Scorpion Toxins and Ion Channels: Potential Applications in Cancer Therapy

Scorpiones, Scolopendra and Gekko Inhibit Lung Cancer Growth and Metastasis by Ameliorating Hypoxic Tumor Microenvironment via PI3K/AKT/mTOR/HIF-1α Signaling Pathway

OBJECTIVE

To investigate whether Buthus martensii karsch (Scorpiones), Scolopendra subspinipes mutilans L. Koch (Scolopendra) and Gekko gecko Linnaeus (Gekko) could ameliorate the hypoxic tumor microenvironment and inhibit lung cancer growth and metastasis by regulating phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin/hypoxia-inducible factor-1α (PI3K/AKT/mTOR/HIF-1α) signaling pathway.

METHODS

Male C57BL/6J mice were inoculated with luciferase labeled LL/2-luc-M38 cell suspension to develop lung cancer models, with rapamycin and cyclophosphamide as positive controls. Carboxy methyl cellulose solutions of Scorpiones, Scolopendra and Gekko were administered intragastrically as 0.33, 0.33, and 0.83 g/kg, respectively once daily for 21 days. Fluorescent expression were detected every 7 days after inoculation, and tumor growth curves were plotted. Immunohistochemistry was performed to determine CD31 and HIF-1α expressions in tumor tissue and microvessel density (MVD) was analyzed. Western blot was performed to detect the expression of PI3K/AKT/mTOR/HIF-1α signaling pathway-related proteins. Enzyme-linked immunosorbent assay was performed to detect serum basic fibroblast growth factor (bFGF), transforming growth factor-β1 (TGF-β1) and vascular endothelial growth factor (VEGF) in mice.

RESULTS

Scorpiones, Scolopendra and Gekko prolonged the survival time and inhibited lung cancer metastasis and expression of HIF-1α (all P<0.01). Moreover, Scorpiones, Scolopendra and Gekko inhibited the phosphorylation of AKT and ribosomal protein S6 kinase (p70S6K) (P<0.05 or P<0.01). In addition, they also decreased the expression of CD31, MVD, bFGF, TGF-β1 and VEGF compared with the model group (P<0.05 or P<0.01).

CONCLUSION

Scorpiones, Scolopendra and Gekko all showed beneficial effects on lung cancer by ameliorating the hypoxic tumor microenvironment via PI3K/AKT/mTOR/HIF-1α signaling pathway.

Phytochemical Modulation of Ion Channels in Oncologic Symptomatology and Treatment

Modern chemotherapies offer a broad approach to cancer treatment but eliminate both cancer and non-cancer cells indiscriminately and, thus, are associated with a host of side effects. Advances in precision oncology have brought about new targeted therapeutics, albeit mostly limited to a subset of patients with an actionable mutation. They too come with side effects and, ultimately, 'self-resistance' to the treatment. There is recent interest in the modulation of ion channels, transmembrane proteins that regulate the flow of electrically charged molecules in and out of cells, as an approach to aid treatment of cancer. Phytochemicals have been shown to act on ion channels with high specificity regardless of the tumor's genetic profile. This paper explores the use of phytochemicals in cancer symptom management and treatment.

Astragaloside IV-PESV inhibits prostate cancer tumor growth by restoring gut microbiota and microbial metabolic homeostasis via the AGE-RAGE pathway

BACKGROUND

Prostate cancer (PCa) is becoming the most common malignancy in men worldwide. We investigated the effect of astragaloside IV combined with PESV on the gut microbiota and metabolite of PCa mice and the process of treating PCa.

METHODS

Nude mice were genetically modified to develop tumors characteristic of PCa. The treatment of PCa mice involved the administration of a combination of astragaloside IV and peptides derived from scorpion venom (PESV). Feces were collected for both 16 S rDNA and metabolic analysis. Fecal supernatant was extracted and used for fecal transplantation in PCa mice. Tumor development was observed in both PCa mice and nude mice. Tumor histopathology was examined, and the expression of inflammatory factors and the AGE-RAGE axis in PCa tissues were analyzed.

RESULTS

PCa mice treated with Astragaloside IV in combination with PESV showed a significant reduction in tumor volume and weight, and stabilization of gut microbiota and metabolites. At the Genus level, significant differences were observed in Porphyromonas, Corynebacterium, Arthromitus and Blautia, and the differential metabolites were PA16_016_0, Astragaloside+, Vitamin A acid, Nardosinone, a-Nortestoster, D-Pantethine, Hypoxanthine, Pregnenolone, cinnamic acid, Pyridoxa, Cirtruline and Xanthurenate. There was a correlation between gut microbiota and metabolites. After the fecal transplantation, tumor growth was effectively suppressed in the PCa mice. Notably, both the mRNA and protein levels of the receptor for advanced glycation end products (RAGE) were significantly decreased. Furthermore, the expression of inflammatory factors, namely NF-κB, TNF-α, and IL-6, in the tumor tissues was significantly attenuated. Conversely, upregulation of RAGE led to increased inflammation and reversed tumor growth in the mice.

CONCLUSION

Astragaloside IV combined with PESV could treat PCa by intervening in gut microbiota composition and metabolite by targeting RAGE.

Antimicrobial, toxicological, and antigenic characteristics of three scorpion venoms from Colombia: Centruroides margaritatus, Tityus pachyurus and Tityus n. sp. aff. metuendus

The venom fractions of three buthid scorpion species from Colombia, C. margaritatus, T. pachyurus and T. n. sp. aff. metuendus, were examined for antimicrobial and toxicity toward mice and insects. The three venoms were separated into individual fractions using RP-HPLC, resulting in 85 fractions from C. margaritatus, 106 from T. pachyurus, and 70 from T. n. sp. aff. metuendus. The major fractions from the three scorpion venoms, which were eluted between 35 and 50 min, were tested for antimicrobial activity and toxicity. It was confirmed that the venom of the three species contains fractions with antimicrobial peptides that were evaluated against two bacterial strains of public health importance, Pseudomonas aeruginosa and Staphylococcus aureus. The venom of C. margaritatus had two antimicrobial fractions that showed activity against the named tested strains. The venom of T. pachyurus had three fractions that showed activity against S. aureus and two against both bacterial strains. Finally, the venom of T. n. sp. aff. metuendus had one fraction that showed activity against S. aureus, and five fractions showed activity against both bacterial strains. Also, some peptide fractions from the three venoms were toxic to mice. Last, the venoms of C. margaritatus and T. pachyurus were used as immunogens to obtain neutralizing antibodies against its respective venoms and to observe antibody recognition to related and unrelated scorpion venoms. A total of 15 mg of lyophilized antibodies were able to neutralize 1.5⋅LD50 of the venoms from T. n. sp. aff. metuendus, T. pachyurus and C. margaritatus, respectively. This information provides valuable insights into the diversity of each species' venom and their potential role in antimicrobial and venom toxicity.

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

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

Neurotoxin-Derived Optical Probes for Biological and Medical Imaging

The superb specificity and potency of biological toxins targeting various ion channels and receptors are of major interest for the delivery of therapeutics to distinct cell types and subcellular compartments. Fused with reporter proteins or labelled with fluorophores and nanocomposites, animal toxins and their detoxified variants also offer expanding opportunities for visualisation of a range of molecular processes and functions in preclinical models, as well as clinical studies. This article presents state-of-the-art optical probes derived from neurotoxins targeting ion channels, with discussions of their applications in basic and translational biomedical research. It describes the design and production of probes and reviews their applications with advantages and limitations, with prospects for future improvements. Given the advances in imaging tools and expanding research areas benefiting from the use of optical probes, described here resources should assist the discovery process and facilitate high-precision interrogation and therapeutic interventions.

Design of ion channel blocking, toxin-like Kunitz inhibitor peptides from the tapeworm, Echinococcus granulosus, with potential anti-cancer activity

Over-expression of K+ channels has been reported in human cancers and is associated with the poor prognosis of several malignancies. EAG1, a particular potassium ion channel, is widely expressed in the brain but poorly expressed in other normal tissues. Kunitz proteins are dominant in metazoan including the dog tapeworm, Echinococcus granulosus. Using computational analyses on one A-type potassium channel, EAG1, and in vitro cellular methods, including major cancer cell biomarkers expression, immunocytochemistry and whole-cell patch clamp, we demonstrated the anti-tumor activity of three synthetic small peptides derived from E. granulosus Kunitz4 protease inhibitors. Experiments showed induced significant apoptosis and inhibition of proliferation in both cancer cell lines via disruption in cell-cycle transition from the G0/G1 to S phase. Western blotting showed that the levels of cell cycle-related proteins including P27 and P53 were altered upon kunitz4-a and kunitz4-c treatment. Patch clamp analysis demonstrated a significant increase in spontaneous firing frequency in Purkinje neurons, and exposure to kunitz4-c was associated with an increase in the number of rebound action potentials after hyperpolarized current. This noteworthy component in nature could act as an ion channel blocker and is a potential candidate for cancer chemotherapy based on potassium channel blockage.

The recent progress of peptide regulators for the Wnt/β-catenin signaling pathway

Wnt signaling plays an important role in many biological processes such as stem cell self-renewal, cell proliferation, migration, and differentiation. The β-catenin-dependent signaling pathway mainly regulates cell proliferation, differentiation, and migration. In the Wnt/β-catenin signaling pathway, the Wnt family ligands transduce signals through LRP5/6 and Frizzled receptors to the Wnt/β-catenin signaling cascades. Wnt-targeted therapy has garnered extensive attention. The most commonly used approach in targeted therapy is small-molecule regulators. However, it is difficult for small-molecule regulators to make great progress due to their inherent defects. Therapeutic peptide regulators targeting the Wnt signaling pathway have become an alternative therapy, promising to fill the gaps in the clinical application of small-molecule regulators. In this review, we describe recent advances in peptide regulators for Wnt/β-catenin signaling.

EFFECT OF SCORPION VENOM TOXINS ON STRUCTURAL AND FUNCTIONAL PARAMETERS OF INTERNAL ORGANS, INCLUDING KIDNEYS (REVIEW)

OBJECTIVE

The aim: To establish patterns of structural and functional changes in internal organs, including kidneys, under the conditions of exposure to scorpion venom toxins.

PATIENTS AND METHODS

Materials and methods: A thorough literature analysis was conducted on the basis of PubMed, Google Scholar, Web of Science, and Scopus databases. When processing the search results, we chose the newest publications up to 5 years old or the most thorough publications that vividly described the essence of our topic.

CONCLUSION

Conclusions: The venom of various species of scorpions exhibits a wide range of biological activity. Acting on the structures of the central and peripheral nervous system, the toxins of scorpion venom cause the development of paralysis, convulsions, brain inflammation, hemorrhagic and ischemic strokes. Under conditions of influence on the cardiovascular system, damage to the endothelial lining of the vascular wall, disturbances in heart rhythm, conduction, and the development of destructive changes in the myocardium are characteristic. Data on kidney damage due to scorpion bites require a more detailed study, as information on microscopic and submicroscopic changes in the structure of the organ is too limited. However, cases of the development of tubular necrosis, interstitial nephritis, and kidney infarction are currently known.

Astragalus–Scorpion Drug Pair Inhibits the Development of Prostate Cancer by Regulating GDPD4-2/PI3K/AKT/mTOR Pathway and Autophagy

Objective: Prostate cancer (PCa) is an epithelial malignancy of the prostate that currently lacks effective treatment. Traditional Chinese medicine (TCM) can play an anticancer role through regulating the immune system, anti-tumor angiogenesis, regulating tumor cell apoptosis, autophagy dysfunction, and other mechanisms. This study attempted to explore the active ingredients and potential mechanism of action of the Astragalus–Scorpion (A–S) drug pair in PCa, in order to provide new insights into the treatment of PCa.

Methods: Network pharmacology was used to analyze the A–S drug pair and PCa targets. Bioinformatics analysis was used to analyze the LncRNAs with significant differences in PCa. The expression of LC3 protein was detected by immunofluorescence. CCK8 was used to detect cell proliferation. The expressions of GDPD4-2, AC144450.1, LINC01513, AC004009.2, AL096869.1, AP005210.1, and BX119924.1 were detected by RT-qPCR. The expression of the PI3K/AKT/mTOR pathway and autophagy-related proteins were detected by western blot. LC-MS/MS was used to identify the active components of Astragalus and Scorpion.

Results: A–S drug pair and PCa have a total of 163 targets, which were mainly related to the prostate cancer and PI3K/AKT pathways. A–S drug pair inhibited the formation of PCa, promoted the expression of LC3Ⅱ and Beclin1 proteins, and inhibited the expression of P62 and PI3K–AKT pathway proteins in PCa mice. Astragaloside IV and polypeptide extract from scorpion venom (PESV) were identified as the main active components of the A–S drug pair. GDPD4-2 was involved in the treatment of PCa by Astragaloside IV-PESV. Silencing GDPD4-2 reversed the therapeutic effects of Astragaloside IV-PESV by regulating the PI3K/AKT/mTOR pathway.

Conclusion: Astragaloside IV-PESV is the main active components of A–S drug pair treated PCa by regulating the GDPD4-2/PI3K–AKT/mTOR pathway and autophagy.

Ion Channels and Transporters as Therapeutic Agents: From Biomolecules to Supramolecular Medicinal Chemistry

Ion channels and transporters typically consist of biomolecules that play key roles in a large variety of physiological and pathological processes. Traditional therapies include many ion-channel blockers, and some activators, although the exact biochemical pathways and mechanisms that regulate ion homeostasis are yet to be fully elucidated. An emerging area of research with great innovative potential in biomedicine pertains the design and development of synthetic ion channels and transporters, which may provide unexplored therapeutic opportunities. However, most studies in this challenging and multidisciplinary area are still at a fundamental level. In this review, we discuss the progress that has been made over the last five years on ion channels and transporters, touching upon biomolecules and synthetic supramolecules that are relevant to biological use. We conclude with the identification of therapeutic opportunities for future exploration.

Molecular Cloning and Functional Identification of the Antimicrobial Peptide Gene Ctri9594 from the Venom of the Scorpion Chaerilus tricostatus

Scorpion venom is a mixture of bioactive peptides, among which neurotoxins and antimicrobial peptides serve especially vital functions. Scorpion venom peptides in Buthidae species have been well described, but toxic peptides from non-Buthidae species have been under-investigated. Here, an antimicrobial peptide gene, Ctri9594, was cloned and functionally identified from the venom of the scorpion Chaerilus tricostatus. The precursor nucleotide sequence of Ctri9594 is 199 nt in length, including a 43 nt 5′ UTR, 115 nt 3′ UTR and 210 nt ORF. The ORF encodes 69 amino acid residues, containing a 21 aa signal peptide, 14 aa mature peptide, 3 aa C-terminal posttranslational processing signal and 31 aa propeptide. Multiple sequence alignment and evolutionary analyses show that Ctri9594 is an antimicrobial peptide in scorpion venom. The mature peptide of Ctri9594 was chemically synthesized with a purity greater than 95% and a molecular mass of 1484.4 Da. Minimum inhibitory concentrations (MICs) indicate that the synthesized mature peptide of Ctri9594 has inhibitory activity against Gram-positive bacteria (Bacillus thuringensis, Bacillus subtilis, Staphylococcus aureus and Micrococcus luteus) but not Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) or a fungus (Candida albicans). The antimicrobial mechanism of Ctri9594 is inferred to be related to its amphiphilic α-helix structure.

BmK NSPK, a Potent Potassium Channel Inhibitor from Scorpion Buthus martensii Karsch, Promotes Neurite Outgrowth via NGF/TrkA Signaling Pathway

Scorpion toxins represent a variety of tools to explore molecular mechanisms and cellular signaling pathways of many biological functions. These toxins are also promising lead compounds for developing treatments for many neurological diseases. In the current study, we purified a new scorpion toxin designated as BmK NSPK (Buthus martensii Karsch neurite-stimulating peptide targeting K_v channels) from the BmK venom. The primary structure was determined using Edman degradation. BmK NSPK directly inhibited outward K⁺ current without affecting sodium channel activities, depolarized membrane, and increased spontaneous calcium oscillation in spinal cord neurons (SCNs) at low nanomolar concentrations. BmK NSPK produced a nonmonotonic increase on the neurite extension that peaked at ~10 nM. Mechanistic studies demonstrated that BmK NSPK increased the release of nerve growth factor (NGF). The tyrosine kinases A (TrkA) receptor inhibitor, GW 441756, eliminated the BmK NSPK-induced neurite outgrowth. BmK NSPK also increased phosphorylation levels of protein kinase B (Akt) that is the downstream regulator of TrkA receptors. These data demonstrate that BmK NSPK is a new voltage-gated potassium (K_v) channel inhibitor that augments neurite extension via NGF/TrkA signaling pathway. K_v channels may represent molecular targets to modulate SCN development and regeneration and to develop the treatments for spinal cord injury.