Filipa Sofia Carvalho

Most cancer-related deaths are due to metastases. Systemic factors, such as lipid-enriched environments [as low-density lipoprotein (LDL)-cholesterol], favor breast cancer, including triple-negative breast cancer (TNBC) metastasis formation. Mitochondria metabolism impacts TNBC invasive behavior but its involvement in a lipid-enriched setting is undisclosed. Here we show that LDL increases lipid droplets, induces CD36 and augments TNBC cells migration and invasion in vivo and in vitro. LDL induces higher mitochondrial mass and network spread in migrating cells, in an actin remodeling-dependent manner, and transcriptomic and energetic analyses revealed that LDL renders TNBC cells dependent on fatty acids (FA) usage for mitochondrial respiration. Indeed, engagement on FA transport into the mitochondria is required for LDL-induced migration and mitochondrial remodeling. Mechanistically, LDL treatment leads to mitochondrial long-chain fatty acid accumulation and increased reactive oxygen species (ROS) production. Importantly, CD36 or ROS blockade abolished LDL-induced cell migration and mitochondria metabolic adaptations. Our data suggest that LDL induces TNBC cells migration by reprogramming mitochondrial metabolism, revealing a new vulnerability in metastatic breast cancer.Significance:LDL induces breast cancer cell migration that relies on CD36 for mitochondrial metabolism and network remodeling, providing an antimetastatic metabolic strategy.

List of primers used for measurements of gene expression levels and mtDNA content by quantitative real-time PCR.

LDL exposure induces mitochondrial network spread distribution and destabilized cristae in migrating breast cancer cells. Related to Fig. 2

LDL-exposed breast cancer cells show differential invasion potential and metastatic tropism to distant sites in xenotransplanted zebrafish larvae at 4dpi (6dpf). Related to Fig. 1.

LDL exposure induces mitochondrial network spread distribution and destabilized cristae in migrating breast cancer cells. Related to Fig. 2

Fatty acid profile in relative content (%). Qualitative analysis was calculated by dividing each raw area by the sum of total raw areas. Dash (‘-‘) represents lipid species that were not identified in the sample. Legend: CTR (control), ETO (etomoxir, 100 µM).

Uncropped membranes relative to the western blot for Drp1, Mfn1, Mfn2 and b-ACTIN proteins displayed in Fig. 2J

LDL-exposed breast cancer cells show differential invasion potential and metastatic tropism to distant sites in xenotransplanted zebrafish larvae at 4dpi (6dpf). Related to Fig. 1.

LDL-induced migratory behavior of TNBC cells relies on fatty acid transport into the mitochondria. Related to Fig. 5

Lipid exposure induces metabolic and bioenergetic dependencies in breast cancer cells. Related to Fig. 4