TFCP2L1 promotes GPX4-mediated ferroptosis to inhibit breast cancer cell proliferation and metastasis via the PI3K/AKT signaling pathway

Breast cancer represents the most prevalent form of malignant tumors among women. Despite the existence of numerous therapeutic methods, a significant portion of patients face a poor prognosis, highlighting the urgency in identifying new remedial targets. Here, we for the first time demonstrated that the CP2 family member TFCP2L1, a classical marker of embryonic stem cell maintenance, as a tumor suppressor in breast cancer. Patients with breast cancer have poorer prognoses when TFCP2L1 is expressed highly. Consistently, the expression of TFCP2L1 is higher in normal breast cells than those in breast cancer cell lines. Gain- and loss-of-function and xenograft tumor assay showed that overexpression of TFCP2L1 significantly inhibited both the proliferation and migration of breast cancer cells in vivo and in vitro. Conversely, the knockdown of TFCP2L1 promoted the proliferation and migration of breast cancer cells. Mechanistically, we found that TFCP2L1 suppresses breast cancer progression by directly inhibiting the expression of glutathione peroxidase 4 (GPX4), a key regulator of ferroptosis. Therefore, inhibition of GPX4 by RSL3, an inducer of ferroptosis was able to promote the function of TFCP2L1 in breast cancer cells. On the other hand, transcriptome high-throughput exhibited that TFCP2L1 negatively regulated the activity of PI3K/AKT signaling pathway. Administration of SC79, an AKT activator, was capable of partially restoring the negative effects of TFCP2L1 on GPX4 transcription. Together, TFCP2L1 functions by directly or indirectly regulating GPX4-mediated ferroptosis, and may serve as a novel biomarker and potential therapeutic target for breast cancer.