CPT1A facilitated ferroptosis by forming feedback loop with Nrf2 via PI3K/AKT pathway in colorectal cancer

Carnitine palmitoyltransferase 1A (CPT1A) has been implicated in the development of colorectal cancer (CRC), yet its role in ferroptosis remains to be fully understood. In this study, we found that CPT1A expression was associated with metastasis of CRC by gene datasets analysis and immunohistochemical staining of clinical samples, and it was upregulated in CRC cells compared with normal colon cell. The CCK-8, Transwell, and wound healing assays demonstrated that overexpression of CPT1A enhanced the viability, invasion, and migratory capacity of CRC cells. CPT1A expression was reduced following induction of ferroptosis in CRC cells, and this downregulation could be reversed by a ferroptosis inhibitor. Moreover, CPT1A overexpression inhibited ferroptosis in CRC cells. Nrf2, a well-known negative regulator of ferroptosis, was found to colocalize with CPT1A in CRC cells. Molecular docking, Co-IP assay and Ch-IP assay further confirmed an interaction between CPT1A and Nrf2. Notably, Nrf2 overexpression upregulated CPT1A expression, whereas Nrf2 knockdown produced the opposite effect. CPT1A overexpression led to activation of PI3K/AKT pathway in CRC cells. Inactivation of the PI3K/AKT pathway by the inhibitor partially reversed the anti-ferroptosis effect of CPT1A overexpression. Furthermore, inhibition of PI3K/AKT pathway suppressed Nrf2 expression, and reduce nuclear translocation of Nrf2, whereas activation of this pathway enhanced Nrf2 expression and nuclear translocation. In vivo experiments corroborated these findings, showing that CPT1A overexpression promoted Nrf2 expression, suppress ferroptosis, facilitated tumor growth, inactivated PI3K/AKT pathway. Taken together, our data suggest that CPT1A associates with metastasis of CRC, and inhibits ferroptosis through a regulatory feedback loop involving Nrf2 and PI3K/AKT pathway.