Elevated tumor LDLR expression accelerates LDL cholesterol-mediated breast cancer growth in mouse models of hyperlipidemia

Abstract

Obesity is associated with an increase in cancer-specific mortality in women with breast cancer. Elevated cholesterol, particularly low-density lipoprotein cholesterol (LDL-C) is frequently seen in obese women. Here, we aimed to determine the importance of elevated circulating LDL, and LDL receptor (LDLR) expression in tumor cells, on the growth of breast cancer using mouse models of hyperlipidemia. We describe two novel immunodeficient mouse models of hyperlipidemia (Rag1−/−/LDLR−/− and Rag1−/−/ApoE (apolipoprotein E)−/− mice), in addition to established immunocompetent LDLR−/− and ApoE−/− mice. The mice were used to study the effects of elevated LDL-C in human triple negative (MDA-MB-231) and mouse Her2/Neu overexpressing (MCNeuA) breast cancers. Tumors derived from MCNeuA and MDA-MB-231 cells had high LDLR expression and formed larger tumors in mice with high circulating LDL-C concentrations than in mice with lower LDL-C. Silencing the LDLR in the tumor cells led to decreased growth of Her2Neu overexpressing tumors in LDLR−/− and ApoE−/− mice, with increased Caspase 3 cleavage. Additionally, in vitro, silencing the LDLR led to decreased cell survival in serum-starved conditions, associated with Caspase 3 cleavage. Examining publically available human datasets, we found that high LDLR expression in human breast cancers was associated with decreased recurrence-free survival, particularly in patients treated with systemic therapies. Overall, our results highlight the importance of the LDLR in the growth of triple negative and HER2 overexpressing breast cancers in the setting of elevated circulating LDL-C, which may be important contributing factors to the increased recurrence and mortality in obese women with breast cancer.

Lipolysis-stimulated lipoprotein receptor overexpression is a novel predictor of poor clinical prognosis and a potential therapeutic target in gastric cancer

“…Consistent with this, our study revealed that GC cells did not proliferate in a glucose-free medium. However, there are several reports on the association between tumorigenesis and lipid uptake in various types of cancers [ 23 , 24 ]. Hypercholesterolaemia, which is a common metabolic disorder in obese people, has been shown to increase the risk of gastroenterological cancers, and substantial epidemiologic evidence links hypercholesterolaemia to an increased risk of colorectal cancer [ 25 – 29 ].…”

Protein translation associated to PERK arm is a new target for regulation of metainflammation: A connection with hepatocyte cholesterol

“…Under these conditions, the inflammatory phenomenon is induced by adipose tissue and macrophage infiltration that favor the secretion of soluble factors, such as adipokines and extracellular vesicles. In line with this notion, it has been shown that overexpression of LDLR or tumor cells treatment with LDL are associated with an increase in growth and proliferation of mammary cancer cells in vitro and in vivo models …”

microRNAs targeting cellular cholesterol: implications for combating anticancer drug resistance

“…Cells obtain cholesterol from the LDLRs present on the cell surface [109]. High expression of LDLR has been associated with tumours from breast cancer cells in mouse models with hyperlipidemia [110]. Furthermore, knockdown of LDLR was found to reduce tumour growth in these mouse models.…”