Osteosarcoma Cell Proliferation Research Articles

Emodin induces osteosarcoma cell apoptosis by promoting ATM protein cleavage

Purpose: To investigate the effect of emodin on osteosarcoma cell proliferation and apoptosis.
 Methods: The osteosarcoma cell proliferation ability was determined by CCK-8, apoptosis level and cell cycle were determined via flow cytometry. Honechst staining was used to determine the ratio of nuclear pyknosis, Western blotting was used to determine the expression of AKT, p-AKT and caspase-3 precursor protein in each group of osteosarcoma cells.
 Results: Emodin significantly inhibited the MG-63 cell proliferation and promoted the apoptosis of osteosarcoma cells in a dose-dependent manner (p < 0.05). It further blocked osteosarcoma cells in G1/G0 phase and decreased the expression of AKT, p-AKT, and caspase-3 (p < 0.05).
 Conclusion: Emodin inhibits osteosarcoma cell growth by inhibiting ATM protein cleavage. There is a need to carry out further investigation of the effect of emodin on osteosarcoma cells using animal models in order to ascertain its potential in the management of osteosarcoma.

Long Noncoding RNA PCGEM1 Facilitates Tumor Growth and Metastasis of Osteosarcoma by Sponging miR-433-3p and Targeting OMA1.

Osteosarcoma (OS) is regarded as one of the most common malignant bone tumors, mainly occurring in children and adolescents with high mortality. The dysregulation of lncRNAs is reported to regulate tumor development and be closely related to patient prognosis. Nevertheless, the role of long noncoding RNAs (lncRNAs) prostate-specific transcript 1 (PCGEM1) in OS remains uncharacterized. The current study aimed to explore the role of PCGEM1 in OS. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed to examine the expression of PCGEM1 in OS cell lines. CCK-8, colony formation, Transwell, and western blotting analyses were applied to measure OS cell viability, proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) after PCGEM1 downregulation. Nuclear-cytoplasmic fractionation, RNA pulldown, RNA immunoprecipitation (RIP), luciferase reporter assays were performed to verify the relationship among PCGEM1, miR-433-3p. and OMA1 in OS. The xenograft tumor models were established to evaluate the effect of PCGEM1 on tumor growth of OS. In this study, we discovered that PCGEM1 knockdown inhibited cell proliferation, migration, invasion and EMT in OS (P < 0.05). Additionally, PCGEM1 directly bound to miR-433-3p (P < 0.01). OMA1 was confirmed to be a target gene of miR-433-3p (P < 0.05), positively regulated by PCGEM1 but negatively regulated by miR-433-3p. Rescue assays further verified that overexpression of OMA1 reversed the PCGEM1 knockdown-mediated inhibitory effect on the malignant phenotype in OS cells (P < 0.05). Moreover, knockdown of PCGEM1 inhibited tumor growth and metastasis in vivo (P < 0.05). Overall, PCGEM1 mediated tumor growth and metastasis of OS by sponging miR-433-3p and regulating OMA1, which might provide an innovative strategy for OS diagnosis or treatment.

ITGB3 promotes cisplatin resistance in osteosarcoma tumors.

Osteosarcoma is the most malignant and common primary bone tumor with a high rate of recurrence that mainly occurs in children and young adults. Therefore, it is vital to facilitate the development of novel effective therapeutic means and improve the overall prognosis of osteosarcoma patients via a deeper understanding of the mechanisms of chemoresistance in osteosarcoma progression. In this research, the relationship between ITGB3 and the clinical characteristics of patients was detected through analysis of publicly available clinical datasets. The expression of ITGB3 was analysis in collected human osteosarcoma tissues. In addition, the potential functions of ITGB3 in the cisplatin resistance of osteosarcoma cells were investigated in vitro and in tumor xenotransplantation. Finally, the molecular mechanism of ITGB3 in the progression and recurrence of osteosarcoma were explored via transcriptome analysis. ITGB3 was identified as a potential regulator of tumorigenicity and cisplatin resistance in relapsed osteosarcoma. Furthermore, the decreased osteosarcoma cell proliferation and migration ability in ITGB3 knockout osteosarcoma cells were related to increased apoptosis and slowing cell cycle progression. In addition, ITGB3 had a positive correlation with cisplatin resistance in cells and tumor xenografts in mice. Accordingly, ITGB3 performed the functions of proliferation and cisplatin resistance in osteosarcoma through the MAPK and VEGF signaling pathways. Our results will contribute to a better understanding of the function and mechanism of ITGB3 in osteosarcoma cisplatin resistance and provide a novel therapeutic target to decrease cisplatin resistance and tumor recurrence in osteosarcoma patients.

Alizarin as a potential protector of proteins against damage caused by hydroperoxyl radical

Alizarin is a natural anthraquinone molecule with moderate antioxidative capacity. Some earlier investigations indicated that it can inhibit osteosarcoma and breast carcinoma cell proliferation by inhibiting of phosphorylation process of ERK protein (extracellular signal-regulated kinases). Several mechanisms of deactivation of one of the most reactive oxygen species, hydroperoxyl radical, by alizarin are estimated: hydrogen atom abstraction (HAA), radical adduct formation (RAF), and single electron transfer (SET). The plausibility of those mechanisms is estimated using density functional theory. The obtained results indicated HAA as the only thermodynamically plausible mechanism. For that purpose, two possible mechanistic pathways for hydrogen atom abstraction are studied in detail: hydrogen atom transfer (HAT) and proton-coupled electron transfer (PCET). Water and benzene are used as models of solvents with opposite polarity. To examine the difference between HAT and PCET is used kinetical approach based on the Transition state theory (TST) and determined rate constants (k). Important data used for a distinction between HAT and PCET mechanisms are obtained by applying the Quantum Theory of Atoms in Molecules (QTAIM), and by the analysis of single occupied molecular orbitals (SOMOs) in transition states for two examined mechanisms. The molecular docking analysis and molecular dynamic are used to predict the most probable positions of binding of alizarin to the sequence of ApoB-100 protein, a protein component of plasma low-density lipoproteins (LDL). It is found that alizarin links the nitrated polypeptide forming the π-π interactions with the amino acids Phenylalanine and Nitrotyrosine. The ability of alizarin to scavenge hydroperoxyl radical when it is in a sandwich structure between the polypeptide and radical species, as the operative reaction mechanism, is not significantly changed concerning its antioxidant capacity in the absence of polypeptide. Therefore, alizarin can protect the polypeptide from harmful hydroperoxyl radical attack, positioning itself between the polypeptide chain and the reactive oxygen species.

Development of an osteosarcoma model with MYCN amplification and TP53 mutation in hiPS cell-derived neural crest cells.

Mesenchymal stem cell- or osteoblast-derived osteosarcoma is the most common malignant bone tumor. Its highly metastatic malignant phenotypes, which are often associated with a poor prognosis, have been correlated with the modulation of TP53- and cell-cycle-related pathways. MYC, which regulates the transcription of cell-cycle modulating genes, is used as a representative prognostic marker for osteosarcoma. Another member of the MYC oncoprotein family, MYCN, is highly expressed in a subset of osteosarcoma, however its roles in osteosarcoma have not been fully elucidated. Here, we attempted to create an in vitro tumorigenesis model using hiPSC-derived neural crest cells, which are precursors of mesenchymal stem cells, by overexpressing MYCN on a heterozygous TP53 hotspot mutation (c.733G>A; p.G245S) background. MYCN-expressing TP53 mutated transformed clones were isolated by soft agar colony formation, and administered subcutaneously into the periadrenal adipose tissue of immunodeficient mice, resulting in the development of chondroblastic osteosarcoma. MYCN suppression decreased the proliferation of MYCN-induced osteosarcoma cells, suggesting MYCN as a potential target for a subset of osteosarcoma treatment. Further, comprehensive analysis of gene expression and exome sequencing of MYCN-induced clones indicated osteosarcoma-specific molecular features, such as the activation of TGF-β signaling and DNA copy number amplification of GLI1. The model of MYCN-expressing chondroblastic osteosarcoma was developed from hiPSC-derived neural crest cells, providing a useful tool for the development of new tumor models using hiPSC-derived progenitor cells with gene modifications and in vitro transformation.

Inhibition of Macropinocytosis Enhances the Sensitivity of Osteosarcoma Cells to Benzethonium Chloride.

Osteosarcoma (OS) is a primary malignant tumor of bone. Chemotherapy is one of the crucial approaches to prevent its metastasis and improve prognosis. Despite continuous improvements in the clinical treatment of OS, tumor resistance and metastasis remain dominant clinical challenges. Macropinocytosis, a form of non-selective nutrient endocytosis, has received increasing attention as a novel target for cancer therapy, yet its role in OS cells remains obscure. Benzethonium chloride (BZN) is an FDA-approved antiseptic and bactericide with broad-spectrum anticancer effects. Here, we described that BZN suppressed the proliferation, migration, and invasion of OS cells in vitro and in vivo, but simultaneously promoted the massive accumulation of cytoplasmic vacuoles as well. Mechanistically, BZN repressed the ERK1/2 signaling pathway, and the ERK1/2 activator partially neutralized the inhibitory effect of BZN on OS cells. Subsequently, we demonstrated that vacuoles originated from macropinocytosis and indicated that OS cells might employ macropinocytosis as a compensatory survival mechanism in response to BZN. Remarkably, macropinocytosis inhibitors enhanced the anti-OS effect of BZN in vitro and in vivo. In conclusion, our results suggest that BZN may inhibit OS cells by repressing the ERK1/2 signaling pathway and propose a potential strategy to enhance the BZN-induced inhibitory effect by suppressing macropinocytosis.

Genipin inhibits the development of osteosarcoma through PI3K/AKT signaling pathway.

Osteosarcoma is a highly invasive and early metastatic tumor. At present, the toxic and side effects of chemotherapy affect the quality of life of cancer patients to varying degrees. Genipin is an extract of the natural medicine gardenia with various pharmacological activities. The purpose of this study was to investigate the effect of Genipin on osteosarcoma and its potential mechanism of action. Crystal violet staining, MTT assay and colony formation assay were used to detect the effect of genipin on the proliferation of osteosarcoma. The effects of vitexin on migration and invasion of osteosarcoma were detected by scratch healing assay and transwell assay. Hoechst staining and flow cytometry were used to detect the effect of genipin on apoptosis of osteosarcoma cells. The expression of related proteins was detected by Western blot. An orthotopic tumorigenic animal model was used to verify the effect of genipin on osteosarcoma in vivo. The results of crystal violet staining, MTT method and colony formation method proved that genipin significantly inhibited the proliferation of osteosarcoma cells. The results of the scratch healing assay and transwell assay showed that gen significantly inhibited the migration and invasion of osteosarcoma cells. The results of Hoechst staining and flow cytometry showed that genipin significantly promoted the apoptosis of osteosarcoma cells. The results of animal experiments show that genipin has the same anti-tumor effect in vivo. Genipin may inhibit the growth of osteosarcoma through PI3K/AKT signaling. Genipin can inhibit the growth of human osteosarcoma cells, and its mechanism may be related to the regulation of PI3K/AKT signaling pathway.

2-Hydroxy-3-methylanthraquinone inhibits homologous recombination repair in osteosarcoma through the MYC-CHK1-RAD51 axis

BackgroundOsteosarcoma is a malignant bone tumor that usually affects adolescents aged 15–19 y. The DNA damage response (DDR) is significantly enhanced in osteosarcoma, impairing the effect of systemic chemotherapy. Targeting the DDR process was considered a feasible strategy benefitting osteosarcoma patients. However, the clinical application of DDR inhibitors is not impressive because of their side effects. Chinese herbal medicines with high anti-tumor effects and low toxicity in the human body have gradually gained attention. 2-Hydroxy-3-methylanthraquinone (HMA), a Chinese medicine monomer found in the extract of Oldenlandia diffusa, exerts significant inhibitory effects on various tumors. However, its anti-osteosarcoma effects and defined molecular mechanisms have not been reported.MethodsAfter HMA treatment, the proliferation and metastasis capacity of osteosarcoma cells was detected by CCK-8, colony formation, transwell assays and Annexin V-fluorescein isothiocyanate/propidium iodide staining. RNA-sequence, plasmid infection, RNA interference, Western blotting and immunofluorescence assay were used to investigate the molecular mechanism and effects of HMA inhibiting osteosarcoma. Rescue assay and CHIP assay was used to further verified the relationship between MYC, CHK1 and RAD51.ResultsHMA regulate MYC to inhibit osteosarcoma proliferation and DNA damage repair through PI3K/AKT signaling pathway. The results of RNA-seq, IHC, Western boltting etc. showed relationship between MYC, CHK1 and RAD51. Rescue assay and CHIP assay further verified HMA can impair homologous recombination repair through the MYC-CHK1-RAD51 pathway.ConclusionHMA significantly inhibits osteosarcoma proliferation and homologous recombination repair through the MYC-CHK1-RAD51 pathway, which is mediated by the PI3K-AKT signaling pathway. This study investigated the exact mechanism of the anti-osteosarcoma effect of HMA and provided a potential feasible strategy for the clinical treatment of human osteosarcoma.Graphical

The Biocompatibility and Antibacterial Properties of the CNTs-Doped Magnesium Based Composite Implants in a Long-Term Biodegradation Process

The aim of this paper is to increase a new biodegradable implant material’s biodegradability, biocompatibility, and osteoinductivity in the long-term degradation process, as well as its antibacterial properties, novel carbon nanotubes (CNTs) with or without Cu element were doped into calcium phosphate (CaP)–chitosan (CS) layers and then fabricated to obtain the magnesium (Mg) matrix composites. In this paper, we investigated the influences of the CNTs-CaP-CS/Mg composites on proliferation and osteogenic differentiation of human osteosarcoma cell (SaOS-2) and human bone marrow mesenchymal stem cells (hBMSCs). Furthermore, the Cu/CNTs-CaP-CS/Mg was prepared to improve the bioactivity and antibacterial activity of the composites. The results indicated that CNTs-CaP-CS/Mg composites were suitable for proliferation and differentiation of SaOS-2 cells. Stimulated by the CNTs-CaP-CS/Mg extracts, the ALP expression of hBMSCs increased in the first 16 days and the mineralization ability of hBMSCs was highly expressed throughout the whole process which might be through the Erk1/2 signaling pathway. After CNTs-loaded Cu element, the bioactivity of the coating was satisfactory. Moreover, this new implant exhibited excellent antibacterial properties for Escherichia coli (E. coli) and Staphylococcus albus (S. albus). Collectively, these data suggest that the CNTs-CaP-CS/Mg and Cu/CNTs-CaP-CS/Mg might be potentially applied as bone implants for future clinical use.

Nuclear receptor modulators inhibit osteosarcoma cell proliferation and tumour growth by regulating the mTOR signaling pathway

Osteosarcoma is the most common primary malignant bone tumour in children and adolescents. Chemoresistance leads to poor responses to conventional therapy in patients with osteosarcoma. The discovery of novel effective therapeutic targets and drugs is still the main focus of osteosarcoma research. Nuclear receptors (NRs) have shown substantial promise as novel therapeutic targets for various cancers. In the present study, we performed a drug screen using 29 chemicals that specifically target 17 NRs in several different human osteosarcoma and osteoblast cell lines. The retinoic acid receptor beta (RARb) antagonist LE135, peroxisome proliferator activated receptor gamma (PPARg) antagonist T0070907, liver X receptor (LXR) agonist T0901317 and Rev-Erba agonist SR9011 significantly inhibited the proliferation of malignant osteosarcoma cells (U2OS, HOS-MNNG and Saos-2 cells) but did not inhibit the growth of normal osteoblasts. The effects of these NR modulators on osteosarcoma cells occurred in a dose-dependent manner and were not observed in NR-knockout osteosarcoma cells. These NR modulators also significantly inhibited osteosarcoma growth in vivo and enhanced the antitumour effect of doxorubicin (DOX). Transcriptomic and immunoblotting results showed that these NR modulators may inhibit the growth of osteosarcoma cells by regulating the PI3K/AKT/mTOR and ERK/mTOR pathways. DDIT4, which blocks mTOR activation, was identified as one of the common downstream target genes of these NRs. DDIT4 knockout significantly attenuated the inhibitory effects of these NR modulators on osteosarcoma cell growth. Together, our results revealed that modulators of RARb, PPARg, LXRs and Rev-Erba inhibit osteosarcoma growth both in vitro and in vivo through the mTOR signaling pathway, suggesting that treatment with these NR modulators is a novel potential therapeutic strategy.

MiR-125b-5p inhibits proliferation and migration of osteosarcoma cells by negatively regulating RAB3D expression

To investigate the inhibitory effect of miR-125b-5p on proliferation and migration of osteosarcoma and the role of RAB3D in mediating this effect. The expression level of miR-125b-5p was detected by qRT-PCR in a normal bone cell line (hFOB1.19) and in two osteosarcoma OS cell lines (MG63 and HOS). A miR-125b-5p mimic or inhibitor was transfected in the osteosarcoma cell lines via liposome and the changes in cell proliferation and migration were detected with EDU and Transwell experiments. Bioinformatic analysis was conducted for predicting the target gene of miR-125b-5p, and the expression level of RAB3D in hFOB1.19, MG63, and HOS cells was detected by Western blotting. In the two osteosarcoma cell lines transfected with miR-125b-5p mimic or inhibitor, the expression levels of RAB3D mRNA and protein in osteosarcoma cells were examined with qRT-PCR and Western blotting. The effects of RAB3D overexpression, RAB3D knockdown, or overexpression of both miR-125b-5p and RAB3D on the proliferation and migration of cells were assessed using EDU and Transwell experiments. The two osteosarcoma cell lines had significantly lower expression levels of miR-125b-5p (P < 0.05). Bioinformatic analysis predicted that RAB3D was a possible target gene regulated by miR-125b-5p. In osteosarcoma cells, overexpression of miR-125b-5p significantly lowered the expression of RAB3D protein (P < 0.05); inhibiting miR-125b-5p expression significantly decreased RAB3D expression only at the protein level (P < 0.05) without obviously affecting its mRNA level. Modulation of miR-125b-5p and RAB3D levels produced opposite effects on proliferation and migration of osteosarcoma cells, and in cells with overexpression of both miR-125b-5p and RAB3D, the effect of RAB3D on cell proliferation and migration was blocked by miR-125b-5p overexpression (P < 0.05). Overexpression of miR-125b-5p inhibits the proliferation and migration of osteosarcoma cells by regulating the expression of RAB3D at the post-transcriptional level.

Retracted] Suppressive effect of microRNA‑138 on the proliferation and invasion of osteosarcoma cells via targeting SIRT1.

[This retracts the article DOI: 10.3892/etm.2017.4426.].

Retracted] Inhibiting proliferation and metastasis of osteosarcoma cells by downregulation of long non‑coding RNA colon cancer‑associated transcript 2 targeting microRNA‑143.

[This retracts the article DOI: 10.3892/ol.2021.12526.].

Retracted] MicroRNA‑708 inhibits the proliferation and invasion of osteosarcoma cells by directly targeting ZEB1.

Following the publication of this paper, it was drawn to the Editors' attention by a concerned reader that cell migration assay data shown in Figs.2C and 5D were strikingly similar to data that had appeared in different form in other articles by different authors. Owing to the fact that the contentious data in the above article had already been published elsewhere prior to its submission to Molecular Medicine Reports, the Editor has decided that this paper should be retracted from the Journal. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive a reply. The Editor apologizes to the readership for any inconvenience caused. [Molecular Medicine Reports 16: 3948‑3954, 2019; DOI: 10.3892/mmr.2019.10013].

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

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

FGF23 promotes proliferation, migration and invasion by regulating miR-340-5p in osteosarcoma

BackgroundIncreasing evidences have been indicated that FGF23 is associated with the biological behavior of malignant tumors, but its role in osteosarcoma and the specific mechanism need to be elucidated. The purpose of this study is to investigate the effects of FGF23 on the proliferation, migration and invasion of osteosarcoma cells, and the possible molecular mechanisms.MethodsWestern blot was used to detect differences in FGF23 expression in osteosarcoma cells MG-63 and U2-OS and osteoblasts hFOB1.19. FGF23-overexpressing adenoviruses and FGF-silencing plasmids were transfected into osteosarcoma cells, and transfection efficiency was verified using Western blot. MTT and colony formation assays were performed to detect osteosarcoma cell proliferation. Cell cycle was measured by flow cytometry. Scratch assay, holographic imaging cell analyzer Holomonitor ® M4 and transwell were applied to detect cell migration and invasion. Dual-luciferase reporter assay was performed to validate the interaction between FGF23 and miR-340-5p. Changes in miR-340-5p mRNA levels were measured by QRT-PCR.ResultsFGF23 is highly expressed in osteosarcoma cells compared to hFOB1.19. Overexpression of FGF23 significantly promoted the proliferation, migration and invasion of MG-63 and U2-OS cells. MiR-340-5p is a target of FGF23. Transfection of miR-340-5p mimics reversed the promoting effects of FGF23 on proliferation, migration and invasion of MG-63 and U2-OS cells.ConclusionFGF23 promotes osteosarcoma cell proliferation, migration and invasion by targeting miR-340-5p gene expression.

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.

ALKBH5 involves in osteosarcoma tumor progression by mediating Notch signaling

AbstractALKBH5 is the major demethylase of ribonuclease m6A and exerts these multiple biological functions in cancer. In this study, we mainly explore the use of ALKBH5 in the development and progression of osteosarcoma and elucidate the potential molecular mechanisms by which it functions. Relative to human osteoblast cell lines (NHOst), we detected ALKBH5 expression in osteosarcoma cell lines (HOS, U2OS, and MG‐63) by RT‐PCR and western blot. By overexpression and knockout of ALKBH5 gene, to observe the effect of ALKBH5 on apoptosis, invasion and epithelial‐mesenchymal transition (EMT) of osteosarcoma cells, as well as the effect of Notch signaling pathway. We found that ALKBH5 was significantly higher in osteosarcoma cell lines than in osteoblastic cell lines. In addition, ALKBH5 overexpression promoted the proliferation, migration, and invasion of osteosarcoma cells, and simultaneously activated Notch signaling pathway and up‐regulated E‐cadherin protein. Knockout of ALKBH5 inhibited these effects in osteosarcoma cells. It was also found that up‐regulation of ALKBH5 could promote the proliferation of osteosarcoma cells in vitro and in vivo. ALKBH5 can be involved in osteosarcoma development through Notch signaling pathway regulation. ALKBH5 is therefore expected to be a new target in the treatment of osteosarcoma.

MIR503HG Overexpression Inhibits the Malignant Behaviors of Osteosarcoma Cells by Sponging miR-103a-3p

Osteosarcoma (OS) is the most representative primary bone tumour in children and teenagers. This study explored the regulatory effects of long noncoding RNA MIR503HG (MIR503HG) on the biological functions of OS cells, and further investigated the potential mechanism of MIR503HG function exertion by analyzing the microRNA-103a-3p (miR-103a-3p) in OS cells and tissues. The expression of MIR503HG was examined using reverse transcription-quantitative PCR. OS cell proliferation was assessed by CCK-8 assay. Transwell assay was used to evaluate the migration and invasion of OS cells. The interaction between MIR503HG and miR-103a-3p was detected using the Dual-luciferase reporter assay. Forty-six paired OS tissues were collected, and the expression and correlation of MIR503HG and miR-103a-3p were evaluated. The expression of MIR503HG were significantly decreased in both OS cells and tissues. Over-expression of MIR503HG inhibited OS cell proliferation, migration and invasion. miR-103a-3p was directly targeted by MIR503HG in OS cells, and mediated the inhibitory effects of MIR503HG on OS cell malignant behaviors. miR-103a-3p expression was upregulated in OS tissues, which was negatively correlated with MIR503HG expression levels. The expression of MIR503HG was associated with OS patients' tumor size, differentiation, distant metastasis and clinical stage. Decreased MIR503HG in OS tissues and cell lines served as a tumor suppressor by inhibiting OS cell malignant behaviors through sponging miR-103a-3p. The findings of this study may provide evidence for the development of novel therapeutic targets of OS.

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.