Targeted delivery of antitumoral therapy to glioma and other malignancies with synthetic chlorotoxin (TM-601)

Targeted therapies for cancer is a rapidly advancing field, but the identification of tumor-specific ligands has proven difficult. Chlorotoxin (CTX) is a small, 36 amino acid neurotoxin isolated from the venom of the Giant Yellow Israeli scorpion Leiurus Quinquestriatus. Interestingly, the peptide has been found to preferentially bind to a variety of human malignancies, but shows little or no binding to normal human tissues. A synthetic version of this peptide (TM-601) has been manufactured and covalently linked to iodine 131 (131I-TM-601) as a means of targeting radiation to tumor cells. Preclinical studies and Phase I clinical trials have been completed in patients with recurrent glioma, a type of malignant brain tumor. These studies demonstrated that intracavitary dosing of 131I-TM-601 appears safe, minimally toxic, and binds malignant glioma with high affinity and for long durations. A Phase II trial of this agent using higher doses of radioactivity and repeated local administrations is underway. In addition, enrolment has begun in a Phase I trial evaluating whether systemically delivered 131I-TM-601 can be used to image metastatic solid tumors and primary gliomas. Due to its small size, selective tumor binding properties, minimal toxicity and relative ease of manipulation, CTX represents a potentially important targeting agent for many cancers.

Analgesic Effects of GpTx-1, PF-04856264 and CNV1014802 in a Mouse Model of NaV1.7-Mediated Pain

Loss-of-function mutations of Na(V)1.7 lead to congenital insensitivity to pain, a rare condition resulting in individuals who are otherwise normal except for the inability to sense pain, making pharmacological inhibition of Na(V)1.7 a promising therapeutic strategy for the treatment of pain. We characterized a novel mouse model of Na(V)1.7-mediated pain based on intraplantar injection of the scorpion toxin OD1, which is suitable for rapid in vivo profiling of Na(V)1.7 inhibitors. Intraplantar injection of OD1 caused spontaneous pain behaviors, which were reversed by co-injection with Na(V)1.7 inhibitors and significantly reduced in Na(V)1.7(-/-) mice. To validate the use of the model for profiling Na(V)1.7 inhibitors, we determined the Na(V) selectivity and tested the efficacy of the reported Na(V)1.7 inhibitors GpTx-1, PF-04856264 and CNV1014802 (raxatrigine). GpTx-1 selectively inhibited Na(V)1.7 and was effective when co-administered with OD1, but lacked efficacy when delivered systemically. PF-04856264 state-dependently and selectively inhibited Na(V)1.7 and significantly reduced OD1-induced spontaneous pain when delivered locally and systemically. CNV1014802 state-dependently, but non-selectively, inhibited Na(V) channels and was only effective in the OD1 model when delivered systemically. Our novel model of Na(V)1.7-mediated pain based on intraplantar injection of OD1 is thus suitable for the rapid in vivo characterization of the analgesic efficacy of Na(V)1.7 inhibitors.

A Combined Approach Employing Chlorotoxin-Nanovectors and Low Dose Radiation To Reach Infiltrating Tumor Niches in Glioblastoma

Glioblastoma multiforme (GBM) is the most aggressive form of glioma, with life expectancy of around 2 years after diagnosis, due to recidivism and to the blood-brain barrier (BBB) limiting the amount of drugs which reach the residual malignant cells, thus contributing to the failure of chemotherapies. To bypass the obstacles imposed by the BBB, we investigated the use of nanotechnologies combined with radiotherapy, as a potential therapeutic strategy for GBM. We used poly(lactic-co-glycolic acid) (PLGA) nanoparticles (PNP) conjugated to chlorotoxin (CTX), a peptide reported to bind selectively to glioma cells. Silver nanoparticles were entrapped inside the functionalized nanoparticles (Ag-PNP-CTX), to allow detection and quantification of the cellular uptake by confocal microscopy, both in vitro and in vivo. In vitro experiments performed with different human glioblastoma cell lines showed higher cytoplasmic uptake of Ag-PNP-CTX, with respect to nonfunctionalized nanoparticles. In vivo experiments showed that Ag-NP-CTX efficiently targets the tumor, but are scarcely effective in crossing the blood brain barrier in the healthy brain, where dispersed metastatic cells are present. We show here that single whole brain X-ray irradiation, performed 20 h before nanoparticle injection, enhances the expression of the CTX targets, MMP-2 and ClC-3, and, through BBB permeabilization, potently increases the amount of internalized Ag-PNP-CTX even in dispersed cells, and generated an efficient antitumor synergistic effect able to inhibit in vivo tumor growth. Notably, the application of Ag-PNP-CTX to irradiated tumor cells decreases the extracellular activity of MMP-2. By targeting dispersed GBM cells and reducing MMP-2 activity, the combined use of CTX-nanovectors with radiotherapy may represent a promising therapeutic approach toward GBM.

Purification and N-terminal partial sequence of anti-epilepsy peptide from venom of the scorpion Buthus martensii Karsch

An anti-epilepsy peptide (AEP) was isolated and purified from venom of the scorpion Buthus martensii Karsch. The purification procedure included CM-Sephadex C-50 chromatography, gel filtration on Sephadex G-50 and DEAE-Sephadex A-50 chromatography. Its homogeneity was demonstrated by pH 4.3 polyacrylamide-disc-gel electrophoresis, focusing electrophoresis and SDS/polyacrylamide-disc-gel electrophoresis. The Mr of this peptide, calculated from measurements in SDS/15%-polyacrylamide-disc-gel and SDS/20%-polyacrylamide-disc-gel electrophoresis, is 8300. The isoelectric point is 8.52 by pH 8-9.5-range isoelectric focusing. No haemorrhagic or toxic activities were found. No toxicity was found even after the dose reached 28 mg/kg. The pharmacological tests showed that the AEP had no effect on heart rate, blood pressure or electrocardiogram, but strongly inhibited epilepsy induced by coriaria lactone and cephaloridine. The fluorescence spectrum showed that the peptide has a strong emission peak at 337 nm. Amino acid analysis suggested that the AEP is composed of 66 residues from 18 amino acids and has an Mr of 8290. The sequence of the first 50 N-terminal residues is as follows: Asp-Gly-Tyr-Ile-Arg-Gly-Ser-Asp-Asn-Cys-Lys-Val-Ser-Cys-Leu-Leu-Gly-Asn- Glu-Gly - Cys-Asn-Lys-Glu-Cys-Arg-Ala-Tyr-Gly-Ala-Ser-Tyr-Gly-Tyr-Cys-Trp-Thr-Val- Lys-Leu - Ala-Gln-Asp-Cys-Glu-Gly-Leu-Pro-Asp-Thr-.

Radiation dosimetry of 131I-chlorotoxin for targeted radiotherapy in glioma-bearing mice

Chlorotoxin, or TM-601, is a peptide derived from the venom of the scorpionLeiurus Quinquestriatus that specifically binds to malignant brain tumors, but not to normal tissues. Targeted radiotherapy using 131I-Chlorotoxin is promising for post-surgery treatment of brain tumors. This study reports dosimetry results of 131I-Chlorotoxin in athymic nude mice with intracranially implanted human glioma xenografts and projected radiation doses in patients receiving 370 MBq of 131I-Chlorotoxin. 125I/131I-Chlorotoxin were injected into the right brain where D54 MG xenografts were implanted. Mice were sacrificed 24-96 h later. The blood, normal organs, and tumors were weighed and counted to determine 131I-Chlorotoxin concentration. The radiation dose from 131I was calculated based on non-penetrating radiation in the mouse model. Assuming similar tissue uptake in mice and patients, radiation doses for patients were extrapolated. Distributions of 125I/131I-Chlorotoxin were only significant in tumor, stomach, kidneys, and brain (injection site), reflecting non-specific uptake of Chlorotoxin in normal tissues. Mean radiation dose (cGy/37 kBq) was 58.2 for tumor, 17.9 for brains, 1.8 for marrow, 27.1 for stomach, 16.0 for kidneys in mice. For intracranial injection of 370 MBq 131I-Chlorotoxin in patients, extrapolated patient dose (cGy) was 70 for brains, 6 for marrow, 35 for stomach, 60 to kidneys, 227 to tumor, suggesting that 3.7 GBq of 131I-Chlorotoxin can be safely administrated to patients. These promising results demonstrated potential in improving patient survival using this novel targeting agent.

Chlorotoxin-A Multimodal Imaging Platform for Targeting Glioma Tumors

Chlorotoxin (CTX) is a 36-amino-acid disulfide-containing peptide derived from the venom of the scorpion Leiurus quinquestriatus. CTX alters physiology in numerous ways. It interacts with voltage gated chloride channels, Annexin-2, and matrix metalloproteinase-2 (MMP-2). CTX-based bioconjugates have been widely subjected to phase I/II clinical trials and have shown substantial promise. Many studies have demonstrated that CTX preferentially binds to neuroectodermal tumors, such as glioblastoma, without cross-reactivity to normal brain cells. With its ability to penetrate the blood-brain-barrier (BBB) and its tyrosine residue allows covalent conjugation with functional moieties, CTX is an attractive platform to explore development of diagnostic and therapeutic agents for gliomas. In this review, we outline CTX structure and its molecular targets, summarize molecular variations of CTX developed for glioma imaging, and discuss future trends and perspectives for CTX conjugates as a theranostic agent.

StCT2, a new antibacterial peptide characterized from the venom of the scorpion Scorpiops tibetanus

Bacterial infection poses an increasing threat to global public health and new types of antibacterial agents are urgently needed to respond to the threat. Scorpion venom contains series of bioactive peptides, among which antibacterial peptide is an important part. Herein, a new antimicrobial peptide StCT2 was characterized from the venomous gland cDNA library of the Scorpiops tibetanus. The full-length cDNA of StCT2 is 369 nucleotides encoding the precursor that contains a putative 24 residues signal peptide, a presumed 14 residues mature peptide, and a putative 37 residues acidic propeptide at the C-terminus. The minimal inhibition concentrations (MICs) of StCT2 for Staphylococcus aureus were 6.25-25μg/ml, including antibiotic-resistant strains such as methicillin resistant S. aureus (MRSA). StCT2 was further found to show high in vivo antimicrobial activity by an S. aureus infection mouse model. StCT2 exerted its antimicrobial activity via a rapid bactericidal mechanism. Taken together, these results demonstrate the efficacy and general mechanism of StCT2 antimicrobial action and the therapeutic potential of StCT2 as a new antimicrobial peptide.

Toxins in anti-nociception and anti-inflammation

The use of toxins as novel molecular probes to study the structure-function relationship of ion-channels and receptors as well as potential therapeutics in the treatment of wide variety of diseases is well documented. The high specificity and selectivity of these toxins have attracted a great deal of interest as candidates for drug development. This review highlights the involvement of the proteins and peptide toxins as well as non-proteinaceous compounds derived from both venomous and non-venomous animals, in anti-nociception and anti-inflammation. The possible mechanisms of these potential therapeutic agents and possible clinical applications in the treatment of pain and inflammation are also summarized.

Purification, characterization, and bioactivity of a new analgesic-antitumor peptide from Chinese scorpion Buthus martensii Karsch

Scorpion venoms are complex mixtures of dozens or even hundreds of distinct proteins, many of which have diverse bioactivities. In this study, after bioassay-driven chromatographic purification, a new dual-function peptide with analgesic and antitumor activities was isolated and designated BmK AGAP-SYPU2. The first 12 amino acid residues were sequenced with Edman degradation. The cDNA was cloned by using rapid amplification of cDNA ends from the cDNA pool from scorpion glands. The amino acid sequence of BmK AGAP-SYPU2 was then deduced, and is consistent with the molecular mass measured with MALDI-TOF-MS. A preliminary pharmacological analysis revealed the following: in the dose-effect curve plotted with the mouse-twisting test, BmK AGAP-SYPU2 showed analgesic activity with an ED50 value of 1.42 mg/kg; in the time-effect curves plotted with a hot-plate procedure, BmK AGAP-SYPU2 had similar effects to those of the painkiller morphine, except for its longer duration. BmK AGAP-SYPU2 also showed antitumor activity against Ehrlich ascites tumor and S-180 fibrosarcoma models in vivo. Sequence alignment and homology modeling showed that BmK AGAP-SYPU2 is highly conserved relative to other scorpion α-toxins. However, a few different amino acids endow it with unique molecular properties, which may be responsible for its specific bioactivities. BmK AGAP-SYPU2, a new scorpion neurotoxin with dual functions, is a potential candidate drug amenable to exploitation and modification.

Inhibition effects of scorpion venom extracts (Buthus matensii Karsch) on the growth of human breast cancer MCF-7 cells

BACKGROUND

To observe the inhibition effects of the Buthus matensii Karsch (BmK) scorpion venom extracts on the growth of human breast cancer MCF-7 cells, and to explore its mechanisms.

METHODS

Two common tumor cells (SMMC7721, MCF-7) were examined for the one which wasmore sensitivity to scorpion venom by MTT method. Cell cycle was determined by flow cytometry. Immunocytochemistry was applied to detect apoptosis-related protein Caspase-3 and Bcl-2 levels, while the expression of cell cycle-related protein Cyclin D1 was shown by Western blotting.

RESULTS

Our data indicated that MCF-7 was the more sensitive cell line to scorpion venom. The extracts of scorpion venom could inhibit the growth and proliferation of MCF-7 cells. Furthermore, the extract of scorpion venom induced apoptosis through Caspase-3 up-regulation while Bcl-2 down-regulation in MCF-7 cells. In addition, the extracts of scorpion venom blocked the cells from G0/G1 phase to S phase and decreased cell cycle-related protein Cyclin D1 level after drug intervention compared with the negative control group.

CONCLUSIONS

These results showed that the BmK scorpion venom extracts could inhibit the growth of MCF-7 cells by inducing apoptosis and blocking cell cycle in G0/G1 phase. The BmK scorpion venom extracts will be very valuable for the treatment of breast cancer.

The Scorpion Toxin Analogue BmKTX-D33H as a Potential Kv1.3 Channel-Selective Immunomodulator for Autoimmune Diseases

The Kv1.3 channel-acting scorpion toxins usually adopt the conserved anti-parallel β-sheet domain as the binding interface, but it remains challenging to discover some highly selective Kv1.3 channel-acting toxins. In this work, we investigated the pharmacological profile of the Kv1.3 channel-acting BmKTX-D33H, a structural analogue of the BmKTX scorpion toxin. Interestingly, BmKTX-D33H, with its conserved anti-parallel β-sheet domain as a Kv1.3 channel-interacting interface, exhibited more than 1000-fold selectivity towards the Kv1.3 channel as compared to other K⁺ channels (including Kv1.1, Kv1.2, Kv1.7, Kv11.1, KCa2.2, KCa2.3, and KCa3.1). As expected, BmKTX-D33H was found to inhibit the cytokine production and proliferation of both Jurkat cells and human T cells in vitro. It also significantly improved the delayed-type hypersensitivity (DTH) responses, an autoreactive T cell-mediated inflammation in rats. Amino acid sequence alignment and structural analysis strongly suggest that the “evolutionary” Gly11 residue of BmKTX-D33H interacts with the turret domain of Kv1 channels; it appears to be a pivotal amino acid residue with regard to the selectivity of BmKTX-D33H towards the Kv1.3 channel (in comparison with the highly homologous scorpion toxins). Together, our data indicate that BmKTX-D33H is a Kv1.3 channel–specific blocker. Finally, the remarkable selectivity of BmKTX-D33H highlights the great potential of evolutionary-guided peptide drug design in future studies.

Remarkable apoptotic pathway of Hemiscorpius lepturus scorpion venom on CT26 cell line

OBJECTIVE

Scorpion venom, considered as a treasure trove of various bioactive molecules, is a new approach to induce cancer cell death via apoptosis pathways. In the present study, we evaluated for first time the anti-proliferative efficacy of Hemiscorpius lepturus scorpion venom and its pathway on a colon carcinoma cell.

MATERIALS AND METHODS

The CT26 and VERO cell lines were treated with various concentrations of the venom. The IC50 values were estimated by MTT assay test, and the apoptosis was evaluated by flow cytometry. Moreover, RT-PCR analysis was used to investigate the levels of Bax, Bcl2, Trp53, and Casp3 mRNA expression. The mice xenograft model was established to evaluate the therapy efficiency of venom. Some valuable exponential growth parameters were evaluated in treated mice.

RESULT

The scorpion venom inhibited the growth of CT26 cells with an IC50 value about 120 μg/ml. However, VERO cells increased to 896 μg/ml under the same condition. A remarkable apoptotic cells in CT26 cells were revealed by flow cytometry assay. A significant over-expression was observed in Bax, Casp3, and Trp53 and downregulated in Bcl2 mRNA level in tumor tissue after treatment with scorpion venom (p < 0.05). All changes of valuable exponential growth parameters showed a shrinking tumor size.

CONCLUSION

Our findings indicated that Hemiscorpius lepturus venom has a special anti-proliferative effect on CT26 cells via Trp53/Bcl2/Casp3 pathway. Considering its powerful cytotoxic vigor against a colon cancer cell (CT26) and low toxicity to non-tumorigenic cell (VERO), we propose that this venom probably has a specific effect on other colon cancer cells and may turn out to be a novel therapeutic strategy in treating colon cancer.

Scorpion venom peptides: Molecular diversity, structural characteristics, and therapeutic use from channelopathies to viral infections and cancers

Animal venom is an important evolutionary innovation in nature. As one of the most representative animal venoms, scorpion venom contains an extremely diverse set of bioactive peptides. Scorpion venom peptides not only are 'poisons' that immobilize, paralyze, kill, or dissolve preys but also become important candidates for drug development and design. Here, the review focuses on the molecular diversity of scorpion venom peptides, their typical structural characteristics, and their multiple therapeutic or pharmaceutical applications in channelopathies, viral infections and cancers. Especially, the group of scorpion toxin TRPTx targeting transient receptor potential (TRP) channels is systematically summarized and worthy of attention because TRP channels play a crucial role in the regulation of homeostasis and the occurrence of diseases in human. We also further establish the potential relationship between the molecular characteristics and functional applications of scorpion venom peptides to provide a research basis for modern drug development and clinical utilization of scorpion venom resources.

In vitro determination of the efficacy of scorpion venoms as anti-cancer agents against colorectal cancer cells: a nano-liposomal delivery approach

The use of liposomes in biological and medicinal sciences is a relatively new approach. The liposomal strategy greatly depends on the technological advancement in the formation of vesicles of various sizes and properties. In the current study, we encapsulated the venoms obtained from medically important scorpions such as Androctonus bicolor (AB), Androctonus crassicauda (AC), and Leiurus quinquestriatus (LQ). To begin with, our first and foremost aim was to prepare biocompatible and biodegradable nanovesicles. Additionally, we intended to enhance the anti-cancer potential of these encapsulated venoms. The liposomal venoms were prepared by rehydration and dehydration methods. Morphology, particle size, and size distribution of the liposomes were examined by scanning electron microscope (SEM), transmission electron microscope (TEM), and Zetasizer. We found that the prepared liposomes had a smooth surface and a spherical/ovoid shape and existed mainly as single unilamellar vesicles (SUVs). Furthermore, the liposomal formulation of all three venoms exhibited excellent stability and good encapsulation efficiency (EE). Additionally, the anti-cancer potential of the encapsulated venoms was also evaluated on a colorectal cancer cell line (HCT-8). The venom-loaded liposomes showed elevated anti-cancer properties such as low rate of cell survival, higher reactive oxygen species (ROS) generation, and enhancement in the number of apoptotic cells. In addition to this, cell cycle analysis revealed G0/G1 enrichment upon venom treatment. The effect of treatment was more pronounced when venom-liposome was used as compared to free venom on the HCT-8 cell line. Furthermore, we did not observe any interference of liposomal lipids used in these preparations on the progression of cancer cells. Considering these findings, we can conclude that the encapsulated scorpion venoms exhibit better efficacy and act more vigorously as an anti-cancer agent on the colorectal cancer cell line when compared with their free counterpart.

SPECT imaging and radionuclide therapy of glioma using 131I labeled Buthus martensii Karsch chlorotoxin

Gliomas, the most prevalent type of brain tumor in adults, are associated with high rates of morbidity and mortality. Recent studies on ¹³¹I labeled scorpion toxins suggest they can be developed as tumor-specific agents for glioma diagnosis and treatment. This study investigated the potential of ¹³¹I labeled Buthus martensii Karsch chlorotoxin (¹³¹I-BmK CT) as a new approach for targeted imaging and therapy of glioma. The results showed that ¹³¹I can be successfully linked to BmK CT with satisfactory radiochemical purity and stability and that ¹³¹I-BmK CT markedly inhibited glioma cell growth in a dose and time dependent manner, with significant accumulation in glioma cells in vitro. Persistent intratumoral radioiodine retention and specific accumulation of ¹³¹I-BmK CT were observed in C6 glioma tumor, which was clearly visualized by SPECT imaging. Both intratumoral and intravenous injections of ¹³¹I-BmK CT could result in significant tumor inhibition efficacy and prolonging the lifetime of tumor-bearing mice. Based on these promising results, it is concluded that ¹³¹I-BmK CT has the potential to be explored as a novel tool for SPECT imaging and radionuclide therapy of glioma.

Outside the box--novel therapeutic strategies for glioblastoma

Standard approaches to therapy for malignant glioma provide modest improvement of progression-free survival and overall survival. Almost all patients experiencing glioblastoma eventually progress, and no cure is currently available. During the last decade, we have witnessed a 30% improvement in 2-year overall survival rates, yet glioblastoma continues to cause approximately 13,000 cancer-related deaths in the United States annually. Thus, novel therapies need to be investigated alongside continued development of currently available radiotherapy and chemotherapy options. Because glioblastoma does not typically metastasize outside the brain, development of unique local therapies that are not available for other cancers is feasible. Experimental agents, like scorpion venom-derived chlorotoxin, have been successfully applied in local therapy for glioblastoma. In addition, multiple new gene therapy approaches are emerging for both local and systemic glioblastoma therapy. Lastly, alternating electric fields are being introduced to cancer therapy. This review will discuss these "nonstandard"--outside the box--modalities for therapy for malignant glioma.

Targeted molecular therapy for malignant gliomas

Advances in our understanding of the molecular changes and resultant cellular effects in malignant glioma are expanding the opportunities for novel targeted therapies. At present, chemotherapy and radiation followed by chemotherapy with nonselective cytotoxic agents is emerging as a standard treatment option for patients with malignant glioma. Unfortunately significant improvements in response and survival have not occurred for the majority of patients. The continued improvement in patient outcomes will require the incorporation of glioma-specific therapies either in the form of compounds specifically targeted to glioma-specific receptors or that inhibit signaling pathways promoting glioma survival and progression.

A neurotoxinological approach to the treatment of obstructive sleep apnoea

Current treatment approaches to the problem of obstructive sleep apnoea (OSA) have limitations. Specifically, invasive anatomical-based surgery and dental appliances typically do not alleviate obstruction at an acceptable rate, and compliance to continuous positive airway pressure (CPAP) devices is frequently suboptimal. Neurotoxinological treatment approaches are widespread in the field of medicine, but as yet have not been evaluated as a treatment for sleep-disordered breathing. In this review, it is argued that despite widespread recognition of the loss of upper airway (UA) muscular tone and/or reflexes in the expression of OSA, most treatment interventions to date have focused on anatomical principles alone. Several hypothesised neurotoxinological interventions aimed at either enhancing UA neuromuscular tone and/or reflexes are proposed, and some preliminary data is presented. Although in its early infancy, with considerable toxicity studies in animals yet to be done, a neurotoxinological approach to the problem of OSA holds promise as a future treatment, with the potential for both high effectiveness and patient compliance.

Leurieus quinquestriatus scorpion venom ameliorates adjuvant-induced arthritis in rats: Modulating JAK/STAT/RANKL signal transduction pathway

Leurieus quinquestriatus (LQ) is a type of Egyptian scorpions. Prior studies have established the potential use of scorpion venoms in treating several autoimmune diseases. Therefore, the current study investigates the possible pharmacological effect of LQ venom in CFA-induced arthritis - through different mechanisms - by assessing different serum and tissue parameters. This study was divided into two phases: phase I was conducted to determine the lowest therapeutic dose of LQ scorpion venom, whereas phase II investigated the potential therapeutic effect of the chosen dose of LQ venom on induced arthritis through different mechanisms. The Wistar albino rats were divided equally and randomly into normal control group, LQ control group, arthritis control group, infliximab-treated group, and LQ-treated group. On day 20, blood and tissue samples were collected for further analysis of serum and tissue biomarkers as well as histopathological examination. The results revealed a potential therapeutic effect of LQ venom on arthritic-induced rats through a significant decrease in Rheumatoid Factor, Janus Kinase, Signal transducers and activators of transcription, Receptor activator of nuclear factor Kappa-B ligand, Tumor Necrosis Factor-alpha, Interleukin-6, Nuclear factor kappa-light-chain-enhancer of activated B cells and Malondialdehyde by 57%, 66%, 64%, 62%, 75%, 59%, 38%, and 69%, respectively as well as a significant increase in reduced glutathione, and Nuclear factor erythroid 2-related factor 2 by 102% and 360%, respectively. Histopathological examination of knee joint and spleen also revealed a substantial improvement, indicating the possible utilization of LQ venom in the treatment of rheumatoid arthritis.

A Cytochrome c-Chlorotoxin Hybrid Protein as a Possible Antiglioma Drug

Malignant gliomas are the most lethal form of primary brain tumors. Despite advances in cancer therapy, the prognosis of glioma patients has remained poor. Cytochrome c (Cytc), an endogenous heme-based protein, holds tremendous potential to treat gliomas because of its innate capacity to trigger apoptosis. To this end, a hybrid cytochrome c-chlorotoxin (Cytc-CTX) protein was biosynthesized to enable cellular uptake of the cell impenetrable Cytc using CTX transporters. A nucleotide sequence containing 1 : 1 Cytc and CTX was constructed and separated by a hexahistidine-tag and an enterokinase cleavage site. The sequence was cloned into a pBTR1 plasmid, expressed in Escherichia coli, purified via 2-dimensional chromatography. The identity and size of the protein were determined by Western blot and mass spectrometry. Cytc in this soluble hybrid protein has similar structure and stability as human Cytc and the hybrid protein is endocytosed into a glioma cell line, while displaying potent cytotoxicity and a favorable therapeutic index. Its facile, low-cost, and high yield synthesis, biocompatibility, and robustness suggest that the hybrid protein is a promising candidate for antiglioma drug evaluation.

Case Report: Fatal Scorpion Envenomation in a Shuar Child by Tityus cisandinus from Amazonian Ecuador: A Call for Specific Antivenom Availability in the Amazon Basin

Envenomation by scorpions belonging to the genus Tityus can be life threatening in the Americas, particularly in the Amazon Basin. We report a 4-month-old Ecuadorean boy of Shuar origin stung by a scorpion identified as Tityus cisandinus in the Amazonian province of Morona Santiago, presenting with pulmonary edema and systemic inflammation. We administered immunotherapy using the scorpion antivenom available in Ecuador, of Mexican origin (anti-Centruroides). Catecholamine discharge-related events such as hyperglycemia and thrombocytosis were resolved after treatment but leukocytosis did not, suggesting that factors associated with the sting-admission delay and specificity of antivenom played a role in the envenomation outcome. Cardiorespiratory arrest determined a fatal outcome, despite specific maneuvers. The case severity and the limited supply of nonspecific scorpion antivenoms in problematic areas of Amazonian Ecuador and elsewhere in northwestern Amazonia are discussed in regard to the need for specific therapeutic immunoglobulins in the area and in the Amazon Basin as a whole.

Study of Anti-Inflammatory and Analgesic Activity of Scorpion Toxins DKK-SP1/2 from Scorpion Buthus martensii Karsch (BmK)

Buthus martensii Karsch (BmK), is a kind of traditional Chinese medicine, which has been used for a long history for the treatment of many diseases, such as inflammation, pain and cancer. In this study, DKK-SP1/2/3 genes were screened and extracted from the cDNA library of BmK. The DKK-SP1/2/3 were expressed by using plasmid pSYPU-1b in E. coli BL21, and recombinant proteins were obtained by column chromatography. In the xylene-induced mouse ear swelling and carrageenan-induced rat paw swelling model, DKK-SP1 exerted a significant anti-inflammatory effect by inhibiting the expression of Nav1.8 channel. Meanwhile, the release of pro-inflammatory cytokines (COX-2, IL-6) was decreased significantly and the release of anti-inflammatory cytokines (IL-10) were elevated significantly. Moreover, DKK-SP1 could significantly decrease the Nav1.8 current in acutely isolated rat DRG neurons. In the acetic acid-writhing and ION-CCI model, DKK-SP2 displayed significant analgesic activity by inhibiting the expression of the Nav1.7 channel. Moreover, DKK-SP2 could significantly inhibit the Nav1.7 current in the hNav1.7-CHO cells.

Inhibitory effects of recombinant neurotoxin BmK IM on seizures induced by pentylenetetrazol in Rats

OBJECTIVE

To elucidate the inhibitory effects of recombinant Chinese scorpion neurotoxin BmK IM on seizures induced by pentylenetetrazol (PTZ) and the possible mechanism.

METHODS

After purifying recombinant BmK IM from an E. coli cell line, its toxicity (both LD50 and minimum lethal dose) on rats was determined. BmK IM was then microinjected into the CA3 region of the right hippocampus and its ability to inhibit the effects of an intraperitoneal injection of PTZ was assessed. The effects of BmK IM on the electrophysiological properties of isolated CA3 pyramidal neurons were then studied using whole-cell patch clamp techniques.

RESULTS

BmK IM can significantly prolong the latent period of epileptic seizures, decrease the degree of seizures, and decrease the frequency of epileptiform discharges induced by PTZ. At the same time, 24h after injection of BmK IM into the hippocampal tissue, BmK IM significantly reduces the concentration of the neurotransmitter glutamate and alleviates PTZ-induced lesions in the hippocampus. Whole-cell patch clamp recordings indicate that BmK IM inhibits INa of rat hippocampal neurons in a dose-dependent manner. BmK IM significantly shifts the activation curve of INa in a positive direction, indicating that BmK IM enhances the threshold potential of INa.

CONCLUSIONS

BmK IM has significant anti-epileptic properties, and may prove useful as a drug in the therapy of epilepsy. The inhibitory effects of BmK IM on seizures caused by pentylenetetrazol might depend on reductions in the release of presynaptic glutamate via the blocking of Na+ channels.