Susan M. Browne

Bio: Susan M. Browne is an academic researcher from University College Dublin. The author has contributed to research in topics: Cell culture & Haematopoiesis. The author has an hindex of 5, co-authored 7 publications receiving 267 citations.

Defining viability in mammalian cell cultures

Abstract: A large number of assays are available to monitor viability in mammalian cell cultures with most defining loss of viability as a loss of plasma membrane integrity, a characteristic of necrotic cell death. However, the majority of cultured cells die by apoptosis and early apoptotic cells, although non-viable, maintain an intact plasma membrane and are thus ignored. Here we measure the viability of cultures of a number of common mammalian cell lines by assays that measure membrane integrity (a measure of necrotic cell death) and assays that measure apoptotic cells, and show that discrepancies in the measurement of culture viability have a significant impact on the calculation of cell culture parameters and lead to skewed experimental data.

Analysis of an artificially selected GS‐NS0 variant with increased resistance to apoptosis

Abstract: Heterogeneity in gene expression and pheno-typic traits is an inherent feature within the ‘‘clonal’’ celllines used for biopharmaceutical production. This featurecan allow the selection of cell lines with improved pheno-types and adaptation to growth under preferential condi-tions to improve productivity or provide a platform to studythe molecular basis of improved characteristics. A repeatedprocess of extended batch culture of a recombinant antibodyproducing GS-NS0 myeloma cell line generated a stablevariant cell line displaying increased resistance to bothenvironmental stresses and chemical apoptosis inducers,and resulted in extended culture viability and increasedantibody production. An interesting feature of the variantcell line was an altered metabolic state with consumption oflactate as the culture progressed. The variant cell line alsoshowed altered expression of proteins associated with autop-hagy suggesting a role for this process in extending cellsurvival in culture. Targeted transcriptomic analysis wascarried out on the parental and variant cell lines using aqRT-PCR array containing a panel of apoptosis-associatedgenes to elucidate both the predominant apoptotic pathwaysin the NS0 cell line with batch culture progression, and thealtered gene expression contributing to increased survival inthe variant line. Results indicated a balance between pro-and anti-apoptotic signaling is triggered with the onset ofcell death in the NS0 cell line. Pro-survival pathways such asNFkB signaling and the unfolded protein response wereimplicated along with death receptor, endoplasmic reticu-lum stress and p53 mediated apoptotic pathways. Theidentification of altered gene expression in the variant cellline also provides several potential targets for cell engineer-ing strategies to create improved cell lines for production.Biotechnol. Bioeng. 2011;108: 880–892. 2010 Wiley Periodicals, Inc.KEYWORDS: apoptosis; artificial selection; NS0; transcrip-tomic; autophagy; cell culture

Biopharmaceutical benchmarks 2010

Abstract: Over the past four years, several new types of experimental biologic treatment have received commercial registration, but the emergence of biosimilars represents the biggest shift in the biologic approval landscape.

Advances in Mammalian Cell Line Development Technologies for Recombinant Protein Production

Abstract: From 2006 to 2011, an average of 15 novel recombinant protein therapeutics have been approved by US Food and Drug Administration (FDA) annually. In addition, the expiration of blockbuster biologics has also spurred the emergence of biosimilars. The increasing numbers of innovator biologic products and biosimilars have thus fuelled the demand of production cell lines with high productivity. Currently, mammalian cell line development technologies used by most biopharmaceutical companies are based on either the methotrexate (MTX) amplification technology or the glutamine synthetase (GS) system. With both systems, the cell clones obtained are highly heterogeneous, as a result of random genome integration by the gene of interest and the gene amplification process. Consequently, large numbers of cell clones have to be screened to identify rare stable high producer cell clones. As such, the cell line development process typically requires 6 to 12 months and is a time, capital and labour intensive process. This article reviews established advances in protein expression and clone screening which are the core technologies in mammalian cell line development. Advancements in these component technologies are vital to improve the speed and efficiency of generating robust and highly productive cell line for large scale production of protein therapeutics.