VLX600 as a drug that is preferentially active against quiescent cells in colon cancer 3-D microtissues.?The anticancer activity is associated with reduced mitochondrial respiration, leading to bioenergetic catastrophe and tumour cell death.?VLX600 shows enhanced cytotoxic activity under conditions of nutrient starvation.?Importantly, VLX600 displays tumour growth inhibition in vivo.