A rational approach for bio-production of recombinant proteins in mammalian cell systems

Recombinant protein production technologies lie at the heart of today’s biopharmaceutical industry. Over the years, there has been a steady increase in the use of mammalian cell-based systems, in particular Chinese Hamster Ovary (CHO) cells, for recombinant protein production. This trend can be explained by the capacity of CHO cells for correct post-translational modifications, proper folding of complex proteins, growth at high density in suspension culture and resistance to viral infections. Here, we present a novel workflow and preliminary data focused on tackling fundamental problems related to the current technology used to engineer cell lines, namely clonal heterogeneity, clonal instability, and transgene silencing. Central to our approach is the design and rapid assembly of multi-copy constructs and their targeted integration into optimal loci for protein expression, circumventing the need for random transgene integration and drug-based gene amplification, factors thought to be implicated in clonal instability and clonal heterogeneity. Our approach includes a CHO genome screen using lentivirus followed by high throughput sequencing in order to find stable and high expressing integration loci. Targeted delivery of multi-copy, bio-production modules into newly discovered expression loci can then be achieved using one of several genome-editing techniques.

With this rational approach, we expect to reduce time and labor required to engineer cell lines, ultimately making the recombinant protein production value chain more cost effective.