Apoptosis Of Osteosarcoma Cells Research Articles

Cell migration induces apoptosis in osteosarcoma cell via inhibition of Wnt-β-catenin signaling pathway

The current design scheme on anti-cancer materials is mainly through tuning the mechanical properties of the materials to induce apoptosis in cancer cells, with the involvement of Rho/ROCK signaling pathway. We hypothesize that tuning the motility is another potential important approach to modifying the tumor microenvironment and inducing tumor apoptosis. To this aim, we have prepared RGD-modified substrates to regulate cell motility through modification of RGD with different concentrations, and systematically examined the effect of motility on the apoptosis of tumor cells, and the potential involvement of Wnt signaling pathway. Our studies indicated that RGD modification could be readily used to tune the motility of cancer cells. High RGD concentration significantly suppressed the migration of cancer cells, leading to significantly increased apoptosis rate, about three times of that of the unmodified samples. Western-blot analysis also showed that cell with low motility expressed more caspase-3 and PARP proteins. Further RNA sequence study strongly suggested that low motility inhibited the canonical Wnt signaling pathway, which in turn led to the activation of the mitochondria-associated caspase signaling pathway, and ultimately to the apoptosis of osteosarcoma cells. Activation of the Wnt-β-catenin pathway through HLY78 significantly suppressed the apoptosis of MG-63 cells, further suggesting the critical role of Wnt pathway in motility-regulated-apoptosis of tumor cells. Our findings shed insights to understand the underlying mechanisms that induced the tumor cell apoptosis, and might provide new strategy for designing the novel anti-tumor materials.

Comprehensive analysis of hypoxia-related genes for prognosis value, immune status, and therapy in osteosarcoma patients.

Osteosarcoma is a common malignant bone tumor in children and adolescents. The overall survival of osteosarcoma patients is remarkably poor. Herein, we sought to establish a reliable risk prognostic model to predict the prognosis of osteosarcoma patients. Patients ' RNA expression and corresponding clinical data were downloaded from the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) and Gene Expression Omnibus databases. A consensus clustering was conducted to uncover novel molecular subgroups based on 200 hypoxia-linked genes. A hypoxia-risk models were established by Cox regression analysis coupled with LASSO regression. Functional enrichment analysis, including Gene Ontology annotation and KEGG pathway analysis, were conducted to determine the associated mechanisms. Moreover, we explored relationships between the risk scores and age, gender, tumor microenvironment, and drug sensitivity by correlation analysis. We identified two molecular subgroups with significantly different survival rates and developed a risk model based on 12 genes. Survival analysis indicated that the high-risk osteosarcoma patients likely have a poor prognosis. The area under the curve (AUC) value showed the validity of our risk scoring model, and the nomogram indicates the model's reliability. High-risk patients had lower Tfh cell infiltration and a lower stromal score. We determined the abnormal expression of three prognostic genes in osteosarcoma cells. Sunitinib can promote osteosarcoma cell apoptosis with down-regulation of KCNJ3 expression. In summary, the constructed hypoxia-related risk score model can assist clinicians during clinical practice for osteosarcoma prognosis management. Immune and drug sensitivity analysis can provide essential insights into subsequent mechanisms. KCNJ3 may be a valuable prognostic marker for osteosarcoma development.

Role of let-7 family in the invasion and metastasis of osteosarcoma.

Role of let-7 family in the invasion and metastasis of osteosarcoma.

Isoquercitrin restrains the proliferation and promotes apoptosis of human osteosarcoma cells by inhibiting the Wnt/β-catenin pathway

Currently, chemotherapeutic drugs are widely used for the treatment of osteosarcoma. However, many of these drugs exhibit shortcomings such as poor efficacy, high toxicity, and tolerance. Isoquercitrin (ISO) is a traditional Chinese medicine that has been proved to exert good therapeutic effects on various tumors; however, its role in osteosarcoma has not been reported. Here, we observed that ISO exerted a marked inhibitory effect on the occurrence and development of osteosarcoma in a time- and dose-dependent manner. First, we determined that ISO significantly inhibited proliferation, induced EMT-related migration and invasion and induced apoptosis of osteosarcoma cells in vitro. Concurrently, we also observed that both β-catenin and its downstream genes (c-Myc, CyclinD1, and Survivin) were significantly down-regulated. To verify if the anti-tumor effect of ISO was related to the Wnt/β-catenin signaling pathway, we altered the protein expression level of β-catenin using recombinant lentivirus, then we observed that the effects of ISO on the proliferation, metastasis, and apoptosis of osteosarcoma cells were significantly reversed. Additionally, we used a nude mouse xenograft model and observed that ISO significantly inhibited the growth of osteosarcoma and improved the survival rate of the animal models. In conclusion, this study demonstrates that ISO can exert anti-tumor effects in part by inhibiting the Wnt/β-catenin signaling pathway, thus providing a new potential therapeutic strategy for the treatment of osteosarcoma.

Niclosamide is a potential candidate for the treatment of chemo-resistant osteosarcoma

Chemotherapy is the main treatment option for advanced osteosarcoma, which is the most common type of primary bone malignancy. However, patients develop resistance rapidly and many succumb to the disease. Niclosamide, an anthelmintic drug, has been recently identified to display potent and selective anti-cancer activity. In this work, we show that niclosamide at sub-micromolar concentrations inhibits proliferation and migration, and induces apoptosis in both parental and chemo-resistant osteosarcoma cells, with much less toxicity in normal osteoblastic cells. Interestingly, chemo-resistant osteosarcoma cells are more sensitive to niclosamide compared to parental cells. We further identify that inhibition of β-catenin is the underlying mechanism of niclosamide's action in osteosarcoma cells. In addition, we reveal that chemo-resistant osteosarcoma cells display increased β-catenin activity compared to parental cells, which might explain the hypersensitivity of chemo-resistant cells to niclosamide. Our work provides pre-clinical evidence that niclosamide can be repurposed for treating osteosarcoma. Our findings also suggest the therapeutic value of β-catenin to overcome osteosarcoma chemo-resistance.

IncRNA MALAT1 Regulates the Proliferation, Apoptosis, Migration, and Invasion of Osteosarcoma Cells by Targeting miR-873-5p/ROCK1.

The malignant bone tumor osteosarcoma (OS) was one of the most aggressive tumors. Despite breakthroughs in treatment options for OS recently, the survival rate of patients with metastasis or reoccurring disease has remained unchanged over the last 25 years, at around 20%. lncRNA expression dysregulation is linked to carcinogenesis, advancement, and metastasis. Additionally, the fundamental mechanism of lncRNAs in regulating OS cell biological activity and progression is still being investigated. The expression of miR-873-5p and MALAT1 were detected by quantitative real-time polymerase chain reaction (qRT-PCR) in OS. The relationship between the expression level of MALAT1 and the survival rate of OS individuals was evaluated by the Kaplan-Meier plotter. The tumor cell's capability of proliferation was determined using the CCK-8. Transwell was used to test the migratory and invasive properties of tumor cells. ROCK1 protein expression was analyzed by western blot, while qRT-PCR was used to detect ROCK1 mRNA expression. Targeted genes of MALAT1 or miR-873-5p were predicted by StarBase2.0. The target association among miR-873-5p and MALAT1 or ROCK1 was confirmed using the luciferase assay. The relationship between ROCK1 and MALAT1 or miR-873-5p expression in OS was investigated using Spearman's correlation analysis. MALAT1 was up-regulated and was linked to a lower survival rate of patients in OS. The malignant behaviors of cells were inhibited by down-regulated MALAT1 in vitro. Dual-luciferase gene experiments confirmed the presence of MALAT1/miR-873-5p/ROCK1 axis. The up-regulated miR-873-5p blocked the promoted effects of MALAT1 on cell behaviors. Over-expressed MALAT1 promoted the malignant behaviors of cells by miR-873-5p/ROCK1 axis in OS.

LINC00629 protects osteosarcoma cell from ER stress-induced apoptosis and facilitates tumour progression by elevating KLF4 stability

BackgroundEscaping from ER stress-induced apoptosis plays an important role in the progression of many tumours. However, its molecular mechanism in osteosarcoma remains incompletely understood.MethodsThe molecular mechanism was investigated using RNA sequencing, qRT–PCR and Western blot assays. The relationship between LINC00629 and KLF4 was investigated using RNA pulldown and ubiquitylation assays. The transcriptional regulation of laminin subunit alpha 4 (LAMA4) by KLF4 was identified using bioinformatic analysis, a luciferase assay, and a chromatin immunoprecipitation assay.ResultsHere, we demonstrated that LINC00629 was increased under ER stress treatment. Elevated LINC00629 inhibited ER stress-induced osteosarcoma cell apoptosis and promoted clonogenicity and migration in vitro and in vivo. Further mechanistic studies indicated that LINC00629 interacted with KLF4 and suppressed its degradation, which led to a KLF4 increase in osteosarcoma. In addition, we also found that KLF4 upregulated LAMA4 expression by directly binding to its promoter and that LINC00629 inhibited ER stress-induced apoptosis and facilitated osteosarcoma cell clonogenicity and metastasis by activating the KLF4-LAMA4 pathway.ConclusionCollectively, our data indicate that LINC00629 is a critical long noncoding RNA (lncRNA) induced by ER stress and plays an oncogenic role in osteosarcoma cell by activating the KLF4-LAMA4 axis.

The Impacts of Calcium Ions Substitution in Hydroxyapatite with Neodymium and Zinc on Biological Properties and Osteosarcoma Cells

Hydroxyapatite (HA) is one of the important biomaterials in the medical field, especially in bone treatment, because of its biological properties close to human bone. A simple co-precipitation technique was used to integrate neodymium and zinc into HA by adding neodymium nitrate and zinc nitrate as a source of substituted elements during synthesis through the wet precipitation method with controlled temperature and pH. Finally, substituted HA was sintered at 800°C after completing the biomaterial preparation. The resulting Nd-Zn/HA was globe-like with nanoparticle size. The Ca+Nd+Zn/P ratio was equal to 1.63, which is relatively close to the molar ratio of bone. Also, the ability of Nd-Zn/HA to cause apoptosis in osteosarcoma cells was discovered. The anti-tumor actions are amplified when increasing the concentration of substituted HA. Therefore, Nd-Zn/HA is a potentially effective biomaterial in osteosarcoma treatment. Meanwhile, it has antibacterial and fungicidal properties against Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus mutans, Escherichia coli, and Candida albicans—one of the important properties required in biomaterials to protect the part that is being treated after the biomaterial is implanted inside the body. The inhibition zone of Nd-Zn/HA ranged between (20-31)mm, much higher than gentamicin and nystatin.

Caffeic Acid Inhibits Tumour Mass Formation in MG-63 Cells-induced Nude Mice

BACKGROUND: Formation of tumour mass is one symptom of osteosarcoma development. Caffeic acid has been known to provide effective treatment but has less side effect for some cancer therapy. Studies reported that caffeic acid might promote apoptosis in MG-63 osteosarcoma cells, however, the effect of caffeic acid treatment in preventing tumour mass formation has not been well elucidated, especially in MG-63 cells-induced nude mice in vivo.METHODS: MG-63 cells were pre-treated with 0, 1, or 10 µg/mL caffeic acid, and 6 hours after pre-treatment, MG-63 cells were injected into subcutaneous space of mice to induce osteosarcoma. Another model was also created by subcutaneously injecting MG-63 cells to the back of mice, and after 48 days, the visible tumour mass was injected intra-tumour with 0 or 10 µg/mL caffeic acid every 7 days for 6 times. After 90 days, mice were anaesthetised, and the nodule pictures were taken for observation and measurement. RESULTS: In pre-treated MG-63 cells-induced mice, volumes of the mass decreased in reverse with the dose of caffeic acid given. Ten µg/mL caffeic acid pre-treatment was able to significantly lower the mass volume compared to the untreated (p<0.05). Meanwhile, the intra-tumour treatment of 10 µg/mL caffeic acid, even though not significant, was able to inhibit tumour mass formation.CONCLUSION: Results of caffeic acid pre-treatment and caffeic acid treatment in tumour mass of mice show that caffeic acid is able to inhibit the MG-63 cells formation. This suggests that caffeic acid can be a potential anti-cancer agent.KEYWORDS: caffeic acid, osteosarcoma, MG-63 cells, tumour mass

Caffeic Acid Induces Apoptosis in MG-63 Osteosarcoma Cells via Protein Kinase C Delta (PKCδ) Translocation and Mitochondrial Membrane Potential Reduction

BACKGROUND: Caffeic acid has been reported to activate caspases in MG-63 osteosarcoma cells, which can lead to apoptosis via both extrinsic and intrinsic apoptotic pathways. Translocation of protein kinase C delta (PKCδ), which reduces mitochondrial membrane potential (ΔΨm), is involved in apoptosis. The role of PKCδ translocation and ΔΨm alteration in caffeic acid-induced MG-63 cell apoptosis are largely unknown. Present study investigated the effect of caffeic acid on PKCδ translocation and ΔΨm in MG-63 cells.METHODS: MG-63 cells were cultured and starved, followed by pretreatment with or without Z-VAD-FMK and treatment with or without 10 μg/mL caffeic acid. MG-63 cells were collected, lysed, and processed to obtain cytosolic and mitochondrial fractions. Each fraction was subjected to immunoblotting analysis by using anti-PKCδ antibody. Mitochondrial membrane potential (ΔΨm) was measured using flow cytometry.RESULTS: Cytosolic PKCδ levels were higher than mitochondrial PKCδ levels in untreated and 1 h caffeic acid treatment groups. Inversely, cytosolic PKCδ levels were lower than the mitochondrial PKCδ levels after 6 and 12 h caffeic acid treatment. By Z-VAD-FMK pretreatment, cytosolic PKCδ levels were higher than mitochondrial PKCδ after 6 and 12 h caffeic acid treatment. After 6 h treatment with caffeic acid, ΔΨm was slightly shifted. More shifting occurred in MG-63 cells treated with caffeic acid for 12 h. The ΔΨm shifting was inhibited by Z-VAD-FMK pretreatment.CONCLUSION: Caffeic acid could trigger apoptosis of MG-63 osteosarcoma cells by inducing PKCδ translocation to mitochondria and reducing ΔΨm, which might cause MMP.KEYWORDS: caffeic acid, MG-63, osteosarcoma, PKCδ, mitochondrial membrane potential, mitochondrial membrane permeabilization, Z-VAD-FMK

Circ_0000253 promotes the progression of osteosarcoma via the miR-1236-3p/SP1 axis.

Circular RNAs (circRNAs) play important roles in modulating tumour progression. This study investigated the role of circ_0000253 in osteosarcoma (OS). We downloaded the chip dataset GSE140256 from the Gene Expression Omnibus database and the circRNAs differentially expressed in OS tissue and normal tissue samples were analysed. Quantitative real-time PCR (qRT-PCR) was carried out to examine circ_0000253 expression in OS tissues and cells. Cell counting kit-8, BrdU and flow cytometry assays were performed to verify the effects of circ_0000253 on OS cell growth and apoptosis. Bioinformatics analysis was conducted to predict, and RNA immunoprecipitation assay and dual-luciferase reporter gene assay were performed to verify the targeted relationships of miR-1236-3p with circ_0000253 and Sp1 transcription factor (SP1) mRNA 3'UTR. The effects of miR-1236-3p and circ_0000253 on SP1 expression in OS cells were detected through Western blot. Circ_0000253 was upregulated in OS tissues and cell lines. Circ_0000253 overexpression facilitated OS cell growth and suppressed apoptosis, whereas knocking down circ_0000253 inhibited OS cell growth and facilitated apoptosis. Circ_0000253 targeted miR-1236-3p directly and negatively modulated its expression. SP1 was miR-1236-3p's target gene and positively regulated by circ_0000253. Circ_0000253 promotes OS cell proliferation and suppresses cell apoptosis via regulating the miR-1236-3p/SP1 molecular axis.

Dioscin induces osteosarcoma cell apoptosis by upregulating ROS-mediated P38 MAPK signaling.

Osteosarcoma is the most common primary malignant bone tumor in children and adolescents. Many patients with osteosarcoma readily develop resistance to chemotherapy and have an extremely dismal prognosis. Dioscin, a saponin, is known to exhibit potent anticancer activities and induce cellular death of a variety of cancer types. However, the inhibitory effect of dioscin on osteosarcoma cells and its underlying mechanisms have not been fully elucidated. We investigated the responses of human U2-OS and MG63 osteosarcoma cells to dioscin with regard to proliferation, apoptosis, migration, and invasion, and studied the effect of dioscin on MAPK-related proteins by western blot analysis assays. Dioscin inhibited osteosarcoma cell proliferation, migration, and invasion. Moreover, it induced osteosarcoma cell apoptosis via reactive oxygen species (ROS)-dependent apoptotic signaling. N-acetylcysteine, a reactive oxygen species inhibitor, suppressed dioscin-induced apoptosis, indicating that ROS play an essential role in dioscin-induced apoptosis. Western blot analysis assays showed that p38 MAPK was upregulated after dioscin treatment, and that dioscin induced apoptosis by upregulating ROS-mediated p38 MAPK signaling. Our study suggests that dioscin possesses antitumor activities against human osteosarcoma cells, inhibits osteosarcoma cell proliferation, migration and invasion, and induces osteosarcoma cell apoptosis through upregulating ROS-mediated p38 MAPK signaling. This study may provide a new therapeutic strategy and potential clinical applications for the treatment of osteosarcoma.

ADCK1 is a potential therapeutic target of osteosarcoma

We here showed that ADCK1 (AarF domain-containing kinase 1), a mitochondrial protein, is upregulated in human osteosarcoma (OS) tissues and OS cells. In primary and established OS cells, ADCK1 shRNA or CRISPR/Cas9-induced ADCK1 knockout (KO) remarkably inhibited cell viability, proliferation and migration, and provoked apoptosis activation. Conversely, ectopic ADCK1 overexpression exerted pro-cancerous activity by promoting OS cell proliferation and migration. ADCK1 depletion disrupted mitochondrial functions in OS cells and induced mitochondrial membrane potential reduction, ATP depletion, reactive oxygen species production. Significantly, ADCK1 silencing augmented doxorubicin-induced apoptosis in primary OS cells. mTOR activation is important for ADCK1 expression in OS cells. The mTOR inhibitors, rapamycin and AZD2014, as well as mTOR shRNA, potently decreased ADCK1 expression in primary OS cells. In nude mice, the growth of subcutaneous pOS-1 xenografts was largely inhibited when bearing ADCK1 shRNA or ADCK1 KO construct. Moreover, ADCK1 KO largely inhibited pOS-1 xenograft in situ growth in proximal tibia of nude mice. ADCK1 depletion, apoptosis activation and ATP reduction were detected in pOS-1 xenografts bearing ADCK1 shRNA or ADCK1 KO construct. Together, the mitochondrial protein ADCK1 is required for OS cell growth and is a novel therapeutic target of OS.

Effects of miR-32 on Proliferation, Apoptosis, Invasion and Migration of Osteosarcoma Cells by Targeting PTEN

Objective: To observe the impact of miR-32 on the proliferation and apoptosis of osteosarcoma U2OS cell line, and to explore its possible causative roles. Methods: Detection of miR-32 expression in carcinoma tissues and normal adjacent tissues of 44 osteosarcoma patients was achieved employing QRT-PCR technique. The liposome transfection technique was utilized to knock down the miR-32 of osteosarcoma U2OS cells and determine osteosarcoma cell proliferation, apoptosis migration ae well as invasion. Results: MiR-32 expressions in cancer tissues of osteosarcoma patients were markedly higher than that of adjacent tissues. Moreover, miR-32 expression further decreased as the clinical stage of the tumor progressed. MiR-32 knockdown could remarkably inhibit the formation of osteosarcoma cell clones, proliferation,migration and invasion level, whereas promote cancer cell apoptosis. Meanwhile, miR-32 knockdown can noteworthily reduce the level of oxidative stress and autophagy in osteosarcoma cells. Mechanistically, miR-32 can target and inhibit PTEN protein, knocking down miR-32 can activate PTEN/mTOR signaling pathway. In contrast, inhibiting PTEN protein expression can counteract the antitumor effect caused by miR-32 knockdown. Subcutaneous tumorigenesis experiments further confirmed the anti-osteosarcoma cell growth effect of miR-32. Conclusion: MiR-32 expression is apparently increased in cancer tissues of osteosarcoma patients. MiR-32 knockdown can suppress the proliferation of osteosarcoma cells and promote their apoptosis by targeting activation of PTEN-mediated mTOR activation.

Circ-NT5C2 stimulates FZD4 expression to promote the malignant progression of osteosarcoma by targeting miR-488-3p

BackgroundCirc-NT5C2 has been confirmed to be highly expressed and associated to the progression of osteosarcoma (OS). However, the behind mechanism of circ-NT5C2 involvement in OS remains unclear.MethodsThe expression of circ-NT5C2, miR-488-3p and FZD4 was measured by quantitative real-time PCR, and the protein expression of E-cadherin, N-cadherin and FZD4 was detected by western blot. Cell counting kit 8 assay, colony formation assay and 5-ethynyl-2-deoxyuridine assay were performed to assess the cell proliferation. The cell apoptosis was measured by flow cytometry and Caspase3/Caspase9 Activity Assay Kits. Cell migration and invasion were detected by transwell assay. Dual-luciferase reporter assay and RIP assay were carried out to determine the binding relation among circ-NT5C2, miR-488-3p and FZD4. Animal experiment and immunohistochemistry analysis were conducted to explore the role of circ-NT5C2 in tumor growth in vivo.ResultsComparing with controls, the expression of circ-NT5C2 and FZD4 was upregulated and miR-488-3p expression was downregulated in OS tumor tissues and cells. Circ-NT5C2 overexpression facilitated the cell proliferation and motility and induced cell apoptosis of OS cells, whereas circ-NT5C2 knockdown had the opposite effect. Besides, we also found and confirmed that circ-NT5C2 regulated cell malignant behaviors via modulating miR-488-3p/FZD4 axis in OS. Moreover, circ-NT5C2 silencing repressed the growth of xenografts in vivo.ConclusionCirc-NT5C2 upregulated FZD4 expression via sponging miR-488-3p, thus facilitating cell malignant behaviors in OS.

Curculigoside Represses the Proliferation and Metastasis of Osteosarcoma via the JAK/STAT and NF-κB Signaling Pathways.

Curculigoside (Cur) is a natural component from Curculigo orchioides Gaertn, with various bioactivities. The function of Cur in the nervous system and osteoarthritis has been reported. However, its role in osteosarcoma (OS) needs to be investigated. Hence, we focus on probing the impact of Cur on OS. In vitro, cell counting kit 8 (CCK-8), flow cytometry and Transwell assay were used to investigate the effects of Cur on OS cell proliferation, apoptosis, migration and invasion. In vivo, we developed a xenograft model to figure out the effect of Cur on tumor growth in nude mice. Western blotting (WB) was conducted to compare the levels of Cur on apoptosis-related proteins (C-caspase-3, Bax, and Bcl-2), epithelial-mesenchymal transition (EMT)-related proteins (N-cadherin, Snail, and E-cadherin) and the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) and nuclear factor-κB (NF-κB) pathways in vitro and in vivo. In-vitro data testified that Cur treatment markedly hampered OS cells' growth, migration and invasion and intensified their apoptosis compared to that of the control group. In vivo, Cur treatment notably hampered the growth of OS tumors in mice. In addition, both in vitro and in vivo experiments demonstrated that the phosphorylation of JAK2, STAT3, and NF-κB were inhibited through Cur treatment. Furthermore, the inhibition of Cur in OS cells was demonstrated by up-regulating the expression of JAK/STAT and NF-κB pathways protein levels. In summary, the data suggest that Cur curbs OS growth by down-regulating the JAK/STAT and NF-κB pathways, which is an underlying therapeutic option for OS treatment.

ZCCHC12 promotes the progression of osteosarcoma via PI3K/AKT pathway.

Researchers have reported that zinc finger CCHC domain containing 12 gene (ZCCHC12) plays a role in the progression and tumorigenesis of papillary thyroid cancer. However, the biological role of ZCCHC12 in osteosarcoma (OS) remains unknown. ZCCHC12 was highly upregulated in OS cell lines according to our present study. Also, our subsequent assays demonstrated that ZCCHC12 enhanced the proliferation, tumor growth and migration of OS cells. Moreover, the epithelial-mesenchymal transition (EMT) of OS cells was also promoted by ZCCHC12. In addition, downregulation of ZCCHC12 induced apoptosis and S-phase arrest in OS cells. Then, our study indicated that ZCCHC12 exerts its oncogenic function in OS cells by activating the PI3K/AKT pathway. Inhibition of the PI3K/AKT pathway greatly limits the oncogenic function of ZCCHC12 in OS cells. Also, overexpression of ZCCHC12 promotes tumor growth in vivo. Altogether, our study suggests ZCCHC12 promotes OS cells progression by activating the PI3K/AKT pathway. The ZCCHC12 gene may be a novel diagnostic and therapeutic target for OS.

Circ_0136666 aggravates osteosarcoma development through mediating miR-1244/CEP55 axis

BackgroundAccumulating articles demonstrate that circular RNAs play pivotal functions in tumorigenesis. However, the working mechanism of circ_0136666 in osteosarcoma (OS) progression remains to be further clarified.MethodsReal time-quantitative polymerase chain reaction and western blot assay were applied to determine RNA and protein expression, respectively. Cell proliferation was assessed by 5-Ethynyl-2′-deoxyuridine assay and colony formation assay. Transwell assays were carried out to assess cell migration and invasion abilities. Flow cytometry was performed to analyze cell apoptosis. Cell glycolysis was evaluated by analyzing the uptake of glucose and the production of lactate using the corresponding kits. Dual-luciferase reporter assay and biotinylated RNA-pull down assay were performed to confirm the target interaction between microRNA-1244 (miR-1244) and circ_0136666 or centrosomal protein 55 (CEP55). Xenograft tumor model was utilized to explore the role of circ_0136666 in tumor growth in vivo.ResultsCirc_0136666 expression was prominently elevated in OS tissues and cell lines. Circ_0136666 absence restrained the proliferation, migration, invasion and glycolytic metabolism and promoted the apoptosis of OS cells. Circ_0136666 negatively regulated miR-1244 expression by binding to it in OS cells. MiR-1244 overexpression suppressed the malignant behaviors of OS cells. CEP55 was a target of miR-1244 in OS cells. Circ_0136666 positively regulated CEP55 expression partly by sequestering miR-1244 in OS cells. CEP55 overexpression largely reversed circ_0136666 silencing-mediated influences in OS cells. Circ_0136666 silencing significantly suppressed tumor growth in vivo.ConclusionCirc_0136666 silencing inhibited OS progression partly by targeting miR-1244/CEP55 signaling. Silencing circ_0136666 and CEP55 or restoring miR-1244 level might be a potential therapeutic strategy for OS.

Caffeic Acid Induces Intrinsic Apoptotic Pathway in MG-63 Osteosarcoma Cells Through Bid Truncation and Cytochrome c Release

BACKGROUND: Caffeic acid has been reported to induce apoptosis in MG-63 osteosarcoma cells via caspases activation. However, apoptotic pathway that is involved in the caffeic acid-induced apoptosis is still unclear. Present study aimed to investigate the role of cytochrome c (Cyt c) release and BH3-interacting death (Bid) activation in caffeic acid-induced apoptosis in MG-63 osteosarcoma cells.METHODS: MG-63 cells were cultured, pretreated with/without Z-VAD FMK and treated with/without 10 μg/mL caffeic acid. Treated MG-63 cells were then lysed, homogenized, and processed further to prepare cell lysate and mitochondrial fraction. Immunoblotting method was used to measure the amount of Bid and truncated Bid (t-Bid) as well as mitochondrial and cytosolic Cyt c.RESULTS: The amount of Bid and mitochondrial Cyt c in MG-63 cells decreased in a time-dependent manner, while the amount of t-Bid and cytosolic Cyt c increased in a time-dependent manner. By pretreatment of 100 μM Z-VAD-FMK for 2 h, the amount of Bid and mitochondrial Cyt c was significantly higher, while the amount of t-Bid and cytosolic Cyt c was significantly lower after caffeic acid treatment for 6 and 12 h compared to MG-63 cells that were not pretreated.CONCLUSION: Caffeic acid could induce Cyt c release through the activation of Bid in MG-63 osteosarcoma cells.KEYWORDS: caffeic acid, osteosarcoma, MG-63 cells, Bid, t-Bid, cytochrome c, Z-VAD-FMK

Retraction: MicroRNA-182 downregulates Wnt/β-catenin signaling, inhibits proliferation, and promotes apoptosis in human osteosarcoma cells by targeting HOXA9.

[This retracts the article DOI: 10.18632/oncotarget.21167.].