Chlorotoxin is a peptide originally isolated from the venom of the scorpion L. quinquestriatus.1,2 It inhibits chloride currents in rat colonic enterocyte plasma membrane preparations when used at a concentration of 594 nM.1 Chlorotoxin also binds to, but does not inhibit, matrix metalloproteinase-2 (MMP-2; IC50s = 0.71 and >30 ?M, respectively), as well as neuropilin-1 (NRP-1; IC50 = 0.78 ?M) in cell-free assays.3 It induces paralysis in crayfish (P. clarkii) but is not cytotoxic to human U87MG glioma, MCF-7 breast cancer, PC3 prostate cancer, and A549 lung cancer cells.1,2 Administration of chimeric antigen receptor (CAR) T cells expressing CAR with chlorotoxin as the targeting domain increase survival and decrease tumor volume in an orthotopic patient-derived xenograft (PDX) mouse model of glioblastoma.4 Liposomes containing chlorotoxin and encapsulating doxorubicin decrease tumor volume in a U87 glioma mouse xenograft model.5 Fluorescently labeled chlorotoxin has been used for tumor imaging in vivo.6
References:
[1]. DeBin, J.A., Maggio, J.E., and Strichartz, G.R.Purification and characterization of chlorotoxin, a chloride channel ligand from the venom of the scorpionAm. J. Physiol.264(2 Pt 1)C361-C369(1993).
[2]. Ayed, A.S., Omran, M.A.A.A., Nabil, Z.I., et al.C-terminal amidation of chlorotoxin does not affect tumour cell proliferation and has no effect on toxin cytotoxicityInt. J. Pept. Res. Ther.27(1)659-667(2021).
[3]. Farkas, S., Cioca, D., Murányi, J., et al.Chlorotoxin binds to both matrix metalloproteinase 2 and neuropilin 1J. Biol. Chem.299(9)104998(2023).
[4]. Wang, D., Starr, R., Chang, W.C., et al.Chlorotoxin-directed CAR T cells for specific and effective targeting of glioblastomaSci. Transl. Med.12(533)eaaw2672(2020).
[5]. Xiang, Y., Liang, L., Wang, X., et al.Chloride channel-mediated brain glioma targeting of chlorotoxin-modified doxorubicine-loaded liposomesJ. Control Release152(3)402-410(2011).
[6]. Veiseh, M., Gabikian, P., Bahrami, S.B., et al.Tumor paint: A chlorotoxin:Cy.
[5]. 5 bioconjugate for intraoperative visualization of cancer fociCancer Res.67(14)6882-6888(2007).
















