Identification of a cytotoxic peptide from the spider Enoploctenus cyclothorax venom on leukemia cell lineages

BackgroundChronic myeloid leukemia and acute lymphoblastic leukemia are significant malignancies requiring novel therapeutic agents. This study aimed to identify cytotoxic components of the venom of the spider Enoploctenus cyclothorax against K562 and NALM-6 cell lines. MethodsVenom was extracted, lyophilizated and incubated with cultured K562 and NALM-6 cells at concentrations ranging from 0.1 to 100 {micro}g/mL for 24 and 48 hours. MTT assay for cell viability was assessed to measure cytotoxicity. Venom fractionation started with centrifugation on AMICON(R) filters in a cutting edge of 10 kDa which separates low-(LW) and high-molecular weight (HW) fractions. The active fraction was fractionated using reversed-phase HPLC and the most active compound was purified and analyzed via mass spectrometry to determine its molecular weight. ResultsCytotoxic activity was observed in both cell lines at concentrations of 10, 30, and 100 {micro}g/mL E. cyclothorax. The centrifugation revealed that antineoplastic activity was concentrated in HW fraction. Subsequent chromatography isolated fraction F7 (specifically F7c) as the most potent. Mass spectrometry characterized F7c as a mild hydrophobic polypeptide with a molecular mass of approximately 6270 Da. ConclusionA polypeptide of approximately 6270 Da isolated from E. cyclothorax venom demonstrates significant in vitro cytotoxic properties against leukemic lineages. Further sequencing and synthesis are required to advance the pharmacological bioprospecting of this potential antineoplastic agent.