Kaempferol inhibits cell proliferation,invasion and migration via Wnt/β-catenin signaling in HBx-HepG2 cells

AIM: To explore the effects of kaempferol on the proliferation, invasion and migration abilities of HBx-HepG2 cells and to examine the underlying molecular mechanisms. METHODS: The expression levels of related genes at mRNA and protein levels were determined by RT-qPCR and Western blot. The cell apoptotic rate was analyzed by flow cytometry. The cell proliferation, growth, invasion and migration abilities were measured by MTT assay, colony formation assay, Transwell invasion assay and wound healing assay, respectively. RESULTS: Kaemferol inhibited HBx-HepG2 cell proliferation in a concentration-and time-dependent manner. Kaempferol at 100 μmol/L significantly inhibited the colony formation, invasion and migration abilities of the HBx-HepG2 cells. Kaemferol at 100 μmol/L also increased cell apoptotic rate, increased the protein levels of cleaved caspase-3, cleaved caspase-9 and Bax, and decreased the expression level of Bcl-2. In addition, kaemferol at 100 μmol/L suppressed the mRNA and protein expression levels of β-catenin, c-Myc and cyclin D1 in the HBx-HepG2 cells. Kaemferol at 100 μmol/L also suppressed the protein level of p-GSK-3β and the β-catenin protein levels in both cytoplasm and nucleus. LiCl treatment reversed the inhibitory effect of kaempferol on the growth, invasion and migration of the HBx-HepG2 cells. CONCLUSION: Kaempferol inhibits cell proliferation, invasion and migration via activating Wnt/β-catenin signaling in HBx-HepG2 cells.     

PPARγ mediates effects of diosgenin on proliferation and apoptosis in human glioblastoma U87MG cells

AIM:To investigate the effect of diosgenin (Dio) on the proliferation, apoptosis and expression of peroxisome proliferator-activated receptor γ (PPARγ) in human glioblastoma U87MG cells and its possible mechanism. METHODS:Human astrocytes (HA) and U87MG cells were cultured in vitro and treated with Dio (0, 10, 20, 30, 40 and 50 μmol/L) and GW9662 (5 μmol/L) for 48 h, and then the cell viability was detected by CCK-8 assay. Cell colony formation assay was used to assess the proliferation potential. Flow cytometry was used to analyze the cell cycle distribution and apoptosis. The mRNA expression level of PPARγ was measured by RT-PCR. Western blot was used to determine the protein levels of PPARγ, cyclin D1, cyclin E1, Bcl-2 and Bax. RESULTS:Dio had no significant influence on the viabi-lity of HA (P>0.05). However, Dio remarkably reduced the viability of U87MG cells in a dose-dependent manner (P<0.05) with IC₅₀ of 24.31 μmol/L. Meanwhile, Dio remarkably diminished colony formation ability (P<0.05), induced G₀/G₁ phase arrest of the cell cycle and apoptosis (P<0.05), up-regulated the expression of PPARγ at mRNA and protein levels, increased the protein level of Bax (P<0.05), and down-regulated the protein levels of cyclin D1, cyclin E1 and Bcl-2 (P<0.05) in a dose-dependent manner. However, these effects induced by Dio were inhibited by GW9662 (P<0.05), a specific inhibitor of PPARγ. CONCLUSION:Dio may inhibit proliferation and induce apoptosis in human glioblastoma U87MG cells most likely via up-regulating the expression of PPARγ, and then down-regulating the protein levels of cyclin D1, cyclin E1 and Bcl-2, and up-regulating the protein level of Bax.     

Effect of tanshinone IIA on expression of cell cycle regulators and proliferation of pancreatic cancer cells

AIM：To observe the effect of tanshinone IIA on the expression of cell cycle regulators and the proliferation of pancreatic cancer cell line BX-PC-3. METHODS： The pancreatic cancer cell line BX-PC-3 was treated with tanshinone ⅡA at various concentrations for 48 h. The inhibition of proliferation was measured by MTT method. The change of the cell cycle was detected by flow cytometry. The protein levels of cyclin A and cyclin D2 were determined by Western blotting. RESULTS：Tanshinoone IIA significantly inhibited the proliferation of BX-PC-3 cells in a dose-dependent manner. The cancer cells were arrested in stage G0/G1 after treated with tanshinone IIA at low dose. The protein levels of cyclin A and cyclin D2 were decreased after drug intervention. CONCLUSION：Tanshinone IIA inhibits the proliferation of human pancreatic cancer cell line BX-PC-3 and the expression of cell cycle-promoting factors (cyclin A and cyclin D2), which may be the mechanism of attenuating the proliferation of pancreatic cancer cells.     

Dominant negative human epidermal growth factor receptor induces G0/G1 arrest in human gastric cancer cells

AIM：To explore the effect of dominant negative epidermal growth factor receptor (DNEGFR) on the cell cycle of human gastric cancer cells. METHODS：Two human gastric cancer cell lines were used in the study. The cells were divided into 6 groups, including untreated SGC-7901 cells (US group), SGC-7901 cells stably transfected with pEGFP-N1 (ES group), SGC-7901 cells stably transfected with pEGFPN1-DNEGFR (DS group), untreated NCI-N87 cells (UN group), NCI-N87 cells stably transfected with pEGFP-N1 (EN group), and NCI-N87 cells stably transfected with pEGFPN1-DNEGFR (DN group). The cell cycle was determined by flow cytometry. The protein levels of cyclin-dependent kinase 2 (CDK2), cyclin D1, phosphorylated glycogen synthase kinase 3 beta at Ser9 ［p-GSK-3β (Ser9)］, p21 and p27 were detected by Western blotting. RESULTS：Transfection of the human gastric cancer cells with pEGFPN1-DNEGFR led to G0/G1 arrest, and down-regulated CDK2, cyclin D1, p-GSK-3β (Ser9) and up-regulated p21 and p27 as well. CONCLUSION：DNEGFR down-regulates cyclin D1 by activating GSK-3β, down-regulates CDK2, and up-regulates p21 and p27, which induce G0/G1 arrest in human gastric cancer cells in the end.     

Effect of sodium selenite on proliferation of endometrial cancer cells

AIM: To investigate the effect and mechanism of sodium selenite (Na₂SeO₃) on the proliferation of endometrial cancer cells. METHODS: Endometrial cancer Ishikawa cells and HEC-1A cells were treated with Na₂SeO₃. The effect of Na₂SeO₃ on cell proliferation was determined by MTT assay. The effects of Na₂SeO₃ on cell cycle distribution and apoptosis were tested by flow cytometric analysis. The expression of cyclin A was detected by Western blotting. RESULTS: Na₂SeO₃ inhibited the proliferation of Ishikawa cells and HEC-1A cells. For Ishikawa cells, IC₅₀ was 3.26 μmol/L, and for HEC-1A cells, IC₅₀ was 4.77 μmol/L. After treated with Na₂SeO₃, the cells in G₀/G₁ phase were reduced and the cells in S phase and G₂/M phase were increased. Na₂SeO₃ also increased the percentage of apoptosis cells. The result of Western blotting showed that the expression of cyclin A was increased. CONCLUSION: Na₂SeO₃ inhibits the proliferation of endometrial cancer Ishikawa cells and HEC-1A cells via up-regulating the expression of cyclin A, arresting cell cycle and inducing apoptosis.     

Sensitization of chemotherapy for human triple-negative breast cancer cells by methylseleninic acid

AIM:To observe the chemosensitization effect of methylseleninic acid (MSA) on human triple-negative breast cancer (TNBC) cells. METHODS:MDA-MB-231 cell line was co-cultured with MSA plus paclitaxel or doxorubicin. The inhibitory rate of cell proliferation was detected by CCK-8 assay. The combination index was calculated to explore the impact of MSA on the efficacy of chemotherapeutic drugs. The cell cycle was analyzed by flow cytometry. Annexin V-FITC/PI double staining was applied to detect the cell apoptosis. RESULTS:Compared with single usage of chemotherapeutic drugs, the cell proliferation rates were decreased when the chemotherapeutic drugs was combined with MSA, suggesting that there is a synergistic relationship between MSA and chemotherapeutic drugs. Compared with the single-agent groups, the G2/M-phase cells in paclitaxel combined with MSA group increased significantly (P<005),and the S-phase cells increased significantly in doxorubicin combined with MSA group (P<005). These suggested that MSA enhanced the anticancer effect of the drugs by inducing cell cycle arrest. Compared with single usage of 10 nmol/L paclitaxel, the apoptotic rate increased from 41.1% to 59.3% (P<005) as 10 nmol/L paclitaxel combined with 3.5 μmol/L MSA was used. Compared with single usage of 0.5 μmol/L doxorubicin, the apoptotic rate increased from 30.2% to 51.9% (P<0.01) as 0.5 μmol/L doxorubicin combined with 3.5 μmol/L MSA was used. These suggested that MSA enhanced antitumor effect of the drugs by inducing tumor cell apoptosis. CONCLUSION: MSA enhances the antitumor effects of chemotherapeutic drugs doxorubicin and paclitaxel on TNBC cells. One of the possible mechanisms is the enhancement of inducing tumor cell apoptosis and cell cycle arrest.     

Sinomenine inhibits viability,migration and invasion of human ovarian cancer SKOV3 cells

AIM:To investigate the effect of sinomenine on the viability, migration and invasion of human ovarian cancer SKOV3 cells and its possible mechanism. METHODS:The SKOV3 cells were treated with sinomenine at different concentrations for 12 h, 24 h and 48 h. CCK-8 assay was employed to detect the effects of sinomenine on the viability of the SKOV3 cells. Flow cytometry was used to analyze the cell cycle distribution. The cell migration and invasion abilities were measured by Transwell assay. Western blot was used to determine the protein levels of cyclin A, cyclin D1, E-cadherin and matrix metalloproteinase-9 (MMP-9). RESULTS:Sinomenine remarkably inhibited the viability of SKOV3 cells and IOSE80 cells in a time-dependent and dose-dependent manner (P<0.05), and the IC₅₀ values of 48 h were 2.12 mmol/L and 17.35 mmol/L, respectively. In a dose-dependent manner, sinomenine induced G₀/G₁ and S phase arrest in SKOV3 cells (P<0.05), suppressed the migration and invasion abilities of SKOV3 cells (P<0.05), down-regulated the protein levels of cyclin A, cyclin D1 and MMP-9 (P<0.05), and up-regulated the protein level of E-cadherin (P<0.05). CONCLUSION:Sinomenine inhibits the viability, migration and invasion of human ovarian cancer SKOV3 cells most likely via down-regulation of the protein levels of cyclin A, cyclin D1 and MMP-9, and up-regulation of the protein level of E-cadherin.     

4-Hydroxytamoxifen-stimulated activation of ezrin is mediated via G-protein-coupled receptor 30 and promotes human breast cancer MCF-7 cell migration

AIM：To investigate the effect of 4-hydroxytamoxifen (OHT) on the migration of human breast cancer cell line MCF-7. METHODS：The cell migration ability was assayed by scratch healing experiment. The protein expression of Src, p-Src, ezrin and p-ezrin were examined by Western blotting. RESULTS：The results of scratch healing experiment confirmed that both OHT and estradiol (E2) promoted MCF-7 cell migration and the E2-enhanced the cells migration was not inhibited by OHT. The most effective concentration of OHT that enhanced cell migration was 5 μmol/L. Significant promotion of the cell migration was observed at 6 h after OHT treatment. Increased p-ezrin and p-Src expression was observed after treatment with OHT and G-protein-coupled receptor 30 (GPR30) agonists G1. The expression of p-ezrin after OHT treatment was inhibited by G15 (GPR30 blocker) or PP2（Src inhibitor）. CONCLUSION：4-Hydroxytamoxifen promotes MCF-7 cell migration by activation of ezrin via GPR30 and c-Src.     

Effect of 3 isoforms of Ikaros on proliferation of human ovarian cancer SKOV3 cells

AIM: To investigate the effect of Ikaros isoforms on the proliferation of human ovarian cancer SKOV3 cells. METHODS: Three isoforms of Ikaros, IK1, IK2 and IK6, were transfected into ovarian cancer SKOV3 cells. CCK-8 assay and cell counting were used to detect the effects of Ikaros isoforms on the proliferation of SKOV3 cells. The cell cycle was analyzed by flow cytometry. The cell cycle-related proteins were detected by Western blot. RESULTS: IK1 and IK2 expression inhibited SKOV3 cells proliferation. Flow cytometry analysis indicated that IK1 and IK2 induced SKOV3 cell cycle arrest at the G₁ phase. IK6 isoform exerted no obvious effect on the proliferation or cell cycle of SKOV3 cells. Compared with control EV group, IK1 group and IK2 group showed a dramatic elevation in the expression of the cell cycle inhibitor p21, along with a substantial decrease in the expression of the cell cycle inducers cyclin D1 and cyclin D2, which did not change in IK6 group. CONCLUSION: IK1 and IK2 significantly inhibit the proliferation of ovarian cancer SKOV3 cells and induce cell cycle arrest at G₁ phase by regulation of cell cycle-related proteins cyclin D1, cyclin D2 and p21, while IK6 isoform exerts no obvious effect on the proliferation and cell cycle of SKOV3 cells.     

Effect of 7-hydroxyisoflavone on HCT116 cells proliferation by Id1

AIM:To investigated the effect of 7-hydroxyisoflavone (7-HIF) on the proliferation, apoptosis and stem-like cell feature of colorectal cancer cells. METHODS:The effect of 7-HIF on the proliferation of HCT116 cells was detected by WST-1 assay and colony formation assay. The effects of 7-HIF on the cell cycle distribution and apoptosis in the HCT116 cells were analyzed by flow cytometry. The expression of cell-cycle related proteins and the stemness related proteins was determined by Western blot. RESULTS:After treated with 7-HIF (200 μmol/L), the viability of HCT116 cells was inhibited, and the size and number of the colony were decreased as compared with control group (P<0.05). The G₀/G₁ phase of the cell cycle was increased. The proportion of S phase was decreased and the cells were mainly arrested in G₀/G₁ phase. The apoptotic rate of HCT116 cells was 21.4%, which was significantly higher than that in the control group (1.1%). The results of Western blot revealed that the expression of inhibitor of differentiation 1(Id1) was significantly decreased (P<0.05). The expression of cell cycle markers cyclin D1 and cyclin E, the proliferative markers survivin and PCNA, and stem cell markers CD133, ALCAM and EpCAM were all down-regulated by 7-HIF treatment (P<0.05). CONCLUSION:7-HIF inhibits the proliferation and induces the apoptosis of colorectal cancer cells, and inhibits the stem-like cell feature, which may be related to Id1 inhibition.     

Effects of IL-32γ on proliferation and cell cycle of rat vascular smooth muscle cells

AIM: To observe the effects of interleukin-32γ (IL-32γ)on the proliferation and cell cycle of rat vascular smooth muscle cells (VSMCs). METHODS: The VSMCs were isolated from the thoracic aorta of SD rats by the method of tissue-piece inoculation. The cells were cultured and treated with different concentrations of IL-32γ. The proliferation of the cells was examined by MTT assay. The cell cycles were analyzed by flow cytometry. The protein levels of NF-κB p65 and cyclin D1 were detected by Western blotting. The expression of proliferating cell nuclear antigen (PCNA)was examined by immunocytochemical staining. RESULTS: Administration of IL-32γ at the concentrations of 10~50 μg/L for 24~48 h significantly promoted the proliferation of VSMCs in a dose- and time-dependent manner. After stimulation with IL-32γ at the concentration of 50 μg/L for 24 h, the cell cycle transition from G₁ phase to S/G₂ phase was accelerated and the expression levels of NF-κB p65, cyclin D1 and PCNA increased as compared with those in control group. CONCLUSION: IL-32γ promotes the proliferation of rat VSMCs and accelerates the cell cycle transition via upregulating the expression of NF-κB p65 and cyclin D1.     

Effect of NF-κB inhibitor pyrrolidine dithiocarbamate on proliferation and apoptosis of human multiple myeloma U266 cells

AIM:To explore the effect of pyrrolidine dithiocarbamate (PDTC),an NF-κB inhibitor,on the proliferation and apoptosis of human multiple myeloma U266 cells and its mechanisms.METHODS:The U266 cells were treated with PDTC at different concentrations (0,25,50,100 and 200 μmol/L)in vitro.The growth inhibitory rate of the U266 cells was detected by CCK-8 assay and cell counting.The cell cycle of the U266 cells was determined by flow cyto-metry,and the apoptosis was examined by flow cytometry with Annexin V-FITC/PI staining.The effect of PDTC on the expression of DNA methyltransferase 1(DNMT1) at mRNA and protein levels was measured by RT-qPCR and Western blot,respectively.The effects of PDTC on the protein levels of NF-κB (P65),DNMT1,Bcl-2,cyclin D1,cleaved caspase-3 and cleaved caspase-8 were determined by Western blot.RESULTS:The protein level of NF-κB (P65) was decreased after treatment with PDTC for 48 h or 72 h.PDTC inhibited the proliferation of U266 cells in both dose-and time-dependent manners.After treatment with PDTC for 48 h,the percentage of U266 cells in G₂ phase increased compared with control group (P<0.05).PDTC induced the apoptosis of U266 cells in a dose-dependent manner.The expression of DNMT1 at mRNA and protein levels decreased (P<0.05).The results of Western blot showed that the expression of Bcl-2 in PDTC groups decreased,while the protein levels of cyclin D1,cleaved caspase-3 and cleaved caspase-8 were higher than those in control group (P<0.05).CONCLUSION:The NF-κB inhibitor PDTC inhibits the proliferation of U266 cells by inducing cell apoptosis.It may be related to the down-regulated expression of DNMT1,cell cycle arrest and activation of the apoptotic pathways.     

Effect of oridonin on invasion and migration of human lung cancer NCI-H460 cells

AIM：To investigate the effect of oridonin on the invasion and migration of human lung cancer NCI-H460 cells. METHODS：NCI-H460 cells were divided into high-dose (HD), middle-dose (MD) and low-dose (LD) oridonin groups (cultured with 40, 20 and 10 μmol/L of oridonin, respectively, as experimental groups), and normal (N) group (treated without oridonin as control). The cell growth was observed. The cell proliferation was detected by MTT assay. Boyden chamber was used to determine the cell invasive capacity. The cell migration was also measured. The levels of MMP-2 and MMP-9 were assayed by Western blotting. RESULTS：The cell counts in the experimental groups were lower than that in N group. The cell proliferation was inhibited as the inhibitory rates were 48.94%, 36.17% and 19.15% for HD group, MD group and LD group, respectively. The numbers of the invasive cells were 26.67±5.16 for HD group, 36.17±5.08 for MD group, and 44.33±5.50 for LD group. The migration rates in the experimental groups were lower than that in N group. The expression of MMP-2 and MMP-9 decreased dependent on the oridonin dose as follows: HD group < MD group < LD group < N group. CONCLUSION：Oridonin inhibits the invasion and migration of NCI-H460 lung cancer cells, and reduces the expression of MMP-2 and MMP-9.     

Apoptosis of the prostate cancer cell line PC-3M induced by E2F decoy DNA

AIM：To observe the effect of E2F decoy DNA on proliferation and apoptosis of androgen-independent prostate cancer cell line PC-3M.METHODS：E2F decoy DNA,ARE decoy DNA and control decoy DNA were transfected into PC-3M cells with lipofectamine,respectively.Their effects on cell proliferation were detected by MTT assay.The changes of cell morphology were observed by inverted phase contrast microscope.The cell apoptotic rate was determined by flow cytometry (FCM) analysis and chromosome DNA ladder was detected by DNA gel electrophoresis.The expression of c-Myc mRNA and cyclin D1 mRNA was detected by RT-PCR.The protein levels of c-Myc and cyclin D1 were detected by Western blotting.RESULTS：The growth of PC-3M cells was inhibited after transfection.The transfected PC-3M cells displayed typical apoptotic morphological changes.The apoptotic rate was 26.35% and DNA ladder was observed after transfection.The expression of c-Myc and cyclin D1 were inhibited.CONCLUSION：These results indicate that E2F decoy DNA induces apoptosis of androgen-independent prostate cancer cell lines PC-3M and inhibits cell proliferation via inhibiting expression of c-Myc and cyclin D1.     

Role of cyclin D1 in PKC regulating the proliferation of airway smooth muscle cells in asthmatic rat

AIM: To observe the expression of cyclin D1 following PKC activation and the correlation between PKC-α and cyclin D1 in asthmatic rat airway smooth muscle cells (ASMCs), and to discuss the effects of cyclin D1 on the proliferation of airway smooth muscle cells regulated by PKC in asthmatic rat. METHODS: Twelve SD rats were randomly divided into control group (group N) and asthmatic 2-week group (group A), and then subdivided into 4 groups based on the drug interventions: (1) control group; (2) PMA; (3) PMA+5 μmol/L Ro-31-8220 group; (4) 5 μmol/L Ro-31-8220 group. The proliferations of ASMCss were examined with cell cycle analysis, MTT colorimetric assay and proliferating cell nuclear antigen (PCNA) immunocytochemical staining. The expressions of PKC-α and cyclin D1 were analyzed by RT-PCR and Western blotting. The data were subject to correlation analysis. RESULTS: (1) Compared to group A1, there were significant differences in the percentage of S+G2/M phase, absorbance A value of MTT and the rate of positive expression of PCNA protein in group A2 and A4 (P<0.01). The same tendency in group N was observed according with group A. (2) Compared with A1, the ratios of A values of PKC-α mRNA and protein in group A2 and A4 were significantly changed (P<0.01) as well as the ratios of A values of cyclin D1 mRNA and protein. (3) There were positive correlations between PKC-α and cyclin D1 in mRNA (r=0.476, P<0.05) and protein(r=0.899, P<0.01). CONCLUSION: The activation of PKC-α promotes ASMCs proliferation in asthmatic rats, and there are positive correlations between the PKC-α and cyclin D1 in mRNA and protein, indicating that the PKC-α signal pathway may be involved in the process of airway smooth muscle remodeling by regulating the expression of cyclin D1 in asthmatic rats.     

Effects of PAR-2 agonist peptide on proliferation and cytosolic calcium level in hepatoma cells

AIM: To investigate the effects of PAR-2 agonist peptide on the proliferation and cytosolic calcium concentration (［Ca2+］c) in human hepatoma cells HepG2. METHODS: Human hepatoma cell line HepG2 was cultured. The cells were treated with PAR-2 agonist peptide SLIGKV-NH2 and the reverse PAR-2 agonist peptide VKGILS-NH2, respectively. The ［Ca2+］c of hepatoma cells were measured by microfluorimetric techniques based on calcium indicator fura-2/AM. The influences on proliferation of hepatoma cells were determined by MTT method. The changes of cell cycle were evaluated by flow cytometry, and the changes of cyclin D1 mRNA expression were detected by RT-PCR. RESULTS: After treated with 50 μmol/L SLIGKV-NH2, a rapid rise of ［Ca2+］c in HepG2 cells was induced (P<0.01), percent S phase, G2/M phase and proliferation index (PI) of HepG2 cells were elevated (P<0.01), and cyclin D1 mRNA expression was significantly upregulated (P<0.01). The proliferation rates of HepG2 cells treated with 1-50 μmol/L SLIGKV-NH2 were significantly increased, and the effect was in a dose-dependent manner (P<0.01 or P<0.05). No statistical significance of the difference between VKGILS-NH2 and control group was observed (P>0.05). CONCLUSION: PAR-2 agonist peptide induces the rise of ［Ca2+］c in HepG2 cells, upregulates the expression of cyclin D1 mRNA, accelerates the progress of cell cycle, promotes the synthesis of DNA and the proliferation of hepatoma cells via activating PAR-2 in vitro.     

Effect of bFGF on cyclin D1 and GADD153 expression in human ovarian cancer CAOV3 cells

AIM: To evaluate the effect of basic fibroblast growth factor (bFGF) on the expression of cyclin D1, growth arrest, DNA damage inducible gene 153 (GADD153), and its roles involved in cell cycle regulation and DNA repair in starvation-induced ovarian cancer CAOV3 cells apoptosis. METHODS: Apoptosis of ovarian cancer CAOV3 cells was induced by serum-free culture (starvation). After bFGF treatment, the cell proliferation rate, cell cycle and apoptosis were determined by MTT, FACS analysis and agarose electrophoresis, respectively. The expression of c-Fos, c-Jun and cyclin D1, GADD153 were detected by Western blotting. RESULTS: bFGF increased the cell proliferation and prevented starvation-induced cell apoptosis. In a time-dependent manner, bFGF induced the expression of c-Fos, c-Jun and cyclin D1 and inhibited GADD153. CONCLUSION: bFGF plays a critical role in anti-apoptosis and the proliferation in human ovarian cancer by upregulating the expression of c-Fos, c-Jun and cyclin D1 and inhibiting GADD153.     

Role of asiatic acid in treatment of insulin resistance in mouse adipocytes

AIM：To investigate the effects of asiatic acid, one of triterpenoids from Psidium guajava leaves, on the proliferation and differentiation of 3T3-L1 preadipocytes, and glucose and lipid metabolism of insulin-resistant adipocytes. METHODS：The proliferation of 3T3-L1 preadipocytes was tested by MTT assay, and the accumulation of lipid droplets in differentiated preadipocytes was measured by oil red O staining. The insulin-resistant cell model was established by exposure of the cells to dexamethasone. The cellular glucose uptake was determined by glucose oxidase-peroxidase assay. The free fat acid (FFA) concentration was detected by colorimetric method. Secreted adiponectin were measured by ELISA. The protein levels of peroxisome proliferator-activated receptor γ (PPARγ) and protein tyrosine phosphatase 1B (PTP1B) in insulin-resistant adipocytes were analyzed by Western blotting. RESULTS：Compared with medium group, asiatic acid increased the proliferation of 3T3-L1 preadipocytes and inhibited their differentiation at a concentration range of 10~100 μmol/L (P<0.05 or P<0.01). At concentrations of 30 μmol/L and 100 μmol/L, asiatic acid enhanced cellular glucose uptake in the insulin-resistant adipocytes both in basic and insulin-stimulation states. Asiatic acid decreased FFA production (P<0.05), and down-regulated the protein expression of PTP1B (P<0.05, or P<0.01). However, no effect on the secretion of adiponectin and the protein expression of PPARγ was observed (P>0.05). CONCLUSION：Asiatic acid enhances glucose uptake and inhibits FFA production in insulin-resistant adipocytes via down-regulating the protein expression of PTP1B, all of which play the roles of increasing insulin signaling sensitivity to improve insulin resistance.     

S100A6 promotes proliferation and migration of human osteosarcoma cell line 143B through PI3K/Akt signaling pathway

AIM: To investigate the effect of PI3K/Akt signaling pathway on S100A6-induced proliferation and migration of human osteosarcoma cell line 143B. METHODS: Recombinant human S100A6 protein (rhS100A6) was prepared. The 143B cells were treated with rhS100A6 in the presence or absence of PI3K inhibitor (LY294002 or wortmannin) exposure. The final concentrations of rhS100A6, LY294002 and wortmannin were 30 mg/L, 10 μmol/L and 0.5 μmol/L, respectively. The expression levels of total Akt (t-Akt) and phosphorylated Akt (p-Akt) in the 143B cells were analyzed by Western blotting. The cell proliferation and migration were determined by MTT and Transwell assays. RESULTS: rhS100A6 protein was successfully prepared, and significantly increased the proliferation and migration of 143B cells (P<005). rhS100A6 up-regulated the phosphorylation of Akt in 143B cells (P<005). Compared with rhS100A6 group, the level of p-Akt in 143B cells and the proliferation and migration of the cells were decreased in combined treatment group of rhS100A6 with LY294002 or wortmannin (P<005), where the proliferation rate at different time points dropped from 10.3% to 69.7% (P<005), and the migration rate dropped from 34.9% to 47.7% (P<005). CONCLUSION: To some extent, S100A6 promotes proliferation and migration of human ostersarcoma cell line 143B through PI3K/Akt signaling pathway.