Biological Activity
Chlorotoxin is a 36 amino-acid peptide from the venom of the Israeli scorpion Leiurus quinquestriatus with anticancer activity. Chlorotoxin is a chloride channel blocker.
In Vitro
Chlorotoxin (Chlorotoxin) preferentially binds to tumor cells and has been harnessed to develop an imaging agent to help visualize tumors during surgical resection. In addition, chlorotoxin has potential as a vehicle to deliver anti-cancer drugs specifically to cancer cells. Chlorotoxin is shown to bind glioma cells, but is unable to bind normal rat astrocytes and Te671, a human rhabdomyosarcoma cell line. Chlorotoxin inhibits the migration of U251MG (glioma) cells, with an IC50 of 600 nM[2]. Chlorotoxin binds to glioma cells is specific and involves high affinity (Kd=4.2 nM) and low affinity (Kd=660 nM) binding sites[3].Small conductance chloride channels are shown to be potently blocked by Chlorotoxin. Chlorotoxin has been used as a general pharmacological tool to investigate the function of chloride channels[4].
In Vivo
Chlorotoxin shows insecticidal activity on insects and other invertebrates. After the administration of I-Chlorotoxin to tumor-bearing mice, the peptides accumulated within the tumor[2].Chlorotoxin selectively accumulates in the brain of tumor-bearing mice with calculated brain: muscle ratios of 36.4% of injected dose/g (ID/g), as compared to 12.4%ID/g in control animals[3].
Target
Chloride Channel[1]
Animal Administration
Mouse: At 24, 48, 72, and 96 h after tumor-bearing and control SCID mice are injected with 125l-labeled Chlorotoxin, they are anesthetized and imaged. Both 125I- and 131l-labeled Chlorotoxin-injected animals and their control counterparts are killed at indicated time points for biodistribution studies[3].
References & source
[1]. DeBin JA, et al. Purification and characterization of chlorotoxin, a chloride channel ligand from the venom of the scorpion. Am J Physiol. 1993 Feb;264(2 Pt 1):C361-9.
[2]. Ojeda PG, et al. Chlorotoxin: Structure, activity, and potential uses in cancer therapy. Biopolymers. 2016 Jan;106(1):25-36.
[3]. Soroceanu L, et al. Use of chlorotoxin for targeting of primary brain tumors. Cancer Res. 1998 Nov 1;58(21):4871-9.
[4]. Dardevet L, et al. Chlorotoxin: a helpful natural scorpion peptide to diagnose glioma and fight tumor invasion. Toxins (Basel). 2015 Mar 27;7(4):1079-101.
Published experimental findings depend on the model and assay conditions. They do not guarantee equivalent performance in every application. For laboratory research use only.
