Injectable Inflammation-Responsive Hydrogels for Microenvironmental Regulation of Intervertebral Disc Degeneration.

Chronic local inflammation and excessive cell apoptosis in nucleus pulposus (NP) tissue are the main causes of intervertebral disc degeneration (IDD). Stimuli-responsive hydrogels have great potential in the treatment of IDD by facilitating localized and controlled drug delivery. Herein, an injectable drug-loaded dual stimuli-responsive adhesive hydrogel for microenvironmental regulation of IDD, is developed. The gelatin methacryloyl is functionalized with phenylboronic acid groups to enhance drug loading capacity and enable dual stimuli-responsive behavior, while the incorporation of oxidized hyaluronic acid further improves the adhesive properties. The prepared hydrogel exhibits an enhanced drug loading capacity for diol-containing drugs, pH- and reactive oxygen species (ROS)-responsive behaviors, excellent radical scavenging efficiency, potent antibacterial activity, and favorable biocompatibility. Furthermore, the hydrogel shows a beneficial protective efficacy on NP cells within an in vitro oxidative stress microenvironment. The in vivo results demonstrate the hydrogel's excellent therapeutic effect on treating IDD by maintaining water retention, restoring disc height, and promoting NP regeneration, indicating that this hydrogel holds great potential as a promising therapeutic approach for regulating the microenvironment and alleviating the progression of IDD.

Injectable pathological microenvironment-responsive anti-inflammatory hydrogels for ameliorating intervertebral disc degeneration.

Chronic local inflammation and resulting cellular dysfunction of nucleus pulposus (NP) cells are important pathogenic factors of intervertebral disc degeneration (IDD). Injectable pathological microenvironment-responsive hydrogels hold significant potential for treating IDD by adapting to dynamic microenvironment of IDD. Herein, we proposed an injectable gelatin-based hydrogel drug delivery system that could respond to the pathological microenvironment of IDD for controlled release of anti-inflammatory drug to promote degenerative NP repair. The hydrogel system was prepared by conjugating phenylboronic acid-modified gelatin methacryloyl (GP) with the naturally extracted anti-inflammatory drug epigallocatechin-3-gallate (EGCG) through dynamic boronic esters. The hydrogel exhibited excellent degradability, injectability, antioxidant properties, anti-inflammatory effects, and biocompatibility. It also displayed responsive-release of EGCG under high reactive oxygen species (ROS) levels and acidic conditions. The hydrogel demonstrated remarkable cytoprotective effects on NP cells in both hyperactive ROS environments and inflammatory cytokine-overexpressed environments in vitro. In vivo studies revealed that the hydrogel injected in situ could effectively ameliorate the intervertebral disc degeneration by maintaining the disc height and NP tissue structure in a rat IDD model. The hydrogel system exhibited excellent biocompatibility and responsive-release of diol-containing drugs in pathological microenvironments, indicating its potential application as a drug delivery platform.

Meniscus-Inspired Self-Lubricating and Friction-Responsive Hydrogels for Protecting Articular Cartilage and Improving Exercise.

Meniscus injuries are associated with the degeneration of cartilage and development of osteoarthritis (OA). It is challenging to protect articular cartilage and improve exercise when a meniscus injury occurs. Herein, inspired by the components and functions of the meniscus, we developed a self-lubricating and friction-responsive hydrogel that contains nanoliposomes loaded with diclofenac sodium (DS) and Kartogenin (KGN) for anti-inflammation and cartilage regeneration. When the hydrogel was injected into the meniscus injury site, the drug-loaded nanoliposomes were released from the hydrogel in a friction-responsive manner and reassembled to form hydration layers that lubricate joints during movement. Meanwhile, DS and KNG were constantly released from the nanoliposomes to mitigate inflammation and promote cartilage regeneration. Additionally, this hydrogel exhibited favorable injectability, mechanical properties, fatigue resistance, and prolonged degradation. In vivo experiments demonstrated that injection of the hydrogel effectively improved exercise performance and protected the articular cartilage of rats, suggesting it as a potential therapeutic approach for meniscal injuries.

Rapidly in situ forming an injectable Chitosan/PEG hydrogel for intervertebral disc repair.

Intervertebral disc (IVD) degeneration occurred with the increasing age or accidents has puzzled peoples in daily life. To seal IVD defect by injectable hydrogels is a promising method for slowing down IVD degeneration. Herein, we reported a rapidly in situ forming injectable chitosan/PEG hydrogel (CSMA-PEGDA-L) through integrating photo-crosslink of methacrylate chitosan (CSMA) with Schiff base reaction between CSMA and aldehyde polyethylene glycol (PEGDA). The CSMA-PEGDA-L possessed a stronger compressive strength than the photo-crosslinked CSMA-L hydrogel and Schiff-base-crosslinked CSMA-PEGDA hydrogel. This chitosan/PEG hydrogel showed low cytotoxicity from incubation experiments of nucleus pulpous cells. When implanted on the punctured IVD of rat's tail, the CSMA-PEGDA-L hydrogel could well retard the progression of IVD degeneration through physical plugging, powerfully proven by radiological and histological evaluations. This work demonstrated the strategy of in situ injectable glue may be a potential solution for prevention of IVD degeneration.

Research progress on the circRNA­mediated regulation of tumor angiogenesis through ceRNA mechanisms (Review).

Tumors are one of the most common fatal diseases worldwide and pose a severe threat to human health. Effective tumor prevention and treatment strategies are persistent challenges in the medical community. Angiogenesis plays a critical role in and is the basis for tumor development and metastasis. Circular RNAs (circRNAs) are novel single­stranded covalently closed RNA molecules that are widely expressed in tumors due to their structural specificity and conservation. circRNAs affect angiogenesis by functioning as microRNA sponges to regulate vascular endothelial growth factor­related pathways, thereby participating in various stages of tumor growth, invasion and proliferation. The present review summarizes the involvement of circRNAs in the regulation of tumor angiogenesis through competing endogenous RNA mechanisms, with a particular focus on the regulatory role of circRNAs in tumor angiogenesis in various systems. It is considered that circRNAs have great potential for use as tumor diagnostic markers and anti­angiogenic therapies, and are thus worthy of further research and exploration.

Genomic G-quadruplex folding triggers a cytokine-mediated inflammatory feedback loop to aggravate inflammatory diseases.

DNA G-quadruplex is a non-canonical secondary structure that could epigenetically regulate gene expression. To investigate the regulating role of G-quadruplex, we devised an integrating method to perform the algorithm profiling and genome-wide analysis for the dynamic change of genomic G-quadruplex and RNA profiles in rat nucleus pulposus cells by inducing G-quadruplex folding with multiple stabilizers. A group of genes potentially regulated by G-quadruplex and involved in the inflammation process has been identified. We found that G-quadruplex folding triggers inflammation response by upregulating inflammatory cytokines, which could promote G-quadruplex folding in a manner of positive feedback loop. Moreover, we confirmed that G-quadruplex is a marker indicating elevated inflammatory status and G-quadruplex folding facilitates the development of inflammatory diseases using in vivo intervertebral disc degeneration models. The crosstalk between G-quadruplex and inflammatory cytokines plays a vital role in regulating inflammation-derived diseases, which may provide new insights into the blocking target.

PRDX6: A protein bridging S-palmitoylation and diabetic neuropathy.

Diabetic neuropathy is regarded as one of the most debilitating outcomes of diabetes. It can affect both the peripheral and central nervous systems, leading to pain, decreased motility, cognitive decline, and dementia. S-palmitoylation is a reversible posttranslational lipid modification, and its dysregulation has been implicated in metabolic syndrome, cancers, neurological disorders, and infections. However, the role of S-palmitoylation in diabetic neuropathy remains unclear. Here we demonstrate a potential association between activating protein palmitoylation and diabetic neuropathy. We compared the proteomic data of lumbar dorsal root ganglia (DRG) of diabetes mice and palmitoylome profiling data of the HUVEC cell line. The mapping results identified peroxiredoxin-6 (PRDX6) as a novel target in diabetic neuropathy, whose biological mechanism was associated with S-palmitoylation. Bioinformatic prediction revealed that PRDX6 had two palmitoylation sites, Cys47 and Cys91. Immunofluorescence results indicated PRDX6 translocating between the cytoplasm and cell membrane. Protein function analysis proposed that increased palmitoylation could competitively inhibit the formation of disulfide-bond between Cys47 and Cys91 and change the spatial topology of PRDX6 protein. Cl-HCO3- anion exchanger 3 (AE3) was one of the AE family members, which was proved to express in DRG. AE3 activity evoked Cl- influx in neurons which was generally associated with increased excitability and susceptibility to pain. We demonstrated that the S-palmitoylation status of Cys47 could affect the interaction between PRDX6 and the C-terminal domain of AE3, thereby regulating the activity of AE3 anion exchanger enzyme in the nervous system. The results highlight a central role for PRDX6 palmitoylation in protection against diabetic neuropathy.

3D Printed Bioinspired Stents with Photothermal Effects for Malignant Colorectal Obstruction.

Stent placement is an effective palliation therapy for malignant colorectal obstruction. However, recurrent obstruction is a common severe complication caused by tumor ingrowth into the stent lumen. Conventional covered stents play a part in preventing the tumor from growing inward but at the expense of significantly increasing the risk of stent migration. Therefore, there is an urgent demand to develop stents with sustained antitumor and antimigration abilities. Herein, we propose a facile method for fabricating multifunctional bioinspired colorectal stents using 3D printing technology. Inspired by high-adhesion biological structures (gecko feet, tree frog toe pads, and octopus suckers) in nature, different types of bioinspired colorectal stents are designed to reduce migration. After functionalization with graphene oxide (GO), bioinspired colorectal stents show excellent and controllable photothermal performance, which is validated by effective ablation of colon cancer cells in vitro and tumors in vivo. Besides, the bioinspired colorectal stents demonstrate the feasibility of transanal placement and opening of the obstructed colon. More importantly, the facile manufacturing process of multifunctional bioinspired colorectal stents is appealing for mass production. Hence, the developed multifunctional bioinspired colorectal stents exhibit a highly promising potential in clinical applications.

PACT promotes the metastasis of basal-like breast cancer through Rac1 SUMOylation and activation.

Most basal-like breast cancers (BLBCs) are triple-negative breast cancers (TNBCs), which is associated with high malignancy, high rate of recurrence and distant metastasis, and poor prognosis among all types of breast cancer. However, there are currently no effective therapies for BLBC. Furthermore, chemoresistance limits the therapeutic options for BLBC treatment. In this study, we screen out protein activator of the interferon-induced protein kinase (PACT) as an essential gene in BLBC metastasis. We find that high PACT expression level was associated with poor prognosis among BLBC patients. In vivo and in vitro investigations indicated that PACT could regulate BLBC metastasis by interacting with SUMO-conjugating enzyme Ubc9 to stimulate the SUMOylation and thus consequently the activation of Rac1. BLBC patients receiving chemotherapy presents poorer prognosis with PACT high expression, and PACT disruption sensitizes experimental mammary tumor metastases to chemotherapy, thus providing insights to consider PACT as a potential therapeutic target to overcome acquired chemoresistance in BLBC.

The molecular mechanism of ferroptosis and its role in COPD.

Ferroptosis, a new type of cell death, is mainly characterized by intracellular iron accumulation and lipid peroxidation. The complex regulatory network of iron metabolism, lipid metabolism, amino acid metabolism, p53-related signaling, and Nrf2-related signaling factors is involved in the entire process of ferroptosis. It has been reported that ferroptosis is involved in the pathogenesis of neurological diseases, cancer, and ischemia-reperfusion injury. Recent studies found that ferroptosis is closely related to the pathogenesis of COPD, which, to some extent, indicates that ferroptosis is a potential therapeutic target for COPD. This article mainly discusses the related mechanisms of ferroptosis, including metabolic regulation and signaling pathway regulation, with special attention to its role in the pathogenesis of COPD, aiming to provide safe and effective therapeutic targets for chronic airway inflammatory diseases.

Intra-articular injection of loaded sPL sustained-release microspheres inhibits osteoarthritis and promotes cartilaginous repairs.

BACKGROUND: Osteoarthritis is a chronic inflammatory disease of the joints associated with significant morbidity and lower quality of life. Current treatment strategies focus on reducing cartilage degeneration but fail to restore their proliferative ability. Super-activated platelet lysate (sPL) is an enhanced form of platelet-rich plasma that can be easily inactivated. The purpose of this study is to evaluate whether sPL-loaded PLGA/chitosan/gelatin microspheres can prevent and treat osteoarthritis. METHODS: Features of biological microspheres were detected by SEM and ELISA. Osteoarthritis chondrocytes were co-cultured with hydrogel loaded with sPL. The effect of biological microspheres on chondrocyte proliferation was evaluated using a CCK-8 cell proliferation test. Cell morphology and cell necrosis were measured with a microscope. The gene expression levels of cartilage-related markers type 2 collagen, aggrecan (ACAN), and SRY type high mobility group box-9 (SOX9) were determined by real-time quantitative polymerase chain reaction (Rt-PCR). A rat osteoarthritis model was established. Micro-CT was used to characterize cartilaginous changes after the injection of biological microspheres. Histopathological HE staining, Safranin-O Fast Green staining and staining scores, type II collagen staining, and proteoglycan staining were used to evaluate the degree of cartilaginous repair. RESULTS: Biological microspheres were able to continuously release biological factors. Exposure to loading sPL microspheres significantly increased chondrocyte proliferation, reduced cell necrosis, and increased the expression of cartilage markers type 2 collagen, ACAN, and SOX9 in osteoarthritic chondrocytes. In vivo experiments found that biological microspheres also smoothen cartilage surfaces, promote the expression of proteoglycan and type 2 collagen while also increasing cartilaginous integrity as evaluated using Safranin-O Fast Green staining. CONCLUSIONS: PLGA/chitosan/gelatin hydrogel loaded with sPL is a promising tool for effective and non-invasive articular cartilage repair in osteoarthritis. Biological microspheres loaded with sPL release various biological factors to promote chondrocyte proliferation and upregulate chondrocyte functionalization genes (SOX9, CoX II, ACAN), leading to an overall enhanced cartilaginous matrix.

Therapeutic Study of Thermosensitive Hydrogel Loaded with Super-Activated Platelet Lysate Combined with Core Decompression Technology for the Treatment of Femoral Head Necrosis.

Super activated platelet lysate (sPL) is a derivative of platelet-rich plasma (PRP) that contains high levels of several growth factors. In this study, we synthesized a temperature-sensitive hydrogel that contained temperature-sensitive Poly(DL-lactide-glycolide-glycolide acid) (PLGA), SrCl2, and HA, and loaded it with different concentrations of sPL. The hydrogel showed satisfactory encapsulation efficiency and release of the growth factors in a sustained manner, indicating its suitability as a drug carrier. The sPL-loaded hydrogel was inserted into the necrotic femoral head of a rat model and core decompression was applied and resulted in significantly accelerated bone repair and regeneration. Therefore, encapsulation of sPL in a hydrogel scaffolding may be an effective strategy for treating femoral head necrosis.

Platelet-rich plasma attenuates intervertebral disc degeneration via delivering miR-141-3p-containing exosomes.

Oxidative stress mediated apoptotic and pyroptotic cell death contributes to intervertebral disc (IVD) degeneration, and platelet-rich plasma (PRP) exerts protective effects to attenuate IVD degeneration. Hence, the present study aimed to validate this issue and uncover the potential underlying mechanisms. The mice and cellular models for IVD degeneration were established by using puncture method and H2O2 exposure, respectively, and we evidenced that NLRP3-mediated cell pyroptosis, apoptosis and inflammatory responses occurred during IVD degeneration progression in vitro and in vivo. Then, the PRP-derived exosomes (PRP-exo) were isolated and purified, and we noticed that both PRP-exo and ROS scavenger (NAC) reversed the detrimental effects of H2O2 treatment on the nucleus pulposus (NP) cells. Further results supported that PRP-exo exerted its protective effects on H2O2 treated NP cells by modulating the Keap1-Nrf2 pathway. Mechanistically, PRP-exo downregulated Keap1, resulting in the release of Nrf2 from the Keap1-Nrf2 complex, which further translocated from cytoplasm to nucleus to achieve its anti-oxidant biological functions, and H2O2 treated NP cells with Nrf2-deficiency did not respond to PRP-exo treatment. In addition, miR-141-3p was enriched in PRP-exo, and miR-141-3p targeted the 3' untranslated region (3'UTR) of Keap1 mRNA for its degradation, leading to Nrf2 translocation. Furthermore, overexpression of miR-141-3p ameliorated the cytotoxic effects of H2O2 on NP cells, which were abrogated by upregulating Keap1 and silencing Nrf2. Taken together, we concluded that PRP secreted exosomal miR-141-3p to activate the Keap1-Nrf2 pathway, which helped to slow down IVD degeneration.

Ze-Qi-Tang Formula Induces Granulocytic Myeloid-Derived Suppressor Cell Apoptosis via STAT3/S100A9/Bcl-2/Caspase-3 Signaling to Prolong the Survival of Mice with Orthotopic Lung Cancer.

Non-small-cell lung cancer (NSCLC) remains the most common malignancy with the highest morbidity and mortality worldwide. In our previous study, we found that a classic traditional Chinese medicine (TCM) formula Ze-Qi-Tang (ZQT), which has been used in the treatment of respiratory diseases for thousands of years, could directly inhibit the growth of human NSCLC cells via the p53 signaling pathway. In this study, we explored the immunomodulatory functions of ZQT. We found that ZQT significantly prolonged the survival of orthotopic lung cancer model mice by modulating the tumor microenvironment (TME). ZQT remarkably reduced the number of MDSCs (especially G-MDSCs) and inhibited their immunosuppressive activity by inducing apoptosis in these cells via the STAT3/S100A9/Bcl-2/caspase-3 signaling pathway. When G-MDSCs were depleted, the survival promotion effect of ZQT and its inhibitory effect on lung luminescence signal disappeared in tumor-bearing mice. This is the first study to illustrate the immunomodulatory effect of ZQT in NSCLC and the underlying molecular mechanism.

Thevebioside, the active ingredient of traditional Chinese medicine, promotes ubiquitin-mediated SRC-3 degradation to induce NSCLC cells apoptosis.

Non-small cell lung cancer (NSCLC) accounts for more than 85% of lung cancer with high incidence and mortality. Accumulating studies have shown that traditional Chinese medicine (TCM) and its active ingredients have good anti-tumor activity. However, the anti-tumor effect of Thevebioside (THB), an active ingredient from TCM, is still unknown in NSCLC. In this study, to our best knowledge, it was the first time to report the underlying mechanism of its tumor-suppressive activity in NSCLC based on our previous high-throughput screening data. We further demonstrated that THB effectively inhibited the proliferation of NSCLC cells (A549 and H460) by inducing cellular apoptosis rather than cell cycle arrest. Notably, it was demonstrated that SRC-3 was significantly down-regulated after THB treatment dependent on ubiquitin-proteasome-mediated degradation, which subsequently inhibited the IGF-1R-PI3K-AKT signaling pathway and promoted apoptosis via both in vivo and in vitro experiments. Collectively, THB exerted inhibitory effect on tumor growth of NSCLC through inhibiting SRC-3 mediated IGF-1R-PI3K-AKT signaling by ubiquitination to induce cellular apoptosis with minimal toxicity no matter in vitro or vivo.

microRNA-1236 promotes chondrocyte apoptosis in osteoarthritis via direct suppression of PIK3R3.

AIMS: Chondrocyte degeneration is the main cause of osteoarthritis (OA) and increased evidence suggests that miRNAs could have vital roles in the pathology of various cartilage illnesses. miR-1236 has been found to contribute to inflammation in diseases such as pneumonia. However, the exact role of miR-1236 in OA is poorly understood. MATERIALS AND METHODS: H&E staining and saffron fixation experiments were employed to determine OA tissues. qRT-PCR and immunohistochemistry were used to detect the expression levels of miR-1236 and PIK3R3. Western blot was performed to detect the expression levels of proteins. Luciferase reporter assays were utilized to investigate the interaction between miR-1236 and PIK3R3. Cell counting assays and AO/EB were used to quantify cell growth and apoptosis. KEY FINDINGS: miR-1236 was up-regulated in OA knee cartilage compared to normal cartilage. Up-regulated expression of miR-1236 suppressed cell proliferation as well as induced apoptosis in chondrocytes. Bioinformatics identified PIK3R3 as a target of miR-1236. Co-transfection with miR-1236 and PIK3R3 could reverse cell apoptosis induced by the miR-1236 mimic. SIGNIFICANCE: These data enhance our understanding on the role of miR-1236 in OA and identifies miR-1236 as a potential biomarker or possible treatment target within OA.

Coaxial nanofiber scaffold with super-active platelet lysate to accelerate the repair of bone defects.

To develop biocomposite materials with the local sustained-release function of biological factors to promote bone defect repair, coaxial electrospinning technology was performed to prepare a coaxial nanofiber scaffold with super-active platelet lysate (sPL), containing gelatin/PCL/PLLA. The nanofibers exhibited a uniform bead-free round morphology, observed by a scanning electron microscope (SEM), and the core/shell structure was confirmed by a transmission electron microscope (TEM). A mixture of polycaprolactone and sPL encapsulated by hydrophilic gelatin and hydrophobic l-polylactic acid can continuously release bioactive factors for up to 40 days. Encapsulation of sPL resulted in enhanced cell adhesion and proliferation, and sPL loading can increase the osteogenesis of osteoblasts. Besides, in vivo studies demonstrated that sPL-loaded biocomposites promoted the repair of skull defects in rats. Therefore, these results indicate that core-shell nanofibers loaded with sPL can add enormous potential to the clinical application of this scaffold in bone tissue engineering.

The molecular mechanism of platelet lysate promotes transformation of non-union cells into osteoblasts.

BACKGROUND: Platelet lysate (PL) had a remarkable therapeutic effect on bone repair related diseases, such as delayed fracture healing, femoral head necrosis and meniscal tear. In this study, we investigated the effect of PL on patients with nonunion, cartilage repair and osteonecrosis, and to evaluate the effect of PL on nonunion cells proliferation and the effect of PL on OPG/RANKL signaling pathway in nonunion cell of male rats. To reveal the molecular mechanism of PL for bone healing. METHODS: We used different concentrations of PL to treat nonunion cells, then detected cell proliferation and protein expression levels of osteoprotegerin (OPG), RANKL, osteopontin (OPN), osteocalcin (OCN) and alkaline phosphatase (ALP). RESULTS: The proliferation rate of nonunion cells treated by 5% PL, was significantly higher than that of the control group (P<0.05). Surprisingly, there were no significant difference among the proliferation rates of nonunion cells treated by 8% PL, 10% FBS and the control group (P>0.05). the results of western blot analysis and immunofluorescence analysis showed that PL improved the expression of OPG, OPN, OCN and ALP proteins in nonunion cells, but PL had no effect on the expression of nuclear factor-κB ligand (RANKL) protein. CONCLUSIONS: We found that PL had a remarkable therapeutic effect on bone repair related diseases; 5% PL significantly improved the proliferation rate of the nonunion cells; 10% PL had a significantly positive effect on improving the expression levels of osteogenic related genes.

Identification and characterization of c-raf from orange-spotted grouper (Epinephelus coioides).

C-Raf proto-oncogene serine/threonine kinase is a mitogen-activated protein kinase (MAP) kinase kinase, which can initiate a mitogen-activated protein kinase (MAPK) cascade by phosphorylating the dual-specific MAP kinase kinases (MEK1/2), and in turn activate the extracellular signal-regulated kinases (ERK1/2). To study the function of c-Raf in teleost fish, a c-Raf cDNA sequence from orange-spotted grouper (Epinephelus coioides) was cloned. Ecc-Raf shared 81%-99% amino acid identity with other vertebrate c-Raf molecules, and shared the highest amino acid identity (99%) with Lates calcarifer c-Raf. Genomic structure analysis revealed that grouper c-Raf shared a conserved exon structure with other vertebrates. Tissue distribution showed that Ecc-Raf was mainly transcribed in systemic immune organs. Ecc-Raf was distributed throughout the cytoplasm of transfected GS cells and the overexpression of Ecc-Raf only slightly enhanced the activation of Activator protein 1. The phosphorylation levels of Ecc-Raf can be induced by PMA and H2O2 treatment, in contrast to DMSO or untreated HKLs. Moreover, the phosphorylation level of the Raf-MEK-ERK axis was downregulated after 24 h of SGIV infection. On the other hand, the total level and phosphorylation level of c-Raf significantly increased post C. irritans infection and showed an enhanced level post immunization. The results of this study suggested that the Raf-MEK-ERK cascade was involved in the response to viral or parasitic infections.

miR-590-3p is a novel microRNA which suppresses osteosarcoma progression by targeting SOX9.

Osteosarcoma is the most common primary bone malignancy and arises primarily in the metaphyseal ends of long bones in children and adolescents. m iR-590 has been found to have anti-tumor effects in many other cancers. However, the role of miR-590-3p in osteosarcoma is poorly understood. In this study, we show that miR-590-3p was significantly decreased both in osteosarcoma tissues and cell lines, suggesting a potential role of miR-590-3p in osteosarcoma. Over-expression of miR-590-3p inhibited U2OS cell viability as shown by the CCK-8 assay and clonogenic assay. Ki-67 immunofluorescence staining and cell cycle analysis revealed that up-regulation of miR-590-3p inhibited U2OS cell proliferation. Transfection with miR-590-3p mimics suppressed PCNA, Cyclin D1 and CDK4 expression and increased p53 and p21 expression. In addition, U2OS cells transfected with miR-590-3p mimics exhibited reduced cell invasion and migration, characterized by the wound healing assay and transwell assay. Furthermore, bioinformatics analysis demonstrated that SOX9 was a potential target of miR-590-3p. SOX9 was up-regulated in osteosarcoma tissues. Transfection with miR-590-3p mimics markedly suppressed SOX9 expression both at the mRNA level and protein level. Dual luciferase assay validated the direct binding site of miR-590-3p on SOX9. Exogenous SOX9 expression in U2OS cells at least partially reversed the effects of miR-590-3p in U2OS cells. Enforced SOX9 expression restored cell viability in osteosarcoma cells transfected with miR-590-3p mimics. In addition, over-expression of SOX9 restored decreased cell metastasis properties caused by transfection with miR-590-3p mimics in osteosarcoma cells. In summary, these results indicated that miR-590-3p is an anti-cancer miRNA that can inhibit proliferation and metastasis in osteosarcoma cells. Our findings provide a novel insight into the biological function of miR-590-3p in osteosarcoma and SOX9 may be a potential therapeutic target for osteosarcoma.