ABSTRACT
@#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.