Using Metabolomics to Identify Cell Line-Independent Indicators of Growth Inhibition for Chinese Hamster Ovary Cell-based Bioprocesses.

Nicholas Alden,Ravali Raju,Alan Gilbert,Kyle Mcelearney,Kyongbum Lee,James Lambropoulos,Rashmi Kshirsagar

doi:10.3390/metabo10050199

Abstract

Chinese hamster ovary (CHO) cells are widely used for the production of biopharmaceuticals. Efforts to improve productivity through medium design and feeding strategy optimization have focused on preventing the depletion of essential nutrients and managing the accumulation of lactate and ammonia. In addition to ammonia and lactate, many other metabolites accumulate in CHO cell cultures, although their effects remain largely unknown. Elucidating these effects has the potential to further improve the productivity of CHO cell-based bioprocesses. This study used untargeted metabolomics to identify metabolites that accumulate in fed-batch cultures of monoclonal antibody (mAb) producing CHO cells. The metabolomics experiments profiled six cell lines that are derived from two different hosts, produce different mAbs, and exhibit different growth profiles. Comparing the cell lines’ metabolite profiles at different growth stages, we found a strong negative correlation between peak viable cell density (VCD) and a tryptophan metabolite, putatively identified as 5-hydroxyindoleacetaldehyde (5-HIAAld). Amino acid supplementation experiments showed strong growth inhibition of all cell lines by excess tryptophan, which correlated with the accumulation of 5-HIAAld in the culture medium. Prospectively, the approach presented in this study could be used to identify cell line- and host-independent metabolite markers for clone selection and bioprocess development.

Highlights

Chinese hamster ovary (CHO) cells are among the most widely used production hosts for biopharmaceuticals, especially monoclonal antibodies, due to their capacity to support proper protein folding and post-translational modifications that are critical for therapeutic efficacy [1].Advances in process control, medium formulation, and host cell engineering have dramatically increased the volumetric productivity of CHO cell lines [2], with titers for some products reaching10 grams per liter or higher [3].Despite progress, limitations remain with respect to productivity
To obtain a global profile of metabolites for each cell line at different growth stages, culture medium samples were collected while the cultures were in exponential growth and when net growth had peaked prior to the cultures entering a period of decline in viable cell density (VCD)
Using untargeted LC–MS experiments, we correlated the growth of monoclonal antibody (mAb)-producing CHO cells experiments, thein growth of mAb-producing cells cultured in fed-batch reactors with metabolites we thatcorrelated accumulated the culture medium

Summary

Introduction

Chinese hamster ovary (CHO) cells are among the most widely used production hosts for biopharmaceuticals, especially monoclonal antibodies (mAbs), due to their capacity to support proper protein folding and post-translational modifications that are critical for therapeutic efficacy [1].Advances in process control, medium formulation, and host cell engineering have dramatically increased the volumetric productivity of CHO cell lines [2], with titers for some products reaching10 grams per liter or higher [3].Despite progress, limitations remain with respect to productivity. Chinese hamster ovary (CHO) cells are among the most widely used production hosts for biopharmaceuticals, especially monoclonal antibodies (mAbs), due to their capacity to support proper protein folding and post-translational modifications that are critical for therapeutic efficacy [1]. Medium formulation, and host cell engineering have dramatically increased the volumetric productivity of CHO cell lines [2], with titers for some products reaching. One major source of productivity limitation in fed-batch bioreactors is the accumulation of metabolic byproducts that reduce cell growth, viability and/or protein production [4]. Controlling these byproducts, notably lactate and ammonia, has in some cases substantially improved the performance of CHO cell-based bioprocesses [5].

Methods

Results

Conclusion