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BLOG biotech : Jun 28, 2012

Working Toward Better, Cheaper Drug Discovery

  • Sue Pearson, Ph.D.
Many of the technologies exhibited at this years’ European Lab Automation
(ELA) in Hamburg are geared toward cutting assay costs, improving cell
and tissue preparation, or speeding up cell analysis workflow. The mood at the
conference was downbeat with few new product launches. Is this a reflection of
the financially trying times in Europe at the moment or just the fact that all
the instrument manufacturers had already had their product launches at
Analytica, or were keeping their powder dry for ACHEMA?

Big Is Not Always Best
Sample preparation was one hot topic at ELA, with many companies now
convinced that just having vast numbers of tissues or compounds is not enough
for cost-effective and successful preclinical drug screening outcomes.
“Having the biggest compound collection in the big pharma world has lots of
pitfalls as well as advantages,” said Rose Gonzales, Ph.D., director of compound
management and distribution at Pfizer. “We realized in 2009 that we had too many
compounds that looked the same, and also many that we call uglies, which are
reactive or unusable compounds. We set about better characterizing our
collection, and by doing this have reduced our library by almost one million
compounds.”

Mark Wigglesworth, Ph.D., manager of lead optimization sample management
technologies at GlaxoSmithKline, added: “We also concluded in 2009 that our
compound collection contained too many compounds with high lipophilicity, and we
were running too many screens with undesirable compounds. This was a major task,
but we have significantly enhanced our compound collection and used new software
to help us cherry pick the right compounds from our libraries. By cherry picking
many compounds, we’re now able to perform screens more efficiently instead of
screening undesirable compounds, which when you’re screening hundreds of
thousands of compounds becomes a substantial cost savings.”

Fail to Prepare, Prepare to Fail
“The number one roadblock to successfully screening tissues is the
availability of high-quality samples, which haven’t experienced degradation or
changes to the RNA and protein expression. While degradation is an issue, the
main problem is an active change of RNA and protein profiles of cells caused by
the surgical techniques used to remove the tissue, the drugs the patient is on,
and most importantly how the tissue is prepared post-surgery,” stated Professor
Hartmut Juhl, founder and CEO of Indivumed, a German firm that specializes in
isolating and banking biological samples from patients suffering from bowel,
lung, breast, and colorectal cancers.

Professor Juhl presented evidence to substantiate this claim, by showing how
significantly the protein profiles of two different proteins isolated from 40
different cancer samples changed pre- and post-surgery.
To overcome this problem, Professor Juhl explained that his company has
designated nurses on surgical teams in eight cancer centers in Germany. These
nurses prepare for surgery along with the surgical team, receiving information
about a patient’s treatment and condition. When the tissue is removed, it is
taken into a room next to the surgical suite, where it is sectioned into pieces
that are then fixed and frozen within 5–10 minutes of being removed. Professor
Juhl concluded: “We have 300 clinical data points on each tissue we collect and
we now have over 15,000 patient samples. This is expensive and time consuming to
do but we believe our process does provide tissues that are of high value in
preclinical screening.”

Another new product featured at ELA was Cellectricon’s Cellaxess® Elektra
Discovery Platform, for automated cellular electric field manipulation. Johan
Pihl, Ph.D., product manager at Cellectricon, said, “The platform is highly
versatile and can be used to transfect siRNA and cDNA into primary cell cultures
in genomic screening applications. The system can also deliver small molecules
and antibodies, and we believe it will enable scientists working with primary
adherent cell types such as diffentiated neurons and cardiomyocytes in lead
identification and target validation. The platform lets users perform in situ
manipulation and monitoring of cell cultures directly in 96- and 384-well HCS
compatible microplates without affecting viability and cellular morphology,
enabling the manipulation and study of more biologically relevant cell systems
such as primary and stem-cell derived cultures.

According to Dr. Pihl, Cellectricon is also offering access to the platform
through its discovery assay development and discovery screening services. “The
hybrid business model allows researchers in pharma/biotech and academia to
acquire the Cellaxess Elektra platform for certain applications or to outsource
to us for discovery screening services employing electric field manipulation of
cells in CNS and cardiovascular applications,” he explained.

Cellaxess Elektra can also be configured with an integrated imaging-based
microplate reader for recording of transient fluorescence and luminescence
signals from living cells in real-time to provide data in CNS/pain and
cardiovascular research applications.
Cellectricon supplies a plate reader, but readers from other manufacturers
could be integrated, and there were several available at ELA. One example was
the HTS multi-mode microplate PHERAstar FS, which was exhibited by BMG LABTECH.

“Using the PHERAstar FS, cell-based microplate assays are now possible that were
not possible before,” said Silke Angersbach, Ph.D., the firm’s regional manager.
“When measuring cell-based assays on a microplate reader, it is necessary to
measure from the plate bottom. Most instruments use flexible, inefficient fiber
optics to measure from the microplate bottom. The PHERAstar FS, however, uses a
Direct Optic Bottom Reading approach analogous to a microscope. Since fiber
optics are not used, the overall signal is significantly higher (up to 10-fold)
compared to instruments that use fiber optics.”

3-D and Primary Cell Analysis—The Future?
With an estimated 30% of scientists looking at switching to using 3-D and
primary cell culture for screening by 2015, the number of technologies geared
around analyzing whole cells was evident at ELA. The ImageXpress® Micro XL
Widefield HCS System from Molecular Devices is an interesting new product for
this. The company claims that the ImageXpress Micro XL microscope lets
researchers image three times the area of its predecessors.

“We have built this ImageXpress system for digital, fully automated confocal
microscopy,” noted Christian Holz, European application specialist, imaging. “It
uses solid-state lighting and a very high-resolution, 16 bit SCMOS camera to
enable the researcher to capture a field of view three times larger than
previous generation instruments. This will be useful for applications such as
imaging neural networks. The software has been upgraded to allow users to take
ZED stacks and have more accurate information about 3-D cells in the stacks, as
this is very much what scientists now need with their research.”

There is also a large database for image storage, Holz explained.  
“The images of 3-D cells often require considerable storage space, so we have built a
database that holds terabytes of information securely.”

High-content analysis of 3-D cells was also discussed at ELA. “There’s lots
of buzz around phenotypic screening, as over 60 percent of new first in class
drugs that have emerged in recent years are from phenotypic screening using
cell-based assays. So it makes sense to try and increase the throughput in
sensitive techniques like flow cytometry,” explained Yen Kim Luu, Ph.D, manager,
assay development at IntelliCyt, a U.S.-based manufacturer of screening
solutions. “This is what we’re doing with our HyperCyt® high-content flow
cytometry screening system.”

Dr. Luu described the levels of throughput that can now be achieved, stating
that Pfizer has used a 384-well plate-based HyperCyt system in a toxicity screen
to generate 50,000 data points over five days. The group screened 231 compounds
for cardiac or hepatoxic effects and identified 21 different toxicity
profiles.

“Using the HyperCyt technology does take scientists into real-world screening
throughput because read times are only 3 minutes for 96-well plates or 12
minutes for 384-well plates,” Dr. Luu concluded. “This provides fast population
phenotyping and the potential to more accurately screen thousands of compounds
in disease-relevant assays. I believe we’re going to see an increasing number of
high-throughput technologies for 3-D cell analysis being developed and used more
extensively in drug screening in the next decade.”

--
Sue Pearson, Ph.D., is a GEN European writer.