Isolation and Characterization of Cancer Stem Cells Using iFP Technique
There has been a growing interest in recent years on cancer stem cells (CSC) and their
implication in cancer biology and therapy.
CSCs refer to a subset of tumor cells that has the ability to self-renew and generate the
diverse cells that comprise the tumor.
These cells have been termed cancer Stem cells to reflect their 'stem-like' properties and
ability to continually initiate and sustain tumorigenesis.
CSCs share important properties with normal tissue stem cells, including self-renewal (by
symmetric and asymmetric division) and differentiation capacity, albeit aberrant.
Multilineage differentiation, however, is not a mandatory feature of a CSC. Furthermore,
these cells are thought to be resistant to conventional cancer therapy including
chemotherapy and radiotherapy which may explain rapid tumor cell repopulation following
treatment mainly by this subtype of cells, therefore new therapeutic method to target CSCs
are now under thorough investigation.
One of the major difficulties in finding and identifying CSC is that they are hard to
isolate, grow, and enrich.
Several in vitro assays have been used to identify stem cells, including sphere assays,
serial colony-forming unit (CFU) assays (replating assays), and label-retention assays.
Studies have also been performed with the goal of determining genetic signatures that define
CSCs. However, each of these methods has potential pitfalls that complicate interpretation
of the results.
Therefore additional method to easily harvest and enrich the CSCs is required. Currently,
the vast majority of cells are cultivated in 2-D flat hard plastic plates and flasks that
are inert to the cells. However CSCs are grown in a 3-D serum free conditions which make
their growth slow and complicated.
Often proteins, such as fibronectin or collagen, have been employed as coatings to render
the plastic more "cell friendly". However yields are still low; costs are high, and require
much floor space (large footprint). Moreover, the cells attached to the plastic must be
trypsinized in order to transfer or to implant affecting the survival of cells exposed to
Fibrinogen is an acute phase protein , occurring at 2-4g/l in human blood, upon treatment
with glucocorticoid, inflammation or trauma, the concentration of fibrinogen increase
Fibrinogen exerts adhesive effect on cultured fibroblast and other cells. Specifically
fibrinogen and its various lytic fragments (D.E ,FPA )were shown to be chemotactic to
macrophage , human fibroblast and endothelial cells.
Fibrin matrix is commonly used surgical hemostasis and tissue sealing Fibrin(ogen) - a
possible candidate from which a 3-D matrix for cell culturing could be fabricated, is the
major component of the blood coagulation system. Native fibrinogen is soluble in aqueous
buffer and cannot usually be employed for cell culture applications, except as a coating for
plastics. However, when mixed with a trace of thrombin, it becomes transformed into an
insoluble fibrin clot that attracts cells and provides a provisional matrix for tissue
1. Generating and enriching CSC (in vitro) from established cell lines of human cancer We
will isolate, purify, and characterize CSC from a series of established cell line
including , U87-MG human glioma, MCF7 breast carcinoma and PANC-1 human pancreatic
adenocarcinoma, using standard techniques as described in Methods . These cells will be
cultured and grown as monolayer's in serum containing medium or as spheres in serum
free medium supplemented by growth factors .(18-7-19) We will evaluate the ability of
the cells to form spheres and characterize their stem cell properties using surface
markers detection and measuring ALDH activity.
2. Growing CSCs on iFP substance:
iFP may exhibit high attachment response for cancer cells, conserve cell surface
marker, and yield optimal growth rate. In addition, the cells on IFP could be
transferred without trypsinization which can diminish cell damage during harvesting
from plastic plate resulting in higher survival.
Cells will be cultured in dishes coated iFP substance as described in the Methods.
After 2 weeks in culture, cells will be harvested identified for CSCs for cancer stem
cell proprieties using the same methods we described above (e.g surface markers and
ALDH activity) .
3. To isolate and enrich CSCs from fresh tumor specimens This aim designed to promote the
implication of iFP in cancer research by studying, harvesting, and growing CSCs
obtained from fresh tumors and subsequently using them for in vitro therapeutic
testing. Such an approach can optimize the therapy which may target this type of cell.
Tumor specimens will be obtained from consenting patients according to the Internal Review
and The Ethics Board.
Tumor samples will be collected from the pathology department from the histological
diagnostic assessment during tumor resection (when the samples are still fresh). Thus
samples will be received in the Laboratory within 30 minutes of surgery.
Tumors will be prepared as single cell suspensions and then will be grown using either
conventional standard method or iFP. Subsequently, cells will be harvested and evaluated for
CSC characteristics using the same method we used for cell lines. A comparison of the yield
of CSC percentage will be performed between iFP and the conventional methodology.
Time Perspective: Prospective
Cancer stem cells percentage
Evaluation of CSCs and non-CSCs population by using several surface markers. For glioma and pancreas, CSC are defined as CD133 positive. For breast carcinoma CSCs are identified as CD44+/CD24-/Low. Percentage of CSCs will be measured for comparing the yield of the methods using iFP and the standard method.
FADI - MIZYED, Dr.
Rambam Health Care Campus
Israel: Ethics Commission
cancer stem cells.ctil