Cholesterol and Radiosensitivity

Although there is some evidence in animal studies that cholesterol signaling mediates radiation sensitivity of normal tissues, until recently, no connection had been made between cholesterol signaling and tumor radiosensitivity. Aberrant cholesterol signaling in breast cancer promotes oncogenesis and tumor progression by either altering membrane fluidity, membrane associated rafts, or as a direct activator of transcription. Cholesterol is synthesized de novo by the mevalonate pathway. A causal role for hydroxy-3-methylglutaryl-coenzyme A reductase, a rate-limiting enzyme of the mevalonate pathway, in oncogenic transformation, progression, and sensitivity to treatment offers an opportunity for drugs that inhibit this enzyme (i.e., statins) as well as other cholesterol mediating strategies as radiosensitizing treatments. This review discusses potential mechanisms by which statins alter cholesterol signaling in breast cancer and potentially enhances radiation sensitivity and outcome with a special focus on inflammatory breast cancer.