Peroxiredoxin 1 knockdown sensitizes cancer cells to reactive oxygen species-generating drugs - an alternative approach for chemotherapy.

Peroxiredoxins have multiple cellular functions as major antioxidants, signaling regulators and tumor suppressors. Peroxiredoxin 1 (PRX1) is the most abundant among the six isoforms of human peroxiredoxins, catalyzing the reduction of peroxides utilizing thioredoxin 1as an electron donor. PRX1 is frequently over-expressed in various cancer cells, which is thought to be associated with carcinogenesis, metastasis and resistance to radiotherapy or chemotherapy. We investigated how modulations of intracellular redox system, especially PRX1, affect cancer cell sensitivity to reactive oxygen species (ROS)-generating drugs. We observed that stable and transient Prx1 knockdown (Prx1-) significantly enhances HeLa cell sensitivity to β-lapachone (β-lap), a potential anticancer agent, and to other ROS-generating molecules. ROS accumulation played a crucial role in drug-enhanced Prx1- cell death. For β-lap, Prx1- cells sensitization is achieved through combined action of accumulation of ROS and enhancement of mitogen-activated protein kinase pathway activation. The effect of other ROS-inducing drugs on Prx1- cell survival will also be presented and discussed. Taken together, our data provide evidence that PRX1 could be an interesting anticancer target and modulation of intracellular redox states through PRX1 inhibition could be an alternative approach to enhance cancer cell sensitivity to ROS-generating drugs.