IntelliCyt eBook - October 2017 - 11

Development & Optimization: The Dynamic Duo of Biomanufacturing * Cell-Line Development Poised for Growth

is applied in biomarker research, drug and target
discovery, pathway modeling, mechanism-ofaction studies, and many other areas."

that enables the global investigation of protein
conformational changes in native cell lysates,
with no need to purify the protein of interest.

HRM allows investigation of a cell line's global
expression pattern, and how expression changes
during cell-line development and during the
production of biotherapeutics. Global protein
abundance is an important piece of data.

The Final Word?

"However, one should keep in mind that most
proteins rely on post-translational modifications
(PTMs) like N-glycosylation for their stability and
proper solubility," clarifies Dr. van Sint Fiets. "PTMs
containing peptides can be enriched and quantified on a global scale using HRM-MS."
Protein folding is another quality attribute of
interest. "To investigate folding," says Dr. van Sint
Fiets, "we have recently acquired an exclusive
license that combines HRM-MS with technology

| GENengnews.com

Horizon Discovery's Dr. Freeman notes that in
the 30 years that therapeutic proteins have been
produced in CHO cells, the only significant parental
cell-line improvement with broad commercial
uptake has been the single-gene GS knockout.
Given Horizon Discovery's expertise in this area,
this represents a significant opportunity for further
development of CHO lines through genome engineering, which has not yet been extensively utilized to optimize performance. But not all experts
are sold on the idea that genetic manipulation
can achieve tangible benefits in CHO cells.
Florian Wurm, Ph.D., emeritus professor at the
Swiss Federal Institute of Technology and founder

and CSO of the protein expression services company ExcellGene, has long maintained that improvements in upstream titers have resulted almost
entirely from improved understanding of culture
media and feeds. The problem with the CHO cell,
as a substantial body of research demonstrates, is
its inherent genetic instability and heterogeneity.
All cell lines undergo genetic changes over time
that result in significant phenotypic differences.
The CHO cell, moreover, undergoes more subtle
genomic drifting whose effects may not readily
be anticipated.
"Cell engineering by genomic interaction is a
very tough issue in CHO, a cell host that is
constantly changing," comments Dr. Wurm. "This
is why I am critical of the overstated expectations
from genomic sequencing and its applications.
At ExcellGene, we routinely generate 5-10 g/L
using entirely unmodified CHO cells." n

http://www.GENengnews.com

IntelliCyt eBook - October 2017

Table of Contents for the Digital Edition of IntelliCyt eBook - October 2017