studies

1164A AASLD ABSTRACTS HEPATOLOGY, October, 2015
This study suggests that TGFβ1 is involved in CCA tumor progression
and may mediate this process through miR-34a downstream
signaling pathways, raising the possibility that TGFβ1
signaling may offer potential therapeutic targets to inhibit CCA
development and growth.
Disclosures:
The following authors have nothing to disclose: Chiung-Kuei Huang, Arihiro
Aihara, Yoshifumi Iwagami, Tunan Yu, Rolf I. Carlson, Hironori Koga, Miran
Kim, Jack R. Wands
1963
Hepatic Ruvbl1 is key regulator of glucose homeostasis
and promotes hepatocellular carcinoma progression in
vivo.
Tommaso Mello 1,2 , Francesca Zanieri 1 , Elisabetta Ceni 1 , Mirko
Tarocchi 1 , Giada Marroncini 1 , Simone Polvani 1 , Sara Tempesti 1 ,
Oxana Bereshchenko 3 , Stefano Milani 1,2 , Andrea Galli 1,2 ; 1 University
of Florence, Florence, Italy; 2 Careggi University Hospital,
Florence, Italy; 3 University of Perugia, Perugia, Italy
The AAA+ ATPase Ruvbl1 is overexpressed in several human
cancers, including hepatocellular carcinoma (HCC), in which
high Ruvbl1 expression correlates with a poor prognosis. A
growing body of data from in vitro models supports the concept
that deregulation of Ruvbl1 expression occurs in cancer to promote
its growth and progression, making this protein an attractive
target for anti-cancer therapies. However, whether Ruvbl1
actively drives HCC onset and progression remains speculative.
To challenge this question we realized an hepatocyte-conditional
Ruvbl1 +/- mouse and evaluated the number and size
of tumor foci induced by DEN. Ruvbl1 +/- mice were obtained
by crossing Ruvbl1-floxed with Albumin-Cre deleter mice. The
male offspring were subjected to a single i.p. injection of DEN
(5mg/kg) to induce liver cancer, and were monitored up to one
year after cancer induction. Contrary to our expectations, we
found that despite an initial delay in the appearance of liver
cancer 6 month after DEN injection, conditional Ruvbl1 +/- mice
eventually developed larger tumors that control floxed mice
9 and 12 months after tumor induction. Ruvbl1 +/- mice (not
DEN-injected) showed impaired basal hepatocyte turnover and
strikingly lower regeneration after 70% hepatectomy, confirming
that Ruvbl1 support cell growth in vivo. We observed that
in the hemizygous mice Ruvbl1 expression was reduced by
50% in normal hepatocytes but not within the tumors, which
indeed overexpressed Ruvbl1 regardless of the mouse genetic
background, suggesting that Ruvbl1 overexpression is a central
event in HCC onset. Hepatic-Ruvbl1 +/- mice developed mild
hyperglycemia, impaired glucose tolerance, insulin resistance,
had reduced liver glycogen content and increased somatic
growth. Moreover, mRNA expression of several mTOR targets
(SREBP-1c, HIF1α, PGC-1α, PPARγ) were reduced in Ruvbl1 +/-
mice. Ruvbl1 silencing in non-transformed hepatocytes (AML-
12) resulted in reduced mTOR expression and impaired
PI3K-Akt-mTOR signaling in response to insulin, as well reduced
cell growth. By 2D-DIGE proteomics we identified key enzymes
of glycolysis as down-regulated proteins in Ruvbl1-silenced
hepatoma cells. Taken together these results highlight a novel
role of Ruvbl1 in the maintenance of hepatic glucose homeostasis
and insulin-sensitivity through the Akt-mTOR pathway, and
strongly suggest that deregulation of this pathway by Ruvbl1
overexpression is a key event driving HCC progression.
Disclosures:
Stefano Milani - Grant/Research Support: Gilead Sciences, Merck Sharp and
Dohme, Abbvie
The following authors have nothing to disclose: Tommaso Mello, Francesca Zanieri,
Elisabetta Ceni, Mirko Tarocchi, Giada Marroncini, Simone Polvani, Sara
Tempesti, Oxana Bereshchenko, Andrea Galli
1964
MicroRNA-207 controls Prp19 expression in hepatocellular
carcinoma
Ji-Min Zhu, Xi-Zhong Shen; Department of Gastroenterology,
Zhongshan Hospital of Fudan University, Shanghai, China
INTRODUCTION: microRNAs (miRNAs) are small non-coding
RNA molecules of 21-24 nt that regulate the expression of
numerous target genes by transcriptional inhibition or translational
repression. Multiple lines of evidence suggest that miR-
NAs play important roles in tumor (such as, hepatocellular
carcinoma (HCC)) development, progression, invasion, metastasis
and prognosis. Our previous unpublished work suggested
that microRNA-207 (miR-207) upregulates in HCC tissues than
in normal liver tissues. Unfortunately, our understanding of the
molecular mechanisms that governs its role in development,
progression, invasion, metastasis and prognosis remains fragmentary.
AIMS & METHODS: In this study, a genome-wide
miRNA microarray was used to identify differentially expressed
miRNAs in HCCs patients. Next, miR-207 expression in normal
liver tissues, HCC tissues and adjacent non-tumor tissues was
validated, and the predictive values of miR-207 for the prognosis
of HCC patients were explored using χ2 test, Student’s
t test, paired t test, and Mann-Whitney test. The biological
roles of miR-207 and its underlying roles in HCC were also
investigated in the Huh7, MHCC-97H, SMMC-7721, L02 and
Hep3B cell lines. RESULTS: Forty-two miRNAs were differentially
expressed in HCCs. Several of these miRNAs were previously
found deregulated in other cancers. Additionally, the
miR-207 was found upregulated in ∼80% of HCCs and in all
HCC-derived cell lines. Overexpressed intratumoral miR-207
was associated with poor survival rate (P < 0.001), and was
an independent prognostic factor for overall survival rate (P <
0.001) in the patients with HCC. Overexpression of miR-207 in
L02 cell line remarkably enhanced cell proliferation, migration,
and invasion; while inhibition of miR-207 in Hep3B cell line
caused the opposite effects. Further study found that miR-207
suppressed the expression of pre-Mrna processing factor 19
(Prp19) by directly binding to its 3’-untranslated region, and
sensitized Hep3B cell to CDDP-induced apoptosis. Moreover,
miR-207 expression levels correlated positively with Prp19 in
human HCC tissues. Western blot showed that overexpression
of miR-207 in L02 cell upregulates the expression of Prp19,
while inhibition of miR-207 in Hep3B cell downregulates the
expression of Prp19, suggesting that Prp19 might play as a
oncogene in HCC. CONCLUSION: Taken together, our findings
suggest that miR-207 could play a role in the development of
HCC, at least in part, by modulating Prp19. These findings
establish a basis toward the development of therapeutic strategies
aimed at blocking miR-207 in HCC.
Disclosures:
The following authors have nothing to disclose: Ji-Min Zhu, Xi-Zhong Shen