Cytotoxic, Antiproliferative and Apoptosis-inducing Activity of L-Amino Acid Oxidase from MalaysianCalloselasma rhodostomaon Human Colon Cancer Cells

A review on NLRP3 inflammasome modulation by animal venom proteins/peptides: mechanisms and therapeutic insights

The venom peptides from terrestrial as well as aquatic species have demonstrated potential in regulating the NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, a sophisticated assemblage present in immune cells responsible for detecting and responding to external mediators. The NLRP3 inflammasome plays a role in several pathological conditions such as type 2 diabetes, hyperglycemia, Alzheimer's disease, obesity, autoimmune disorders, and cardiovascular disorders. Venom peptides derived from animal venoms have been discovered to selectively induce certain signalling pathways, such as the NLRP3 inflammasome, mitogen-activated protein kinase (MAPK), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). Experimental evidence has demonstrated that venom peptides can regulate the expression and activation of the NLRP3 inflammasome, resulting in the secretion of pro-inflammatory cytokines including interleukin (IL)-1β and IL-18. Furthermore, these peptides have been discovered to impede the activation of the NLRP3 inflammasome, therefore diminishing inflammation and tissue injury. The functional properties of venom proteins and peptides obtained from snakes, bees, wasps, and scorpions have been thoroughly investigated, specifically targeting the NLRP3 inflammasome pathway, venom proteins and peptides have shown promise as therapeutic agents for the treatment of certain inflammatory disorders. This review discusses the pathophysiology of NLRP3 inflammasome in the onset of various diseases, role of venom as therapeutics. Further, various venom components and their role in the modulation of NLRP3 inflammasome are discoursed. A substantial number of venomous animals and their toxins are yet unexplored, and to comprehensively grasp the mechanisms of action of them and their potential as therapeutic agents, additional research is required which can lead to the development of novel therapeutics.

Deciphering toxico-proteomics of Asiatic medically significant venomous snake species: A systematic review and interactive data dashboard

Snakebite envenomation (SBE) is a neglected tropical disease (NTD) with an approximate 1.8 million cases annually. The tremendous figure is concerning, and the currently available treatment for snakebite envenomation is antivenom. However, the current antivenom has limited cross-neutralisation activity due to the variations in snake venom composition across species and geographical locations. The proteomics of medically important venomous species is essential as they study the venom compositions within and among different species. The advancement of sophisticated proteomic approaches allows intensive investigation of snake venoms. Nevertheless, there is a need to consolidate the venom proteomics profiles and distribution analysis to examine their variability patterns. This review systematically analysed the proteomics and toxicity profiles of medically important venomous species from Asia across different geographical locations. An interactive dashboard - Asiatic Proteomics Interactive Datasets was curated to consolidate the distribution patterns of the venom compositions, serve as a comprehensive directory for large-scale comparative meta-analyses. The population proteomics demonstrate higher diversities in the predominant venom toxins. Besides, inter-regional differences were also observed in Bungarus sp., Naja sp., Calliophis sp., and Ophiophagus hannah venoms. The elapid venoms are predominated with three-finger toxins (3FTXs) and phospholipase A2 (PLA2). Intra-regional variation is only significantly observed in Naja naja venoms. Proteomics diversity is more prominent in viper venoms, with widespread dominance observed in snake venom metalloproteinase (SVMP) and snake venom serine protease (SVSP). Correlations exist between the proteomics profiles and the toxicity (LD50) of the medically important venomous species. Additionally, the predominant toxins, alongside their pathophysiological effects, were highlighted and discussed as well. The insights of interactive toxico-proteomics datasets provide comprehensive frameworks of venom dynamics and contribute to developing antivenoms for snakebite envenomation. This could reduce misdiagnosis of SBE and accelerate the researchers' data mining process.

Emerging anticancer potential and mechanisms of snake venom toxins: A review

Animal-derived venom, like snake venom, has been proven to be valuable natural resources for the drug development. Previously, snake venom was mainly investigated in its pharmacological activities in regulating coagulation, vasodilation, and cardiovascular function, and several marketed cardiovascular drugs were successfully developed from snake venom. In recent years, snake venom fractions have been demonstrated with anticancer properties of inducing apoptotic and autophagic cell death, restraining proliferation, suppressing angiogenesis, inhibiting cell adhesion and migration, improving immunity, and so on. A number of active anticancer enzymes and peptides have been identified from snake venom toxins, such as L-amino acid oxidases (LAAOs), phospholipase A2 (PLA2), metalloproteinases (MPs), three-finger toxins (3FTxs), serine proteinases (SPs), disintegrins, C-type lectin-like proteins (CTLPs), cell-penetrating peptides, cysteine-rich secretory proteins (CRISPs). In this review, we focus on summarizing these snake venom-derived anticancer components on their anticancer activities and underlying mechanisms. We will also discuss their potential to be developed as anticancer drugs in the future.

Three snake venoms from Bothrops genus induced apoptosis and cell cycle arrest in K562 human leukemic cell line

Cancer is indisputably one of the leading causes of death worldwide. Snake venoms are a potential source of bioactive compounds, complex mixtures constituted mainly of proteins and peptides with several pharmacological possibilities, including the potential to inhibit tumoral cell growth. In the present study, it was evaluated the antitumor effect of crude venom of Bothrops erythromelas (BeV), Bothrops jararaca (from Southern and Southeastern- BjsV and BjsdV, respectively) and Bothrops alternatus (BaV) in in vitro Chronic myeloid leukemia (CML) cancer cell line model. After 24 h of cell exposure to 10 and 50 μg/mL, BjsV, BjsdV, and BaV exerted a decrease in cell viability in both concentrations. BeV was not cytotoxic and, therefore wasn't chosen for further mechanism of action investigation. Furthermore, morphological alterations show modification typical of apoptosis. Also, was observes a significant cell cycle arrest in the S phase by BjsdV and BaV treatment. Flow cytometry evidenced the involvement of changes in the cell membrane permeability and the mitochondrial function by BjsV and BjsdV, corroborating with the triggering of the apoptotic pathway by the venom administration. BjsV, BjsdV, and BaV also led to extensive DNA damage and were shown to modulate the gene expression of transcripts related to the cell cycle progression and suppress the expression of the BCR-ABL1 oncogene. Altogether, these findings suggest that the venoms trigger the apoptosis pathway due to mitochondrial damage and cell cycle arrest, with modulation of intracellular pathways important for CML progression. Thus, indicating the pharmacological potential of these venoms in the development of new antitumoral compounds.

Action mechanism of snake venom l-amino acid oxidase and its double-edged sword effect on cancer treatment: Role of pannexin 1-mediated interleukin-6 expression

Snake venom l-amino acid oxidases (svLAAOs) have been recognized as promising candidates for anticancer therapeutics. However, multiple aspects of their catalytic mechanism and the overall responses of cancer cells to these redox enzymes remain ambiguous. Here, we present an analysis of the phylogenetic relationships and active site-related residues among svLAAOs and reveal that the previously proposed critical catalytic residue His 223 is highly conserved in the viperid but not the elapid svLAAO clade. To gain further insight into the action mechanism of the elapid svLAAOs, we purify and characterize the structural, biochemical, and anticancer therapeutic potentials of the Thailand elapid snake Naja kaouthia LAAO (NK-LAAO). We find that NK-LAAO, with Ser 223, exhibits high catalytic activity toward hydrophobic l-amino acid substrates. Moreover, NK-LAAO induces substantial oxidative stress-mediated cytotoxicity with the magnitude relying on both the levels of extracellular hydrogen peroxide (H2O2) and intracellular reactive oxygen species (ROS) generated during the enzymatic redox reactions, but not being influenced by the N-linked glycans on its surface. Unexpectedly, we discover a tolerant mechanism deployed by cancer cells to dampen the anticancer activities of NK-LAAO. NK-LAAO treatment amplifies interleukin (IL)-6 expression via the pannexin 1 (Panx1)-directed intracellular calcium (iCa2+) signaling pathway to confer adaptive and aggressive phenotypes on cancer cells. Accordingly, IL-6 silencing renders cancer cells vulnerable to NK-LAAO-induced oxidative stress together with abrogating NK-LAAO-stimulated metastatic acquisition. Collectively, our study urges caution when using svLAAOs in cancer treatment and identifies the Panx1/iCa2+/IL-6 axis as a therapeutic target for improving the effectiveness of svLAAOs-based anticancer therapies.

Typical response of CD14++CD16– monocyte to knee synovial derived mediators as a key target to overcome the onset and progression of osteoarthritis

Objective

Synovitis with increased infiltration of immune cells is observed in osteoarthritis (OA). Given the inflammatory condition of synovitis, we explored the protein profile of OA synovium (OAS) and its effect on circulating monocytes activation, migration, and functional commitments.

Methods

Knee-synovium was acquired from end-stage OA (N = 8) and trauma patients (Trauma baseline control: TBC; N = 8) for characterization using H&E histology, IHC (iNOS), LCMS-QTOF, and MALDI-imaging. Response of peripheral blood monocytes to OAS conditioned-media (OACM) was observed using transwell (n = 6). The migrated cells were captured in SEM, quantified using phase-contrast microphotographs, and their activation receptors (CCR2, CXCR2, CX3CR1, and CD11b), pro-inflammatory genes, and phagocytic potential were studied using flow cytometry, gene expression array/qPCR, and latex beads (LB) phagocytosis assay, respectively.

Results

The Venn diagram displayed 119 typical proteins in OAS, while 55 proteins in TBCS. The STRING protein network analysis indicated distinctive links between proteins and gene ontology (GO) and revealed proteins associated with leukocyte-mediated immunity in OAS as compared to TBC. The MALDI-imaging showed typical localized proteins at 2234.97, 2522.61, 2627.21, 3329.50, and 3539.69 m/z and IHC confirmed pro-inflammatory iNOS expression in OA synovium. CD14++CD16– classical monocytes significantly migrated in OACM and expressed CCR2, CXCR2, and CD11b receptors, TNFRSF11A, MAPK1, S100A8, HSPB1, ITGAL, NFATC1, IL13RA1, CD93, IL-1β, TNF-α, and MYD88 genes and increased LB uptake as compared to SFM.

Conclusion

Our findings suggest that the differential protein profile of OA synovium and the classical monocytes migrated, activated, and functionally committed in response to these mediators could be of therapeutic advantage.

Reactive oxygen species as a double-edged sword: The role of oxidative enzymes in antitumor therapy

A number of approaches have been developed over the years to manage cancer, such as chemotherapy using low-molecular-mass molecules and radiotherapy. Here, enzymes can also find useful applications. Among them, oxidases have attracted attention because of their ability to produce reactive oxygen species (ROS, especially hydrogen peroxide) in tumors and potentially modulate the production of this cytotoxic compound when enzymes active on substrates present in low amounts are used, such as the d-amino acid oxidase and d-amino acid couple system. These treatments have been also developed for additional cancer treatment approaches, such as phototherapy, nutrient starvation, and metal-induced hydroxyl radical production. In addition, to improve tumor specificity and decrease undesired side effects, oxidases have been targeted by means of nanotechnologies and protein engineering (i.e., by designing chimeric proteins able to accumulate in the tumor). The most recent advances obtained by using six different oxidases (i.e., the FAD-containing enzymes glucose oxidase, d- and l-amino acid oxidases, cholesterol oxidase and xanthine oxidase, and the copper-containing amine oxidase) have been reported. Anticancer therapy based on oxidase-based ROS production has now reached maturity and can be applied in the clinic.

Anticancer Properties of Asian Water Monitor Lizard (Varanus salvator), Python (Malayopython reticulatus) and Tortoise (Cuora kamaroma amboinensis)

BACKGROUND

Cancer contributes to significant morbidity and mortality despite advances in treatment and supportive care. There is a need for the identification of effective anticancer agents. Reptiles such as tortoise, python, and water monitor lizards are exposed to heavy metals, tolerate high levels of radiation, feed on rotten/germ-infested feed, thrive in unsanitary habitat and yet have prolonged lifespans. Such species are rarely reported to develop cancer, suggesting the presence of anticancer molecules/mechanisms.

METHODS

Here, we tested effects from sera of Asian water monitor lizard (Varanus salvator), python (Malayopython reticulatus) and tortoise (Cuora kamaroma amboinensis) against cancer cells. Sera were collected and cytotoxicity assays were performed using prostate cancer cells (PC3), Henrietta Lacks cervical adenocarcinoma cells (HeLa) and human breast adenocarcinoma cells (MCF7), as well as human keratinized skin cells (Hacat), by measuring lactate dehydrogenase release as an indicator for cell death. Growth inhibition assays were performed to determine the effects on cancer cell proliferation. Liquid chromatography mass spectrometry was performed for molecular identification.

RESULTS

The findings revealed that reptilian sera, but not bovine serum, abolished viability of Hela, PC3 and MCF7 cells. Samples were subjected to liquid chromatography mass spectrometry, which detected 57 molecules from V. salvator, 81 molecules from Malayopython reticulatus and 33 molecules from C. kamaroma amboinensis and putatively identified 9 molecules from V. salvator, 20 molecules from Malayopython reticulatus and 9 molecules from C. kamaroma amboinensis when matched against METLIN database. Based on peptide amino acid composition, binary profile, dipeptide composition and pseudo-amino acid composition, 123 potential Anticancer Peptides (ACPs) were identified from 883 peptides from V. salvator, 306 potential ACPs from 1074 peptides from Malayopython reticulatus and 235 potential ACPs from 885 peptides from C. kamaroma amboinensis.

CONCLUSION

To our knowledge, for the first time, we reported comprehensive analyses of selected reptiles' sera using liquid chromatography mass spectrometry, leading to the identification of potentially novel anticancer agents. We hope that the discovery of molecules from these animals will pave the way for the rational development of new anticancer agents.

A comparative study on the leishmanicidal activity of the L-amino acid oxidases BjussuLAAO-II and BmooLAAO-II isolated from Brazilian Bothrops snake venoms

This study aims to examine whether two L-amino acid oxidases isolated from Bothrops snake venom (SV-LAAOs) were cytotoxic to Leishmania (Leishmania) amazonensis and Leishmania (Viannia) braziliensis, two causative agents of leishmaniasis, which is an endemic disease in tropical and subtropical countries. The SV-LAAOs BjussuLAAO-II and BmooLAAO-II were isolated from Bothrops jararacussu and Bothrops moojeni venom, respectively, through a three-step chromatography process that used molecular exclusion, hydrophobic interaction, and affinity columns. BmooLAAO-II is a new SV-LAAO isoform that we isolated in this study. The purified BjussuLAAO-II and BmooLAAO-II had high L-amino acid oxidase-specific activity: 3481.17 and 4924.77 U/mg/min, respectively. Both SV-LAAOs were strongly cytotoxic to the two Leishmania species, even at low concentrations. At the same concentration, BjussuLAAO-II and BmooLAAO-II exerted different cytotoxic effects on the parasites. We reported for the first time that the SV-LAAOs suppressed cell proliferation and altered the mitochondrial membrane potential of the two Leishmania species. Surprisingly, BjussuLAAO-II increased the intracellular reactive oxygen species production only in L. (L.) amazonensis, while BmooLAAO-II increased the intracellular reactive oxygen species production only in L. (V.) braziliensis, indicating that these SV-LAAOs had a certain specificity of action.

Crocodylus porosus: a potential source of anticancer molecules

Background

Cancer remains a global threat resulting in significant morbidity and mortality despite advances in therapeutic interventions, suggesting urgency for identification of anticancer agents. Crocodiles thrive in polluted habitat, feed on germ-infested meat, are exposed to carcinogenic heavy metals, are the very few species to survive the catastrophic Cretaceous–Paleogene extinction event, yet have a prolonged lifespan and rarely been reported to develop cancer. Therefore, we hypothesised that animals living in polluted environments such as crocodiles possess anticancer molecules/mechanisms.

Methods

Crocodylus porosus was procured, blood collected, dissected and lysates prepared from internal organs. Organ lysates and sera were tested for growth inhibition, cytotoxic effects and cell survival against HeLa, PC3 and MCF7 cells and subjected to liquid chromatography mass spectrometry. RNA transcriptome analysis and differential gene analysis were performed using Galaxy Bioinformatics.

Results

Sera exhibited potent growth inhibition and cytotoxic effects against cancer cells. 80 molecules were detected from C. porosus and 19 molecules were putatively identified. Additionally, more than 100 potential anticancer peptides were identified from sera using bioinformatics based on peptide amino acid composition, binary profile, dipeptide composition and pseudo-amino acid composition. Following transcriptome analysis, 14 genes in treated HeLa cells, 51 genes in treated MCF7 cells and 2 genes in treated PC3 cells, were found to be expressed, compared with untreated controls.

Conclusion

Animals residing in polluted milieus are an unexploited source for prospective pharmaceutical drugs, and could lead to identification of novel antitumour compound(s) and/or further understanding of the mechanisms of cancer resistance.

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.

Structure-Function Studies and Mechanism of Action of Snake Venom L-Amino Acid Oxidases

Snake venom L-amino acid oxidases (SV-LAAOs) are the least studied venom enzymes. These enzymes catalyze the stereospecific oxidation of an L-amino acid to their corresponding α-keto acid with the liberation of hydrogen peroxide (H₂O₂) and ammonia (NH₃). They display various pathological and physiological activities including induction of apoptosis, edema, platelet aggregation/inhibition, hemorrhagic, and anticoagulant activities. They also show antibacterial, antiviral and leishmanicidal activity and have been used as therapeutic agents in some disease conditions like cancer and anti-HIV drugs. Although the crystal structures of six SV-LAAOs are present in the Protein Data Bank (PDB), there is no single article that describes all of them in particular. To better understand their structural properties and correlate it with their function, the current work describes structure characterization, structure-based mechanism of catalysis, inhibition and substrate specificity of SV-LAAOs. Sequence analysis indicates a high sequence identity (>84%) among SV-LAAOs, comparatively lower sequence identity with Pig kidney D-amino acid oxidase (<50%) and very low sequence identity (<24%) with bacterial LAAOs, Fugal (L-lysine oxidase), and Zea mays Polyamine oxidase (PAAO). The three-dimensional structure of these enzymes are composed of three-domains, a FAD-binding domain, a substrate-binding domain and a helical domain. The sequence and structural analysis indicate that the amino acid residues in the loops vary in length and composition due to which the surface charge distribution also varies that may impart variable substrate specificity to these enzymes. The active site cavity volume and its average depth also vary in these enzymes. The inhibition of these enzymes by synthetic inhibitors will lead to the production of more potent antivenoms against snakebite envenomation.

Malaysian Cobra Venom: A Potential Source of Anti-Cancer Therapeutic Agents

Cancer is a deadly disease and there is an urgent need for the development of effective and safe therapeutic agents to treat it. Snake venom is a complex mixture of bioactive proteins that represents an attractive source of novel and naturally-derived anticancer agents. Malaysia is one of the world’s most biodiverse countries and is home to various venomous snake species, including cobras. Naja kaouthia, Naja sumatrana, and Ophiophagus hannah are three of the most common cobra species in Malaysia and are of medical importance. Over the past decades, snake venom has been identified as a potential source of therapeutic agents, including anti-cancer agents. This present review highlights the potential anticancer activity of the venom and purified venom protein of N. kaouthia, N. sumatrana, and O. hannah. In conclusion, this review highlights the important role of the venom from Malaysian cobras as an important resource that researchers can exploit to further investigate its potential in cancer treatment.