The association of enzymes related to cholesterol esters metabolism with hepatocellular carcinoma

Objectives: The roles of cholesteryl esters (CE) in the pathogenesis of hepatocellular carcinoma (HCC) have not been completely elucidated. This study is aimed to investigate differences in the expression level of enzymes involving in synthesis and degradation of CEs between benign hapatic tissues (BHT) and HCC, and between male and female patients from African American (AA) and Caucasian American (CA). Methods: TMAs were constructed with 97 BHT and 91 HCC samples from patients enrolled in the University of Mississippi Medical Center from 2010 to 2017. Immunochemistry (IHC) was performed on the TMAs for enzymes involved in CE synthesis (acyl CoA:cholesterol acyltransferase 1, ACAT1 and acyl CoA:cholesterol acyltransferase 2, ACAT2), and in CE degradation (lysosomal acid lipase, LAL and neutral cholesterol ester hydrolase 1, NCEH1) following the manufacturer’s instructions. The expression level for each enzyme was expressed as IHC score calculated with a scoring system. Two-tailed Student’s t-test was used to compare the difference in the expression level of each enzyme between two groups. Significant p value was set at p Results: The IHC score of ACAT2 was significantly higher in HCC than in BHT in all population (6.21±2.42 vs (4.89.4±2.40, P=0.0006) and in stratified male population (6.15±2.33 vs 5.08±2.32, p=0.046), but not in stratified women, AA and CA populations. There was no significant difference in IHC score for ACAT1 between HCC and BHT in all population and populations stratified by race and gender. The IHC score of LAL was significantly higher in HCC as compared to BHT in all population (3.57±2.31 vs 2.40±1.30, P =0.0001) and in male population (3.33±2.01 vs 2.39±1.16, p=0.015), but not in stratified women, AA or CA population. The IHC score of NCEH1 was not significantly different between HCC and BHT in all studied population and population stratified by gender. However, it was disparate between AA and CA populations: The IHC score of NCEH1 was significantly lower in HCC than in BHT in AA population (5.59±2.04 vs 6.66±1.74, p=0.031) but it was higher in HCC than in BHT in CA population (6.84±1.96 vs 7.12±1.70, p>0.05). Conclusions: These results suggest that alterations in the expression levels of enzymes involving CE metabolism are associated with pathogenesis, progression and disparities in race and gender of HCC. This study also suggest that ACAT2 predominates CE synthesis as compared to ACAT1, and that LAL plays major role in CE degradation as compared to NCEH1 in association with HCC. Citation Format: Zhirong Liu, Akram Shalaby, Charu Subramony, Jinghe Mao, Xinchun Zhou. The association of enzymes related to cholesterol esters metabolism with hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4378.