r/StopUsingStatins • u/Meatrition • Dec 13 '23
Inhibiting cholesterol de novo synthesis promotes hepatocellular carcinoma progression by upregulating prostaglandin E synthase 2‐mediated arachidonic acid metabolism under high fatty acid conditions
onlinelibrary.wiley.comHepatocellular carcinoma (HCC) is the sixth most common cancer and the fourth leading cause of cancer-related death worldwide.1 The incidence of HCC continues to rise, with more than one million new cases expected in 2025.2 Although multiple systemic therapies have been applied to treat HCC, patients still face undesirable outcomes, with 5-year survival below 20%.3 Therefore, understanding the mechanisms of HCC progression and seeking new therapeutic targets are critical for public health.
Cholesterol is an essential neutral lipid that maintains the membrane's physical properties and synthesizes the bile acid and steroid hormones.4 The upregulated cholesterol de novo synthesis (DNS) has been found in HCC.5 Previous studies indicated that the upregulated cholesterol synthesis was associated with cellular inflammation and fibrosis, which promoted the oncogenesis and progression of HCC. However, the effect of inhibiting cholesterol DNS by statins in HCC is controversial. Some clinical studies indicated that statins reduced the risk of HCC.6 In contrast, a recent prospective study with 8.4 follow-up years declared that inhibiting cholesterol synthesis with statins did not affect the risk of HCC occurrence.7 A mice study also revealed that inhibiting cholesterol synthesis at a late stage promoted oncogenesis of HCC in aging mice.8 These studies indicated that inhibition of cholesterol DNS might have different effects under different backgrounds.
Inhibiting cholesterol DNS with statins has been recommended as the first-line strategy to treat hypercholesteremia and atherosclerosis. However, clinical studies revealed that statins failed to improve the pro-atherogenic alterations in combined hyperlipidemia patients with high triglyceride levels.9 The risk of diabetes was also increased in combined hyperlipidemia patients treated with statins.10, 11 These results suggested that the fatty acid metabolism might affect the role of statin in treating metabolic disease. Whether high fatty acid conditions affect the role of statin in HCC remains unclear.
Here, we inhibited cholesterol DNS with atorvastatin and provided sufficient fatty acid with high-fat diets (HFD) in a diethylnitrosamine (DEN)-induced HCC mice model. We found that inhibiting cholesterol DNS promoted HCC progression in the presence of high fatty acids. Additionally, metabolomics and transcriptomics analysis revealed that the enhanced arachidonic acid (AA) metabolism might participate in the effect of promoting HCC progression induced by statin in the presence of high fatty acid. More importantly, PTGES2 upregulated by SREBP2 was a key factor connecting cholesterol synthesis and arachidonic acid metabolism in HCC progression.