Expression of DNAJB1-PRKACA oncogene suppresses the differentiation potential of liver progenitor organoids towards a hepatocyte lineage.

Fibrolamellar carcinoma (FLC) is a type of primary liver cancer that predominantly affects healthy adolescents and young adults in a background of normal liver. The DNAJB1-PRKACA fusion gene is an oncogenic driver in FLC tumors. To investigate the oncogenic mechanisms of this fusion gene, we developed a model using human liver progenitor organoids engineered to express DNAJB1-PRKACA. Single-nucleus RNA sequencing of these organoids revealed an upregulation of genes that significantly overlap with those expressed in FLC epithelial cells. Additionally, the expression of DNAJB1-PRKACA led to the downregulation of genes coding for markers of mature epithelial cells, indicating a shift toward a less differentiated state. When compared to wild-type liver progenitor organoids, which exhibit a strong ability to differentiate into hepatocytes, the DNAJB1-PRKACA-expressing liver progenitor organoids displayed a markedly reduced capacity for hepatocyte differentiation. These findings suggest that the DNAJB1-PRKACA fusion gene disrupts the normal differentiation process of liver progenitor cells.