-α （TNF-α） induced annulus fibrous （AF） degradation was assessed, and the mechanism of the inhibition was investigated. Chiba＇s intervertebral disc （IVD） culture model was established. Forty-eight IVDs from 12 adult Japanese white rabbits were randomly divided into 4 groups （12 IVDs in each group）, and various concentrations of niacinamide and TNF-α were added to the medium for intervention： negative control group, niacinamide control group （0.5 mg/mL niacinamide）, degeneration group （10 ng/mL TNF-α）, and treatment group （0.5 mg/mL niacinamide and 10 ng/mL TNF-α）. After one week＇s culture, AFs were collected for glycosaminoglycan （GS） content measurement, safranin O-fast green staining, and immunohistochemical staining for type Ⅰ , Ⅱ collagen and cysteine containing aspartate specific prote- ase-3 （Caspase-3）. It was found that the GS content in treatment group was increased by about 48% as compared with degeneration group （t=16.93, P〈0.001）, and close to that in niacinamide control group （t=0.71, P=0.667）. Safranine O-fast green staining exhibited higher staining density and better histological structure of AF in the treatment group as compared with the degeneration group. Immunohistochemical staining for both TypeⅠ and Ⅱ collagen demonstrated that lamellar structure and continuity of collagen in treatment group were better reserved than in degeneration group. Positive staining rate of Caspase-3 in AFs of negative control group, niacinamide control group, degeneration group and treatment group was 3.4%, 4.3%, 17.9% and 10.3% respectively. The positive rate in treatment group was significantly lower than in degeneration group （P〈0.01）. It was concluded that niacinamide could effectively alleviate TNF-α induced destruction and synthesis inhibition of matrix ingredients in AFs. The inhibition may be related with reduction of expression of Caspase-3. Thus, niacinamide is of potential f     

Effect of Tumor Necrosis Factor-α on Acyl Coenzyme A： Cholesteryl Acyltransferase Activity and ACAT1 Gene Expression in THP-1 Macrophages

In order to explore the effect and mechanisms of tumor necrosis factor-α (TNF-α) on the activity of the acyl coenzyme A: cholesteryl acyltransferase (ACAT), THP-1 monocytes were cul- tured and induced to differentiate into macrophages with phorbol ester. TNF-α (60 ng/mL) was added at different time points into the macrophage-containing medium and the ACAT enzyme activity was measured by quantifying the incorporation of 1-14C oleoyl CoA into cholesteryl esters. The expres- sion of ACAT-1 protein and mRNA was respectively detected by Western blotting and RT-PCR in THP-1 macrophages 24 h after treatment with TNF-α (60 ng/mL). The results indicated that ACAT activity in THP-1 macrophages treated with TNF-α was increased in a time-dependent manner. The expression levels of ACAT-1 protein and mRNA were significantly increased in THP-1 macrophages after treatment with TNF-α (P<0.05). It was suggested that TNF-α could increase the activity of ACAT in THP-1 macrophages by up-regulating the expression of ACAT-1 gene.     

Effects of fatty acid regulation on visfatin gene expression in adipocytes

Background The levels of long-term elevated serum or intracellular free fatty acid （FFA） induce insulin resistance associated with central obesity. The insulin-mimetic protein visfatin is preferentially produced by visceral adipose tissues and has been implicated in obesity and insulin resistance. To identify that FFA is capable of inducing insulin resistance and to clarify the role of FFA on visfatin, we examined the effect of monounsaturated FFA oleate （C 18： 1） and saturated FFA palmitate （C 16：0） on glucose transport and visfatin gene expression in cultured 3T3-L1 adipocytes or preadipocytes. Methods FFA-free DMEM/F12, 0.125 mmol/L, 0.5 mmol/1 and 1.0 mmol/L oleate or palmitate was added to cultured 3T3-L1 adipocytes or preadipocytes and incubated overnight. Glucose transport was assessed as 3H- 2-deoxy-glucose uptake. Total RNA was extracted and subjected to RT-PCR for the measurement of visfatin mRNA levels. Statistical comparisons between control group and other groups were performed with the two-tailed paired t test, and one-way ANOVA was used to compare the mean values among the groups. Results Insulin increased specific membrane glucose transport in 3T3-L1 preadipocytes. Upregulation was evident from 15 minutes to 1 hour exposure to insulin. However, after 6-hour exposure to insulin, there was a downregulation in the response to insulin. Dose response studies demonstrated that 2-deoxy glucose transport was increased by 336% at 50 nmol/L insulin （P〈0.01）, and reached a maximal effect at 100 nmol/L insulin （P〈0.01）. Oleate and palmitate treatment did not influence basal glucose transport （without insulin stimulation）, whereas insulin-stimulated glucose transport was inhibited after overnight oleate and palmitate treatment in preadipocytes and adipocytes. In 3T3-L1 preadipocytes, insulin resistance could be achieved at 0.125 mmol/L oleate or palmitate （P〈0.05, respectively）, and the inhibition was dose dependent. In adipocytes, the inhibition was noted at 0.5 mmol/L oleate or 1.0 mmol/L palmitate. Visfatin mRNA expression increased during differentiation more than 1.5-fold. Bovine serum albumin （BSA） did not influence visfatin mRNA expression compared with the control group. Dose-response studies demonstrated that addition of 0.125 mmol/L oleate and palmitate to 3T3-L1 adipocytes decreased visfatin mRNA expression significantly （78%, 77%, respectively, relative to untreated control, P〈0.05）, and further to 65% （relative to untreated control, P〈0.05） and 55% （relative to untreated control, P〈0.01） at 1.0 mmol/L FFA. Furthermore, the suppression on preadipocytes was similar to that of adipocytes, which reached a maximal reduction of 44% （oleate, P〈0.05） and 47% （palmitate, P〈0.05） at 1.0 mmol/L FFA. Conclusions Oleic acid and palmitic acid may induce insulin resistance in 3T3-L1 adipocytes and preadipocytes. Downregulation of visfatin mRNA may contribute to impair insulin sensitivity caused by oleate and palmitate.     

A resistin binding peptide selected by phage display inhibits 3T3-L1 preadipocyte differentiation

Background Resistin, a newly discovered cysteine-rich hormone secreted mainly by adipose tissues, has been proposed to form a biochemical link between obesity and type 2 diabetes. However, the resistin receptor has not yet been identified. This study aimed to identify resistin binding proteins/receptor. Methods Three cDNA fragments with the same 11 bp 5＇ sequence were found by screening a cDNA phage display library of rat multiple tissues. As the reading frames of the same 11 bp 5＇ sequence were interrupted by a TGA stop codon, plaque lift assay was consequently used to prove the readthrough phenomenon. The stop codon in the same 11 bp 5＇ sequence was replaced by tryptophan, and the binding activity of the coded peptide [AWIL, which was designated as resistin binding peptide （RBP）] with resistin was identified by the confocal microscopy technique and the affinity chromatography experiment, pDual GC-resistin and pDual GC-resistin binding peptide were co-transfected into 3T3-L1 cells to confirm the function of resistin binding peptide. Results Three cDNA fragments with the same 11 bp 5＇ sequence were found. The TGA stop codon in reading frames of the same 11 bp 5＇ sequence was proved to be readthroughed. The binding activity of RBP with resistin was consequently identified. The expression of the resistin binding peptide in 3T3-L1 preadipocytes expressing pDual G-C-resistin significantly inhibited the adipogenic differentiation. Conclusion RBP could effectively rescue the promoted differentiation of resistin overxepressed 3T3-L1 preadipocyte.     

A resistin binding peptide selected by phage display nhibits 3T3-L1 preadipocyte differentiation

Background Resistin, a newly discovered cysteine-rich hormone secreted mainly by adipose tissues, has been proposed to form a biochemical link between obesity and type 2 diabetes. However, the resistin receptor has not yet been identified. This study aimed to identify resistin binding proteins/receptor.Methods Three cDNA fragments with the same 11 bp 5’ sequence were found by screening a cDNA phage display library of rat multiple tissues. As the reading frames of the same 11 bp 5’ sequence were interrupted by a TGA stop codon, plaque lift assay was consequently used to prove the readthrough phenomenon. The stop codon in the same 11 bp 5’ sequence was replaced by tryptophan, and the binding activity of the coded peptide [AWIL, which was designated as resistin binding peptide (RBP)] with resistin was identified by the confocal microscopy technique and the affinity chromatography experiment. pDual GC-resistin and pDual GC-resistin binding peptide were co-transfected into 3T3-L1 cells to confirm the function of resistin binding peptide.Results Three cDNA fragments with the same 11 bp 5’ sequence were found. The TGA stop codon in reading frames of the same 11 bp 5’ sequence was proved to be readthroughed. The binding activity of RBP with resistin was consequently identified. The expression of the resistin binding peptide in 3T3-L1 preadipocytes expressing pDual GC-resistin significantly inhibited the adipogenic differentiation.Conclusion RBP could effectively rescue the promoted differentiation of resistin overxepressed 3T3-L1 preadipocyte.     

Effects of stromal-derived factor 1 preconditioning on apoptosis of rat bone mesenchymal stem cells

The effects of stromal-derived factor 1 preconditioning （PC） on apoptosis of bone mesenchymal stem cells （BMSCs） treated with hypoxia plus serum deprivation were investigated. Bone mesenchymal stem cells were cultured with the whole marrow-adherence technique. RT-PCR and immunohistochemistry were used to detect the expression of CXCR4. BMSCs were incubated in medium for 24 h with 10 ng/mL and 100 ng/mL SDF-1 respectively, and then they were treated with hypoxia plus serum deprivation for 6 h. Apoptosis rate was determined by flow cytometry and TUNEL method. The results showed that BMSCs had CXCR4 expression. The number of apoptotic cells was significantly reduced in SDF-1 PC group as compared with the control group, and 100 ng/mL SDF-1 PC group had the lowest level of apoptosis. It was concluded that SDF-1 preconditioning suppresses the apoptosis of BMSCs treated with hypoxia plus serum deprivation.     

Calorie control increased vaspin levels of serum and periepididymal adipose tissue in diet-induced obese rats in association with serum free fatty acid and tumor necrosis factor alpha

Background Vaspin was recently identified as a novel adipokine that is predominantly secreted from adipose tissue and exerts insulin-sensitizing effects. This study was undertaken to elucidate the regulative effects of calorie control on the expression of vaspin and its potential mechanism.Methods Diet-induced obese Sprague Dawley （SD） rats were adopted as experimental models and accepted interventions of various ingestions and pioglitazone. Various differentiated stages of cultured 3T3-L1 cells were dealt with pioglitazone or TNFα in vitro for 48 hours to further verify findings in animal experiments.Results The rats were successfully induced into an obese experimental model with hyperinsulinemia, hyperlipidemia, and increased serum free fatty acid and TNFa by 12-week high-fat diet. It was found that depending on whether the rats were fed by a high-fat diet or a basal diet, there was extremely higher vaspin in the periepididymal fat pad than in subcutaneous adipose tissues by 16 weeks. Vaspin in sera and the periepididymal fat pad was much lower in rats with a high-fat diet than those with a basal diet （all P 〈0.05）, but vaspin in subcutaneous fat tissues was prone to increase in rats with a high-fat diet. A 4-week calorie restriction or pioglitazone on the obese rats resulted in a partial recovery of vaspin levels in sera and periepididymal adipose tissues, especially the latter revealed a more obvious superiority and increased vaspin levels of subcutaneous adipose. Surprisingly, the treatment of 4-week high-fat diet on non-obese rats did not significantly depress vaspin of sera and periepididymal adipose tissues. However, it is unknown if re-feeding generated the effect on vaspin levels of obese and non-obese rats on sera or adipose tissues. The correlation analysis showed that vaspin levels of serum and periepididymal fat tissues were negatively correlated with serum FFA, TNFα and insulin; meanwhile, there was a positive correlation between serum vaspin and vaspin of periepididymal fat tissues. Pioglitazone enhanced vaspin levels in cultured 3T3-L1 cells and supernatant in various differentiated stages, and this effect became more and more obvious along with the change of preadipocytes into mature fat cells. Administration of TNFα caused suppression on vaspin expression in differentiated stages of 3T3-L1 cells.Conclusions The present data indicated that a long-term high-fat diet could induce obesity metabolic syndrome in SD rats and finally lead to lower vaspin of sera and periepididymal fat, while pioglitazone and chronic calorie-control ingestion could enhance the production of vaspin. It was undoubtedly demonstrated that vaspin expression was strongly associated with insulin sensitivity, serum FFA, and TNFα.     

The effect of celecoxib on tissue factor expression in pancreatic cancer cells

Background Tissue factor (TF) is overexpressed in many malignant tumours and is linked to the pathogenesis and prognosis of such malignancies. In vitro studies have proved that reduced expression of TF has inhibitory effect on the angiogenesis and cell proliferation of the malignant tumour. Therefore, TF suppression has been raised as a possible treatment for malignant tumours. Here we investigated the effect of celecoxib on TF expression induced by tumour necrosis factor α (TNFα) in PANC-1 cells and a possible molecular mechanism underlying the celecoxib effect.Methods Various doses of celecoxib solution were added to standard cell numbers of PANC-1 cells mixed with equal dose of TNFα for 6 hours. The expression of tissue factor was detected quantitatively by Western blot, whilst the activation of nuclear factor κB was tested by electromobility shift assay. Results As the doses of celecoxib increased, the tissue factor expression was decreased in PANC-1 cells and so was the activation of nuclear factor κB.Conclusions Celecoxib can downregulate the expression of tissue factor induced by TNFα in PANC-1 cells. This antitumour effect of celecoxib can be explained indirectly via its suppressive role in activation of nuclear factor κB.     

Ischemia-reperfusion injury up-regulates Pim-3 gene expression in myocardial tissue

This study examined the effect of ischemia-reperfusion injury on the expression of Pim-3 gene in myocardial tissues and their underlying mechanism.Rat models of myocardial ischemia-reperfusion injury were established by ligating the left anterior descending coronary artery of the rats.A total of 30 SD male adult rats were randomly divided into 5 groups:group A (sham operation,n=6);group B (in which the rats were subjected to 15 min of ischemia by ligation of the left anterior descending coronary artery,n=6);group C (in which the rats received 30 min of ischemia,n=6),group D and group E (in which the left anterior descending coronary artery of the rats were ligated for 30 min and then reperfused for 30 min or 120 min,n=6 in each).The left ventricular tissues were removed immediately after the ischemia-reperfusion injury.Neonatal cardiomyocytes were cultured and treated with different concentrations of H 2 O 2 (0,5,10,20 μmol/L) or tumor necrosis factor-α (TNF-α,0,1,5,10 ng/mL).The mRNA and protein expression of Pim-3 gene was determined by using RT-PCR,western blotting and immunohistochemistry.Additionally,neonatal cardiomyocytes were transfected with Pim-3 siRNA,and induced to develop apoptosis by using H 2 O 2.The results showed that normal myocardial tissues expressed a quantity of Pim-3 gene mRNA and protein.Ischemia-reperfusion injury could up-regulate the mRNA and protein expression of Pim-3 gene in myocardial tissues.Furthermore,H 2 O 2 but not TNF-α up-regulated the Pim-3 gene expression in cultured cardiomyocytes.And Pim-3 silencing failed to strengthen the H 2 O 2-inducing apoptosis in cardiomyocytes.It was concluded that ischemia-reperfusion injury up-regulated the Pim-3 gene expression through oxidative stress signaling pathway in myocardial tissues.     

Qushi Huayu Decoction (祛湿化瘀方) Inhibits Protein and Gene Expression of Cathepsin B in HepG2 Cells Induced by Free Fatty Acids

Objective: To study the experimental efficacy of Qushi Huayu Decoction (祛湿化瘀方,QHD) on protein and gene expression of cathepsin B (ctsb) in HepG2 cells induced by free fatty acids (FFAs).Methods: The model of HepG2 steatosis and tumor necrosis factor-α (TNF-α) secretion was induced by long-chain FFAs.HepG2 cells were divided into 4 groups: control group (group C),model group (group M),low-dose QHD group (group L) and high-dose QHD group (group H ).Long-chain FFAs were added to groups M,L and H.The 10% blank-control serum was added to group C and M,while 5% and 10% QHD-containing sera were added to group L and H,respectively.The levels of serum TNF-α and cellular triglyceride (TG) were detected.Cellular p-IκB and ctsb expression were detected using Western blot and PCR.The expression and distribution of ctsb were observed by immunofluorescence.Results: After incubating with FFA for 24 h,TG deposition in HepG2,TNF-α content in cell supernatant,the protein expression of cellular ctsb and P-IκB,as well as mRNA expression of ctsb increased markedly in group M compared with group C (P0.05,P0.01).Compared with group M,TG deposition,the expression of cellular ctsb,P-IκB and ctsb mRNA in groups L and H,as well as TNF-α content in group H,decreased significantly (P0.05).Cell immunochemical fluorescence studies showed that ctsb was released from lysosomes and distributed in the cytoplasm extensively and diffusedly after being stimulated with FFA.In this study,these above-mentioned changes were inhibited markedly in groups L and H.Conclusion: QHD might have a direct inhibitory effect on the ctsb target in the FFA-ctsb-TNFα pathway of hepatic lipotoxicity.     

Effects of transfection of ICAP-1α and its mutants on adhesion and migration of 2H-11 cells

This study examined the effect of integrin cytoplasmic domain-associated protein 1α (ICAP-1α) and its mutatants T38A and I138A on the adhesion, migration and tube formation of 2H-11 cells.rAAV-ICAP-1α, rAAV-T38A and rAAV-I138A were constructed.After infection, the expression of ICAP-1α and p-ERK1/2, p-c-Jun protein was measured by Western blotting.Adhesion ability was evaluated by using MTT.Cell migration was determined by using Boyden chamber method.Tube formation test was conducted on Matrigel.The results showed that in ICAP-1α, T38A and I138A groups, ICAP-1α protein expression was increased.In T38A and I138A groups, phospho-ERK1/2, phospho-c-Jun protein expressions were significantly increased as compared with the control group and the GFP group.ICAP-1α group protein expression was obviously decreased when compared with the control group and the GFP group.Cell adhesion ratio was 0.1429±0.0080 in control group, 0.1434±0.0077 in GFP group and the ratio in T38A and I138A groups increased to 0.3210±0.0082 and 0.3250±0.0079, respectively.In ICAP-1α group, the ratio was decreased to 0.1005±0.0073.In T38A and I138A groups, the number of migrating 2H-11 cells was increased to 31.45±3.20 and 33.10±5.40 against 18.51±2.80 in control group and 20.47±3.12 in GFP group.In ICAP-1α group, the number was decreased to 12.06±1.72.The number of tube-like structures was increased to 20.41±2.54 in T38A and to 22.26±3.07 in I138A groups as compared to those of control group 12.45±1.84 and GFP group 13.63±2.71.In ICAP-1α group, the number of tube-like structures was decreased to 8.32±1.24.It was suggested that rAAV-T38A and rAAV-I138A transfection can substantially increase 2H-11 cell adhesion, migration and angiogenisis, while rAAV-ICAP-1α can greatly inhibit the effect.These effects might be correlated with ERK1/2 and c-Jun protein phosphorylation.     

Inhibition of Invasion and Up-regulation of E-cadherin Expression in Human Malignant Melanoma Cell Line A375 by（-）-Epigallocatechin-3-gallate

The inhibitory effects of （-）-epigallocatechin-3-gallate （EGCG） on the invasion of human malignant melanoma cell line A375 and the possible molecular mechanisms of this effect were investiaged. A375 cells were pretreated with 20 μg/mL EGCG for 24, 48 and 72 h respectively and the E-cadherin expression was detected by Western blot analysis. A375 cells were also pretreated with different concentrations of EGCG （1, 5, 10 and 20 μg/mL） for 72 h and the expression of E-cadherin was measured by RT-PCR. The adhesion and invasion of A375 cells were tested by cell-matrigel adhesion assay and matrigel invasion assay respectively. The results showed that EGCG could significantly up-regulate the expression of E-cadherin time-and concentration-dependently （both P〈0.05）. Statistical analysis showed that A375 cells invasion was inhibited by EGCG and correlated with the up-regulation of E-cadherin expression. It was suggested that EGCG strongly inhibited invasion of A375 cells, and the inhibition mechanism was possibly associated with the up-regulation of E-cadherin expression.     

Hypoxia-Inducible Factor-lalpha Suppressing Apoptosis and Increasing Tolerance of Lung Cancer Cells to Chemotherapy

In order to construct plasmid of hypoxia-inducible factor-lalpha （HIF-1α）, and transfect into human lung cancer cells A549, the change in sensitivity of lung cancer cells A549 to chemotherapy was observed. HIF-1α mRNA structure region was amplified by RT-PCR and inserted into plasmid pcDNA3. The expression plasmid pcDNA3/HIF-1α was transfected into A549 with LipofectAMINE^TM2000. The expression of HIF-1α protein was detected by Western blot. After A549 cells were transfected with HIF-1α prior to addition of 5-Fu, the growth activity was measured by growth curve, apoptosis was detected by flow cytometry at 48 h, and the levels of caspase3 and MDR-1 were determined by Western blot. The results showed that the constructed expression plasmid was analyzed with restriction enzymes and gel electrophoresis. Two DNA lanes at 2.55 kb and 5.4 kb respectively were found, which were consistent with that expected. The growth rate in 5-Fu group was significantly inhibited, and the apoptosis index and caspase3 activity were increased significantly as compared with control group. After HIF-1α being transfected into A549, the activity of MDR-1 was increased and the effect of 5-Fu was weakened. In conclusion, HIF-1α can promote chemoresistance by increasing the activation of MDR1 and suppressing apoptosis during lung cancer cells A549 in- duced with 5-Fu.