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CANCER STEM CELLS AND
ONCOLOGY RESEARCH
11th International Conference on
Journal of Medical Oncology and Therapeutics | Volume 3
Bidan Nadege, J Med Oncl Ther 2018, Volume 3
STUDY OF CELL REPROGRAMMING
IN A MURINE MODEL: FOLLOW-UP OF
RADIO-INDUCED CANCEROUS STEM
CELLS AND VALIDATION OF THE
CYTOKINES INVOLVED
Bidan Nadege
Inserm, France
Many solid cancers are thought to be organized hierarchically with a
small number of cancer stem cells (CSCs) able to re-grow a tumor
while their progeny lacks this feature. This CSCs are associated with
radioresistance. Recent studies have revealed that noncancer stem cells
may undergo dedifferentiation subsequently obtaining the phenotype
and functions of CSCs. Indeed, ionizing radiation reprogrammed
differentiated breast cancer cells into induced cancer stem cells (iCSCs).
This mechanism of reprogramming can contribute to relapse. CSCs
and iCSCs cannot be distinguished, because they share the same stem
cell-like properties. Breast CSCs can be isolated based on their high
ALDH1 activity, and iCSC studies require sorting of ALDH1-negative
cells. These studies are therefore limited to in vitro experiments. In vivo
reprogramming studies require to design a CSC and iCSC identification
system. We compared different promoters for the use of CSC reporters.
To do so, we built expression vectors with mNeptune fluorophore
expression controlled by different sizes ALDH1A1 and NANOG promoters.
We validated the CSC reporter capability using RTPCR expression, flow
cytometry and functional assay analyses. Indeed, mNeptunepos cells
have an overexpression of stemness-related genes (Oct3/4, Sox2 and
Nanog), as well as an increase of mammosphere forming capacity and
tumorigenicity, compared to mNeptuneneg cells. We also observed an
enrichment for mNeptunepos cells after ionizing radiation and a radiation-
induced reprogramming of mNeptuneneg cells into mNeptunepos cells.
Our observations on CSC reporters showed that the 900 pb sequence of
ALDH1A1 promoter seems to be the best choise for a CSC reporter. Based
of this first study, we selected this promotor andgenerated a multigene
tracing expression vector to distinguish CSC from iCSC at given time
points. This vector contains sequence of CSC reporter, TetON system
for inducible CRE expression, CRE recombinase/loxP sites system and
mNeptune fluorophore. We are currently validating this vector for it use
in vitro before to generate transgenic mice model for CSC and iCSC
reporter. This vector will be a tool for future studies investigating in vivo
reprogramming mechanism.
Bidan Nadege is currently persuing her research
at Inserm, France.
BIOGRAPHY