Phlogiellus bundokalbo spider venom: Its neuroactive, phospholipase a2 and cytotoxic components against human breast adenocarcinoma (MCF-7)

@#Spider venoms and toxins are valuable sources of lead compounds for drug development due to their essential role in cellular and physiological processes targeting various receptors. Here, we present the protein profile of the venom of Phlogiellus bundokalbo, an endemic Philippine tarantula, to screen and characterize its cytotoxicity against MCF-7 cells, secretory phospholipase a2 (sPLA2), and neurotoxicity to evaluate its potential anticancer properties. Spider venom was extracted via electrical stimulation. Venom components were fractionated by reversed-phase high-performance liquid chromatography and characterized through liquid chromatography-mass spectrometry (LC-MS) and SDS-PAGE analysis before assay. The resulting five venom fractions were amphiphilic peptides showing cytotoxicity against MCF-7 cells in a concentrationdependent manner (IC50 ranging from 52.25μg/ml to 110.20μg/ml) after 24-hour incubation. Cells appeared detached, rounded, and shrunk with cytoplasmic condensation upon overnight incubation with venom fractions. The sPLA2 was observed in all the venom fractions tested for cytotoxicity. Venom fractions revealed a predominant mass of ~3-5 kDa with LC-MS analysis. Results showed distinct similar mass as μ- theraphotoxin-Phlo1a, an Australian tarantula, Phlogiellus sp. toxin with inhibitor cystine knot motif. The venom fractions exhibit excitatory neurotoxins that might activate presynaptic voltage-gated ion channels, such as an agonist or gating modifier toxins that slow down the channel inactivation similar to spider toxins. In conclusion, the spider venom of P. bundokalbo exhibits cytotoxic, phospholipase A2, and neuroactive properties suggesting that its venom components, upon further purification and structure-function analysis, can be potential tools in the development of targeted breast chemotherapeutics.

Neuroactive venom compounds obtained from Phlogiellus bundokalbo as potential leads for neurodegenerative diseases: insights on their acetylcholinesterase and beta-secretase inhibitory activities in vitro

Spider venom is a rich cocktail of neuroactive compounds designed to prey capture and defense against predators that act on neuronal membrane proteins, in particular, acetylcholinesterases (AChE) that regulate synaptic transmission through acetylcholine (ACh) hydrolysis - an excitatory neurotransmitter - and beta-secretases (BACE) that primarily cleave amyloid precursor proteins (APP), which are, in turn, relevant in the structural integrity of neurons. The present study provides preliminary evidence on the therapeutic potential of Phlogiellus bundokalbo venom against neurodegenerative diseases. Methods Spider venom was extracted by electrostimulation and fractionated by reverse-phase high-performance liquid chromatography (RP-HPLC) and characterized by matrix-assisted laser desorption ionization-time flight mass spectrometry (MALDI-TOF-MS). Neuroactivity of the whole venom was observed by a neurobehavioral response from Terebrio molitor larvae in vivo and fractions were screened for their inhibitory activities against AChE and BACE in vitro. Results The whole venom from P. bundokalbo demonstrated neuroactivity by inducing excitatory movements from T. molitor for 15 min. Sixteen fractions collected produced diverse mass fragments from MALDI-TOF-MS ranging from 900-4500 Da. Eleven of sixteen fractions demonstrated AChE inhibitory activities with 14.34% (± 2.60e-4) to 62.05% (± 6.40e-5) compared with donepezil which has 86.34% (± 3.90e-5) inhibition (p > 0.05), while none of the fractions were observed to exhibit BACE inhibition. Furthermore, three potent fractions against AChE, F1, F3, and F16 displayed competitive and uncompetitive inhibitions compared to donepezil as the positive control. Conclusion The venom of P. bundokalbo contains compounds that demonstrate neuroactivity and anti-AChE activities in vitro, which could comprise possible therapeutic leads for the development of cholinergic compounds against neurological diseases.(AU)

Phlogiellus bundokalbo spider venom: cytotoxic fractions against human lung adenocarcinoma (A549) cells

Spider venom is a potential source of pharmacologically important compounds. Previous studies on spider venoms reported the presence of bioactive molecules that possess cell-modulating activities. Despite these claims, sparse scientific evidence is available on the cytotoxic mechanisms in relation to the components of the spider venom. In this study, we aimed to determine the cytotoxic fractions of the spider venom extracted from Phlogiellus bundokalbo and to ascertain the possible mechanism of toxicity towards human lung adenocarcinoma (A549) cells. Methods: Spider venom was extracted by electrostimulation. Components of the extracted venom were separated by reversed-phase high performance liquid chromatography (RP-HPLC) using a linear gradient of 0.1% trifluoroacetic acid (TFA) in water and 0.1% TFA in 95% acetonitrile (ACN). Cytotoxic activity was evaluated by the MTT assay. Apoptotic or necrotic cell death was assessed by microscopic evaluation in the presence of Hoechst 33342 and Annexin V, Alexa FluorTM 488 conjugate fluorescent stains, and caspase activation assay. Phospholipase A2 (PLA2) activity of the cytotoxic fractions were also measured. Results: We observed and isolated six fractions from the venom of P. bundokalbo collected from Aurora, Zamboanga del Sur. Four of these fractions displayed cytotoxic activities. Fractions AT5-1, AT5-3, and AT5-4 were found to be apoptotic while AT5-6, the least polar among the cytotoxic components, was observed to induce necrosis. PLA2 activity also showed cytotoxicity in all fractions but presented no relationship between specific activity of PLA2 and cytotoxicity. Conclusion: The venom of P. bundokalbo spider, an endemic tarantula species in the Philippines, contains components that were able to induce either apoptosis or necrosis in A549 cells.(AU)