Cytotoxin 1 from Naja atra Cantor venom induced necroptosis of leukemia cells.

BACKGROUND: Cytotoxin 1 (CTX1) purified from Naja atra Cantor venom could inhibit cancer cell proliferation, but the mechanism is not clear. This study aimed to investigate the mechanism by which leukemia cells are killed by CTX1. MATERIALS AND METHODS: HL-60 and KG1a cells were treated with CTX1 and the cell death was detected. RESULTS: The viability of HL-60 and KG1a cells decreased in a dose- and time-dependent manner after treatment with CTX1. CTX1 mainly induced late apoptosis and necrosis. The cell death induced by CTX1 could be rescued by specific necroptosis inhibitor Nec-1 but not by caspase inhibitor Z-VAD-fmk in HL-60 cells. In addition, CTX1 increased lysosome membrane permeability (LMP) and release of cathepsin B. CONCLUSION: CTX1 could induce necroptosis in leukemia cells, and it is related to LMP increase and cathepsin release. CTX1 could be a promising anti-cancer drug for leukemia therapy.

SVP-B5 peptide from Buthus martensii Karsch scorpion venom exerts hyperproliferative effects on irradiated hematopoietic cells.

Previous studies have demonstrated the radioprotective efficacy of scorpion venom peptide, fraction II (SVPII) from the venom of Buthus martensii Karsch. In the present study, the SVP-B5 polypeptide, which is one of the active components of SVPII, was purified using a two-step chromatographic process. SVP-B5 significantly promoted the proliferation of irradiated M-NFS-60 mouse-derived myelocytic leukemia cells. In addition, SVP-B5 effectively and persistently promoted hematopoietic recovery and expansion of hematopoietic cells after irradiation as demonstrated by cobblestone area forming cell and long-term bone marrow culture assays. Treatment of M-NFS-60 cells with SVP-B5 upregulated the expression of interleukin 3 receptor and activated the Janus kinase-2/signal transducer and activator of transcription 5 signaling pathway. In conclusion, the present study demonstrated that SVP-B5 has growth factor-like properties and may be used as a therapeutic modality in the recovery of severe myelosuppression, which is a common side effect of radiotherapy.

Effects of Scorpion venom peptide B5 on hematopoietic recovery in irradiated mice and the primary mechanisms.

Scorpion venom peptide B5 (SVP-B5) stimulates recovery of hematopoiesis after exposure to radiation. However, its radioprotective effects and mechanisms are still unclear. The aim of this study was to investigate the effects of SVP-B5 on hematopoietic recovery in mice after total body irradiation (TBI) at a dose of 7.5 Gy and 6 Gy and to explore the possible primary mechanisms. SVP-B5 at a dose of 2.63 µg/kg significantly reduced the mortality rate of mice after TBI (p < 0.05). It showed markedly protective effects against radiation injury. SVP-B5 also significantly increased the number of bone marrow nucleated cells (BMNCs) and increased the colony forming unit (CFU) number in irradiated mice, accelerated the post-irradiation recovery of peripheral blood leukocytes and platelets in mice. SVP-B5 treatment markedly reduced the Reactive Oxygen Species (ROS) levels in BMNCs after TBI, reduced γH2AX levels, and decreased the relative expression levels of p16 and p21 mRNA at day 14 (d14) after irradiation. Our study indicated that SVP-B5 could partially mitigate radiation-induced DNA damage, enhance the post-radiation hematopoietic recovery, and improve the survival rate probably through the ROS-p16/p21 pathway.

Scorpion venom peptide SPVII promotes irradiated cells proliferation and increases the expression of the IL-3 receptor.

BACKGROUND: The previous investigation demonstrated the radioprotective efficacy of peptides isolated from the venom of Buthus Martti Karsch. In this study, the effect of isolated scorpion venom peptide II (SVPII) on irradiated M-NFS-60 cells and mouse bone marrow mononuclear cells (BM-MNCs) was observed. The AlamarBlue cell viability assay, a colony-forming unit (CFU) assay, flow cytometry (FCM), immunofluorescence, and Western blotting were used to evaluate cell proliferation, cell cycle progression, and the expression of the IL-3 receptor (IL-3R) protein in non-irradiated and irradiated cells. RESULTS: Proliferation of irradiated M-NFS-60 cells was significantly accelerated by SPVII, and this effect was further enhanced by co-application of IL-3. Similarly, SPVII increased the number of BM-MNC CFUs and this proliferative effect was greater in the presence of SVPII plus IL-3. In addition, SPVII significantly altered cell cycle progression; SVPII enhanced the fraction of unirradiated M-NFS-60 cells in S phase and the fraction of irradiated M-NFS-60 cells arrested in G2/M. The expression of IL-3R protein by unirradiated M-NFS-60 cells was enhanced significantly by SVPII, and SVPII-induced IL-3R overexpression was 10-fold greater in irradiated M-NFS-60 cells. CONCLUSIONS: These results indicated the hematopoietic growth factor (HGF)-like effects of SVPII on irradiated cells, possibly mediated by upregulation of IL-3R.

The anticancer effect of cytotoxin 1 from Naja atra Cantor venom is mediated by a lysosomal cell death pathway involving lysosomal membrane permeabilization and cathepsin B release.

The cytotoxin family of cobra venom proteins, also called cardiotoxins, can activate both necrotic and apoptotic cell death pathways in cancer cells. Cytotoxin 1 (CTX1)from Naja atra Cantor venom is a 60 amino acid, 6698 Da protein with as yet untested anticancer efficacy and cell selectivity. We tested the toxicity of CTX1 on a number of cancer cell lines (MCF-7, P388, K562, and H22) and on one normal human cell line (16HBE). The rank order of cytotoxicity was MCF-7 > P388 ≈ K562 >H22 ≈ 16HBE, indicating that the effect of CTX1 on certain cancer cell types was relatively selective.Treatment with CTX1 greatly prolonged the survival of P388 ascites tumors bearing KM mice compared to cyclophosphamide treatment. Cell viability, apoptosis, and lysosomal permeability assays all demonstrated that CTX1 induced dose- and time-dependent cell death, with most cells exhibiting the morphological and biochemical features of late apoptosis and necrosis. Mitochondrial membrane potential was lost in CTX1-treated P388 cells. In addition, CTX1 induced an increase in both lysosomal membrane permeability and cathepsin B protease activity. These analyses reveal that CTX1 possesses significant and selective anticancer activity, likely by inducing programmed cell death through mitochondrial and/or lysosomal pathways.

[Induction of injury to endothelium of pulmonary artery due to entero superantigen by up regulation of lymphocyte chemokine receptor 5].

OBJECTIVE: To observe the injurious effect of T cell activated by Staphylococcus enterotoxin B (SEB) on human pulmonary artery endothelial cell (HPAEC) and explore its possible mechanism. METHODS: HPAEC was cocultured with SEB-activated T cells supernatant, and the secretion of chemotactic factors from HPAEC was examined. The Transwell inserts was used in chemoattraction assays. After HPAECs were cocultured with T cells and 10 ng/ml SEB for 3 days, HPAEC damage was monitored by microscopy and the terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) assay. RESULTS: Three kinds of tested chemokines showed a time dependent increase in all supernatant of HPAEC incubated with different concentrations of T cells. After 72 hours, the monocyte chemoattractant protein 1 (MCP 1, ng/ml) in 1×10(-2) , 1×10(-1), 1×10(0) T cell supernatant groups was 1.240±0.103, 4.200±0.305, 6.500±0.500, respectively, macrophage inflammatory protein 1α (MIP 1α, ng/ml) was 0.210±0.015, 0.287±0.012, 0.531±0.037, respectively , and Rantes (ng/ml) was 1.420±0.074, 7.634±0.630, 15.700±1.300, respectively. Rantes presented a two phase secretion mode: in early 6 hours it increased swiftly, but relatively slow at 12, 24, 48, 72 hours. T cell adherent to polycarbonate membrane increased after SEB stimulation in superantigen group compared with control group without SEB stimulation (86.38±14.50 vs. 16.50±2.50, P<0.01). When 10 ng/ml SEB-activated T cell was cocultured with HPAEC, more of originally suspended cultured T cells adhered to HPAEC monolayer [(15.50±1.08)% vs. (1.60±0.22)%, PP<0.01], whereas the cell adhesion ratio decreased markedly in 1 µg/ml Met Rantes group [(4.39±0.66)%, PP<0.01). FACs test of HPAEC adherent T cell showed lymphocyte chemokine receptor 5 (CCR5)/CD4 and CCR5/CD8 increased over 2.5 folds and 2.8 folds compared with 100 ng/ml SEB-activated T cell. Cell death rate of HPAEC was increased when cocultured with SEB-activated T cell in superantigen group compared with HPAEC normal incubation group [(32.50±4.50)% vs. (3.50±0.50)%, P<0.01]. CONCLUSION: Increased chemoattraction and adherence of SEB-activated T cells to HPAEC could damage HPAEC; this effect was possibly due to up regulation of CCR5 on T cell.

Effects of heating on the immunogenicity and biological toxicity of Deinagkistrodon acutus venom and its fractions.

To improve toxoid preparation, the effects of selective heat denaturation were assessed on Deinagkistrodon acutus venom. The venom and its fractions (peak 1 and peak 2 separated by gel filtration chromatography) were heated to various temperatures (45-70 degrees C) for 30 min, after which protein concentration, immunoreactivity, lethality, myotoxicity and hemorrhagic and membrane lysis activities of the samples were determined. In addition, the synergistic effects of the venom fractions were evaluated by separate or simultaneous intramuscular injection in mice. The results showed that the peak 1 fraction consisted primarily of proteins in the range of 18 to 105 kDa, while the peak 2 fraction consisted primarily of proteins smaller than 21 kDa. The hemorrhagic activity, immunoreactivity, and protein concentration of heated samples were gradually reduced as the temperature increased from 25 degrees C to 70 degrees C. Bioactivities significantly decreased but immunoreactivity was retained when the crude venom, peak 1 fraction, or peak 2 fraction were heated to the critical temperatures of 60 degrees C, 55 degrees C, or 60 degrees C, respectively. Synergistic effects of two kinds of heated fractions were observed in toxicity and antibody production after the peak 1 and peak 2 injected simultaneously or respectively. The results suggest that venom fractions heated and injected separately could significantly reduce their toxicity and enhance the neutralization of antiserum induced by them.

Preparation and characterization of immunoglobulin yolk against the venom of Naja naja atra.

Chinese Cobra (Naja naja atra) bite is one of the leading causes of snake-bite mortality in China. The traditional anti-cobra venom serum therapy was found to be expensive and with high frequency of side effects. Therefore attempts were made to generate a high titer immunoglobulin from egg yolk (IgY) of crude cobra-venom immunized Leghorn hens, and to standardize an effective method for producing avian antivenom in relatively pure form. The IgY was isolated first by water dilution method to remove the lipid, then extracted by ammonium sulfate precipitation, and purified through anion exchange chromatogram. The different purities of IgY from different isolating stages were submitted to enzyme-linked immunosorbent assay and SDS-PAGE to determine their titers. Immunoblotting showed that the purified IgY (ion exchange chromatography fraction, IECF) recognized several antigenic fractions of cobra venom, and presented with the character of polyclonal antibody. IECF on SDS-PAGE under reducing conditions migrated as a 65 kDa heavy chain and a 35 kDa light chain, respectively. The LD50 of the N. naja atra venom was 0.62 mg/kg body weight in mice. Four times the LD50 dose of venom was selected as challenge dose, and the ED50 of IgY was 3.04 mg IECF/mg venom. The results indicate that the activity of anti-snake venom IgY could be obviously elevated by ion exchange chromatography, thus possessing therapeutic significance for snakebite envenomation.

Scorpion venom peptides accelerate hematopoietic recovery of myelosuppression in irradiated mice.

Sublethally irradiated mice were administered with scorpion venom peptides (SVP) or with PBS in the saline control group, 3 days before and 7 consecutive days after irradiation. Hematopoietic recovery was assessed by bone marrow (BM) cell proliferation index (PI) and colony forming unit-granulocyte/macrophage (CFU-GM), spleen weight index (SI) and thymus weight index (TI), colony-forming unit-spleen (CFU-S) and peripheral leukocyte counts. In addition, IL-1alpha and SCF levels in BM, IL-6 and GM-CSF levels in serum were determined. In SVP treated groups, PI was improved dramatically versus control mice on day 22 after irradiation. The number of CFU-GM colonies in all SVP treated groups was higher than the control groups. The difference of the number of CFU-GM colonies between SVPV group (0.2 mg/kg) and the control was significant on day 5 and 10 after irradiation (p < 0.05). SVPIV (0.2 mg/kg) could activate the CFU-S formation on day 10 after irradiation. SI was in peak value on day 15 after irradiation in all groups and the SI value of SVPV treated group was higher than control group (p < 0.05). Our results suggest that SVP may be valuable natural peptides that relieve myelosuppression caused by radiation. The effect of SVP accelerating the hematopoietic recovery was potentially through a mechanism of stimulating the release of cytokines.

Scorpion venom polypeptide accelerate irradiated hematopoietic cells proliferation.

OBJECTIVE: To study the effects of Scorpion venom polypeptide (SVP) on the irradiated hematopoietic progenitor cells and the initial research of its mechanism. METHODS AND MATERIALS: (1) MTT array was used to select the effective concentration of SVP that had proliferate action on the irradiated early hematopoietic cells (K562), just like the doses of experiment in vitro; (2) The male BALB/c mice were divided into NS control group, SVP IV group and SVP V group. After treatment and sublethal irradiation, the C-KIT and IL-6Ralpha levels of bone marrow cells were detected by immunohistochemistry and tissue array; (3) The bone marrow cells of the normal BALB/c mice, given to SVP IV and SVP V after different action times respectively, were taken to extract the total proteins inside the cell, the phosphorylated STAT3 protein levels in JAK-STAT signal transduction pathway were detected by Western blot array. RESULTS: (1) 30mg/L SVP IV has an obvious effect to accelerate K562 cell proliferation; (2) The C-KIT and IL-6Ralpha expression on bone marrow cell surfaces in SVP IV and SVP V groups were negative (control with the saline group, p>0.05); (3) The phosphorylated STAT3 protein levels in bone marrow cells of SVP IV group had a rise-and-fall trend within 30min, while the test of SVP V group showed that the phosphorylated STAT3 protein levels obviously elevated after 30min. CONCLUSIONS: The results show that certain SVP IV concentration can protect the hematopoietic progenitor cells after irradiation, and the underlying mechanism of SVP accelerating the hematopoietic recovery in irradiated mice may be related to the activation of the JAK-STAT signal pathway.

Losartan prevents sepsis-induced acute lung injury and decreases activation of nuclear factor kappaB and mitogen-activated protein kinases.

Lack of specific and efficient therapy leads to the high mortality rate of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Losartan is a potent pharmaceutical drug for ALI/ARDS. However, the protective effects and mechanisms of losartan remain incompletely known. This study evaluates the effects of losartan on ALI/ARDS and further investigates the possible mechanisms of these protective effects. Mice received i.p. injections of the AT1 inhibitor losartan (15 mg/kg), or control vehicle, half hour after cecal ligation and puncture (CLP). Plasma TNF-alpha, IL-1beta, and IL-6 cytokines were assayed 6 h after CLP. Blood gas, wet/dry lung weight ratio, lung tissue histology for occurrence of ALI/ARDS, and survival were examined. Lastly, nuclear factor kappaB (NF-kappaB) activations, IkappaB-alpha degradations, phosphorylations of p38 MAPK, extracellular signal-regulated kinase 1/2, and c-Jun N-terminal kinase expressions were evaluated in lung tissue. Losartan treatment significantly attenuated TNF-alpha, IL-6, and IL-1beta 6 h after CLP. Furthermore, losartan prevented blood gas and histopathologic appearance of ALI/ARDS after sepsis and significantly improved survival. Finally, losartan given after sepsis led to inhibition of lung tissue NF-kappaB activation (P < 0.01 vs. CLP group), attenuated degradation of IkappaB-alpha, and inhibited phosphorylation of p38MAPK, extracellular signal-regulated kinase 1/2, and c-Jun N-terminal kinase, pathways critical for cytokine release. These data reveal that losartan exerts a protective effect on ALI/ARDS, and this protective effect may be dependent, at least in part, on NF-kappaB and MAPK mechanisms.

[Effect of fractions isolated from Naja naja atra venom on antioxidation in animals].

OBJECTIVE: To study the antioxidation of fraction F and H isolated from Naja naja atra venom on homogenate and RBC autoxidation. And to explore the effect of two fractions on the activities of antioxidation enzymes in mice. METHOD: Samples of tissues homogenates and RBC suspension were pretreated with fraction F/H, and then their generation of malondialdehyde(MDA) was examined. The effects of fraction F/H on O2-* produced by pyrogallol autoxidation and *OH produced by Cu2+ -VitC were checked. After being administrated i.p. with fraction F/H for 15 days, superoxide dismutase and hydroperoxidase in mice were measured for their activities. RESULT: Fraction F/H inhibited RBC autohemolysis and the generation of MDA decreased. The production of lipid peroxides in normal brain, liver and heart homogenate of rat and the elevation of lipid peroxides induced by cysteine and FeSO4 in homogenate were inhibited by addition of fraction F/H. The O2-* produced by autoxidation of pyrogallol and the *OH produced by Cu2+ -VitC system could be scavenged by fraction F/H (the potency of scavenging oxygen free radical is that fraction H > fraction F). Fraction F/H all increased the activities of several antioxidation enzymes in mice to different extents. CONCLUSION: Fraction F/H have the effect of antilipid peroxidation,may scavenge active oxygen free radical and increase the activity of SOD.