Apoptosis In Osteosarcoma MG-63 Cells Research Articles

Effects of matrix viscoelasticity on cell-matrix interaction, actin cytoskeleton organization, and apoptosis of osteosarcoma MG-63 cells.

Many recent reports have shown the effects of viscoelasticity of the extracellular matrix on the spreading, migration, proliferation, survival and cell-matrix interaction of mesenchymal stem cells and normal cells. However, the effect of matrix viscoelasticity on the behavior of tumor cells is still in the state of preliminary exploration. To this aim, we prepared a viscoelastic hydrogel matrix with a storage modulus of about 2 kPa and a loss modulus adjustable from 0 to 600 Pa, through adding linear alginate and regulating the compactness of a polyacrylamide covalent network. Overall, the addition of viscous components inhibited the apoptosis of osteosarcoma MG-63 cells, while it promoted their spreading and proliferation and in particular led to a well-developed cytoskeleton organization. However, with the increase of the viscous fraction, this trend was reversed, and the apoptosis of MG-63 cells gradually increased with gradually decreased spreading and proliferation, accompanied by a surprising manner change of the cytoskeleton from fusiform cells dominated by focal adhesion to dendritic cells dominated by pseudopodia. Besides the upregulation of MAPK, Ras, Rap1 and PI3K-Akt pathways commonly involved in mechanotransduction, the upregulation of the Wnt pathway and inhibited endoplasmic reticulum stress-mediated apoptosis were observed for the viscous matrix with a low loss modulus. The high viscosity matrix showed additional involvement of Hippo and NF-kappa B signaling pathways related to the cell-matrix interaction, with downregulation of the endoplasmic reticulum stress pathway and upregulation related to mitochondrial organization. Our study would provide insight into the effect of viscosity on fundamental behaviors of tumor cells and might have important implications in designing antitumor materials.

Calycosin induces apoptosis in osteosarcoma cell line via ERβ‑mediated PI3K/Akt signaling pathways.

Previous studies have shown that calycosin, a natural phytoestrogen which is structurally similar to estrogen, inhibits proliferation and induces apoptosis in estrogen-dependent cancer types via the estrogen receptor (ER)β-induced inhibition of PI3K/Akt. Therefore, the aims of the present study were to investigate the effects of calycosin on human osteosarcoma (OS), and to examine the molecular mechanisms associated with ERβ. Human OS MG-63 cells were treated with various concentrations of calycosin, and MTT and flow cytometry assays were used to assess the effects of calycosin on cellular proliferation and apoptosis. In addition, protein expression levels of ERβ, phosphorylated (p)-PI3K, p-Akt, cleaved poly (ADP-ribose) polymerase 1 (PARP) and cleaved caspase-3 were evaluated by western blot analysis. The present results suggested that calycosin inhibited proliferation and induced apoptosis in MG-63 cells. Furthermore, increased ERβ expression was detected in OS MG-63 cells treated with calycosin, and an ERβ inhibitor (PHTPP) reversed calycosin-induced cytotoxicity and apoptosis. Moreover, phosphorylation levels of PI3K and Akt were significantly downregulated after calycosin treatment, whereas PHTPP reversed their phosphorylation. ERβ-mediated PI3K/Akt downstream signaling pathways were found to influence the activity of poly (ADP-ribose) polymerase 1 and caspase-3. Thus, the present results indicated that calycosin inhibited proliferation and induced apoptosis in OS MG-63 cells, and that these effects were mediated by ERβ-dependent inhibition of the PI3K/Akt pathways.

LncRNA MEG3 inhibits proliferation and promotes apoptosis of osteosarcoma cells through regulating Notch signaling pathway.

To explore the effect of long non-coding ribonucleic acid (lncRNA)-maternally expressed gene 3 (MEG3) on the Notch signaling pathway, and its influences on the proliferation and apoptosis of osteosarcoma MG-63 cells. LncRNA MEG3 was overexpressed in osteosarcoma MG-63 cells, and the cells were divided into Blank group, Len-con group, and Len-MEG3 group. The expression level of MEG3 in each group was detected via quantitative Polymerase Chain Reaction (qPCR), the cell proliferation level in each group was detected via Cell Counting Kit-8 (CCK-8) assay, and the apoptosis in each group was detected via Hoechst 33258 staining. Moreover, the content of the inflammatory factors in each group was determined using the Enzyme-Linked Immunosorbent Assay (ELISA), and the expression levels of apoptosis-related proteins and Notch signaling pathway-related proteins were determined through Western blotting. The expression level of lncRNA MEG3 in Len-MEG3 group was significantly higher than that in the Blank group and Len-con group (p<0.01). The overexpression of lncRNA MEG3 could significantly weaken the proliferation (p<0.01) and enhance the apoptosis of osteosarcoma cells (p<0.01). The overexpression of lncRNA MEG3 could significantly increase the content of the inflammatory factor interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) (p<0.01), and remarkably decrease the content of the anti-inflammatory factor IL-10 in osteosarcoma cells (p<0.01). Besides, the overexpression of lncRNA MEG3 could evidently raise the expression of Caspase3 (p<0.01) and reduce the Bcl-2/Bax expression in osteosarcoma cells (p<0.01). Finally, the overexpression of lncRNA MEG3 could remarkably reduce the protein expressions of Jagged1, Notch1, and NICD1 in osteosarcoma cells (p<0.01). The overexpression of lncRNA MEG3 can inhibit the proliferation and promote the apoptosis of osteosarcoma MG-63 cells by suppressing the Notch signaling pathway.

Effects of rapamycin on osteosarcoma cell proliferation and apoptosis by inducing autophagy.

To investigate the influences of rapamycin on proliferation and apoptosis of human osteosarcoma MG-63 cells and the mechanisms of action. The human osteosarcoma MG-63 cells were randomly divided into Control group, Rapamycin group, and Rapamycin + Beclin-1 plasmid transfection group. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was adopted to detect the viability of MG-63 cells in each group, and the 5-Ethynyl-2'-deoxyuridine (EdU) staining and Hoechst staining were applied to determine the proliferation and apoptosis, respectively, of MG-63 cells in each group. The levels of B-cell lymphoma-2 (Bcl-2) and Bcl-2-associated X protein (Bax) were measured using enzyme-linked immunosorbent assay (ELISA) kits, and the protein expression levels of Beclin-1 and Vps34 in each group of MG-63 cells were tested using the Western blotting. Compared with the Control group, Rapamycin group, and Rapamycin + Beclin-1 plasmid transfection group had markedly weakened the viability of MG-63 cells, inhibited cell proliferation, remarkably increased cell apoptosis rate, elevated Bax level, notably declined Bcl-2 level, and significantly raised the levels of Beclin-1 and Vps34 proteins in MG-63 cells. Besides, the effects in Beclin-1 plasmid transfection group were stronger. Rapamycin may decrease the viability, inhibit the proliferation, and promote the apoptosis of MG-63 cells by activating autophagy.

Effect of plasma membrane-associated sialidase NEU3 activity on the proliferation and apoptosis of osteosarcoma MG-63 cells

Objective To investigate the effect of plasma membrane-associated sialidase 3 (NEU3) activity on the proliferation and apoptosis of osteosarcoma MG-63 cells in vitro. Methods MG-63 cells were cultured in vitro. Anti-NEU3 antibody (Ab) immunofluorescent staining was used to indicate the cellular localization of NEU3 in MG-63 cells. The cells treated with 0 nmol/L 2-deoxy-2, 3-didehydro-N-acetyl neuraminic acid (DANA) or 0 μg/ml anti-NEU3 Ab were used as blank control groups. The cells were treated with 10, 20, 50 nmol/L DANA, or 0.5, 1.0, 2.0 μg/ml anti-NEU3 Ab for 24 h or 48 h, respectively. The inhibition rates of the cell proliferation and cell apoptosis rates were measured with CCK-8 and flow cytometry. The expression levels of oncogene-related proteins, Ras protein and Bcl-2 protein, were detected by Western blotting. Results The immunofluorescence result showed that NEU3 was located in the cytoplasm of MG-63 cell. After treating with 0, 10, 20, 50 nmol/L DANA for 48 h, the inhibition rates of cell proliferation were 0, 15.10%±3.23%, 41.46%±2.31%, 64.68%±4.12%, with significant statistical difference (F=99.90, P 0.05). When the MG-63 cells were treated with 0, 10, 20, 50 nmol/L DANA for 24 h, the cell apoptosis rates were 4.05%±0.07%, 4.15%±0.23%, 12.85%±1.48%, 8.29%±0.86%, respectively, and the difference was statistically significant (F=23.21, P 0.05). When the MG-63 cells were treated with 0, 0.5, 1.0, 2.0 μg/ml anti-NEU3 Ab for 24 h, the cell apoptosis rates were 4.05%±0.07%, 20.13%±2.97%, 20.29%±2.82%, 20.58%±0.70%, with statistical significant difference (F=15.36, P=0.001). And the following contrast between each two groups showed that the differences between 0 μg/ml and each treated group were statistically significant (P 0.05). Western blotting results showed that the expression levels of Ras and Bcl-2 decreased with the increasing concentrations of DANA and anti-NEU3. Conclusion Inhibition of NEU3 enzyme activity can suppress the survival rate of MG63 cells and increase the cell apoptosis. The possible mechanism may be related to the declined expression of oncogene-related proteins Ras and Bcl-2, which suggests that NEU3 may be a possible target for treating osteosarcoma. Key words: Neuraminidase; Osteosarcoma; Cell proliferation; Apoptosis; MG-63 cells

Effect of attenuated expression of neuraminidase 3 via RNA interference on the proliferation and apoptosis of osteosarcoma MG-63 cells

To investigate the effect of attenuated expression of neuraminidase 3 (NEU3) via RNA interference on the proliferation and apoptosis in human osteosarcoma MG-63 cells. MG-63 cells were immunostained to observe the expression of NEU3. The cells were then divided into 5 groups: MG-63 cells in normal control group (group A) were not treated; MG-63 cells in 30, 50, and 100 nmol/L NEU3 RNA interference groups (groups B, C, and D) were transfected with 30, 50, and 100 nmol/L of NEU3 small interfering RNA (siRNA); negative control group (group E), MG-63 cells were transfected with different species negative siRNA (actin siRNA of mice, 50 nmol/L). The expression level of NEU3 mRNA was measured with real-time fluorescence quantitative PCR (qPCR). The proliferation of the cells was measured by cell counting kit 8 (CCK-8). The cell apoptosis rate was detected by flowcytometry (FCM). The expressions of cell apoptosis related proteins (Ras and Bcl-2) were detected by Western blot assay. NEU3 expressed in the cytoplasm of MG-63 cells under fluorescence microscope. The qPCR results showed that NEU3 mRNA levels were significantly lower in groups B, C, D than that in groups A and E ( P<0.05) after 24 hours of transfection; meanwhile, with the increase of siRNA concentration, NEU3 mRNA levels were significantly decreased ( P<0.05). The CCK-8 results showed that with the increase of siRNA concentration, the survival rate of MG-63 cells was significantly suppressed ( P<0.05) and the apoptosis rate of MG-63 cells was significantly accelerated ( P<0.05) after 48 hours of transfection. FCM results showed that after 24 hours of transfection, the number of live MG-63 cells decreased as that of the dead cells increased in groups B, C, D, and showing significant differences between 3 groups ( P<0.05). While the apoptosis rate in groups B, C, and D showed significant difference when compared with that of group A ( P<0.05); and when compared with group E, the apoptosis rate in groups C and D were significantly reduced ( P<0.05), but there was no significant difference between groups B and E ( P>0.05). The results of Western bolt assay showed that the protein levels of Ras and Bcl-2 in groups B and C were not significantly different from groups A and E ( P>0.05), while the protein levels of Ras and Bcl-2 were significantly decreased in group D ( P<0.05). Attenuated expression of NEU3 could inhibit the survival of MG-63 cells and accelerate its apoptosis. The results suggest that NEU3 could be a possible target for treating osteosarcoma.

JNK pathway mediates curcumin-induced apoptosis and autophagy in osteosarcoma MG63 cells.

Human osteosarcoma is a common primary malignancy of the bone in children and adolescents. It has been reported that curcumin is able to induce apoptosis in osteosarcoma MG63 cells through the mitochondrial pathway. However, whether curcumin is able to induce autophagy and the interaction between apoptosis and autophagy in osteosarcoma cells has yet to be fully elucidated. In the current study, it was determined that curcumin was able to significantly induce apoptosis, and lead to autophagy in MG63 cells. Notably, inhibition of apoptosis enhanced curcumin-induced autophagy due to upregulation of the c-Jun N-terminal kinase (JNK) signaling pathway. This finding was confirmed by the use of JNK-specific inhibitor, SP600125. Furthermore, our data showed that curcumin-induced apoptosis was increased when autophagy was completely inhibited by 3-methyladenine in MG63 cells. These results suggest that autophagy may have an important role in resistance to apoptosis when MG63 cells are incubated with curcumin. Thus, these results provide important insights into the interaction between apoptosis and autophagy in osteosarcoma cells and clinical treatment strategies using curcumin.

吴茱萸碱抑制Wnt/β-catenin信号通路诱导骨肉瘤MG-63细胞凋亡

Objective To investigate the effects and mechanism of evodiamine on the proliferation and apoptosis of osteosarcoma MG-63 cells. Methods MG-63 cells were cultured with evodiamine for 24 hours, and the cell proliferation was evaluated by methyl thiazolyl tetrazolium (MTT) assay. Cell cycle arrest, apoptosis and intracellular Ca2+ accumulation were evaluated by flow cytometry. BALB/C mice model of osteosarcoma was established to investigate the tumor inhibitory effect of evodiamine on human osteosarcoma. Wnt/β-catenin signaling protein expressions in osteosarcoma cells were detected by Western blotting. Results As concentration of evodiamine increasing (0.25 μmol/L, 0.5 μmol/L, 1.0 μmol/L, 2.0 μmol/L and 4.0 μmol/L), the inhibition rate of MG-63 cells increased [(4.18±1.26)%, (15.49±2.26)%, (40.55±6.57)%, (49.87±7.69)% and (60.42±8.29)%]. The difference was statistically significant between 2.0 μmol/L group and the control group (t=-2.66, P<0.05). MG-63 cells were cultured with 2.0 μmol/L evodiamine for 24 hours, and the apoptotic rate was (64.67±8.63)%, the proportion of S phase cells was (85.33±9.31)%, the fluorescence of Ca2+ was 97.33±21.31. The corresponding data of the control group were (4.94±0.81)%, (43.67±8.92)% and 28.67±8.92, the differences were statistically significant (t=-11.90, P<0.05; t=-7.22, P<0.05; t=-6.65, P<0.05). On mice model, the tumor weight of evodiamine group and the control group was (2.15±0.35)g and (4.29±0.49)g respectively, the difference was statistically significant (t=7.95, P<0.05). Comparing with the control group (1.00±0.00), evodiamine decreased the expression of β-catenin protein (0.72±0.36) and increased the expressions of Bax (1.15±0.27) and Caspase-3 (1.46±0.18) protein, and the differences were statistically significant (t=-3.05, P<0.05; t=-6.42, P<0.05; t=-5.85, P<0.05). Conclusion Evodiamine inhibits proliferation and induces apoptosis of human osteosarcoma MG-63 cells by blocking Wnt/β-catenin signaling. Key words: Evodiamine; Osteosarcoma; Cell proliferation; Apoptosis; Wnt/β-catenin

Triptolide induces the cell apoptosis of osteosarcoma cells through the TRAIL pathway

Research on triptolide, a diterpenoid epoxide found in the Thunder God Vine Tripterygium wilfordii, has increased our knowledge of the pharmacology, pharmacokinetics, toxicology and clinical application of this agent. In the present study, we aimed to identify the effects of triptolide on the apoptosis of osteosarcoma cells and to evaluate the anti-proliferative action of this agent. MG-63 cells were treated either with various doses of triptolide (50, 100 or 200nM) or DMSO for 6, 12and 24h. Treatment with triptolide effectively suppressed the cell viability and induced the apoptosis of osteosarcoma MG-63 cells as detected by MTT assay and flow cytometry, respectively. In addition, by using caspase-3, caspase-8 and caspase-9 activity assays and western blot analysis, the anticancer effects of triptolide against osteosarcoma growth were found to involve activation of the DR-5/p53/Bax/caspase-9/ caspase-3 signaling pathway and the DR-5/FADD/caspase-8/lysosomal/cathepsin B/caspase-3 signaling pathway in the MG-63 cells. An important factor in the anticancer effects of triptolide against osteosarcoma was TRAIL-DR-5. The data suggest that triptolide may be a potential novel chemotherapeutic agent for osteosarcoma and acts through the TRAIL-DR-5 signaling pathway.

Fucoidan Induces Cell Aggregation and Apoptosis in Osteosarcoma MG-63 Cells

ABSTRACTFucoidan, a sulfated polysaccharide found in brown algae, possesses various biological activities including anti-inflammatory and anti-cancer effects. In this study, we investigated the effects of fucoidan on the cell growth and morphology of human osteosarcoma MG-63 cells and found that fucoidan induces cell aggregation and apoptosis in osteosarcoma cells when the cells are treated with fucoidan upon seeding before becoming stably attached to the plates. Typical characteristics of apoptotic cells such as chromatin condensation and nuclear fragmentation were observed in fucoidan-treated cells. The number of annexin V-stained cells was increased by fucoidan treatment in a dose-dependent manner. Consistent with these results, cell viability and growth rate were decreased and cell spreading was inhibited in the presence of fucoidan, leading to rounded morphological changes of the cells. Our results demonstrate that fucoidan treatment results in cell aggregation through F-actin accumulation at the rounded cell cortex and apoptosis in osteosarcoma MG-63 cells.

Ursolic Acid Triggers Apoptosis in Human Osteosarcoma Cells via Caspase Activation and the ERK1/2 MAPK Pathway.

Ursolic acid (UA), a naturally occurring pentacyclic triterpene acid found in many medicinal herbs and edible plants, has been shown to trigger apoptosis in several lines of tumor cells in vitro. We found that treatment with UA suppressed the viability of human osteosarcoma MG-63 cells and induced cell cycle arrest at sub-G1 and G2/M phases. Furthermore, exposure to UA induced intracellular oxidative stress and collapse of mitochondrial membrane permeability, resulting in the subsequent activation of apoptotic caspases 8, 9, and 3 as well as PARP cleavage, and ultimately apoptosis in MG-63 cells. Moreover, protein analysis of mitogen-activated protein kinase (MAPK)-related protein expression showed an increase in activated ERK1/2, JNK, and p38 MAPK in UA-treated MG-63 cells. In addition, UA-induced apoptosis was significantly abolished in MG-63 cells that had been pretreated with inhibitors of caspase 3, 8, and 9 and ERK1/2. Furthermore, UA-treated MG-63 cells also exhibited an enhancement in Bax/Bcl-2 ratio, whereas anti-apoptotic XIAP and survivin were down-regulated. Taken together, we provide evidence demonstrating that UA mediates caspase-dependent and ERK1/2 MAPK-associated apoptosis in osteosarcoma MG-63 cells.

P14ARF enhances cisplatin-induced apoptosis in human osteosarcoma cells in p53-independent pathway

To study effect of tumor suppressor p14ARF on cisplatin-induced apoptosis in human osteosarcoma cells with its molecular mechanisms to provide evidences for increasing chemosensitivity of osteosarcoma. pcDNA3.1-p14ARF plasmid was stable transfected into MG63 cells lack of p14ARF expression. Expression of p14ARF on mRNA and protein level was evaluated with RT-PCR and Western blot. MG63, MG63-vec and MG63-ARF cells were treated with cisplatin. Cell growth inhibition and IC50 were determined through MTT assay. Apoptosis was detected using fluorescence-activated cell sorting and Hoechst33258 staining. The expression of p53, Bax, p21, Mdm2, Fas, Caspase-3, caspase-9 and PARP was detected with Western blot. RNAi was used to silence p53. Cells were pre-treated with Caspase-9 specific inhibitor Z-LEHD-FMK to determine whether the effect was Caspase-9-dependent. There was no expression of p14ARF in MG63 and MG63-vec cells but obvious expression in MG63-ARF cells on mRNA and protein level. Cell viability was 84.2%±4.3%, 80.8%±4.3% and 58.9%±5.4% in MG63, MG63-vec, and MG63-ARF cells after treatment of cisplatin for 72 h. IC50 was (11.1±0.6), (10.7±0.9) and (7.2±0.7) µmol/L. The apoptotic rate was 13.6%, 18.5% and 35.9% in groups, There were more obvious apoptotic more changes in MG63-ARF cells than MG63 and MG63-vec cells, and activation of Caspase-3, 9 and PARP on higher level in U2OS-ARF cells after stimulation with cisplatin for 72 h. The expression of p53, Bax, p21, Mdm2 and Fas, in MG63-vec and MG63-ARF cells did not changed (P>0.05). The expression of p53 was effectively and continuously suppressed by p53-siRNA in U2OS-vec and U2OS-ARF cells. The p53 silencing did not alter the cytotoxicity mediated by cisplatin treatment for 72 h (P>0.05). Cell viability was 96.8%±3.6%, 54.1%±5.7% and 89.5%±5.1% in Z-LEHD-FMK, cisplatin and Z-LEHD-FMK+cisplatin groups. p14ARF enhances cisplatin-induced apoptosis in human osteosarcoma MG63 cells in p53-independent caspase-9-dependent pathway, in which the intrinsic mitochondrial apoptotic pathway is involved.

Nanosecond pulsed electric field inhibits proliferation and induces apoptosis in human osteosarcoma

ObjectiveRecent studies suggest that nanosecond pulsed electric field (nsPEF) is a novel minimal invasive and non-thermal ablation method that can induce apoptosis in different solid tumors. But the efficacy of nsPEF on bone-related tumors or bone metastasis is kept unknown. The current study investigates antitumor effect of nsPEF on osteosarcoma MG-63 cells in vitro.MethodMG-63 cells were treated with nsPEF with different electric field strengths (0, 10, 20, 30, 40, and 50 kV/cm) and different pulse numbers (0, 6, 12, 18, 24, and 30 pulses). The inhibitory effect of nsPEF on the growth of MG-63 cells was measured by Cell Counting Kit-8 (CCK-8) assay at different time points (0, 3, 12, 24, and 48 h post nsPEF treatment). The apoptosis was analyzed by Hoechst stain, in situ terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL), and flow cytometric analysis. The expression of osteoprotegerin (OPG), receptor activator of NF-κB ligand (RANKL), and tumor necrosis factor α (TNF-α) was examined by reverse-transcription polymerase chain reaction (RT-PCR) and western blot.ResultsThe CCK-8 assay showed that nsPEF induced a distinct electric field strength- and pulse number-dependent reduction of cell proliferation. For treatment parameter optimizing, the condition 40 kV/cm and 30 pulses at 24 h post nsPEF achieved the most significant apoptotic induction rate. Hoechst, TUNEL, and flow cytometric analysis showed that the cell apoptosis was induced and cells were arrested in the G0/G1 phase. PCR and western blot analysis demonstrated that nsPEF up-regulated OPG expression had no effect on RANKL, increased OPG/RANKL ratio.ConclusionNsPEF inhibits osteosarcoma growth, induces apoptosis, and affects bone metabolism by up-regulating OPG, indicating nsPEF-induced apoptosis in osteosarcoma MG-63 cells. NsPEF has potential to treat osteosarcoma or bone metastasis. When nsPEF is applied on metastatic bone tumors, it might be beneficial by inducing osteoblastic differentiation without cancer proliferation. In the future, nsPEF might be one of the treatments of metastatic bone tumor.

Voltage-Gated Potassium Channel Kv1.3 Is Highly Expressed in Human Osteosarcoma and Promotes Osteosarcoma Growth

Deregulation of voltage-gated potassium channel subunit Kv1.3 has been reported in many tumors. Kv1.3 promotes tumorigenesis by enhancing cell proliferation while suppressing apoptosis. However, the expression and function of Kv1.3 in osteosarcoma are unknown. In the present study, we detected the expression of Kv1.3 in human osteosarcoma cells and tissues by RT-PCR, Western blot and immunohistochemistry. We further examined cell proliferation and apoptosis in osteosarcoma MG-63 cells and xenografts following knockdown of Kv1.3 by short hairpin RNA (shRNA). We found that Kv1.3 was upregulated in human osteosarcoma. Knockdown of Kv1.3 significantly suppressed cell proliferation and increased apoptosis as demonstrated by enhanced cleavage of poly (ADP-ribose) polymerase (PARP) and the activation of Caspase-3/7. Furthermore, adenovirus delivered shRNA targeting Kv1.3 significantly inhibited the growth of MG-63 xenografts. Taken together, our results suggest that Kv1.3 is a novel molecular target for osterosarcoma therapy.

Mechanism of apoptosis of human osteosarcoma M-G63 induced by arsenic trioxide

Objective To observe the apoptosis of osteosarcoma MG-63 cells induced by As2O3 and to explore its possible mechanisms. Methods The flowcytometric analysis and transmission electronmicroscope were performed to investigate the inducing apoptosis and inhibitative of As2O3 on osteosarcoma MG-63 cells. In order to study mechanism of apoptosis in MG-63 cells treated with As2O3, microarray was performed. The down-regulated gene was confirmed by RT-PCR, Northern-blotting. Results After treated with As2O3, hypodiploid peak before G0/G1 phase was observed in MG-63 cells through FCM analysis. Loss of microvilli, condensation and fragmentation of nuclear chromatin, condensation of cytoplasmic organelles, dilatation of the endoplasmic reticulum shrinkage of cells and alterations in cell membranes and apoptosis bodies which were observed in MG-63 cells treated with As2O3 by transmission electronmicroscope. The results of microarray show that As2O3 induced MG-63 cell apoptosis involves down-regulation of IEX-1 and the down-regulated gene is confirmed by RT-PCR and Northern-blotting. Conclusion The results show that As2O3 selectively inhibits growth of the solid tumor MG-63 cells by triggering apoptosis and indicates MG-63 induced by As2O3 cell apoptosis may through the IEX-1 pathway.