A fluorescence-based assay for the uptake of CPD0801 (DB829) by African trypanosomes

Drug therapies currently used for second stage Human African Trypanosomiasis (HAT) exhibit problems with toxicity, difficulty of administration, and resistance linked to the loss of transporter function. Key to the development of new drugs for HAT is a better understanding of the transport properties of candidate compounds. Standard methods for studying transport utilize radio-labelled permeant or HPLC-MS, however the natural fluorescence of many trypanocidal compounds can be exploited. Here we present a fluorescence-based assay for measuring uptake, by trypanosomes, of CPD0801, a drug candidate for second stage HAT. Sample fluorescence is measured in a 96-well format using a benchtop fluorimeter. Our method is directly applicable to the study of other diamidines with similar fluorescent properties and readily adapted for use with other cell types or fluorescent molecules as we demonstrate for the veterinary trypanocide ethidium.