Abstract 5380: Chemotherapy induces a pro-metastatic secretome through cellular senescence

Abstract High grade serous ovarian cancer (HGSOC) is the most lethal gynecological malignancy, with 70-80% of patients having metastatic disease recurrence within 12 months of treatment with first line therapies. A potential factor in HGSOC metastasis and recurrence is chemotherapy induction of cellular senescence, a stable cell cycle arrest which includes a unique secretome (termed the senescence-associated secretory phenotype - SASP) comprised of cytokines, chemokines, small molecules, and differential usage of nutrients. Prior work found that senescent cells can promote tumor progression and metastasis; however, the direct contribution of the SASP to metastatic recurrence has not been deeply explored. Interestingly, we found that the SASP is sufficient to drive increased HGSOC metastatic tumor nodules in vivo. Mechanistically, we found that naïve cancer cells cultured in conditioned media from senescent cells expressed lower levels of multiple extracellular matrix and adhesion related proteins, including fibronectin and integrins. Indeed, the decrease in adhesion factors corresponds to lower cell adhesion and increased cell detachment in 3D conditions. Unexpectedly, experiments depleting SASP proteins suggest a metabolic component of the SASP contributes to the increased metastasis through loss of adhesion factors. We also found that the SASP induced an increase in basal and maximal oxygen consumption, further exhibiting altered metabolism. Using a metabolic CRISPR knockout screen to identify genes required for decreased adhesion after exposure to the SASP, we identified several genes in the electron transport chain, including NDUFA5, a subunit of complex I. Consistently, HGSOC patients with low NDUFA5 expression have upregulated adhesion gene signatures, and NDUFA5 knockdown or pharmacological inhibition of complex I both increase cell adhesion. NDUFA5 is also required for SASP induced increase in basal and maximal respiration. Interestingly, use of scavengers to inhibit ROS did not rescue the adhesion phenotype in NDUFA5 knockout cells, but supplementation with an NAD+ precursor did, implicating NDUFA5’s role as an NADH dehydrogenase in its effect on cell adhesion independent of redox status. Together, our data demonstrate that the chemotherapy-induced SASP has a paracrine effect on mitochondrial metabolism in tumor cells, which in turn decreases cell adhesion. We hypothesize this decrease in adhesion will lead to an increase in tumor metastasis, which contributes to recurrence. Future studies will identify the metabolic composition of SASP that leads to paracrine metabolic reprogramming, the mechanism behind NDUFA5 and respiration’s regulation of adhesion through NAD+ regeneration, and its role in SASP-induced dissemination in vivo. Citation Format: Aidan Robert Cole, Katherine M. Aird. Chemotherapy induces a pro-metastatic secretome through cellular senescence [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 5380.