Objective: To observe whether there is evidence for vascular channel formation by osteosarcoma cellsin vitro and to illustrate mechanism of vasculogenic mimicry in osteosarcoma.Methods: Osteosarcoma cell lines (U-2OS)...Objective: To observe whether there is evidence for vascular channel formation by osteosarcoma cellsin vitro and to illustrate mechanism of vasculogenic mimicry in osteosarcoma.Methods: Osteosarcoma cell lines (U-2OS) were tested for their ability to form tubular networks in three-dimensional culture containing type I collagen. The structures of the tubular networks were observed under a phase contrast microscope and an electron microscope.Results: Observation under light microscopy and electron microscopy showed that high aggressive osteosarcoma cells line (U-2OS) formed networks containing channels when grown in three-dimensional culture containing type I collagen in the absence of endothelial cells or fibroblasts.Conclusion: These observations strongly suggest that aggressive osteosarcoma cells may generate vascular channels that facilitate tumor perfusion independent of tumor angiogenesis and have the ability of vasculogenic mimicry. Key words osteosarcoma cells line - vasculogenesis mimicry - angiogenesis - 3-dimensional cultures This study was supported in part by the National Natural Sciences Foundation of China (No. 30271314).展开更多
Objective: To find out a method of extraction and purification of bone morphogenetic protein (BMP) from osteosarcoma cell conditioned medium, and evaluate the biological activity of BMP.Methods: Conditioned medium of ...Objective: To find out a method of extraction and purification of bone morphogenetic protein (BMP) from osteosarcoma cell conditioned medium, and evaluate the biological activity of BMP.Methods: Conditioned medium of osteosarcoma cell lines (MG-63) was collected, concentrated and dialyzed. The concentrated protein was purified through gel chromatography on Sephcryl-S-100. The purified protein was tested by BMP monoclonal antibody (McAb), its molecular weight (MW) was determined by SDS-PAGE and its biological activity was demonstrated by heterotopic ossification.Results: The purified protein was proved to be BMP by BMP McAb, had a satisfactory heterotopic ossification, and its MW was about 21 kD.Conclusion: BMP existed in the conditioned medium of osteosarcoma cell and had a satisfactory biological activity after purification. Because osteosarcoma cell can be cultured and grew for a long timein vitro, this method will be helpful to a vast extraction of BMP and clinical application. Key words osteosarcoma cell - conditioned medium - bone morphogenetic protein - protein purification This project was a key scientific and technological program of Hubei Provicial Scientific and Technological Committee (No. 002p1503).展开更多
Objective: This study investigated the effects of rh-TRAIL with or without chemotherapeutic drugs on the apoptosis of the osteosarcoma cell line, MG-63, and the influence of chemotherapeutic drugs on changes in the e...Objective: This study investigated the effects of rh-TRAIL with or without chemotherapeutic drugs on the apoptosis of the osteosarcoma cell line, MG-63, and the influence of chemotherapeutic drugs on changes in the expression of DR5 and YinYang 1 (YY1) in MG- 63 cells. Methods: The effects of treatment with rh-TRAIL alone and/or chemotherapetic drugs on MG-63 cell growth inhibition and apoptosis were measured using the MTT assay, FACS analysis ofAunexin V labeled cells, and the mRNA changes of DR5 and YY1 were detected by RT-PCR. Results: Rh-TRAIL protein inhibited the growth of MG-63 cells, and this inhibition was increased by adriamycin and IFN-γ. Adriamycin and IFN-γ significantly facilitated the induction of the expression of DR5 and reduced the expression of YY1. Conclusion: The apoptosis-inducing effect of rh-TRAIL in MG-63 cells was enhanced by chemotherapeutic drugs.展开更多
This study is to examine the effect of human recombinant soluble TRAIL (TNF-related apoptosis-inducing ligand) protein inducing apoptosis in MG-63 human osteosarcoma cells. The inhibitive rates of TRAIL to MG-63 cel...This study is to examine the effect of human recombinant soluble TRAIL (TNF-related apoptosis-inducing ligand) protein inducing apoptosis in MG-63 human osteosarcoma cells. The inhibitive rates of TRAIL to MG-63 cells were detected by MTT assay. The apoptosis induced by TRAIL in MG-63 human osteosarcoma cells was analyzed with FACS and TUNEL and the apoptotic bodies were observed by transmission electron microscope. MTT assay showed that the inhibitive rates of 500, 1 000, 2 000 and 4 000 ng/mL TRAIL for 24 h were 10.1%, 24.3%, 50.6% and 97.7% respectively. Flow cytometric analysis showed that after MG-63 cells were treated with 2 gg/mL TRAIL for 6 h, obvious apoptotic peak would immediately appear before diploid peak. Human soluble TRAIL protein can quickly kill MG-63 osteosarcoma cells selectively, and may have potential value for clinical treatment of osteosarcoma.展开更多
Objective: To investigate the inhibitory effects of LMWH suppressing the expression of Livin and inducing the apoptosis of the osteosarcoma cells. Methods: Osteosarcoma cells line MG-63 was cultured in vitro. MTT assa...Objective: To investigate the inhibitory effects of LMWH suppressing the expression of Livin and inducing the apoptosis of the osteosarcoma cells. Methods: Osteosarcoma cells line MG-63 was cultured in vitro. MTT assay and flow cytometry were used to study the effect of LMWH with different concentration suppressed the prolifetation and induced apop- tosis in osteosarcoma cells line MG-63. The expression of Livin of osteosarcoma cells line MG-63 was analysed by the im- munohistochemistrical method and PT-PCR. Results: Low molecular weight heparin could inhibit the growth of osteosarcoma cell line MG-63. With the LMWH's increasing, the apoptosis rate was increased significantly. Immunohistochemistrical method and PT-PCR showed that the expression of Livin of osteosarcoma cells line MG-63 declined obviously than that before medi- cation. Conclusion: LMWH has very strong anti-tumor effect in vitro. The possible mechanisms of LMWH anti-tumor effect are associate with the effect of suppressing the expression of Livin and inducing cell apoptosis.展开更多
Objective To characterize and compare the different biological behaviors of two novel human osteosarcoma cell lines,Zos and Zos-M,established respectively from the primary site and the skip metastasis of an osteosarco...Objective To characterize and compare the different biological behaviors of two novel human osteosarcoma cell lines,Zos and Zos-M,established respectively from the primary site and the skip metastasis of an osteosarcoma patient.Methods Two展开更多
AIM:To investigate the effect of prednisolone,a synthetic glucocorticoid used in inflammatory diseases,on the growth of cultured osteosarcoma cells.METHODS:Two osteosarcoma cell lines with different degree of differen...AIM:To investigate the effect of prednisolone,a synthetic glucocorticoid used in inflammatory diseases,on the growth of cultured osteosarcoma cells.METHODS:Two osteosarcoma cell lines with different degree of differentiation were used.SaOS2 show a rather mature phenotype,while U2 OS are negative for almost all osteoblastic markers.The cells were exposed to different concentrations of prednisolone(1-9 μmol/L) with or without antioxidants or the inhibitor of inducible nitric oxide synthase(i NOS) l-N6-(iminoethyl)-lysine-HCl(L-NIL).Cell growth was assessed by counting viable cells.The production of nitric oxide(NO) was measured in the conditioned media by the Griess method.The production of reactive oxygen species was quantified using 2'-7'-dichlorofluorescein diacetate.Western blot with specific antibodies against NOSs was performed on cell extracts.RESULTS:Prednisolone inhibited SaOS2 cell growth in a dose dependent manner.No significant effects were observed in U2OS.The inhibition of SaOS2 growth is not due to oxidative stress,because antioxidants do not rescue cell proliferation.Since high concentrations of NO inhibit bone formation,we also measured NO and found it induced in SaOS2,but not in U2 OS,exposed to prednisolone,because of the upregulation of i NOS as detected by western blot.Therefore,we treated SaOS2 with prednisolone in the presence or in the absence of L-NIL.L-NIL prevented NO release induced by prednisolone at all the concentrations apart from 9 μmol/L.At the same concentrations,we found that L-NIL rescued SaOS2 growth after exposure to prednisolone.In U2 OS cells,prednisolone did not induce NO production nor affected cell growth.All together,these data indicate that a link exists between increased amounts of NO and growth inhibition in response to prednisolone in SaOS2.CONCLUSION:Prednisolone inhibited SaOS2 proliferation by increasing the release of NO through the upregulation of i NOS,while no effect was exerted on U2OS.展开更多
The effect of forskolin, an activator of adenylate cyclase, on glucocorticoid-induced modulation of proliferation and differentiation of a human osteosarcoma cell line(HOS-8603) was iniually studied. It was found that...The effect of forskolin, an activator of adenylate cyclase, on glucocorticoid-induced modulation of proliferation and differentiation of a human osteosarcoma cell line(HOS-8603) was iniually studied. It was found that forskolin could significantly augment展开更多
Objective: This study investigated the effect of NS398 on anti-proliferation and the mechanism of inducing apoptosis of human osteosarcoma cell MG-63 line in vitro. Methods: Growth suppression was detected by MTT me...Objective: This study investigated the effect of NS398 on anti-proliferation and the mechanism of inducing apoptosis of human osteosarcoma cell MG-63 line in vitro. Methods: Growth suppression was detected by MTT method. Special morphological changes of apoptosis were observed by transmission electron microscopy (TEM) and DNA fragments electrophoresis. The apoptotic rates were quantified by flow cytometry (FCM). And Bcl-2 protein level were detected by Western Blotting assay. Results: Different concentration NS398 inhibited the cell growth. Through TEM and DNA electrophoresis, the special morphological changes were observed after 24, 48 and 72 h treatment with NS398. The apoptotic rates of MG-63 cells treated with NS398 were respectively, significantly higher than that of the control group( P 〈0.01 ). Western blot assay showed that NS398 reduced Bcl-2 protein expression. Conclusion: NS398 suppressed the proliferation of human osteosarcoma cell MG-63 line and induced apoptosis. The mechanism may be associated with down-regulation expression level of bcl-2 protein.展开更多
The outcome of patients with osteosarcoma has not significantly improved in the last three decades. Therefore, there is still a need for the development of more effective therapeutic strategies. Methoxyamine (MX) is a...The outcome of patients with osteosarcoma has not significantly improved in the last three decades. Therefore, there is still a need for the development of more effective therapeutic strategies. Methoxyamine (MX) is a base excision repair (BER) inhibitor that has shown anticancer potential by sensitizing a variety of tumor cells to ionizing radiation and chemotherapeutic drugs. In the present study, the in vitro antiproliferative effects of MX were evaluated in two osteosarcoma cell lines, HOS and MG-63. Evaluation of the influence on radiosensitivity and drug interactions in simultaneous treatments with methotrexate, doxorubicin, and cisplatin was also performed. Exposure to MX significantly decreased cell proliferation and mediated a substantial increase of apoptosis. Moreover, our results showed that MX synergized with ionizing radiation in both cell lines while potentiated the antitumor effects of cisplatin and methotrexate. Altogether, the results presented herein demonstrate the feasibility of inhibiting the BER pathway, which may in future be a promising strategy for overcoming intrinsic tumor resistance and to improve the outcome of patients with osteosarcoma.展开更多
The apoptosis of osteosarcoma cells treated with irradiation by 153Sm-EDTMP was studied. The morphological changes in osteosarcoma cells were observed by fluorescence microscopy. It was found that osteosarcoma cells e...The apoptosis of osteosarcoma cells treated with irradiation by 153Sm-EDTMP was studied. The morphological changes in osteosarcoma cells were observed by fluorescence microscopy. It was found that osteosarcoma cells exposed with 153Sm-EDTMP displayed significant nuclear fragmentation and marked pyknosis. With the prolongation of observing period, the membrane bound apoptotic bodies formation was observed. It should be noted, that with the lengthening of irradiation time by 153Sm-EDTMP, the inhibition rate of proliferation of osteosarcoma cells increased progressively.展开更多
Background P-glycoprotein (P-gp) encoded by ATP-binding cassette sub-family B member 1 (ABCB1) gene is a kind of ATP-dependent drug transporter, which plays important roles in multidrug resistance (MDR) of human...Background P-glycoprotein (P-gp) encoded by ATP-binding cassette sub-family B member 1 (ABCB1) gene is a kind of ATP-dependent drug transporter, which plays important roles in multidrug resistance (MDR) of human cancers, such as osteosarcoma. Curcumin is a natural phenolic coloring compound originating from the rhizomes of Curcuma Ionga, which is proved to possess antitumor biological activities including reversion of MDR. However, the effect and molecular mechanisms of curcumin to osteosarcoma MDR remain unclear.展开更多
Previously,it has been found that glucocorticoid receptor(GR)binding activity decreasedrapidly during heat shock response in HOS-8603,a human osteosarcorna cell line.In this study,Therelationship between the induction...Previously,it has been found that glucocorticoid receptor(GR)binding activity decreasedrapidly during heat shock response in HOS-8603,a human osteosarcorna cell line.In this study,Therelationship between the induction of heat shock proteins(HSPs)and the decrease in GR was furtherstudied in the same cell line.It was found that even though quercetin could specifically inhibit the ex-pression of hsp90α and hsp70 mRNA,it could not prevent GR from the decrease in response to the heatshock treatment.This represents the first reported evidence that the induction of HSPs and the decrease inGR during heat shock response were 2 independent biological events.The results of the present study furthershowed that although the heat shock treatment alone had no effects on alkaline phosphatase(AKP)activity,itcould completely block the induction of AKP activity in HOS-8603 cells by dexamethasone(Dex),a syntheticglucocorticoid.These results demonstrate that the heat shock-induced alteration in GR was accompanied by adecrease in GR functional activity.Furthermore,when the induction of HSPs was inhibited by the treatmentof cells with quercetin,the stimulatory effects of Dex on AKP activity could still be inhibited completely bythe heat shock treatment.The results of this part,on the basis of GR functional activity,further demonstratethat quercetin could not inhibit the heat shock-induced decrease in GR,even though it could inhibit the induc-tion of HSPs.To clarify further the effects of quercetin alone on GR binding activity in HOS-8603 cells,theregulation of GR by quercetin was also studied.It was found for the first time that quercetin coulddown-regulate GR in a time-dependent manner significantly,and that the down-regulation of GR by quercetinin HOS-8603 cells paralelled with a decrease in glucocorticoid-mediated functional responses,suggesting thatthe down-regulation of GR by quercetin is of biological significance.展开更多
Osteosarcoma is the most common primary malignant bone cancer in children and adolescents.Emerging evidence has suggested that the capability of a tumor to grow is driven by a small subset of cells within a tumor,term...Osteosarcoma is the most common primary malignant bone cancer in children and adolescents.Emerging evidence has suggested that the capability of a tumor to grow is driven by a small subset of cells within a tumor,termed cancer stem cells(CSCs).Although several methods have been explored to identify or enrich CSCs in osteosarcoma,these methods sometimes seem impractical,and chemotherapy enrichment for CSCs in osteosarcoma is rarely investigated.In the present study,we found that short exposure to chemotherapy could change the morphology of osteosarcoma cells and increase sarcosphere formation in vitro,as well as increase tumor formation in vivo.Furthermore,methotrexate(MTX)-resistant U2OS/MTX300 osteosarcoma cells were larger in size and grew much more tightly than parental U2OS cells.More importantly,U2OS/MTX300 cells possessed a higher potential to generate sarcospheres in serum-free conditions compared to parental U2OS cells.Also,U2OS/MTX300 cells exhibited the side population(SP)phenotype and expressed CSC surface markers CD117 and Stro-1.Notably,U2OS/MTX300 cells showed a substantially higher tumorigenicity in nude mice relative to U2OS cells.Therefore,we conclude that chemotherapy enrichment is a feasible and practical way to enrich osteosarcoma stem cells.展开更多
Background Osteosarcoma (OS) is the most common primary malignant tumor of bone. Mouse models of human OS can invariably provide greater insight into the complex mechanisms that underlie the development and pathogen...Background Osteosarcoma (OS) is the most common primary malignant tumor of bone. Mouse models of human OS can invariably provide greater insight into the complex mechanisms that underlie the development and pathogenesis of this aggressive tumor. Bioluminescence technology favored tracing cancer cells in vivo. In this study, an OS model was described and evaluated using human OS cell line, Saos2, labeled with luciferase (Saos2-1uc). Methods Saos2 cells were infected by lentivirus loading a firefly luciferase gene. Luciferase expression of Saos2-1uc cells was characterized both in vitro and in vivo. Specific biologic and oncologic features of Saos2-1uc cells were analyzed. The OS was established as orthotopic xenografts in nude mice. Both orthotopic tumors and spontaneous lung metastasis were analyzed. Results Tumorigenesis and spontaneous lung metastasis in nude mice could be monitored in vivo through in vivo imaging system. The enhancement in proliferation, migration and invasion abilities and the attenuation in adhesion ability were observed in Saos2-1uc cells compared with Saos2 cells. Furthermore, there were the up-regulation of Osteocalcin, CCRIO, CXCR1 and ID1 and the down-regulation of ALP, collagen I, CCR1, CCR3, CXCR3, NID and N-cadherin in Saos2-1uc cells compare to Saos2 cells. The rate of spontaneous lung metastasis in Saos2-1uc cells was higher than that in Saos2 cells, although without significant difference. Conclusions Lentivirus transfection may cause alteration of gene expression profiles and further biological functions. This model can be used in the elucidation of molecular mechanisms of tumorigenesis and the screening of new therapeutic agents.展开更多
A number of solid tumors contain a distinct subpopulation of cells, termed cancer stem cells (CSCs) which represent the source for tissue renewal and hold malignant potential and which would be responsible for therapy...A number of solid tumors contain a distinct subpopulation of cells, termed cancer stem cells (CSCs) which represent the source for tissue renewal and hold malignant potential and which would be responsible for therapy resistance. Today, the winning goal in cancer research would be to find drugs to kill both cancer cells and cancer stem cells, while sparing normal cells. Osteosarcoma is an aggressive pediatric tumor of growing bones that, despite surgery and chemotherapy, is prone to relapse. We have recently selected from human osteosarcoma MG63 cells a cancer stem-like cell line (3AB-OS), which has unlimited proliferative potential, high levels of stemness-related markers, and in vivo tumorforming capacity in xenograft assays. Here, we have shown that 3AB-OS cells can differentiate in vitro into endoderm-, mesoderm-and ectoderm-derived lineages. Cell differentiation is morphological, molecular and functional. We propose that this model system of 3AB-OS differentiation in vitro might have a number of useful purposes, among which the study of molecular mechanisms of osteosarcoma origin, and the analysis of factors involved in specification of the various cell lineages. We still do not know either what are the shared and distinguishing characters between CSCs and normal stem cells, or what is the reason why the cancer stem cells, like the normal stem cells, have the ability to differentiate toward the derivatives of the primary germ layers. It is possible that each of the differentiation capability may be exploited by CSCs to supply their needs of growing and surviving in hostile microenvironment.展开更多
基金This study was supported in part by the National Natural Sciences Foundation of China(No.30271314).
文摘Objective: To observe whether there is evidence for vascular channel formation by osteosarcoma cellsin vitro and to illustrate mechanism of vasculogenic mimicry in osteosarcoma.Methods: Osteosarcoma cell lines (U-2OS) were tested for their ability to form tubular networks in three-dimensional culture containing type I collagen. The structures of the tubular networks were observed under a phase contrast microscope and an electron microscope.Results: Observation under light microscopy and electron microscopy showed that high aggressive osteosarcoma cells line (U-2OS) formed networks containing channels when grown in three-dimensional culture containing type I collagen in the absence of endothelial cells or fibroblasts.Conclusion: These observations strongly suggest that aggressive osteosarcoma cells may generate vascular channels that facilitate tumor perfusion independent of tumor angiogenesis and have the ability of vasculogenic mimicry. Key words osteosarcoma cells line - vasculogenesis mimicry - angiogenesis - 3-dimensional cultures This study was supported in part by the National Natural Sciences Foundation of China (No. 30271314).
基金This project was a key scientific and technological program of Hubei Provicial Scientific and Technological Committee (No.002p1503).
文摘Objective: To find out a method of extraction and purification of bone morphogenetic protein (BMP) from osteosarcoma cell conditioned medium, and evaluate the biological activity of BMP.Methods: Conditioned medium of osteosarcoma cell lines (MG-63) was collected, concentrated and dialyzed. The concentrated protein was purified through gel chromatography on Sephcryl-S-100. The purified protein was tested by BMP monoclonal antibody (McAb), its molecular weight (MW) was determined by SDS-PAGE and its biological activity was demonstrated by heterotopic ossification.Results: The purified protein was proved to be BMP by BMP McAb, had a satisfactory heterotopic ossification, and its MW was about 21 kD.Conclusion: BMP existed in the conditioned medium of osteosarcoma cell and had a satisfactory biological activity after purification. Because osteosarcoma cell can be cultured and grew for a long timein vitro, this method will be helpful to a vast extraction of BMP and clinical application. Key words osteosarcoma cell - conditioned medium - bone morphogenetic protein - protein purification This project was a key scientific and technological program of Hubei Provicial Scientific and Technological Committee (No. 002p1503).
基金supported by National Nature Science Foundation of China(30700841)
文摘Objective: This study investigated the effects of rh-TRAIL with or without chemotherapeutic drugs on the apoptosis of the osteosarcoma cell line, MG-63, and the influence of chemotherapeutic drugs on changes in the expression of DR5 and YinYang 1 (YY1) in MG- 63 cells. Methods: The effects of treatment with rh-TRAIL alone and/or chemotherapetic drugs on MG-63 cell growth inhibition and apoptosis were measured using the MTT assay, FACS analysis ofAunexin V labeled cells, and the mRNA changes of DR5 and YY1 were detected by RT-PCR. Results: Rh-TRAIL protein inhibited the growth of MG-63 cells, and this inhibition was increased by adriamycin and IFN-γ. Adriamycin and IFN-γ significantly facilitated the induction of the expression of DR5 and reduced the expression of YY1. Conclusion: The apoptosis-inducing effect of rh-TRAIL in MG-63 cells was enhanced by chemotherapeutic drugs.
基金Supported by the Natural Science Foundation of HubeiProvince (2003ABA163)Specialized Research Fund for the Doctoral Pro-gram of Higher Education (20060486049)
文摘This study is to examine the effect of human recombinant soluble TRAIL (TNF-related apoptosis-inducing ligand) protein inducing apoptosis in MG-63 human osteosarcoma cells. The inhibitive rates of TRAIL to MG-63 cells were detected by MTT assay. The apoptosis induced by TRAIL in MG-63 human osteosarcoma cells was analyzed with FACS and TUNEL and the apoptotic bodies were observed by transmission electron microscope. MTT assay showed that the inhibitive rates of 500, 1 000, 2 000 and 4 000 ng/mL TRAIL for 24 h were 10.1%, 24.3%, 50.6% and 97.7% respectively. Flow cytometric analysis showed that after MG-63 cells were treated with 2 gg/mL TRAIL for 6 h, obvious apoptotic peak would immediately appear before diploid peak. Human soluble TRAIL protein can quickly kill MG-63 osteosarcoma cells selectively, and may have potential value for clinical treatment of osteosarcoma.
文摘Objective: To investigate the inhibitory effects of LMWH suppressing the expression of Livin and inducing the apoptosis of the osteosarcoma cells. Methods: Osteosarcoma cells line MG-63 was cultured in vitro. MTT assay and flow cytometry were used to study the effect of LMWH with different concentration suppressed the prolifetation and induced apop- tosis in osteosarcoma cells line MG-63. The expression of Livin of osteosarcoma cells line MG-63 was analysed by the im- munohistochemistrical method and PT-PCR. Results: Low molecular weight heparin could inhibit the growth of osteosarcoma cell line MG-63. With the LMWH's increasing, the apoptosis rate was increased significantly. Immunohistochemistrical method and PT-PCR showed that the expression of Livin of osteosarcoma cells line MG-63 declined obviously than that before medi- cation. Conclusion: LMWH has very strong anti-tumor effect in vitro. The possible mechanisms of LMWH anti-tumor effect are associate with the effect of suppressing the expression of Livin and inducing cell apoptosis.
文摘Objective To characterize and compare the different biological behaviors of two novel human osteosarcoma cell lines,Zos and Zos-M,established respectively from the primary site and the skip metastasis of an osteosarcoma patient.Methods Two
文摘AIM:To investigate the effect of prednisolone,a synthetic glucocorticoid used in inflammatory diseases,on the growth of cultured osteosarcoma cells.METHODS:Two osteosarcoma cell lines with different degree of differentiation were used.SaOS2 show a rather mature phenotype,while U2 OS are negative for almost all osteoblastic markers.The cells were exposed to different concentrations of prednisolone(1-9 μmol/L) with or without antioxidants or the inhibitor of inducible nitric oxide synthase(i NOS) l-N6-(iminoethyl)-lysine-HCl(L-NIL).Cell growth was assessed by counting viable cells.The production of nitric oxide(NO) was measured in the conditioned media by the Griess method.The production of reactive oxygen species was quantified using 2'-7'-dichlorofluorescein diacetate.Western blot with specific antibodies against NOSs was performed on cell extracts.RESULTS:Prednisolone inhibited SaOS2 cell growth in a dose dependent manner.No significant effects were observed in U2OS.The inhibition of SaOS2 growth is not due to oxidative stress,because antioxidants do not rescue cell proliferation.Since high concentrations of NO inhibit bone formation,we also measured NO and found it induced in SaOS2,but not in U2 OS,exposed to prednisolone,because of the upregulation of i NOS as detected by western blot.Therefore,we treated SaOS2 with prednisolone in the presence or in the absence of L-NIL.L-NIL prevented NO release induced by prednisolone at all the concentrations apart from 9 μmol/L.At the same concentrations,we found that L-NIL rescued SaOS2 growth after exposure to prednisolone.In U2 OS cells,prednisolone did not induce NO production nor affected cell growth.All together,these data indicate that a link exists between increased amounts of NO and growth inhibition in response to prednisolone in SaOS2.CONCLUSION:Prednisolone inhibited SaOS2 proliferation by increasing the release of NO through the upregulation of i NOS,while no effect was exerted on U2OS.
文摘The effect of forskolin, an activator of adenylate cyclase, on glucocorticoid-induced modulation of proliferation and differentiation of a human osteosarcoma cell line(HOS-8603) was iniually studied. It was found that forskolin could significantly augment
文摘Objective: This study investigated the effect of NS398 on anti-proliferation and the mechanism of inducing apoptosis of human osteosarcoma cell MG-63 line in vitro. Methods: Growth suppression was detected by MTT method. Special morphological changes of apoptosis were observed by transmission electron microscopy (TEM) and DNA fragments electrophoresis. The apoptotic rates were quantified by flow cytometry (FCM). And Bcl-2 protein level were detected by Western Blotting assay. Results: Different concentration NS398 inhibited the cell growth. Through TEM and DNA electrophoresis, the special morphological changes were observed after 24, 48 and 72 h treatment with NS398. The apoptotic rates of MG-63 cells treated with NS398 were respectively, significantly higher than that of the control group( P 〈0.01 ). Western blot assay showed that NS398 reduced Bcl-2 protein expression. Conclusion: NS398 suppressed the proliferation of human osteosarcoma cell MG-63 line and induced apoptosis. The mechanism may be associated with down-regulation expression level of bcl-2 protein.
文摘The outcome of patients with osteosarcoma has not significantly improved in the last three decades. Therefore, there is still a need for the development of more effective therapeutic strategies. Methoxyamine (MX) is a base excision repair (BER) inhibitor that has shown anticancer potential by sensitizing a variety of tumor cells to ionizing radiation and chemotherapeutic drugs. In the present study, the in vitro antiproliferative effects of MX were evaluated in two osteosarcoma cell lines, HOS and MG-63. Evaluation of the influence on radiosensitivity and drug interactions in simultaneous treatments with methotrexate, doxorubicin, and cisplatin was also performed. Exposure to MX significantly decreased cell proliferation and mediated a substantial increase of apoptosis. Moreover, our results showed that MX synergized with ionizing radiation in both cell lines while potentiated the antitumor effects of cisplatin and methotrexate. Altogether, the results presented herein demonstrate the feasibility of inhibiting the BER pathway, which may in future be a promising strategy for overcoming intrinsic tumor resistance and to improve the outcome of patients with osteosarcoma.
基金Supported by the International Atomic Energy Agency
文摘The apoptosis of osteosarcoma cells treated with irradiation by 153Sm-EDTMP was studied. The morphological changes in osteosarcoma cells were observed by fluorescence microscopy. It was found that osteosarcoma cells exposed with 153Sm-EDTMP displayed significant nuclear fragmentation and marked pyknosis. With the prolongation of observing period, the membrane bound apoptotic bodies formation was observed. It should be noted, that with the lengthening of irradiation time by 153Sm-EDTMP, the inhibition rate of proliferation of osteosarcoma cells increased progressively.
文摘Background P-glycoprotein (P-gp) encoded by ATP-binding cassette sub-family B member 1 (ABCB1) gene is a kind of ATP-dependent drug transporter, which plays important roles in multidrug resistance (MDR) of human cancers, such as osteosarcoma. Curcumin is a natural phenolic coloring compound originating from the rhizomes of Curcuma Ionga, which is proved to possess antitumor biological activities including reversion of MDR. However, the effect and molecular mechanisms of curcumin to osteosarcoma MDR remain unclear.
文摘Previously,it has been found that glucocorticoid receptor(GR)binding activity decreasedrapidly during heat shock response in HOS-8603,a human osteosarcorna cell line.In this study,Therelationship between the induction of heat shock proteins(HSPs)and the decrease in GR was furtherstudied in the same cell line.It was found that even though quercetin could specifically inhibit the ex-pression of hsp90α and hsp70 mRNA,it could not prevent GR from the decrease in response to the heatshock treatment.This represents the first reported evidence that the induction of HSPs and the decrease inGR during heat shock response were 2 independent biological events.The results of the present study furthershowed that although the heat shock treatment alone had no effects on alkaline phosphatase(AKP)activity,itcould completely block the induction of AKP activity in HOS-8603 cells by dexamethasone(Dex),a syntheticglucocorticoid.These results demonstrate that the heat shock-induced alteration in GR was accompanied by adecrease in GR functional activity.Furthermore,when the induction of HSPs was inhibited by the treatmentof cells with quercetin,the stimulatory effects of Dex on AKP activity could still be inhibited completely bythe heat shock treatment.The results of this part,on the basis of GR functional activity,further demonstratethat quercetin could not inhibit the heat shock-induced decrease in GR,even though it could inhibit the induc-tion of HSPs.To clarify further the effects of quercetin alone on GR binding activity in HOS-8603 cells,theregulation of GR by quercetin was also studied.It was found for the first time that quercetin coulddown-regulate GR in a time-dependent manner significantly,and that the down-regulation of GR by quercetinin HOS-8603 cells paralelled with a decrease in glucocorticoid-mediated functional responses,suggesting thatthe down-regulation of GR by quercetin is of biological significance.
基金supported by grants from National Natural Science Foundation of China(No.30872967 and No.81072193to Jin Wang)from Natural Science Foundation of Guangdong Province(No.9151008901000096to Jin Wang)
文摘Osteosarcoma is the most common primary malignant bone cancer in children and adolescents.Emerging evidence has suggested that the capability of a tumor to grow is driven by a small subset of cells within a tumor,termed cancer stem cells(CSCs).Although several methods have been explored to identify or enrich CSCs in osteosarcoma,these methods sometimes seem impractical,and chemotherapy enrichment for CSCs in osteosarcoma is rarely investigated.In the present study,we found that short exposure to chemotherapy could change the morphology of osteosarcoma cells and increase sarcosphere formation in vitro,as well as increase tumor formation in vivo.Furthermore,methotrexate(MTX)-resistant U2OS/MTX300 osteosarcoma cells were larger in size and grew much more tightly than parental U2OS cells.More importantly,U2OS/MTX300 cells possessed a higher potential to generate sarcospheres in serum-free conditions compared to parental U2OS cells.Also,U2OS/MTX300 cells exhibited the side population(SP)phenotype and expressed CSC surface markers CD117 and Stro-1.Notably,U2OS/MTX300 cells showed a substantially higher tumorigenicity in nude mice relative to U2OS cells.Therefore,we conclude that chemotherapy enrichment is a feasible and practical way to enrich osteosarcoma stem cells.
基金the grants from the National Natural Science Foundation of China,the Shanghai Science and Technology Development Fund,the Program of Key Disciplines of Shanghai Municipal Education Commission,the Doctoral Innovation Foundation of Shanghai Jiaotong University
文摘Background Osteosarcoma (OS) is the most common primary malignant tumor of bone. Mouse models of human OS can invariably provide greater insight into the complex mechanisms that underlie the development and pathogenesis of this aggressive tumor. Bioluminescence technology favored tracing cancer cells in vivo. In this study, an OS model was described and evaluated using human OS cell line, Saos2, labeled with luciferase (Saos2-1uc). Methods Saos2 cells were infected by lentivirus loading a firefly luciferase gene. Luciferase expression of Saos2-1uc cells was characterized both in vitro and in vivo. Specific biologic and oncologic features of Saos2-1uc cells were analyzed. The OS was established as orthotopic xenografts in nude mice. Both orthotopic tumors and spontaneous lung metastasis were analyzed. Results Tumorigenesis and spontaneous lung metastasis in nude mice could be monitored in vivo through in vivo imaging system. The enhancement in proliferation, migration and invasion abilities and the attenuation in adhesion ability were observed in Saos2-1uc cells compared with Saos2 cells. Furthermore, there were the up-regulation of Osteocalcin, CCRIO, CXCR1 and ID1 and the down-regulation of ALP, collagen I, CCR1, CCR3, CXCR3, NID and N-cadherin in Saos2-1uc cells compare to Saos2 cells. The rate of spontaneous lung metastasis in Saos2-1uc cells was higher than that in Saos2 cells, although without significant difference. Conclusions Lentivirus transfection may cause alteration of gene expression profiles and further biological functions. This model can be used in the elucidation of molecular mechanisms of tumorigenesis and the screening of new therapeutic agents.
文摘A number of solid tumors contain a distinct subpopulation of cells, termed cancer stem cells (CSCs) which represent the source for tissue renewal and hold malignant potential and which would be responsible for therapy resistance. Today, the winning goal in cancer research would be to find drugs to kill both cancer cells and cancer stem cells, while sparing normal cells. Osteosarcoma is an aggressive pediatric tumor of growing bones that, despite surgery and chemotherapy, is prone to relapse. We have recently selected from human osteosarcoma MG63 cells a cancer stem-like cell line (3AB-OS), which has unlimited proliferative potential, high levels of stemness-related markers, and in vivo tumorforming capacity in xenograft assays. Here, we have shown that 3AB-OS cells can differentiate in vitro into endoderm-, mesoderm-and ectoderm-derived lineages. Cell differentiation is morphological, molecular and functional. We propose that this model system of 3AB-OS differentiation in vitro might have a number of useful purposes, among which the study of molecular mechanisms of osteosarcoma origin, and the analysis of factors involved in specification of the various cell lineages. We still do not know either what are the shared and distinguishing characters between CSCs and normal stem cells, or what is the reason why the cancer stem cells, like the normal stem cells, have the ability to differentiate toward the derivatives of the primary germ layers. It is possible that each of the differentiation capability may be exploited by CSCs to supply their needs of growing and surviving in hostile microenvironment.