Context-Dependent Roles of Hes1 in the Adult Pancreas and Pancreatic Tumor Formation

概要

Gastroenterology 2022;163:1613–1629

Context-Dependent Roles of Hes1 in the Adult Pancreas and
Pancreatic Tumor Formation
Saiko Marui,1 Yoshihiro Nishikawa,1,2,3 Masahiro Shiokawa,1 Masataka Yokode,1
Shimpei Matsumoto,1 Yuya Muramoto,1 Sakiko Ota,1 Takeharu Nakamura,1 Hiroyuki Yoshida,1
Hirokazu Okada,1 Takeshi Kuwada,1 Tomoaki Matsumori,1 Katsutoshi Kuriyama,1
Akihisa Fukuda,1 Dieter Saur,4,5 Takashi Aoi,2 Norimitsu Uza,1 Yuzo Kodama,3
Tsutomu Chiba,6 and Hiroshi Seno1

BACKGROUND & AIMS: The Notch signaling pathway is an
important pathway in the adult pancreas and in pancreatic
ductal adenocarcinoma (PDAC), with hairy and enhancer of
split-1 (HES1) as the core molecule in this pathway. However,
the roles of HES1 in the adult pancreas and PDAC formation
remain controversial. METHODS: We used genetically engineered dual-recombinase mouse models for inducing Hes1
deletion under various conditions. RESULTS: The loss of Hes1
expression in the adult pancreas did not induce phenotypic alterations. However, regeneration was impaired after caeruleininduced acute pancreatitis. In a pancreatic intraepithelial
neoplasia (PanIN) mouse model, PanINs rarely formed when
Hes1 deletion preceded PanIN formation, whereas more PanINs
were formed when Hes1 deletion succeeded PanIN formation. In
a PDAC mouse model, PDAC formation was also enhanced by
Hes1 deletion after PanIN/PDAC development; therefore, Hes1
promotes PanIN initiation but inhibits PanIN/PDAC progression.
RNA sequencing and chromatin immunoprecipitationquantitative polymerase chain reaction revealed that Hes1
deletion enhanced epithelial-to-mesenchymal transition via
Muc5ac up-regulation in PDAC progression. The results indicated that HES1 is not required for maintaining the adult
pancreas under normal conditions, but is important for regeneration during recovery from pancreatitis; moreover, Hes1 plays
different roles, depending on the tumor condition.
CONCLUSIONS: Our findings highlight the context-dependent
roles of HES1 in the adult pancreas and pancreatic cancer.

Keywords: Pancreatic Ductal Adenocarcinoma; PanIN; Muc5ac;
Notch.

P

ancreatic ductal adenocarcinoma (PDAC) is a lethal
malignancy with a high mortality rate. PDAC is the
third-/fourth-leading cause of cancer-related deaths in the
United States, Europe, and Japan.1–3 Although several efforts
have been made to establish effective therapies for PDAC,
the 5-year survival rate in PDAC is w5% to 10%.2,4,5 To
overcome the limitations in PDAC treatment, it is important
to understand the molecular mechanism underlying PDAC

formation and identify suitable therapeutic targets.
Reportedly, human PDAC involves gene mutations in 10
core signaling pathways, with the Notch signaling pathway
considered as one of the main pathways.6 Hairy and
enhancer of split-1 (HES1) is the primary downstream
target of the Notch signaling pathway and is known to play
important roles in cell and tissue development.7 However,
the role of HES1 in PDAC remains controversial.
In the development of the pancreas, HES1 is expressed
in stem/progenitor cells at the embryonic stage and is
considered to be important in the maintenance of these cells
as well as in deciding their fate.8,9 Indeed, global Hes1
knockout (KO) mice show pancreatic hypoplasia, which indicates the essential role of Hes1 in pancreas development.9
Although HES1 expression is limited to duct/centroacinar
cells in the adult pancreas under normal conditions, it is
also observed in acinar-to-ductal metaplasia (ADM),10,11
which represents a state of temporal dedifferentiation of
acinar cells under inflammatory conditions. We previously

Abbreviations used in this paper: Ad-Cre-GFP, Cre recombinase and
green fluorescent protein-expressing adenovirus; Ad-GFP, green fluorescent protein-expressing adenovirus; ADM, acinar-to-ductal metaplasia; Aldh, aldehyde dehydrogenase; ChIP-qPCR, chromatin
immunoprecipitation-quantitative polymerase chain reaction; CK, cytokeratin; DMEM, Dulbecco’s modified Eagle medium; ERT2, mutated estrogen receptor; FACS, fluorescence-activated cell sorting; FBS, fetal
bovine serum; GFP, green fluorescent protein; HES1, hairy and enhancer
of split-1; Hes1KO, Hes1-negative cells; Hnf1b;Hes1KO, Hnf1b-CreERT2;Hes1flox/flox; IHC, immunohistochemistry; KO, knockout; mRNA,
messenger RNA; MUC5AC, mucin 5, subtype AC; PanIN, pancreatic
intraepithelial neoplasia; PDAC, pancreatic ductal adenocarcinoma;
Pdx1;Hes1KO, Pdx1-Flp;FSF-R26CAG-CreERT2;Hes1flox/flox; Pdx1;Hes1WT,
Pdx1-Flp;Hes1flox/flox; Pdx1K;Hes1KO, Pdx1-Flp;FSF-R26CAG-CreERT2;FSFKrasG12D;Hes1flox/flox; Pdx1K;Hes1WT, Pdx1-Flp;FSF-KrasG12D;Hes1flox/flox;
Pdx1KP;Hes1KO, Pdx1-Flp;FSF-R26CAG-CreERT2;FSF-KrasG12D;Trp53frt/D;
Hes1flox/flox; Pdx1KP;Hes1WT, Pdx1-Flp;FSF-KrasG12D;Trp53frt/D;Hes1flox/flox;
qRT-PCR, quantitative reverse-transcription polymerase chain reaction;
RNA-seq, RNA sequencing; WT, wild-type.
Most current article
© 2022 The Author(s). Published by Elsevier Inc. on behalf of the AGA
Institute. This is an open access article under the CC BY license (http://
creativecommons.org/licenses/by/4.0/).
0016-5085
https://doi.org/10.1053/j.gastro.2022.08.048

PANCREAS

1
Department of Gastroenterology and Hepatology, Kyoto University Graduate School of Medicine, Kyoto, Japan; 2Division of
Advanced Medical Science, Graduate School of Science, Technology and Innovation, Kobe University, Kobe, Hyogo, Japan;
3
Department of Gastroenterology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan; 4Department of Internal
Medicine II, Klinikum rechts der Isar Technische Universität München, München, Bayern, Germany; 5Division of Translational
Cancer Research, German Cancer Research Center (DKFZ) and German Cancer Consortium (DKTK), Heidelberg, BadenWürttemberg, Germany; and 6Department of Gastroenterology and Hepatology, Kansai Electric Power Hospital, Osaka, Japan

1614 Marui et al

WHAT YOU NEED TO KNOW
BACKGROUND AND CONTEXT
The roles of Hes1 in adult pancreas and pancreatic ductal
adenocarcinoma remain controversial.
NEW FINDINGS
Under inflammatory condition, loss of Hes1 in
centroacinar/terminal duct resulted in pancreatic
atrophy. Hes1 deletion inhibited pancreatic intraepithelial
neoplasia/pancreatic ductal adenocarcinoma initiation,
while it could promote pancreatic intraepithelial
neoplasia/pancreatic
ductal
adenocarcinoma
progression.
LIMITATIONS
This study was performed using mice, murine cells, and
human RNA sequencing data, hence further studies are
warranted in humans.
IMPACT
PANCREAS

Hes1 plays distinct roles in pancreas based on the cellular
context and tumor phase. Hes1 plays an important role in
pancreatic regeneration after inflammation, whereas Hes1
has a suppressive role in pancreatic ductal
adenocarcinoma progression.

reported that HES1 is nonessential for the maintenance of
adult acinar cells under normal and inflammatory conditions.11 In contrast, another study showed that Hes1 deletion in the adult duct cells of Sox9-IRES-CreERT2 knock-in
mice promoted transdifferentiation from duct to acinar cells
with Sox9 suppression.12 Therefore, the precise roles of
HES1 in the adult pancreas are yet to be determined.
PDAC is believed to primarily form from acinar cells
bearing mutant Kras that transform into pancreatic intraepithelial neoplasia (PanIN) through ADM.13 In pancreatic
tumor development, HES1 expression commences at the
ADM stage and continues during PanIN and PDAC formation,10,14 suggesting the involvement of Hes1 in both PDAC
initiation and progression. However, 2 conflicting reports
have been published on the role of HES1 in pancreatic
tumorigenesis.11,15 One report showed that simultaneous
Hes1 deletion and KrasG12D induction in the whole embryonal pancreas accelerated KrasG12D-induced PDAC formation.15 In contrast, simultaneous Hes1 ablation with KrasG12D
induction in adult acinar cells was shown to induce tumor
suppression, and HES1 in acinar cell-derived ADM was
shown to be essential for PanIN formation in mice.11 Both
reports were based on studies on the KrasG12D-driven PDAC
mouse model, but the timing and the cells used for KrasG12D
induction and Hes1 ablation were different.
Given that HES1 is involved in pancreatic development,
our strategy with conditional gene modification in adults
may be more suitable for analyzing pancreatic tumorigenesis. Furthermore, to clarify the roles of HES1 in PDAC
initiation and progression more precisely, it is necessary to
induce Hes1 deletion independently of KrasG12D induction.
However, in Cre-loxP PanIN/PDAC mouse models, it was
impossible to induce Hes1 deletion independently of
KrasG12D induction.

Gastroenterology Vol. 163, No. 6

In the present study, we combined a flippaserecombinase-recombination target and a CreERT2-loxP
recombination system16 to generate a dual-recombinase
mouse model for conditional Hes1 deletion in the adult
pancreas at various stages of tumor development independent of mutant Kras induction. Using this dual-recombinase
mouse model, we confirmed that HES1 is not required for
the maintenance of the adult pancreas under normal settings, but is indispensable for regeneration after caeruleininduced acute pancreatitis. With respect to tumor development, we found that the loss of Hes1 expression suppresses PanIN formation; however, once PanINs develop,
the loss of Hes1 expression promotes tumor progression.
Collectively, our data indicate the context-dependent roles
of Hes1 in the adult pancreas as well as in pancreatic tumor
formation.

Methods
Mice
The generation of Hes1 flox mice (generously provided by
Ryoichiro Kageyama, Institute for Virus Research, Kyoto University, Kyoto, Japan),17 LSL-KrasG12D mice (The Jackson Laboratory, Bar Harbor, ME),18 FSF-KrasG12D mice,16 Pdx1-Flp
mice,16 FSF-R26CAG
CreERT2 mice,16 Trp53frt/þ mice,19 and
Hnf1b-CreERT2 mice (generously provided by Jorge Ferrer,
Imperial College, London, United Kingdom)20 has been reported previously. ...

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