Immediate early response gene X-1 (IEX-1) gene was discovered by Charles in 1993, which plays an important role in regulating apoptosis. Previous studies demonstrated that IEX-1 gene was expressed in a variety of human tissues and played an important role in regulating apoptosis and cell growth through a positive or negative way. It can inhibit cell growth and apoptosis. However, it can also promote cell apoptosis. There is evidence that IEX-1 is involved in viral infections and cardiovascular diseases and it is highly expressed in many tumor tissues. The regulatory mechanisms for IEX-1 under normal and pathophysiological conditions are complicated and remain largely unknown. In this paper, we reviewed the recent progress of IEX-1 in different disease models.
Apoptosis ; genetics ; Apoptosis Regulatory Proteins ; genetics ; physiology ; Cell Proliferation ; Humans ; Membrane Proteins ; genetics ; physiology ; Neoplasms ; genetics ; metabolism ; pathology ; Osteosarcoma ; metabolism ; pathology

OBJECTIVE: To observe the effect of different concentrations of nylestriol (NYL) and levonorgestrel (LNG) on the expression of ERα and ERβ in human osteoscarcoma MG-63 cell lines, and to explore the impact of paracrine effect on the gene expression. METHODS: MG-63 cells were treated with 3 concentrations (10(-10),10(-8), and 10(-6) mol/L) of NYL or LNG. The untreated control group and the positive control group were also established. The 2 groups treated with NYL (10(-10) mol/L) or LNG (10(-8) mol/L) were designed to renew the medium every 12 h. Semi-quantitative RT-PCR was conducted to detect the mRNA expression of ERα and ERβ on the MG-63 cells treated with different concentrations of the 2 drugs, respectively. RESULTS: Both drugs up-regulated ERα and ERβ mRNA expression. The best concentration for both NYL and LNG was 10(-6) mol/L for ERα expression. As for ERβ, the best concentration of NYL and LNG was 10(-10) mol/L and 10(-8) mol/L. The role of medium replacement on the expression of ERα was not observed, but medium replacement inhibited ERβ expression. CONCLUSION Both NYL and LNG can up-regulate the mRNA expression of ER subtypes in MG-63 cells, with mutual restriction between the 2 subtypes. The paracrine effect on MG-63 cell lines may be involved in the regulation process of mRNA expression of ERβ.
Cell Line, Tumor ; Estrogen Receptor alpha ; genetics ; metabolism ; Estrogen Receptor beta ; genetics ; metabolism ; Humans ; Levonorgestrel ; pharmacology ; Osteosarcoma ; metabolism ; pathology ; Quinestrol ; analogs & derivatives ; pharmacology ; RNA, Messenger ; genetics ; metabolism

OBJECTIVE: To investigate the prognostic value and mechanism of long non-coding RNA DLEU1(LncRNA DLEU1) in osteosarcoma. METHODS: The tissue samples and clinical data of 86 patients with osteosarcoma treated by orthopaedic surgery in our hospital from January 2012 to December 2014 were retrospectively collected. The expression of LncRNA DLEU1 in pathological tissues was detected by qRT-PCR, then the patients were divided into high and low expression of LncRNA DLEU1 groups. Osteosarcoma cell line HOS was divided into two groups, down-regulated expression group (si-DLEU1 group) and negative control group (si-NC group). LncRNA DLEU1 siRNA and negative control sequence were transfected by Lipofectamine 3000. Chi-square test was used to analyze the relationship between the expression of LncRNA DLEU1 and the clinicopathological factors of osteosarcoma. Kaplan-Meier method was used to compare the difference of the overall survival rate of osteosarcoma patients between the high and low expression groups of LncRNA DLEU1. The risk factors affecting the overall survival rate of osteosarcoma were analyzed by single factor and multifactor analysis. The number of invasive cells in the two groups was determined and compared by Transwell assay. RESULTS: The expression of LncRNA DLEU1 in osteosarcoma tissue was higher than that in adjacent tissues (P<0.001). The expression of LncRNA DLEU1 in human osteosarcoma cell lines (MG-63, U-2 OS, and HOS) was significantly higher than that in human osteoblast line hFOB 1.19 (P<0.001). The expression of LncRNA DLEU1 was significantly correlated with Enneking stage (P<0.001), distant metastasis (P=0.016), and histological grade (P=0.028). The 1-year overall survival rate of the LncRNA DLEU1 high expression group was significantly higher than that of the low expression group (90.7% vs 60.5%, P<0.001). The 5-year overall survival rate of the LncRNA DLEU1 high expression group was significantly higher than that of the low expression group (32.6% vs 11.6%, P<0.001). Univariate analysis showed that Enneking stage (P<0.001), tumor size (P=0.043), distant metastasis (P<0.001), histological grade (P<0.001), and expression of LncRNA DLEU1 (P<0.001) were risk factors for overall survival of osteosarcoma patients. Multivariate analysis showed that high expression of LncRNA DLEU1 [HR=1.948, 95% CI(1.141, 3.641), P=0.012] and distant metastasis[HR=4.108, 95% CI(2.169, 7.780), P<0.001] were independent risk factors for overall survival of osteosarcoma patients. The number of invasive cells in si-DLEU1 group was significantly lesser than that in si-NC group(139±13 vs 357±31, P<0.001). CONCLUSION High expression of LncRNA DLEU1 is a molecular marker affecting the prognosis of osteosarcoma patients. Downregulation of LncRNA DLEU1 can inhibit the invasion of osteosarcoma cells.
Humans ; Prognosis ; RNA, Long Noncoding/metabolism* ; Retrospective Studies ; Cell Proliferation/genetics* ; Cell Line, Tumor ; Osteosarcoma/genetics* ; Bone Neoplasms/pathology*

Studies have proved that microRNA-101 (miR-101) functions as a tumor suppressor and is associated with growth and apoptosis of various human cancers. However, the role of miR-101 in osteosarcoma and the possible mechanism by which miR-101 affects the tumor growth and apoptosis have not been fully elucidated. In this study, we found that the expression of miR-101 was down-regulated in osteosarcoma tissues and Saos-2 cell line as compared with that in adjacent non-neoplastic bone tissues and the osteoblastic cell line. To better characterize the role of miR-101 in osteosarcoma, we used a gain-of-function analysis by transfecting human osteosarcoma cell line Saos-2 with chemically synthesized miR-101 mimics. The results showed that overexpression of miR-101 inhibited the proliferation and promoted the apoptosis of Saos-2 cells. Meanwhile, bioinformatic analysis demonstrated that mTOR gene was a direct target of miR-101. Overexpression of miR-101 significantly decreased the expression of mTOR at both mRNA and protein levels in Saos-2 cells, consequently inhibiting Saos-2 cells proliferation and promoting cells apoptosis in an mTOR-dependent manner. Taken together, these data suggest that miR-101 may act as a tumor suppressor, which is commonly downregulated in both osteosarcoma tissues and cells. mTOR plays an important role in mediating miR-101 dependent biological functions in osteosarcoma. Reintroduction of miR-101 may be a novel therapeutic strategy by down-regulating mTOR expression.
Apoptosis ; Bone Neoplasms ; genetics ; metabolism ; pathology ; Cell Line, Tumor ; Cell Proliferation ; Humans ; MicroRNAs ; genetics ; metabolism ; Neoplasm Proteins ; genetics ; metabolism ; Osteosarcoma ; genetics ; metabolism ; pathology ; RNA, Neoplasm ; genetics ; metabolism ; TOR Serine-Threonine Kinases ; genetics ; metabolism

To compare the expression level of metastasis associated-1 (MTA1) gene in high and low metastatic human osteosarcoma cell lines and examine the relationship of MTA1 expression and the metastasis potentiality of osteosarcoma cells, the expression of MTA1 in MG-63 osteosarcoma cell lines with high and low metastasis potential was detected by semiquantitative TR-PCR. Boyden chamber invasion assay was used to evaluate the invasive capacity in vitro in two osteosarcoma cell lines. The low metastasis MG-63 cells were transfected with MTA1 full-length cDNA expression plasmid by lipofectamine and the changes of MTA1 expression and in vitro invasion potential were examined after the transfection. Our results showed that MG63 cell line with high metastasis potential expressed significantly higher MTA1 than that of MG63 cells with low metastasis as reavealed by RT-PCR. The invasion potential of low metastasis MG63 cell line was increased after MTA1 gene transfection. It is concluded that there may be a relationship between MTA 1 and invasive potentiality of human osteosarcoma cells, and the mechanism of MTA1 in osteosarcoma metastasis and its possible role in associated gene therapy deserve further study.
Bone Neoplasms/*metabolism ; Bone Neoplasms/pathology ; Gene Expression Regulation, Neoplastic ; Histone Deacetylases/*biosynthesis ; Histone Deacetylases/genetics ; Neoplasm Invasiveness ; Neoplasm Metastasis ; Osteosarcoma/*metabolism ; Osteosarcoma/pathology ; RNA, Messenger/biosynthesis ; RNA, Messenger/genetics ; Repressor Proteins/*biosynthesis ; Repressor Proteins/genetics ; Tumor Cells, Cultured

OBJECTIVETo study the influence of CD44 a cell-matrix adhesion molecule on the proliferation, adhesiveness and invasiveness of osteosarcoma cell lines, in order to investigate the growth and invasion mechanism of osteosarcoma.

METHODSThree osteosarcoma cell lines MG-63, HOS and U2-OS were routinely cultured. Flow cytometry and Western blot analysis were used for detecting the positive rates and relative amount of CD44 protein in the three cell lines. RT-PCR method was also used to compare the differences in the expression of CD44 mRNA among the 3 cell lines. Then, MTT method, adhesion detection, and Microcon-migration assay were used to detect the changes of the cells' proliferation rate, adhesive and invasive abilities after blocking the role of CD44 by using a special neutralizing antibody.

RESULTSThe results of flow cytometry showed that the percentage of CD44 positive cells were both over 99% in HOS and U2-OS, while that in MG-63 was only (2.10 +/- 0.46)%. The average fluorescence density of CD44 in HOS was significantly higher than in U2-OS. Western blot also showed that the relative content of CD44 protein in HOS was notably higher than that in U2-OS, while CD44 was negatively expressed in MG-63. The expression of CD44 mRNA was significantly lower in MG-63 than in both HOS and U2-OS, which were consistent with the expression of CD44 protein. The proliferation rates and adhesive abilities of MG-63 and HOS have no significant difference, but both were significantly higher than that of U2-OS. The invasive abilities of HOS was dramatically higher than MG-63 and U2-OS. After the role of CD44 was blocked by anti-CD44 neutralizing antibody, the proliferation rates of the 3 cell lines did not change significantly. While the HOS and MG-63 adhesion indices decreased dramatically (P < 0.05), the invasive abilities of HOS and U2-OS also decreased notably (P < 0.01).

CONCLUSIONSCD44 could promote the adhesiveness and invasiveness of osteosarcoma cell line HOS. CD44 may take part in promoting the process of U2-OS invasion and the adhesion of MG-63. On the other hand, CD44 could not affect the osteosarcoma cell proliferation rates.

Bone Neoplasms ; metabolism ; pathology ; Cell Adhesion ; Cell Line, Tumor ; Cell Proliferation ; Humans ; Hyaluronan Receptors ; biosynthesis ; genetics ; physiology ; Neoplasm Invasiveness ; Osteosarcoma ; metabolism ; pathology ; RNA, Messenger ; biosynthesis ; genetics

A recently identified protein, FAN1 (FANCD2-associated nuclease 1, previously known as KIAA1018), is a novel nuclease associated with monoubiquitinated FANCD2 that is required for cellular resistance against DNA interstrand crosslinking (ICL) agents. The mechanisms of FAN1 regulation have not yet been explored. Here, we provide evidence that FAN1 is degraded during mitotic exit, suggesting that FAN1 may be a mitotic substrate of the anaphase-promoting cyclosome complex (APC/C). Indeed, Cdh1, but not Cdc20, was capable of regulating the protein level of FAN1 through the KEN box and the D-box. Moreover, the up- and down-regulation of FAN1 affected the progression to mitotic exit. Collectively, these data suggest that FAN1 may be a new mitotic substrate of APC/CCdh1 that plays a key role during mitotic exit.
Anaphase-Promoting Complex-Cyclosome ; Bone Neoplasms ; metabolism ; pathology ; Cadherins ; genetics ; metabolism ; Cdc20 Proteins ; Cell Cycle Proteins ; genetics ; metabolism ; Cell Line, Tumor ; Exodeoxyribonucleases ; genetics ; metabolism ; HEK293 Cells ; Humans ; Mitosis ; Osteosarcoma ; metabolism ; pathology ; Ubiquitin-Protein Ligase Complexes ; genetics ; metabolism

OBJECTIVEUtilizing the hypoxia inducible factor 1/hypoxia reaction element (HIF-1/ HRE) gene regulation system to construct antisense vascular endothelial growth factor (VEGF165) cDNA eukaryotic expression vector promoted by HRE, and investigate its targeted inhibiting VEGF expression of osteosarcoma cells in hypoxia environment.

METHODSEukaryotic expression plasmid with HRE promoter was constructed containing luciferase reporter gene and antisense VEGF165 cDNA by using PCR and recombinant DNA techniques. The recombinant vectors were transfected into osteosarcoma cells with lipofectin method. Hypoxia-inducible reporter gene expression was determined by liquid scintillation analyzer and the expression of VEGF protein was detected by ELISA method.

RESULTSThe eukaryotic expression plasmid containing antisense VEGF165 and luciferase promoted by HRE was constructed successfully. After being transferred into MG63 cells, luciferase expression was increased 3.5 x 10(2) times and VEGF protein expression decreased 45% under hypoxia condition.

CONCLUSIONAntisense VEGF165 cDNA expression, efficiently realized by HRE promoter under hypoxia condition, provides an experimental basis for targeted antiangiogenesis of tumors.

Bone Neoplasms ; metabolism ; pathology ; Cell Hypoxia ; Cell Line, Tumor ; Genetic Vectors ; Humans ; Hypoxia-Inducible Factor 1 ; genetics ; Luciferases ; genetics ; metabolism ; Oligodeoxyribonucleotides, Antisense ; Osteosarcoma ; metabolism ; pathology ; Plasmids ; Promoter Regions, Genetic ; Recombinant Proteins ; genetics ; metabolism ; Transfection ; Vascular Endothelial Growth Factor A ; genetics ; metabolism

The purpose of this study was to examine the association of the expression of Sox4 and β-catenin with the prognosis of osteosarcoma. A total of 108 cases of conventional osteosarcoma were involved in this study and 28 cases of osteochondroma served as controls. The expression of Sox4 and β-catenin was detected by using immunohistochemical staining and Western blotting. The results showed that Sox4 and β-catenin were over-expressed in 67 (62.03%) and 62 (57.41%) of 108 osteosarcoma cases, while in only 3 (10.71%) and 5 (17.86%) of 28 controls, respectively (P<0.05 for all). The expression of Sox4 and β-catenin was associated with the distant metastasis, pathological grade and Enneking stage of patients with osteosarcoma (P<0.05 for all). The mean overall survival time and the 5-year-survival rate in osteosarcoma patients with Sox4 and β-catenin over-expressed were significantly reduced as compared with those in Sox4 and β-catenin low-expression group (P<0.05 for all). Cox multifactor regression analysis revealed that the distant metastasis, Enneking stage, and the expression of Sox4 and β-catenin were independent risk factors of patients with osteosarcoma (P<0.05 for all). The findings indicated that overexpression of Sox4 and β-catenin is associated with a poor prognosis of osteosarcoma.
Adolescent ; Adult ; Biomarkers, Tumor ; genetics ; metabolism ; Bone Neoplasms ; metabolism ; pathology ; Case-Control Studies ; Child ; Female ; Humans ; Lung Neoplasms ; metabolism ; secondary ; Male ; Middle Aged ; Osteosarcoma ; metabolism ; pathology ; SOXC Transcription Factors ; genetics ; metabolism ; beta Catenin ; genetics ; metabolism

BACKGROUNDEvidence shows that ezrin plays an important role in the development of some human malignancies. But the mechanism by which ezrin may affect tumor cell invasion and metastasis remains unclear.

METHODSIn this study, the expression of ezrin was verified in osteosarcoma (OS) cells and tissues by comparison with normal bone cells and tissues using Western blotting. OS-MG63 were transfected with pcDNA3.1-ezrin or pGenesil-1/shRNA-ezrin and the stably transfected cells were selected with G418 to yield the ezrin cell line. The OS-MG63 tumor cells were delivered by tail vein to female BALB/c to develop pulmonary metastasis model in vivo. Ezrin was identified as a direct target of miR-183 via a luciferase reporter carrying the 3'-untranslated region of ezrin. Migration assays and invasion assays were done with the transwells. Signaling pathway was studied by Western blotting and/or inhibitor.

RESULTSEctopic overexpression of ezrin in OS cell line MG63 promoted tumor cell invasion and migration. Consistent with this, knockdown of ezrin inhibited tumor cell invasion and migration. Similar results were obtained in the experimental metastasis model in vivo. We identified ezrin as a direct target of miR-183. What is more, ectopic expression of ezrin could induce the expression of N-cadherin and enhance the activity of extracellular signal-regulated kinase (ERK) signaling.

CONCLUSIONCollectively, these results suggest that ezrin as a direct target of miR-183 promotes the aggressiveness of OS via increased N-cadherin and activating ERK signaling.

Animals ; Bone Neoplasms ; metabolism ; pathology ; Cadherins ; genetics ; metabolism ; Cell Line, Tumor ; Cell Movement ; drug effects ; genetics ; Cytoskeletal Proteins ; genetics ; metabolism ; Female ; Humans ; In Vitro Techniques ; Mice ; Neoplasm Invasiveness ; genetics ; Osteosarcoma ; metabolism ; pathology