Human Osteosarcoma Cell Line MG-63 Research Articles

Synthesis and preliminary cytotoxicity evaluation of water soluble pentacyclic triterpenoid phosphonates.

Synthesis, solubility and cytotoxicity evaluation of anionic phosphonates derived from betulin, betulinic acid, oleanolic acid and ursolic acid is reported. Phosphonate moieties were successfully installed at terpenoid C28 by carboxylic acid deprotonation/alkylation sequence using (dimethoxyphosphoryl)methyl trifluoromethanesulfonate as alkylation reagent. Also, betulin-derived and ether-linked bis-phosphonate is obtained and characterized. After demethylation in the presence of TMSI the resulting phosphonic acids were transformed into their disodium salts. All target compounds display excellent water solubility, which was determined by qNMR in D2O. Cytotoxicity tests were performed in different concentrations of each compound (10-50 µM) against human osteosarcoma cell line MG-63 and osteoblast precursor cell line MC3T3-E1. Improved aqueous solubility and low cytotoxicity profile of the newly designed triterpenoid phosphonates reveal high potential for various medicinal chemistry and pharmacological applications in the future.

Retraction Note: ROS-mediated cytotoxic activity of ZnO and CeO2 nanoparticles synthesized using the Rubia cordifolia L. leaf extract on MG-63 human osteosarcoma cell lines.

Retraction Note: ROS-mediated cytotoxic activity of ZnO and CeO2 nanoparticles synthesized using the Rubia cordifolia L. leaf extract on MG-63 human osteosarcoma cell lines.

Multifunctional zinc oxide loaded stearic acid surfaces on biodegradable magnesium WE43 alloy with hydrophobic, self-cleaning and biocompatible attributes

Biodegradable Mg alloys are one of the most promising materials for implant applications, for which the widespread use is hampered by rapid degradation in physiological environment. The present study explores the development of a novel zinc-oxide (ZnO) loaded stearic acid (SA) coating on medical grade WE43 alloy using a facile, and environment-friendly technique for promising biomaterial surface applications. Morphology and chemical analyses reveal the development of a layered coating surface with uniformly dispersed ZnO nanoparticles in SA matrix. The developed coating exhibits hydrophobic performance (contact angle of 135°) along with the retainment of hydrophobicity under varying chemical (acidic pH of 1 and basic pH of 13) and mechanical (post scratch testing and peel-off studies) conditions. The observed surface water repellency facilitates self-cleaning performance pointing towards its efficacy against potential biofilm formation. The developed coating demonstrates superior resistance against surface degradation during immersion studies in phosphate buffer saline solution (pH = 7.4) and better cell viability with MG-63 (human osteosarcoma) cell line. The approach presented here sets a platform for the development of efficient coatings on biodegradable WE43 alloys surfaces for potential biomaterial technologies.

Poly(styrene-co-methyl methacrylate)-silver/reduced graphene oxide-nano hydroxyapatite nanocomposites for bone cement applications

Herein, we report (polystyrene-co-polymethylmethacrylate/silver/reduced graphene oxide)-(nano-hydroxyapatite) ((PS-PMMA/Ag/RGO)-(nHA)) nanocomposites as potential bone cement. The polymer nanocomposites were characterized using Fourier Transform Infrared spectroscopy (FT-IR), X-ray diffraction (XRD), nano-indentation, thermal, and electron microscopic methods. The FT-IR and XRD results confirmed the successful formation of the nanocomposites. The elastic modulus (E) was found to be 6.85 GPa, and hardness (H) was 0.181 GPa for the nanocomposite bone cement samples, while the E and H values of commercial counterparts are 7.22 and 0.218 GPa, respectively. The thermogravimetric analysis (TGA) has revealed that the nanocomposite bone cement are stable up to 371 °C. The addition of nHA enhances the biocompatibility of bone cement. Cytotoxicity studies were conducted using human osteosarcoma MG63 cell lines. In-vitro studies showed that the material does not display any toxicity on the MG63 cell line, and increased concentration of nHA did not significantly impact the material’s toxicity, only impacting the curing kinetics of the cement.

LncRNA-PVT1 Inhibits Ferroptosis through Activating STAT3/GPX4 Axis to Promote Osteosarcoma Progression.

Osteosarcoma (OS) is a primary malignant bone tumor in the pediatric and adolescent populations. Long non-coding RNAs (LncRNAs), such as plasma-cytoma variant translocation 1 (PVT1), have emerged as significant regulators of OS metastasis. Recent studies have indicated that activation of signal transducer and activator of transcription 3 (STAT3) signaling, which might be controlled by PVT1, inhibits ferroptosis to promote the malignant progression of cancer. Therefore, the present study aimed to determine the role of PVT1 in OS pathogenesis and investigate whether PVT1 affects OS progression by regulating STAT3/GPX4 pathway-mediated ferroptosis. The human OS cell line MG63 were transfected with sh-PVT1 plasmid to inhibit PVT1 expression, with or without co-transfection with a STAT3 overexpression plasmid. The expression of PVT1 was determined by real-time quantitative polymerase chain reaction (RT-qPCR). The proliferation, migration, invasion, and apoptosis of MG63 cells were determined using the cell counting kit-8 (CCK8), Transwell assay, and flow cytometry. The levels of malondialdehyde (MDA), Fe2+, and glutathione (GSH) were determined by ELISA kits, whereas reactive oxygen species (ROS) level was determined by immunofluorescence. The protein expression levels of STAT3, p-STAT3, and glutathione peroxidase 4 (GPX4) were detected by western blot (WB). PVT1 expression was significantly increased in MG63 cells. When knocking down PVT1 with sh-PVT1 plasmid, the proliferation, migration, and invasion of MG63 cells were markedly inhibited, while the rate of apoptosis was upregulated. Further investigation revealed that MG63 cells with PVT1 knockdown exhibited elevated levels of MDA, Fe2+, and ROS. In addition, the inhibition of PVT1 expression resulted in decreased levels of GSH and inhibited expression of p-STAT3 and GPX4. When sh-PVT1 was co-transfected with STAT3 overexpression plasmid in MG63 cells, the increased levels of MDA, Fe2+, and ROS were downregulated, and the decreased expressions of GSH, p-STAT3, and GPX4 were upregulated. PVT1 promotes OS metastasis by activating the STAT3/GPX4 pathway to inhibit ferroptosis. Targeting PVT1 might be a novel therapeutic strategy for OS treatment.

Osteogenic assessment of leukocyte platelet-rich fibrin and injectable platelet-rich fibrin in the human osteosarcoma MG - 63 cell line in chronic periodontitis patients: An in vitro study.

The burgeoning interest in implant and regenerative dental care has led to a notable upsurge in the utilization of regenerative modalities. The intent of the present investigation was to evaluate the osteogenic ability of two different concentrated platelet groups at various concentrations in the human osteosarcoma MG-63 cell line. Blood samples from 21 volunteers with chronic periodontitis were collected which were then centrifuged in accordance with the protocols of Choukroun et al. and Miron et al. to produce leukocyte- and platelet-rich fibrin (L-PRF) and injectable platelet-rich fibrin (I-PRF), respectively. Following MG-63 cell culture, the osteogenic ability of 0, 4%, and 20% concentrations of both L-PRF and I-PRF were determined using the real-time polymerase chain reaction assay. The results showed that 20% I-PRF (1.52 ± 0.24) and 4% L-PRF (1.42 ± 0.37) had the highest amount of bone morphogenetic protein 2 and osteocalcin, respectively. I-PRF appears to promote the initial differentiation of cells.

Anti-cancer targets and molecular mechanisms of formononetin in treating osteosarcoma based on network pharmacology.

Osteosarcoma (OS) is a multifactorial bone malignancy that accounts for most cancers in children and adolescents. Formononetin has been proven to exhibit various pharmacological effects including anti-tumor, anti-obesity, anti-inflammation, and neuroprotective effects. Few studies have examined the pharmacological activities of formononetin in OS treatment, but the mechanism has not yet been completely elucidated. Network pharmacology is a new method based on the theory of system biology for analyzing the network of biological systems and selecting specific signal nodes for multi-target drug molecular design. Here, we used network pharmacology to explore the possible mechanism of formononetin in OS treatment. Human OS cell line MG63 was processed with four concentrations (0, 2, 5, 8 μg/mL) of formononetin. Subsequently, an MTT assay was performed to test cell proliferation and a scratch test was used to evaluate the migration ability of cancer cells. Caspase-3, p53, p21, and bcl-2 expression levels incubated with different concentrations of formononetin in MG63 cells were determined using Western blotting. After treated with formononetin for 48 h, MG63 cells exhibited marked apoptosis. The results revealed that certain concentrations of formononetin significantly exerted inhibitory effects on MG63 cell proliferation. Furthermore, formononetin decreased the bcl-2 level in MG63 cells but increased caspase-3, p21, and p53 levels in a concentration-dependent manner. Additionally, formononetin suppressed the expression of SATB2. Therefore, formononetin could dose-dependently inhibit MG63 cell proliferation and induce apparent cell apoptosis, providing a candidate treatment for OS, whereas SATB2 could be a potential prognostic biomarker for screening OS and therapeutic target of formononetin.

Fabrication of highly ordered willemite/PCL bone scaffolds by 3D printing: Nanostructure effects on compressive strength and in vitro behavior

In this study, first willemite (Zn2SiO4) micro and nano-powders were synthesized by the sol-gel method. X-ray diffraction (XRD), transmission electron microscopy (TEM), and dynamic light scattering (DLS) were applied to characterize the crystalline phases and particle size of powders. Then polycaprolactone (PCL) polymer scaffolds containing 20 wt% willemite were successfully fabricated by the DIW 3D printing (direct ink writing) method. The effects of willemite particle size on compressive strength, elastic modulus, degradation rate, and bioactivity of the composite scaffolds were investigated. The results showed that nanoparticle willemite/PCL (NW/PCL) scaffolds had 33.1% and 58.1% higher compressive strength and the elastic modulus of NW/PCL were 1.14 and 2.45 times better compared to micron size willemite/PCL (MW/PCL) and pure PCL scaffolds, respectively. Scanning electron microscopy (SEM) images and Energy-dispersive X-ray spectroscopy map (EDS map) results indicated that willemite nanoparticles, unlike microparticles, were smoothly embedded in the scaffold struts. In vitro tests also revealed an improvement in bone-like apatite formation ability and an increase in the degradation rate up to 2.17% by decreasing the willemite particle size to 50 nm. In addition, NW/PCL rendered significant enhancement in cell viability and cell attachment during the culture of MG-63 human osteosarcoma cell line. Nanostructure had also a positive effect on ALP activity and biomineralization in vitro.

Anticancer effect of crizotinib on osteosarcoma cells by targeting c-Met signaling pathway.

C-Met receptor and its ligand hepatocyte growth factor (HGF) are overexpressed in a variety of osteosarcoma cell lines and osteosarcoma pathological samples. It is suggested that c-Met/HGF plays an important role in the development of osteosarcoma. This study aimed to explore the anticancer effect of the c-Met-targeted drug crizotinib on osteosarcoma (OS) cells. The effects of crizotinib on the proliferation of osteosarcoma cells (SaOS2, MG-63 and MNNG) at different concentrations were detected by CCK8. Human osteosarcoma cell line MG-63 was used as an in vitro model to evaluate the effects of 2.5 μM crizotinib, 5.0 μM crizotinib and DMSO on cell apoptosis, cell cycle, migration and invasion. The expression of the c-Met signaling pathway in osteosarcoma cells was detected by western blot. The results showed that crizotinib inhibited the proliferation of cell lines in a concentration-dependent manner. Crizotinib significantly increased the number of apoptotic cells compared with the control group. Compared with the control group, crizotinib increased G0/G1 phase cells and decreased S phase cells. Compared with the control group, crizotinib inhibited the migration and invasion of osteosarcoma cells and decreased the expression of c-Met/Gab1/STAT5. This study will provide a promising therapeutic target and theoretical basis for the clinical application of crizotinib in osteosarcoma.

Human osteosarcoma cells in response to ELF-MF: Morphological remodeling compared to cell proliferation.

The present study aimed to assess the effects of extremely low-frequency electromagnetic fields (ELF-MF) on structural changes of human osteosarcoma cells by analyzing the stained cytoskeleton for assessing the relationship between the fractal dimension parameter and proliferation rate of radiation-induced cells. In this study, 2-mT magnetic fields with various waveforms, including sinusoidal, triangular, and pulsed shapes, were employed to determine the biological effects of ELF-EMF on the human osteosarcoma MG-63 cell line. All experiments were performed in two modes: continuous exposure at 3 h and fractionated irradiations at 3 consecutive days. Afterward, the proliferation assay was implemented for assessing the cell proliferation in each group. Moreover, immunofluorescence staining and confocal imaging were performed to determine the cell shape index. Furthermore, fractal dimension analysis was carried out by processing morphological images. The proliferation and shape index parameters of radiation-induced osteosarcomas significantly decreased compared with non-irradiated cells. In addition, fractal dimensions significantly increased following fractionated exposure at 3 consecutive days. Assessing the fractal dimensions can be considered as a new morphological index for the prognosis of the structural remodeling of human osteosarcoma cells in response to fractionated irradiation of ELF-MF. In addition, various waveforms induce a similar effect on morphological remodeling and cell proliferation.

An Exploration of Osteosarcoma Metastasis Diagnostic Markers Based on Tumor-Associated Neutrophils.

The high rate of the recurrence and metastasis of osteosarcoma (OS) is the major cause of its poor prognosis. There is a strong correlation between tumor-associated neutrophils (TANs) and tumor progression, progression, and metastasis. This study aimed to identify potential markers that could predict OS metastasis based on analysis of TANs in the tissues of OS patients. A single-cell sequencing dataset (GSE152048), containing seven primary OS lesions, two recurrent OS lesions, and two lung metastatic OS lesions was used for TANs subset identification using the R software (version 4.1.0, R Project for Statistical Computing, Vienna, Austria; https://www.r-project.org/). Immune cell infiltration and immune score were analyzed using CIBERSORT algorithm and ESTIMATE database, respectively. The differentially expressed genes (DEGs) of TANs were used for weighted gene co-expression network analysis (WGCNA) to screen key genes associated with OS metastasis. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analysis were used to analyze the functions and signaling pathways involved in key genes. The mRNA levels of protein phosphatase 2 regulatory subunit B'gamma (PPP2R5C) were validated in human osteosarcoma cell lines U2-OS and MG63, human normal cervical endometrial cell line HUCEC, and human foreskin fibroblast (HFF-1) cell line by real-time qPCR (RT-qPCR). PPP2R5C-siRNA991 was transfected into U2-OS and MG63 for 48 h, then the expression levels of PPP2R5C, AKT serine/threonine kinase (AKT), and phospho-AKT (p-AKT) were determined by RT-qPCR and Western blotting. Cell proliferation, migration, and apoptosis were measured by cell counting kit-8 (CCK-8), Transwell, and flow cytometry, respectively. We identified TANs subsets in primary, metastatic, and recurrent OS. Immune infiltration analysis showed that TANs were expressed in OS. Compared with non-metastatic OS, metastatic OS had lower stromal score, immune score, ESTIMATE score, and higher tumor purity. WGCNA classified DEGs into five clusters, according to their function and identified PPP2R5C, protein phosphatase 2 regulatory subunit B'epsilon (PPP2R5E), tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein gamma (YWHAG) and CREB binding protein (CREBBP), as potential markers that may affect TANs-induced OS metastasis via hypoxia inducible factor 1 (HIF-1), phosphatidylinositol 3-kinases (PI3K)-AKT and Janus kinase (JAK)-signal transducers and activators of transcription (STAT) signaling pathways. In vitro experiments demonstrated that the mRNA and protein expressions of PPP2R5C, PPP2R5E, YWHAG, and CREBBP were highly expressed in U2-OS and MG63 cells (p < 0.01). Furthermore, PPP2R5C reduced proliferation and migration (p < 0.01) and increased apoptosis and p-AKT protein levels in U2-OS and MG6 cells (p < 0.01). PPP2R5C affects OS metastasis via PI3K/AKT pathway, which may be a potential marker for OS metastasis and recurrence.

Sorafenib inhibits doxorubicin-induced PD-L1 upregulation to improve immunosuppressive microenvironment in Osteosarcoma.

Although undergoing conventional chemotherapy significantly improves the prognosis of Osteosarcoma, chemoresistance and failure of therapy is still a significant challenge. Furthermore, conventional chemotherapy, like doxorubicin, would upregulate the expression of programmed death-ligand 1 (PD-L1) which caused an immunosuppressive microenvironment and unsatisfied treatment result in Osteosarcoma. Thus, it is urgent to explore a strategy to overcome this disadvantage. Human Osteosarcoma cell line MG63 and mouse Osteosarcoma cell line K7 were included in this study. Subcutaneous tumor model was used by injection of K7 cells in BALB/C mice to test the effect of doxorubicin and sorafenib on tumor growth. PD-L1 expression was tested in vitro (flow cytometry, western blot and PCR) and in vivo (flow cytometry and immunohistochemistry). Proportion of immune cells (CD4, CD8, Tregs, and cytotoxic T lymphocytes) in vivo was analyzed with flow cytometry. Combination of sorafenib and doxorubicin inhibited tumor growth significantly in vivo. Doxorubicin increased PD-L1 expression in vitro and in vivo, while sorafenib inhibited doxorubicin-induced PD-L1 upregulation in vitro and in vivo. Proportion of interferon-γ-secreting CD8 + T lymphocytes in tumor tissue was increased significantly when sorafenib was combined with doxorubicin, while proportion of CD4, CD8, and Tregs was not significantly changed. Extracellularsignal-regulatedkinases (ERK) pathway could be one of the key mechanisms by which doxorubicin induced upregulation of PD-L1 in Osteosarcoma cells. Combination of sorafenib and conventional chemotherapeutic reagents is a potent strategy to improve treatment effectiveness by modulating tumor microenvironment in Osteosarcoma through increasing proportion of cytotoxic T lymphocytes.

SIRT2 promotes the viability, invasion and metastasis of osteosarcoma cells by inhibiting the degradation of Snail

Osteosarcomas (OS) are highly metastatic and usually lead to poor outcomes. Epithelial-mesenchymal transition (EMT) is reported to be a critical event in metastasis. SIRT2 exerts dual functions in many different tumors. However, the underlying molecular mechanisms of SIRT2 in osteosarcoma cell metastasis and the question of whether SIRT2 regulates EMT have not been fully explored. In this study, we confirmed that SIRT2 was highly-expressed in human osteosarcoma MG63 and Saos-2 cell lines. The viability, migration and invasion of osteosarcoma cells were inhibited by knockdown of SIRT2 and were enhanced by overexpression of SIRT2. Moreover, SIRT2 positively regulated EMT and upregulated the protein levels of the mesenchymal markers N-cadherin and Vimentin and the levels of MMP2 and MMP9. A xenograft mouse model showed that SIRT2 knockdown in osteosarcoma cells led to reduced tumor growth, decreased expression of mesenchymal markers and impaired lung and liver metastasis in vivo. Furthermore, we showed that SIRT2 interacted with and upregulated the protein level of the EMT-associated transcription factor Snail. SIRT2 inhibited Snail degradation via its deacetylase activity. Knockdown of Snail abrogated the promoting effects of SIRT2 on migration and invasion of osteosarcoma cells. In conclusion, SIRT2 plays a crucial role in osteosarcoma metastasis by inhibiting Snail degradation and may serve as a novel therapeutic target to manage osteosarcoma.

Strontium Substituted β-Tricalcium Phosphate Ceramics: Physiochemical Properties and Cytocompatibility.

Sr2+-substituted β-tricalcium phosphate (β-TCP) powders were synthesized using the mechano-chemical activation method with subsequent pressing and sintering to obtain ceramics. The concentration of Sr2+ in the samples was 0 (non-substituted TCP, as a reference), 3.33 (0.1SrTCP), and 16.67 (0.5SrTCP) mol.% with the expected Ca3(PO4)2, Ca2.9Sr0.1(PO4)2, and Ca2.5Sr0.5(PO4)2 formulas, respectively. The chemical compositions were confirmed by the energy-dispersive X-ray spectrometry (EDX) and the inductively coupled plasma optical emission spectroscopy (ICP-OES) methods. The study of the phase composition of the synthesized powders and ceramics by the powder X-ray diffraction (PXRD) method revealed that β-TCP is the main phase in all compounds except 0.1SrTCP, in which the apatite (Ap)-type phase was predominant. TCP and 0.5SrTCP ceramics were soaked in the standard saline solution for 21 days, and the phase analysis revealed the partial dissolution of the initial β-TCP phase with the formation of the Ap-type phase and changes in the microstructure of the ceramics. The Sr2+ ion release from the ceramic was measured by the ICP-OES. The human osteosarcoma MG-63 cell line was used for viability, adhesion, spreading, and cytocompatibility studies. The results show that the introduction of Sr2+ ions into the β-TCP improved cell adhesion, proliferation, and cytocompatibility of the prepared samples. The obtained results provide a base for the application of the Sr2+-substituted ceramics in model experiments in vivo.

Physicochemical and biological studies of Ni(II), Cu(II) and Zn(II) ternary complexes of sulfaquinoxaline and 2,2’-bipyrimidine

Three monomeric ternary complexes of Ni(II) (1), Cu(II) (2), and Zn(II) (3) with sulfaquinoxaline (SQO), and 2,2’-bipyrimidine (bpm) as ligands have been prepared and their crystal structures have been determined. The complexes are formulated as M(SQO)2bpm·2H2O, completing MN6 coordination spheres. Hirshfeld surface analysis was employed to study the intermolecular interactions in the crystal lattices of the compounds. From these studies, it was found that hydrogen bonding and π-stacking interactions play an important role. Besides, the complexes have been characterized by FTIR and UV-Visible spectroscopies, and thermogravimetric techniques. The cytotoxicity of the complexes was screened against the tumoral A549 (human lung adenocarcinoma) and MG-63 (human osteosarcoma) cell lines. The complexes showed enhanced antibacterial activity against S. aureus and S. epidermidis as compared with the free SQO ligand.

Efficacy of glycoprotein-based nanocurcumin/silk fibroin electrospun scaffolds: Perspective for bone apatite formation

In this research, a blend of poly (vinyl) alcohol (PVA), silk fibroin nanofibers (SF-NFs), hydroxyapatite nanoparticles (HA-NPs), and curcumin nanoparticles (Cu-NPs) were used to design a nanofibrous scaffold (NFS), by electrospun method, for their possible application in bone apatite formation. The prepared nanofibrous scaffold (NFS) was investigated using physicochemical, mechanical, cell viability, etc. The bioactivity test of NFS was evaluated after immersion in SBF (simulated body fluid). NFS from PVA, SF-NFs, HA-NPs, and Cu-NPs exhibited outstanding physicochemical, mechanical, and antibacterial properties. PVA: SF-NFs: HA-NPs: Cu-NPs scaffold excellent antimicrobial performance against E.coli (4.16 ± 0.16 mm) and S.aureus (4.88 ± 0.10 mm). Biocompatibility studies were assessed using human osteosarcoma MG63 cell line, which displayed 100% viable cell presence in PVA: SF-NFs: HA-NPs: Cu-NPs. Based on the characterization, results indicated that they are excellent scaffolds for bone tissue regeneration.

Circ-RANGAP1/MicroRNA-542-3p/Myosin Regulatory Light Chain Interacting Protein Axis Modulates the Osteosarcoma Cell Progression.

Objective This study is aimed at exploring the influence of circular RNA- (circRNA-) RANGAP1 targeting microRNA- (miR-) 542-3p/myosin regulatory light chain interacting protein (MYLIP) on the biological function of osteosarcoma (OS) cells. Methods Tumor tissues and normal tissues were collected from OS patients and circ-RANGAP1, miR-542-3p, and MYLIP expression was tested by RT-qPCR. The correlation between the clinicopathology/prognosis of patients with OS and circ-RANGAP1 expression was observed. Human OS cell line MG-63 was screened to determine the influences of circ-RANGAP1 and miR-542-3p on OS cell progression. The targeting relation of circ-RANGAP1, miR-542-3p, and MYLIP was probed. Results circ-RANGAP1 expression was elevated in tumor tissues from OS patients, which was correlated to the poor clinicopathology. circ-RANGAP1 expression was augmented in males or patients younger than 20 years old or patients with advanced OS. Higher circ-RANGAP1 expression indicated a poor prognosis in OS patients. After silencing circ-RANGAP1 or elevating miR-542-3p in MG63 cells, cell progression was limited. miR-542-3p downregulation reduced the therapeutic efficacy of silenced circ-RANGAP1. circ-RANGAP1 bound with miR-542-3p to target MYLIP. Conclusion Silenced circ-RANGAP1 boosts MYLIP expression via competitive binding of miR-542-3p to facilitate OS cell progression.

HO-3867 Induces Apoptosis via the JNK Signaling Pathway in Human Osteosarcoma Cells.

Metastatic osteosarcoma often results in poor prognosis despite the application of surgical en bloc excision along with chemotherapy. HO-3867 is a curcumin analog that induces cell apoptosis in several cancers, but the apoptotic effect and its mechanisms on osteosarcoma cells are still unknown. After observing the decrease in cellular viability of three human osteosarcoma U2OS, HOS, and MG-63 cell lines, and the induction of cellular apoptosis and arrest in sub-G1 phase in U2OS and HOS cells by HO-3867, the human apoptosis array showed that heme oxygenase (HO)-1 and cleaved caspase-3 expressions had significant increases after HO-3867 treatment in U2OS cells and vice versa for cellular inhibitors of apoptosis (cIAP)1 and X-chromosome-linked IAP (XIAP). Western blot analysis verified the results and showed that HO-3867 activated the initiators of both extrinsic caspase 8 and intrinsic caspase 9, and significantly increased cleaved PARP expression in U2OS and HOS cells. Moreover, with the addition of HO-3867, ERK1/2, and JNK1/2 phosphorylation were increased in U2OS and HOS cells. Using the inhibitor of JNK (JNK in 8), HO-3867’s increases in cleaved caspases 3, 8, and 9 could be expectedly suppressed, indicating that JNK signaling is responsible for both apoptotic pathways, including extrinsic and intrinsic, in U2OS and HOS cells caused by HO-3867. Through JNK signaling, HO-3867 has proven to be effective in causing both extrinsic and intrinsic apoptotic pathways of human osteosarcoma cells.

TBP, PPIA, YWHAZ and EF1A1 Are the Most Stably Expressed Genes during Osteogenic Differentiation

RT-qPCR is the gold standard and the most commonly used method for measuring gene expression. Selection of appropriate reference gene(s) for normalization is a crucial part of RT-qPCR experimental design, which allows accurate quantification and reliability of the results. Because there is no universal reference gene and even commonly used housekeeping genes’ expression can vary under certain conditions, careful selection of an appropriate internal control must be performed for each cell type or tissue and experimental design. The aim of this study was to identify the most stable reference genes during osteogenic differentiation of the human osteosarcoma cell lines MG-63, HOS, and SaOS-2 using the geNorm, NormFinder, and BestKeeper statistical algorithms. Our results show that TBP, PPIA, YWHAZ, and EF1A1 are the most stably expressed genes, while ACTB, and 18S rRNA expressions are most variable. These data provide a basis for future RT-qPCR normalizations when studying gene expression during osteogenic differentiation, for example, in studies of osteoporosis and other bone diseases.

Expression and Clinical Significance of High‐Mobility Group AT‐hook 2 (HMGA2) in Osteosarcoma

ObjectiveAlthough high‐mobility group AT‐hook 2 (HMGA2) has been shown to have crucial roles in the pathogenesis and metastasis of various malignancies, its expression and significance in osteosarcoma remain unknown. Here we evaluate the expression, clinical prognostic value, and overall function of HMGA2 in osteosarcoma.MethodsSixty‐nine osteosarcoma patient specimens within a tissue microarray (TMA) were analyzed by immunohistochemistry for HMGA2 expression. Demographics and clinicopathological information including age, gender, tumor location, metastasis, recurrence, chemotherapy response, follow‐up time, and disease status were also collected. After validation of expression, we determined whether there was a correlation between HMGA2 expression and patient clinicopathology. HMGA2 expression was also evaluated in osteosarcoma cell lines and patient tissues by Western blot, we analyzed the expression of HMGA2 in the human osteosarcoma cell lines MG63, 143B, U2OS, Saos‐2, MNNG/HOS, and KHOS. HMGA2‐specific siRNA and clonogenic assays were then used to determine the effect of HMGA2 inhibition on osteosarcoma cell proliferation, growth, and chemosensitivity.ResultsHMGA2 expression was elevated in the osteosarcoma patient specimens and human osteosarcoma cell lines. HMGA2 was differentially expressed in human osteosarcoma cell lines. Specifically, a relatively high expression of HMGA2 was present in KHOS, MNNG/HOS, 143B and a relatively low expression was in MG63, U2OS as well as Saos‐2. HMGA2 expression is correlated with metastasis and shorter overall survival. High HMGA2 expression is an independent predictor of poor osteosarcoma prognosis. There was no significant correlation between HMGA2 expression and the age, gender, or tumor site of the patient. HMGA2 expression is predominantly within the nucleus. The expression of HMGA2 also directly correlated to neoadjuvant chemoresistance. There was a significant reduction of HMGA2 expression in the siRNA transfection group. After the use of siRNA, the proliferation of osteosarcoma cells is decreased and the chemosensitivity of osteosarcoma cells is significantly increased.ConclusionOur study supports HMGA2 as a potential prognostic biomarker and therapeutic target in osteosarcoma.