Ferroptosis inducer erastin sensitizes NSCLC cells to celastrol through activation of the ROS-mitochondrial fission-mitophagy axis.

Despite recent progress in non-small cell lung cancer (NSCLC) treatment, treatment outcomes remain poor, mainly because of treatment resistance or toxicity. Erastin is a ferroptosis inducer that has shown promising cytotoxic effects in various types of cancers, including NSCLC. Celastrol is a triterpene extracted from the Tripterygium wilfordii that exhibits potential anticancer activity. However, the side effects of celastrol are severe and limit its clinical application. Combination therapy is a promising strategy to overcome the compensatory mechanisms and unwanted off-target effects. In the present study, we found that erastin synergized with celastrol to induce cell death at non-toxic concentrations. The combined treatment with celastrol and erastin significantly increased reactive oxygen species (ROS) generation, disrupted mitochondrial membrane potential, and promoted mitochondrial fission. Furthermore, co-treatment with erastin and celastrol initiated ATG5/ATG7-dependent autophagy, PINK1/Parkin-dependent mitophagy, as well as the expression of heat shock proteins (HSP) in an HSF1-dependent manner. HSF1 knockdown further enhanced cell death in vitro and inhibited tumour growth in vivo. Our findings indicate that the combination of celastrol with erastin may represent a novel therapeutic regimen for patients with NSCLC and warrants further clinical evaluation.