Scorpion venom induces glioma cell apoptosis in vivo and inhibits glioma tumor growth in vitro

Investigation on the mechanisms of scorpion venom in hepatocellular carcinoma model mice via untargeted metabolomics profiling

Metabolic reprogramming is frequently accompanied by hepatocellular carcinoma (HCC) progression. Disrupted metabolites act as potential biomarkers and drug therapeutic targets for HCC. Peptide extract of scorpion venom (PESV) induces cytotoxic anti-proliferative effects and apoptosis in tumors. However, the action mechanisms of PESV remain unknown. This study aimed to explore the serum metabolic profiles of tumor-bearing mouse model. We generated an orthotopic HCC xenograft mouse model by implanting H22 cells into the left hepatic lobe of male C57BL/6 mice. After surgery, the mice were assigned to two groups randomly: PESV (PESV-treated 40 mg/kg daily, i.g.; n = 6) and control (treated with the solvent equally for 14 d, n = 6) groups. Based on an untargeted metabolomics approach using ultra-high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry, differential metabolites were screened via univariate and multivariate data analyses. A total of 48 differential metabolites in negative ion mode and 63 in positive ion mode were identified in the serum samples. Furthermore, metabolic pathway analysis revealed that aminoacyl-tRNA biosynthesis, amino acid pathway, glutathione metabolism, protein transports, protein digestion and absorption, and cAMP signaling pathways play vital roles in PESV-induced inhibition of tumors. These findings highlight the distinct changes in the metabolic profiles of HCC-bearing mice after PESV treatment, suggesting the potential of the identified metabolic molecules as therapeutic targets for HCC.

Bioactive Properties of Venoms Isolated from Whiptail Stingrays and the Search for Molecular Mechanisms and Targets

The venom-containing barb attached to their 'whip-like' tail provides stingrays a defensive mechanism for evading predators such as sharks. From human encounters, dermal stingray envenomation is characterized by intense pain often followed by tissue necrosis occurring over several days to weeks. The bioactive components in stingray venoms (SRVs) and their molecular targets and mechanisms that mediate these complex responses are not well understood. Given the utility of venom-derived proteins from other venomous species for biomedical and pharmaceutical applications, we set out to characterize the bioactivity of SRV extracts from three local species that belong to the Dasyatoidea 'whiptail' superfamily. Multiple cell-based assays were used to quantify and compare the in vitro effects of these SRVs on different cell lines. All three SRVs demonstrated concentration-dependent growth-inhibitory effects on three different human cell lines tested. In contrast, a mouse fibrosarcoma cell line was markedly resistant to all three SRVs, indicating the molecular target(s) for mediating the SRV effects are not expressed on these cells. The multifunctional SRV responses were characterized by an acute disruption of cell adhesion leading to apoptosis. These findings aim to guide future investigations of individual SRV proteins and their molecular targets for potential use in biomedical applications.

Investigating the inhibitory and penetrating properties of three novel anticancer and antimicrobial scorpion peptides via molecular docking and molecular dynamic simulation

The two types of bladder cancer, muscle invasive and non-muscle invasive (NMIBC), are among the most prevalent cancers worldwide. Despite this, even though muscle-invasive bladder cancer is more deadly, NMIBC requires more therapy due to a greater recurrence rate and more extended and expensive care. Immunotherapy, intravesical chemotherapy, cystoscopy, and transurethral resection (TUR) are among the treatments available. Crude scorpion venomand purified proteins and peptides, can suppress cancer metastasis in an in vitro or in vivo context, suppress cancer growth, halt the cell cycle, and cause cell apoptosis, according to an increasing number of experimental and preclinical studies. In this research, three novels discovered peptides (P2, P3 and P4. ProteomeXchange: PXD036231) from Buthotus saulcyi and, Odontobuthus doriae scorpions were used along with a peptide called pantinin (as a control). The phylogenetic tree showed that the peptides belong to Chaperonin HSP60, Chrysophsin2 and Pheromone-binding protein2, respectively. These peptides were docked with four known antigens, BAGE, BLCAP, PRAME and ROR1 related to bladder cancer and three bacterial antigens FliC, FliD and FimH to investigate their antimicrobial and anticancer properties. The results showed that peptides 2 and 3 have the best binding rate. The MD simulation results also confirmed the binding of peptides 2 and 3 to antigens. The penetration power of peptides 2 and 3 in the membrane of cancer cells and bacterial cells was also simulated, and the results of RMSD and PD confirmed it. QSAR suggests that peptides 2 and 3 can act as anti-cancer and anti-microbial peptides.Communicated by Ramaswamy H. Sarma.

Peptides with Diverse Functions from Scorpion Venom: A Great Opportunity for the Treatment of a Wide Variety of Diseases

Toxicology Research Center, Medical Basic Sciences Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran

The venom glands are a rich source of biologically important peptides with pharmaceutical properties. Scorpion venoms have been identified as a reservoir for components that might be considered as great candidates for drug development. Pharmacological properties of the venom compounds have been confirmed in the treatment of different disorders. Ion channel blockers and AMPs are the main groups of scorpion venom components. Despite the existence of several studies about scorpion peptides, there are still valuable components to be discovered. Additionally, owing to the improvement of proteomics and transcriptomics, the number of peptide drugs is steadily increasing, which reflects the importance of these medications. This review evaluates available literatures on some important scorpion venom peptides with pharmaceutical activities. Given that the last three years have been dominated by the COVID-19 from the medical/pharmaceutical perspective, scorpion compounds with the potential against the coronavirus 2 (SARS-CoV-2) are discussed in this review.

Antiproliferative and antioxidant properties of nematocysts crude venom from jellyfish Acromitus flagellatus against human cancer cell lines

This study aimed to investigate the antiproliferative and antioxidant properties of crude venom from the nematocyst of Jellyfish Acromitus flagellates on human lung cancer (A549) and liver cancer (HepG2) cell lines. The prepared crude venom was subjected to analyses of the biochemical constituents, protein profiles, antioxidant and anticancer activities by standard methods. The extracted venom was pale-yellow in color and viscous/sticky. The biochemical composition such as, protein (1.547 mg/ml), lipid (0.039 mg/ml) and carbohydrate (0.028 mg/ml) was estimated. Protein profiles were determined by SDS PAGE, the result revealed that the molecular weight range from 205 - 3.5 kDa. The free radical scavenging activity was analyzed by the reducing potential (56.36%), DPPH (72.47%), hydroxyl (68.50%), superoxide anion (65.75%), and nitric oxide (33.04%). The cell viability was observed by using different concentrations (20 to 100 µg/ml) of crude venom on A549 and HepG2 cancer cell lines and the IC50 values were recorded in (60 μg/ml and 40 μg/ml) respectively, while it had none cytotoxic effects on Vero cell line up to the concentration of 90 μg/ml. These results suggest that crude venom from nematocyst of A. flagellatus possesses anti-cancer activity and able to develop novel drugs on marine-derived compounds.

Moving Pieces in a Cellular Puzzle: A Cryptic Peptide from the Scorpion Toxin Ts14 Activates AKT and ERK Signaling and Decreases Cardiac Myocyte Contractility via Dephosphorylation of Phospholamban

Cryptic peptides (cryptides) are biologically active peptides formed after proteolysis of native precursors present in animal venoms, for example. Proteolysis is an overlooked post-translational modification that increases venom complexity. The tripeptide KPP (Lys-Pro-Pro) is a peptide encrypted in the C-terminus of Ts14-a 25-mer peptide from the venom of the Tityus serrulatus scorpion that has a positive impact on the cardiovascular system, inducing vasodilation and reducing arterial blood pressure of hypertensive rats among other beneficial effects. A previous study reported that KPP and its native peptide Ts14 act via activation of the bradykinin receptor B2 (B2R). However, the cellular events underlying the activation of B2R by KPP are unknown. To study the cell signaling triggered by the Ts14 cryptide KPP, we incubated cardiac myocytes isolated from C57BL/6 mice with KPP (10^-7 mol·L^-1) for 0, 5, or 30 min and explored the proteome and phosphoproteome. Our results showed that KPP regulated cardiomyocyte proteins associated with, but not limited to, apoptosis, muscle contraction, protein turnover, and the respiratory chain. We also reported that KPP led to AKT phosphorylation, activating AKT and its downstream target nitric oxide synthase. We also observed that KPP led to dephosphorylation of phospholamban (PLN) at its activation sites (S16 and T17), leading to reduced contractility of treated cardiomyocytes. Some cellular targets reported here for KPP (e.g., AKT, PLN, and ERK) have already been reported to protect the cardiac tissue from hypoxia-induced injury. Hence, this study suggests potential beneficial effects of this scorpion cryptide that needs to be further investigated, for example, as a drug lead for cardiac infarction.

Mesobuthus eupeus venom induced injury in the colorectal carcinoma cell line (HT29) through altering the mitochondria membrane stability

Objective(s):

The purpose of this study was to investigate cytotoxicity and membrane toxicity effects induced by Mesobuthus eupeus venom (MEV) on the HT-29 cell line.

Materials and Methods:

To determine the in vitro cytotoxicity via MTT assays, HT-29 (as cancer cell line) and Hek-293T (as normal cell) were treated through different concentrations of MEV, and cytotoxicity effects were then measured through assessment of mitochondrial membrane potential (ΔΨm), reactive oxygen species (ROS) generation, and apoptosis induction. The colony formation assay was performed to measure the antiproliferative effect of MEV on HT-29 cells. Nuclei alterations were also observed during apoptosis following DAPI staining. Besides, atomic force microscopy (AFM) was used to detect alterations in morphology and ultrastructure of the cells at a nanoscale level.

Results:

According to MTT and clonogenic assays, MEV caused a significant decrease in cell viability and proliferation of HT-29 cells while it did not have any impact on normal cells and the IC50 value was found to be 10 µg/ml. Induction of apoptosis was also confirmed by flowcytometric analysis in HT-29 cells. Moreover, the results indicated that MEV had led to a suppression of proliferation and induction of apoptosis through increased ROS and depolarization of mitochondria. Furthermore, AFM imaging demonstrated apoptosis cell death after being treated with MEV in HT-29 cells.

Conclusion:

This study showed that MEV had an antiproliferative effect on HT-29 cells by inducing apoptosis through the mitochondria signaling pathway. These findings suggested that MEV could be used as a promising natural remedy for cancer treatment.

Voltage-Gated K+/Na+ Channels and Scorpion Venom Toxins in Cancer

Ion channels have recently been recognized as novel therapeutic targets in cancer research since they are overexpressed in different histological tissues, and their activity is linked to proliferation, tumor progression, angiogenesis, metastasis, and apoptosis. Voltage gated-potassium channels (VGKC) are involved in cell proliferation, cancer progression, cell cycle transition, and apoptosis. Moreover, voltage-dependent sodium channels (VGSC) contribute to decreases in extracellular pH, which, in turn, promotes cancer cell migration and invasion. Furthermore, VGSC and VGKC modulate voltage-sensitive Ca²⁺ channel activity by controlling the membrane potential and regulating Ca²⁺ influx, which functions as a second messenger in processes related to proliferation, invasion, migration, and metastasis. The subgroup of these types of channels that have shown a high oncogenic potential have become known as “oncochannels”, and the evidence has highlighted them as key potential therapeutic targets. Scorpion venoms contain a high proportion of peptide toxins that act by modulating voltage-gated Na⁺/K⁺ channel activity. Increasing scientific data have pointed out that scorpion venoms and their toxins can affect the activity of oncochannels, thus showing their potential for anticancer therapy. In this review, we provide an update of the most relevant voltage-gated Na⁺\K⁺ ion channels as cellular targets and discuss the possibility of using scorpion venom and toxins for anticancer therapy.

A. crassicauda, M. eupeus and H. lepturus scorpion venoms initiate a strong in vivo anticancer immune response in CT26-tumor mice model

In the present in vivo study the anticancer efficacy of the venoms from Androctonus crassicauda, Messobuthus eupeus and Hemiscorpius lepturus scorpions was investigated. In addition, we attempted to clarify whether the immune system is involved in this activity. Initially, the LD₅₀ of the venoms from these scorpions were determined and their 0.1 and 0.2 LD₅₀ were calculated. The toxicity of 0.1 and 0.2 LD₅₀ was tested on healthy mice by daily SC administration of these venoms for 12 consecutive days. CT26 cells were inoculated by SC route in BALB/c mice to establish a sold tumor, and ten days later, the mice were treated with 0.1 and 0.2 LD₅₀ doses of the venoms on daily basis for 12 consecutive days. The tumor volume was measured every 4 days. At day 13, the tumors from untreated-control and venom-treated groups were removed, weighed, and assessed by histopathological and immunohistochemical techniques. In addition, the levels of mRNA expression of IL-12, IFN-γ and IL-1β were measured by real-time PCR. All the venoms induced anticancer effects as evidenced by significant inhibition in tumor growth; significant increases in inflammatory and CD⁺-T cells and expression of mRNA IL-12 and IFN-γ in tumor microenvironment of venom-treated as compared to untreated-control. These findings demonstrated, for the first time, that sub-lethal doses of the venoms from these scorpions induce their in vivo anticancer effects by stimulating the immune system. Further studies, specifically designed to identify these active constituents are recommended.

Scorpion Venom: New Promise in the Treatment of Cancer

Cancer is a public health problem due to its high worldwide morbimortality. Current treatment protocols do not guarantee complete remission, which has prompted to search for new and more effective antitumoral compounds. Several substances exhibiting cytostatic and cytotoxic effects over cancer cells might contribute to the treatment of this pathology. Some studies indicate the presence of such substances in scorpion venom. In this review, we report characteristics of the principal scorpion venom components found in recent literature and their potential activity against tumor cells.  There are different toxin groups present in the venom, and it seems that their mode of actions involves ionic channel blocking, disruption of the cell membrane integrity and damage to internal cell organelles.  These properties make good prospects for studies on drugs and adjuvants in cancer treatment.

Peptides with therapeutic potential in the venom of the scorpion Buthus martensii Karsch

The scorpion Buthus martensii Karsch (BmK) has generated significant interest due to the presence of biologically active peptides in its venom. In the past decade, dozens of different peptides from BmK have been identified. Most of the peptides are neurotoxins and are responsible for the toxicity of BmK venom. Other peptides, including neurotoxins and non-disulfide-bridged peptides, show potential anticancer, antimicrobial, analgesic, and anti-epileptic therapeutic effects. These peptides are attractive candidates for drug development, and peptide derivatives have also been designed to enhance their therapeutic potential, such as ADWX-1 and Kn2-7. In this review, we provide an overview of the most promising peptides found in BmK venom and of modified peptide derivatives showing therapeutic potential.

Polypeptides secreted from the columnar vesicles of the sea anemone Bunodosoma cangicum and their in vivo effects on Caenorhabditis elegans

In this study we provide new evidence that the columnar vesicles of the sea anemone Bunodosoma cangicum are toxic in vivo and contain at least two active polypeptides, a neurotoxic and an apoptosis inducing polypeptide. Here we show that it is also an effective inducer of apoptosis in vivo in the nematode Caenorhabditis elegans. In addition, the anemone peptides rapidly paralyze C. elegans, and set in motion a sequence of events that result in the complete dissolution of the internal organs in adult animals within 60 min. Nematodes that survive the toxin treatment exhibit a decreased reproductive capacity. Interestingly, adult animals appear to be much more susceptible to the effects of the toxins than larval stages, suggesting possible developmentally dependent targets of the toxins. Here we also provide chemical characterization of the compounds through chromatographic analysis and mass spectrometry. Gel filtration chromatography coupled with reverse phase HPLC shows that our partially purified extract contains at least two principle components. Additionally, MALDI-TOF mass spectrometry analysis of our extract shows three principal compounds at 814.6, 2914.1, and 4360.3 m/z plus three other minor components or fragments. Mass spectrometry analysis also indicates the presence of three disulfide bridges. Which is in agreement with other characterizations of anemone venoms.

Scorpion Venom Causes Upregulation of p53 and Downregulation of Bcl-xL and BID Protein Expression by Modulating Signaling Proteins Erk1/2 and STAT3, and DNA Damage in Breast and Colorectal Cancer Cell Lines

Scorpion venoms efficiently block the normal neurotransmitter signaling pathway by prejudicing the ion channel operating mechanism in the body system. Besides its negative effect, venoms also possess some beneficial qualities for humans. They have also been shown to exhibit anticancer properties in various cancer types. This unique property of the venom as an anticancer agent is mainly a result of its role in initiating apoptosis and inhibiting several signaling cascade mechanisms that promote cancer cell proliferation and growth. In this study, we examine the effect of venom on phenotypic changes as well as changes at the molecular levels in colorectal and breast cancer cell lines. A dramatic decrease in cell invasion was observed in both cancer cell lines on venom treatment. Additionally, there was decrease in IL-6, RhoC, Erk1/2, and STAT3 in venom-treated cell lines, providing strong evidence of its anticancer properties. Furthermore, decrease in the expression of antiapoptotic proteins and also upregulation of proapoptotic ones by these lines were observed on venom treatment. Moreover, a vivid picture of DNA damage was also detected on venom treatment. In conclusion, scorpion venom possesses significant potential as an anticancer agent against colorectal and breast cancer cell lines.

Purificación parcial de péptidos y actividad citotóxica del veneno T. macrochirus

Introducción. Los venenos de escorpiones poseen péptidos con actividad neurotóxica, que actúan principalmente en canales iónicos del sistema nervioso de insectos y mamíferos. También se ha determinado acción citolítica y anticancerígena, características biológicas que aún no se han reportado sobre el veneno del escorpión Tityus macrochirus.Objetivo. Evaluar si tanto el veneno total de T. macrochirus, como la fracción de péptidos parcialmente purificados disminuyen el porcentaje de viabilidad de diferentes líneas celulares provenientes de tumores.Materiales y métodos. A partir del veneno de T. macrochirus, obtenido por estimulación eléctrica, se utilizaron métodos cromatográficos, electroforéticos y de centrifugación con Amicon, para la identificación y purificación parcial de sus péptidos. Los ensayos de actividad citotóxica del veneno y de la fracción de péptidos, se realizaron sobre líneas celulares provenientes de tumores, por el método colorimétrico de MTT.Resultados. El veneno de T. macrochirus, posee péptidos con pesos moleculares entre 3 a 10kDa, que fueron parcialmente purificados por medio de ultrafiltración y evaluados por RP¬HPLC. Los ensayos de citotoxicidad con el veneno total T. macrochirus, mostraron mayor disminución de viabilidad en la línea celular PC3, con respecto a las demás líneas celulares evaluadas y la fracción parcialmente purificada de péptidos, logró disminuir la viabilidad en la línea celular HeLa.Conclusión. En el veneno de T. macrochirus se encuentran péptidos que presentaron actividad citotóxica sobre algunas líneas celulares provenientes de tumores, observándose algún tipo de selectividad frente a las diferentes líneas celulares evaluadas.

Cytotoxic activity of Androctonus australis hector venom and its toxic fractions on human lung cancer cell line

Background

Several studies have showed that animal venoms are a source of bioactive compounds that may inhibit the growth of cancer cells, which makes them useful agents for therapeutic applications. Recently, it was established that venom toxins from scorpions induced cytotoxic, antiproliferative and apoptogenic effects on cancer cells. Therefore, the present study aims to investigate the cytotoxic activity of Androctonus australis hector (Aah) scorpion venom and its toxic fractions (FtoxG-50 and F3) on NCI-H358 human lung cancer cells.

Methods

The cytotoxic and antiproliferative activities were estimated using MTT assay, lactate dehydrogenase release and clonogenic assays. Apoptosis was evaluated by Hoechst 33258 staining, DNA fragmentation assay and caspase-3 activity. Oxidative stress was analyzed by reactive oxygen species, nitric oxide, malondialdehyde and protein carbonyl levels along with assessment of antioxidant status. In addition, alteration of mitochondrial membrane potential was analyzed by JC1 fluorescent dye.

Results

The present findings showed that F3 fraction was more cytotoxic towards NCI-H358 lung cancer cells with an IC₅₀ of 27.05 ± 0.70 μg/mL than venom alone (396.60 ± 1.33 μg/mL) and its toxic fraction FtoxG-50 (45.86 ± 0.91 μg/mL). Nevertheless, F3 fraction was not cytotoxic at these concentrations on normal human lung fibroblast MRC-5 cells. Inhibition of NCI-H358 cell proliferation after F3 fraction exposure occurred mainly by apoptosis as evidenced by damaged nuclei, significant DNA fragmentation level and caspase-3 activation in a dose dependent manner. Moreover, F3 fraction enhanced oxidative and nitrosative stress biomarkers and dissipated mitochondrial membrane potential in lung cancer cells along with significant depletion in cellular enzymatic and non-enzymatic antioxidants. Further, the apoptosis induced by F3 fraction was markedly prevented by the antioxidant N-acetylcysteine (NAC) suggesting the potential mechanism of oxidative stress.

Conclusion

These findings suggest that F3 fraction could induce apoptosis in lung cancer cells through involvement of oxidative stress and mitochondrial dysfunction. Hence, these properties make F3 fraction a promising candidate for development of new anticancer agents.

[Ants: a chemical library of anticancer molecules]

Animal venoms are complex mixtures containing simple organic molecules, proteins, peptides, and other bioactive elements with extraordinary biological properties associated with their ability to act on a number of molecular receptors in the process of incapacitating their target organisms. In such a context, arthropod venoms are invaluable sources of bioactive substances, with therapeutic interest but the limited availability of some venom such as those from ants, has restricted the potential that these biomolecules could represent. We investigated for the first time transcriptomic expression from the ant species Tetramorium bicarinatum. Four hundred randomly selected clones from cDNA libraries were sequenced and a total of 374 expressed sequence tags (ESTs) were generated. Based on the results of BLAST searches, these sequences were clustered and assembled into 269 contigs. About 72% (269) of these matched BLASTx hits with an interesting diversity and unusual abundance of cellular transcripts (48%) related to gene and protein expression reflecting the specialization of this tissue. In addition, transcripts encoding transposases were relatively highly expressed (14%). It may be that transposable elements are present and that their presence accounts for some of the variation in venom toxins. About twenty per cent of the ESTs were categorized as putative toxins, the major part represented by allergens (48% of the total venom toxins) such as pilosulin 5, sol i 3 and Myp p I and II. Several contigs encoding enzymes, including zinc-metalloproteases (17%) that are likely involved in the processing and activation of venom proteins/peptides, were also identified from the library. In addition, a number of sequences (8%) had no significant similarity to any known sequence which indicates a potential source of for the discovery of new toxins. In order to provide a global insight on the transcripts expressed in the venom gland of the Brazilian ant species Tetramorium bicarinatum and to unveil the potential of their products, high-throughput expressed sequence tags were generated using Illumina paired-end sequencing technology. A total of 212 371 758 pairs of quality-filtered, 100-base-pair Illumina reads were obtained. The de novo assemblies yielded 36 042 contigs for which 27 873 have at least one predicted ORF among which 59.77% produce significant hits in the available databases. The investigation of the read mapping toxin class revealed and confirmed a high diversification with the major part consistent with the classical hymenopteran venom protein signature represented by venom allergen (33.3%) followed by a diverse toxin-expression profile including several distinct isoforms of phospholipase A1 and A2, venom serine protease, hyaluronidase, protease inhibitor and secapin. Moreover, our results revealed for the first time the presence of toxin-like peptides that have been previously identified from unrelated venomous animals such as waprin-like (snakes) and agatoxins (spiders and conus). These studies provide a first insight of the gene expression scenario of the venom gland of T. bicarinatum which might contribute to acquiring a more comprehensive view about the origin and functional diversity of venom proteins of this ant. Based on such results, we conducted cytotoxic tests from the crude venom of T.bicarinatum ant and reported toxic effect on tumoral cells lines from one of the fifth of the most frequently occurring cancers with a 3-year survival rate of only 30%. In such a context, new therapeutic strategies are essential and the discovery of new molecules in ant venom could be one possible avenue. Thus our project aims to characterize, from the crude venom of T.bicarinatum, the molecule(s) which have potential anti-cancerous toxicity as well as their mechanisms of action.

In vitro studies with renal proximal tubule cells show direct cytotoxicity of Androctonus australis hector scorpion venom triggered by oxidative stress, caspase activation and apoptosis

Scorpion envenomation injures a number of organs, including the kidney. Mechanisms proposed to explain the renal tubule injury include direct effects of venom on tubule epithelial cells, as well as indirect effects of the autonomic nervous system, and inflammation. Here, we report direct effects of Androctonus australis hector (Aah) scorpion venom on the viability of Renal Proximal Tubule (RPT) cells in vitro, unlike distal tubule and collecting duct cells. Extensive NucGreen nuclear staining was observed in immortalized rabbit RPT cells following treatment with Aah venom, consistent with cytotoxicity. The involvement of oxidative stress is supported by the observations that 1) anti-oxidants mitigated the Aah venom-induced decrease in the number of viable RPT cells, and 2) Aah venom-treated RPT cells were intensively stained with the CellROX(®) Deep Red reagent, an indicator of Reactive Oxygen Species (ROS). Relevance to normal RPT cells is supported by the red fluorescence observed in Aah venom treated primary rabbit RPT cell cultures following their incubation with the Flica reagent (indicative of caspase activation and apoptosis), and the green fluorescence of Sytox Green (indicative of dead cells).

Antiproliferative activity of marine stingray Dasyatis sephen venom on human cervical carcinoma cell line

BACKGROUND

Venoms comprise mixtures of numerous bioactive compounds that have a wide range of pharmacologic actions. Toxins from venomous animals have attracted the attention of researchers because of their affinity for primary sites responsible for lethality and their efficacy at extremely low concentrations. The venoms of marine stingrays have not been extensively studied and limited data is available on them. The present study aims to evaluate the antiproliferative and biochemical properties of the venom obtained from a species of marine stingray (Dasyatis sephen) on human cervical cancer cell line HeLa.

METHODS

The antiproliferative effect of D. sephen venom was determined by MTT assay, and the oxidative stress was determined by lipid peroxidation method along with assessment of changes in the enzymatic and non-enzymatic antioxidant status. We observed intracellular reactive oxygen species (ROS) levels by DCFH-DA method, mitochondrial membrane potential alterations by rhodamine 123 staining and apoptotic morphological changes by acridine orange/ethidium bromide dual staining method.

RESULTS

D. sephen venom enhances lipid peroxidative markers such as thiobarbituric acid reactive substance, conjugated diene, and lipid hydroperoxide in HeLa cell lines. Stingray venom enhances the ROS levels, which is evidenced by the increased 2-7-diacetyl dichlorofluorescein fluorescence. Further, D. sephen venom treatment altered the mitochondrial membrane potential in HeLa cells. Additionally, we observed increased apoptotic morphological changes in D. sephen venom-treated groups.

CONCLUSIONS

Dasyatis sephen venom exhibits potent antiproliferative effect on HeLa cell line and upon further purification it could be a promising antiproliferative agent.

Structural characterization of a novel peptide with antimicrobial activity from the venom gland of the scorpion Tityus stigmurus: Stigmurin

A new antimicrobial peptide, herein named Stigmurin, was selected based on a transcriptomic analysis of the Brazilian yellow scorpion Tityus stigmurus venom gland, an underexplored source for toxic peptides with possible biotechnological applications. Stigmurin was investigated in silico, by circular dichroism (CD) spectroscopy, and in vitro. The CD spectra suggested that this peptide interacts with membranes, changing its conformation in the presence of an amphipathic environment, with predominance of random coil and beta-sheet structures. Stigmurin exhibited antibacterial and antifungal activity, with minimal inhibitory concentrations ranging from 8.7 to 69.5μM. It was also showed that Stigmurin is toxic against SiHa and Vero E6 cell lines. The results suggest that Stigmurin can be considered a potential anti-infective drug.

Chlorotoxin: a helpful natural scorpion peptide to diagnose glioma and fight tumor invasion

Chlorotoxin is a small 36 amino-acid peptide identified from the venom of the scorpion Leiurus quinquestriatus. Initially, chlorotoxin was used as a pharmacological tool to characterize chloride channels. While studying glioma-specific chloride currents, it was soon discovered that chlorotoxin possesses targeting properties towards cancer cells including glioma, melanoma, small cell lung carcinoma, neuroblastoma and medulloblastoma. The investigation of the mechanism of action of chlorotoxin has been challenging because its cell surface receptor target remains under questioning since two other receptors have been claimed besides chloride channels. Efforts on chlorotoxin-based applications focused on producing analogues helpful for glioma diagnosis, imaging and treatment. These efforts are welcome since gliomas are very aggressive brain cancers, close to impossible to cure with the current therapeutic arsenal. Among all the chlorotoxin-based strategies, the most promising one to enhance patient mean survival time appears to be the use of chlorotoxin as a targeting agent for the delivery of anti-tumor agents. Finally, the discovery of chlorotoxin has led to the screening of other scorpion venoms to identify chlorotoxin-like peptides. So far several new candidates have been identified. Only detailed research and clinical investigations will tell us if they share the same anti-tumor potential as chlorotoxin.

Big Potassium (BK) ion channels in biology, disease and possible targets for cancer immunotherapy

The Big Potassium (BK) ion channel is commonly known by a variety of names (Maxi-K, KCNMA1, slo, stretch-activated potassium channel, KCa1.1). Each name reflects a different physical property displayed by this single ion channel. This transmembrane channel is found on nearly every cell type of the body and has its own distinctive roles for that tissue type. The BKα channel contains the pore that releases potassium ions from intracellular stores. This ion channel is found on the cell membrane, endoplasmic reticulum, Golgi and mitochondria. Complex splicing pathways produce different isoforms. The BKα channels can be phosphorylated, palmitoylated and myristylated. BK is composed of a homo-tetramer that interacts with β and γ chains. These accessory proteins provide a further modulating effect on the functions of BKα channels. BK channels play important roles in cell division and migration. In this review, we will focus on the biology of the BK channel, especially its role, and its immune response towards cancer. Recent proteomic studies have linked BK channels with various proteins. Some of these interactions offer further insight into the role that BK channels have with cancers, especially with brain tumors. This review shows that BK channels have a complex interplay with intracellular components of cancer cells and still have plenty of secrets to be discovered.

Expression of neonatal Nav1.5 in human brain astrocytoma and its effect on proliferation, invasion and apoptosis of astrocytoma cells

In the present study, we designed and conducted a series of assays to determine the expression of voltage-gated sodium channel (VGSC) neonatal isoform Nav1.5 (nNav1.5) in human brain astrocytoma and its effect on the proliferation, migration, invasion and apoptosis of astrocytoma U251 cells. The results showed that nNav1.5 mRNA and protein were expressed in both human brain astrocytoma and normal brain tissues, but their expression levels in astrocytoma were significantly higher (P<0.05). In astrocytomas, nNav1.5 mRNA and protein levels were also different (P<0.05) and were correlated with pathological grades. The immunofluorescence confocal microscopy observations demonstrated that nNav1.5 protein was expressed in the nucleus, cytoplasm and membrane of the astrocytoma cells. After transfection, the small interfering RNA (siRNA) targeted to nNav1.5 significantly reduced the expression levels of SCN5A/nNav1.5 mRNA and protein by 57.2% (P<0.05) and 66.6% (P<0.05), respectively. The MTT, wound healing, Matrigel invasion and flow cytometric assays confirmed that following siRNA downregulation of the expression of the SCN5A/nNav1.5 gene, the in vitro proliferation and in vitro invasiveness of the U251 cells were significantly reduced (P<0.05 for both comparisons), and the apoptosis rate was significantly increased (P<0.05). These results revealed that nNav1.5 expression in human brain astrocytoma was upregulated, and its expression was positively correlated with the degree of malignancy. Additionally, reduced nNav1.5 expression significantly suppressed the proliferation and invasiveness of astrocytoma cells, indicating a new target in the molecular diagnosis and therapy of astrocytoma.

Scorpion venoms as a potential source of novel cancer therapeutic compounds

Scorpions and their venoms have been used in traditional medicine for thousands of years in China, India and Africa. The scorpion venom is a highly complex mixture of salts, nucleotides, biogenic amines, enzymes, mucoproteins, as well as peptides and proteins (e.g. neurotoxins). One of the recently observed biological properties of animal venoms and toxins is that they possess anticancer potential. An increasing number of studies have shown that scorpion venoms and toxins can decrease cancer growth, induce apoptosis and inhibit cancer progression and metastasis in vitro and in vivo. Several active molecules with anticancer activities, ranging from inhibition of proliferation and cell cycle arrest to induction of apoptosis and decreasing cell migration and invasion, have been isolated from scorpion venoms. These observations have shed light on the application of scorpion venoms and toxins as potential novel cancer therapeutics. This mini-review focuses on the anticancer potential of scorpion venoms and toxins and the possible mechanisms for their antitumor activities.

Resistance of cervical adenocarcinoma cells (HeLa) to venom from the scorpion Centruroides limpidus limpidus

BACKGROUND

The venom of Centruroides limpidus limpidus (Cll) is a mixture of pharmacologically active principles. The most important of these are toxic proteins that interact both selectively and specifically with different cellular targets such as ion channels. Recently, anticancer properties of the venom from other scorpion species have been described. Studies in vitro have shown that scorpion venom induces cell death, inhibits proliferation and triggers the apoptotic pathway in different cancer cell lines. Herein, after treating human cervical adenocarcinoma (HeLa) cells with Cll crude venom, their cytotoxic activity and apoptosis induction were assessed.

RESULTS

Cll crude venom induced cell death in normal macrophages in a dose-dependent manner. However, through viability assays, HeLa cells showed high survival rates after exposure to Cll venom. Also, Cll venom did not induce apoptosis after performing ethidium bromide/acridine orange assays, nor was there any evidence of chromatin condensation or DNA fragmentation.

CONCLUSIONS

Crude Cll venom exposure was not detrimental to HeLa cell cultures. This may be partially attributable to the absence of specific HeLa cell membrane targets for molecules present in the venom of Centruroides limpidus limpidus. Although these results might discourage additional studies exploring the potential of Cll venom to treat human papilloma cervical cancer, further research is required to explore positive effects of crude Cll venom on other cancer cell lines.

Melittin: a lytic peptide with anticancer properties

Melittin (MEL) is a major peptide constituent of bee venom that has been proposed as one of the upcoming possibilities for anticancer therapy. Recent reports point to several mechanisms of MEL cytotoxicity in different types of cancer cells such as cell cycle alterations, effect on proliferation and/or growth inhibition, and induction of apoptotic and necrotic cell death trough several cancer cell death mechanisms, including the activation of caspases and matrix metalloproteinases. Although cytotoxic to a broad spectrum of tumour cells, the peptide is also toxic to normal cells. Therefore its therapeutic potential cannot be achieved without a proper delivery vehicle which could be overcome by MEL nanoparticles that possess the ability to safely deliver significant amount of MEL intravenously, and to target and kill tumours. This review paper summarizes the current knowledge and brings latest research findings on the anticancer potential of this lytic peptide with diverse functions.

Scorpion peptides: potential use for new drug development

Several peptides contained in scorpion fluids showed diverse array of biological activities with high specificities to their targeted sites. Many investigations outlined their potent effects against microbes and showed their potential to modulate various biological mechanisms that are involved in immune, nervous, cardiovascular, and neoplastic diseases. Because of their important structural and functional diversity, it is projected that scorpion-derived peptides could be used to develop new specific drugs. This review summarizes relevant findings improving their use as valuable tools for new drugs development.

pEGFP-N1-mediated BmK CT expression suppresses the migration of glioma

Gliomas can diffuse into the normal brain and this invasion of glioma cells involves modification of receptor-mediated adhesive properties of tumor cells, degradation and remodeling of extracellular matrix by tumor-secreted metalloproteinase (MMPs) such as MMP-2, consequently creating an intercellular space for invasion of glioma cells. BmK CT, one of the key toxins in scorpion Buthus martensii Karsch venom, is a novel blocker of the chloride ion channel and MMP-2. In this report, a recombinant plasmid pEGFP-N1-BmK CT was constructed and characterized by in vitro studies. The results showed that pEGFP-N1 mediated BmK CT expression displayed a high activity in suppressing cell migration via MMP-2. The potential therapeutic effect of pEGFP-N1 mediated BmK CT against rat glioma C6 cells was assessed and its potential mechanism was elucidated. It represented an approach for developing a novel therapeutic agent-recombinant plasmid pEGFP-N1-BmK CT as an efficient and powerful adjuvant.

Scorpion venom component III inhibits cell proliferation by modulating NF-κB activation in human leukemia cells

Scorpion venom contains various groups of compounds that exhibit anticancer activity against a variety of malignancies through a poorly understood mechanism. While the aberrant activation of nuclear factor κB (NF-κB) has been linked with hematopoietic malignancies, we hypothesized that scorpion venom mediates its effects by modulating the NF-κB signaling pathway. In the present study, we examined the effects of scorpion venom component III (SVCIII) on the human leukemia cell lines THP-1 and Jurkat and focused on the NF-κB signaling pathway. Our results showed that SVCIII inhibited cell proliferation, caused cell cycle arrest at G1 phase and inhibited the expression of cell cycle regulatory protein cyclin D1 in a dose-dependent manner in THP-1 and Jurkat cells. SVCIII also suppressed the constitutive NF-κB activation through inhibition of the phosphorylation and degradation of IκBα. NF-κB luciferase reporter activity was also inhibited by SVCIII. Our data suggest that SVCIII, a natural compound, may exert its antiproliferative effects by inhibiting the activation of NF-κB and, thus, has potential use in the treatment of hematopoietic malignancies, alone or in combination with other agents.

Scorpion (Odontobuthus doriae) venom induces apoptosis and inhibits DNA synthesis in human neuroblastoma cells

Scorpion and its organs have been used to cure epilepsy, rheumatism, and male impotency since medieval times. Scorpion venom which contains different compounds like enzyme and non-enzyme proteins, ions, free amino acids, and other organic inorganic substances have been reported to posses antiproliferative, cytotoxic, apoptogenic, and immunosuppressive properties. We for the first time report the apoptotic and antiproliferative effects of scorpion venom (Odontobuthus doriae) in human neuroblastoma cells. After exposure of cells to medium containing varying concentrations of venom (10, 25, 50, 100, and 200 μg/ml), cell viability decreased to 90.75, 75.53, 55.52, 37.85, and 14.30%, respectively, after 24 h. Cells expressed morphological changes like swelling, inhibition of neurite outgrowth, irregular shape, aggregation, rupture of membrane, and release of cytosolic contents after treatment with venom. Lactate dehydrogenase (LDH) level increased in 50 and 100 μg/ml as compared to control, but there was no significant increase in LDH level at a dose of 10 and 20 μg/ml. Two concentrations viz. 50 and 100 μ/ml were selected because of the profound effect of these concentrations on the cellular health and population. Treatment with these two concentrations induced reactive nitrogen intermediates and depolarization in mitochondria. While caspase-3 activity increased in a concentration-dependent manner, only 50 μg/ml was able to fragment DNA. It was interesting to note that at higher dose, i.e., 100 μg/ml, the cells were killed, supposedly by acute necrosis. DNA synthesis evidenced by bromodeoxyuridine (BrdU) incorporation was inhibited in a concentration-dependent manner. The cells without treatment incorporated BrdU with high affinity confirming their cancerous nature whereas very less incorporation was noticed in treated cells. Our results show apoptotic and antiproliferative potential of scorpion venom (O. doriae) in human neuroblastoma cells. These properties make scorpion venom a valuable therapeutic agent in cancer research.

Purification, synthesis and characterization of AaCtx, the first chlorotoxin-like peptide from Androctonus australis scorpion venom

AaCtx is the first chlorotoxin-like peptide isolated from Androctonus australis scorpion venom. Its amino acid sequence shares 70% similarity with chlorotoxin from Leiurus quinquestriatus scorpion venom, from which it differs by twelve amino acids. Due to its very low concentration in venom (0.05%), AaCtx was chemically synthesized. Both native and synthetic AaCtx were active on invasion and migration of human glioma cells. However, their activity was found to be lower than that of chlorotoxin. The molecular model of AaCtx shows that most of amino acids differing between AaCtx and chlorotoxin are localized on the N-terminal loop and the α-helix. Based on known compounds that block chloride channels, we suggest that the absence of negative charged amino acids on AaCtx structure may be responsible for its weak activity on glioma cells migration and invasion. This finding serves as a starting point for structure-function relationship studies leading to design high specific anti-glioma drugs.

Potential adenovirus-mediated gene therapy of glioma cancer

Malignant gliomas are typically characterized by rapid cell proliferation and a marked propensity to invade and damage surrounding tissues. They are the main brain tumors notoriously resistant to currently available therapies, since they fail to undergo apoptosis upon anticancer treatments. With recent advances in neuroscience and improved understanding of the molecular mechanisms of invasive migration, gene therapy provides a new strategy for treating glioma cancer. Brain tumor gene therapy using viral vectors and stem cells has shown promise in animal model and human patient studies. Here, we review recent studies on engineering adenoviral vectors that can be used as therapy for brain tumors. The new findings presented in this study are essential for the further exploration of this cancer and they represent an approach for developing a newer and more effective therapeutic approach in the clinical treatment of human glioma cancer.

Upregulation of PTEN involved in scorpion venom-induced apoptosis in a lymphoma cell line

We investigated whether the venom of the scorpion Buthus martensii Karsch (BmK) inhibited growth of human lymphoma cells by inducing apoptosis, and studied possible signal pathways involved in this cell death. BmK venom selectively reduced the viability of Raji and Jurkat cells, and had low toxicity to human peripheral blood lymphocytes. Flow cytometry showed that BmK venom-induced apoptosis and G(0)/G(1) cell cycle arrest in Raji and Jurkat cells. In Raji cells, BmK venom upregulated the expression of PTEN accompanied by decreased levels of Akt and Bad phosphorylation. Treatment with BmK venom and LY294002 (an inhibitor of Akt) synergistically enhanced apoptosis. The expression of p27 was increased in both PTEN-positive Raji and PTEN-negative Jurkat cells exposed to BmK venom. The results indicate that key regulators in BmK venom-induced apoptosis are PTEN, acting through downregulation of the PI3K/Akt signal pathway, in Raji cells and p27 in Jurkat cells.

Anti-proliferation Effect of Polypeptide Extracted from Scorpion Venom on Human Prostate Cancer Cells in vitro

BACKGROUND

Prostate cancer is a major cause of cancer-related death in men. Therefore there has been considerable interest to explore neoadjuvant therapy. Polypeptide extracted from scorpion venom (PESV), originally obtained from the East-Asian scorpion Buthus martensi Karsch (BmK), is being studied for both prevention and treatment of various human malignancies including prostate cancer.

METHODS

The present study was to investigate the effect of PESV on cell proliferation, cell cycle, and apoptosis in human androgen-independent prostate cancer cells DU-145 in vitro.

RESULTS

PESV treatment on these cells resulted in a significantly dose-dependent growth inhibition with a G1 phase arrest at 40μg/mL after 48h treatment. PESV treatment strongly induced expression of p27 (Kip1), but resulted in a decrease in cyclin E, one of cyclins involved in G1 progression. In other studies, PESV treatment also induced high apoptosis index (AI), confirmed by TdTmediated dUTP-biotin nick-end labeling (TUNEL) assay. Further, the apoptosis induction by PESV (40μg/mL) in DU145 cells was associated with an increase of pro-apoptotic protein Bax.

CONCLUSIONS

These results suggest that PESV modulates the expression of cell cycle-related and apoptosis-related proteins and induces growth inhibition and apoptosis of DU145 cells, providing a strong rationale for future studies to evaluate prevention or/and intervention strategies for PESV in pre-clinical prostate cancer models.

KEYWORDS

Prostate cancer, PESV, cell proliferation, cell cycle, apoptosis.

Amiloride-sensitive Na+ channels contribute to regulatory volume increases in human glioma cells

Despite intensive research, brain tumors remain among the most difficult type of malignancies to treat, due largely to their diffusely invasive nature and the associated difficulty of adequate surgical resection. To migrate through the brain parenchyma and to proliferate, glioma cells must be capable of significant changes in shape and volume. We have previously reported that glioma cells express an amiloride- and psalmotoxin-sensitive cation conductance that is not found in normal human astrocytes. In the present study, we investigated the potential role of this ion channel to mediate regulatory volume increase in glioma cells. We found that the ability of the cells to volume regulate subsequent to cell shrinkage by hyperosmolar solutions was abolished by both amiloride and psalmotoxin 1. This toxin is thought to be a specific peptide inhibitor of acid-sensing ion channel (ASIC1), a member of the Deg/ENaC superfamily of cation channels. We have previously shown this toxin to be an effective blocker of the glioma cation conductance. Our data suggest that one potential role for this conductance may be to restore cell volume during the cell's progression thorough the cell cycle and while the tumor cell migrates within the interstices of the brain.

Potential biochemical therapy of glioma cancer

Glioma is a highly invasive, rapidly spreading form of brain cancer that is resistant to surgical and medical treatment. The recent progresses made in intracellular and ion channels of glioma cells provide a potential new approach for biochemical therapy of brain tumor. In this paper, we reviewed clinical data on chemotherapy by temozolomide and results from new studies on voltage-gated potassium channels, large-conductance Ca(2+)-activated K(+) channels, volume-activated chloride channels, glioma-specific chloride channel and their modulators. These new findings may represent future directions for brain tumor studies and treatment.