Curcumin Induces Ferroptosis in A549 CD133 Cells Through the GSH-GPX4 and FSP1-CoQ10-NAPH Pathways

Background: Cancer stem cells (CSCs) are characterized by an ability for unlimited proliferation and efficiency of self-renewal. The targeting of lung CSCs (LCSCs)-related signaling pathways represent a promising therapeutic strategy for treatment of lung cancer. Ferroptosis a potential strategy for LCSCs treatment, and curcumin cloud induce ferroptosis. In this study, we aimed to observe the effects of curcumin on LCSCs via ferroptosis-related pathways.

Methods: In this study, A549 cluster of differentiation (CD)133 and A549 CD133 cells were isolated using magnetic bead-based separation. Colony formation and sphere formation assays, as well as cells injection in non-obese diabetes/severe combined immune deficiency (NOD/SCID) mice, were used to analyze the tumorigenic ability of cells differentially expressing CD133. A549 CD133 cells were treated with different doses of curcumin (0, 10, 20, 40, 80 μM). Cell viability, glutathione peroxidase 4 (GPX4) and ferroptosis suppressor protein 1 (FSP1) expressions were measured. The 50% inhibitory concentration (IC) of curcumin, two ferroptosis inducers, inhibitor of GPX4 (RSL3) and inhibitor of FSP1 (iFSP1), and a ferroptosis inhibitor, ferrostatin-1 (Fer-1), were used to investigate the mechanism underlying the effect of curcumin on ferroptosis in A549 CD133 cells.

Results: A549 CD133 cells had greater tumorigenic ability than A549 cells. Curcumin treatment suppressed the expressions of GPX4 (glutathione peroxidase 4) and FSP1 in A549 CD133 cells, thereby inducing ferroptosis. RSL3 and iFSP1 respectively suppressed the GSH (glutathione)-GPX4 and FSP1 (ferroptosis suppressor protein 1)-CoQ10 (coenzyme Q10)-nicotinamide adenine dinucleotide (NADH) pathways in A549 CD133 cells. However, the roles of curcumin were blocked by Fer-1 treatment.

Conclusions: In this study, curcumin induced ferroptosis through inhibiting the GSH-GPX4 and FSP1-CoQ10-NADH pathways in A549 CD133 cells, resulting in the inhibition of their self-renewal potential.