Optimizing Recombinant Protein Production in CHO Cells by Silencing the Caspase 8 Associated Protein 2 Gene via the...

Chinese hamster ovary (CHO) cells play a crucial role in biopharmaceutical production due to their ability to produce complex proteins. Enhancing the productivity of CHO cells is essential for meeting the growing demand for biologics. Caspase 8-Associated Protein 2 (CASP8AP2), a key regulator of apoptosis and cell survival, has been identified as a potential target to increase CHO cell productivity. To this end, CRISPR-mediated homology-independent targeted integration (HITI) was used to silence CASP8AP2. Results of the cell viability assay revealed that CASP8AP2-deficient clones (C2, C3, and C4) were more resistant to sodium butyrate (NaBu) compared to native cells, with IC50 values of 11.83, 12.77, 10.25, and 8.55 mM, respectively. Protein production assays showed a significant increase in JRed and luciferase expression in silenced clones (C2 and C4) compared to wild-type cells, with up to 1.2- and 1.9-fold increases for JRed, and 1.4- and 1.7-fold increases for luciferase, respectively. These findings could be attributed to the clones experiencing cell cycle arrest specifically during the S phase. While these results demonstrate proof-of-principle using reporter proteins, future validation with therapeutic biologics such as implementing monoclonal antibodies in bioreactor settings could confirm scalability for industrial bioprocessing. Transcriptomic analyses would further elucidate downstream effects on apoptosis and metabolism pathways. The results suggest that targeting CASP8AP2 could be a promising strategy for improving bioprocess efficiency and yield in CHO cell-based production systems.