Growth Of Human Osteosarcoma Cells Research Articles

RNF135 Promotes Human Osteosarcoma Cell Growth and Inhibits Apoptosis by Upregulating the PI3K/AKT Pathway.

Ring finger protein 135 (RNF135) is an E3 ubiquitin ligase that has been implicated in the tumorigenesis of multiple human malignancies. However, whether RNF135 plays a role in the development of human osteosarcoma (OS) remains unknown. RNF135 expression in 20 human OS and 20 human osteochondroma specimens were evaluated by means of immunohistochemistry staining. The effects of shRNA-mediated RNF135 knockdown on human OS cell growth and apoptosis were evaluated through a panel of in vitro studies on cell proliferation, colony formation, exposure of phosphatidylserine on the cell surface, and caspase 3/7 activation. The protein levels of PI3K, AKT, and p-AKT were determined by western blot analysis. We detected significantly higher RNF135 levels in human OS tissues than human osteochondroma tissues. In in vitro studies, shRNA-mediated RNF135 knockdown in human OS cells inhibited proliferation and induced apoptosis. In addition, RNF135 knockdown reduced PI3K and p-AKT protein levels and activated caspase 3 and 7. These results supported that RNF135 contributes to human OS development through PI3K/AKT-dependent mechanisms. Targeting RNF135 may provide a new therapeutic approach for treating this human malignancy.

Polyphyllin I enhances tumor necrosis factor-related apoptosis-inducing ligand-induced inhibition of human osteosarcoma cell growth downregulating the Wnt/β-catenin pathway.

To investigate the synergistic effects of polyphyllin I (PPI) combined with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) on the growth of osteosarcoma cells through downregulating the Wnt/β-catenin signaling pathway. Cell viability, apoptosis and cell cycle distribution were examined using cell counting kit-8 and flow cytometry assays. The morphology of cancer cells was observed with inverted phase contrast microscope. The migration and invasion abilities were examined by xCELLigence real time cell analysis DP system and transwell assays. The expressions of poly (adenosine diphosphate-ribose) polymerase, C-Myc, Cyclin B1, cyclin-dependent kinases 1, N-cadherin, Vimentin, Active-β-catenin, β-catenin, p-glycogen synthase kinase 3β (GSK-3β) and GSK-3β were determined by Western blotting assay. PPI sensitized TRAIL-induced decrease of viability, migration and invasion, as well as increase of apoptosis and cell cycle arrest of MG-63 and U-2 OS osteosarcoma cells. The synergistic effect of PPI with TRAIL in inhibiting the growth of osteosarcoma cells was at least partially realized through the inactivation of Wnt/β-catenin signaling pathway. The combination of PPI and TRAIL is potentially a novel treatment strategy of osteosarcoma.

Synthesized tin oxide nanoparticles promote apoptosis in human osteosarcoma cells

Complicated protocols have been used to tune the size of tin oxide nanoparticles (SnO2 NPs) in conventional chemical synthesis approaches. In this study, we addressed this issue through the combination of polarity solvent reduction and sonication as a potential strategy for optimizing the size of SnO2 NPs for anticancer applications. Then the anticancer activity and safety of synthesized SnO2 NPs on U-2OS human osteosarcoma cells and normal human osteoblast, NHOst, respectively, were assessed by several assays. SEM and TEM analyses revealed that synthesized SnO2 NPs had a spherical-shaped morphology with an average particle size of about 10 nm. FTIR result showed a broad absorption peak at 649 cm– 1, corresponding to the stretching vibration of the O–Sn–O bond. XRD analysis exhibited eight main peaks, revealing a tetragonal system of rutile-like structure. DLS study showed that synthesized SnO2 NPs had an average hydrodynamic size of 43.93 nm with a zeta potential value of −31.00 mV. Cellular assays displayed that SnO2 NPs mitigate the growth of U-2OS human osteosarcoma cells (IC50: 15.50 µg/mL) with partial cytotoxicity on normal osteoblasts. It was then discovered that SnO2 NPs triggered stress effects by raising the levels of LDH release, ROS, and MDA and lowering those of SOD, CAT activity, and GSH content. Also, it was discovered that SnO2 NPs activated both intrinsic and extrinsic signaling pathways mediated by MMP collapse, elevation of caspase-3, −9, −8 activities and corresponding mRNA, and upregulation of Bax/Bcl-2 mRNA ratio. Overall, this study found that extrinsic and mitochondrial apoptotic pathways can both be activated by synthesized SnO2 NPs to induce apoptosis in human osteosarcoma cells. This finding calls for additional research in the future.

Asiatic acid affects the growth of human osteosarcoma cells by regulating PI3K/AKT and NF-κB dual signal pathways

Osteosarcoma(OS) is a common primary malignant bone tumor, which mostly occurs in children and adolescents. Currently, chemotherapy drugs for the clinical treatment of OS have high side effects and patients are prone to chemotherapy resistance, which reduces the therapeutic effect. Therefore, the development of new therapeutic drugs is very important to reduce the toxicity and adverse reactions of drugs and improve the survival rate of patients. At present, the antitumor activity of traditional Chinese medicine monomers has received extensive attention because of its safety and efficacy. Asiatic acid (AA) is a naturally pentacyclic triterpenoids extracted from Centella asiatica. The aim of this study was to evaluate the effect and mechanism of AA on OS cells in vitro and in vivo. In vitro results showed that AA inhibited the proliferation, migration and invasion of OS cells and was able to induce apoptosis and cycle arrest. In vivo results showed that AA inhibited the growth of OS and the size of lung metastasis in nude mice. Network pharmacology, molecular docking and in vitro experiments prove that AA may play a role in the treatment of OS by inhibiting PI3K/AKT and NF-κB signaling pathways. Our study shows that AA can act on multiple targets of OS and regulate multiple pathways to intervene in the occurrence and development of OS, which may provide reference for the clinical application and development of AA.

MicroRNA-196-5p targets Derlin-1 to induce autophagy in human osteosarcoma cells

Osteosarcoma is a highly prevalent type of primary bone tissues in children and young adolescents. Micro-RNA (miR) dysregulation has been linked to osteosarcoma tumorigenesis. The role of miR-196-5p was investigated in modulating the growth and metastatic behaviour of human osteosarcoma cells, along with exploring its mechanism of action. As shown by RT-qPCR expression analysis, osteosarcoma cell lines exhibited prominent (P<0.05) transcriptional repression of miR-196-5p. The latter was thus transiently overexpressed in osteosarcoma cells, which resulted in the loss of cell viability and colony formation via induction of autophagy. The western blot analysis of the autophagy marker proteins revealed that the expression of Beclin 1 and LC3B II proteins was induced by miR-196-5p, whereas that of p62 and LC3BI was repressed. Moreover, osteosarcoma cells overexpressing miR-196-5p showed significantly (P<0.05) lower migration and invasion concerning the control osteosarcoma cells. According to the results of the in-silico analysis, Derlin-1 participates in the regulation of miR-196-5p in osteosarcoma, and this prediction has been validated using a dual luciferase assay. The results indicated that miR-196-5p exerted its molecular role by targeting Derlin-1 at the post-transcriptional level. Summing up, the study revealed the modulatory potential of miR-196-5p/Derlin-1 on osteosarcoma cells and provided insights into the possible implications for the treatment and prognosis of the disease.

Echinatin inhibits the growth and metastasis of human osteosarcoma cells through Wnt/β-catenin and p38 signaling pathways

Osteosarcoma (OS) is a highly aggressive malignant bone tumor that mainly occurs in adolescents. At present, chemotherapy is the most commonly used method in clinical practice to treat OS. However, due to drug resistance, toxicity and long-term side effects, chemotherapy can’t always provide sufficient benefits for OS patients, especially those with metastasis and recurrence. Natural products have long been an excellent source of anti-tumor drug development. In the current study, we evaluated the anti-OS activity of Echinatin (Ecn), a natural active component from the roots and rhizomes of licorice, and explored the possible mechanism. We found that Ecn inhibited the proliferation of human OS cells and blocked cell cycle at S phase. In addition, Ecn suppressed the migration and invasion, while induced the apoptosis of human OS cells. However, Ecn had less cytotoxicity against normal cells. Moreover, Ecn inhibited the xenograft tumor growth of OS cells in vivo. Mechanistically, Ecn inactivated Wnt/β-catenin signaling pathway while activated p38 signaling pathway. β-catenin over-expression and the p38 inhibitor SB203580 both attenuated the inhibitory effect of Ecn on OS cells. Notably, we demonstrated that Ecn exhibited synergistic inhibitory effect with cisplatin (DDP) on OS cells in vitro and in vivo. Therefore, our results suggest that Ecn may exert anti-OS effects at least partly through regulating Wnt/β-catenin and p38 signaling pathways. Most meaningfully, the results obtained suggest a potential strategy to improve the DDP-induced tumor-killing effect on OS cells by combining with Ecn.

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

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

Neferine inhibits the growth of human osteosarcoma cells through activating P38/JNK and suppressing Wnt/β-catenin signaling pathway

Osteosarcoma (OS) is one of the most common types of bone malignant tumors. Clinical commonly used therapeutic drugs of OS treatment are prone to toxic and side effects, so it is supposed to develop new drugs with low toxicity and low side effects. As a Chinese traditional medicine, Neferine(C38H44N2O6) has inhibitory effects in various tumors. In the present study, we investigated the effects of Nef on OS cells in vitro and in vivo. We found that Nef inhibited cell proliferation, reduced migration, decreased invasion, and induced cell cycle arrest of OS cells. Notably, we demonstrated that Nef had no obvious effect on proliferation and apoptosis of normal cells. Besides, Nef repressed tumor growth of OS cells in xenograft mouse model. Mechanically, we found that Nef increased the phosphorylation level of P38 and JNK and suppressed Wnt/β-Catenin signaling pathway. In summary, our research validates that Nef may inhibit the proliferation, migration, and invasion of OS and promote apoptosis possibly by activating P38/JNK and suppressing Wnt/β-Catenin signaling pathway.

Andrographolide inhibits the growth of human osteosarcoma cells by suppressing Wnt/β-catenin, PI3K/AKT and NF-κB signaling pathways

Osteosarcoma (OS) is an aggressive malignant skeletal tumor characterized by an extremely poor prognosis and a high tendency to recur. The frequently used anti-OS chemotherapy regents are often limited by drug resistance and severe adverse events. It is urgent to develop more effective, tolerable and safe drugs for the treatment of OS. Andrographolide (AG), a diterpenoid lactone isolated from Andrographis paniculata, has been proved to possess anti-tumor activity against several human cancer types. In this current study, we evaluated the inhibitory effect of AG on human OS cells and probed the possible mechanism. We found that AG inhibited the proliferation of human OS cells and blocked cell cycle at G2/M phase. Furthermore, AG impeded the migration and invasion, while promoted the apoptosis of human OS cells. Moreover, we found that AG inhibited OS growth and lung metastasis in orthotopic transplantation model. Mechanistically, we demonstrated that AG suppressed the activity of Wnt/β-catenin, PI3K/AKT and NF-κB signaling pathways. Notably, we validated that AG synergized with the inhibitors of Wnt/β-catenin, PI3K/AKT and NF-κB to suppress the proliferation, migration and invasion of human OS cells. Collectively, our study conclusively demonstrates that AG inhibits the growth of human OS cells, thus, may be a promising candidate for the treatment of OS.

Long non-coding RNA MINCR regulates the growth and metastasis of human osteosarcoma cells via Wnt/β-catenin signaling pathway.

There is concrete evidence that lncRNA-MINCR is involved in tumorigenesis of a number of human cancers through modulation of Wnt/β-catenin signaling pathway. However, the characterization of regulatory role of lncRNA-MINCR has not been worked out in osteosarcoma yet. The present study was undertaken to explore the role of lncRNA-MINCR in human osteosarcoma. The osteosarcoma tissues and cell lines were found to exhibit significant (P<0.05) over-expression of lncRNA-MINCR. Silencing of lncRNA-MINCR in osteosarcoma cells suppressed their cell viability through the induction of apoptosis. The Saos-2 osteosarcoma cells exhibited significant (P<0.05) decline in migration and invasion rate together with inhibition of EMT under transcriptional knockdown of lncRNA-MINCR. Western blot analysis revealed that lncRNA-MINCR operated through Wnt/β-catenin signaling pathway to control the growth and metastasis of osteosarcoma cells. In vivo mice tumorigenesis was significantly (P<0.05) restricted under lncRNA-MINCR repression. The study clearly indicated that lncRNA-MINCR exhibits crucial growth regulatory role in osteosarcoma together with its ability to control the metastasis of cancer cells through Wnt/β-catenin signal.

Acacetin inhibits the tumor growth of human osteosarcoma cells through regulating Wnt/β-catenin and JNK signaling pathways

• Acacetin weakens the proliferation, migration and invasion of osteosarcoma cells. • Acacetin promotes the apoptosis of osteosarcoma cells. • Xenograft mouse osteosarcoma model confirms the inhibitory effect in vivo . • The signal pathway is predicted by network pharmacology and confirmed by the experiments. Osteosarcoma (OS) is the most common primary malignant bone tumor with high lung metastasis and mortality rate. Neo-adjuvant chemotherapy combined with limb salvage is the main treatment strategy for OS. However, because of the tolerance to conventional chemotherapy and the cell toxicity of chemotherapy drugs, new drugs with lower toxicity for OS are urgently needed. Acacetin is a natural flavonoid compound that has inhibitory effects on many kinds of tumors. Herein, we explored the impact of acacetin on OS cell growth in vitro and in vivo . We discovered that acacetin suppressed the proliferation, migration and invasion, while promoted the apoptosis of OS cells. Notably, acacetin had little impact on proliferation and apoptosis of human normal cells. Furthermore, we confirmed that acacetin repressed the growth and metastasis of OS in xenograft mouse model in vivo . Mechanically, we discovered that acacetin activated JNK pathway and inactivated Wnt/β-catenin pathway. β-catenin over-expression or JNK inhibitor SP600125 was able to partially neutralize acacetin-induced inhibitory effect on OS cells. To sum up, our study implies that acacetin may inhibit tumor growth of human OS cells through regulating Wnt/β-catenin and JNK signaling pathways.

Application of Novel Nano-Hydroxyapatite in Proliferation and Apoptosis of Human Osteosarcoma Cells

In this study, the purpose is to examine the impact of nano-hydroxyapatite (Nano-HAP) on human osteosarcoma cell (U2OS) growth and apoptosis (cell death). For reaching this goal an apoptosis kit was employed to determine the influence of Nano-HAP on apoptosis in human osteosarcoma cells U2OS, which were treated with different doses of Nano-HAP; FDA staining was used to elucidate the effect of Nano-HAP on cell adhesion. U2OS adhesion was not affected by Nano-HAP at different concentrations, however the production of U2OS was dramatically reduced. U2OS osteosarcoma cell growth was considerably inhibited at the doses of 50 g/ml and 800 g/ml, respectively. In conclusion, osteosarcoma cell growth and apoptosis are greatly inhibited by nano-HAP, although there is no clear linear link between nanoparticle concentration and the impact.

MicroRNA-181a-5p Promotes Osteosarcoma Progression via PTEN/AKT Pathway.

Osteosarcoma is the most common primary malignant bone tumor in children and adolescents with poor prognosis. MicroRNA-181a-5p (miR-181a-5p) is involved in the progression of various tumors; however, its role and underlying mechanism in osteosarcoma remains unclear. In this study, we found that miR-181a-5p was upregulated in human osteosarcoma cells and tissues. miR-181a-5p mimic significantly promoted, while miR-181a-5p inhibitor blocked the proliferation, colony formation, migration, invasion, and cell cycle progression of osteosarcoma cells. Mechanistically, miR-181a-5p bound to the 3′-untranslational region of phosphatase and tensin homolog (PTEN) and reduced its protein expression, thereby activating protein kinase B (PKB/AKT) pathway. Either PTEN overexpression or AKT inhibition notably blocked the tumor-promoting effects of miR-181a-5p. Moreover, we observed that miR-181a-5p mimic further inhibited growth of human osteosarcoma cells in the presence of adriamycin or cisplatin. Overall, miR-181a-5p promotes osteosarcoma progression via PTEN/AKT pathway and it is a promising therapeutic target to treat osteosarcoma.

Combined bezafibrate, medroxyprogesterone acetate and valproic acid treatment inhibits osteosarcoma cell growth without adversely affecting normal mesenchymal stem cells.

Drug repurposing is a cost-effective means of targeting new therapies for cancer. We have examined the effects of the repurposed drugs, bezafibrate, medroxyprogesterone acetate and valproic acid on human osteosarcoma cells, i.e., SAOS2 and MG63 compared with their normal cell counterparts, i.e. mesenchymal stem/stromal cells (MSCs). Cell growth, viability and migration were measured by biochemical assay and live cell imaging, whilst levels of lipid-synthesising enzymes were measured by immunoblotting cell extracts. These drug treatments inhibited the growth and survival of SAOS2 and MG63 cells most effectively when used in combination (termed V-BAP). In contrast, V-BAP treated MSCs remained viable with only moderately reduced cell proliferation. V-BAP treatment also inhibited migratory cell phenotypes. MG63 and SAOS2 cells expressed much greater levels of fatty acid synthase and stearoyl CoA desaturase 1 than MSCs, but these elevated enzyme levels significantly decreased in the V-BAP treated osteosarcoma cells prior to cell death. Hence, we have identified a repurposed drug combination that selectively inhibits the growth and survival of human osteosarcoma cells in association with altered lipid metabolism without adversely affecting their non-transformed cell counterparts.

Tetrandrine suppresses the growth of human osteosarcoma cells by regulating multiple signaling pathways

ABSTRACT Although osteosarcoma (OS) is the most common malignant tumor among juvenile bone tumors, its treatment plan and clinical outcome have not improved significantly in recent decades. Tetrandrine (TET), a Chinese medicine that is usually used in the therapy of silicosis, hypertension and arthritis, has been confirmed by many studies to possess potent antitumour growth properties, but there are different limitations when describing specific mechanisms. Here, we found that TET can obviously prevent the proliferation, migration and invasion of both 143B and MG63 cells and promote their apoptosis in vitro. Our results for luciferase reporter and Western blotting assays show that TET may exert its antitumour activity by regulating multiplex signaling pathways, including the MAPK/Erk, PTEN/Akt, Juk and Wnt signaling pathways. Furthermore, the regulatory effect of TET on OS cells and related signaling pathways was verified again in vivo. Our findings suggest that the anticancer function of TET on human OS may be mediated by its targeting of multiple signaling pathways and that TET may be used as a single drug or in combination with other drugs during the treatment of OS.

MiRNA-1225 Inhibits Osteosarcoma Tumor Growth and Progression by Targeting YWHAZ.

IntroductionOsteosarcoma is the most common bone tumor and is characterized by the presence of malignant mesenchymal cells produced in the bone stroma. MiRNAs are known to function as post-transcriptional negative regulators of gene expression. Emerging evidence showed that miR-1225-5P functions as a tumor suppressor in several types of cancers. The detailed mechanisms of which miR-1225-5P suppresses tumor growth are not fully understood. The objective of the present study was to test the hypothesis that miR-1225-5P inhibits osteosarcoma cell growth in vitro and tumor growth in vivo by targeting YWHAZ expression.MethodsReal-time PCR and Western blot were carried out to test the expression of miR-1225-5P and YWHAZ in osteosarcoma cell lines. Luciferase assay was used to demonstrate whether miR-1225-5P targets YWHAZ 3ʹ UTR. To assess the function of miR-1225-5P in human osteosarcoma cell lines, gain-of-function and loss-of-function of miR-1225-5P were performed by transfecting miR-1225-5P mimic or miR-1225-5P inhibitor into osteosarcoma cell lines. Furthermore, cell cycle analysis was performed to elucidate the possible mechanisms of the action of miR-1225-5P and YWHAZ in human osteosarcoma cells. The potential therapeutic effect of miR-1225-5p was tested in human osteosarcoma xenograft mouse model, by intravenous injection of miR-1225-5P into nude mice. Tumor sizes were measured and lung metastasis was counted after the mice were sacrificed.ResultsThe expression of miR-1225-5P was inversely correlated with the expression of YWHAZ in human osteosarcoma cell lines. Database search revealed that miR-1225-5P targeted YWHAZ 3ʹ UTR. Transfection of miR-1225-5P mimic downregulated YWHAZ expression, which was demonstrated by real-time PCR, Western blot and luciferase assay. Over-expression of miR-1225-5P reduced human osteosarcoma cell growth, migration and invasion by downregulating YWHAZ expression. Cell growth, migration and invasion were increased by inhibiting miR-1225-5P in human osteosarcoma cells. The inhibition of cell growth, migration and invasion was rescued by over-expression of YWHAZ in osteosarcoma cells. Cell cycle analysis revealed that miR-1225-5P inhibited G1/G0 phase exit. In vivo xenograft model demonstrated that miR-1225-5P inhibited in vivo osteosarcoma tumor growth and lung metastasis.ConclusionOur findings suggested that miR-1225-5P inhibits osteosarcoma cell growth in vitro and tumor growth in vivo by targeting YWHAZ. This study suggested that miR-1225-5P can serve as a potential therapeutic method for treating osteosarcoma.

Cardamonin inhibits the growth of human osteosarcoma cells through activating P38 and JNK signaling pathway

Osteosarcoma (OS) is the most common type of bone malignant tumors. Clinical commonly used therapeutic drugs of OS treatment are prone to toxic and side effects, so it is very urgent to develop new drugs with low toxicity and low side effects. As a Chinese herbal medicine, Cardamonin (CAR) (C16H14O4) has inhibitory effects in various tumors. In the present study, we investigated the effects of CAR on OS cells in vitro and in vivo. We found that CAR inhibited cell proliferation, reduced migration, decreased invasion, and induced G2 / M arrest of OS cells. Notably, we demonstrated that CAR had no obvious effect on proliferation and apoptosis of normal cells. Besides, CAR repressed tumor growth of OS cells in xenograft mouse model. Mechanically, we found that CAR increased the phosphorylation level of P38 and JNK. In summary, our research validates that CAR may inhibit the proliferation, migration, and invasion of OS and promote apoptosis possibly by activating P38 and JNK Mitogen-activated protein kinase (MAPK) signaling pathway.

VS-5584 Inhibits Human Osteosarcoma Cells Growth by Induction of G1- phase Arrest through Regulating PI3K/mTOR and MAPK Pathways.

Activation of the PI3K/mTOR signaling pathway plays a key role in the progression of human osteosarcoma. Studies have confirmed that VS-5584 was a novel inhibitor of the PI3K/mTOR pathway, and displayed potential anticancer activity. To explore the anticancer effect and underlying mechanism of VS-5584 against the growth of human osteosarcoma cells. U2OS and MG-63 human osteosarcoma cells were cultured and the cytotoxicity, cell apoptosis in VS-5584-treated cells were explored by the CCK8 assay, flow cytometric analysis and western blot. Cell migration and tube formation were also employed to examine the anticancer potential. The results showed that VS-5584 treatment dose-dependently inhibited the growth of U2OS and MG-63 cells by induction of G1-phase arrest through regulating p21, p27, Cyclin B1 and Cdc2. Further investigation revealed that VS-5584 treatment effectively inhibited the PI3K/mTOR signaling pathway and triggered MAPK phosphorylation. Moreover, VS-5584 treatment dramatically suppressed cell migration and tube formation of HUVECs, followed by the down-regulation of HIF-1α and VEGF. Our findings validated that VS-5584 may be a promising anticancer agent with potential application in the chemotherapy and chemoprevention of human osteosarcoma.

CCT128930 induces G1-phase arrest and apoptosis and synergistically enhances the anticancer efficiency of VS5584 in human osteosarcoma cells

Osteosarcoma is a highly invasive primary malignant bone tumor. PI3K/mTOR pathway plays a key role in tumor progression, and inhibition of PI3K/mTOR pathway represents a novel strategy in therapy of osteosarcoma. CCT128930 and VS5584 are both inhibitors of PI3K/mTOR, but the anticancer mechanism of CCT128930 or/and VS5584 against human osteosarcoma cells remains unclear. Herein, U2OS and MG63 human osteosarcoma cells were cultured, and the anticancer effects of CCT128930 alone and the combined effect of CCT128930 and VS5584 against human osteosarcoma cells were explored. The results showed that CCT128930 as PI3K/mTOR inhibitor effectively inhibited p-p70 and p-AKT expression and dose-dependently inhibited U2OS cells and MG63 human osteosarcoma cells growth. Further studies found that CCT128930 triggered significant G-1 phase arrest and apoptosis, as convinced by the dysfunction of p27, Cyclin B1, Cyclin D1 and Cdc2, and PARP cleavage and caspase-3 activation. Moreover, CCT128930 treatment obviously enhanced VS5584-induced growth inhibition and apoptosis in human osteosarcoma cells, followed by enhanced PARP cleavage and caspase-3 activation. Taken together, CCT128930 alone or combined treatment with CCT128930 and VS5584 both effectively inhibited human osteosarcoma cells growth by induction of G1-phase arrest and apoptosis through regulating PI3K/mTOR and MAPKs pathways.

Mangiferin suppresses human metastatic osteosarcoma cell growth by down-regulating the expression of metalloproteinases-1/2 and parathyroid hormone receptor 1

The study evaluates the protective effect of mangiferin on osteosarcoma cell proliferation and metastasis. Saos-2 and U2OS cells were treated with mangiferin (25, 50, 75 and 100 µM) for 72 h. Mangiferin reduced the cell viability, invasion, and cell adhesion and migration rate. Matrix metalloproteinases-2/9 (MMP-2/9) mRNA expression was reduced significantly, while the levels of tissue inhibitors of metalloproteinases-1/2 (TIMP-1/2) were elevated in Saos-2 and U2OS cells. Mangiferin treatment significantly reduced parathyroid hormone receptor 1 (PTHR1) mRNA and protein expression by more than 0.5-fold in both osteosarcoma cells. In addition, the immunofluorescent analysis also showed decreased PTHR1 expression following treatment with mangiferin. In summary, we have demonstrated that treatment with mangiferin reduces cell viability, proliferation, invasion, adhesion and migration, and induces apoptosis of osteosarcoma cells. Therefore, treatment with mangiferin can be effective agent in inhibiting growth and inducing apoptosis in osteosarcoma cells. Our experimental results provide evidence for the therapeutic effect of mangiferin in osteosarcoma cells.