Page 78 - ebook HCC

76 PROGRAMME AND ABSTRACTS GENEVA, SWITZERLAND EASL HCC SUMMIT 77
FEBRUARY 13 - 16, 2014

A PROOF OF CONCEPT STUDY FOR THE Our second approach consists to isolate bipotent mouse embryonic liver cells from E14.5
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TUMOUR SUPPRESSOR EFFECT OF A Apc embryos and treat them with LNA-34a before injection in the liver of control mice.
The tumour development will be followed as previously.
THERAPEUTIC STRATEGY AGAINST MIR-34A
IN MOUSE TUMOURS MUTATED FOR Conclusions: Our work highlights the crucial oncogenic role of miR-34a in tumours
mutated for β-cat. By a LNA strategy, we expect to highlight miR-34a as the first oncogenic
BETA-CATENIN actor in β-cat-mutated HCC, which could be easily targeted. The great potential of this
strategy lies on the modulation of HNF-4α activity, which results in the restoration of the
metabolic program and the control of cell cycle through cyclin D1 targeting.
Angelique Gougelet , Laura Bachelot , Cecile Godard ,
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Chiara Sartor , Benoit Terris , Christine Perret , Sabine Colnot 1
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1 U1016, INSERM, Paris, France
Corresponding author’s e-mail: angelique.gougelet@inserm.fr
BASIC SPEAKERS ABSTRACTS Introduction: microRNAs (miRNAs) are small non-coding RNAs involved in the BASIC SPEAKERS ABSTRACTS
development and the progression of a great variety of tumours, in particular of
hepatocellular carcinoma (HCC). Our team focuses in particular on the role of β-catenin
(β-cat) in liver tumour development. By ChIPseq and RNAseq experiments, we recently
showed a functional antagonism between β-cat and HNF-4α, which is described as a
tumour suppressor in HCC.

Aims: Our objective is to identify candidate miRNAs by miRNAseq, which could be
regulated by β-cat and involved in liver tumourigenesis.

Methodology: This project is realized on transgenic mice exhibiting an overactivation
of β-cat following the deletion of its inhibitor Apc (Apc ). This model is liver-specific and
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inducible by tamoxifen injection. It is a pretumoural model since lower dose of tamoxifen
results in the apparition of tumours mutated for β-cat, which mimic human HCC.

Results: miR-34a is significantly induced following β-cat activation in correlation with a Figure 1 : miR-34a oncogenic role in liver
loss of its target HNF-4α. miR-34a is also significantly increased in the mouse tumours miR-34a is upregulated in tumors from Apc null mice (A) and human β-catenin mutated
obtained following Apc depletion and in HCC patients mutated for β-cat, as compared to HCC (B). miR-34a level was measured by qPCR with a taqman miRNA assay (Applied
normal liver. We thus decided to test the effect of a locked nucleic acid approach against biosystems). C : a locked nucleic acid (LNA) against miR-34a efficiently restores HNF-
miR-34a (LNA-34a) in the progression of tumours mutated for β-cat. The LNA-34a exerts 4α and cyclin D1 level in western-blot. 100nM LNA was transfected for 48h in primary
an anti-proliferative activity on primary hepatocytes isolated from Apc model, while it hepatocytes isolated from Apc KO mice by lipofectamine. D : the LNA against miR-34a
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has no effect on wild-type hepatocytes. This inhibition of proliferation is associated to a inhibits hepatocyte proliferation. 100nM LNA was transfected into primary hepatocytes
decrease of cyclin D1 protein level, a negative target of HNF-4α. We currently initiate the isolated from Apc and control (Ctrl) mice by lipofectamine. E : hypothetized model for
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in vivo study with LNA-34a injection in tumoural Apc mice. As soon as liver tumours miR-34a action.
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are detectable by echography, we intraperitoneally inject the LNA-34a (10mg/kg, once a
week). Tumour development is bimonthly followed by 3D-echography.