Nuclear Factor Erythroid 2-Related Factor 2 Negatively Regulates Docetaxel-Induced Ferroptosis in Castration-Resistant Prostate Cancer Cells.

Purpose: We explored whether docetaxel (DTX) induced ferroptosis in castration-resistant prostate cancer (CRPC) cells and further investigated its mechanism of action and its regulation of the tumor immune microenvironment.

Materials and methods: First, DTX-induced characteristic changes in the morphology, metabolism and protein expression of CRPC cells as well as electron microscopy ultrastructure were used to verify the occurrence of ferroptosis. Then, through transcriptome sequencing and gene set enrichment analysis, the nuclear factor erythroid 2-related factor 2 (NRF2) gene was screened out according to the differentially expressed genes and their key signaling pathways. Silencing NRF2 (si-NRF2) to explore its regulatory mechanism on DTX-induced ferroptosis in CRPC cells. Finally, TFRC-CAR-T cells combined with DTX were constructed to explore their antitumour ability and immune regulation.

Results: The cell viability of CRPC cells decreased with increasing DTX concentration, and this downwards trend could be partially rescued by ferroptosis inhibitor (ferrostatin-1). Intracellular lipid reactive oxygen species and malondialdehyde levels were significantly increased in DTX-induced CRPC cells, while the levels of glutathione and glutathione peroxidase activity were significantly decreased. Transmission electron microscopy reveals marked mitochondrial shrinkage, spheroidal remodeling, and membrane densification. Transcriptome sequencing and gene set enrichment analysis revealed that the NRF2 gene in the antioxidant stress pathway is primarily involved in regulating ferroptosis. Immunohistochemistry and cytological Western Blot showed DTX chemotherapy activates NRF2 while also up-regulating transferrin receptor (TFRC) in CRPC cells. si-NRF2 gene enhance the sensitivity of DTX-induced ferroptosis in CRPC cells. The killing effect of TFRC-CAR-T cells alone on CRPC cells was weak, while DTX combined with TFRC-CAR-T cells demonstrated stronger killing ability and enhanced cytokine secretion compared to DTX alone.

Conclusions: DTX induces ferroptosis in CRPC cells, a process negatively regulated by NRF2. DTX combined with TFRC-CAR-T cells had a stronger lethal effect to CRPC cells and increase cytokine secretion.