Commentary on:“Human neural stem cell-derived artificial organelles to improve oxidative phosphorylation”

Mitochondrial function is fundamental to neuroregeneration,particularly in neurons,where high energy demands are essential for repair and recovery(Patrón and Zinsmaier,2016;Beckervordersandforth et al.,2017;Iwata et al.,2023).Mitochondrial dysfunction,characterized by an imbalance in ATP levels and excessive production of mitochondrial reactive oxygen species,is a key factor that impedes neural regeneration in neurodegenerative diseases and after neuronal injury(Han et al.,2016,2020;Zheng et al.,2016;Zong et al.,2024).

Human endogenous retrovirus type-W and multiple sclerosis–related smoldering neuroinflammation

Introduction to human endogenous retrovirus type-W(HERV-W): Genomic inheritance from the past includes retroviral sequences that have been stably incorporated into our genomes and account for up to 8% of human DNA.

Treatment of spinal cord injury with biomaterials and stem cell therapy in non-human primates and humans

Spinal cord injury results in the loss of sensory,motor,and autonomic functions,which almost always produces permanent physical disability.Thus,in the search for more effective treatments than those already applied for years,which are not entirely efficient,researches have been able to demonstrate the potential of biological strategies using biomaterials to tissue manufacturing through bioengineering and stem cell therapy as a neuroregenerative approach,seeking to promote neuronal recovery after spinal cord injury.Each of these strategies has been developed and meticulously evaluated in several animal models with the aim of analyzing the potential of interventions for neuronal repair and,consequently,boosting functional recovery.Although the majority of experimental research has been conducted in rodents,there is increasing recognition of the importance,and need,of evaluating the safety and efficacy of these interventions in non-human primates before moving to clinical trials involving therapies potentially promising in humans.This article is a literature review from databases(PubMed,Science Direct,Elsevier,Scielo,Redalyc,Cochrane,and NCBI)from 10 years ago to date,using keywords(spinal cord injury,cell therapy,non-human primates,humans,and bioengineering in spinal cord injury).From 110 retrieved articles,after two selection rounds based on inclusion and exclusion criteria,21 articles were analyzed.Thus,this review arises from the need to recognize the experimental therapeutic advances applied in non-human primates and even humans,aimed at deepening these strategies and identifying the advantages and influence of the results on extrapolation for clinical applicability in humans.

Effects of P301L-TAU on post-translational modifications of microtubules in human iPSC-derived cortical neurons and TAU transgenic mice

TAU is a microtubule-associated protein that promotes microtubule assembly and stability in the axon.TAU is missorted and aggregated in an array of diseases known as tauopathies.Microtubules are essential for neuronal function and regulated via a complex set of post-translational modifications,changes of which affect microtubule stability and dynamics,microtubule interaction with other proteins and cellular structures,and mediate recruitment of microtubule-severing enzymes.As impairment of microtubule dynamics causes neuronal dysfunction,we hypothesize cognitive impairment in human disease to be impacted by impairment of microtubule dynamics.We therefore aimed to study the effects of a disease-causing mutation of TAU(P301L)on the levels and localization of microtubule post-translational modifications indicative of microtubule stability and dynamics,to assess whether P301L-TAU causes stability-changing modifications to microtubules.To investigate TAU localization,phosphorylation,and effects on tubulin post-translational modifications,we expressed wild-type or P301L-TAU in human MAPT-KO induced pluripotent stem cell-derived neurons(i Neurons)and studied TAU in neurons in the hippocampus of mice transgenic for human P301L-TAU(p R5 mice).Human neurons expressing the longest TAU isoform(2N4R)with the P301L mutation showed increased TAU phosphorylation at the AT8,but not the p-Ser-262 epitope,and increased polyglutamylation and acetylation of microtubules compared with endogenous TAU-expressing neurons.P301L-TAU showed pronounced somatodendritic presence,but also successful axonal enrichment and a similar axodendritic distribution comparable to exogenously expressed 2N4R-wildtype-TAU.P301L-TAU-expressing hippocampal neurons in transgenic mice showed prominent missorting and tauopathy-typical AT8-phosphorylation of TAU and increased polyglutamylation,but reduced acetylation,of microtubules compared with non-transgenic littermates.In sum,P301L-TAU results in changes in microtubule PTMs,suggestive of impairment of microtubule stability.This is accompanied by missorting and aggregation of TAU in mice but not in i Neurons.Microtubule PTMs/impairment may be of key importance in tauopathies.

Spatial transcriptomics combined with single-nucleus RNA sequencing reveals glial cell heterogeneity in the human spinal cord

Glial cells play crucial roles in regulating physiological and pathological functions,including sensation,the response to infection and acute injury,and chronic neurodegenerative disorders.Glial cells include astrocytes,microglia,and oligodendrocytes in the central nervous system,and satellite glial cells and Schwann cells in the peripheral nervous system.Despite the greater understanding of glial cell types and functional heterogeneity achieved through single-cell and single-nucleus RNA sequencing in animal models,few studies have investigated the transcriptomic profiles of glial cells in the human spinal cord.Here,we used high-throughput single-nucleus RNA sequencing and spatial transcriptomics to map the cellular and molecular heterogeneity of astrocytes,microglia,and oligodendrocytes in the human spinal cord.To explore the conservation and divergence across species,we compared these findings with those from mice.In the human spinal cord,astrocytes,microglia,and oligodendrocytes were each divided into six distinct transcriptomic subclusters.In the mouse spinal cord,astrocytes,microglia,and oligodendrocytes were divided into five,four,and five distinct transcriptomic subclusters,respectively.The comparative results revealed substantial heterogeneity in all glial cell types between humans and mice.Additionally,we detected sex differences in gene expression in human spinal cord glial cells.Specifically,in all astrocyte subtypes,the levels of NEAT1 and CHI3L1 were higher in males than in females,whereas the levels of CST3 were lower in males than in females.In all microglial subtypes,all differentially expressed genes were located on the sex chromosomes.In addition to sex-specific gene differences,the levels of MT-ND4,MT2A,MT-ATP6,MT-CO3,MT-ND2,MT-ND3,and MT-CO_(2) in all spinal cord oligodendrocyte subtypes were higher in females than in males.Collectively,the present dataset extensively characterizes glial cell heterogeneity and offers a valuable resource for exploring the cellular basis of spinal cordrelated illnesses,including chronic pain,amyotrophic lateral sclerosis,and multiple sclerosis.

Relationship between the Expression of MTA1 Gene and Invasion and Metastasis of Human Osteosarcoma Cells

Objective： To compare the expression level of metastasis associated-1 （MTA1） in the higher and lower metastasis sublines of human osteosarcoma cells （MG63）, and to investigate the relationship between the expression level of MTA1-EGFP and in vitro invasion and metastasis of human osteosarcoma cells. Methods： The expression level of MTA1 in two sublines of MG63 cells was detected by semi-quantitative RT-PCR, and cell invasion assay and cell proliferation assay were used to evaluate the invasive capacity in vitro in two sublines. The lower metastasis line of MG-63 cells were transfected with MTA1-EGFP full-length cDNA expression plasmid by lipofectamine. The changes of the MTA1-EGFP expression and in vitro invasion potential were measured after transfection. Results： M8 subline expressed significantly higher level of MTA1 than that of M6 subline by RT-PCR. The invasive potentials of low metastasis MG63 cell line were increased after MTA1 gene transfection. Conclusion： There may be a relationship between MTA1 and invasive potentials of human osteosarcoma cells, and MTA1 may play a role in the molecular mechanism of tumor metastases and be a potential target for gene therapy of osteosarcoma. Further studies of MTA1 in human ostersarcoma cell metastasis are needed.

p21^(WAF1/CIP1) Gene DNA Sequence Change and Their Relationship with the Phenotype of Human Osteosarcoma

Objective: To investigate the p21WAF1 /CIP1gene DNA sequence change and their relationship with the phenotype of human osteosarcoma. Methods: p21WAF1 /CIP1gene DNA of 36 osteosarcoma spec- imens was examined by using polymerase chain reaction-single strand conformation polymorphism (PCR- SSCP) method. The PCR products were sequenced directly. Results: In p21WAF1 /CIP1 gene exon3 of 36 cases of human osteosarcoma, the change of C→T in the p21WAF1 /CIP1gene CDNA sequence of position 609th occurred in 17 cases with the incidence being 44.4%. In 10 normal blood samples, DNA sequence analysis showed the change of C→T in the p21WAF1 /CIP1gene CDNA sequence of position 609th occurred in 8 cases with the incidence being 80%. Conclusion: The novel location of p21WAF1 /CIP1gene polymorphism of osteosarcoma, but not mutation was de?ned, and this location might provide the meaningful reference for the further research of p21WAF1/CIP1 gene.p2lWAF1/CIP1基因DNA序列分析及其与骨肉瘤表型的关系

Relationship between the Expression of MTA-1 Gene and the Metastasis and Invasion in Human Osteosarcoma

Summary：To compare the expression level of metastasis associated-1 （MTA 1 ） gene in high and low metastatic： human osteosarcoma cell lines and examine the relationship of MTA 1 expression and the metastasis potentiality of osteosarcoma cells, the expression of MTA 1 in MC-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 MTA 1 full-length cDNA expression plasmid by lipofectamine and the changes of MTA 1 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 MTA 1 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 MTA 1 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 MTA 1 in osteosarcoma metastasis and its possible role in associated gene therapy deserve further study.

Effect of MicroR NA-101 on Proliferation and Apoptosis of Human Osteosarcoma Cells by Targeting mTOR

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 os- teosarcoma and the possible mechanism by which miR-101 affects the tumor growth and apoptusis have not been fully elucidated. In this study, we found that the expression ofmiR-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 synthe- sized 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 ex- pression of roTOR at both mRNA and protein levels in Saos-2 cells, consequently inhibiting Saos-2 cells proliferation and promoting ceils 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, roTOR plays an important role in mediating miR-101 dependent bio- logical functions in osteosarcoma. Reintroduction of miR-101 may be a novel therapeutic strategy bydown-regulating mTOR expression.

Effect of PI3K-mediated autophagy in human osteosarcoma MG63 cells on sensitivity to the chemotherapy drug cisplatin

Objective: To investigate the influence of autophagy on sensitivity to the chemotherapy drug cisplatin(DDP) and the role of PI3 K in autophagy. Methods: MTT methods and l ow cytometer, with rapamycin up-regulating the autophagy and 3-MA down-regulating the autophagy, were employed to measure the proliferation inhibition rate on DDP-treated osteosarcoma cells and the change in cell cycle. The expression of intracellular protein was detected by Western blot. The autophagy of MG63 cell was observed using l uorescence microscope and transmission electron microscope. Results: Western blot showed that basic autophagy level of MG63 cell was significantly lower than that of h FOB cell. MTT test revealed that the cell proliferation inhibition rate in the group treated with rapamycin and DDP, group treated with 3-MA and DDP, and group only treated with DDP was signii cantly dif erent. It was demonstrated by the l ow cytometry that in group treated with DDP, inhibition on autophagy can increase the cell numbers in G1 phase and reduce the cell numbers in S phase of cell cycle. Increase of autophagosome in MG63 cytoplasm was observed under l uorescence microscope. Conclusions: Up-regulating the autophagy signii cantly reduced the sensitivity of MG63 cell to chemotherapy with DDP. DDP induced autophagy of MG63 cell and blocked the cell cycle at G1 phase.

Experimental Study on Inhibitory Effects of Diallyl Sulfide on Growth and Invasion of Human Osteosarcoma MG-63 Cells

The inhibitory effects of diallyl sulfide(DAS) derived from allicin on in vitro and in vivo proliferation of human osteosarcoma MG-63 cells and the action mechanism,and the influence of DAS on invasive capability of MG-63 cells were investigated in order to search for the novel medicines for osteosarcoma.In the in vitro experiment,MG-63 cells were treated with different concentrations of DSA,and the morphological changes of MG-63 cells were observed under an inverted phase microscope.MTT method was used to assay the proliferation of MG-63 cells.Semi-quantitative reverse transcription polymerase chain reaction(RT-PCR) was used to detect the VEGF mRNA expression level in MG-63 cells.By using Transwell invasion assay,the influence of DAS on invasive ability of MG-63 cells was tested.In the in vivo experiment,the nude mice MG-63 cells tumor-bearing model was established,and different concentrations of DAS were injected beside the tumor.Twenty-one days after treatment,the mice were killed,the tumor size and tumor inhibition rate were calculated.The microvessel density(MVD) was determined by using immunohistochemistry.In the in vitro experiment,different concentrations of DAS could obviously inhibit proliferation of MG-63 cells in a time-and concentration-dependent manner.RT-PCR revealed that the expression levels of VEGF mRNA in DSA groups(different concentrations) were significant reduced as compared with those in control group(all P<0.05).Transwell invasion assay indicated that in 20 and 40 μg/mL DAS groups,the number of migratory cells was 91.4±8.3 and 81.8±7.4 respectively,which was significantly declined as compared with that in control group(150.4±14.7,both P<0.05).In the in vivo experiment,DAS could significantly suppress the growth of MG-63 tumor-bearing tissue.Immunohistochemistry demonstrated that different concentrations(20 and 40 μg/mL) of DAS could significantly decrease MVD of MG-63 tumor-bearing tissue(all P<0.05).It was suggested that DAS could inhibit the growth of MG-63 cells probably by suppressing the expression of VEGF mRNA.

Involvement of MMP-2 in Adriamycin Resistance Dependent on ERK1/2 Signal Pathway in Human Osteosarcoma MG-63 Cells

Matrix metalloproteinase-2 (MMP-2) level and the ERK1/2 signal pathway are dependent factors for the growth and metastasis of cancer.However,the impact of MMP-2 in combination with ERK1/2 in tumor patients with drug resistance is unknown.To determine the relationship between MMP-2 and the ERK1/2 signal pathway,we established an adriamycin (ADM)-induced MG-63 (ADM-MG-63) cell line.With the increase of the ERK1/2 pathway blocker PD98059,we detected the expression levels of MMP-2 and p-ERK1/2 by Western blot in ADM-MG-63 cells.In ADM-MG-63 cells transfected with MMP-2-siRNA,the expression of ERK1/2 was detected for understanding the function of the ERK1/2 signal pathway.Three siRNAs for MMP-2 (MMP-2-siRNA) were designed,and the optimal one was selected and tested at different time points of 24,48 and 72 h.Under an ADM-induced condition,ADM-MG-63 cells were finally stable living in the medium of ADM (200 ng/mL).PD98059 could effectively suppress the expression levels of p-ERK1/2 and MMP-2.When the MMP-2 was silenced by using MMP-2-siRNA,the expression of p-ERK1/2 was enhanced.It is con-cluded that MMP-2 may be involved in ADM resistance dependent on ERK1/2 signal pathway,sug-gesting interference in ERK1/2 may be a new method of targeted therapy for tumor resistance.

MMP-1 Over-expression Promotes Malignancy and Stem-Like Properties of Human Osteosarcoma MG-63 Cells In Vitro

Osteosarcoma is the most common primary malignant bone tumor in childhood,and it maintains a high level of recurrence.Matrix metalloproteinase-1(MMP-1)was found to contribute to cancer progression.The present study was to investigate the in vitro effects of MMP-1 over-expression on the proliferation,invasion,metastasis and stem-like properties of osteosarcoma MG-63 cells.The MG-63 cells were cultured and had a full length MMP-1 cDNA inserted by the tentiviral vector (MG-63^MMP-1+).MG-63 negative control and MG-63 blank control groups were established as well.MMP-1 expression was detected in MG-63^MMP-1+,MG-63 negative control and MG-63 blank control cells using qPCR,Western blotting and immunofluorescence after 24h of culture. The cell proliferation assay was performed with a camera attached to a bioreactor,which was programmed to photograph five regions of each well every 10 min over a period of 48 h.The cell invasion assay was conducted with Matrigel to assess the invasive potential,of MG-63 cells over 24h,the qPCR analysis to measure stem cell markers,including Oct4, Sox-2,Nanog,and Pax-7,and Western blot analysis to detect invasive and metastatic potential markers TIMP-1,VEGF and BMP2/4,after 24h of culture.Immunofluorescence was used to investigate the presence of the stem cell marker Pax-7 after 24-h culture. The results showed that over-expression of MMP-1 after transfection could significantly increase minor cell proliferation and invasion (P<0.05,MG-63^MMP-1+ versus controls).Pax-7 was highly expressed in MG-63^MMP-1+ cells,with no significant changes of Oct-4,Sox-2, and Nanog observed (P<0.05).MG-63^MMP-1+ cells showed higher expression of VEGF and BMP 2/4 proteins and lower expression of TIMP-1 protein than controls (P<0.05).It was concluded that MMP-1 over-expression in MG-63 cells contributed to the proliferation, invasion,metastasis and stem-like properties of osteosarcoma cells.Future studies should focus on in vivo effects of MMP-1 over-expression and the application of MMP-1 and Pax-7 inhibition in vivo to osteosarcoma theraoies.

Study on Angiogenesis Factor of Human Osteosarcoma

Angiogenesis factor of human osteosarcoma was partially purified and its biological features were studied. The active peptide with 8000 to 10 000 u molecular weight in the conditioned medium obtained from the cultivation of human osteosarcoma cells were partially purified by ultrafiltration, chromatography and dialysis. The angiogenic effects of the fractions were assessed by proliferation assay of human umbilical vein and pig aorta thoracic endothelial cells. The results showed that the chromatography fractions of 4 to 6 could significantly promote the proliferation of the endothelial cells. It was suggested that the human osteosarcoma cells could synthesize and secrete angiogenesis factor with a molecular weight of 8000 to 10 000 u.

The Partial Purification of Angiogenesis Factor of Human Osteosarcoma

Objective To partially purify the angiogenesis factor of human osteosarcoma(HuOs) and study its biological features. Methods The active peptide with a molecular weight of 8000-10000 Da in the conditioned medium obtained from the cultivation of Hu-Os cells(osteoblastic osteosarcoma) was partially purified by ultrafiltration, chromatography and dialysis.The angiogenic effects of the fractions were assessed by proliferation assay of human umbilical vein and pig thoracic aorta endothelial cells. Results The chromatography fractions 4-6 could significantly promote the proliferation of the endothelial cells.Conclusion The HuOs cells could synthesize and secrete angiogenesis factor with a molecular weight of 8000-10000 Da.

VEGF-C/VEGFR-3/iNOS Signaling in Osteosarcoma MG63 Cells Mediates Stimulatory Effects on Human Umbilical Vein Endothelial Cell Proliferation

Objectives To assess the effects of vascular endothelial growth factor-C(VEGF-C)/vascular endothelial growth factor receptor-3(VEGFR-3)signaling on nitric oxide(NO)production and inducible nitric oxide synthase(iNOS)expression in human osteosarcoma MG63 cells and the subsequent impact on the proliferation of human umbilical vein endothelial cells(HUVECs).Methods MG63 cells were treated with VEGF-C alone(VEGF-C group),VEGF-C+iNOS inhibitor aminoguanidine(AG;AG group),and VEGF-C+VEGFR-3 inhibitor MAZ51(MAZ51 group);untreated MG63 cells were used as controls.NO production was evaluated by a colorimetric method involving nitrate reductase.Meanwhile,mRNA and protein levels of iNOS were examined by reverse transcription polymerase chain reaction(RT-PCR)and Western blot.To explore the effect of VEGF-C/VEGFR-3/iNOS signaling of MG63 cells on proliferation of HUVECs,we set up six groups:HUVECs,HUVECs+MG63,HUVECs+VEGF-C,HUVECs+MG63+VEGF-C,HUVECs+MG63+VEGF-C+AG,and HUVECs+MG63+VEGF-C+MAZ51 groups.The proliferation of HUVEC cells was assessed by Cell Counting Kit-8(CCK-8),5-ethynyl-2'-deoxyuridine(EdU)incorporation assay,and proliferating cell nuclear antigen(PCNA)expression quantitation.Results VEGF-C treatment enhanced iNOS expression at both gene and protein levels(mRNA:LSD-t=4.152,P<0.01;protein:LSD-t=3.486,P<0.01)and increased NO release of MG63 cells(LSD-t=3.774,P<0.01);treatment with either AG or MAZ51 decreased these effects(mRNA:LSD-t=9.183,P<0.001;LSD-t=8.639,P<0.001;protein:LSD-t=5.170,P<0.001;LSD-t=7.25S,P<0.001;NO production:LSD-t=10.326,P<0.001;LSD-t=l0.540,P<0.001).Interestingly,co-incubation of HUVECs with MG63 cells and/or VEGF-C significantly promoted HUVEC proliferation(EdU:LSD-t=5.374,P<0.001;LSD-t=2.984,P<0.05;LSD-t=8.526,P<0.001;PCNA:LSD-t=9.267,P<0.001;LSD-t=5.515,P<0.001;LSD-t=14.873,P<0.001).The proliferation effects of HUVEC induced by MG63 cells and VEGF-C attenuated by the treatment of AG(EdU:LSD-t=10.770,P<0.001;PCNA:LSD-t=19.94O,P<0.001)or MAZ51(EdU:LSD-t=6.950,P<0.001;PCNA:LSD-t=14.001,P<0.001).Conclusion In human osteosarcoma MG63 cells,activation of VEGFR-3 by VEGF-C promotes iNOS expression and NO production,which subsequendy induces HUVEC proliferation.

Establishment of a transplantation tumor model of human osteosarcoma in chick embryo

Objective: We established a transplantation tumor model of human osteosarcoma in chick embryo, studied its morphological and biological characteristics, and observed its dynamic process of angiogenesis induction so that a simple and practical model can be provided for studying osteosarcoma. Methods: Human osteosarcoma cells at different concentrations were inoculated in chorioallantoic membrane (CAM) of chick embryos at different embryonic ages to observe the factors affecting the survival of the transplanted osteosarcoma in chick embryo, growth characteristics of the transplantation tumor, and the morphological characteristics and biological characteristics of the transplantation tumor. Results: The transplantation tumor model of human osteosarcoma in chick embryo was successfully established. It was found that the transplantation tumor was easy to grow and it showed strong angiogenesis-inducing effects. Under the light microscope, the transplantation tumor showed a similar tissue structure to human osteosarcoma. Conclusion: It is feasible to establish a transplantation tumor model of human osteosarcoma in chick embryo. The model can be easily duplicated with a simple operation, which provides a useful animal model for studying osteosarcoma.

Establishment of nude mice model of human osteosarcoma cell MG63 with different potential of metastasis

Objective: To establish a nude mice model of human osteosarcoma lung metastasis. Methods: The growth of human osteosarcoma cell sublines M8 and M6 was determined by MTT assay. 2 × 107 cells were injected into the tail vein of nude mice. Mice were sacrificed started on week 4 after injection, and lung metastases were evaluated under both mac-roscopic and microscopic observation with HE staining. Results: The growth of low-metastatic subline M6 was lower than high-metastatic sublines M8. Seventeen mice after injected M8 had occurred lung metastases while only one mice had oc-curred in M6 group. Moreover, M8 cells within metastases were arrangement disorder with variable nuclear hyperchromasia. Conclusion: A mouse model for human osteosarcoma cancer lung metastasis can be established by injection different ability of metastasis MG63 cells into tail vein.

Molecular pathogenesis and therapeutic strategies of human osteosarcoma

Osteosarcoma（OS）is a devastating illness with rapid rates of dissemination and a poor overall prognosis,despite aggressive standard-of-care surgical techniques and combination chemotherapy regimens.Identifying the molecular mechanisms involved in disease pathogenesis and progression may offer insight into new therapeutic targets.Defects in mesenchymal stem cell differentiation,abnormal expression of oncogenes and tumor suppressors,and dysregulation within various important signaling pathways have all been implicated in development of various disease phenotypes.As such,a variety of basic science and translational studies have shown promise in identifying novel markers and modulators of these disease-specific aberrancies.Born out of these and similar investigations,a variety of emerging therapies are now undergoing various phases of OS clinical testing.They broadly include angiogenesis inhibitors,drugs that act on the bone microenvironment,receptor tyrosine kinase inhibitors,immune system modulators,and other radio-or chemo-sensitizing agents.As new forms of drug delivery are being developed simultaneously,the possibility of targeting tumors locally while minimizing systemic toxicityis is seemingly more achievable now than ever.In this review,we not only summarize our current understanding of OS disease processes,but also shed light on the multitude of potential therapeutic strategies the scientific community can use to make long-term improvements in patient prognosis.

Influence of β-catenin Small Interfering RNA on Human Osteosarcoma Cells

This study examined the effect of small interfering RNA-mediated β-catenin knockdown on the survival,invasion and chemosensitivity of human osteosarcoma cells（U2-OS cells）.The siRNA against β-catenin was constructed and transfected into U2-OS cells.The expression of β-catenin was detected by qRT-PCR and Western blotting.Cell growth and apoptosis was detected in the presence or absence of doxorubicin by MTT and flow cytometry,respectively.Cell invasion ability was measured by transwell assay.The results showed that the transfection of β-catenin siRNA resulted in decreased expression of β-catenin,suppression of invasion and motility of U2-OS cells,reduced chemosensitivity to doxorubicin in vitro,and little change in cell growth and apoptosis.Additionally,down-regulated MT1-MMP expression was found after transfection.It was concluded that knockdown of β-catenin gene may decrease the invasive ability of human osteosarcoma cells through down-regulated MT1-MMP expression,and the chemosensitivity of osteosarcoma cells against doxorubicin.