Metadherin with Stromal‐Immune Cues Drives CD36‐Dependent Lipid Reprogramming and Metastasis in Triple‐Negative Breast Cancer: Insights from a Hetero‐Spheroid Model

ABSTRACT Triple‐negative breast cancer (TNBC) exhibits altered lipid metabolism, driven by the tumor microenvironment's cancer‐associated fibroblasts (CAFs) and tumor‐associated macrophages (TAMs). CD36, a fatty acid translocase, is crucial in this metabolic adaptation of cancer cells. Despite its importance, what controls CD36‐mediated lipid flow is still unclear. This study identifies metadherin (MTDH), an oncogene, as a critical regulator of CD36‐dependent lipid exchange and TNBC progression. Using engineered spheroid models that mimic tumor microenvironment with MTDH‐Wt and MTDHΔ7 overexpressing TNBC cells co‐cultured with CAFs and TAMs, we observed increased lipid uptake, enhanced EMT, and aggressive metastatic features driven by MTDH‐CD36 signaling. Further analyses, including advanced microscopy and transcriptomics, revealed that MTDHΔ7 overexpression in TNBC cells in the presence of stromal‐immune cells, amplifies lipid metabolic pathways, promotes stemness, and pro‐metastatic signaling. Intriguingly, increased formation of tunnelling nanotube‐like structures, indicative of metabolic rewiring, was observed in Lv.MTDHΔ7‐MDA‐MB‐231 CAF‐TAM heterotypic spheroids. These changes were reversed by sulfosuccinimidyl oleate (SSO; CD‐36 inhibitor) treatment. Moreover, SCID mice bearing Lv.MTDH‐Wt/Δ7‐MDA‐MB‐231cells CAF‐TAM heterotypic spheroids led to accelerated breast tumor growth and lipid‐driven metastasis. Importantly, SSO administration significantly reduced lipid accumulation and tumor aggressiveness, confirming CD36 as a functional mediator of MTDH‐driven lipid reprogramming. Our findings establish MTDH as a master regulator of lipid reprogramming through CD36, a process further amplified by CAF‐TAM interactions, which creates a lipid‐rich tumor microenvironment fuelling TNBC aggressiveness. This study reveals crucial mechanistic insights into how stromal‐immune cells induce lipid symbiosis and highlights the MTDH‐CD36 axis as a promising therapeutic target for future combination therapies in aggressive, metabolically reprogrammed TNBC.