TTP Labtech, Phenotypic Screening - 14

PHENOTYPIC SCREENING an e-Book Series Cellular Models for Finer Screening

efficient drug screening.
Cell-mediated contraction of the collagen matrix
is known to be regulated by transforming growth
factor-β (TGF-β), which signals via the Smad pathway
to modulate the expression of downstream effectors
such as connective-tissue growth factor. "We found
that brief bursts of TGF-β in the 3D spheroid assay
prompted contraction of the matrix, a phenomenon
we did not observe in the conventional 2D assay,"
remarked Dr. Takayama. Though such modeling of
cell-mediated contraction, the 3D assay can more
accurately contextualize in vivo biological processes.
Tumor Spheroids
Fredika A. Robertson, Ph.D., executive
director for clinical research services at Virginia
Commonwealth University's Center for Clinical
and Translational Research, described the
development of a tumor spheroid system for
small compound screening. This system was
developed using tumor cells isolated from the
pleural fluid of breast cancer patients.
"These freshly isolated metastatic tumor cells
14 | GENengnews.com

spontaneously form 3D multilayered tumor
spheroids, and have several advantages over 2D
monolayer cultures for screening," Dr. Robertson
pointed out. These advantages include the
enrichment in the 3D spheroids of cancer stem
cells or tumor-initiating cells expressing markers
such as CD44+, ALDH-1+, and CD133, as well
as the recapitulation by the spheroids of the
necrotic center that exists in tumors beyond
1-2 mm in size.
"We found that our 3D tumor spheroid
system mimics activation of multiple cellular signaling
pathways, allowing us to identify the activation of
specific signaling pathways in breast metastasis,"
said Dr. Robertson. With her group, Dr. Robertson
showed that the receptor tyrosine kinase anaplastic
lymphoma kinase (ALK) is activated in preclinical models of inflammatory breast cancer, where it
signals through a variety of downstream pathways,
including JAK1/STAT3, AKT, and mTOR.
"We found that the ALK inhibitor, Crizotinib
[Xalkori®, Pfizer] effectively eradicates the 3D tumor
spheroids from patients with ALK+ tumors,"

Dr. Robertson pointed out. "This is an example of
how the identification of the biological signaling
pathways that are activated in our patient-derived
3D tumor spheroid systems directly led to clinical
trials using this targeted therapeutic."
Tumor spheroids were also the subject of a
presentation by Jason Ekert, Ph.D., senior research
scientist at Janssen Research and Development.
Dr. Ekert described efforts to develop a tumor
model that more faithfully recapitulated the role
of cancer signaling pathways in patient tumors.
Pathways involving the transmembrane receptor
kinases epidermal growth factor receptor (EGFR)
and cMET are involved in the transduction of
growth factor signals to the cell, and are thought
be active in a large number of lung tumors.
"We were interested in better understanding
the differences between 2D monolayer and 3D
spheroid lung tumor cultures in the context of the
EGFR-cMET cancer biology pathway," explained
Dr. Ekert. "Our flow cytometry data told us that
EGFR and cMET expression was reduced in
spheroid cultures compared to monolayer cultures,


http://www.GENengnews.com

TTP Labtech, Phenotypic Screening

Table of Contents for the Digital Edition of TTP Labtech, Phenotypic Screening

Contents
TTP Labtech, Phenotypic Screening - 1
TTP Labtech, Phenotypic Screening - 2
TTP Labtech, Phenotypic Screening - 3
TTP Labtech, Phenotypic Screening - Contents
TTP Labtech, Phenotypic Screening - 5
TTP Labtech, Phenotypic Screening - 6
TTP Labtech, Phenotypic Screening - 7
TTP Labtech, Phenotypic Screening - 8
TTP Labtech, Phenotypic Screening - 9
TTP Labtech, Phenotypic Screening - 10
TTP Labtech, Phenotypic Screening - 11
TTP Labtech, Phenotypic Screening - 12
TTP Labtech, Phenotypic Screening - 13
TTP Labtech, Phenotypic Screening - 14
TTP Labtech, Phenotypic Screening - 15
TTP Labtech, Phenotypic Screening - 16
TTP Labtech, Phenotypic Screening - 17
TTP Labtech, Phenotypic Screening - 18
TTP Labtech, Phenotypic Screening - 19
TTP Labtech, Phenotypic Screening - 20
TTP Labtech, Phenotypic Screening - 21
TTP Labtech, Phenotypic Screening - 22
TTP Labtech, Phenotypic Screening - 23
TTP Labtech, Phenotypic Screening - 24
TTP Labtech, Phenotypic Screening - 25
TTP Labtech, Phenotypic Screening - 26
TTP Labtech, Phenotypic Screening - 27
TTP Labtech, Phenotypic Screening - 28
https://www.nxtbook.com/nxtbooks/gen/ttplabtech_phenotypicscreening
https://www.nxtbookmedia.com