GPR68 Inhibition Induces Ferroptosis in Atypical Teratoid Rhabdoid Tumors.

Abstract

Background: Atypical teratoid/rhabdoid tumors (ATRTs) are aggressive pediatric CNS malignancies with < 30% 5-year survival despite multimodal therapy. No prior studies have explored ferroptosis induction in ATRT.

Aims: To determine whether GPR68 inhibition by ogremorphin (OGM) induces ATF4-dependent ferroptosis in ATRT cell lines and whether SLC7A11 blockade (erastin, ERA) confers similar sensitivity.

Methods: CHLA-02-ATRT and CHLA-06-ATRT cell lines were treated with OGM or ERA. Viability (CellTiter-Glo), GSH levels (GSH-Glo), lipid peroxidation (BODIPY 581/591 C11), and gene expression (qRT-PCR: ATF4, HMOX1, SLC7A11, TFRC) were assessed. Genetic validation used GPR68/ATF4 shRNA, overexpression, and an ATF4 luciferase reporter.

Statistics: Student's t-test with Bonferroni correction (R 4.4.0).

Results: Both cell lines were sensitive to OGM- and ERA-induced ferroptosis, with CHLA-02-ATRT significantly more responsive to OGM than ERA. OGM/ERA depleted GSH, increased lipid peroxidation, and upregulated ATF4, HMOX1, and SLC7A11 mRNA expression. OGM induced TFRC in both cell lines; high-dose ERA upregulated TFRC in CHLA-02-ATRT only. GPR68 knockdown reduced viability, while overexpression or Ogerin increased proliferation. OGM activated ATF4 transcription, and ATF4 overexpression decreased cell survival. ATF4 knockdown rescued OGM-treated cells.

Conclusion: GPR68 inhibition triggers ATF4-dependent ferroptosis in ATRT. SLC7A11 blockade by ERA paralleled the effects of ferroptosis by OGM. These data establish a novel therapeutic strategy with strong translational potential.