Lysosome-Targeted Squaramide Anion Transporters.

Targeting anion transporters to specific organelles has previously been shown to be an effective strategy to enhance their cytotoxicities against cancerous cell lines. In this work a new family of squaramide anion transporters appended with two different lysosome targeting groups via a 1,4-substituted benzene spacer were synthesised. Cell viability studies showed that the transporters containing the N,N-dimethylamine targeting group exhibited the greatest cytotoxic effects despite possessing lower transport activities than the non-targeted control compounds and those containing the morpholine targeting group. Subcellular localisation studies using anthracene-labelled squaramides found that both targeting motifs successfully directed compounds to the lysosome, but the morpholine-containing motif accumulated to a lesser extent.