Overexpression of biliverdin reductase A leads to ROS-independent sensitization of ovarian adenocarcinoma cells to gemcitabine.

AIMS: Biliverdin reductase A (BLVRA) is a key enzyme in bilirubin metabolism, where it reduces biliverdin to bilirubin. Bilirubin is a potent antioxidant that protects cells from oxidative stress. Therefore, reduced or deregulated BLVRA activity may contribute to increased oxidative DNA damage, which is one of the factors leading to the neoplastic transformation of cells.

METHODS

Human ovarian adenocarcinoma A2780 cells were transfected with a PiggyBac vector to achieve BLVRA overexpression. A2780 clones showing the most significant BLVRA gene overexpression were analyzed by proteomics and flow cytometry to assess rective oxygen species (ROS) production.

RESULTS

Our results indicate that BLVRA overexpression increases the sensitivity of A2780 cells to doxorubicin and gemcitabine, with the most pronounced effect observed in the J clone. In this clone, the highest level of BLVRA overexpression correlated with significant alterations in the p53 signaling pathway. Upregulation of key effectors such as Bax and CDKN2A indicates a potential role for BLVRA in promoting pro-apoptotic responses. Moreover, BLVRA overexpression increased the sensitivity of A2780 cells to gemcitabine independently of ROS.

CONCLUSIONS

This study broadens our understanding of BLVRA in ovarian cancer. In cells with intact p53 signaling, BLVRA overexpression can paradoxically enhance cytotoxic response to certain drugs, particularly gemcitabine.