Alloimperatorin activates apoptosis, ferroptosis, and oxeiptosis to inhibit the growth and invasion of breast cancer cells in vitro.

Breast cancer is the most common malignant tumour in women. Our research on alloimperatorin from showed that alloimperatorin inhibited breast cancer cell viability in a concentration- and time-dependent manner; it also showed that apoptosis and ferroptosis inhibitors significantly weakened the antisurvival effect of alloimperatorin. Alloimperatorin clearly induced breast cancer cell apoptosis and increased the activities of caspase-3, caspase-8, caspase-9, and poly (ADP-ribose) polymerase; it also caused significant mitochondrial shrinkage, promoted the accumulation of Fe, reactive oxygen species, and malondialdehyde, and significantly reduced mRNA and protein expression levels of SLC7A11 and GPX4, indicating that alloimperatorin induces ferroptosis. In addition, alloimperatorin significantly promoted Kelch-like ECH-associated protein 1 (Keap1) expression; although it did not affect the expression of PGAM5 (mitochondrial serine/threonine protein phosphatase) and apoptosis-inducing factor mitochondria associated 1 (AIFM1), it significantly reduced the phosphorylation level of AIFM1. After downregulating the expression of Keap1, PGAM5, or AIFM1, the inhibitory effect of alloimperatorin on cell viability was significantly weakened, indicating that alloimperatorin regulates the Keap1/PGAM5/AIFM1 pathway to promote oxeiptosis. Alloimperatorin significantly inhibited the invasion of breast cancer cells, while Keap1 siRNA or GPX4 overexpression vectors significantly enhanced cell invasion and effectively reversed the anti-invasive effect of alloimperatorin. Therefore, alloimperatorin induces breast cancer cell apoptosis, ferroptosis, and oxeiptosis, thereby inhibiting cell growth and invasion.