Proteomic and functional analyses of the venom of Porthidium lansbergii lansbergii (Lansberg's hognose viper) from the Atlantic Department of Colombia

Toxinological profile and histopathological alterations induced by Bothrocophias campbelli venom from Colombia

Snakebite envenomings most frequently reported in Colombia are caused by snakes of the genera Bothrops, Bothriechis, Bothrocophias, and Porthidium. Their venoms induce local and systemic pathophysiological effects, sometimes leading to permanent sequelae such as reduced mobility of the limbs, amputations, besides the risk of death. The genus Bothrocophias includes nine species, among which B. campbelli has a distribution restricted to the department of Nariño in Colombia. In this work we determined the toxinological profile its venom, by performing assays for the lethal, hemorrhagic, edematogenic, and myotoxic activities in mouse models, as well as for in vitro coagulant activity on human plasma. The lethal toxicity of the venom was 142.7 µg venom/mouse (111.4-179.8 µg/mouse; 6.6-10.6 µg/g body weight) by intraperitoneal route. Its hemorrhagic activity (minimum hemorrhagic dose: 12.7 ± 2.3 µg) is generally weaker compared to other South American vipers, but edematogenic (minimum edematogenic dose 1.0 ± 0.3 µg), and myotoxic (minimum myotoxic dose 3.9 ± 2.5 µg) activities are very potent. Histopathological examination of the injected mouse gastrocnemius muscle showed prominent disorganization of the myofibrils, myonecrosis, and an intense inflammatory leukocyte infiltrate. In vitro, the minimal coagulant dose was 12.3 ± 0.5 µg. Overall, this toxinological profile would predict that the clinical picture of envenomings by B. campbelli might be characterized by moderate disturbances in the coagulation cascade, mild local hemorrhage, and, conversely, severe myonecrosis and edema, which could potentially lead to compartment syndrome and gangrene.

Exploring the Safety of Pllans-II and Antitumoral Potential of Its Recombinant Isoform in Cervical Cancer Therapy

The antitumor potential of proteins from snake venoms has been studied in recent decades, and evidence has emerged that phospholipases A2 can selectively attack cells of various types of tumors. Previous results have shown that phospholipase A2 "Pllans-II," isolated from Porthidium lansbergii lansbergii snake venom, displayed antitumoral activity on cervical cancer and did not alter the viability of non-tumorigenic cells. However, until now, there was no evidence of its safety at the local and systemic levels, nor had experiments been developed to demonstrate that its production using recombinant technology allows us to obtain a molecule with effects similar to those generated by native phospholipase. Thus, we evaluated the impact caused by Pllans-II on murine biomodels, determining whether it induced local hemorrhage or increased pro-inflammatory and liver damage markers and histological alterations in the liver and kidneys. Additionally, the protein was produced using recombinant technology using a pET28a expression vector and the BL21 (DE3) Escherichia coli strain. Equally, its enzymatic activity and anticancer effect were evaluated on cervical cancer lines such as HeLa and Ca Ski. The results demonstrated that Pllans-II did not generate hemorrhagic activity, nor did it increase the pro-inflammatory cytokines IL-6, IL-1B, or TNF-α at doses of 3.28, 1.64, and 0.82 mg/kg. There was also no evidence of organ damage, and only ALT and AST increased in mild levels at the two highest concentrations. Additionally, the recombinant version of Pllans-II showed conservation in its catalytic activity and the ability to generate death in HeLa and Ca Ski cells (42% and 23%, respectively). These results demonstrate the innocuity of Pllans-II at the lowest dose and constitute an advance in considering a molecule produced using recombinant technology a drug candidate for selective attacks against cervical cancer.

Knowledge about Snake Venoms and Toxins from Colombia: A Systematic Review

Colombia encompasses three mountain ranges that divide the country into five natural regions: Andes, Pacific, Caribbean, Amazon, and Orinoquia. These regions offer an impressive range of climates, altitudes, and landscapes, which lead to a high snake biodiversity. Of the almost 300 snake species reported in Colombia, nearly 50 are categorized as venomous. This high diversity of species contrasts with the small number of studies to characterize their venom compositions and natural history in the different ecoregions. This work reviews the available information about the venom composition, isolated toxins, and potential applications of snake species found in Colombia. Data compilation was conducted according to the PRISMA guidelines, and the systematic literature search was carried out in Pubmed/MEDLINE. Venom proteomes from nine Viperidae and three Elapidae species have been described using quantitative analytical strategies. In addition, venoms of three Colubridae species have been studied. Bioactivities reported for some of the venoms or isolated components-such as antibacterial, cytotoxicity on tumoral cell lines, and antiplasmodial properties-may be of interest to develop potential applications. Overall, this review indicates that, despite recent progress in the characterization of venoms from several Colombian snakes, it is necessary to perform further studies on the many species whose venoms remain essentially unexplored, especially those of the poorly known genus Micrurus.

Comparative Analysis of Alpha-1 Orthosteric-Site Binding by a Clade of Central American Pit Vipers (Genera Atropoides, Cerrophidion, Metlapilcoatlus, and Porthidium)

The distribution and relative potency of post-synaptic neurotoxic activity within Crotalinae venoms has been the subject of less investigation in comparison with Elapidae snake venoms. No previous studies have investigated post-synaptic neurotoxic activity within the Atropoides, Metlapilcoatlus, Cerrophidion, and Porthidium clade. Given the specificity of neurotoxins to relevant prey types, we aimed to uncover any activity present within this clade of snakes that may have been overlooked due to lower potency upon humans and thus not appearing as a clinical feature. Using biolayer interferometry, we assessed the relative binding of crude venoms to amphibian, lizard, bird, rodent and human α-1 nAChR orthosteric sites. We report potent alpha-1 orthosteric site binding in venoms from Atropoides picadoi, Metlapilcoatlus occiduus, M. olmec, M. mexicanus, M. nummifer. Lower levels of binding, but still notable, were evident for Cerrophidion godmani, C. tzotzilorum and C. wilsoni venoms. No activity was observed for Porthidium venoms, which is consistent with significant alpha-1 orthosteric site neurotoxicity being a trait that was amplified in the last common ancestor of Atropoides/Cerrophidion/Metlapilcoatlus subsequent to the split by Porthidium. We also observed potent taxon-selective activity, with strong selection for non-mammalian targets (amphibian, lizard, and bird). As these are poorly studied snakes, much of what is known about them is from clinical reports. The lack of affinity towards mammalian targets may explain the knowledge gap in neurotoxic activity within these species, since symptoms would not appear in bite reports. This study reports novel venom activity, which was previously unreported, indicating toxins that bind to post-synaptic receptors may be more widespread in pit vipers than previously considered. While these effects appear to not be clinically significant due to lineage-specific effects, they are of significant evolutionary novelty and of biodiscovery interest. This work sets the stage for future research directions, such as the use of in vitro and in vivo models to determine whether the alpha-1 orthosteric site binding observed within this study confers neurotoxic venom activity.

Proteomic and functional analyses of Lachesis acrochorda snake venom from the Valle del Cauca Department of Colombia

Lachesis acrochorda envenomation has a lethality rate of approximately 90%. Despite its high lethality, little is known about its local and systemic effects and its relationship with its protein content. Thus, to increase knowledge of L. acrochorda snake venom from the Southwestern ecoregion of Colombia, we developed a proteomic analysis using a "bottom-up shotgun proteomic profiling" approach. Besides, we evaluated toxinological properties and compared the effects with the Bothrops asper snake venom activities. The RP-HPLC profile showed similarities with the L. acrochorda snake venom from the Northwestern ecoregion of Colombia. However, the results displayed differences in the protein families identified, probably due to the proteomic identification strategy. The in vitro and in vivo tests showed a L. acrochorda snake venom with Phospholipase A₂ and metalloproteinase activities related to myotoxic, edematic, and hemorrhagic effects. Nevertheless, the L. acrochorda snake venom displayed a low lethality despite a large amount of inoculated venom. This investigation's results will help us improve the knowledge about the relationship between the clinical manifestations of L. acrochorda envenomation and the venom protein content.

Pllans-II Induces Cell Death in Cervical Cancer Squamous Epithelial Cells via Unfolded Protein Accumulation and Endoplasmic Reticulum Stress

Due to the lack of chemotherapeutic drugs that selectively affect cervical cancer cells, natural sources such as snake venom are currently being investigated for molecules with antitumor potential. Pllans–II, a phospholipase A₂ type–Asp49 from Porthidium lansbergii lansbergii snake venom, induced cell death in a cervical cancer cell line—Ca Ski—related to dysfunction in the ability to resolve endoplasmic reticulum stress, evidenced by sub–expression of genes such as PERK, ERO1 PDIs, HSP70, and CHOP. Western blot analysis validated the last two genes′ sub–expression at the protein level. In addition, Pllans–II presented a dose–dependent cytotoxic effect on cancer cells and an insignificant effect on healthy endothelial cells (HUVEC). Additionally, Pllans–II inhibited cancer cells′ adhesion and migration capacity, induced cell cycle arrest in the G2/M phase, and induced apoptosis stimulated possibly by the extrinsic route. These results demonstrate for the first time that Pllans–II has an antitumor effect on a squamous epithelial cervical cancer cell line and represents a possible biotechnological tool for designing a prominent antitumor agent.

Bibliometric Analysis of Literature in Snake Venom-Related Research Worldwide (1933-2022)

Snake envenomation is a severe economic and health concern affecting countries worldwide. Snake venom carries a wide variety of small peptides and proteins with various immunological and pharmacological properties. A few key research areas related to snake venom, including its applications in treating cancer and eradicating antibiotic-resistant bacteria, have been gaining significant attention in recent years. The goal of the current study was to analyze the global profile of literature in snake venom research. This study presents a bibliometric review of snake venom-related research documents indexed in the Scopus database between 1933 and 2022. The overall number of documents published on a global scale was 2999, with an average annual production of 34 documents. Brazil produced the highest number of documents (n = 729), followed by the United States (n = 548), Australia (n = 240), and Costa Rica (n = 235). Since 1963, the number of publications has been steadily increasing globally. At a worldwide level, antivenom, proteomics, and transcriptomics are growing hot issues for research in this field. The current research provides a unique overview of snake venom research at global level from 1933 through 2022, and it may be beneficial in guiding future research.

Differential Antivenom and Small-Molecule Inhibition of Novel Coagulotoxic Variations in Atropoides, Cerrophidion, Metlapilcoatlus, and Porthidium American Viperid Snake Venoms

Within Neotropical pit-vipers, the Mexican/Central-American clade consisting of Atropoides, Cerrophidion, Metlapilcoatlus, and Porthidium is a wide-ranging, morphologically and ecologically diverse group of snakes. Despite their prevalence, little is known of the functional aspects of their venoms. This study aimed to fill the knowledge gap regarding coagulotoxic effects and to examine the potential of different therapeutic approaches. As a general trait, the venoms were shown to be anticoagulant but were underpinned by diverse biochemical actions. Pseudo-procoagulant activity (i.e., thrombin-like), characterized by the direct cleavage of fibrinogen to form weak fibrin clots, was evident for Atropoides picadoi, Cerrophidiontzotzilorum, Metlapilcoatlus mexicanus, M. nummifer, M. occiduus, M. olmec, and Porthidium porrasi. In contrast, other venoms cleaved fibrinogen in a destructive (non-clotting) manner, with C. godmani and C. wilsoni being the most potent. In addition to actions on fibrinogen, clotting enzymes were also inhibited. FXa was only weakly inhibited by most species, but Cerrophidion godmani and C. wilsoni were extremely strong in their inhibitory action. Other clotting enzymes were more widely inhibited by diverse species spanning the full taxonomical range, but in each case, there were species that had these traits notably amplified relatively to the others. C. godmani and C. wilsoni were the most potent amongst those that inhibited the formation of the prothrombinase complex and were also amongst the most potent inhibitors of Factor XIa. While most species displayed only low levels of thrombin inhibition, Porthidium dunni potently inhibited this clotting factor. The regional polyvalent antivenom produced by Instituto Picado Clodomiro was tested and was shown to be effective against the diverse anticoagulant pathophysiological effects. In contrast to the anticoagulant activities of the other species, Porthidium volcanicum was uniquely procoagulant through the activation of Factor VII and Factor XII. This viperid species is the first snake outside of the Oxyuranus/Pseudonaja elapid snake clade to be shown to activate FVII and the first snake venom of any kind to activate FXII. Interestingly, while small-molecule metalloprotease inhibitors prinomastat and marimastat demonstrated the ability to prevent the procoagulant toxicity of P. volcanicum, neither ICP antivenom nor inhibitor DMPS showed this effect. The extreme variation among the snakes here studied underscores how venom is a dynamic trait and how this can shape clinical outcomes and influence evolving treatment strategies.

First functional and proteomic analysis of Bothrops asper snake venom from Gorgona Island - Colombia, and its comparative characterization with two Colombian Southwest ecoregions

Bothrops asper envenoming is a public health problem in tropical regions of Latin America. Bothrops asper has spread until Gorgona Island in the Pacific Colombian Ocean, but its biochemical venom characterization is poorly known. Thus, to increase knowledge on Bothrops species venoms, we developed for the first time the proteomic analysis using a shotgun approach and performed functional evaluations relevant to its toxicity and compared with two Colombian Southwest ecoregions from the Pacific and Western sides. Besides, we evaluated two antivenoms produced in Colombia (INS and PROBIOL) against three B. asper venom ecoregions through the ELISA approach and first-generation antivenom against B. asper from Gorgona Island. The protein components of B. asper from Gorgona Island were assigned to nine known protein families, sharing a conserved compositional pattern with B. asper from the pacific ecoregion. The RP-HPLC and in vitro activity suggest a phenotypic congruence in the expression of PLA₂s and metalloproteinases between the B. asper snake venom from Gorgona Island and pacific, but inversely to the Western ecoregion. Additionally, the antivenoms immunoreactivity against the three B. asper lineage venoms was different. The INS displayed higher titers than PROBIOL against all the venoms and exhibited the most effective immunocapturing capacity against the individual components of snake venom from Gorgona Island. The results of this investigation suggest that B. asper from Gorgona Island displayed similar clinical manifestations concerning the Pacific ecoregion, and the immunoreactivity by antivenoms could be used after B. asper envenomation in Gorgona Island, using one of them preferably.

Venom proteomic analysis of medically important Nigerian viper Echis ocellatus and Bitis arietans snake species

Snakebite envenoming remains a neglected tropical disease which poses severe health hazard, especially for the rural inhabitants in Africa. In Nigeria, vipers are responsible for the highest number of deaths. Hydrophilic interaction liquid chromatography coupled with LC-MS/MS was used to analyze the crude venoms of Echis ocellatus (Carpet viper) and Bitis arietans (Puff adder) in order to understand their venom proteomic identities. Results obtained revealed that gel-free proteomic analysis of the crude venoms led to the identification of 85 and 79 proteins, respectively. Seventy-eight (78) proteins were common between the two snake species with a 91.8% similarity score. The identified proteins belong to 18 protein families in E. ocellatus and 14 protein families in B. arietans. Serine proteases (22.31%) and metalloproteinases (21.06%) were the dominant proteins in the venom of B. arietans; while metalloproteinases (34.84%), phospholipase A₂s (21.19%) and serine proteases (15.50%) represent the major toxins in the E. ocellatus venom. Other protein families such as three-finger toxins and cysteine-rich venom proteins were detected in low proportions. This study provides an insight into the venom proteomic analysis of the two Nigerian viper species, which could be useful in identifying the toxin families to be neutralized in case of envenomation.

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Venom proteomic of Nigeria's most medically important snakes is presented.

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SVMP, SVSP and PLA₂ were the major toxin families in E. ocellatus and B. arietans.

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The venom proteomes of these vipers displayed 91.8% similarity in composition.

Venomics of the poorly studied hognosed pitvipers Porthidium arcosae and Porthidium volcanicum

We report the first proteomics analyses of the venoms of two poorly studied snakes, the Manabi hognosed pitviper Porthidium arcosae endemic to the western coastal province of Manabí (Ecuador), and the Costa Rican hognosed pitviper P. volcanicum with distribution restricted to South Pacific Costa Rica and western Panamá. These venom proteomes share a conserved compositional pattern reported in four other congeneric species within the clade of South American Porthidium species, P. nasutum, P. lansbergii, P. ophryomegas, and P. porrasi. The paraspecific immunorecognition profile of antivenoms produced in Costa Rica (ICP polyvalent), Perú (Instituto Nacional de Salud) and Brazil (soro antibotrópico pentavalente, SAB, from Instituto Butantan) against the venom of P. arcosae was investigated through a third-generation antivenomics approach. The maximal venom-binding capacities of the investigated antivenoms were 97.1 mg, 21.8 mg, and 25.7 mg of P. arcosae venom proteins per gram of SAB, ICP, and INS-PERU antibody molecules, respectively, which translate into 28.4 mg, 13.1 mg, and 15.2 mg of total venom proteins bound per vial of SAB, ICP, and INS-PERU AV. The antivenomics results suggest that 21.8%, 7.8% and 6.1% of the SAB, ICP, and INS-PERU antibody molecules recognized P. arcosae venom toxins. The SAB antivenom neutralized P. arcosae venom's lethality in mice with an ED₅₀ of 31.3 mgV/g SAB AV. This preclinical neutralization paraspecificity points to Brazilian SAB as a promising candidate for the treatment of envenomings by Ecuadorian P. arcosae. BIOLOGICAL SIGNIFICANCE: Assessing the preclinical efficacy profile of antivenoms against homologous and heterologous medically relevant snake venoms represents an important goal towards defining the biogeographic range of their clinical utility. This is particularly relevant in regions, such as Mesoamerica, where a small number of pharmaceutical companies produce antivenoms against the venoms of a small number of species of maximum medical relevance among the local rich herpetofauna, leaving a wide range of snakes of secondary medical relevance, but also causing life-threatening human envenomings without nominal clinical coverage. This work is part of a larger project aiming at mapping the immunological characteristics of antivenoms generated in Latin American countries towards venoms of such poorly studied snakes of the local and neighboring countries' herpetofauna. Here we report the proteomics characterization of the Manabi hognosed pitviper Porthidium arcosae endemic to the western coastal province of Manabí (Ecuador), and the Costa Rican hognosed pitviper P. volcanicum with distribution restricted to southwestern Costa Rica, the antivenomics assessment of three bothropoid commercial antivenoms produced in Costa Rica, Perú, and Brazil against the venom components of P. arcosae, and the in vivo capacity of the Brazilian soro antibotrópico pentavalente (SAB) from Instituto Butantan to neutralize the murine lethality of P. arcosae venom. The preclinical paraspecific ED₅₀ of 31.3 mg of P. arcosae venom per gram of antivenom points to Brazilian SAB as a promising candidate for the treatment of envenomings by the Manabi hognosed pitviper P. arcosae.

Evaluation of the systemic alterations triggers by Porthidium lansbergii lansbergii snake venom

The systemic effects generated by Porthidium lansbergii lansbergii envenoming, a species found in the northern region of Colombia, is poorly known. The present study aimed to analyze for the first time the mice's behavior, the histological alterations, and changes in biochemical markers levels resulting from the intraperitoneal injection of an LD₅₀ of P. lansbergii lansbergii snake venom on mice. The envenoming mice displayed hypodynamic condition, clonic head movements, accompanied by bradypnea and thoracoabdominal imbalance. After 7 h of envenoming, the mice showed an ecchymotic region at the injection site, including bleeding in the pleural, liver, and kidney capsules. The effect on the brain revealed a micro-hemorrhage in the sensorimotor cortex with substantial loss of neurons. The venom caused dilated blood vessels in lung tissue, with endothelial necrosis associated with alveolar rupture. The liver showed parenchyma alteration with many extravasated erythrocytes. The kidneys exhibited renal tubules necrosis and a statistically significant increase in creatinine concentration. ALP and ALT's enzymatic activities remained constant at 7 h after envenoming but increased at 12 h. AST and LDH were significantly increased at 7 h but decreased to the near baseline 12 h after venom administration. Massive hemorrhages could trigger a hypovolemic shock, which could lead to death after several h without treatment. Knowledge of P. lansbergii lansbergii snake bites' injuries is essential to make the appropriate diagnostic in human envenoming cases by this snake.

Snake venom vascular endothelial growth factors (svVEGFs): Unravelling their molecular structure, functions, and research potential

Vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis, a physiological process characterized by the formation of new vessels from a preexisting endothelium. VEGF has also been implicated in pathologic states, such as neoplasias, intraocular neovascular disorders, among other conditions. VEGFs are distributed in seven different families: VEGF-A, B, C, D, and PIGF (placental growth factor), which are identified in mammals; VEGF-E, which are encountered in viruses; and VEGF-F or svVEGF (snake venom VEGF) described in snake venoms. This is the pioneer review of svVEGF family, exploring its distribution among the snake venoms, molecular structure, main functions, and potential applications.

The Sequence and Three-Dimensional Structure Characterization of Snake Venom Phospholipases B

Snake venom phospholipases B (SVPLBs) are the least studied enzymes. They constitute about 1% of Bothrops crude venoms, however, in other snake venoms, it is present in less than 1%. These enzymes are considered the most potent hemolytic agent in the venom. Currently, no structural information is available about these enzymes from snake venom. To better understand its three-dimensional structure and mechanisms of envenomation, the current work describes the first model-based structure report of this enzyme from Bothrops moojeni venom named as B. moojeni phospholipase B (PLB_Bm). The structure model of PLB_Bm was generated using model building software like I-TESSER, MODELLER 9v19, and Swiss-Model. The build PLB_Bm model was validated using validation tools (PROCHECK, ERRAT, and Verif3D). The analysis of the PLB_Bm modeled structure indicates that it contains 491 amino acid residues that form a well-defined four-layer αββα sandwich core and has a typical fold of the N-terminal nucleophile aminohydrolase (Ntn-hydrolase). The overall structure of PLB_Bm contains 18 β-strands and 17 α-helices with many connecting loops. The structure divides into two chains (A and B) after maturation. The A chain is smaller and contains 207 amino acid residues, whereas the B chain is larger and contains 266 amino acid residues. The sequence and structural comparison among homologous snake venom, bacterial, and mammals PLBs indicate that differences in the length and sequence composition may confer variable substrate specificity to these enzymes. Moreover, the surface charge distribution, average volume, and depth of the active site cavity also vary in these enzymes. The present work will provide more information about the structure-function relationship and mechanism of action of these enzymes in snakebite envenomation.

Comparative characterization of Viperidae snake venoms from Perú reveals two compositional patterns of phospholipase A2 expression

Snake species within the Bothrops complex (sensu lato) are of medical relevance in Latin America, but knowledge on their venom characteristics is limited, or even unavailable, for some taxa. Perú harbors 17 species of pit vipers, within the genera Bothrops, Bothriechis, Bothrocophias, Porthidium, Crotalus, and Lachesis. This study compared the venoms of twelve species, through chromatographic and electrophoretic profiles, as well as proteolytic and phospholipase A₂ (PLA₂) activities. Also, proteomic profiles were analyzed for nine of the venoms using a shotgun approach. Results unveiled conspicuous differences in the expression of venom PLA₂s among species, six of them presenting scarce levels as judged by RP-HPLC profiles. Since most species within the bothropoid lineage possess venoms with high to intermediate abundances of this protein family, our findings suggest the existence of a phenotypic duality in the expression of venom PLA₂s within the Bothrops (sensu lato) complex. Bothrops barnetti and Bothrocophias andianus venoms, very scarce in PLA₂s, were shown to lack significant myotoxic activity, highlighting that the observed variability in PLA₂ expression bears toxicological correlations with effects attributed to these proteins. Finally, an attempt to identify phylogenetic relationships of bothropoid species from Perú presenting low- or high-PLA₂ venom phenotypes showed an interspersed pattern, thus precluding a simple phylogenetic interpretation of this venom compositional dichotomy.

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Venoms from 12 viperids of Perú were compared.

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Conspicuous differences in the expression of PLA₂ were found.

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Venoms presenting scarce levels of PLA₂ lack myotoxicity.

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A new phenotypic dichotomy in venom PLA₂ expression is described within Bothrops (sensu lato).

Putting the brakes on tumorigenesis with snake venom toxins: New molecular insights for cancer drug discovery

Cancer cells exhibit molecular characteristics that confer them different proliferative capacities and survival advantages to adapt to stress conditions, such as deregulation of cellular bioenergetics, genomic instability, ability to promote angiogenesis, invasion, cell dormancy, immune evasion, and cell death resistance. In addition to these hallmarks of cancer, the current cytostatic drugs target the proliferation of malignant cells, being ineffective in metastatic disease. These aspects highlight the need to identify promising therapeutic targets for new generations of anti-cancer drugs. Toxins isolated from snake venoms are a natural source of useful molecular scaffolds to obtain agents with a selective effect on cancer cells. In this article, we discuss the recent advances in the molecular mechanisms of nine classes of snake toxins that suppress the hallmarks of cancer by induction of oxidative phosphorylation dysfunction, reactive oxygen species-dependent DNA damage, blockage of extracellular matrix-integrin signaling, disruption of cytoskeleton network and inhibition of growth factor-dependent signaling. The possible therapeutic implications of toxin-based anti-cancer drug development are also highlighted.

Cervical cancer and potential pharmacological treatment with snake venoms

Cervical cancer is the fourth most common cancer worldwide in women. Apoptosis reactivation has become the main strategy for decreasing cancer proliferation. There is a need to extend the search for new drugs to implement more effective and less toxic strategies for cervical cancer treatment. Research has been carried out to find new drugs that have minimal side effects and that focus on the tumor microenvironment, particularly in the induction of cellular apoptosis and cell migration and the inhibition of angiogenesis. Potent toxins from snake venoms have shown potential as sources for the synthesis of new drugs with such characteristics. The present work aimed to describe cervical cancer characteristics, associated risk factors, current treatments and to highlight the effects of toxins isolated from the venom of snakes of the Viperidae family on cervical cancer cell lines.

Antitumoral Potential of Lansbermin-I, a Novel Disintegrin from Porthidium lansbergii lansbergii Venom on Breast Cancer Cells

Background:

Disintegrins from snake venoms bind with high specificity cell surface integrins, which are important pharmacological targets associated with cancer development and progression.

Objective:

In this study, we isolated a disintegrin from the Porthidium lansbergii lansbergii venom and evaluated its antitumoral effects on breast cancer cells.

Methods:

The isolation of the disintegrin was performed on RP-HPLC and the inhibition of platelet aggregation was evaluated on human platelet-rich plasma. The inhibition of cell adhesion was also evaluated in vitro on cultures of cell lines by the MTT method as well as the inhibition of breast cancer cell migration by the wound healing assay. The binding of the disintegrin to integrin subunits was verified by flow cytometry and confocal microscopy. Finally, inhibition of angiogenesis was assessed in vitro on HUVEC cells and the concentration of VEGF was measured in the cellular supernatants.

Results:

The disintegrin, named Lansbermin-I, is a low molecular weight protein (< 10 kDa) that includes an RGD on its sequence identified previously. Lansbermin-I showed potent inhibition of ADP and collagen-induced platelet aggregation on human plasma and also displayed inhibitory effects on the adhesion and migration of breast cancer MCF7 and MDA-MB 231cell lines, without affecting nontumorigenic breast MCF-10A and lung BEAS cells. Additionally, Lansbermin-I prevented MCF7 cells to adhere to fibronectin and collagen, and also inhibited in vitro angiogenesis on human endothelial HUVEC cells.

Conclusion:

Our results display the first report on the antitumor and anti-metastatic effects of an RGDdisintegrin isolated from a Porthidium snake venom by possibly interfering with α2 and/or β1-containing integrins. Thus, Lansbermin-I could be an attractive model to elucidate the role of disintegrins against breast cancer development.

Proteomic profiling, functional characterization, and immunoneutralization of the venom of Porthidium porrasi, a pitviper endemic to Costa Rica

The genus Porthidium includes nine pitviper species inhabiting Mexico, Central America, and northern South America. Porthidium porrasi is a species endemic to the Southwest of Costa Rica, for which no information on its venom was available. In this study, the proteomic composition and functional activities of P. porrasi venom are described. The most abundant venom proteins were identified as metalloproteinases (36.5%). In descending order of abundance, proteins belonging to the disintegrin, phospholipase A₂, serine proteinase, C-type lectin/lectin-like, vascular endothelial growth factor, Cysteine-rich secretory protein, L-amino acid oxidase, phospholipase B, and phosphodiesterase families were also identified. P. porrasi venom showed a weak lethal potency in mice (10 μg/g body weight by intraperitoneal route), induced marked hemorrhage and edema, and weak myotoxic effect. These in vivo activities, as well as those assayed in vitro (proteolytic and phospholipase A₂ activities) correlated with compositional data. A comparison of P. porrasi venom with those of three other Porthidium species studied to date reveals a generally conserved compositional and functional pattern in this pitviper genus. Importantly, the lethal effect of P. porrasi venom in mice was adequately cross-neutralized by a heterospecific polyvalent antivenom, supporting its use in the treatment of eventual envenomings by this species.

Comparative analyses of putative toxin gene homologs from an Old World viper, Daboia russelii

Availability of snake genome sequences has opened up exciting areas of research on comparative genomics and gene diversity. One of the challenges in studying snake genomes is the acquisition of biological material from live animals, especially from the venomous ones, making the process cumbersome and time-consuming. Here, we report comparative sequence analyses of putative toxin gene homologs from Russell’s viper (Daboia russelii) using whole-genome sequencing data obtained from shed skin. When compared with the major venom proteins in Russell’s viper studied previously, we found 45–100% sequence similarity between the venom proteins and their putative homologs in the skin. Additionally, comparative analyses of 20 putative toxin gene family homologs provided evidence of unique sequence motifs in nerve growth factor (NGF), platelet derived growth factor (PDGF), Kunitz/Bovine pancreatic trypsin inhibitor (Kunitz BPTI), cysteine-rich secretory proteins, antigen 5, andpathogenesis-related1 proteins (CAP) and cysteine-rich secretory protein (CRISP). In those derived proteins, we identified V11 and T35 in the NGF domain; F23 and A29 in the PDGF domain; N69, K2 and A5 in the CAP domain; and Q17 in the CRISP domain to be responsible for differences in the largest pockets across the protein domain structures in crotalines, viperines and elapids from the in silico structure-based analysis. Similarly, residues F10, Y11 and E20 appear to play an important role in the protein structures across the kunitz protein domain of viperids and elapids. Our study highlights the usefulness of shed skin in obtaining good quality high-molecular weight DNA for comparative genomic studies, and provides evidence towards the unique features and evolution of putative venom gene homologs in vipers.

A Review and Database of Snake Venom Proteomes

Advances in the last decade combining transcriptomics with established proteomics methods have made possible rapid identification and quantification of protein families in snake venoms. Although over 100 studies have been published, the value of this information is increased when it is collated, allowing rapid assimilation and evaluation of evolutionary trends, geographical variation, and possible medical implications. This review brings together all compositional studies of snake venom proteomes published in the last decade. Compositional studies were identified for 132 snake species: 42 from 360 (12%) Elapidae (elapids), 20 from 101 (20%) Viperinae (true vipers), 65 from 239 (27%) Crotalinae (pit vipers), and five species of non-front-fanged snakes. Approximately 90% of their total venom composition consisted of eight protein families for elapids, 11 protein families for viperines and ten protein families for crotalines. There were four dominant protein families: phospholipase A₂s (the most common across all front-fanged snakes), metalloproteases, serine proteases and three-finger toxins. There were six secondary protein families: cysteine-rich secretory proteins, l-amino acid oxidases, kunitz peptides, C-type lectins/snaclecs, disintegrins and natriuretic peptides. Elapid venoms contained mostly three-finger toxins and phospholipase A₂s and viper venoms metalloproteases, phospholipase A₂s and serine proteases. Although 63 protein families were identified, more than half were present in <5% of snake species studied and always in low abundance. The importance of these minor component proteins remains unknown.

Strategies in 'snake venomics' aiming at an integrative view of compositional, functional, and immunological characteristics of venoms

This work offers a general overview on the evolving strategies for the proteomic analysis of snake venoms, and discusses how these may be combined through diverse experimental approaches with the goal of achieving a more comprehensive knowledge on the compositional, toxic, and immunological characteristics of venoms. Some recent developments in this field are summarized, highlighting how strategies have evolved from the mere cataloguing of venom components (proteomics/venomics), to a broader exploration of their immunological (antivenomics) and functional (toxicovenomics) characteristics. Altogether, the combination of these complementary strategies is helping to build a wider, more integrative view of the life-threatening protein cocktails produced by venomous snakes, responsible for thousands of deaths every year.

Venomics: integrative venom proteomics and beyond*

Venoms are integrated phenotypes that evolved independently in, and are used for predatory and defensive purposes by, a wide phylogenetic range of organisms. The same principles that contribute to the evolutionary success of venoms, contribute to making the study of venoms of great interest in such diverse fields as evolutionary ecology and biotechnology. Evolution is profoundly contingent, and nature also reinvents itself continuosly. Changes in a complex phenotypic trait, such as venom, reflect the influences of prior evolutionary history, chance events, and selection. Reconstructing the natural history of venoms, particularly those of snakes, which will be dealt with in more detail in this review, requires the integration of different levels of knowledge into a meaningful and comprehensive evolutionary framework for separating stochastic changes from adaptive evolution. The application of omics technologies and other disciplines have contributed to a qualitative and quantitative advance in the road map towards this goal. In this review we will make a foray into the world of animal venoms, discuss synergies and complementarities of the different approaches used in their study, and identify current bottlenecks that prevent inferring the evolutionary mechanisms and ecological constraints that molded snake venoms to their present-day variability landscape.

Gene expression profiling of the venom gland from the Venezuelan mapanare (Bothrops colombiensis) using expressed sequence tags (ESTs)

BACKGROUND

Bothrops colombiensis is a highly dangerous pit viper and responsible for over 70% of snakebites in Venezuela. Although the composition in B. colombiensis venom has been identified using a proteome analysis, the venom gland transcriptome is currently lacking.

RESULTS

We constructed a cDNA library from the venom gland of B. colombiensis, and a set of 729 high quality expressed sequence tags (ESTs) was identified. A total number of 344 ESTs (47.2% of total ESTs) was related to toxins. The most abundant toxin transcripts were metalloproteinases (37.5%), phospholipases A2s (PLA2, 29.7%), and serine proteinases (11.9%). Minor toxin transcripts were linked to waprins (5.5%), C-type lectins (4.1%), ATPases (2.9%), cysteine-rich secretory proteins (CRISP, 2.3%), snake venom vascular endothelium growth factors (svVEGF, 2.3%), L-amino acid oxidases (2%), and other putative toxins (1.7%). While 160 ESTs (22% of total ESTs) coded for translation proteins, regulatory proteins, ribosomal proteins, elongation factors, release factors, metabolic proteins, and immune response proteins. Other proteins detected in the transcriptome (87 ESTs, 11.9% of total ESTs) were undescribed proteins with unknown functions. The remaining 138 (18.9%) cDNAs had no match with known GenBank accessions.

CONCLUSION

This study represents the analysis of transcript expressions and provides a physical resource of unique genes for further study of gene function and the development of novel molecules for medical applications.