Cell Engineering for Increasing Production of Recombinant Proteins in Mammalian Cells

Mammalian cell lines are the preferred host cells for the biopharmaceutical industry. Chinese hamster ovary (CHO) and human embryonic kidney 293 (HEK293) cells are frequently utilized in the production of recombinant therapeutic proteins (RTPs) owing to their capacity to facilitate appropriate protein folding and perform accurate post-translational modifications (PTMs). However, there are still some bottlenecks in the biopharmaceutical process using mammalian cells, including lower productivity, higher production cost and increased risk of contamination compared with bacterial or yeast expression systems. In addition to vector, media and bioprocess optimization, advances in host cell engineering including gene overexpression, knockout and knockdown have significantly advanced cell-line development. Besides targeting known genes and pathways, miRNA engineering and omics analysis are also employed to enhance mammalian cell culture performance. Optimization of cell engineering and production processes further drives the development of more efficient mammalian cell expression systems. This review systematically summarizes key achievements in cell engineering and offers insights into potential targets and pathways for improving therapeutic protein production in mammalian cells.