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CANCER STEM CELLS AND
ONCOLOGY RESEARCH
11th International Conference on
Journal of Medical Oncology and Therapeutics | Volume 3
Mehreen Ahmed et al., J Med Oncl Ther 2018, Volume 3
TARGETING CRC-SC FOR
DIFFERENTIATION – A 3D SCREENING
SYSTEM FOR DIFFERENTIATION
THERAPIES
Mehreen Ahmed, Roya Babaei-Jadidi and Abdolrahman S
Nateri
University of Nottingham, UK
Cancer stem-like cells (CSC) are a subpopulation of tumour cells with
the extraordinary characteristic of self-renewal and also can replenish
themselves. The emerging concept of differentiation therapy advocates
that the efficacy of conventional anticancer treatment will increase upon
forceddifferentiationofCSCs.Therefore, follow-updiscoveryof newdrugs
will involve selective CSC targeting and allowing them to descend to bulk
cancer cells will make them easily targeted by conventional treatment.
Currently, there is no known compound(s) that drive colorectal cancer
(CRC)-SC differentiation. Moreover, current in vitro models fail to comprise
tumour heterogeneity andpredictivepatient outcome inpreclinical setting.
We attempt to harness a patient relevant in vitro screening system to
identify small molecule(s) and to cross-examine CRC-SC differentiation.
At present, we have identified 4 candidate drugs that have been screened
from a library of small molecules consisting of 707 compounds for their
differentiation induction potential. For this, we have established a novel
methodology to screen small molecule-based drugs targeting ‘stemness’
properties on live 3D colonospheres derived from CRC cell lines. We have
optimized our pilot screening with a clinically relevant HDAC inhibitor
and a fluorescent rosamine dye CDy1 in a high throughput plate reader
screening (PRS) manner to detect reductions in fluorescence staining
on live 3D colonosphere. Our results suggest that compounds that
induce differentiation can be identified based on the reduction of CDy1
intensity in 3D colonospheres, backed by immunostaining of stemness
and differentiation markers.Our initial screening suggest that 6% of the
total compounds might be involved in inducing differentiation in CRC-SC
obtained from three CRC cell lines. These compounds were identified
based on distinct morphology changes, colonosphere sizes and intensity
of CDy1. Further follow up data suggest that three of these compounds
antagonize nuclear β-catenin, known to regulate self-renewal at adenoma
and carcinoma stages. We have selected 4 compounds based on their
ability to suppress colony formation, cell growth, and preliminary effects
shown for beta catenin expression. Upon finishing this screening on 3D
colonosphere representingCSCs, wehavebeen focusingon identifying the
mechanisms of our candidate drugs and how they regulate differentiation
on CRC-SC. Using proteomic approach and biochemical analysis, we’re
Mehreen Ahmed is currently persuing her re-
search at the Division of Cancer & Stem Cells,
Cancer Biology Unit, Cancer Genetics & Stem
Cell Group, School of Medicine, University of
Nottingham, UK.
BIOGRAPHY
currently looking at specific targets for these
drugs and to elucidate their mechanisms.
Simultaneously, we are also evaluating these
drugs on patient derived organoids and
tissue explants obtained from both tumour
and normal adjacent tissue to investigate
drug specificity on CSC vs NSC. The lack
of relevant models and suitable screening
methodology are two major impediments in
CRC drug discovery. This study demonstrates
the application of colonospheres in drug
screening and could potently characterise
the mechanisms involved with defined
compounds in CSCs eradication, a major
aspect behind cancer recurrence, resistance
and mortality. Our studies are underway
to identify the targets of candidate drugs
and exploring their mechanism on CRC-SC
specificity. This would be relevant to decipher
the differentiation induction pathways in CRC-
SC.