Transcriptional profiling of phenotypically different Epo‐Fc expressing CHO clones by cross‐species microarray analysis

Chinese hamster ovary (CHO) cells exhibit large variabilities regarding growth, recombinant protein production and post-translational processing during cell line development and clone selection. To accelerate the development of stable high quality cell factories, new efficient strategies for cell screening and clone selection are required. In our work, we combined phenotypic characterisation of recombinant CHO clones during early cell line development with transcription profile analysis using cross-species microarrays. The objective was to identify genes or gene patterns that correlate with clone specific alterations in terms of productivity, sialylation capacity and stress resistance. In all high producer clones transcriptional profiling revealed a common enrichment of gene ontology categories related to protein metabolism, transcription, nucleus and nucleolus, whereas no common genes were differentially regulated in clones showing higher sialylation capacities. Furthermore, we identified predictive stress-related marker genes that were up-regulated in one clone without showing the corresponding phenotype at an early stage of development. Thus, we successfully applied gene expression profiling to allocate transcriptomal differences to specific phenotypes that changed during cell line development. These promising results will further increase our efforts to develop CHO specific microarrays that deliver information about the suitability of a clone candidate for industrial production.