Molecular characterization of the anticancer properties associated with bee venom and its components in glioblastoma multiforme.

Glioblastoma multiforme (GBM) is a frequent form of malignant glioma. Strategic therapeutic approaches to treat this type of brain tumor currently involves a combination of surgery, radiotherapy and chemotherapy. Nevertheless, survival of GBM patients remains in the 12-15 months range following diagnosis. Development of novel therapeutic approaches for this malignancy is therefore of utmost importance. Interestingly, bee venom and its components have shown promising anti-cancer activities in various types of cancer even though information pertaining to GBMs have been limited. The current work was thus undertaken to better characterize the anti-cancer properties of bee venom and its components in Hs683, T98G and U373 human glioma cells. MTT-based cell viability assays revealed IC50 values of 7.12, 15.35 and 7.60 µg/mL for cell lines Hs683, T98G and U373 treated with bee venom, respectively. Furthermore, melittin treatment of these cell lines resulted in IC50 values of 7.77, 31.53 and 12.34 µg/mL, respectively. Cell viability assessment by flow cytometry analysis confirmed signs of late apoptosis and necrosis after only 1 h of treatment with either bee venom or melittin in all three cell lines. Immunoblotting-based quantification of apoptotic markers demonstrated increased expression of Bak and Bax, while Caspsase-3 levels were significantly lower when compared to control cells. Quantification by qRT-PCR showed increased expression levels of long non-coding RNAs RP11-838N2.4 and XIST in glioma cells treated with either bee venom or melittin. Overall, this study provides preliminary insight on molecular mechanisms via which bee venom and its main components can impact viability of glioma cells and warrants further investigation of its anticancer potential in gliomas.

Human scFv antibodies (Afribumabs) against Africanized bee venom: Advances in melittin recognition.

Africanized Apis mellifera bees, also known as killer bees, have an exceptional defensive instinct, characterized by mass attacks that may cause envenomation or death. From the years 2000-2013, 77,066 bee accidents occurred in Brazil. Bee venom comprises several substances, including melittin and phospholipase A2 (PLA2). Due to the lack of antivenom for bee envenomation, this study aimed to produce human monoclonal antibody fragments (single chain fragment variable; scFv), by using phage display technology. These fragments targeted melittin and PLA2, the two major components of bee venom, to minimize their toxic effects in cases of mass envenomation. Two phage antibody selections were performed using purified melittin. As the commercial melittin is contaminated with PLA2, phages specific to PLA2 were also obtained during one of the selections. Specific clones for melittin and PLA2 were selected for the production of soluble scFvs, named here Afribumabs: prefix: afrib- (from Africanized bee); stem/suffix: -umab (fully human antibody). Afribumabs 1 and 2 were tested in in vitro and in vivo assays to assess their ability to inhibit the toxic actions of purified melittin, PLA2, and crude bee venom. Afribumabs reduced hemolysis caused by purified melittin and PLA2 and by crude venom in vitro and reduced edema formation in the paws of mice and prolonged the survival of venom-injected animals in vivo. These results demonstrate that Afribumabs may contribute to the production of the first non-heterologous antivenom treatment against bee envenomation. Such a treatment may overcome some of the difficulties associated with conventional immunotherapy techniques.

[Effect of melittin on apoptosis and necrosis of U2 OS cells].

OBJECTIVE: To study the effect of melittin on apoptsis and necrosis of osteosarcoma cell line U2 OS in vitro. METHODS: 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. RESULTS: 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. CONCLUSION: Melittin inhibits the proliferation of osterosarcoma cell line through up-regulating Fas expression and inducing apoptsis.

[Comparison of anti-inflammatory, analgesic activities, anaphylactogenicity and acute toxicity between bee venom and its peptides].

Bee venom 1.0-2.0 mg/kg and bee venom peptides 1.0-2.0 mg/kg inhibited several inflammatory processes, such as ear swelling induced by xylene in mice, edema produced by injecting 1% carrageenin 0.1 ml beneath the plantar surface of hind paw in rats and showed a marked analgesic action induced by the hot plate and potassium antimony tartrate. Bee venom peptides had a markedly more effective action as compared with bee venom itself. The anaphylactogenicity of bee venom peptides was apparently milder than that of bee venom. The LD50 of bee venom ip in mice and bee venom peptides was 7.4 mg/kg and 7.9 mg/kg respectively.