stilbenes and Osteosarcoma

This study investigated the effects and molecular mechanisms of ε-viniferin and α-viniferin in non-small cell lung cancer cell line A549, melanoma cell line A2058, and osteosarcoma cell lines HOS and U2OS. Results showed ε-viniferin having antiproliferative effects on HOS, U2OS, and A549 cells. Compared with ε-viniferin at the same concentration, α-viniferin had higher antiproliferative effects on HOS cells, but not the same effect on U2OS and A549 cells. Lower dose combination of α-viniferin and ε-viniferin had more synergistic effects on A549 cells than either drug alone. α-Viniferin induced apoptosis in HOS cells by decreasing expression of phospho-c-Jun-N-terminal kinase 1/2 (p-JNK1/2) and increasing expression of cleaved Poly (ADP-ribose) polymerase (PARP), whereas α-viniferin in combination with ε-viniferin induced apoptosis in A549 cells by decreasing expression of phospho-protein kinase B (p-AKT) and increasing expression of cleaved PARP and cleaved caspase-3. ε-Viniferin and α-viniferin have not been studied using in vivo tumor models for cancer. This research is the first showing that ε-viniferin treatment resulted in significant inhibition of tumor growth in A549-cell xenograft-bearing nude mice compared with the control group. Consequently, ε-viniferin and α-viniferin may prove to be new approaches and effective therapeutic agents for osteosarcoma and lung cancer treatment.

Topics: A549 Cells; Antineoplastic Agents; Apoptosis; Benzofurans; Carcinoma, Non-Small-Cell Lung; Humans; Lung Neoplasms; Necrosis; Osteosarcoma; Stilbenes

Numerous studies have shown that resveratrol can induce apoptosis in cancer cells. Trans-3, 5, 4'-trimethoxystilbene (TMS), a novel derivative of resveratrol, is a more potent anticancer compound than resveratrol and can induce apoptosis in cancer cells. Herein, we examined the mechanisms involved in TMS-mediated sensitization of human osteosarcoma (143B) cells to TNF-related apoptosis-inducing ligand- (TRAIL-) induced apoptosis. Our results showed that cotreatment with TSM and TRAIL activated caspases and increased PARP-1 cleavage in 143B cells. Decreasing cellular ROS levels using NAC reversed TSM- and TRAIL-induced apoptosis in 143B cells. NAC abolished the upregulated expression of PUMA and p53 induced by treatment with TRAIL and TSM. Silencing the expression of p53 or PUMA using RNA interference attenuated TSM-mediated sensitization of 143B cells to TRAIL-induced apoptosis. Knockdown of Bax also reversed TSM-induced sensitization of 143B cell to TRAIL-mediated apoptotic cell death. These results indicate that cotreatment with TRAIL and TSM evaluated intracellular ROS level, promoted DNA damage, and activated the Bax/PUMA/p53 pathway, leading to activation of both mitochondrial and caspase-mediated apoptosis in 143B cells. Orthotopic implantation of 143B cells in mice also demonstrated that cotreatment with TRAIL and TSM reversed resistance to apoptosis in cells without obvious adverse effects in normal cells.

Topics: Animals; Apoptosis; Apoptosis Regulatory Proteins; Caspases; Cell Line, Tumor; Female; Humans; Mice; Mice, Inbred BALB C; Mice, Nude; Osteosarcoma; Poly (ADP-Ribose) Polymerase-1; Proto-Oncogene Proteins; Reactive Oxygen Species; Resveratrol; Stilbenes; TNF-Related Apoptosis-Inducing Ligand; Tumor Suppressor Protein p53

Osteosarcoma is a bone cancer characterized by the production of osteoid tissue and immature bone from mesenchymal cells. Osteosarcoma mainly affects long bones (femur is most frequently site) and occur in children and young adults with greater incidence. Here, we investigated the role accomplished by polydatin, a natural antioxidative compound, in promoting osteogenic differentiation alone or after radiation therapy on osteosarcoma cells. In vitro, polydatin significantly induced cell cycle arrest in S-phase and enhanced bone alkaline phosphatase activity. Moreover, the differentiation process was paralleled by the activation of Wnt-

Topics: Cell Differentiation; Drugs, Chinese Herbal; Glucosides; Humans; Lipid Metabolism; Osteosarcoma; Stilbenes

This study aimed to investigate the effectiveness of anticancer therapy combining a cytotoxic chemotherapeutic agent, cisplatin (DDP), and a vascular disruptive drug, combretastatin A4 phosphate (CA4P), in osteosarcoma. First, a human osteosarcoma-xenografted mice model was established. Second, the transplanted tumor models were treated with DDP and CA4P in combination or as monotherapy. Third, the therapeutic effects and the mechanism of the drug combination in the inhibition of transplanted tumors was studied. Finally, the toxic effects of the drugs were observed and recorded. The results showed that DDP combined with CA4P significantly inhibited the growth and lung metastasis of transplanted tumors compared with the monotherapy drug group and vehicle control group. Histopathological analysis revealed that apoptotic and necrotic cell death significantly increased in the combination group, and combined treatment significantly inhibited the proliferation of osteosarcoma cells compared with either agent alone or the vehicle control. Additionally, no obvious toxic effects were observed in the combination group. These results indicate that the combined effects of DDP and CA4P on the progression of human osteosarcoma in vivo were superior to that of either agent alone. DDP combined with CA4P exerted synergistic effects at lower concentrations and promoted apoptosis and necrosis, as well as inhibited proliferation of osteosarcoma cells, but it did not increase the systemic toxic effects of chemotherapy. Our findings highlight CA4P as an effective anticancer agent candidate for combination with DDP in clinical applications to treat osteosarcoma.

Topics: Animals; Bone Neoplasms; Cell Line, Tumor; Cisplatin; Humans; Mice; Osteosarcoma; Stilbenes

Polydatin, a natural product, is detected in many daily diets, such as grape juices and peanut. Autophagy regulation is recognized as a new potential strategy for cancer therapy, and previous studies demonstrated that polydatin showed remarkable anti-cancer ability. Nevertheless, the capability of polydatin to induce autophagy and its role in anti-osteosarcoma remains obscure. In this study, we investigated the anticancer effect of polydatin on human osteosarcoma cell line MG-63 and its underlying mechanism. Our results indicated that polydatin significantly inhibited proliferation of MG-63 cells in a dose- and time-dependent manner, and increased their apoptosis and autophagic flux. Further experiments showed that polydatin reduced the expression and phosphorylation (Y705) level of STAT3 (Signal transducer and activator of transcription 3), increased the expression of autophagy-related genes (Atg12, Atg14, BECN1, PIC3K3), and therewith triggered autophagic cell death in MG-63 cells. Of note, the cytotoxicity effect of polydatin was rescued by co-treatment with Colivelin (STAT3 activator), suggesting the dependency of MG-63 cells on STAT3 for survival in this process. Moreover, polydatin-triggered autophagy and apoptosis were remarkably reduced following exposure to autophagy inhibitor 3-methyladenine, while cell viability was increased. In conclusion, these data demonstrated that polydatin induced MG-63 cell death through inducing apoptosis, and autophagy which was mediated via the STAT3 signaling. Therefore, polydatin might be a potential clinical drug in the remedy of osteosarcoma.

Topics: Antineoplastic Agents; Apoptosis; Autophagy; Bone Neoplasms; Cell Line, Tumor; Cell Proliferation; Cell Survival; Glucosides; Humans; Osteosarcoma; Phosphorylation; Signal Transduction; STAT3 Transcription Factor; Stilbenes

Piceatannol (Pice), a natural analog of resveratrol, has been identified as an anticancer agent in various cancers by modulating the expression of microRNAs (miRNAs/miRs). However, the molecular mechanisms underlying the anticancer effects of Pice in osteosarcoma (OS) cells remain unclear. Thus, we hypothesized that Pice exerts anticancer effects on OS cells via the regulation of miRNA expression. Herein, we performed a MTT assay and flow cytometric analysis to determine cell viability and apoptosis in OS cells treated with Pice, respectively. Our results showed that Pice inhibits proliferation in a dose‑dependent manner induces the apoptosis of OS cells. More importantly, miRNA microarray analysis identified that Pice alters miRNA expression profiles in human OS cells after treatment with Pice, and miR‑21 was the most significantly downregulated. In addition, the therapeutic effects of Pice on OS cells were weakened by restoration of miR‑21. In addition, we further verified that phosphatase and tensin homolog (PTEN), a tumor suppressor gene, is the functional target of miR‑21 and Pice blocks the PTEN/AKT signaling pathway through inhibiting miR‑21 expression in OS cells. Our findings suggested that Pice may exert anticancer effects on OS cells via mediating the miR‑21/PTEN/AKT signaling pathway and could be considered to be a potential anticancer agent for treating OS.

Topics: Brain Neoplasms; Cell Line, Tumor; Cell Proliferation; Cell Survival; Dose-Response Relationship, Drug; Gene Expression Regulation, Neoplastic; Humans; MicroRNAs; Osteosarcoma; Proto-Oncogene Proteins c-akt; PTEN Phosphohydrolase; Signal Transduction; Stilbenes

Oxyresveratrol (ORES) is a natural phenolic compound with multiple biological functions including antioxidation, anti‑inflammation and neuroprotection; however, the inhibitory effect of ORES on osteosarcoma remains largely unknown. The present study aimed to determine the effects of ORES on osteosarcoma cell Saos‑2. Cell Counting Kit‑8 assay was performed to detect Soas‑2 cell viability. Annexin‑FITC/PI staining and JC‑1 staining were used to measure cell apoptosis and the change of mitochondrial membrane potential. In addition, western blotting was conducted to determine the expression levels of apoptotic proteins and the phosphorylation of STAT3. It was found that ORES inhibited cell viability and induced apoptosis of osteosarcoma Saos‑2 cells in a concentration‑dependent manner. In addition, ORES increased the expression levels of apoptotic proteases caspase‑9 and caspase‑3 and reduced mitochondrial membrane potential. In response to ORES treatment, the expression levels of pro‑apoptotic proteins, Bad and Bax, were enhanced, whereas those of anti‑apoptotic proteins, Bcl‑2 and Bcl‑xL, were reduced. In addition, the phosphorylation of STAT3 was attenuated in Saos‑2 cells after treatment with ORES. Inhibition of cell viability and apoptosis induction by ORES were rescued by enhancement of STAT3 activation upon treatment with IL‑6. Collectively, the present study indicated that ORES induced apoptosis and inhibited cell viability, which may be associated with the inhibition of STAT3 activation; thus, ORES represents a promising agent for treating osteosarcoma.

Topics: Apoptosis; Caspase 3; Caspase 9; Cell Line, Tumor; Cell Proliferation; Cell Survival; Humans; Membrane Potential, Mitochondrial; Membrane Proteins; Mitochondria; Osteosarcoma; Plant Extracts; Proto-Oncogene Proteins c-bcl-2; Signal Transduction; STAT3 Transcription Factor; Stilbenes

Development of doxorubicin-resistance is the main difficulty for osteosarcoma treatment. LncRNA Taurine upregulated gene 1 (TUG1) has been identified as oncogenic lncRNA in different types of carcinomas and was involved in chemoresistance. We aim to evaluate the anti-proliferative effects and the underlying molecular mechanism of Polydatin in doxorubicin-resistant osteosarcoma.. Doxorubicin-resistant osteosarcoma cell lines were established. MTT, colony formation, apoptosis assay, qRT-PCR and Western blotting analysis, immunohistochemistry and animal study were carried out.. It has been showed Polydatin (50-250 μM) inhibited the cell proliferation in a dose- and time-dependent manner at 24 h, 48 h, and 72 h. Polydatin promoted the cell apoptosis significantly with the highest apoptosis rate >50%. Polydatin down-regulated TUG1 expression and TUG1/Akt signaling suppression was involved in Polydatin treated doxorubicin-resistant osteosarcoma cells. The in vivo study further confirmed the anti-cancer effect of Polydatin and related mechanisms.. Polydatin may be a novel therapeutic agent for doxorubicin-resistant osteosarcoma treatment and TUG1 would be a potential molecular target.

Topics: Animals; Antibiotics, Antineoplastic; Antineoplastic Agents, Phytogenic; Apoptosis; Bone Neoplasms; Cell Line, Tumor; Cell Proliferation; Dose-Response Relationship, Drug; Doxorubicin; Drug Resistance, Neoplasm; Gene Expression Regulation, Neoplastic; Glucosides; Humans; Male; Mice, Inbred BALB C; Mice, Nude; Osteosarcoma; Proto-Oncogene Proteins c-akt; RNA, Long Noncoding; Signal Transduction; Stilbenes; Time Factors; Tumor Burden; Xenograft Model Antitumor Assays

Despite improvements in the prognosis of osteosarcoma patients, chemotherapy fails in a considerable number of cases due to drug resistance. The development of novel agents may enhance chemosensitivity. This study explored the anticancer function of polydatin and its ability-in combination with paclitaxel-to overcome drug resistance in human osteosarcoma U-2OS and MG-63 cell lines. A cell proliferation assay (celll counting kit-8), a cell-cycle assay, an apoptosis assay (annexin V-fluorescein isothiocyanate/propidium iodide), and a cell migration assay (Transwell) were used to analyze cell activity. Western blot analysis and quantitative reverse-transcription polymerase chain reaction were performed to examine function-related mRNA and protein levels. Treatment with polydatin suppressed cell growth and migration in both cell lines. Moreover, polydatin induced cell apoptosis in both parental and paclitaxel-resistant cells, and cell-cycle arrest in the S phase. Furthermore, it altered the expression of various proteins associated with cell growth (Ki67, p21, cyclin A, cyclin E, and cyclin-dependent kinase 2), migration (matrix metalloproteinase-2 [MMP-2], MMP-9, and tissue inhibitor of metalloproteinase-1), apoptosis (poly[ADP-ribose] polymerase 1 and caspase 3), and drug resistance (p-glycoprotein 1, lung resistance-related protein 1, growth arrest and DNA damage-45α, glutathione S-transferase π, and heat shock protein 27) in paclitaxel-resistant osteosarcoma cells. Cells transfected with myr-Akt caused obvious upregulation and activation of Akt, which were significantly attenuated via polydatin treatment. In conclusion, polydatin may enhance the chemosensitivity of osteosarcoma cells to paclitaxel.

Topics: Apoptosis; Caspase 3; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Movement; Cell Proliferation; Drug Resistance, Neoplasm; Gene Expression Regulation, Neoplastic; Glucosides; Humans; Neoplasm Proteins; Osteosarcoma; Paclitaxel; Stilbenes

Combretastatin A-4 (CA-4), a tubulin-depolymerizing agent, shows promising antitumor efficacy and has been under several clinical trials in solid tumors for 10 years. Autophagy has an important pro-survival role in cancer therapy, thus targeting autophagy may improve the efficacy of antitumor agents. N-myc downstream-regulated gene 1 (NDRG1) is a significant stress regulatory gene, which mediates cell survival and chemoresistance. Here we reported that CA-4 could induce cell-protective autophagy, and combination treatment of CA-4 and autophagy inhibitor chloroquine (CQ) exerted synergistic cytotoxic effect on human osteosarcoma (OS) cells. Meanwhile, CA-4 or CQ could increase the expression of NDRG1 independently. We further performed mechanistic study to explore how CA-4 and CQ regulate the expression of NDRG1. Using luciferase reporter assay, we found that CA-4 transcriptionally upregulated NDRG1 expression, whereas CQ triggered colocalization of NDRG1 and lysosome, which subsequently prevented lysosome-dependent degradation of NDRG1. Further, we showed that knockdown of NDRG1 caused the defect of lysosomal function, which accumulated LC3-positive autophagosomes by decreasing their fusion with lysosomes. Moreover, NDRG1 inhibition increased apoptosis in response to combination treatment with CA-4 and CQ. Taken together, our study revealed abrogation of NDRG1 expression sensitizes OS cells to CA-4 by suppression of autophagosome-lysosome fusion. These results provide clues for developing more effective cancer therapeutic strategies by the concomitant treatment with CA-4 and clinical available autophagy inhibitors.

Topics: Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Autophagosomes; Autophagy; Cell Cycle Proteins; Cell Line, Tumor; Chloroquine; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques; Humans; Intracellular Signaling Peptides and Proteins; Lysosomes; Membrane Fusion; Models, Biological; Osteosarcoma; Stilbenes; Up-Regulation

An increase in tumor-associated macrophages (TAMs) around the tumor microenvironment has been closely associated with a poor prognosis in patients with cancer, and M2 TAMs promote tumor growth and tumor metastasis by stimulating angiogenesis or lymphangiogenesis in tumors. We herein examined the effects of nine synthetic hydroxystilbenes on M2 macrophage activation and differentiation, and three selected dihydroxystilbenes on vascular endothelial cell growth factor (VEGF)-C-induced tube formation in human lymphatic endothelial cells (HLECs) (in vitro). We also investigated the antitumor and antimetastatic effects of three synthetic dihydroxystilbenes in LM8-bearing mice in vivo. The three selected synthetic stilbenes (at concentrations of 5, 10, 25, and 50 μM) inhibited the production of interleukin-10 and monocyte chemoattractant protein-1 in M2 macrophages, but promoted that of transforming growth factor-β1. The three dihydroxystilbenes (at concentrations of 10-50 μM) inhibited the phosphorylation of signal transducer and activator of transcript 3 without affecting its expression in the differentiation of M2 macrophages. Furthermore, the 2,3- and 4,4'-dihydroxystilbene inhibited VEGF-C-induced lymphangiogenesis in HLECs. Both 2,3- and 4,4'-dihydroxystilbene (at 10 and 25 mg/kg, twice daily) inhibited tumor growth and metastasis to the lung in mice. These results suggested that the antitumor and antimetastatic effects of 2,3- and 4,4'-dihydroxystilbene were partly due to anti-lymphangiogenesis, and the regulation of M2 macrophage activation and differentiation.

Topics: Animals; Antineoplastic Agents; Bone Neoplasms; Cell Differentiation; Cell Line, Tumor; Chemokine CCL2; Dose-Response Relationship, Drug; Humans; Interleukin-10; Lung Neoplasms; Lymphangiogenesis; Lymphatic Vessels; Macrophage Activation; Macrophages; Male; Mice, Inbred C3H; Osteosarcoma; Phenotype; Phosphorylation; Signal Transduction; STAT3 Transcription Factor; Stilbenes; Transforming Growth Factor beta1; Tumor Microenvironment; Vascular Endothelial Growth Factor C; Xenograft Model Antitumor Assays

Resveratrol has been shown to have antineoplastic effects in vivo and in vitro. However, the effect of resveratrol on the hypoxia-enhanced proliferation and invasion of osteosarcoma cells remains unclear. In this study, we investigated the role of resveratrol on regulating proliferation and invasion of osteosarcoma cells under hypoxic conditions. Saos-2 cells were cultured under controlled hypoxic conditions (3% O2) or normoxic conditions. Resveratrol (50 µM) was added in the medium, and hypoxia inducible factor-1α (HIF-1α) siRNA was used to inhibit HIF-1α transcription. Proliferation of Saos-2 cells was evaluated by the methabenzthiazuron (MTT) assay. The invasive ability of Saos-2 cells was determined by a Transwell assay. HIF-1α, E-cadherin and vimentin protein levels were detected by western blot analysis. HIF-1α, E-cadherin and vimentin mRNA levels were assessed by RT-PCR. Compared to the control group, hypoxia significantly increased the proliferation rate and invasive ability of Saos-2 cells. Moreover, hypoxia markedly increased the E-cadherin level and decreased vimentin expression. However, resveratrol or HIF-1α silencing reverted all the above effects of hypoxia in Saos-2 cells. Moreover, resveratrol inhibited HIF-1α protein accumulation without affecting the HIF-1α mRNA level. These data suggest that resveratrol can inhibit the hypoxia‑enhanced proliferation, invasion and epithelial to mesenchymal transition process in osteosarcoma via downregulation of the HIF-1α protein. Thus, HIF-1α may be a promising drug target of resveratrol in the context of development of anticancer therapy for human osteosarcoma.

Topics: Antineoplastic Agents, Phytogenic; Cell Hypoxia; Cell Line, Tumor; Cell Movement; Cell Proliferation; Down-Regulation; Epithelial-Mesenchymal Transition; Gene Expression Regulation, Neoplastic; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Osteosarcoma; Resveratrol; Stilbenes

Osteosarcomas, the most common malignant bone tumors, show a potent capacity for local invasion and pulmonary metastasis. Resveratrol (RESV), a phytochemical, exhibits multiple tumor-suppressing activities and has been tested in clinical trials. However, the antitumor activities of RESV in osteosarcomas are not yet completely defined. In osteosarcoma cells, we found that RESV inhibited the migration/invasion in vitro and lung metastasis in vivo by suppressing matrix metalloproteinase (MMP)-2. We identified that RESV exhibited a transcriptional inhibitory effect on MMP-2 through reducing CREB-DNA-binding activity. Moreover, a microRNA (miR) analysis showed that miR-328 was predominantly upregulated after RESV treatment. Inhibition of miR-328 significantly relieved MMP-2 and motility suppression imposed by RESV treatment. Furthermore, ectopic miR-328 expression in highly invasive cells decreased MMP-2 expression and invasive abilities. Mechanistic investigations found that JNK and p38 MAPK signaling pathways were involved in RESV-regulated CREB-DNA-binding activity, miR328 expression, and cell motility. Clinical samples indicated inverse expression between MMP-2 and miR-328 in normal bone and osteosarcoma tissues. The inverse correlation of MMP-2 and miR-328 was also observed in tumor specimens, and MMP-2 expression was linked to tumor metastasis. Taken together, our results provide new insights into the role of RESV-induced molecular and epigenetic regulation in suppressing tumor metastasis.

Topics: 3' Untranslated Regions; Adult; Animals; Antineoplastic Agents; Binding Sites; Bone Neoplasms; Cell Line, Tumor; Cell Movement; CREB-Binding Protein; Dose-Response Relationship, Drug; Female; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Humans; JNK Mitogen-Activated Protein Kinases; Lung Neoplasms; Male; Matrix Metalloproteinase 2; Mice, SCID; MicroRNAs; Neoplasm Invasiveness; Osteosarcoma; p38 Mitogen-Activated Protein Kinases; Resveratrol; Signal Transduction; Stilbenes; Time Factors; Transcription, Genetic; Transfection; Xenograft Model Antitumor Assays; Young Adult

Doxorubicin (DOX) was first used in osteosarcoma in the early 1970s as a first-line antineoplastic drug. However, the occurrence of drug resistance in chemotherapeutic treatment has greatly restricted its use. When resistance to DOX treatment occurs, osteosarcoma may become not only resistant to the drug originally administered but also to a wide variety of structurally and mechanistically unrelated drugs. Thus, there is an urgent need to find ways of reversing DOX chemotherapy resistance in osteosarcoma. Plant-derived agents have great potential in preventing the onset of the carcinogenic process and enhancing the efficacy of conventional antitumor drugs. Alopecurone B (ALOB), a flavonoid, is isolated from Traditional Chinese Medicine Sophora alopecuroides L., and is reported to have potent inhibitory effect on multidrug resistance associated protein 1. In this study, a DOX-resistant osteosarcoma cell line (MG-63/DOX) was established by increasing the concentration gradient of DOX in a stepwise manner. MTT assay, flow cytometry analysis, dual-luciferase reporter gene assay, quantitative real-time polymerase chain reaction and Western blot analysis were applied to investigate the reversing effect of ALOB and its underlying mechanisms. The results indicated that ALOB mediated the resistance of MG-63/DOX cells to DOX by inhibiting P-glycoprotein function, transcription and expression. Besides, ALOB also enhanced the sensitivity of MG-63/DOX cells to other conventional chemotherapeutic drugs. Cell viability assay confirmed the reversing activity of ALOB. Furthermore, ALOB increased DOX-induced apoptosis at nontoxic concentration. In addition, ALOB showed inhibitory effect on NF-κB transcription in a DOX-independent manner. Furthermore, NF-κB signaling was suppressed by ALOB in an IKK-dependent manner. These studies not only demonstrate that ALOB is a potential agent for reversal of drug resistant cancers, but also testify that ALOB reverses multidrug resistance by inhibiting P-glycoprotein via NF-κB signaling.

Topics: Antineoplastic Agents; Apoptosis; ATP Binding Cassette Transporter, Subfamily B; Cell Line, Tumor; Doxorubicin; Drug Resistance, Neoplasm; Flavonoids; Humans; NF-kappa B; Osteosarcoma; Signal Transduction; Stilbenes

In the last 30 years, the 5-year-survival rate of patients with osteosarcoma has not improved as a result of the low prevalence and large tumor heterogeneity. Therefore, the development of novel drugs for the treatment of osteosarcoma is urgently required. The present study aimed to identify potential novel drugs for the treatment of osteosarcoma, thus used β‑catenin as a target and performed high content screening. In a total of 14 botanical extracts assessed, resveratrol markedly downregulated the expression of β‑catenin and significantly inhibited MG‑63 cell proliferation. CCK‑8 assay was used to confirm the anti‑osteosarcoma effect of resveratrol and flow cytometry and western blotting were performed to analyze the underlying mechanisms of the proapoptotic effects of resveratrol. β‑catenin is a vital member of the canonical Wnt signaling pathway and, therefore, the target genes of this pathway were further analyzed. The results of this analysis demonstrated that resveratrol suppressed the MG‑63 cells by inhibiting the canonical Wnt signaling pathway.

Topics: Antineoplastic Agents; Apoptosis; beta Catenin; Bone Neoplasms; Cell Line, Tumor; Cell Proliferation; Drug Screening Assays, Antitumor; Humans; Osteosarcoma; Resveratrol; Stilbenes; Wnt Signaling Pathway

Macrocyclic bisbibenzyls, characteristic components derived from liverworts, have various biological activities. Riccardin D (RD), a liverwort-derived naturally occurring macrocyclic bisbibenzyl, has been found to exert anticancer effects in multiple cancer cell types through apoptosis induction. However, the underlying mechanisms of such effects remain undefined. In addition, whether RD induces other forms of cell death such as autophagy is unknown. In this study, we found that the arrest of RD-caused U2OS (p53 wild) and Saos-2 (p53 null) cells in G1 phase was associated with the induction of p53 and p21(WAF1) in U2OS cells. RD-mediated cell cycle arrest was accompanied with apoptosis promotion as indicated by changes in nuclear morphology and expression of apoptosis-related proteins. Further studies revealed that the antiproliferation of RD was unaffected in the presence of p53 inhibitor but was partially reversed by a pan-inhibitor of caspases, suggesting that p53 was not required in RD-mediated apoptosis and that caspase-independent mechanisms were involved in RD-mediated cell death. Except for apoptosis, RD-induced autophagy occurred as evidenced by the accumulation of microtubule-associated protein-1 light chain-3B-II, formation of AVOs, punctate dots, and increased autophagic flux. Pharmacological blockade of autophagy activation markedly attenuated RD-mediated cell death. RD-induced cell death was significantly restored by the combination of autophagy and caspase inhibitors in osteosarcoma cells. Overall, our study revealed RD-induced caspase-dependent apoptosis and autophagy in cancer cells, as well as highlighted the importance of continued investigation on the use of RD as a potential anticancer candidate.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Autophagy; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cell Survival; Humans; Microtubule-Associated Proteins; Osteosarcoma; Phenyl Ethers; Stilbenes

Until recently, the supposed preventive effects of red wine against cardiovascular diseases, the so-called "French Paradox", has been associated to its antioxidant properties. The interest in the anticancer capacity of polyphenols present in red wine strongly increased consequently to the enormous number of studies on resveratrol. In this study, using lyophilized red wine, we present evidence that its anticancer effect in a cellular model is mediated by apoptotic and autophagic cell death. Using a human osteosarcoma cell line, U2Os, we found that the lyophilized red wine was cytotoxic in a dose-dependent manner with a maximum effect in the range of 100-200 μg/ml equivalents of gallic acid. A mixed phenotype of types I/II cell death was evidenced by means of specific assays following treatment of U2Os with lyophilized red wine, e.g., autophagy and apoptosis. We found that cell death induced by lyophilized red wine proceeded through a mechanism independent from its anti-oxidant activity and involving the inhibition of PI3K/Akt kinase signaling. Considering the relative low concentration of each single bioactive compound in lyophilized red wine, our study suggests the activation of synergistic mechanism able to inhibit growth in malignant cells.

Topics: Alcohols; Antioxidants; Apoptosis; Autophagy; Cell Line, Tumor; Cell Proliferation; Cell Survival; Freeze Drying; Humans; Osteosarcoma; Polyphenols; Proto-Oncogene Proteins c-akt; Reactive Oxygen Species; Resveratrol; Signal Transduction; Stilbenes; Wine

Osteosarcoma is a high-grade malignant bone tumor. Pterostilbene (PTE) is a natural, dimethylated analog of resveratrol with higher bioavailability. While PTE has been shown to have potent antitumor activity against various types of cancer, the molecular mechanisms underlying the effects of PTE remain largely unknown. The Janus kinase 2/Signal Transducer and Activator of Transcription 3 (JAK2/STAT3) signaling pathway plays a crucial role in tumorigenesis and immune development. In this study, we assessed the antitumor activity of PTE against human osteosarcoma cells and explored the role of JAK2/STAT3 and apoptosis-related signaling pathways on the activity of PTE. PTE treatment resulted in a dose- and time-dependent inhibition of osteosarcoma cell viability. Additionally, PTE exhibited strong antitumor activity, as evidenced not only by reductions in tumor cell adhesion, migration and mitochondrial membrane potential (MMP) but also by increases in the apoptotic index, reactive oxygen species (ROS) and several biochemical parameters. Furthermore, PTE treatment directly inhibited the phosphorylation of JAK2 at Tyr 1007 and the downstream activation of STAT3. PTE also down-regulated the expression of STAT3 target genes, including the anti-apoptotic proteins Bcl-xL and Mcl-1, leading to the up-regulation of mitochondrial apoptosis pathway-related proteins (Bax, Bak, cytosolic Cytochrome c, and cleaved Caspase3) and cyclin-dependent kinase inhibitors such as p21 and p27. PTE, used in combination with a known JAK2/STAT3 inhibitor, AG490, further decreased the viability of osteosarcoma cells. Taken together, PTE is a potent inhibitor of osteosarcoma cell growth that targets the JAK2/STAT3 signaling pathway. These data suggest that inhibition of JAK2/STAT3 signaling is a novel mechanism of action for PTE during therapeutic intervention in osteosarcoma cancers.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Cell Adhesion; Cell Line, Tumor; Cell Movement; Cell Survival; Dose-Response Relationship, Drug; Down-Regulation; Gene Expression Regulation, Neoplastic; Humans; Janus Kinase 2; Membrane Potential, Mitochondrial; Mitochondria; Osteosarcoma; Reactive Oxygen Species; Signal Transduction; STAT3 Transcription Factor; Stilbenes; Time Factors; Tyrphostins; Up-Regulation

Dihydroptychantol A (DHA), a novel macrocyclic bisbibenzyl compound extracted from liverwort Asterella angusta, has antifungal and multi-drug resistance reversal properties. Here, the chemically synthesized DHA was employed to test its anti-cancer activities in human osteosarcoma U2OS cells. Our results demonstrated that DHA induced autophagy followed by apoptotic cell death accompanied with G₂/M-phase cell cycle arrest in U2OS cells. DHA-induced autophagy was morphologically characterized by the formation of double membrane-bound autophagic vacuoles recognizable at the ultrastructural level. DHA also increased the levels of LC3-II, a marker of autophagy. Surprisingly, DHA-mediated apoptotic cell death was potentiated by the autophagy inhibitor 3-methyladenine, suggesting that autophagy may play a protective role that impedes the eventual cell death. Furthermore, p53 was shown to be involved in DHA-mediated autophagy and apoptosis. In this connection, DHA increased nuclear expression of p53, induced p53 phosphorylation, and upregulated p53 target gene p21(Waf1/Cip1). In contrast, cytoplasmic p53 was reduced by DHA, which contributed to the stimulation of autophagy. In relation to the cell cycle, DHA decreased the expression of cyclin B₁, a cyclin required for progression through the G₂/M phase. Taken together, DHA induces G₂/M-phase cell cycle arrest and apoptosis in U2OS cells. DHA-induced apoptosis was preceded by the induction of protective autophagy. DHA-mediated autophagy and apoptosis are associated with the cytoplasmic and nuclear functions of p53.

Topics: Apoptosis; Autophagy; Bibenzyls; Cell Line, Tumor; Humans; Macrocyclic Compounds; Osteosarcoma; Phenyl Ethers; Signal Transduction; Stilbenes; Tumor Suppressor Protein p53

Vascular-targeting agents (VTAs) can be divided into two groups: anti-angiogenesis agents and vascular disrupting agents (VDAs). The purpose of this study was to evaluate the antineoplastic activity of a combination of the anti-angiogenesis agent, Endostar, and the VDA combretastatin, A4 phosphate (CA4P). This study is the first to evaluate the activity of this combination against tumors and the first to investigate the activity of the combination against osteosarcoma. Endostar combined with CA4P had a good anti-tumor effect with no significant toxicity, and was at least not inferior to adriamycin, which is the main drug for osteosarcoma. The use of VDAs combined with anti-angiogenic drugs can result in significantly enhanced anti-tumor effects, providing a novel approach to cancer treatment, which could effectively complement standard treatments. It is believed that this exciting new treatment has the potential to transform the management of cancer.

Topics: Animals; Antineoplastic Agents, Phytogenic; Antineoplastic Combined Chemotherapy Protocols; Bone Neoplasms; Cell Line, Tumor; Drug Synergism; Endostatins; Female; Humans; Mice; Mice, Inbred BALB C; Mice, Nude; Osteosarcoma; Random Allocation; Recombinant Proteins; Stilbenes; Xenograft Model Antitumor Assays

The phytoalexin resveratrol has been described to have chemopreventive and chemotherapeutic effects in several tumor models while its effects on osteosarcoma have not been extensively studied. Additionally, resveratrol is a potent activator of the Sirt1/Sir2 (silent information regulator 2) family of NAD-dependent deacetylases which plays a role in calorie restriction-mediated tumor suppression. In the present study, we evaluated the effect of resveratrol on growth and apoptosis in four osteosarcoma cell lines (HOS, Saos-2, U-2 OS and MG-63) and a normal human osteoblast cell line (NHOst). We found that Sirt1 protein was relatively higher expressed in the tumor cells than normal osteoblasts. Consistently, resveratrol induced apoptosis in a dose-dependent fashion in the osteosarcoma cells but had minor effect on normal osteoblasts. Also, a similar effect could be elicited by another Sirt1 activator, isonicotinamide. In addition, the pro-apoptotic effect of resveratrol could be enhanced by nutrition restriction elicited by l-asparaginase. We postulate that these effects by resveratrol are mediated via Sirt1 but further studies are needed to confirm or refute this theory.

Topics: Anticarcinogenic Agents; Apoptosis; Cell Line, Tumor; Cell Proliferation; Dose-Response Relationship, Drug; Growth Inhibitors; Humans; Niacinamide; Osteosarcoma; Resveratrol; Sirtuin 1; Sirtuins; Stilbenes

The chemopreventive activity of resveratrol (RSVL) has been demonstrated in several types of cancer. However, its effects and the underling mechanisms remain poorly understood. In this study, we investigated the involvement of the mitogen activated protein kinase (MAPK)/p53 signal transduction mechanism in RSVL-induced growth inhibition using a human osteosarcoma cell line. We demonstrate that RSVL reduces cell viability and growth of SJSA1 osteosarcoma cells. Morphological profiles and 4,6-diamidino-2-phenylindole nuclear staining of RSVL-treated cells indicated marked nuclear fragmentation. Cleavage of the (116-kDa) poly(ADP-ribose) polymerase protein into an 89-kDa fragment (a proapoptotic marker system) was substantially augmented by RSVL treatment. RSVL-dependent growth impairment was preceded by enhanced phosphorylation of extracellular signal-regulated kinase (ERK)1/2 (at Thr202/Tyr204). Likewise, RSVL increased the phosphorylation of p53 tumor suppressor protein (at Ser15). The effects of RSVL on ERKs and on p53 phosphorylation were abrogated by either the MAPK inhibitor PD98059 or the p53 inhibitor pifithrine-alpha. The present study indicates that RSVL antiproliferative effects on osteosarcoma cells are mediated by the activation of the ERKs/p53 signaling pathway and therefore identifies new targets for strategies to treat and/or prevent osteosarcoma.

Topics: Blotting, Western; Bone Neoplasms; Cell Line, Tumor; Cell Proliferation; Dose-Response Relationship, Drug; Extracellular Signal-Regulated MAP Kinases; Humans; Osteosarcoma; Poly(ADP-ribose) Polymerases; Resveratrol; Stilbenes; Tumor Suppressor Protein p53

Recent evidence suggests that inflammatory cytokines and growth factors contribute to arsenite (As)-induced human carcinogenesis. We investigated the expression of inflammatory cytokine mRNAs during the transformation process induced by chronic As exposure in non-tumorigenic human osteogenic sarcoma (N-HOS) cells using gene arrays, and results were confirmed by RT-PCR and protein arrays. Caffeic acid phenethyl ester (CAPE), a naturally occurring immunomodulating agent, was used to evaluate the role of inflammatory factors in the process of As-mediated N-HOS cell transformation and in As-transformed HOS (AsT-HOS) cells. We found that an 8-week continuous exposure of N-HOS to 0.3 microM arsenite resulted in HOS cell transformation. That exposure also caused substantial decreases in inflammatory cytokine mRNAs, such as interleukin (IL) IL-1alpha, IL-2, IL-8, IL-18, MCP-1, TGF-beta2, and TNF-alpha, while it increased c-jun mRNA in a time-dependent manner. Co-incubation of N-HOS with As and CAPE (0.5-2.5 microM) prevented As-mediated declines in cytokine mRNAs in the co-treated cells, as well as their transformation to anchorage independence, while it caused decreases in c-jun mRNA. CAPE (up to 10 microM) had no effect on growth of N-HOS cells. However, CAPE (1-10 microM) treatment of AsT-HOS cells inhibited cell growth, induced cell cycle G2/M arrest, and triggered apoptosis, accompanied by changes in cytokine gene expression, as well as decreases in cyclin B1 and cdc2 abundance. Resveratrol (RV) and (-)(.) epigallocatechin gallate (EGCG), preventive agents present in grapes and green tea, respectively, induced similar changes in AsT-HOS cell growth but required much higher doses than CAPE to cause 50% growth arrest (<2.5 microM CAPE versus 25 microM RV or 50 microM EGCG). Overall, our findings suggest that inflammatory cytokines play an important role in the suppressive effects of CAPE on As-induced cell transformation and in the selective cytotoxicity of CAPE to As-transformed HOS cells.

Topics: Antioxidants; Apoptosis; Arsenites; Caffeic Acids; Catechin; Cell Growth Processes; Cell Line; Cell Survival; Cell Transformation, Neoplastic; Cytokines; Drug Interactions; Flow Cytometry; Humans; Oligonucleotide Array Sequence Analysis; Osteosarcoma; Phenylethyl Alcohol; Resveratrol; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Stilbenes