Building and commercialisation of a new mammalian cell factory platform

Currently industry standard cell factory platforms for manufacture of secreted therapeutic proteins are based around variants of CHO cells, where variants are either natural or engineered auxotroph's for key intermediates in the synthesis of amino acids or nucleotides, essential to support cell growth. Current state-of-the-art recombinant protein production uses genetic vectors which co-express a desired recombinant gene plus a selection marker, using an appropriate CHO cell variant. Only those cells which take up the co-expression vector can be selected on medium that lacks added glutamine (GS) or nucleosides (DHFR). Both systems have the potential for amplification with small molecular weight inhibitors - methionine sulphoxamine (MSX) for GS and methotrexate (MTX) for DHFR. Inclusion of inhibitors in the selection process enables the isolation of cells with higher copies of GS or DHFR which, being genetically linked to the co-expressed recombinant gene, leads to higher expression of the recombinant gene. Consequently, production per cell can be extensively increased and results in productivity suitable for commercial use. Metabolomics studies with CHO cells in the Dickson laboratory have identified a metabolic target that, in a manner analogous to (but distinct from) that of GS, offers a powerful co-expression genetic vector selection system, amenable to knockdown (again analogous to the GS Xceed1 system, developed by Lonza). Several small molecular weight chemicals are potent inhibitors of the metabolic target (analogous to MSX), offering the potential to selection of amplified gene copy. The identified metabolic target is fundamental to cell growth, is in a critical metabolic pathway and, unlike GS, cannot be bypassed by other nutrients such as asparagine. It is also cell-agnostic for potential cell host application. We hypothesise that this platform provides huge potential for synthetic interventions in terms of vector development and host cell line engineering, offering an alternative and improved metabolic selection system to produce therapeutic proteins. This metabolic target and associated gene constitute novel intellectual property. Once exemplified it is intended that the technology would be patented, and that this patent, the materials generated (such as cell lines, vectors and media) would support future commercialisation The PhD student will be responsible for the technical development of the platform, generation of novel cell lines, cell culture medium and other components with design and application of synthetic biology constructs, preparation of knockout cell lines and cell culture components such as medium. Once developed these key components will enable a proof-of-concept evaluation of the platform using a relevant industrial molecule. Production of proteins is of key importance for both therapeutic and nontherapeutic proteins. With global annual sales of therapeutic proteins of >£200Bn, the biomanufacturing sector is an economic leader for the UK. The platform developed in this PhD would be offered as a potential competitor to the technology already reaping commercial dividends for companies such as Lonza, Fuji and Horizon. Currently the lack of freedom to operate and the high cost of entry makes manufacturing expensive and limits the emergence of new companies with innovative products, lacking access to the required technology. A key aim of this project is to develop an innovative, industry-leading, open-source expression platform with significantly flexible license terms, thereby driving significant industry uptake. Revenues would be generated through sales of platform components, technical support and partnerships. The availability of expression platforms un-encumbered by stringent licensing fees would have great attraction to SME's and academic innovators. This expression system has completed an initial proof of concept project undertaken between Pathway Biopharma and an MSc student in the Dickson lab.