Cell Line-Specific Features of 3D Chromatin Organization in Hepatocellular Carcinoma [Hi-C]
Liver cancer, particularly hepatocellular carcinoma (HCC), poses a significant global threat to human lives. To advance the development of innovative diagnostic and treatment approaches, it is essential to examine the hidden features of HCC, particularly its 3D genome architecture, which is not well understood. In this study, we investigated the 3D genome organization of four HCC cell lines—Hep3B, Huh1, Huh7, and SNU449—using in situ Hi-C and ATAC-seq. Our findings revealed that HCCs had elevated long-range interactions compared to HMECs, both intra- and interchromosomal. Unexpectedly, they displayed cell line-specific compartmental modifications at the Mb scale, which could aid in determining HCC subtypes. At the sub-Mb scale, we observed a decrease in intra-TAD interactions and chromatin loops in HCCs compared to HMECs. Lastly, we discovered a correlation between gene expression and 3D chromatin architecture in SLC8A1, which encodes the sodium-calcium antiporter known to induce apoptosis. Our findings suggest that HCCs have a distinct 3D genome organization that is different from normal and other cancer cells. Overall, we take this as evidence that genome organization plays a crucial role in cancer phenotype determination. Further exploration of epigenetics in HCC will lead us to a better understanding of specific gene regulation mechanisms and uncover novel targets for cancer treatments. Overall design: The 3D chromatin organization of human mammary epithelial cells (HMECs, as a control) and four hepatocellular carcinoma cell lines were analyzed via Hi-C sequencing. Please note that each processed data was generated from two biological replicates.