SARs of a new type of s-triazine derivatives targeting vimentin to induce methuotic phenotype

Abstract Methuosis is a form of non-apoptotic cell death associated with massive cytoplasmic vacuolization [1]. While cells during methuosis manifest a perturbed micropinocytosis, the underlying protein targets remain unclear [2]. Herein, we describe the design, synthesis and structure−activity relationships of a series of novel s-triazine compounds, which can induce methuotic phenotype in various types of cancer cells. The compound V6, i.e., (E)-1-(4-chlorophenyl)-3-(4-((4-morpholino-6-styryl-1,3,5-triazine-2-yl)amino)phenyl)urea, exhibited a striking methuotic phenotype with a minimal effective concentration of less than 10 nM in U87 glioblastoma cells. Based on the structure−activity relationships studies, we designed and synthesized an active probe P1 that retained the full potential of V6 in inducing the methuotic phenotype in U87 glioblastoma cells. Using this probe following affinity-based proteomic profiling strategy, we identified vimentin as the specific target protein of the compound V6. Molecular docking revealed that V6 can form hydrogen bonds with vimentin at 273R and 276Y in its rod domain. These results indicate that this novel s-triazine analogue induced cancer cells methuotic phenotype through targeting vimentin. Since micropinocytosis is hijacked by cancer cells as an important route of nutrient uptake [3–5] and because vimentin, as a canonical marker of the epithelial-to-mesenchymal transition, is involved in cancer progression and metastasis [6–8], our study not only created a powful tool that enables a further characterization of methuotic process [9-11], but also provide a rationale and an avenue for the pharmacological targeting of vimentin and of macropinocytotic machinery to treat cancer.