Tumor-Induced Hyperlipidemia Contributes to Tumor Growth

• Lipoprotein cholesterol supports tumor growth
• Tumors increase VLDL/LDL levels
• Ces3/TGH deficiency attenuates tumor-induced hyperlipidemia via inhibition of PCSK9
• Tumor growth was suppressed in Ces3/Tgh−/− mice

SummaryThe known link between obesity and cancer suggests an important interaction between the host lipid metabolism and tumorigenesis. Here, we used a syngeneic tumor graft model to demonstrate that tumor development influences the host lipid metabolism. BCR-Abl-transformed precursor B cell tumors induced hyperlipidemia by stimulating very low-density lipoprotein (VLDL) production and blunting VLDL and low-density lipoprotein (LDL) turnover. To assess whether tumor progression was dependent on tumor-induced hyperlipidemia, we utilized the VLDL production-deficient mouse model, carboxylesterase3/triacylglycerol hydrolase (Ces3/TGH) knockout mice. In Ces3/Tgh−/− tumor-bearing mice, plasma triglyceride and cholesterol levels were attenuated. Importantly tumor weight was reduced in Ces3/Tgh−/− mice. Mechanistically, reduced tumor growth in Ces3/Tgh−/− mice was attributed to reversal of tumor-induced PCSK9-mediated degradation of hepatic LDLR and decrease of LDL turnover. Our data demonstrate that tumor-induced hyperlipidemia encompasses a feed-forward loop that reprograms hepatic lipoprotein homeostasis in part by providing LDL cholesterol to support tumor growth.

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