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Purpose: Osteosarcoma, a highly malignant primary bone tumor primarily affecting adolescents, frequently develops resistance to initial chemotherapy, leading to metastasis and limited treatment options. Our study aims to uncover novel therapeutic targets for metastatic and recurrent osteosarcoma., Methods: In this study, we proved the potential of modulating the YAP1-regulated glutamine metabolic pathway to augment the response of OS to DFMO. We initially employed single-cell transcriptomic data to gauge the activation level of polyamine metabolism in MTAP-deleted OS patients. This was further substantiated by transcriptome sequencing data from recurrent and non-recurrent patient tissues, confirming the activation of polyamine metabolism in progressive OS. Through high-throughput drug screening, we pinpointed CIL56, a YAP1 inhibitor, as a promising candidate for a combined therapeutic strategy with DFMO. In vivo, we utilized PDX and CDX models to validate the therapeutic efficacy of this drug combination. In vitro, we conducted western blot analysis, qPCR analysis, immunofluorescence staining, and PuMA experiments to monitor alterations in molecular expression, distribution, and tumor metastasis capability. We employed CCK-8 and colony formation assays to assess the proliferative capacity of cells in the experimental group. We used flow cytometry and reactive oxygen probes to observe changes in ROS and glutamine metabolism within the cells. Finally, we applied RNA-seq in tandem with metabolomics to identify metabolic alterations in OS cells treated with a DFMO and CIL56 combination. This enabled us to intervene and validate the role of the YAP1-mediated glutamine metabolic pathway in DFMO resistance., Results: Through single-cell RNA-seq data analysis, we pinpointed a subset of late-stage OS cells with significantly upregulated polyamine metabolism. This upregulation was further substantiated by transcriptomic profiling of recurrent and non-recurrent OS tissues. High-throughput drug screening revealed a promising combination strategy involving DFMO and CIL56. DFMO treatment curbs the phosphorylation of YAP1 protein in OS cells, promoting nuclear entry and initiating the YAP1-mediated glutamine metabolic pathway. This reduces intracellular ROS levels, countering DFMO's anticancer effect. The therapeutic efficacy of DFMO can be amplified both in vivo and in vitro by combining it with the YAP1 inhibitor CIL56 or the glutaminase inhibitor CB-839. This underscores the significant potential of targeting the YAP1-mediated glutamine metabolic pathway to enhance efficacy of DFMO., Conclusion: Our findings elucidate YAP1-mediated glutamine metabolism as a crucial bypass mechanism against DFMO, following the inhibition of polyamine metabolism. Our study provides valuable insights into the potential role of DFMO in an "One-two Punch" therapy of metastatic and recurrent osteosarcoma., (© 2024. Springer Nature Switzerland AG.)

Osteosarcoma (OS) is a primary malignant bone tumor that most commonly affects children, adolescents, and young adults. Here, we comprehensively analyze genomic, epigenomic and transcriptomic data from 121 OS patients. Somatic mutations are diverse within the cohort, and only TP53 is significantly mutated. Through unsupervised integrative clustering of the multi-omics data, we classify OS into four subtypes with distinct molecular features and clinical prognosis: (1) Immune activated (S-IA), (2) Immune suppressed (S-IS), (3) Homologous recombination deficiency dominant (S-HRD), and (4) MYC driven (S-MD). MYC amplification with HR proficiency tumors is identified with a high oxidative phosphorylation signature resulting in resistance to neoadjuvant chemotherapy. Potential therapeutic targets are identified for each subtype, including platinum-based chemotherapy, immune checkpoint inhibitors, anti-VEGFR, anti-MYC and PARPi-based synthetic lethal strategies. Our comprehensive integrated characterization provides a valuable resource that deepens our understanding of the disease, and may guide future clinical strategies for the precision treatment of OS., (© 2022. The Author(s).)

Osteosarcoma derives from primitive bone-forming mesenchymal cells and is the most common primary bone malignancy. Therapeutic targeting of osteosarcoma has been unsuccessful; therefore, identifying novel osteosarcoma pathogenesis could offer new therapeutic options. CDK7 is a subunit within the general transcription factor TFIIH. We aim to explore the new mechanism by which CDK7 regulates osteosarcoma and our studies may provide new theoretical support for the use of CDK7 inhibitors in the treatment of osteosarcoma. Here, we investigate the molecular mechanism underlying the association between CDK7 and GRP78 in osteosarcoma. Specifically, we find that an E3 ubiquitin ligase TRIM21 binds and targets GRP78 for ubiquitination and degradation, whereas CDK7 phosphorylates GRP78 at T69 to inhibit TRIM21 recruitment, leading to GRP78 stabilization. Notably, a CDK7-specific inhibitor, THZ1, blunts osteosarcoma growth and metastasis. Combination treatment with CDK7 and GRP78 inhibitors yield additive effects on osteosarcoma growth and progression inhibition. Thus, simultaneous suppression of CDK7 and GRP78 activity represents a potential new approach for the treatment of osteosarcoma. In conclusion, the discovery of this previously unknown CDK7/GRP78 signaling axis provides the molecular basis and the rationale to target human osteosarcoma., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)

Objective: To retrospectively analyze and compare the relationship between the success rate of patient-derived xenograft (PDX) modeling of osteosarcoma and prognosis (3-year overall survival rate and disease-free survival rate) and incidence of lung metastasis., Methods: The sample group consisted of 57 osteosarcoma patients with definite pathological diagnoses from Shanghai General Hospital from 2015-2017. PDX models in 57 patients were analyzed by retrospective analyses. Among the patients currently inoculated, 20 were tumorigenic in the PDX model, and 37 were nontumorigenic. According to the tumorigenicity of PDXs, the corresponding osteosarcoma patients were divided into two groups. The effects of clinically related indicators on the model were retrospectively compared. The patients were followed, and the 3-year survival, 3-year disease-free survival (DFS), and lung metastasis rates were collected. The relationship between the modeling success and patient prognosis was investigated., Results: In the chemotherapy-treated group, the PDX modeling success rate was 17.4%, and in the nonchemotherapy group, the success rate was 47.1%. The success of PDX modeling was related to whether patients received chemotherapy. The success rate of PDX modeling is significantly reduced after receiving chemotherapy. The 3-year overall survival rate of the PDX-grafted group was 49.23%, and that of the PDX-nongrafted group was 65.71%. There was a significant difference between the two groups, showing a strong negative correlation between the 3-year survival rate and the success rate of the PDX model. The 3-year disease-free survival rate of the PDX-grafted group was 29.54%. The 3-year DFS of the PDX-nongrafted group was 50.34%. There was a significant difference between the two groups. Lower grafted rates indicate a higher DFS rate. The incidence of lung metastasis in the PDX-grafted group was 32.4%, and that in the nongrafted group was 13.1%. There was a significant difference between the two groups. The successful establishment of the PDX model indicates that patients are more likely to have lung metastases., Conclusions: The success of PDX modeling often indicates poor prognosis (low 3-year overall survival rate and disease-free survival rate) and a greater possibility of lung metastasis. Therefore, PDX modeling in osteosarcoma patients can accurately predict the prognosis of patients and the risk of lung metastasis in advance to help us develop better therapeutic strategies., (© 2022 The Authors. Orthopaedic Surgery published by Tianjin Hospital and John Wiley & Sons Australia, Ltd.)

Osteosarcoma is the most common primary malignant bone tumor in children and adolescents, with highly aggressive behavior and early systemic metastasis. The survival rates for osteosarcoma remain unchanged over the past two decades. Studies aiming to find new or alternative therapies for patients with refractory osteosarcoma are urgently needed. Anlotinib, a novel multi-targeted tyrosine kinase inhibitor (TKI), has exhibited encouraging clinical activity in NSLCC and soft tissue sarcoma, whereas its effect on osteosarcoma has not been studied. In our study, we investigated the anti-tumor activity and underlying mechanism of anlotinib in osteosarcoma. Various in vitro and in vivo models of human osteosarcoma were used to determine the anti-proliferative, anti-angiogenesis and anti-metastasis efficacy of anlotinib. Our results showed that anlotinib suppressed tumor growth and increased the chemo-sensitivity of osteosarcoma. In addition, anlotinib inhibited migration and invasion in osteosarcoma cells. Furthermore, in order to explore the anti-tumor mechanism of anlotinib, phospho-RTK antibody arrays were performed. These analyses confirmed that anlotinib suppressed the phosphorylation of MET, VEGFR2 and the downstream signaling pathway activation. Moreover, we demonstrated that anlotinib blocked hepatocyte growth factor (HGF)-induced cell migration, invasion and VEGF-induced angiogenesis. Notably, a 143B-Luc orthotopic osteosarcoma model further showed that anlotinib significantly inhibited growth and lung metastasis of implanted tumor cells. Our preclinical work indicates that anlotinib acts as a novel inhibitor of VEGFR2 and MET that blocks tumorigenesis in osteosarcoma, which could be translated into future clinical trials., (© 2019 UICC.)

Osteosarcoma (OS) is ranked as the most common primary bone malignancy in children and adolescents worldwide, and the 5-year overall survival rate of OS is not optimistic. Constitutive activation of signal transducer and activator of transcription 3 (STAT3) has been implicated in tumor cell growth, proliferation, and anti-apoptosis in OS. Therefore, the discovery of novel molecular compounds that can effectively block STAT3 activation, is essential for the treatment of OS and improving prognosis. Here, we investigate whether Glaucocalyxin A (GLA), derived from Rabdosia japonica, exhibit the potential anticancer effects in OS. First of all, we identify that GLA potently suppressed cell proliferation, induced G2/M phase arrest and promoted substantial apoptosis in OS. Next, we conclude that GLA could induce Reactive oxygen species (ROS)-mediated oxidative stress via an imbalance of GSH and GSSG. Then, we elucidate for the first time that GLA could significantly inhibit both constitutive and IL-6-inducible activation of STAT3 (Tyr705) and JAK2, the upstream regulator of STAT3. Furthermore, we elucidate that the inhibition of STAT3 is mainly induced by ROS-mediated oxidative stress. Overall, our findings demonstrate that GLA could exhibit potent anticancer effects through effectively blocking the STAT3 signaling pathway, which was induced by ROS-mediated oxidative stress in OS in vitro and in vivo., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Osteosarcoma (OS) is the most common primary malignant bone tumor in children and adolescents. The abilities of chemotherapy resistance are major roadblock in the successful treatment of OS. The clarification of mechanism regarding cell survival during OS chemotherapy are important. Here, we examined HER4 expression by immunohistochemistry in a large series of OS tissues, and found HER4 expression correlated with tumor characteristics and patient survival rates. HER4 knockdown by shRNA inhibited OS cell growth and tumorigenesis, and induced cell senescence and apoptosis in vitro and in vivo. We demonstrated that HER4 expression upregulated in the adverse conditions, such as serum starvation and sphere culture. Moreover, HER4 knockdown cells became more sensitive in stressful conditions such as loss of attachment, cytotoxic agents or nutrition insufficiency. Mechanism studies revealed that HER4 interacted with NDRG1, and NDRG1 overexpression could antagonize HER4 knockdown-mediated cell growth and apoptosis in stressed conditions. There was a positive correlation between HER4 and NDRG1 immunoreactivity in OS patients. Together, our present study shows that HER4 and/or NDRG1 might play a critical role for the cell survival and chemo-resistance of OS, and could be used as potential therapeutic targets in OS., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Purpose: Osteosarcoma is the most common primary bone cancer and is notorious for pulmonary metastasis, representing a major threat to pediatric patients. An effective drug targeting osteosarcoma and its lung metastasis is urgently needed., Design: In this study, a sarcoma-targeting peptide-decorated disulfide-crosslinked polypeptide nanogel (STP-NG) was exploited for enhanced intracellular delivery of shikonin (SHK), an extract of a medicinal herb, to inhibit osteosarcoma progression with minimal systemic toxicity., Results: The targeted, loaded nanogel, STP-NG/SHK, killed osteosarcoma cells by inducing RIP1- and RIP3-dependent necroptosis in vitro . Necroptosis is a novel cell death form that could be well adapted as an efficient antitumor strategy, the main obstacle of which is its high toxicity. After intravenous injection, STP-NG/SHK efficiently suppressed tumor growth and reduced pulmonary metastasis, offering greater tumor necrosis and higher RIP1 and RIP3 upregulation compared to free SHK or untargeted NG/SHK in vivo . Additionally, the treatment with NG/SHK or STP-NG/SHK showed minimal toxicity to normal organs, suggesting low systemic toxicity compared to free SHK., Conclusion: The STP-guided intracellular drug delivery system using the necroptosis mechanism showed profound anti-osteosarcoma activity, especially eliminated lung metastasis in vivo . This drug formulation may have great potential for treatment of osteosarcoma., Competing Interests: Competing Interests: The authors have declared that no competing interest exists.

Combretastatin A-4 (CA-4), a tubulin-depolymerizing agent, shows promising antitumor efficacy and has been under several clinical trials in solid tumors for 10 years. Autophagy has an important pro-survival role in cancer therapy, thus targeting autophagy may improve the efficacy of antitumor agents. N-myc downstream-regulated gene 1 (NDRG1) is a significant stress regulatory gene, which mediates cell survival and chemoresistance. Here we reported that CA-4 could induce cell-protective autophagy, and combination treatment of CA-4 and autophagy inhibitor chloroquine (CQ) exerted synergistic cytotoxic effect on human osteosarcoma (OS) cells. Meanwhile, CA-4 or CQ could increase the expression of NDRG1 independently. We further performed mechanistic study to explore how CA-4 and CQ regulate the expression of NDRG1. Using luciferase reporter assay, we found that CA-4 transcriptionally upregulated NDRG1 expression, whereas CQ triggered colocalization of NDRG1 and lysosome, which subsequently prevented lysosome-dependent degradation of NDRG1. Further, we showed that knockdown of NDRG1 caused the defect of lysosomal function, which accumulated LC3-positive autophagosomes by decreasing their fusion with lysosomes. Moreover, NDRG1 inhibition increased apoptosis in response to combination treatment with CA-4 and CQ. Taken together, our study revealed abrogation of NDRG1 expression sensitizes OS cells to CA-4 by suppression of autophagosome-lysosome fusion. These results provide clues for developing more effective cancer therapeutic strategies by the concomitant treatment with CA-4 and clinical available autophagy inhibitors.

Osteosarcoma is a common primary malignant bone tumor, the cure rate of which has stagnated over the past 25-30 years. Arsenic sulfide (As 2 S 2 ), the main active ingredient of the traditional Chinese medicine realgar, has been proved to have antitumor efficacy in several tumor types including acute promyelocytic leukemia, gastric cancer and colon cancer. Here, we investigated the efficacy and mechanism of As 2 S 2 in osteosarcoma both in vitro and in vivo. In this study, we demonstrated that As 2 S 2 potently suppressed cell proliferation by inducing G2/M phase arrest in various osteosarcoma cell lines. Also, treatment with As 2 S 2 induced apoptosis and autophagy in osteosarcoma cells. The apoptosis induction was related to PARP cleavage and activation of caspase-3, -8, -9. As 2 S 2 was demonstrated to induce autophagy as evidenced by formation of autophagosome and accumulation of LC3II. Further studies showed that As 2 S 2 -induced apoptosis and autophagy could be significantly attenuated by ROS scavenger and JNK inhibitor. Moreover, we found that As 2 S 2 inhibited Akt/mTOR signaling pathway, and suppressing Akt and mTOR kinases activity can increase As 2 S 2 -induced apoptosis and autophagy. Finally, As 2 S 2 in vivo suppressed tumor growth with few side effects. In summary, our results revealed that As 2 S 2 induced G2/M phase arrest, apoptosis, and autophagy via activing ROS/JNK and blocking Akt/mTOR signaling pathway in human osteosarcoma cells. Arsenic sulfide may be a potential clinical antitumor drugs targeting osteosarcoma., (Copyright © 2017. Published by Elsevier Inc.)

Osteosarcoma (OS) is the most frequent primary malignant bone tumour. Alternol, a novel compound purified from microbial fermentation products exerts anti-tumour effects across several cancer types. The effect of alternol on human OS remains to be elucidated. We first evaluated the anti-tumour effect of alternol in several human OS cell lines in vitro and investigated its underlying mechanism. Alternol inhibited OS cell proliferation, migration and induced caspase-dependent apoptosis, G2/M cell cycle arrest in a dose and time-dependent manner. Moreover, alternol treatment inhibited signal transducer and activator of transcription-3 (STAT3) phosphorylation in 143B and MG63 human OS cells, as evaluated using a STAT3-dependent dual luciferase reporter system. Exposure to alternol resulted in excessive reactive oxygen species (ROS) generation and Jun amino-terminal kinases (JNK), extracellular signal-regulated kinases (ERK1/2) and p38 activation. Furthermore, alternol-induced cell death was significantly restored in the presence of the ROS scavenger, N-acetyl-l-cysteine (NAC) or a caspase inhibitor Z-VAD-FMK. NAC also prevented G2/M phase arrest and phosphorylation of mitogen-activated protein kinases (MAPK), but did not reverse STAT3 inactivation. Finally, alternol suppressed tumour growth in vivo in the nude mouse OS tibia orthotopic model. Immunohistochemistry revealed that alternol treatment resulted in down-regulation of phosph-STAT3 Tyr705 and up-regulation of cleaved caspase-3 and phosph-SAPK (Stress-activated protein kinases)/JNK expression. Taken together, our results reveal that alternol suppresses cell proliferation, migration and induces apoptosis, cell cycle arrest by modulating of ROS-dependent MAPK and STAT3 signalling pathways in human OS cells. Therefore, alternol is a promising candidate for developing anti-tumour drugs target OS., (© 2016 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.)

CD151, a tetraspanin family protein involved in cell-cell and cell-extracellular matrix interaction, is differentially expressed in osteosarcoma cell membranes. Thus, this study aimed to investigate the role of CD151 in osteosarcoma metastasis. We analyzed CD151 expression in patient tissue samples using immunohistochemistry. CD151 expression was also silenced with shRNA in osteosarcoma cells of high metastatic potential, and cell adhesion, migration and invasion were evaluated in vitro and pulmonary metastasis was investigated in vivo. Mediators of cell signaling pathways were also examined following suppression of CD151 expression. Overall survival for patients with low versus high CD151 expression level was 94 vs. 41 months (p=0.0451). CD151 expression in osteosarcoma cells with high metastatic potential was significantly higher than in those with low metastatic potential (p<0.001). shRNA-mediated silencing of CD151 did not influence cell viability or proliferation; however, cell adhesion, migration and invasion were all inhibited (all p<0.001). In mice inoculated with shRNA-transduced osteosarcoma cells, the number and size of lung metastatic lesions were reduced compared to the mice inoculated with control-shRNA transduced cells (p<0.001). In addition, CD151 knockdown significantly reduced Akt, p38, and p65 phosphorylation as well as focal adhesion kinase, integrin β1, p70s6, and p-mTOR levels. Taken together, CD151 induced osteosarcoma metastasis likely by regulating cell function through adhesion signaling. Further studies are necessary to fully explore the diagnostic and prognostic value of determining CD151 expression in osteosarcoma patients.

The gelsolin (GSN) has been involved in the regulation of tumor formation and development, but the biological role of GSN in the pathogenesis of osteosarcoma (OS) has not been well characterized. In this study, we show that high expression of GSN was observed in OS tissues and correlated with tumor size, advanced Enneking stage, and poor patient prognosis. Knockdown of GSN significantly inhibited cell proliferation and invasiveness in the OS cell lines. Furthermore, stable overexpression of GSN in OS cells resulted in a significant increase in cell growth and motility with the downregulation of p-AKT and p-P38 pathway. Finally, overexpression of GSN promoted growth of OS tumors in SCID mice. Taken together, these results provided the first evidence that GSN might contribute to OS cancer development and could be an attractive therapeutic target for patients with OS.

This study was carried out to investigate the anti-tumor effect and mechanism of hiporfin-mediated photodynamic therapy (hiporfin-PDT) in osteosarcoma. We found that hiporfin accumulated mainly in the cytoplasm of osteosarcoma cells in a time and concentration-dependent manner. Hiporfin-PDT inhibited the proliferation, induced apoptosis and produced cell cycle arrest at G2M in osteosarcoma cell lines. Hiporfin-PDT increased the expression of cleaved-caspase-3, cleaved PARP-1, Bax and RIP1 while it decreased the expression of Bcl-2; in addition, low concentration of hiporfin increased LC3 conversion. Furthermore, cell death caused by hiporfin-PDT could be rescued by Nec-1 but not by Z-VAD-FMK. Production of reactive oxygen species was increased after hiporfin-PDT. In vivo studies showed a significant decrease in tumor volume and weight after hiporfin-PDT in all three tumor mouse models investigated (subcutaneous and orthotopic). Histological analysis showed widespread cell apoptosis and necrosis after treatment. Immunohistochemistry also showed upregulation of cleaved-caspase-3 and downregulation of Bcl-2 after hiporfin-PDT. These results indicate that hiporfin-PDT exhibits a killing effect in osteosarcoma both in vitro and in vivo, which is associated with apoptosis and necroptosis, while autophagy plays a protective role. All these findings shed light on a potential future clinical use for hiporfin in the treatment of osteosarcoma., (© 2015 The American Society of Photobiology.)

We investigated the antitumor effect and mechanism of hematoporphyrin monomethyl ether-mediated photodynamic therapy (HMME-PDT) in sarcomas. Intracellular uptake of HMME by osteosarcoma cells (LM8 and K7) was time- and dose-dependent, while this was not observed for myoblast cells (C2C12) and fibroblast cells (NIH/3T3). HMME-PDT markedly inhibited the proliferation of sarcoma cell lines (LM8, MG63, Saos-2, SW1353, TC71, and RD) (P<0.05), and the killing effect was improved with increased HMME concentration and energy intensity. Flow cytometry analysis revealed that LM8, MG63, and Saos-2 cells underwent apoptosis after treatment with HMME-PDT. Additionally, apoptosis was induced after HMME-PDT in a three-dimensional culture of osteosarcoma cells. Hoechst 33342 staining confirmed apoptosis. Cell death caused by PDT was rescued by an irreversible inhibitor (Z-VAD-FMK) of caspase. However, cell viability was not markedly decreased compared with the HMME-PDT group. Expression levels of caspase-1, caspase-3, caspase-6, caspase-9, and poly (ADP-ribose) polymerase (PARP) proteins were markedly up-regulated in the treatment groups and increased with HMME concentration as determined by western blot analysis. In vivo, tumor volume markedly decreased at 7-16 days post-PDT. Hematoxylin and eosin staining revealed widespread necrotic and infiltrative inflammatory cells in the HMME-PDT group. Immunohistochemistry analysis also showed that caspase-1, caspase-3, caspase-6, caspase-9, and PARP proteins were significantly increased in the HMME-PDT group. These results indicate that HMME-PDT has a potent killing effect on osteosarcoma cells in vitro and significantly inhibits tumor growth in vivo, which is associated with the caspase-dependent pathway.

Background/aims: Over the past decade, heat shock protein 90 (Hsp90) has emerged as a potential therapeutic target for cancer. However, the molecular mechanisms of down-regulation Hsp90 expression in osteosarcoma are incompletely understood. To develop potential therapy targeting Heat shock protein 90B1 (Hsp90B1), we studied the roles of miR- 223 in the proliferation and apoptosis of human osteosarcoma., Methods: pcDNA3.1(+)- miR-223 plasmid vectors were constructed and transfected into MG63 cells. Co-transfection of miR-223 expression vector with pMIR-Hsp90B1 (The recombined vector of pMIR-GLOTM luciferase vector containing Hsp90B1-3'UTR) led to the reduced activity of luciferase in a dual-luciferase reporter gene assay, suggesting that Hsp90B1 is a target gene of miR-223. Expression of HSP90B1 was detected by RT-PCR and western blotting analysis. Cell proliferation was determined using the MTT assay. Cell-cycle distribution and apoptosis were examined by flow cytometry. PI3K, p-Akt, Akt, mTOR, Bcl-2 and Bid were also detected by western blotting analysis. After a mouse xenograft model of human MG63 tumors was constructed, tumor growth, microvessel density and proliferation in each group was determined., Results: The pcDNA3.1(+)-miR-223 vector efficiently suppressed the expression of HSP90B1, while silencing miR-223 increased expression of Hsp90B1. Furthermore, overexpression of miR-223 results in significant inhibition of cell growth on culture plates. Moreover, cancer cells showed significant G0/G1 arrest and increased apoptosis due to gene silencing. Protein levels of PI3k, p-Akt, mTOR, and Bcl-2 were decreased, whereas Bid levels were increased. Microvessel density as assessed by CD34 levels and cell growth by PCNA levels decreased according to immunohistochemical analysis., Conclusion: Hsp90B1 is a direct target of miR-223 and miR- 223 may have a tumor suppressor function in osteosarcoma through the PI3K/Akt/mTOR pathway and could be used in anticancer therapies in osteosarcoma., (Copyright © 2012 S. Karger AG, Basel.)

Osteosarcoma (OS) is the most common primary malignant bone tumor in children and adolescents. To identify new biomarkers for early diagnosis of OS and novel therapeutic candidates, we carried out a plasma membrane proteomic study based on two-dimensional electrophoresis (2DE). The OS cell line MG-63 and the human osteoblastic cell line hFOB1.19 were adopted as the comparison model. We extracted plasma membrane by aqueous two-phase partition extraction. The proteins were separated through 2DE. We analyzed the differentially expressed proteins by Imagemaster software and then identified them by liquid chromatography-tandem mass spectrometry, and the location and function of differential proteins were searched through the Gene Ontology database. In total, 220 protein spots were separated by 2DE. Seven proteins with more than 2.0-folds of difference were successfully identified from 13 gel spots, with 6 up-regulated and 1 down-regulated. Gene Ontology analysis of the differentially expressed proteins indicated that these proteins were involved in seven kinds of functions including binding, structural, cell motility, receptor activity, electron carrier activity, NADH dehydrogenase (ubiquinone) activity, and transcription repressor activity. The up-regulation of NDRG1 was verified in osteosarcoma through Western blotting and by immunohistochemistry in paraffin-embedded tissues. The plasma membrane proteins identified in this study may provide new insights into osteosarcoma cancer biology and potential diagnostic and therapeutic biomarkers.

This study was undertaken to investigate the inhibitory effects of triterpenoid compound oleanolic acid and its synthetic derivatives on osteosarcoma cells in order to identify new therapeutic candidates for the treatment of this disease. We used the 3-(4,5-dimethyl-2 thiazolyl)-2,5-diphenyl tetrazolium bromide assay to assess the effect of oleanolic acid compounds on the proliferation of osteosarcoma cells. The effect of dextrose-oleanolic acid (the most potent oleanolic acid derivative) on apoptosis of osteosarcoma cells was evaluated using the Annexin-V method. The cell cycle of dextrose-oleanolic acid-treated cells was examined by flow cytometry, and the in vivo effects of dextrose-oleanolic acid were evaluated in a mouse osteosarcoma model. Oleanolic acid compounds had an overall inhibitory effect on the proliferation of osteosarcoma cells. Our in vitro data showed that the dextrose-oleanolic acid derivative brought about maximal inhibition of proliferation of osteosarcoma cells while inducing apoptosis. It could also inhibit the growth of osteosarcoma and decreased the rate of lung metastasis in vivo. Of the oleanolic acid derivatives, dextrose-oleanolic acid exhibited the most potent anti-osteosarcoma activity; it may represent a new frontier in the treatment of osteosarcoma.

Background: Osteosarcoma (OS) is the most common primary malignant tumor of bone in children and adolescents. However, the knowledge in diagnostic modalities has progressed less. To identify new biomarkers for the early diagnosis of OS as well as for potential novel therapeutic candidates, we performed a sub-cellular comparative proteomic research., Methods: An osteosarcoma cell line (MG-63) and human osteoblastic cells (hFOB1.19) were used as our comparative model. Plasma membrane (PM) was obtained by aqueous two-phase partition. Proteins were analyzed through iTRAQ-based quantitative differential LC/MS/MS. The location and function of differential proteins were analyzed through GO database. Protein-protein interaction was examined through String software. One of differentially expressed proteins was verified by immunohistochemistry., Results: 342 non-redundant proteins were identified, 68 of which were differentially expressed with 1.5-fold difference, with 25 up-regulated and 43 down-regulated. Among those differential proteins, 69% ware plasma membrane, which are related to the biological processes of binding, cell structure, signal transduction, cell adhesion, etc., and interaction with each other. One protein--CD151 located in net nodes was verified to be over-expressed in osteosarcoma tissue by immunohistochemistry., Conclusion: It is the first time to use plasma membrane proteomics for studying the OS membrane proteins according to our knowledge. We generated preliminary but comprehensive data about membrane protein of osteosarcoma. Among these, CD151 was further validated in patient samples, and this small molecule membrane might be a new target for OS research. The plasma membrane proteins identified in this study may provide new insight into osteosarcoma biology and potential diagnostic and therapeutic biomarkers.

Osteosarcoma ( OS) is the most frequent primary malignant bone tumour. Alternol, a novel compound purified from microbial fermentation products exerts anti-tumour effects across several cancer types. The effect of alternol on human OS remains to be elucidated. We first evaluated the anti-tumour effect of alternol in several human OS cell lines in vitro and investigated its underlying mechanism. Alternol inhibited OS cell proliferation, migration and induced caspase-dependent apoptosis, G2/M cell cycle arrest in a dose and time-dependent manner. Moreover, alternol treatment inhibited signal transducer and activator of transcription-3 ( STAT3) phosphorylation in 143B and MG63 human OS cells, as evaluated using a STAT3-dependent dual luciferase reporter system. Exposure to alternol resulted in excessive reactive oxygen species ( ROS) generation and Jun amino-terminal kinases (JNK), extracellular signal-regulated kinases (ERK1/2) and p38 activation. Furthermore, alternol-induced cell death was significantly restored in the presence of the ROS scavenger, N-acetyl- l-cysteine ( NAC) or a caspase inhibitor Z- VAD- FMK. NAC also prevented G2/M phase arrest and phosphorylation of mitogen-activated protein kinases (MAPK), but did not reverse STAT3 inactivation. Finally, alternol suppressed tumour growth in vivo in the nude mouse OS tibia orthotopic model. Immunohistochemistry revealed that alternol treatment resulted in down-regulation of phosph- STAT3 Tyr705 and up-regulation of cleaved caspase-3 and phosph-SAPK (Stress-activated protein kinases)/ JNK expression. Taken together, our results reveal that alternol suppresses cell proliferation, migration and induces apoptosis, cell cycle arrest by modulating of ROS-dependent MAPK and STAT3 signalling pathways in human OS cells. Therefore, alternol is a promising candidate for developing anti-tumour drugs target OS. [ABSTRACT FROM AUTHOR]

The gelsolin (GSN) has been involved in the regulation of tumor formation and development, but the biological role of GSN in the pathogenesis of osteosarcoma (OS) has not been well characterized. In this study, we show that high expression of GSN was observed in OS tissues and correlated with tumor size, advanced Enneking stage, and poor patient prognosis. Knockdown of GSN significantly inhibited cell proliferation and invasiveness in the OS cell lines. Furthermore, stable overexpression of GSN in OS cells resulted in a significant increase in cell growth and motility with the downregulation of p-AKT and p-P38 pathway. Finally, overexpression of GSN promoted growth of OS tumors in SCID mice. Taken together, these results provided the first evidence that GSN might contribute to OS cancer development and could be an attractive therapeutic target for patients with OS. [ABSTRACT FROM AUTHOR]

Osteosarcoma (OS) is the most common primary malignant bone tumor in children and adolescents. To identify new biomarkers for early diagnosis of OS and novel therapeutic candidates, we carried out a plasma membrane proteomic study based on two-dimensional electrophoresis (2DE). The OS cell line MG-63 and the human osteoblastic cell line hFOB1.19 were adopted as the comparison model. We extracted plasma membrane by aqueous two-phase partition extraction. The proteins were separated through 2DE. We analyzed the differentially expressed proteins by Imagemaster software and then identified them by liquid chromatography-tandem mass spectrometry, and the location and function of differential proteins were searched through the Gene Ontology database. In total, 220 protein spots were separated by 2DE. Seven proteins with more than 2.0-folds of difference were successfully identified from 13 gel spots, with 6 up-regulated and 1 down-regulated. Gene Ontology analysis of the differentially expressed proteins indicated that these proteins were involved in seven kinds of functions including binding, structural, cell motility, receptor activity, electron carrier activity, NADH dehydrogenase (ubiquinone) activity, and transcription repressor activity. The up-regulation of NDRG1 was verified in osteosarcoma through Western blotting and by immunohistochemistry in paraffin-embedded tissues. The plasma membrane proteins identified in this study may provide new insights into osteosarcoma cancer biology and potential diagnostic and therapeutic biomarkers. [ABSTRACT FROM AUTHOR]