Cancer Letters

Cancer Letters

Volume 423, 1 June 2018, Pages 71-79
Cancer Letters

Original Articles
Pancreatic DCLK1+ cells originate distinctly from PDX1+ progenitors and contribute to the initiation of intraductal papillary mucinous neoplasm in mice

https://doi.org/10.1016/j.canlet.2018.03.009Get rights and content

Highlights

  • In this manuscript, we investigated the role of DCLK1+ cells in the tumorigenesis of pancreatic IPMN.

  • Using a novel genetically-engineered mouse model for IPMN, we discovered that DCLK1+ cells originated from a cell lineage distinct from pancreatic PDX1+ progenitors.

  • The pancreatic DCLK1+ cells shared the features of tuft cells but were devoid of IPMN tumor biomarkers.

  • This is in contrast to previous publications that DCLK1+ serve as tumor stem cells for PanIN/PDA development.

  • Although DCLK1-positivity doesn't serve as a stem cell marker for IPMNs, DCLK1+ cells are important cellular components of “IPMN niches”, and remain potential targets for future therapies.

Abstract

PanINs and IPMNs are the two most common precursor lesions that can progress to invasive pancreatic ductal adenocarcinoma (PDA). DCLK1 has been identified as a biomarker of progenitor cells in PDA progressed from PanINs. To explore the potential role of DCLK1-expressing cells in the genesis of IPMNs, we compared the incidence of DCLK1-positive cells in pancreatic tissue samples from genetically-engineered mouse models (GEMMs) for IPMNs, PanINs, and acinar to ductal metaplasia by immunohistochemistry and immunofluorescence. Mouse lineage tracing experiments in the IPMN GEMM showed that DCLK1+ cells originated from a cell lineage distinct from PDX1+ progenitors. The DCLK1+ cells shared the features of tuft cells but were devoid of IPMN tumor biomarkers. The DCLK1+ cells were detected in the earliest proliferative acinar clusters prior to the formation of metaplastic ductal cells, and were enriched in the “IPMN niches”. In summary, DCLK1 labels a unique pancreatic cellular lineage in the IPMN GEMM. The clustering of DCLK1+ cells is an early event in Kras-induced pancreatic tumorigenesis and may contribute to IPMN initiation.

Introduction

Doublecortin CaM kinase-like-1 (DCLK1, previously referred to as DCAMKL-1) is originally identified in the developing nervous system [1,2]. Its expression is one of the molecular features of gastrointestinal tuft cells [3,4]. DCLK1 regulates the polymerization of microtubules in many mammalian cells by its N-terminal microtubule binding domain [5]. Its C-terminal kinase domain can be cleaved and released from the microtubule anchorage domain by cysteine protease calpain [6]. In addition, DCLK1 has recently been demonstrated as a putative biomarker of tumor-initiating cells in genetically engineered mouse model (GEMMs) for various types of tumors, including pancreatic cancer [[7], [8], [9], [10], [11], [12]]. For example, DCLK1-expressing cells in intestinal tumors have been thought to be tumor progenitor cells, as diphtheria toxin-mediated ablation of DCLK1+ cells led to tumor regression [7,10]. However, in human gastrointestinal tumors, DCLK1-expressing cells were mainly observed at the early stages of tumorigenesis such as metaplastic and hyperplastic lesions [4,13]. Increasing evidence also exhibit that DCLK1 might be a differentiated marker of mature tuft cells in the intestine, rather than a stem or progenitor cell marker in normal and tumor tissues [14,15].

Pancreatic intraductal papillary mucinous neoplasms (IPMN) is one of the three known precursors of invasive pancreatic ductal adenocarcinoma (PDA). High frequency of DCLK1+ cells has been also reported in precursor lesions of pancreatic cancer such as pancreatic intraepithelial neoplasias (PanINs) in both human and mouse [8,[15], [16], [17]]. These morphologically tuft-like DCLK1-expressing cells have been recognized as putative stem/progenitor cells in pancreatic tissues of these GEMMs with PanIN/PDA histologic presentation [18], but how DCLK1+ cells are involved in the genesis of pancreatic IPMNs has not been explored.

TGF-β superfamily signaling plays a pivotal role in determining the pathogenesis of PDA derived from PanINs or IPMNs [[19], [20], [21], [22]]. We have reported that mutant Kras in the context of inactivated activin signaling promotes the development of IPMN/PDA in our recently established Acvr1bflox/flox;LSL-KrasG12D;Pdx1-Cre GEMM [22,23]. In contrast, mPanIN/PDA pathogenesis is the major histologic presentation in the LSL-KrasG12D; Pdx1-Cre GEMM with or without additional p16 inactivation [24,25]. Using these established GEMMs with specific IPMN or PanIN genesis, we observed that DCLK1+ cells were predominately detected in the pancreatic tissues with activated mutant Kras and not in the Cre-negative normal control mice. Pancreatic DCLK1+ cells shared the molecular features of intestinal tuft cells but not the IPMN tumor cells. Lineage tracing demonstrated that these pancreatic DCLK1-expressing cells originated from cell lineage distinct from PDX1+ progenitors. Furthermore, DCLK1+ cells could be detected in the early stage of tumorigenesis, such as in the proliferative acinar clusters prior to the formation of metaplastic ductal cells, and were further enriched at the base of IPMN tumors.

Section snippets

Mouse strains

All animal experiments described here were approved by Columbia University Animal Care and Use Committees. LSL-KrasG12D; Pdx1-Cre (thereafter called KP) mice [24] with full spectrum of PanINs and low progression to invasive PDA were used as the representative PanIN model in this study. Acvr1bflox/flox; LSL-KrasG12D; Pdx1-Cre (thereafter called AKP) mice [22] (backcrossed to C57BL/6 background), a recently characterized GEMM for IPMN, were bred into R26REYFP mice (

DCLK1+ cells significantly accumulated in the precursor lesions of pancreatic tumors

We have previously reported a GEMM for IPMNs (Acvr1bflox/flox;LSL-KrasG12D;Pdx1-Cre or the AKP GEMM) [22] which was generated by tissue-specific and conditional inactivation of the Acvr1b gene (Acvr1bflox/flox) [23] in the pancreas in the context of oncogenic Kras activation (LSL-KrasG12D;Pdx1-Cre or the KP GEMM) [24]. To explore the potential role of DCLK1-expressing cells in the genesis of IPMNs, DCLK1-expressing cells were investigated in the pancreatic tissues of the AKP GEMM by

Discussion

DCLK1+ cells have been previously demonstrated being involved in both intestinal regeneration homeostasis and response to pancreatic inflammatory injury [7,17]. The inflammation-induced regeneration seems to be essential for oncogene-related carcinogenesis [41]. The mechanisms for the interaction between oncogene-induced inflammation and tumorigenesis in pancreas are not clear. In this study, we showed that DCLK1+ cells are mainly enriched in inflammatory lesions ADM and precancerous lesions

Conflicts of interest statement

There is no conflict of interest pertaining to this publication to be disclosed by any of the authors.

Acknowledgements

We want to acknowledge Dr. Jessica Kandel for her generosity of sharing the Rag2−/−;Il2rg−/−;eGFP+/+ immunodeficient mice with us prior to its publication. This study was only possible with the support of the NIH/NCI R01 CA217207, NIH/NCI R01 CA178445.

References (51)

  • J.L. Kopp et al.

    Identification of Sox9-dependent acinar-to-ductal reprogramming as the principal mechanism for initiation of pancreatic ductal adenocarcinoma

    Canc. Cell

    (2012)
  • O. Strobel et al.

    Pancreatic duct glands are distinct ductal compartments that react to chronic injury and mediate Shh-induced metaplasia

    Gastroenterology

    (2010)
  • H. Kuniyasu et al.

    Induction of angiogenesis by hyperplastic colonic mucosa adjacent to colon cancer

    Am. J. Pathol.

    (2000)
  • K. Takahashi et al.

    Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors

    Cell

    (2006)
  • C. Guerra et al.

    Chronic pancreatitis is essential for induction of pancreatic ductal adenocarcinoma by K-Ras oncogenes in adult mice

    Canc. Cell

    (2007)
  • D. Wei et al.

    KLF4 is essential for induction of cellular identity change and acinar-to-ductal reprogramming during early pancreatic carcinogenesis

    Canc. Cell

    (2016)
  • Y. Mori-Akiyama et al.

    SOX9 is required for the differentiation of paneth cells in the intestinal epithelium

    Gastroenterology

    (2007)
  • Y. Omori et al.

    Expression and chromosomal localization of KIAA0369, a putative kinase structurally related to Doublecortin

    J. Hum. Genet.

    (1998)
  • P.T. Lin et al.

    DCAMKL1 encodes a protein kinase with homology to doublecortin that regulates microtubule polymerization

    J. Neurosci.

    (2000)
  • M. Saqui-Salces et al.

    Gastric tuft cells express DCLK1 and are expanded in hyperplasia

    Histochem. Cell Biol.

    (2011)
  • V. des Portes et al.

    A novel CNS gene required for neuronal migration and involved in X-linked subcortical laminar heterotopia and lissencephaly syndrome

    Cell

    (1998)
  • C.B. Westphalen et al.

    Long-lived intestinal tuft cells serve as colon cancer-initiating cells

    J. Clin. Invest.

    (2014 Mar)
  • S.M. Sureban et al.

    Selective blockade of DCAMKL-1 results in tumor growth arrest by a Let-7a MicroRNA-dependent mechanism

    Gastroenterology

    (2009)
  • Y. Nakanishi et al.

    Dclk1 distinguishes between tumor and normal stem cells in the intestine

    Nat. Genet.

    (2013)
  • R. May et al.

    Identification of a novel putative gastrointestinal stem cell and adenoma stem cell marker, doublecortin and CaM kinase-like-1, following radiation injury and in adenomatous polyposis coli/multiple intestinal neoplasia mice

    Stem Cell.

    (2008)
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