Cancer cell injury by cytotoxins from cobra venom is mediated through lysosomal damage.
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ABSTRACT:
SUBMITTER: Feofanov AV
PROVIDER: S-EPMC1184559 | biostudies-other | 2005 Aug
REPOSITORIES: biostudies-other
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Project description:Currently, there is an increasing amount of evidence indicating that exosomes and the miRNAs they contain are crucial players in various biological processes. However, the role of exosomes and miRNAs in snake venom during the envenomation process remains largely unknown. In this study, fresh venom from Naja atra of different ages (2-month-old, 1-year-old, and 5-year-old) was collected, and exosomes were isolated through ultracentrifugation. The study found that exosomes with inactivated proteins and enzymes can still cause symptoms similar to cobra envenomation, indicating that substances other than proteins and enzymes in exosomes may also play an essential role in cobra envenomation. Furthermore, the expression profiles of isolated exosome miRNAs were analyzed. The study showed that a large number of miRNAs were co-expressed and abundant in cobra venom exosomes (CV-exosomes) of different ages, including miR-2904, which had high expression abundance and specific sequences. The specific miR-2094 derived from CV-exosomes (CV-exo-miR-2904) was overexpressed both in vitro and in vivo. As a result, CV-exo-miR-2904 induced symptoms similar to cobra envenomation in mice and caused liver damage, demonstrating that it plays a crucial role in cobra envenomation. These results reveal that CV-exosomes and the miRNAs they contain play a significant regulatory role in cobra envenomation. Our findings provide new insights for the treatment of cobra bites and the development of snake venom-based medicines.
| S-EPMC10544165 | biostudies-literature
Project description:Inadequate effectiveness of Indian antivenoms in treating envenomation caused by the Spectacled Cobra/Indian Cobra (Naja naja) in Sri Lanka has been attributed to geographical variations in the venom composition. This study investigated the de novo venom-gland transcriptomics and venom proteomics of the Sri Lankan N. naja (NN-SL) to elucidate its toxin gene diversity and venom variability. The neutralization efficacy of a commonly used Indian antivenom product in Sri Lanka was examined against the lethality induced by NN-SL venom in mice. The transcriptomic study revealed high expression of 22 toxin genes families in NN-SL, constituting 46.55% of total transcript abundance. Three-finger toxins (3FTX) were the most diversely and abundantly expressed (87.54% of toxin gene expression), consistent with the dominance of 3FTX in the venom proteome (72.19% of total venom proteins). The 3FTX were predominantly S-type cytotoxins/cardiotoxins (CTX) and α-neurotoxins of long-chain or short-chain subtypes (α-NTX). CTX and α-NTX are implicated in local tissue necrosis and fatal neuromuscular paralysis, respectively, in envenomation caused by NN-SL. Intra-species variations in the toxin gene sequences and expression levels were apparent between NN-SL and other geographical specimens of N. naja, suggesting potential antigenic diversity that impacts antivenom effectiveness. This was demonstrated by limited potency (0.74 mg venom/ml antivenom) of the Indian polyvalent antivenom (VPAV) in neutralizing the NN-SL venom. A pan-regional antivenom with improved efficacy to treat N. naja envenomation is needed.
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Project description:Arteriogenesis, the growth of natural bypass blood vessels, can compensate for the loss of arteries caused by vascular occlusive diseases. Accordingly, it is a major goal to identify the drugs promoting this innate immune system-driven process in patients aiming to save their tissues and life. Here, we studied the impact of the Cobra venom factor (CVF), which is a C3-like complement-activating protein that induces depletion of the complement in the circulation in a murine hind limb model of arteriogenesis. Arteriogenesis was induced in C57BL/6J mice by femoral artery ligation (FAL). The administration of a single dose of CVF (12.5 µg) 24 h prior to FAL significantly enhanced the perfusion recovery 7 days after FAL, as shown by Laser Doppler imaging. Immunofluorescence analyses demonstrated an elevated number of proliferating (BrdU+) vascular cells, along with an increased luminal diameter of the grown collateral vessels. Flow cytometric analyses of the blood samples isolated 3 h after FAL revealed an elevated number of neutrophils and platelet-neutrophil aggregates. Giemsa stains displayed augmented mast cell recruitment and activation in the perivascular space of the growing collaterals 8 h after FAL. Seven days after FAL, we found more CD68+/MRC-1+ M2-like polarized pro-arteriogenic macrophages around growing collaterals. These data indicate that a single dose of CVF boosts arteriogenesis by catalyzing the innate immune reactions, relevant for collateral vessel growth.
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Project description:Breast cancer is the most common cancer which causes significant morbidity and mortality among women worldwide. Lack of medical facilities for early detection, therapeutic strategies for treatment and side effects due to pharmacological compounds have encompassed the need for new therapies mostly from natural sources. A lot of components have been identified from different snake venoms as therapeutic agents. A group of polypeptides (60-70 amino acid residues) called cytotoxins or cardiotoxins present in an elapid family of snakes have a wide variety of pharmaceutical actions and have the tendency to damage a wide variety of cells including cancerous cells. The aim of the present study was to evaluate the cytotoxic effect of NN-32 protein toxin purified from Indian Spectacled Cobra venom against human breast cancer cell lines (MCF-7 and MDA-MB-231).The NN-32 toxin was purified by ion exchange chromatography and further by RP-HPLC. The potential anticancer effects of the NN-32 toxin on MCF-7 and MDA-MB-231 cells were evaluated using MTT, anti-proliferation, neutral red (NR) uptake and Lactate Dehydrogenase (LDH) release assay.The ion exchange chromatography showed various peaks among fraction no. 35 showing cytotoxic activity and this fraction showed a single peak with retention time 3.6 mins by HPLC using C18 column. The NN-32 toxin induced cytotoxicity in MCF-7 and MDA-MB-231 cells with the IC50 value of 2.5 and 6.7 ?g/ml respectively. The NN-32 showed significant cytotoxicity to both the cell lines along with low cytotoxicity to MCF-10A (normal breast epithelial) cells. The cytotoxic effect was further confirmed by the anti-proliferative, NR uptake and LDH release assays.The purified toxin NN-32 from Naja naja venom showed cytotoxic activity against MCF-7 (ER+) and MDA-MB-231(ER-) cells in both dose dependent and time dependent manner.
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Project description:BackgroundThe king cobra (Ophiophagus hannah) is widely distributed throughout many parts of Asia. This study aims to investigate the complexity of Malaysian Ophiophagus hannah (MOh) venom for a better understanding of king cobra venom variation and its envenoming pathophysiology. The venom gland transcriptome was investigated using the Illumina HiSeq™ platform, while the venom proteome was profiled by 1D-SDS-PAGE-nano-ESI-LCMS/MS.ResultsTranscriptomic results reveal high redundancy of toxin transcripts (3357.36 FPKM/transcript) despite small cluster numbers, implying gene duplication and diversification within restricted protein families. Among the 23 toxin families identified, three-finger toxins (3FTxs) and snake-venom metalloproteases (SVMPs) have the most diverse isoforms. These 2 toxin families are also the most abundantly transcribed, followed in descending order by phospholipases A2 (PLA2s), cysteine-rich secretory proteins (CRISPs), Kunitz-type inhibitors (KUNs), and L-amino acid oxidases (LAAOs). Seventeen toxin families exhibited low mRNA expression, including hyaluronidase, DPP-IV and 5'-nucleotidase that were not previously reported in the venom-gland transcriptome of a Balinese O. hannah. On the other hand, the MOh proteome includes 3FTxs, the most abundantly expressed proteins in the venom (43 % toxin sbundance). Within this toxin family, there are 6 long-chain, 5 short-chain and 2 non-conventional 3FTx. Neurotoxins comprise the major 3FTxs in the MOh venom, consistent with rapid neuromuscular paralysis reported in systemic envenoming. The presence of toxic enzymes such as LAAOs, SVMPs and PLA2 would explain tissue inflammation and necrotising destruction in local envenoming. Dissimilarities in the subtypes and sequences between the neurotoxins of MOh and Naja kaouthia (monocled cobra) are in agreement with the poor cross-neutralization activity of N. kaouthia antivenom used against MOh venom. Besides, the presence of cobra venom factor, nerve growth factors, phosphodiesterase, 5'-nucleotidase, and DPP-IV in the venom proteome suggests its probable hypotensive action in subduing prey.ConclusionThis study reports the diversity and abundance of toxins in the venom of the Malaysian king cobra (MOh). The results correlate with the pathophysiological actions of MOh venom, and dispute the use of Naja cobra antivenoms to treat MOh envenomation. The findings also provide a deeper insight into venom variations due to geography, which is crucial for the development of a useful pan-regional antivenom.
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Project description:Cobra venom factor (CVF) is the complement-activating protein in cobra venom. Like C3b, CVF forms with factor B and factor D in human and mammalian serum the bimolecular C3/C5 convertase. This functional similarity of CVF and C3 correlates with many structural similarities, which led to the suggestion that CVF is evolutionally related to C3. We report here the molecular cloning and derived primary structure of CVF. CVF mRNA is > 5924 nucleotides in length. It contains a single open reading frame of 4926 nucleotides, coding for a pre-pro-protein of 1642 amino acids. The deduced amino acid sequence reveals approximately 70% protein similarity to mammalian and human C3 and exceeds 91% in the case of cobra C3. The single-chain pre-pro-CVF consists of a 22-amino acid signal sequence, a 627-amino acid alpha-chain, and a 989-amino acid precursor chain for the CVF gamma- and beta-chains. The processing of pro-CVF involves the removal of 4 arginine residues between the alpha- and precursor chains as well as of the C3a-like and C3d-like domains from the precursor chain, thereby confirming the predicted chain homologies to C3. Pro-CVF contains five potential N-glycosylation sites, of which only three can be expected to be glycosylated in mature CVF. Like C3, pro-CVF contains 27 cysteine residues and a homologous thioester site in the C3d-like region.
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Project description:FOLFIRINOX, a combination of chemotherapy drugs (Fluorouracil, Oxaliplatin, Irinotecan -FOI), provides the best clinical benefit in pancreatic ductal adenocarcinoma (PDAC) patients. In this study we explore the role of miRNAs (MIR) as modulators of chemosensitivity to identify potential biomarkers of response. We find that 41 and 84 microRNA inhibitors enhance the sensitivity of Capan1 and MiaPaCa2 PDAC cells respectively. These include a MIR1307-inhibitor that we validate in further PDAC cell lines. Chemotherapy-induced apoptosis and DNA damage accumulation are higher in MIR1307 knock-out (MIR1307KO) versus control PDAC cells, while re-expression of MIR1307 in MIR1307KO cells rescues these effects. We identify binding of MIR1307 to CLIC5 mRNA through covalent ligation of endogenous Argonaute-bound RNAs cross-linking immunoprecipitation assay. We validate these findings in an in vivo model with MIR1307 disruption. In a pilot cohort of PDAC patients undergoing FOLFIRONX chemotherapy, circulating MIR1307 correlates with clinical outcome.
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