Activity In Osteosarcoma Cells Research Articles

A novel Ni-based complex inducing apoptosis through mitochondrial dysfunction in osteosarcoma HOS cells

A novel Ni complex was synthesized and investigated for its impact on the activity of osteosarcoma cells. The results demonstrated a significant elevation in intracellular ROS levels upon exposure to the Ni complex in osteosarcoma HOS cells.

MiR-4270 acts as a tumor suppressor by directly targeting Bcl-xL in human osteosarcoma cells.

Chondrosarcomas and osteosarcomas are malignant bone tumors with a poor prognosis when unresectable or metastasized. Moreover, radiotherapy and chemotherapy could be ineffective. MiRNAs represent an alternative therapeutic approach. Based on high-throughput functional screening, we identified four miRNAs with a potential antiproliferative effect on SW1353 chondrosarcoma cells. Individual functional validations were then performed in SW1353 cells, as well as in three osteosarcoma cell lines. The antiproliferative and cytotoxic effects of miRNAs were evaluated in comparison with a positive control, miR-342-5p. The cytotoxic effect of four selected miRNAs was not confirmed on SW1353 cells, but we unambiguously revealed that miR-4270 had a potent cytotoxic effect on HOS and MG-63 osteosarcoma cell lines, but not on SaOS-2 cell line. Furthermore, like miR-342-5p, miR-4270 induced apoptosis in these two cell lines. In addition, we provided the first report of Bcl-xL as a direct target of miR-4270. MiR-4270 also decreased the expression of the anti-apoptotic protein Mcl-1, and increased the expression of the pro-apoptotic protein Bak. Our findings demonstrated that miR-4270 has tumor suppressive activity in osteosarcoma cells, particularly through Bcl-xL downregulation.

Abstract 2533: MAPK-driven MCL1 expression promotes osteosarcoma survival in the metastatic niche

Abstract We sought to identify dependencies of slow growing, chemo-resistant osteosarcoma cells that anchor in the metastatic niche. These dependencies yield insight into what allows early cells to survive in the hostile lung environment, as well as potential therapeutic targets. In our studies of metastatic colonization, we identified two distinct populations of osteosarcoma cells. The first, dubbed “anchor cells”, are prevalent in the early metastatic niche where they are hypo-proliferative and hyper-secretory. The second subpopulation, “growth cells”, proliferate rapidly and predominate as lesions begin to grow rapidly. To identify genes and pathways that differentiate anchor cells, we performed scRNAseq on early and late metastases and confirmed these findings with tissue staining of time-matched metastases. To identify ligands that might facilitate survival of anchor cells in the lung microenvironment and their source, we performed scRNAseq on normal and metastasis-bearing lungs at different stages of metastasis. To confirm osteosarcoma cells express receptors for the identified lung growth factors, we used an immunoassay to evaluate tyrosine kinase receptor expression at baseline and in response to lung epithelial cell-conditioned medium. To confirm the growth factors increased MAPK activity in osteosarcoma cells, we used live cell imaging on fluorescent pERK reporter cells, followed by immunofluorescence to determine if increased MAPK activity was necessary for increased MCL1 expression. To determine if MCL1 is a viable therapeutic target and selective for anchor cells, we treated tumor-on-lung anchor cell-rich spheroid models with a MCL1-selective BH3 mimetic, AZD5991, and quantified cell death. To optimize dosing and determine tolerance in vivo, we treated metastasis-bearing mice with different doses of AZD5991 +/- cyclophosphamide. We found anchor cells have upregulated ERK activity and MCL1 expression compared to growth cells. This activity is associated with production of several growth factors in the metastatic niche that can activate receptors expressed by osteosarcoma cells. Growth-factor induced ERK activity is necessary for increased MCL1 expression in osteosarcoma cells. We found expression of many growth factors produced by niche cells becomes augmented as osteosarcoma cells colonize the lung. Additionally, host cells within the niche express comparatively more growth factors early in the metastatic process, with macrophages representing a predominant source of growth factors. We found cells expressing higher levels of MCL1 are vulnerable to its inhibition in vitro. Metastatic burden decreased as the number of AZD5991 doses increased in vivo. Our data suggest growth factors in the lung activate ERK in the early metastatic niche, and ERK-dependent MCL1 expression is required for survival of anchor cells. MCL1-targeting agents may have utility in disrupting colonization of the lungs. Citation Format: Camille A. McAloney, Rawan Makkawi, Matthew V. Cannon, Amy C. Gross, Maren Cam, Emily Franz, Tatyana A. Vetter, Alexander E. Davies, Ryan D. Roberts. MAPK-driven MCL1 expression promotes osteosarcoma survival in the metastatic niche [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2533.

KMT5A Knockdown Suppresses Osteosarcoma Cell Proliferation and Metastasis Through Ꞵ-Catenin Signalling.

Osteosarcoma (OS) is the most common malignant solid bone tumor in children and young adults. We aimed to investigate the effects and cellular mechanisms of KMT5A on OS cell activity. The protein expression was evaluated in the clinical normal, adjacent and OS osteogenic tissues. Knockdown of KMT5A was achieved by KMT5A siRNAs in a human OS cell line, MG63, to detect cell proliferation and metastasis. KMT5A expression was upregulated in clinical OS tissues. Knockdown of KMT5A inhibited cell proliferation but enhanced cell death, with significantly reduced cyclinD1 and Bcl2 and increased cleaved-caspase9 levels. KMT5A knockdown also suppressed OS cell migration and invasion capacity and deceased MMP3 and vimentin expression. β-catenin levels were upregulated in OS tissues and blocking KMT5A resulted in a significant decline in β-catenin expression in the OS cells. Further administration of β-catenin activator remarkably increased protein levels of KMT5A, cyclinD1, Bcl2, MMP3, and vimentin, which showed reversed effects of KMT5A knockdown on OS cell activity. KMT5A knockdown plays an inhibitory role in OS cell proliferation and metastasis through β-catenin signalling, which provides basic evidence and suggests potential targets for OS therapeutic research.

Asiaticoside reverses M2 phenotype macrophage polarization-evoked osteosarcoma cell malignant behaviour by TRAF6/NF-κB inhibition

Context M2 phenotype macrophage polarization is an attractive target for therapeutic intervention. Asiaticoside (ATS) has multiple pharmacological functions. Objective This study investigates the effect of ATS on M2 phenotype macrophage polarization in osteosarcoma. Materials and methods The differentiation of human THP-1 monocytes into M0 phenotype macrophages was induced by 100 nM phorbol myristate acetate for 24 h, and treated with 20 ng/mL IL-4 and 20 ng/mL IL-13 for 48 h to obtain M2 phenotype macrophages. The function of ATS on the growth and invasion was investigated by cell counting kit-8, transwell, and western blot under the co-culture of M2 phenotype macrophages and osteosarcoma cells for 24 h. The mechanism of ATS on osteosarcoma was assessed using molecular experiments. Results ATS reduced the THP-1 cell viability with an IC50 of 128.67 μM. Also, ATS repressed the M2 phenotype macrophage polarization induced by IL-4/IL-13, and the effect was most notably at a 40 μM dose. ATS (40 μM) restrained the growth and invasion of osteosarcoma cells induced by M2 phenotype macrophages. In addition, ATS reduced the tumour necrosis factor receptor-associated factor 6 (TRAF6)/NF-κB activity in osteosarcoma cells and the TRAF6 knockdown reduced the growth and invasion of osteosarcoma cells induced by M2 phenotype macrophages. TRAF6 (2 μg/mL) attenuated the inhibitory effect of ATS on the growth and invasion of osteosarcoma cells caused by M2 phenotype macrophages. In vivo studies further confirmed ATS (2.5, 5, or 10 mg/kg) repressed osteosarcoma tumour growth. Discussion and conclusions ATS reversed M2 phenotype macrophage polarization-evoked osteosarcoma cell malignant behaviour by reducing TRAF6/NF-κB activity, suggesting ATS might be a promising drug for the clinical treatment of osteosarcoma.

Ruta Graveolens in Homeopathic Dilution Has In Vitro Antitumor Activity in Osteosarcoma Cells (U2OS) and Low Effect on Canine Mesenchymal Stem Cells (CTM)

Ruta graveolens belongs to the family Rutaceae, and it is used to treat inflammatory diseases and some cases of cancer due to its anti-inflammatory and analgesic properties. Osteosarcoma (OS) is a bone cancer that mainly affects children and adolescents and has a high index in dogs. The treatment of this cancer consists of high doses of chemotherapy, and resection of the area affected by cancer, thus making it a painful and invasive treatment for patients. Under this perspective, it is necessary to search for new forms of treatment that are less invasive and, at the same time, effective, considering that homeopathy is used as a complementary therapy and benefits the patient's quality of life. This study aimed to compare the in vitro action of the homeopathic medicine Ruta D35 on U2OS osteosarcoma cells and canine mesenchymal stem cells (MSC). Our results demonstrate that Ruta D35 has a toxic effect on U2OS cells (IC50 16.38µL/mL), reducing cell viability compared to MSC (IC50 67.38µL/mL). Therefore, Ruta D35 showed positive results in treating the OS U2OS line, demonstrating a potential activity in treating this cancer.

Tspan9 Induces EMT and Promotes Osteosarcoma Metastasis via Activating FAK-Ras-ERK1/2 Pathway

ObjectAt present, there are few effective treatment options available to patients suffering from osteosarcoma (OS). Clarifying the signaling pathways that govern OS oncogenesis may highlight novel approaches to treating this deadly form of cancer. Recent experimental evidence suggests that the transmembrane protein tetraspanin-9 (Tspan9) plays a role in tumor development. This study was thus formulated to assess the molecular role of Tspan9 as a regulator of OS cell metastasis.MethodsGene expression in OS cell lines was evaluated via qRT-PCR, while CCK-8, colony formation, Transwell, and wound healing assays were used to explore the in vitro proliferative, invasive, and migratory activities of OS cells. The relationship between Tspan9 and in vivo OS cell metastasis was assessed by injecting these cells into the tail vein of nude mice. Interactions between the Tspan9 and integrin β1 proteins were explored through mass spectrometric and co-immunoprecipitation, and Western blotting to assess the functional mechanisms whereby Tspan9 shapes OS pathogenesis.ResultsBoth primary OS tumors and OS cell lines commonly exhibited Tspan9 upregulation, and the knockdown of this tetraspanin suppressed the migration, invasion, and epithelial-mesenchymal transition (EMT) activity in OS cells, whereas Tspan9 overexpression resulted in opposite phenotypes. Tumor lung metastasis were significantly impaired in mice implanted with HOS cells in which Tspan9 was downregulated as compared to mice implanted with control HOS cells. Tspan9 was also found to interact with β1 integrin and to contribute to OS metastasis via the amplification of integrin-mediated downstream FAK/Ras/ERK1/2 signaling pathway.ConclusionThese data suggest that Tspan9 can serve as a promising therapeutic target in OS.

Efficient synthesis of benzosultams containing continuous quaternary carbons via trapping active ylides with cyclic N-sulfonyl ketimines

A rapid and efficient method for the synthesis of benzosultams containing continuous quaternary carbons in a one pot fashion has been developed with moderate to excellent yields at room temperature under air. The resulting products exhibit good anticancer activity in osteosarcoma cells.

Long non-coding RNA ASMTL-AS1 deteriorates the oncogenicity of osteosarcoma by decoying microRNA-342–3p and consequently raising ADAM9 expression

BackgroundTill now, little is known regarding expression pattern and specific roles of lncRNA ASMTL antisense RNA 1 (ASMTL-AS1) in osteosarcoma (OS). Therefore, our current research measured the expression of ASMTL-AS1 in OS, unveiled the roles of ASMTL-AS1 in the modulation of malignant characteristics of OS, and identified the downstream mechanism. MethodsThe regulatory actions of ASMTL-AS1 ablation in OS cells were explored utilizing loss-of-function experiments. Mechanistic studies were implemented utilizing bioinformatics analysis, luciferase reporter assay, RNA immunoprecipitation and rescue experiments. ResultsASMTL-AS1 expression in OS was elevated in both TCGA database and our own cohort. Interfering with ASMTL-AS1 restricted cell proliferation, migration and invasion while increasing cell apoptosis in vitro. Additionally, silencing ASMTL-AS1 blocked tumour growth in vivo. Mechanistically, ASMTL-AS1 could act as a competing endogenous RNA for microRNA-342–3p (miR-342–3p) and inhibit its activity in OS cells, consequently causing an increase in ADAM metallopeptidase domain 9 (ADAM9) levels. Furthermore, inhibiting miR-342–3p or upregulating ADAM9 abated silenced ASMTL-AS1-induced antitumour activity in OS cells. ConclusionASMTL-AS1 aggravated OS progression by regulating the miR-342–3p/ADAM9 axis.

PF-06409577 Activates AMPK Signaling and Inhibits Osteosarcoma Cell Growth.

Osteosarcoma (OS) is a common primary bone malignancy. We here investigated the potential activity of PF-06409577, a novel, potent, and direct activator of AMP-activated protein kinase (AMPK), against human OS cells. In established (U2OS, MG-63, and SaOs-2 lines) and primary human OS cells, PF-06409577 inhibited cell viability and proliferation, while inducing cell apoptosis and cell cycle arrest. PF-06409577 induced AMPK activation, mTORC1 inhibition, autophagy induction, and downregulation of multiple receptor tyrosine kinase inOS cells. AMPK inactivation by AMPKα1 shRNA, CRISPR/Cas9 knockout, or dominant negative mutation (T172A) was able to abolish PF-06409577-induced activity in OS cells. In vivo, PF-06409577 oral administration at well-tolerated doses potently inhibited growth of U2OS cells and primary human OS cells in severe combined immunodeficient mice. AMPK activation, mTORC1 inhibition, autophagy induction, as well as RTK degradation and apoptosis activation were detected in PF-06409577-treated xenografts. In conclusion, activation of AMPK by PF-06409577 inhibits OS cell growth.

Dual Functional Pd-Catalyzed Multicomponent Reaction by Umpolung Chemistry of the Oxygen Atom in Electrophiles.

A Pd-catalyzed multicomponent reaction was developed by trapping oxomium ylide with nitrosobenzene via Pd-promoted umpolung chemistry. The Pd catalyst plays two important roles: diazo compound decomposed catalyst and Lewis acid for the activation of nitrosobenzene. This strategy provides some insight into a new way for discovery of multicomponent methodology to construct complex molecules. The developed method also provides rapid access to a series of O-(2-oxy) hydroxylamine derivatives, which exhibit good anticancer activity in osteosarcoma cells.

Tideglusib suppresses stem-cell-like features and progression of osteosarcoma by inhibiting GSK-3β/NOTCH1 signaling

Osteosarcoma is the most common primary bone tumor in children, teenagers and adolescents. Cancer stem cells (CSCs) have the function to self-renew and keep the phenotype of tumor, causing clinical treatment failure. Therefore, developing effective therapies to inhibit osteosarcoma progression is urgently necessary. Glycogen synthase kinase 3β (GSK-3β)is highly expressed in osteosarcoma. In the present study, we made an exploration on the anti-tumor effect of tideglusib (TID), a small-molecule inhibitor of GSK-3β, and revealed the underlying mechanisms. Here, we found that TID markedly reduced the cell viability of different osteosarcoma cell lines. Cell cycle arrest distributed in G2/M was markedly up-regulated in TID-incubated osteosarcoma cells through enhancing p21 expression levels. Apoptosis was evidently induced in osteosarcoma cells via blocking Caspase-3 activation. Consistently, tumor growth was effectively suppressed in an established murine xenograft model with few toxicity and side effects in vivo. Furthermore, TID markedly repressed stem-cell-like activity in osteosarcoma cells through down-regulating NOTCH1 expression. Notably, rescuing NOTCH1 significantly abolished the role of TID in reducing cell proliferation and sarcosphere-formation. Mechanistically, we found that TID-inhibited NOTCH1 expression was associated with the blockage of AKT/GSK-3β signaling pathway. In summary, we for the first time provided evidence that TID could effectively inhibit osteosarcoma progression through repressing cell proliferation, inducing apoptosis, suppressing stem-cell-like properties via down-regulating AKT/GSK-3β/NOTCH1 signaling pathway. Thus, TID may be a promising therapeutic strategy for osteosarcoma treatment without side effects.

METTL14 Overexpression Promotes Osteosarcoma Cell Apoptosis and Slows Tumor Progression via Caspase 3 Activation.

BackgroundAs a key enzyme of m6A methylation modification, methyltransferase-like 14 (METTL14) is involved in many physiological and pathophysiological processes. This study aims to explore the effect of METTL14 on the viability of osteosarcoma cells and explain the underlying molecular mechanism.MethodsWe detected the content of METTL14 in osteosarcoma tissue by qRT-PCR and Western blot. Experiments such as transwell, EdU, and CCK-8 have demonstrated the effect of METTL14 on osteosarcoma cell activity. In addition, the regulation of caspase-3 by METL14 was determined by Western blot. We used caspase-3 inhibitor to further reverse the effect of METTL14 on osteosarcoma cell apoptosis.ResultsWe found that the expression of METTL14 in osteosarcoma cells was reduced compared with normal tissues. METTL14 overexpression significantly reduced the proliferation, migration, invasion and apoptosis of osteosarcoma cells. Inhibition of METL14 showed the opposite result. We have demonstrated that METTL14 finally achieves apoptosis by activating caspase-3.ConclusionWe have demonstrated that METTL14 has effects on osteosarcoma cell proliferation, migration, and invasion and promotes cell apoptosis by activating caspase-3, which may become a potential therapeutic target for osteosarcoma.

Tripartite Motif-Containing 46 Promotes Viability and Inhibits Apoptosis of Osteosarcoma Cells by Activating NF-B Signaling Through Ubiquitination of PPAR.

Osteosarcoma (OS), the most common bone cancer, causes high morbidity in children and young adults. TRIM46 is a member of the family of tripartite motif (TRIM)-containing proteins that serve as important regulators of tumorigenesis. Here we investigate the possible role of TRIM46 in OS and the underlying molecular mechanism. We report an increase in the expression of TRIM46 in OS and its association with tumor size, Enneking’s stage, and patient prognosis. TRIM46 knockdown inhibits OS cell viability and cell cycle progression and induces apoptosis, while TRIM46 overexpression exerts inverse effects, which are inhibited by peroxisome proliferator-activated receptor alpha (PPARα) overexpression and the nuclear factor kappa B (NF-κB) inhibitor, pyrrolidine dithiocarbamate (PDTC). Furthermore, TRIM46 negatively regulates PPARα expression via ubiquitination-mediated protein degradation and modification. PPARα overexpression also inactivates NF-κB signaling and NF-κB promoter activity in OS cells overexpressing TRIM46. Moreover, TRIM46 knockdown inhibits tumor growth and induces apoptosis of OS cells in vivo. TRIM46 acts as an oncogene in OS by interacting with and ubiquitinating PPARα, resulting in the activation of NF-κB signaling pathway. Thus, TRIM46 may be a potential biomarker of carcinogenesis.

RETRACTED: The Sp1/FOXC1/HOTTIP/LATS2/YAP/β‐catenin cascade promotes malignant and metastatic progression of osteosarcoma

The prognosis for osteosarcoma (OS) is dismal due to the aggressive tumor growth and high incidence of metastasis. The long noncoding RNA human homeobox A transcript at the distal tip (HOTTIP) and the transcription factor forkhead box C1 (FOXC1) present oncogenic activities in OS. Here, we aimed at gaining insights into the underlying mechanisms and their crosstalk. The expression of FOXC1 and HOTTIP in OS tissues or cell lines was examined by real-time PCR (RT-PCR) and western blot. The invitro effects of FOXC1 or HOTTIP on cell viability, proliferation, migration, invasion, and expression of target genes were examined using MTT, colony-forming assay, wound-healing, Transwell invasion, and western blot, respectively; the invivo effects were examined using xenograft and experimental metastasis models. Molecular control of HOTTIP on large tumor suppressor 2 (LATS2) or transactivation of FOXC1 or Sp1 on HOTTIP was assessed by combining RNA immunoprecipitation, qRT-PCR, western blot, ChIP, and luciferase assay. Both FOXC1 and HOTTIP were potently up-regulated in OS tissues and cell lines. FOXC1 and HOTTIP essentially maintained viability, proliferation, migration, and invasion of OS cells invitro and contributed to xenograft growth or lung metastasis invivo. Mechanistically, HOTTIP recruited enhancer of zeste homolog 2 (EZH2) and lysine-specific demethylase 1 (LSD1) to silence LATS2 and thus activated YAP/β-catenin signaling. Upstream, Sp1 activated FOXC1 and they both directly transactivated HOTTIP. In summary, we showed that the Sp1/FOXC1/HOTTIP/LATS2/YAP/β-catenin cascade presented oncogenic activities in OS cells. Targeting FOXC1 or HOTTIP may therefore prove beneficial for OS treatment.

LncRNA LSINCT5 Regulates miR-20a-5p/XIAP to Inhibit the Growth and Metastasis of Osteosarcoma Cells.

BackgroundMore and more evidence has shown that non-coding RNA (ncRNA), including long ncRNA (lncRNA) and micro RNA (miRNA), plays a crucial regulatory role in osteosarcoma (OS). Previously, we revealed a Rho-related coiled coil incorporating protein kinase 1(XIAP). A transfer-related gene is negatively regulated by microRNA-20a-5p (miR-20a-5p) and plays the role of oncogene in OS. It is not clear if any lncRNA is involved in the axial upstream of miR-20a-5p/XIAP.MethodsExpression of LSINCT5 and miR-20a-5p/XIAP in OS tissues was determined through qRT-PCR (qP). The proliferation and migration/invasion activity of OS cells were tested through CCK-8/and transwell assay, respectively. The changes on expression of XIAP were examined through qRT-PCR and Western blot (WB). Targeted binding between LSINCT5, miR-20a-5p, and XIAP has been verified using dual luciferase reporter gene analysis, RNA Immunoprecipitation (RIP), and RNA pull-down experiments. The effect of LSINCT5 on tumor growth was determined by tumor allograft test.ResultsIn this study, elevated LSINCT5 was found in OS tissue samples and OS cell strains, and the increased LSINCT5 was strongly related to the adverse prognosis of clinical patients. Functional assays showed that inhibition of LSINCT5 could up-regulate miR-20a-5p-mediated OS cells proliferation and metastasis. WB analysis and qP analysis showed that LSINCT5 regulated XIAP by mediating miR-20a-5p. Further cell behavior experiments showed that LSINCT5 acted as a miR-20a-5p sponge to inhibit proliferation and metastasis caused by XIAP. Finally, the results of animal models in vivo showed that LSINCT5 could regulate the tumor growth of OS.ConclusionLncRNA LSINCT5 acts as an oncogene and promotes XIAP mediated growth and metastasis as competitive endogenous RNA (ceRNA) in OS.

MicroRNA-618 Directly Targets Metadherin mRNA To Suppress The Malignant Phenotype Of Osteosarcoma Cells By Reducing PTEN-AKT Pathway Output.

PurposeDysregulation of microRNA-618 (miR-618) has been observed in multiple types of human cancer. However, whether miR-618 is implicated in osteosarcoma (OS) initiation and progression is still unclear. Hence, we measured the expression of miR-618 in OS tissues and cell lines. In addition, the roles of miR-618 and the mechanisms underlying its activities in OS cells were examined.MethodsThe expression status of miR-618 in OS was analyzed by reverse-transcription quantitative PCR. The regulatory roles of miR-618 overexpression in OS were explored by the Cell Counting Kit-8 assay, flow-cytometric analysis, Transwell cell migration and invasion assays, and a tumor xenograft experiment.ResultsThe results revealed that the expression of miR-618 was notably lower in OS tissues and cell lines, and that the low miR-618 expression significantly correlated with the clinical stage and distant metastasis among patients with OS. Exogenous miR-618 expression significantly suppressed OS cell proliferation, migration, and invasion and induced apoptosis in vitro as well as slowed tumor growth in vivo. Mechanism investigation indicated that metadherin (MTDH) is a direct target gene of miR-618 in OS cells. A knockdown of MTDH mimicked the tumor-suppressive effects of miR-618 upregulation on OS cells. Notably, resumption of MTDH expression attenuated the miR-618–mediated reduction in OS cell growth and metastasis in vitro. In addition, miR-618 overexpression reduced the PTEN–AKT pathway output in OS cells both in vitro and in vivo through downregulation of MTDH.ConclusionTo the best of our knowledge, this is the first study to show that miR-618 exerts crucial tumor-suppressive actions in OS pathogenesis by directly targeting MTDH mRNA and reducing PTEN–AKT pathway output. These results will help to elucidate the functions of miR-618 in OS and suggest that this miRNA may be investigated as a therapeutic target in this disease.

Salidroside suppresses the growth and invasion of human osteosarcoma cell lines MG63 and U2OS in vitro by inhibiting the JAK2/STAT3 signaling pathway.

Previous research has reported that salidroside exerts antitumor properties on numerous types of tumor cells; however, its effect on osteosarcoma cells remains unknown. The present study aimed to investigate the effects of salidroside on the viability, apoptosis and invasion of osteosarcoma cells in vitro, and determine the underlying mechanism of action. The results of an MTT revealed that salidroside suppressed the viability of osteosarcoma cells (MG63 and U2OS cells) in a time- and concentration-dependent manner. The results of cell morphological analysis (profile observations and Hoechst 33258 staining) and the detection of apoptosis by flow cytometry further indicated that the decrease in osteosarcoma cell viability induced by salidroside was associated with cell apoptosis. Western blot analysis not only confirmed these results but also suggested that salidroside induced the apoptosis of osteosarcoma cells by activating the caspase-9-dependent apoptotic pathway. In addition, we reported that salidroside induced G0/G1 phase arrest and suppressed the invasion of osteosarcoma cells, as measured by flow cytometric cell cycle analysis and a Transwell invasion assay, respectively. Western blot analysis confirmed the aforementioned results. Furthermore, our findings demonstrated that salidroside induced the apoptosis, G0/G1 phase arrest and suppressed the invasion of osteosarcoma cells by inhibiting the janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling pathway, as determined by western blot analysis. In summary, the findings of the present study suggested that salidroside may inhibit the progression of osteosarcoma by suppressing the growth and invasion of osteosarcoma cells. Furthermore, the investigations into the underlying mechanism demonstrated that salidroside exerted notable antitumor activity in osteosarcoma cells by inhibiting the JAK2/STAT3 signaling pathway.

Potential Regulatory Effects of miR-182-3p in Osteosarcoma via Targeting EBF2.

Osteosarcoma (OS) is one of the most common primary malignant bone tumors in adolescents with a high mortality rate. MicroRNA (miRNA) is a kind of noncoding RNAs and has been proved to participate in many physiological processes. Many miRNAs have been reported to act as function regulators in OS. In our study, the miRNA and gene expression profiles of OS were downloaded from GEO Datasets and the differential expression analysis was performed using GEO2R. 58 up- and 126 downregulated miRNAs were found. In the three OS gene profiles, 125 up- and 27 downregulated genes were found to be differentially expressed in at least two profiles. The miRNA-mRNA networks were constructed to predict the potential target genes of 10 most up- and downregulated miRNA. Venn analysis was used to detect the coexpressed differentially expressed genes (DEGs). EBF2, one of the upregulated DEGs, was also a potential target gene of miR-182-3p. Knockdown and overexpression of miR-182-3p resulted in overexpression and downexpression of EBF2 separately. Luciferase reporter gene experiment further verified the binding site of miR-182-3p and EBF2. CCK8 assay showed that miR-182-3p knockdown can further enhance the proliferation activity of OS cells, while overexpressing miR-182-3p can inhibit the proliferation activity of OS cells. Our research indicated that downexpression of miR-182-3p in OS cells results in overexpression of EBF2 and promotes the progression of OS.

Chlorogenic acid inhibits osteosarcoma carcinogenesis via suppressing the STAT3/Snail pathway.

Chlorogenic acid (CA) is a polyphenol compound that possesses anticancer effects on several types of tumors. However, there are few previous studies concerning the protective effects of CA on osteosarcoma. The current study aimed to examine the toxicity of CA to osteosarcoma cells and to explore the potential mechanisms. Cell growth was evaluated using cell counting kit-8 assay and Western blot analysis of proliferating cell nuclear antigen (PCNA). Apoptosis was assessed by flow cytometry analysis using flow cytometry and caspase-3/7 activity assay. The expression changes of the signal transducer and activator of transcription 3 (STAT3)/Snail pathway were detected by Western blot analysis. We found that CA dose-dependently inhibited cell viability and PCNA expression in osteosarcoma cells. Meanwhile, CA treatment increased the apoptotic rate and caspase-3/7 activity in osteosarcoma cells in a concentration-dependent manner. We found that CA concentration-dependently inhibited the activation of the STAT3/Snail pathway in osteosarcoma cells. Inhibition of the STAT3/Snail pathway by si-STAT3 retarded the growth and induced apoptosis of osteosarcoma cells. Mechanistically, activation of the STAT3/Snail pathway by pcDNA-STAT3 reversed the effects of CA on osteosarcoma cell growth and apoptosis. In conclusion, CA inhibited osteosarcoma carcinogenesis by suppressing osteosarcoma cell growth and inducing apoptosis, which was involved in inactivation of the STAT3/Snail pathway. Therefore, our study suggested that CA might have good therapy prospects in osteosarcoma therapy.