Positive Feedback Regulation of Circular RNA Hsa_circ_0000566 and HIF-1α promotes Osteosarcoma Progression and Glycolysis Metabolism.

Hypoxia is an indispensable factor for cancer progression and is closely associated with the Warburg effect. Circular RNAs (CircRNA) have garnered considerable attention in molecular malignancy therapy as they are potentially important modulators. However, the roles of circRNAs and hypoxia in osteosarcoma (OS) progression have not yet been elucidated. This study reveals the hypoxia-sensitive circRNA, Hsa_circ_0000566, that plays a crucial role in OS progression and energy metabolism under hypoxic stress. Hsa_circ_0000566 is regulated by hypoxia-inducible factor-1α (HIF-1α) and directly binds to it as well as to the Von Hippel-Lindau (VHL) E3 ubiquitin ligase protein. Consequentially, binding between VHL and HIF-1α is impeded. Furthermore, Hsa_circ_0000566 contributes to OS progression by binding to HIF-1α (while competing with VHL) and by confers protection against HIF-1α against VHL-mediated ubiquitin degradation. These findings demonstrate the existence of a positive feedback loop formed by HIF-1α and Hsa_circ_0000566 and the key role they play in OS glycolysis. Taken together, these data indicate the significance of Hsa_circ_0000566 in the Warburg effect and suggest that Hsa_circ_0000566 could be a potential therapeutic target to combat OS progression.

Typing characteristics of metabolism-related genes in osteoporosis.

Objective: Osteoporosis is a common musculoskeletal disease. Fractures caused by osteoporosis place a huge burden on global healthcare. At present, the mechanism of metabolic-related etiological heterogeneity of osteoporosis has not been explored, and no research has been conducted to analyze the metabolic-related phenotype of osteoporosis. This study aimed to identify different types of osteoporosis metabolic correlates associated with underlying pathogenesis by machine learning. Methods: In this study, the gene expression profiles GSE56814 and GSE56815 of osteoporosis patients were downloaded from the GEO database, and unsupervised clustering analysis was used to identify osteoporosis metabolic gene subtypes and machine learning to screen osteoporosis metabolism-related characteristic genes. Meanwhile, multi-omics enrichment was performed using the online Proteomaps tool, and the results were validated using external datasets GSE35959 and GSE7429. Finally, the immune and stromal cell types of the signature genes were inferred by the xCell method. Results: Based on unsupervised cluster analysis, osteoporosis metabolic genotyping can be divided into three distinct subtypes: lipid and steroid metabolism subtypes, glycolysis-related subtypes, and polysaccharide subtypes. In addition, machine learning SVM identified 10 potentially metabolically related genes, GPR31, GATM, DDB2, ARMCX1, RPS6, BTBD3, ADAMTSL4, COQ6, B3GNT2, and CD9. Conclusion: Based on the clustering analysis of gene expression in patients with osteoporosis and machine learning, we identified different metabolism-related subtypes and characteristic genes of osteoporosis, which will help to provide new ideas for the metabolism-related pathogenesis of osteoporosis and provide a new direction for follow-up research.

CircRNA circTIAM1 promotes papillary thyroid cancer progression through the miR-646/HNRNPA1 signaling pathway.

Papillary thyroid cancer (PTC) is a common endocrine tumor with a rapidly increasing incidence in recent years. Although the majority of PTCs are relatively indolent and have a good prognosis, a certain proportion is highly aggressive with lymphatic metastasis, iodine resistance, and easy recurrence. Circular RNAs (circRNAs) are a class of noncoding RNAs that are linked to a variety of tumor processes in several cancers, including PTC. In the current study, circRNA high-throughput sequencing was performed to identify alterations in circRNA expression levels in PTC tissues. circTIAM1 was then selected because of its increased expression in PTC and association with apoptosis, proliferation, and migration of PTC cells in vitro and in vivo. Mechanistically, circTIAM1 acted as a sponge of microRNA-646 and functioned in PTC by targeting miR-646 and heterogeneous ribonucleoprotein A1. Fluorescence in situ hybridization and dual-luciferase reporter assays further confirmed these connections. Overall, our results reveal an important oncogenic role of circTIAM1 in PTC and may represent a potentially therapeutic target against PTC progression.

Circular RNA circSIPA1L1 Contributes to Osteosarcoma Progression Through the miR-411-5p/RAB9A Signaling Pathway.

Recently, various studies have identified circular RNAs (circRNAs) to play a significant role in tumorigenesis, thereby showing potential as novel tumor biomarkers. circSIPA1L1 is a newly discoveredcircular RNA, which is formed by back-splicing of SIPA1L1 and is found increased in osteosarcoma (OS). Nevertheless, the specific functions of circSIPA1L1 in OS remain unknown. In the present study, circSIPA1L1 was obtained from a previously reported circRNA microarray in the GEO database (GSE96964). Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to assess the mRNA level of circSIPA1L1 in OS cell lines and tissue samples. Bioinformatics analysis, luciferase reporter assays, real-time PCR, RNA pull-down assays and RNA immunoprecipitation (RIP) were employed to verify the binding of circSIPA1L1 with miR-411-5p. Xenograft tumor models were established to identify the role of circSIPA1L1 in vivo. A series of in vitro experiments, such as western blotting, colony formation, transwell assays and anoikis assay were employed to confirm the relationship across circSIPA1L1, miR-411-5p, and RAB9A. Our study confirmed circSIPA1L1 to be upregulated in both human OS samples and OS cell lines. Mechanistically, circSIPA1L1 could serve as a miR-411-5p molecular sponge to increase RAB9A expression, which was confirmed to be a tumor promoter mediating carcinogenesis. Silencing of circSIPA1L1 attenuated the vitality, invasion, migration and proliferation of OS cell lines both in vivo and in vitro. miR-411-5p inhibition or RAB9A overexpression reversed the anti-tumor effects caused by circSIPA1L1 knockdown. Briefly, circSIPA1L1 could function as a driver gene in OS and initiate OS tumorigenesis through the miR-411-5p/RAB9A signaling pathway, which might become a potential therapeutic biomarker for OS treatment.

Acacetin Suppresses IL-1ß-Induced Expression of Matrix Metalloproteinases in Chondrocytes and Protects against Osteoarthritis in a Mouse Model by Inhibiting NF-κB Signaling Pathways.

Osteoarthritis (OA) is a very common chronic joint dysfunction, and there is currently a poor understanding of its etiology and pathogenesis. Therefore, there are no active disease-modifying drugs currently available for clinical treatment. Several natural compounds have been shown to play a role in inhibiting OA progression. The present study is aimed at investigating the curative effects of acacetin, a natural flavonoid compound, against OA. Our results demonstrated that MMP-1, MMP-3, and MMP-13 were highly expressed in OA specimens. Acacetin inhibited the interleukin-1ß- (IL-1ß-) induced expression of MMP-1, MMP-3, and MMP-13in chondrocytes by blocking nuclear factor-κB (NF-κB) signaling pathways. Furthermore, we found that acacetin suppressed OA progression and inhibited the expression of MMP-1, MMP-3, and MMP-13 in ACLT-induced OA mice. Taken together, our study revealed that acacetin may serve as a potential drug for treating OA.

Circular RNA circTUBGCP3 Is Up-Regulated and Promotes Cell Proliferation, Migration and Survivability via Sponge mir-30b in Osteosarcoma.

PURPOSE: Prevailing evidences have demonstrated that circular RNAs (circRNAs) are closely associated with various stages of carcinogenesis. However, very few studies have delineated the specific mechanism of association between circRNAs and osteosarcoma (OS). It offers a novel insight that circRNAs can be explored as a potential therapeutic strategy for OS. MATERIALS AND METHODS: In this study, circTUBGCP3 was chosen from the existing reported circRNA microarray data obtained from OS cell lines and normal bone cells. Subsequently, qRT-PCR was performed to evaluate the expression level of circTUBGCP3 in OS samples and cell lines. Functional assays were conducted to estimate the impact of circTUBGCP3 on human OS cells proliferation, vitality, survivability, and migration. Western blot, luciferase reporter and in vivo tumorigenesis assays were performed to analyze the signaling pathways underlying the interaction of circTUBGCP3, miR-30b, and Vimentin. RESULTS: The data indicate that circTUBGCP3 may act as a sponge of miR-30b that further alters the expression of Vimentin, and promotes the proliferation and metastatic properties of OS cells. CONCLUSION: circTUBGCP3 serves as a tumor promoter in tumorigenesis by increasing the possibilities of OS initiation and proliferation.

Circular RNA circTADA2A promotes osteosarcoma progression and metastasis by sponging miR-203a-3p and regulating CREB3 expression.

BACKGROUND: As a subclass of noncoding RNAs, circular RNAs (circRNAs) have been demonstrated to play a critical role in regulating gene expression in eukaryotes. Recent studies have revealed the pivotal functions of circRNAs in cancer progression. However, little is known about the role of circTADA2A, also named hsa_circ_0043278, in osteosarcoma (OS). METHODS: CircTADA2A was selected from a previously reported circRNA microarray comparing OS cell lines and normal bone cells. QRT-PCR was used to detect the expression of circTADA2A in OS tissue and cell lines. Luciferase reporter, RNA immunoprecipitation (RIP), RNA pull-down and fluorescence in situ hybridization (FISH) assays were performed to confirm the binding of circTADA2A with miR-203a-3p. OS cells were stably transfected with lentiviruses, and Transwell migration, Matrigel invasion, colony formation, proliferation, apoptosis, Western blotting, and in vivo tumorigenesis and metastasis assays were employed to evaluate the roles of circTADA2A, miR-203a-3p and CREB3. RESULTS: Our findings demonstrated that circTADA2A was highly expressed in both OS tissue and cell lines, and circTADA2A inhibition attenuated the migration, invasion and proliferation of OS cells in vitro as well as tumorigenesis and metastasis in vivo. A mechanistic study revealed that circTADA2A could readily sponge miR-203a-3p to upregulate the expression of CREB3, which was identified as a driver gene in OS. Furthermore, miR-203a-3p inhibition or CREB3 overexpression could reverse the circTADA2A silencing-induced impairment of malignant tumor behavior. CONCLUSIONS: CircTADA2A functions as a tumor promoter in OS to increase malignant tumor behavior through the miR-203a-3p/CREB3 axis, which could be a novel target for OS therapy.

CircSERPINE2 protects against osteoarthritis by targeting miR-1271 and ETS-related gene.

OBJECTIVES: Circular RNAs (circRNA) expression aberration has been identified in various human diseases. In this study, we investigated whether circRNAs could act as competing endogenous RNAs to regulate the pathological process of osteoarthritis (OA). METHODS: CircRNA deep sequencing was performed to the expression of circRNAs between OA and control cartilage tissues. The regulatory and functional role of CircSERPINE2 upregulation was examined in OA and was validated in vitro and in vivo, downstream target of CircSERPINE2 was explored. RNA pull down, a luciferase reporter assay, biotin-coupled microRNA capture and fluorescence in situ hybridisation were used to evaluate the interaction between CircSERPINE2 and miR-1271-5 p, as well as the target mRNA, E26 transformation-specific-related gene (ERG). The role and mechanism of CircSERPINE2 in OA was also explored in rabbit models. RESULTS: The decreased expression of CircSERPINE2 in the OA cartilage tissues was directly associated with excessive apoptosis and imbalance between anabolic and catabolic factors of extracellular matrix (ECM). Mechanistically, CircSERPINE2 acted as a sponge of miR-1271-5 p and functioned in human chondrocytes (HCs) through targeting miR-1271-5 p and ERG. Intra-articular injection of adeno-associated virus-CircSERPINE2-wt alleviated OA in the rabbit model. CONCLUSIONS: Our results reveal an important role for a novel circRNA-CircSERPINE2 in OA progression. CircSERPINE2 overexpression could alleviate HCs apoptosis and promote anabolism of ECM through miR-1271-ERG pathway. It provides a potentially effective therapeutic strategy for OA progression.

miR-10a-5p Promotes Chondrocyte Apoptosis in Osteoarthritis by Targeting HOXA1.

Osteoarthritis (OA) is a common joint disease characterized by degradation of the articular cartilage and joint inflammation. Studies have revealed the importance of microRNAs in the regulation of chondrocyte apoptosis. MicroRNA deep sequencing of control and osteoarthritic cartilage has revealed that miR-10a-5p is significantly upregulated in osteoarthritic tissues. However, its role in these tissues remains unknown. The present study was conducted to investigate the effect of miR-10a-5p in promoting OA. miR-10a-5p expression was increased in chondrocytes after interleukin-1ß treatment in vitro. Transfection with a miR-10a-5p inhibitor abrogated interleukin-1ß-induced apoptosis. A luciferase activity assay showed that miR-10a-5p targeted the 3' UTR of the homeobox gene HOXA1, inhibiting its expression. Treatment with HOXA1 siRNA reversed the rescuing effect of the miR-10a-5p inhibitor on chondrocyte apoptosis. Additionally, an OA model was established in mice by anterior cruciate ligament transection. AntagomiR-10a-5p improved the cartilage surfaces of osteoarthritic mice, whereas agomiR-10a-5p worsened them. A terminal deoxynucleotidyl transferase dUTP nick-end labeling assay indicated reduced apoptosis and increased HOXA1 expression in osteoarthritic mice after miR-10a-5p knockdown. These findings reveal a novel mechanism regulating OA progression and demonstrate the potential of miR-10a-5p and homeobox protein HOXA1 as therapeutic targets.

Pain Management by Nurses in Level 2 and Level 3 Hospitals in China.

BACKGROUND: Pain management practice differs among hospitals in China; however, no studies have examined the association between hospital level and nursing practice of pain management. AIMS: To evaluate the nursing practice of pain management in orthopedics wards of level 3 and 2 hospitals and compare the differences in pain management regulations, policies, and perceived barriers. DESIGN: This was a cross-sectional descriptive study. SETTING: This study was conducted during the 10th International Congress of the Chinese Orthopedic Association, November 19-22, 2015. PARTICIPANTS: Subjects: The sample included 121 nurses from China. METHODS: Quantitative research methods were used to assess pain management practice by 121 Chinese nurses as well as barriers to nursing practice. RESULTS: Nurses in level 3 hospitals were more likely to evaluate patients' pain intensity (85.23% vs. 65.38%, p < .05) and quality (77.27% vs. 53.85%, p < .05) than those in level 2 hospitals. Compared with level 2 hospitals, level 3 hospitals were more likely to participate in the Painless Orthopedics Ward program (53.41% vs. 23.08%, p < .01), conduct pain management knowledge training (88.64% vs. 69.23%, p < .05), and establish pain management regulations (68.18% vs. 34.62%, p < .01). Level 2 hospital nurses reported a higher score for barriers than level 3 hospital nurses (3.27 vs. 2.45, p < .05). CONCLUSIONS: Nurses from level 2 hospitals received less education on pain management and also paid less attention to and faced more restrictions for pain management than nurses from level 3 hospitals.

The Sensitivity of Orthopaedic Surgeons to the Secondary Prevention of Fragility Fractures.

BACKGROUND: Orthopaedic surgeons must play an important role in the secondary prevention of fragility fractures; however, some surgeons are more aware than others of their responsibility regarding fracture prevention. The purpose of the present study was to identify which factors can lead to a higher sensitivity for fracture prevention. METHODS: A cross-sectional survey was distributed to orthopaedic surgeons via online invitation or at academic conferences in China from July through October 2015. A total of 452 surgeons responded. As the primary outcome measure, we created a sensitivity scoring system for fracture prevention based on the respondents' answers to 5 questions regarding behavior in the following areas: risk-factor evaluation, pharmacologic therapy, nonpharmacologic therapy, patient education, and follow-up. Multivariable linear regression and multivariable logistic regression analyses were used to identify factors related to surgeon sensitivity to fracture prevention. RESULTS: Very few surgeons reported having received adequate training regarding fracture prevention or reading guidelines or other fracture prevention literature (22% and 30%, respectively). Most respondents initiated pharmacologic or nonpharmacologic therapy (82% and 75%, respectively) for the treatment of confirmed osteoporosis among patients with fragility fractures, but only half performed a risk-factor evaluation, patient education, or timely patient follow-up (51%, 52%, and 48%, respectively). In the multivariable linear regression model, the orthopaedic surgeon's age (ß = 0.09, p = 0.003), self-rated knowledge level regarding osteoporosis or related issues (ß = 0.16, p < 0.001), self-perceived effectiveness in using preventive measures for patients with a fragility fracture (ß = 0.62, p < 0.001), and use of clinical pathways for fragility fractures in his or her workplace (ß = 1.24, p < 0.001) were independently associated with sensitivity scores for fracture prevention. Similar results were obtained from a multivariable logistic regression model. CONCLUSIONS: In China, the sensitivity of orthopaedic surgeons to the secondary prevention of fragility fractures is relatively low. Implementation of a comprehensive prevention approach and targeted continuing medical education are required to encourage surgeons to take greater responsibility for screening, treating, educating, and following their patients with fragility fractures.

CircFAT1 sponges miR-375 to promote the expression of Yes-associated protein 1 in osteosarcoma cells.

BACKGROUND: There is an urgent need to identify new molecular targets for treatment of osteosarcoma. Circular RNAs are a class of endogenous RNAs that are extensively found in mammalian cells and exert critical functions in the regulation of gene expression, but in osteosarcoma the underlying molecular mechanism of circular RNAs remain poorly understood. Here we assessed the tumorigenesis properties of a circular RNA, circFAT1 in osteosarcoma. METHODS: The effects of circFAT1/miR-375/YAP1 was evaluated on human osteosarcoma cells growth, apoptosis, migration, invasion and tumorigenesis. Signaling pathways were analyzed by western blotting, qRT-PCR, fluorescence in situ hybridization, chromogenic in situ hybridization,RNA Binding Protein Immunoprecipitation and immunofluorescence. The consequence of circFAT1 short hairpin RNA combined or not with miR-375 sponge was evaluated in mice bearing 143B xenografts on tumor growth. RESULTS: In this study, we observed significant upregulation of circFAT1 originating from exon 2 of the FAT1 gene in human osteosarcoma tissues and cell lines. Inhibition of circFAT1 effectively prevented the migration, invasion, and tumorigenesis of osteosarcoma cells in vitro and repressed osteosarcoma growth in vivo. Mechanistic studies revealed that circFAT1 contains a binding site for the microRNA-375 (miR-375) and can abundantly sponge miR-375 to upregulate the expression of Yes-associated protein 1. Moreover, inhibition of miR-375 reversed attenuation of cell proliferation, migration, and invasion, which was induced by circFAT1 knockdown, and therefore promoted tumorigenesis. CONCLUSIONS: Our findings demonstrate a novel function of circFAT1 in tumorigenesis and suggest a new therapeutic target for the treatment of osteosarcoma.

Gambogic acid inhibits LPS-induced macrophage pro-inflammatory cytokine production mainly through suppression of the p38 pathway.

OBJECTIVES: In traditional Chinese medicine, gamboge can detoxify bodies, kill parasites, and act as a hemostatic agent. Recent studies have demonstrated that gambogic acid (GBA) suppressed inflammation in arthritis, and also presented antitumor effect. Thus, this study investigated the new biological properties of GBA on macrophages. MATERIALS AND METHODS: RAW 264.7 cells were pretreated with GBA at different concentrations (10, 20, 40, 80, 160, 320 nM) for 24 hrs, and then cell viability was measured using Cell Counting Kit (CCK)-8 assays. Pro-inflammatory cytokines such as TNF-α, IL-6 and IL-1ß were determined using ELISA kits and qPCR. Then nitrite concentration was calculated according to a standard curve. At last, the effect of GBA on MAPK and NF-κB signaling pathways was assessed by western blot and luciferase reporter gene assay. RESULTS: GBA (IC50: 260 nM) suppressed the TNF-α, IL-6 and IL-1ß expression induced by lipopolysaccharide (LPS) in RAW 264.7 cells. The expression of TNF-α, IL-6 and IL-1ß decreased to 30-50% and 70-75% in the high-dose (160 nM) and low-dose (40 and 80 nM) GBA groups, respectively. Furthermore, the nitric oxide (NO) production and the activation of NF-κB, ERK, and JNK pathways were significantly reduced in high-dose (160 nM) GBA only, while p38 pathway was inhibited at both low (40 and 80 nM) and high (160 nM) concentration of GBA. CONCLUSION: These data suggested that GBA inhibited LPS-induced production of pro-inflammatory cytokines including TNF-α, IL-6 and IL-1ß mainly through the suppression of the p38 pathway.

Ascorbic Acid Attenuates Multifidus Muscles Injury and Atrophy After Posterior Lumbar Spine Surgery by Suppressing Inflammation and Oxidative Stress in a Rat Model.

STUDY DESIGN: A rat model of multifidus muscles injury and atrophy after posterior lumbar spine surgery. OBJECTIVE: We determined the effect of ascorbic acid (AA) on the postoperative multifidus muscles in rat model. SUMMARY OF BACKGROUND DATA: Previous studies show oxidative stress and inflammation are two main molecular mechanisms in multifidus muscle injury and atrophy after posterior lumbar surgery. AA may have a protective effect in postoperative multifidus muscles. METHODS: Rats were divided into sham surgery, control surgery, and surgery plus AA groups. Multifidus muscles of the control and AA groups were excised from the osseous structures. The muscles were retracted continuously for 2 hours. In the sham and AA groups, AA was administered via oral gavage daily in the first week. In each group, the oxidative stress was evaluated by measuring malondialdehyde (MDA) and Total superoxide dismutase (T-SOD). The inflammation, fat degeneration, or fibrosis of multifidus muscle were evaluated by quantitative real-time polymerase chain reaction (q-PCR), histology, or immunohistochemical analysis. RESULTS: T-SOD activity was significantly lower in the control group than that in the AA group in the first week. MDA levels were significantly higher in the AA group. Interleukin-6 and tumor necrosis factor-α in multifidus muscles also showed significant differences when treated with AA. The inflammation score on histology was significantly lower in the AA group postoperatively in the first week. In the long run, marker genes for fibrosis and fat degeneration, and fibrosis and fat degeneration scores, were significantly lower in the AA than the control group on days 14 and 28 postoperatively. CONCLUSION: In conclusion, AA attenuated the oxidative stress and inflammation response in the postoperative multifidus muscles, and remarkable differences were observed from the histological assessment and related marker genes expression. Our results provided important insight into the anti-inflammatory and anti-oxidative effects of AA in the postoperative multifidus muscles. LEVEL OF EVIDENCE: N/A.

Honokiol alleviates the degeneration of intervertebral disc via suppressing the activation of TXNIP-NLRP3 inflammasome signal pathway.

Intervertebral disc degeneration (IVDD) is a multifactorial disease and responsible for many spine related disorders, causes disability in the workforce and heavy social costs all over the world. Honokiol, a low molecular weight natural product, could penetrate into and distribute in IVDs to achieve therapeutic effect in a rat tail model. Therefore, the present study was undertaken to examine the antiinflammatory, antioxidation and IVD-protective effect of honokiol using nucleus pulposus cells and investigate its mechanisms to provide a new basis for future clinical treatment of IVDD. In the current study, we demonstrated that honokiol inhibits the H2O2-induced apoptosis (caspase-9, caspase-3, and bax), levels of oxidative stress mediators (ROS, MDA), expression of inflammatory mediators (Interleukin-6, COX-2, and iNOS), major matrix degrading proteases (MMP-3, MMP-13, ADAMTS5, and ADAMTS4) associated with nucleus pulposus degradation. Furthermore, we found nucleus pulposus protective ability of honokiol by up-regulating extra cellular matrix anabolic factors like type II collagen (Col II) and SOX9 in nucleus pulposus. We also found that honokiol suppressed the phosphorylation of NF-kB and JNK, and activation of TXNIP-NLRP3 inflammasome in H2O2-stimulated nucleus pulposus cells, thereby inhibiting the activation of downstream inflammatory mediators such as Interleukin-1ß. Furthermore, honokiol showed a cartilage protective effect in the progression of IVDD in a rat model induced by puncture. Thus, our results demonstrate that honokiol inhibited the H2O2 induced apoptosis, oxidative stress, and inflammatory responses through the depression of TXNIP/NLRP3/caspase-1/ Interleukin - 1ß signaling axis and the activation of NF-kB and JNK. Honokiol possess nucleus pulposus protective properties and may be of value in suppressing the pathogenesis of IVDD.

Raddeanin A suppresses breast cancer-associated osteolysis through inhibiting osteoclasts and breast cancer cells.

Bone metastasis is a severe complication of advanced breast cancer, resulting in osteolysis and increased mortality in patients. Raddeanin A (RA), isolated from traditional Chinese herbs, is an oleanane-type triterpenoid saponin with anticancer potential. In this study, we investigated the effects of RA in breast cancer-induced osteolysis and elucidated the possible mechanisms involved in this process. We first verified that RA could suppress osteoclast formation and bone resorption in vitro. Next, we confirmed that RA suppressed Ti-particle-induced osteolysis in a mouse calvarial model, possibly through inhibition of the SRC/AKT signaling pathway. A breast cancer-induced osteolysis mouse model further revealed the positive protective effects of RA by micro-computed tomography and histology. Finally, we demonstrated that RA inhibited invasion and AKT/mammalian target of rapamycin signaling and induced apoptosis in MDA-MB-231 cells. These results indicate that RA is an effective inhibitor of breast cancer-induced osteolysis.

Lycorine Suppresses Endplate-Chondrocyte Degeneration and Prevents Intervertebral Disc Degeneration by Inhibiting NF-κB Signalling Pathway.

BACKGROUND/AIMS: Cartilaginous endplate (CEP) degeneration is an important cause for intervertebral disc (IVD) degeneration that leads to low-back pain. The identification of compounds that may prevent CEP degeneration is of interest for the prevention of IVD degeneration. METHODS: Catabolic protease expression in the CEP of disc degeneration patients was first assessed. The toxicity, function and underlying mechanism of lycorine (LY) on CEP-derived chondrocytes degeneration were assessed in vitro by flow cytometry analysis and western blotting. The concentration and function of LY in rat-tail disc-degeneration models were also assessed by HPLC (High Performance Liquid Chromatography) quantification and histological analysis. RESULTS: In CEP cells, Interleukin (IL)-1ß upregulated the expression of matrix metalloproteinase (MMP)-3, MMP-13, a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-4 and ADAMTS-5 that is critical for the degradation of cartilage extracellular matrix. Interestingly, LY suppressed the expression of these enzymes via the inhibition of nuclear factor-κB (NFκB) signalling and thus prevented IL-1ß-induced endplate cell degeneration in vitro. More importantly, LY also reduced the expression of MMP-3, MMP-13, ADAMTS-4 and ADAMTS-5 in CEP and exerted a protective effect on both CEP and nucleus pulposus (NP) degeneration. In addition to its inhibitory effect on matrix-degrading protease expression, LY treatment also reduced positive regulators of proinflammatory cytokines, such as MIF, which can be secreted by CEP cells and subsequently target NP cells. CONCLUSION: LY could serve as a potential drug for treating IVD disease.

Honokiol induces apoptosis and autophagy via the ROS/ERK1/2 signaling pathway in human osteosarcoma cells in vitro and in vivo.

Osteosarcoma is the most common primary malignant tumor of bone, the long-term survival of which has stagnated in the past several decades. In the present study, we investigated the anticancer effect of honokiol (HNK), an active component isolated and purified from the magnolia officinalis on human osteosarcoma cells. Our results showed that honokiol caused dose-dependent and time-dependent cell death in human osteosarcoma cells. The types of cell death induced by honokiol were primarily autophagy and apoptosis. Furthermore, honokiol induced G0/G1 phase arrest, elevated the levels of glucose-regulated protein (GRP)-78, an endoplasmic reticular stress (ERS)-associated protein, and increased the production of intracellular reactive oxygen species (ROS). In contrast, reducing production of intracellular ROS using N-acetylcysteine, a scavenger of ROS, concurrently suppressed honokiol-induced cellular apoptosis, autophagy, and cell cycle arrest. Consequently, honokiol stimulated phosphorylation of extracellular signal-regulated kinase (ERK)1/2. Furthermore, pretreatment of osteosarcoma cells with PD98059, an inhibitor of ERK1/2, inhibited honokiol-induced apoptosis and autophagy. Finally, honokiol suppressed tumor growth in the mouse xenograft model. Taken together, our results revealed that honokiol caused G0/G1 phase arrest, induced apoptosis, and autophagy via the ROS/ERK1/2 signaling pathway in human osteosarcoma cells. Honokiol is therefore a promising candidate for development of antitumor drugs targeting osteosarcoma.

FH535 Inhibits Proliferation and Motility of Colon Cancer Cells by Targeting Wnt/ß-catenin Signaling Pathway.

Aberrant Wnt/ß-catenin pathway activation is frequently observed in human colorectal cancer (CRC) and has become a promising target for CRC treatment. Our study aimed to evaluate the effect of FH535, a small molecule inhibitor of Wnt/ß-catenin pathway, on two colon cancer cell lines, HT29 and SW480. We found FH535 significantly inhibited colon cancer cell proliferation in vitro and induced cell cycle arrest. Moreover, FH535 inhibited colon cancer xenograft growth in vivo. Wound-healing assay and Transwell assay revealed that FH535 notably suppressed migration and invasion of SW480 cells. FH535 also repressed expression of cancer stem cell markers, CD24, CD44 and CD133 in HT29 cells. Real time-quantitative PCR and Western blotting revealed that targeting Wnt/ß-catenin pathway using FH535 effectively downregulated target genes including cyclin D1 and survivin at mRNA and protein level, which contributed to the FH535-induced inhibitory effect on colon cancer cell proliferation. As mechanisms for suppressing cancer cell motility, FH535 downregulated expression of matrix metalloproteinase-7 and -9, Snail and vimentin. RNA sequencing revealed that FH535 prominently altered multiple biological pathways associated with DNA replication, cell cycle and metabolism. Our study highlights the anti-cancer effect of FH535 on colon cancer and presents its potential in colon cancer treatment.

Sanguinarine protects against osteoarthritis by suppressing the expression of catabolic proteases.

Inflammatory cytokines play critical roles in the pathogenesis of osteoarthritis. Recent studies have demonstrated that natural active substances can serve as alternative therapeutic agents for the prevention and treatment of osteoarthritis. Sanguinarine, an alkaloid isolated from the roots of Sanguinaria canadensis, is known to have anti-inflammatory properties. The aim of the present study was to investigate the therapeutic effect of Sanguinarine against osteoarthritis. Sanguinarine inhibited interleukin-1ß-induced expression of matrix metalloproteinase 1, 3, and 13, and A disintegrin and metalloproteinase with thrombospondin motifs-5 in chondrocytes, which involved the nuclear factor-κB and c-Jun N-terminal kinase signalling pathways. Furthermore, the study of interleukin-1ß-induced cartilage matrix degradation in an anterior cruciate ligament transection-induced osteoarthritis model revealed that Sanguinarine ameliorated osteoarthritis by inhibiting the expression of matrix metalloproteinase 1, 3, and 13, and A disintegrin and metalloproteinase with thrombospondin motifs-5. In conclusion, we demonstrated for the first time that Sanguinarine suppressed the expression of matrix metalloproteinase 1, 3, and 13, and A disintegrin and metalloproteinase with thrombospondin motifs-5 in vitro, ex vivo, and in vivo, indicating its potential usefulness in treating osteoarthritis.