Abstract 2558: Ferroptosis modulates melanoma progression in an age-specific manner through changes in the tumor microenvironment

Abstract Aging is an independent prognostic factor for melanoma, the most aggressive form of skin cancer. Although immune therapy has shown a dramatic improvement in melanoma treatment, resistance to it still occurs in some patients. Higher oxidative damage in tumor cells and lipid and iron accumulation are singular characteristics of the aged tumor microenvironment (TME). Here, we investigate the impact of these characteristics of the aged TME in promoting ferroptosis, a caspase-independent iron-mediated type of cell death, and as a possible therapeutic opportunity for older patients. Lipid peroxidation levels, resistance to ferroptosis inducers, and the impact of the aged TME secretome were assessed through in vitro and in vivo modeling. Initially, correlation analysis between transcriptomic data (TCGA-SKCM) and ferroptosis sensitivity (CTD^2) was performed to identify common denominators among transcripts associated with the aged TME and ferroptosis pathway. Phenotype-switching markers, such as AXL and Wnt5a, showed a strong correlation with several ferroptosis-related transcripts and an inverse correlation with ferroptosis resistance. Using a panel of melanoma cell lines with distinct Wnt5a levels, we confirmed this association and observed that three critical regulators of lipid peroxidation are downregulated in Wnt5a high lines: GPX4, AIFM2, and GCH1. The comparison through IHC of young and aged mouse skin samples highlighted a pro-ferroptosis signature increasing with age. Senescence markers such as p16 and p21 could be modulated in dermal fibroblasts through induction or inhibition of lipid peroxidation. When associating conditioned media (CM) derived from these dermal fibroblasts (capable of inducing phenotype switching), RSL-3, a GPX4 inhibitor, induced a higher lipid peroxidation and cell death in melanoma cells exposed to aged CM. To understand how ferroptosis impacts tumor growth in young and aged mice, we used a syngeneic tumor model injecting Yumm1.7 cells intra-dermally and the treatment with a lipid peroxidation inducer (imidazole ketone erastin, IKE) or an inhibitor (Liproxstatin-1). Tumors from aged mice showed stronger staining with 4-HNE antibody when compared to young, correlating with AXL and Wnt5a staining. Interestingly, both IKE and Liproxstatin-1 lead to age-specific reduced tumor growth, followed by changes in immune cell populations such as monocytes, macrophages and NK cells. We are currently exploring how these treatments impacted metastatic dissemination, stromal architecture and sensitivity in BRAF/MEK-resistant tumors. These results indicate that ferroptosis modulation is a promising avenue for combined treatment with existing clinical strategies. Citation Format: Murilo Ramos Rocha, Yash Chhabra, Alexis E. Carey, Cheyenne Palm, Kevin Zhang, Edwin Kumah, Vania Wang, Laura Huser, Elizabeth I. Harper, Fan Huang, Ashani Weeraratna. Ferroptosis modulates melanoma progression in an age-specific manner through changes in the tumor microenvironment. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 2558.