Apoptosis In MG-63 Cells Research Articles

Triazine-modified dendrimer for efficient TRAIL gene therapy in osteosarcoma

Osteosarcoma is a high-grade malignant bone tumor that usually develops in the teenagers. Despite improvement in therapy, the five-year survival rate is poor for patients not responding to treatment or with metastases. Tumor necrosis factor (TNF) related apoptosis inducing ligand (TRAIL) gene therapy is a new strategy in the treatment of cancers, however, the lack of efficient and low toxic vectors remains the major obstacle in TRAIL gene therapy. In this study, a triazine-modified dendrimer G5-DAT66 was synthesized and used as a vector for TRAIL gene therapy in vitro and in vivo. The material shows much higher transfection efficacy on osteosarcoma MG-63 cell line than commercial transfection reagents such as Lipofectamine 2000 and SuperFect. It effectively induces apoptosis in MG-63 cells and three-dimensional MG-63 cell cultures when delivering a TRAIL plasmid. In vivo studies further prove that G5-DAT66 efficiently transfects TRAIL plasmid in tumors and inhibits tumor growth in osteosarcoma-bearing mice. These results suggest that triazine-modified dendrimer has promising potential for TRAIL gene therapy in osteosarcoma.

MicroRNA-377 suppresses the proliferation of human osteosarcoma MG-63 cells by targeting CDK6.

MicroRNAs (miRNAs) are essential to the progression of osteosarcoma. Previous research using osteosarcoma samples confirmed that miR-377 expression is less than that observed in normal human osteoblast expression. These data suggest a role for miR-377 in osteosarcoma that warrants investigation. To address this concept, we measured miR-377 expression in two cell models, and we also observed that miR-377 was less expressed in osteosarcoma MG-63 cells compared to the hFOB1.19 human fetal osteoblastic cell line. Moreover, miR-377 overexpression reduced cell proliferation and suppressed invasion of MG-63 cells but had no effect on MG-63 cell apoptosis. Because cyclin-dependent kinase 6 (CDK6) may be a potential target of miR-377 in osteosarcoma cells, we overexpressed CDK6 and observed that overexpression attenuated tumor suppressive effects of miR-377 on cell proliferation. Our data suggest that miR-377 can suppress proliferation in MG-63 cells in part by targeting CDK6.

Cadmium Induced Apoptosis in MG63 Cells by Increasing ROS, Activation of p38 MAPK and Inhibition of ERK 1/2 Pathways

Background/Aims: Cadmium (Cd) induces apoptosis in different kinds of cells, including osteoblasts, both in vivo and in vitro. However, little is known about the mechanisms by which Cd induces apoptosis. Methods: In the present study, we used the human osteosarcoma cell line MG63, which has characteristics similar to human osteoblasts, as an in vitro model to determine the cellular mechanisms by which Cd induces apoptosis. Results: We found that short-term exposure to CdCl2 induced apoptosis in MG63 cells. Furthermore, the incubation of cells with CdCl2 significantly increased the level of phosphorylated p38MAPK and significantly decreased the phosphorylation of ERK1/2 in a concentration-dependent manner. Additionally, the inhibition of the phosphorylation of p38 MAPK by SB202190 protected MG63 cells from Cd-induced apoptosis. The incubation of MG63 cells with the ERK1/2 inhibitor PD98059 significantly increased apoptosis in MG63 cells. CdCl2 also significantly increased the intracellular levels of ROS. N-acetylcysteine (NAC) significantly reduced ROS levels and reversed the effects of CdCl2 on MAPK signaling. Conclusion: Our results suggested that Cd induced apoptosis in MG63 cells by increasing ROS, activation of p38 MAPK and inhibition of ERK1/2 pathways.

Effect of radiation on cytotoxicity, apoptosis and cell cycle arrest of human osteosarcoma MG-63 induced by a ruthenium(II) complex

Radiation has large influence on the cytotoxicity, apoptosis and cell cycle arrest. The bioactivity of ruthenium(II) complex [Ru(dmb)2(DBHIP)](ClO4)2 (Ru1) (DBHIP=2-(3,5-dibromo-4-hydroxylphenyl)imidazo[4,5-f][1,10]phenanthroline) was investigated in the absence and presence of radiation. The cytotoxicity of Ru1 against MG-63 cells was evaluated by CCK-8 method. Ru1 shows high cytotoxicity upon radiation. Radiation can enhance the cytotoxicity of Ru1 on MG-63 cells. The apoptosis was studied by Hoechst 33258 staining method and flow cytometry. The reactive oxygen species, mitochondrial membrane potential, cell cycle arrest and western blot analysis were investigated in detail. The complex induces the apoptosis in MG-63 cells through ROS-mediated mitochondrial dysfunction pathway.

Berberine induces apoptosis and DNA damage in MG‑63 human osteosarcoma cells.

Berberine, an isoquinoline alkaloid extracted from the dry root of Coptidis Rhizoma, has been found to exhibit marked anticancer effects on a panel of established cancer cells. Among the human osteosarcoma lines treated, MG-63 cells were found to be the most sensitive. The present study investigated the potential genotoxic effect of berberine on MG-63 human osteosarcoma cells. The effect of berberine on cell viability was determined using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and cell apoptosis was analyzed by flow cytometry and a DNA ladder assay. γH2AX focus formation was used to detect DNA damage in MG-63 cells. Berberine induced a significant increase in apoptosis in MG-63 cells in a concentration- and time-dependent manner, as determined by DNA fragmentation analysis and flow cytometry. Furthermore, berberine induced significant concentration- and time-dependent increases in DNA damage compared with that in the negative control. In conclusion, these observations indicated that berberine induced apoptosis and DNA damage in MG-63 cells.

A chemically sulfated polysaccharide derived from Ganoderma lucidum induces mitochondrial-mediated apoptosis in human osteosarcoma MG63 cells.

To develop new anticancer agents, we prepared a sulfated polysaccharide (SCGLP1) from the fruiting bodies of Ganoderma lucidum, and the effect of SCGLP1 on human osteosarcoma MG63 cell line was investigated. Our result showed that treatment with SCGLP1 resulted in a significant inhibitory effect on cell proliferation and cell viability of MG63 cells in a dose- and time-dependent manner and caused apoptotic death in MG63 cells through an increase in G0/G1 phase arrest, but had minor cytotoxic effect on human normal osteoblast (NHOst) cells. Western blot analysis identified that SCGLP1-induced apoptosis was associated with an increased protein expression of proapoptotic Bax and Bad, decreased expression of antiapoptotic Bcl-2 and Bcl-XL, loss of mitochondrial membrane potential (Δψm), the release of mitochondrial cytochrome c to cytosol, and cleavage of caspase-9, caspase-3, and poly(ADP-ribose) polymerase (PARP). In addition, pretreatment with the pan-caspase inhibitor (z-VAD-fmk) blocked the SCGLP1-induced apoptosis in MG63 cells. The data indicate that SCGLP1-induced apoptosis is primarily associated with caspase-3- and caspase-9-dependent apoptotic pathway.

NLRP3 inflammasome is required for apoptosis of Aggregatibacter actinomycetemcomitans-infected human osteoblastic MG63 cells

Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) is a Gram-negative bacterium which is implicated in the pathogenesis of human periodontal disease and in particular aggressive periodontitis. Virulence factors from A. actinomycetemcomitans have been shown to induce apoptosis of osteoblasts, however, the underlying mechanisms of the induction of apoptosis are poorly understood. In the present study, the infection of A. actinomycetemcomitans in human osteoblastic MG63 cells was established. Accordingly, A. actinomycetemcomitans infection enhanced significant apoptosis of MG63 cells. We found that both expression levels of NLRP3 and ASC were increased dramatically after MG63 cell cultures exposed to A. actinomycetemcomitans. Moreover, the secretion of mature interleukin-1β (IL-1β) and IL-18 were extensively induced in A. actinomycetemcomitans-infected cells as compared with non-invasion group of MG63 cell cultures, indicating the activation of the NLRP3 inflammasome during infection. Finally, we found that the knockdown expression of NLRP3 by specific small interfering RNA (siRNA) attenuated apoptosis of A. actinomycetemcomitans-infected MG63 cells. Our data suggest that A. actinomycetemcomitans promotes apoptosis of human osteoblasts at least partially through the NLRP3 inflammasome.

Melittin protein inhibits the proliferation of MG63 cells by activating inositol-requiring protein-1α and X-box binding protein 1-mediated apoptosis

The aim of the present study was to explore the pro-apoptotic effect and specific mechanism of action of melittin (MEL) in humans. The effects of MEL on apoptosis in osteosarcoma and fetal osteoblast cells were investigated, and the mechanism that induced MG63 cell growth was also explored. The effects of MEL on cell proliferation were detected by a 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide analysis. Apoptosis was detected by flow cytometric analysis. MEL protein, inositol-requiring protein-1 (IRE-α), phosphorylated-protein kinase R-like endoplasmic reticulum (ER) kinase, spliced X-box-1 (XBP1), eukaryotic translation initiation factor-2α, cleaved activating transcription factor-6, caspase-12 and C/EBP homology protein (CHOP) were detected in three groups and two cell lines by western blot analysis. The results indicated that the expression or incubation of MEL in the MG63 cells triggered apoptosis and the inhibition of proliferation. One protein from the ER stress unfolded protein response pathway, IRE-α, was involved in the MEL-induced apoptosis in MG63 cells. Furthermore, spliced XBP1 protein was significantly increased in the MEL peptide incubated and MEL expressing groups of MG63 cells. Furthermore, CHOP protein expression was activated in MG63 cells following being incubated with or expressing MEL. In conclusion, MEL serves as an effective factor that inhibits the proliferation of MG63 cells via activating the ER stress-mediated apoptosis pathway. This activation is triggered by the IRE-α pathway mediated by inducing CHOP protein expression.

RETRACTED: miR-126 Functions as a Tumor Suppressor in Osteosarcoma by Targeting Sox2

Osteosarcoma (OS) is the most common malignant bone tumor in children and young adults, the early symptoms and signs of which are non-specific. The discovery of microRNAs (miRNAs) provides a new avenue for the early diagnosis and treatment of OS. miR-126 has been reported to be highly expressed in vascularized tissues, and is recently widely studied in cancers. Herein, we explored the expression and significance of miR-126 in OS. Using TaqMan RT-PCR analysis, we analyzed the expression of miR-126 in 32 paired OS tumor tissues and 4 OS cell lines and found that miR-126 was consistently under-expressed in OS tissues and cell lines compared with normal bone tissues and normal osteoblast cells (NHOst), respectively. As miR-126 is significantly decreased in OS tissues and cell lines, we sought to compensate for its loss through exogenous transfection into MG-63 cells with a miR-126 mimic. Ectopic expression of miR-126 inhibited cell proliferation, migration and invasion, and induced apoptosis of MG-63 cells. Moreover, bioinformatic prediction suggested that the sex-determining region Y-box 2 (Sox2) is a target gene of miR-126. Using mRNA and protein expression analysis, luciferase assays and rescue assays, we demonstrate that restored expression of Sox2 dampened miR-126-mediated suppression of tumor progression, which suggests the important role of miR-126/Sox2 interaction in tumor progression. Taken together, our data indicate that miR-126 functions as a tumor suppressor in OS, which exerts its activity by suppressing the expression of Sox2.

Induction of G2/M phase cell cycle arrest and apoptosis by ginsenoside Rf in human osteosarcoma MG-63 cells through the mitochondrial pathway

Ginsenosides, extracted from the traditional Chinese herb ginseng, are a series of novel natural anticancer products known for their favorable safety and efficacy profiles. The present study aimed to investigate the cytotoxicity of ginsenoside Rf to human osteosarcoma cells and to explore the anticancer molecular mechanisms of ginsenoside Rf. Five human osteosarcoma cell lines (MG-63, OS732, U-2OS, HOS and SAOS-2) were employed to investigate the cytotoxicity of ginsenoside Rf by MTT and colony forming assays. After treatment with ginsenoside Rf, MG-63 cells which were the most sensitive to ginsenoside Rf, were subjected to flow cytometry to detect cell cycle distribution and apoptosis, and nuclear morphological changes were visualized by Hoechst 33258 staining. Caspase-3, -8 and -9 activities were also evaluated. The expression of cell cycle markers including cyclin B1 and Cdk1 was detected by RT-PCR and western blotting. The expression of apoptotic genes Bcl-2 and Bax and the release of cytochrome c were also examined by western blotting. Change in the mitochondrial membrane potential was observed by JC-1 staining in situ. Our results demonstrated that the cytotoxicity of ginsenoside Rf to these human osteosarcoma cell lines was dose-dependent, and the MG-63 cells were the most sensitive to exposure to ginsenoside Rf. Additionally, ginsenoside Rf induced G2/M phase cell cycle arrest and apoptosis in MG-63 cells. Furthermore, we observed upregulation of Bax and downregulation of Bcl-2, Cdk1 and cyclin B1, the activation of caspase-3 and -9 and the release of cytochrome c in MG-63 cells following treatment with ginsenoside Rf. Our findings demonstrated that ginsenoside Rf induces G2/M phase cell cycle arrest and apoptosis in human osteosarcoma MG-63 cells through the mitochondrial pathway, suggesting that ginsenoside Rf, as an effective natural product, may have a therapeutic effect on human osteosarcoma.

Capsaicin induces apoptosis in MG63 human osteosarcoma cells via the caspase cascade and the antioxidant enzyme system

Osteosarcoma is the most common malignant bone tumor in children and adolescents. This aggressive cancer mostly occurs in the long bones. Therefore, novel therapeutic approaches, such as biological therapies and gene therapy, are required to efficiently treat osteosarcoma. Capsaicin (trans-8-methyl-N-vanillyl-6-nonenamide) has been demonstrated to inhibit the growth of several types of cancer cells and a number of studies have shown that osteosarcoma may be vulnerable to biological therapies. However, little is known regarding the therapeutic effects of capsaicin on osteosarcoma. This study investigated the effects of capsaicin on MG63 human osteosarcoma cells, in addition to elucidating the regulatory signaling pathways underlying the effects of capsaicin, the caspase cascade and the antioxidant enzyme system. The MG63 cell line was treated with various concentrations of capsaicin. Cells were analyzed using MTT and flow cytometry, and the presence of DNA fragmentation was evaluated using TUNEL assay. Results showed capsaicin induced apoptosis in MG63 cells. Thus, capsaicin exhibited an anticancer effect in osteosarcoma cells.

Activation of AMPK protects against hydrogen peroxide-induced osteoblast apoptosis through autophagy induction and NADPH maintenance: New implications for osteonecrosis treatment?

Elevated hydrogen peroxide (H2O2) causes osteoblast dysfunction and apoptosis, serving as an important contributor to the development of osteonecrosis. Here we aimed to understand the role of AMP-activated protein kinase (AMPK) in the process. We observed a high level of AMPK activation in surgery isolated patients' osteonecrosis tissues. In cultured osteoblastoma MG63 cells, H2O2 stimulation induced significant AMPK activation, oxidative stress, cell death and apoptosis. Inhibition of AMPK by its inhibitor (compound C) or by shRNA-mediated knockdown dramatically enhanced H2O2-induced MG63 cell apoptosis, while over-expression of AMPK in HEK-293 cells alleviated H2O2-induced cell damage. These results confirmed that H2O2-activated AMPK is pro-cell survival. We observed that H2O2 induced protective autophagy in MG63 cells, and AMPK-dependent Ulk1 activation and mTORC1 (mTOR complex 1) inactivation might involve autophagy activation. Further, AMPK activation inhibited H2O2-induced oxidative stress, probably through inhibiting NADPH (nicotinamide adenine dinucleotide phosphate) depletion, since more NADPH depletion and oxidative stress were induced by H2O2 in AMPK deficient MG63 cells. Finally, we observed a significant AMPK activation in H2O2-treated primary cultured and transformed (MC3T3-E1) osteoblasts, and AMPK inhibitor compound C enhanced death by H2O2 in these cells. Based on these results, we concluded that H2O2-induced AMPK activation is pro-survival and anti-apoptosis in osteoblasts. Autophagy induction and NADPH maintenance are involved in AMPK-mediated pro-survival effects. AMPK might represent a novel molecular target for osteonecrosis treatment.

A novel ruthenium(II) complex inhibits cell proliferation and induces apoptosis in MG-63 cells

Objective To investigate the effects of a novel ruthenium(Ⅱ) polypyridyl complex △-[Ru (phen)2MCMIP]2 + (△-1) on proliferation and apoptosis of human osteosarcoma cell line MG-63 in vitro.Methods Cell counting of kit-8 (CCK-8) assay was used to detect the proliferation of MG-63 cells after 24,48,72h treatment with △-1 under the concentrations of 0.00,12.50,25.00,50.00,100.00,150.00 μmol/L;Changes of apoptosis and cell cycle in MG-63 cells after 24 h treatment of 0.00,25.00,50.00,100.00 μmol/L A-1 were determined and analyzed by flow cytometry (FCM).Results Ruthenium (Ⅱ) polypyridyl complex A-1 could significantly inhibit the growth of MG-63 in a dose and time dependent manner; the IC50 of 24 h,48 h,72 h was 57.80μmol/L,45.27μmol/L,32.51μmol/L respectively; flow cytometry detection showed that A-1 induced 37.10％ of apoptosis,while only 1.06％ in control group,and arrested cell cycle at G0/G1 phase.Conclusion Ruthenium(Ⅱ) polypyridyl complex A-1 is able to inhibit proliferation and induce apoptosis in MG-63 cells and arrest cell cycle at G0/G1 phase. Key words: Ruthenium(Ⅱ) complex; MG-63 cells; Proliferation; Apoptosis; Cell cycle

Effect of Enterococcus faecalis Lipoteichoic Acid on Apoptosis in Human Osteoblast-like Cells

IntroductionEnterococcus faecalis is commonly detected in persistent apical periodontitis characterized by unimproved periradicular bone resorption. The aim of the present study was to examine the effect of lipoteichoic acid (LTA), a major virulence factor of E. faecalis, on apoptosis of osteoblasts. MethodsHuman osteoblast-like MG63 cells were treated with LTA from E. faecalis at a series of concentrations for 48 hours. The proliferation of the MG63 cells was assessed by 3-(4,5-dimethyl-thiazol-2-yl)-2,5- diphenyl-tetrazolium bromide assay. To examine the apoptosis, the LTA-treated cells were analyzed by flow cytometry by using annexin V–fluorescein isothiocyanate and propidium iodide double staining. Hoechst 33258 staining was performed to observe the morphologic changes of the cells. To investigate the apoptosis at the molecular level, the protein levels of Bcl-2 and Bax were determined by Western blot. Meanwhile, the caspase-3 activity was detected with caspase colorimetric protease assay. ResultsThe proliferation of MG63 cells was inhibited by E. faecalis LTA in a dose-dependent manner. Flow cytometry assay indicated that LTA had a stimulating effect on MG63 cell apoptosis. Typical morphologies of apoptotic cells were observed under fluorescence microscope. Furthermore, the cell apoptosis was confirmed by (1) the down-regulation of the antiapoptotic protein (Bcl-2), (2) the up-regulation of the proapoptotic protein (Bax), and (3) the elevated caspase-3 activity. ConclusionsLTA of E. faecalis could inhibit the proliferation and induce apoptosis of human osteoblast-like MG63 cells.

Knockdown of AXL receptor tyrosine kinase in osteosarcoma cells leads to decreased proliferation and increased apoptosis.

Dysregulation of the Axl receptor tyrosine kinase (RTK) has been implicated in the development and progression of a variety of malignancies. Axl is known to activate strong anti-apoptotic signaling pathways that promote oncogenesis. However, the role of Axl plays in osteosarcoma (OS) remains elusive. The present study aimed to investigate the clinical significance and function of Axl in human OS. Forty cases of OS and corresponding adjacent non-cancerous tissues (ANCT) were collected. The expression of Axl was assessed using immunohistochemical assay through tissue microarray procedure. A loss-of-function experiment was performed to investigate the effects of small hairpin RNA (shRNA)-mediated knockdown of Axl on the expression of p-AKT, poly ADP-ribose polymerase (PARP) and Ki-67, the proliferative activities, indicated by MTT assay, and the apoptotic index in OS MG-63 cells. As a result, the expression of Axl was found in OS tissues with higher strong reactivity rate, compared with the ANCT (75.0 percent vs 20.0 percent, P=0.000), but it did not associate with the age, gender, tumor size, TNM staging and distant metastases (each Pgreater than0.05). Furthermore, knockdown of Axl inhibited the proliferative activities and induced apoptosis in MG-63 cells with decreased expression of p-AKT, and Ki-67 and increased expression of PARP. In conclusion, our findings suggest that Axl is highly expressed in most of the OS tissues compared with the ANCT, and knockdown of Axl inhibits proliferation and induces apoptosis of OS cells possibly through downregulation of the AKT pathway, suggesting that our findings may provide new insights into the potential therapeutic target for cancer.

Ether à go-go 1 Silencing in Combination with TRAIL Overexpression Has Synergistic Antitumor Effects on Osteosarcoma

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been utilized for cancer therapy, but the resistance of cancer cells to TRAIL remains an obstacle. Ether à go-go 1 (Eag1) channel is overexpressed in a variety of cancers and implicated in tumor progression. However, the therapeutic potential of Eag1 in osteosarcoma remains elusive. In this study, we generated CRAd5.TRAIL/siEag1 adenoviral vector that permitted simultaneous knockdown of Eag1 and overexpression of TRAIL and investigated its antitumor effects on human osteosarcoma MG-63 cells. Our results showed that CRAd5.TRAIL/siEag1 induced growth arrest and apoptosis of MG-63 cells in a more efficient manner than CRAd5.TRAIL or CRAd5.siEag1, and had no effect on human osteoblastic hFOB 1.19 cells. Furthermore, treatment of an osteosarcoma xenograft model with CRAd5.TRAIL/siEag1 resulted in significant tumor regression and cancer cell apoptosis, compared with treatment with CRAd5.TRAIL or CRAd5.siEag1. Taken together, our results demonstrate that CRAd5.TRAIL/siEag1 may represent an effective strategy for osteosarcoma gene therapy due to the synergistic antitumor effects of Eag1 knockdown and TRAIL overexpression.

SASH1 regulates proliferation, apoptosis, and invasion of osteosarcoma cell

SASH1, a member of the SLY-family of signal adapter proteins, is a candidate tumor suppressor in breast and colon cancer. The SASH1 protein possesses both the SH3 and SAM domains, indicating that it may play an important role in intracellular signal transduction. Reduced expression of SASH1 is closely related to tumor growth, invasion, metastasis, and poor prognosis. However, the biological role of SASH1 remains unknown in osteosarcoma. To unravel the function of SASH1, we explored the expression of SASH1 in osteosarcoma tissues and its correlation to the clinical pathology of osteosarcoma and analyzed the relationship between SASH1 expression and cell cycle, apoptosis and invasion of osteosarcoma MG-63 cells, using the flow cytometry analysis and transwell invasion chamber experiments. Furthermore, the effect of SASH1 on the expression of cyclin D1, caspase-3, matrix metalloproteinase (MMP)-9 were observed by western blot. Our results showed that the expression rate of SASH1 mRNA in osteosarcoma tissues was significantly lower than that in normal bone tissue (p = 0.000), that the expression rate of SASH1 mRNA in the carcinoma tissues from patients with lung metastasis was significantly lower than that from patients without lung metastasis (p = 0.041), and that the expression rate of SASH1 mRNA also decreased with increasing Enneking stage (p = 0.032). However, the mRNA expression of SASH1 in osteosarcoma was independent of the patient's gender, age, and tumor size (p = 0.983, 0.343, 0.517, respectively). The SASH1 protein displayed a down-regulation in osteosarcoma tissues compared to normal bone tissue (p = 0.000), displayed a down-regulation in osteosarcoma tissues from patients with lung metastasis compared to from patients without lung metastasis (p = 0.000), and displayed a gradual decrease with increasing Enneking stage (p = 0.000). In addition, the MG-63 cells from pcDNA3.1-SASH1 group exhibited significantly reduced cell viability, proliferation, and invasive ability compared to the empty vector group and blank control group (p = 0.023, 0.001, respectively), and there was no difference between the empty vector group and blank control group. The pcDNA3.1-SASH1 group displayed significantly more apoptotic cells than the empty vector group and blank control group (p = 0.004). The expression of cyclin D1, MMP-9 displayed a down-regulation in MG-63 cells from pcDNA3.1-SASH1 group compared to the empty vector group and blank control group (p = 0.000, 0.001, respectively) and the expression levels of caspase-3 displayed an up-regulation in MG-63 cells from pcDNA3.1-SASH1 group compared to the empty vector group and blank control group (p = 0.000). Taken together, these data indicated that the overexpression of SASH1 might be associated with the inhibition of growth, proliferation, and invasion of MG-63 cells and the promotion of apoptosis of MG-63 cells.

Preparation and Antitumor Activity of a Polymeric Derivative of Methotrexate

A polymer-drug conjugate was developed by conjugating amino bonds of methotrexate (MTX) to succinoylated α,β-poly[(2-hydroxyethyl)-L-aspartamide] (PHEA). The therapeutic efficacy of PHEA-MTX was evaluated in vitro and in vivo. PHEA-MTX showed sustained release properties when incubated in pH 5.5 and pH 7.4 buffering solutions at 37°C. PHEA-MTX induced MG63 cell apoptosis in a time-dependent and concentration-dependent manner in vitro and inhibited the growth of S180 sarcoma in vivo. PHEA-MTX was more potent and, more importantly, displayed less systemic toxicity than free MTX. The enhanced therapeutic effects of PHEA-MTX suggest that the PHEA-MTX conjugate may have a greater potential for chemotherapy of cancers.

Antitumor Activity of Histone Deacetylase Inhibitor Trichostatin A in Osteosarcoma Cells

Histone deacetylase (HDAC) inhibitors have been reported to induce cell growth arrest, apoptosis and differentiation of tumor cells. The present study aimed to examine the effects of trichostatin A (TSA), one such inhibitor, on the cell cycle, apoptosis and invasiveness of osteosarcoma cells. MG- 63 cells were treated with TSA at various concentrations. Then, cell growth and apoptosis were determined by 3-(4, 5-dimethyl-2-thiazolyl)-2H-tetrazolium bromide (MTT) and TUNEL assays, respectively; cell cycling was assessed by flow cytometry; invasion assays were performed with the transwell Boyden Chamber system. MTT assays revealed that TSA significantly inhibited the growth of MG-63 cells in a concentration and time dependent manner. TSA treated cells demonstrated morphological changes indicative of apoptosis and TUNEL assays revealed increased apoptosis of MG-63 cells after TSA treatment. Flow cytometry showed that TSA arrested the cell cycle in G1/G2 phase and annexin V positive apoptotic cells increased markedly. In addition, the invasiveness of MG-63 cells was inhibited by TSA in a concentration dependent manner. Our findings demonstrate that TSA inhibits the proliferation, induces apoptosis and inhibits invasiveness of osteosarcoma cells in vitro. HDAC inhibitors may thus have promise to become new therapeutic agents against osteosarcoma.

Apoptosis induced by sonodynamic therapy in human osteosarcoma cells in vitro.

The aim of the present study was to investigate the potential effect of hematoporphyrin monomethyl ether-sonodynamic therapy (HMME-SDT) on MG-63 osteosarcoma cells. The HMME concentration was kept constant at 20 µg/ml and the MG-63 osteosarcoma cell line was exposed to ultrasound with an intensity of 1.0 W/cm2 for 30 sec. Cell cytotoxicity was quantified using an MTT assay 6 h after HMME-SDT. The intracellular localization of HMME was imaged using inverted confocal laser scanning microscopy. Apoptosis was investigated using flow cytometry with Annexin V-fluorescein isothiocyanate and propidium iodine staining. The cytotoxicity of HMME-mediated sonodynamic action on MG-63 cells was significantly higher than that of other treatments, including ultrasound alone, HMME alone and sham treatment. Flow cytometry demonstrated that HMME‑SDT action markedly enhanced the apoptotic rate of MG-63 cells. The mechanisms of apoptosis were analyzed by measuring the protein expression of poly ADP-ribose polymerase (PARP), cleaved PARP, procaspase-3, cleaved caspase-3 and cleaved caspase-9. The data demonstrated that HMME-SDT action markedly induced the apoptosis of MG-63 cells.