melitten and Osteosarcoma

Osteosarcoma is the most commonly seen type of primary malignant bone tumors in children and adolescents. Partial patients with osteosarcoma cannot tolerate the side effects of chemotherapy drugs. Hence, it is urgent to find anti-osteosarcoma drugs with low side effects. Melittin is an anti-tumor Traditional Chinese Medicine with low side effects. The purpose of this study was to explore the anti-osteosarcoma effect of melittin and its possible molecular mechanisms.. The effects of melittin on cell growth were detected by CCK-8, clonal formation, and flow cytometry. The related molecules were also investigated by Real-time PCR and Western blot. A xenograft model in nude mice was established to observe the effects of melittin on tumor growth and the related molecular expression was detected by immunohistochemistry.. Melittin can inhibit the proliferation of osteosarcoma 143B cells, reduce colony formation, and induce apoptosis while significantly up-regulating the expression of Bax and Caspase-3 and down-regulating the expression of Bcl-2 proteins. Moreover, treatment with melittin significantly reduced the mRNA and protein levels of β-catenin and Wnt/β- catenin related genes (LRP5, c-Myc, and Survivin) in osteosarcoma 143B cells in vitro. The xenograft model found that melittin significantly inhibited tumor growth and decreased the protein expression levels of β-catenin and Wnt/β- catenin related genes in vivo.. These findings show that melittin could inhibit the growth of osteosarcoma 143B cells, which may be related to the inhibition of Wnt/β-catenin signaling pathway activity and induce apoptosis by up-regulating the ratio of Bax/Bcl-2 in osteosarcoma 143B cells. Therefore, melittin is a promising anti-tumor drug for the treatment of osteosarcoma.

Topics: Adolescent; Animals; Antineoplastic Agents; Apoptosis; bcl-2-Associated X Protein; beta Catenin; Bone Neoplasms; Caspase 3; Cell Line, Tumor; Cell Proliferation; Child; Humans; Melitten; Mice; Mice, Nude; Osteosarcoma; Proto-Oncogene Proteins c-bcl-2; RNA, Messenger; Sincalide; Survivin; Wnt Signaling Pathway

Melittin is a major active peptide component of bee venom that has been demonstrated to show anti-tumor effects. Osteosarcoma is a type of bone tumor with a high degree of malignancy, and metastasis is the main challenge of osteosarcoma therapy. This study aimed to investigate the role of melittin in the lung metastasis of osteosarcoma. 143 B cells were treated with different concentrations of melittin in vitro. Wound-healing and transwell assays were performed to determine the cell migration and invasion potential. Quantitative real-time PCR and Western blot experiments were performed to evaluate the expression levels of Wnt/β-catenin signaling pathway-related factors after treatment with melittin. The orthotopic implantation model and hematoxylin-eosin staining were used to investigate the effect of melittin treatment on tumor formation and lung metastasis. Immunohistochemical staining and Western blot experiments were performed to indicate the melittin-mediated expression changes in Wnt/β-catenin signaling pathway-related factors. The cell migration and invasion potential were observed to be inhibited in a dose-dependent manner upon treatment with melittin. Treatment with medium and high concentrations of melittin attenuated the mRNA and protein expression of LRP5, β-catenin, MMP-2, cyclin D, c-Myc, survivin, MMP-9, and VEGF genes in vitro. Melittin significantly inhibited the growth of tibia xenografts in nude mice and decreased the number of lung metastatic nodules. Consistent with the results observed in vitro, treatment with melittin at medium and high concentrations attenuated the expression of Wnt/β-catenin signaling pathway-related factors in vivo. In vitro, Wnt/β-catenin signaling pathway was involved in Melittin-mediated -migration and invasion potential of 143 B cells. Similarly, as observed in the in vivo experiments, Wnt/β-catenin signaling pathway was also associated with the role of melittin on lung metastasis of osteosarcomas.

Topics: Animals; Bone Neoplasms; Cell Line, Tumor; Cell Movement; Cell Proliferation; Humans; Lung Neoplasms; Melitten; Mice; Mice, Nude; Osteosarcoma; Wnt Signaling Pathway

Endothelial progenitor cells (EPCs) are important in tumor angiogenesis. Stromal cell-derived factor-1α (SDF-1α) and its receptor C-X-C chemokine receptor type 4 (CXCR4) are key in stem cell homing. Melittin, a component of bee venom, exerts antitumor activity, however, the underlying mechanisms remain to be elucidated. The present study aimed to assess the effects of melittin on EPCs and angiogenesis in a mouse model of osteosarcoma. UMR‑106 cells and EPCs were treated with various concentrations of melittin and cell viability was determined using the MTT assay. EPC adherence, migration and tube forming ability were assessed. Furthermore, SDF‑1α, AKT and extracellular signal‑regulated kinase (ERK)1/2 expression levels were detected by western blotting. Nude mice were inoculated with UMR‑106 cells to establish an osteosarcoma mouse model. The tumors were injected with melittin, and its effects were assessed by immunohistochemistry and immunofluorescence. Melittin decreased the viability of UMR‑106 cells and EPCs. In addition, it decreased EPC adhesion, migration and tube formation when compared with control and SDF‑1α‑treated cells. Melittin decreased the expression of phosphorylated (p)‑AKT, p‑ERK1/2, SDF‑1α and CXCR4 in UMR‑106 cells and EPCs when compared with the control. The proportions of cluster of differentiation (CD)34/CD133 double‑positive cells were 16.4±10.4% in the control, and 7.0±4.4, 2.9±1.2 and 1.3±0.3% in tumors treated with 160, 320 and 640 µg/kg melittin per day, respectively (P<0.05). At 11 days, melittin reduced the tumor size when compared with that of the control (control, 4.8±1.3 cm3; melittin, 3.2±0.6, 2.6±0.5, and 2.0±0.2 cm3 for 160, 320 and 640 µg/kg, respectively; all P<0.05). Melittin decreased the microvessel density, and SDF‑1α and CXCR4 protein expression levels in the tumors. Melittin may decrease the effect of osteosarcoma on EPC‑mediated angiogenesis, possibly via inhibition of the SDF-1α/CXCR4 signaling pathway.

Topics: Animals; Biomarkers; Bone Neoplasms; Cell Adhesion; Cell Line, Tumor; Cell Movement; Cell Survival; Chemokine CXCL12; Disease Models, Animal; Endothelial Progenitor Cells; Extracellular Signal-Regulated MAP Kinases; Humans; Male; Melitten; Mice; Neovascularization, Pathologic; Osteosarcoma; Proto-Oncogene Proteins c-akt; Receptors, CXCR4; Signal Transduction; Tumor Burden; Xenograft Model Antitumor Assays

Melittin, a peptide from bee venom, is thought to be a phospholipase A(2) activator and Ca(2+) influx inducer that can evoke cell death in different cell types. However, the effect of melittin on cytosolic free Ca(2+) concentration ([Ca(2+)](i)) and viability has not been explored in human osteoblast-like cells. This study examined whether melittin altered [Ca(2+)](i) and killed cells in MG63 human osteosarcoma cells. [Ca(2+)](i) changes and cell viability were measured by using the fluorescent dyes fura-2 and WST-1, respectively. Melittin at concentrations above 0.075 microM increased [Ca(2+)](i) in a concentration-dependent manner. The Ca(2+) signal was abolished by removing extracellular Ca(2+). Melittin-induced Ca(2+) entry was confirmed by Mn(2+) quenching of fura-2 fluorescence at 360 nm excitation wavelength which was Ca(2+)-insensitive. The melittin-induced Ca(2+) influx was unchanged by modulation of protein kinase-C activity with phorbol 12-myristate 13-acetate (PMA) and GF 109203X, or inhibition of phospholipase A(2) with AACOCF(3) and aristolochic acid; but was substantially inhibited by blocking L-type Ca(2+) channels. At concentrations of 0.5 microM and 1 microM, melittin killed 33% and 45% of cells, respectively, via inducing apoptosis. Lower concentrations of melittin failed to kill cells. The cytotoxic effect of 1 microM melittin was completely reversed by pre-chelating cytosolic Ca(2+) with BAPTA. Taken together, these data showed that in MG63 cells, melittin induced a [Ca(2+)](i) increase by causing Ca(2+) entry through L-type Ca(2+) channels in a manner independent of protein kinase-C and phospholipase A(2) activity; and this [Ca(2+)](i) increase subsequently caused apoptosis.

Topics: Apoptosis; Calcium; Calcium Channels, L-Type; Cell Line, Tumor; Cell Survival; Egtazic Acid; Enzyme Inhibitors; Fluorescent Dyes; Fura-2; Humans; Indoles; Maleimides; Melitten; Osteoblasts; Osteosarcoma; Phospholipases A; Phospholipases A2; Tetradecanoylphorbol Acetate

To study the effect of melittin on apoptsis and necrosis of osteosarcoma cell line U2 OS in vitro.. Osteosarcoma cell line U2 OS was treated with melittin. The growth and proliferation was observed by MTT assay and cell counting, and the necrosis was estimated by Trypan blue staining. The cell apoptsis, Fas and Apo2. 7 expression were detected by cytometer.. The data showed that melittin could inhibit the proliferation of U2 OS dose-dependently at 16 and 64 mg/L. Cell apoptsis was detected by cytometer, when the cells were treated by 16 mg/L and 32 mg/L of melittin respectively, and the percentages of Fas and Apo2. 7 positive cells were increased.. Melittin inhibits the proliferation of osterosarcoma cell line through up-regulating Fas expression and inducing apoptsis.

Topics: Animals; Apoptosis; Cell Line, Tumor; Cell Proliferation; fas Receptor; Flow Cytometry; Inhibitory Concentration 50; Melitten; Osteonecrosis; Osteosarcoma; Proto-Oncogene Proteins; Receptors, Tumor Necrosis Factor