Transcriptional analysis of the expression and prognostic value of lipid droplet-localized proteins in hepatocellular carcinoma

The accumulation of lipid droplets (LDs) in hepatocytes is the main pathogenesis in nonalcoholic fatty liver disease (NAFLD), which is also the key risk factor for the progression of hepatocellular carcinoma (HCC). LDs behaviors are demonstrated to be associated with HCC advancement, and are tightly regulated by a subset protein localized on the surface of LDs. However, the role of LDs-localized protein in HCC has been rarely investigated. This study is focused on the transcriptional dynamic and prognostic value of LDs-localized protein in HCC. Firstly, we summarized the known LDs-localized proteins, which are demonstrated by immunofluorescence according to previous studies. Next, by the use of GEPIA/UALCAN/The Human Protein Atlas databases, we screened the transcriptional change in tumor and normal liver tissues, and found that 13 LDs-localized proteins may involve in the progression of HCC. Then we verified the transcriptional changes of 13 LDs-localized proteins by the use of HCC samples. Moreover, based on the assays of fatty liver of mice and human NAFLD liver samples, we found that the hepatic steatosis mainly contributed to the transcriptional change of selected LDs-localized proteins, indicating the involvement of these LDs-localized proteins in the negative role of NAFLD in HCC progression. Finally, we focused on the role of PLIN3 in HCC, and revealed that NAFLD status significantly promoted PLIN3 transcription in HCC tissue. Functional studies revealed that PLIN3 knockdown significantly limited the migration and chemosensitivity of hepatoma cells, suggesting the positive role of PLIN3 in HCC progression. Our study not only revealed the transcriptional change and prognostic value of lipid droplet-localized proteins in HCC, but also built the correlation between HCC and hepatic steatosis. Overall design: Total of 6 six-week old C57BL/6 mice were randomly divided into control and experimental groups (3 per group) treated with CSAA (Dyets, 518754, USA) and CDAA (Dyets, 518753, USA) feed respectively. After one week acclimatization, the experimental group was to be fed with the transitional feed for one week. During this transitional stage, the CSAA and CDSS feeds were mixed at 2:1 on the first three days, 1:1 on the fourth to fifth days, 1:2 on the sixth to seventh days, and CDAA feed was completely added after this period. At the 6th week after transitional feeding, the animals of each group were sampled. The pathological feature and steatosis of the mouse livers were confirmed by H&E staining and Oil red staining, respectively. Furthermore, mRNA expression of the selected LDs localized proteins was examined by the transcriptome.