Glutamine Starvation Induces Ferroptosis in NSCLC via AMPK/PDZD8-Mediated Ferritinophagy

Objectives: The dependence of non-small cell lung cancer (NSCLC) on glutamine has made targeting glutamine metabolism an attractive therapeutic approach. Dietary interventions are increasingly considered as adjuvant cancer therapies. This study aims to explore the relationship between glutamine starvation and ferroptosis in NSCLC and to elucidate the underlying molecular mechanisms. Methods: The effects of glutamine starvation were evaluated both in A549 and H460 NSCLC cell lines and in vivo using xenograft models in SCID mice. Assessments included cell viability, migration, clonogenic capacity, and the expression of key proteins. To gain mechanistic insight, AMPK was either overexpressed or inhibited, and key markers of ferritinophagy (including ULK1, BECN1, NCOA4, and LC3-II/I) and ferroptosis (such as ACSL4, GPX4, and xCT) were analyzed. Results: Glutamine starvation markedly suppressed tumor growth in both in vitro and in vivo settings, while also reducing cell migration and clonogenicity in cultured cells. This intervention activated AMPK, as indicated by increases in both total and phosphorylated forms, and upregulated PDZD8 expression. Mechanistically, AMPK activation played a critical role in driving ferritinophagy and ferroptosis—manipulation of AMPK consistently altered key markers of these processes. Furthermore, AMPK levels influenced PDZD8 protein expression. Notably, overexpressing PDZD8 alone was sufficient in promoting both ferritinophagy and ferroptosis, indicating that PDZD8 acts as a critical downstream mediator of AMPK in this pathway. Conclusions: Our findings reveal that glutamine starvation triggers ferroptosis in NSCLC via activation of ferritinophagy, mediated by the AMPK/PDZD8 signaling pathway. These results support the potential of dietary glutamine restriction as a novel therapeutic approach for NSCLC.