Abstract

Pancreatic intraepithelial neoplasia is a pre-malignant lesion that can progress to pancreatic ductal adenocarcinoma, a highly lethal malignancy marked by its late stage at clinical presentation and profound drug resistance1. The genomic alterations that commonly occur in pancreatic cancer include activation of KRAS2 and inactivation of p53 and SMAD4 (refs 2, 3, 4). So far, however, it has been challenging to target these pathways therapeutically; thus the search for other key mediators of pancreatic cancer growth remains an important endeavour. Here we show that the stem cell determinant Musashi (Msi) is a critical element of pancreatic cancer progression both in genetic models and in patient-derived xenografts. Specifically, we developed Msi reporter mice that allowed image-based tracking of stem cell signals within cancers, revealing that Msi expression rises as pancreatic intraepithelial neoplasia progresses to adenocarcinoma, and that Msi-expressing cells are key drivers of pancreatic cancer: they preferentially harbour the capacity to propagate adenocarcinoma, are enriched in circulating tumour cells, and are markedly drug resistant. This population could be effectively targeted by deletion of either Msi1 or Msi2, which led to a striking defect in the progression of pancreatic intraepithelial neoplasia to adenocarcinoma and an improvement in overall survival. Msi inhibition also blocked the growth of primary patient-derived tumours, suggesting that this signal is required for human disease. To define the translational potential of this work we developed antisense oligonucleotides against Msi; these showed reliable tumour penetration, uptake and target inhibition, and effectively blocked pancreatic cancer growth. Collectively, these studies highlight Msi reporters as a unique tool to identify therapy resistance, and define Msi signalling as a central regulator of pancreatic cancer.

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Primary accessions

Gene Expression Omnibus

Data deposits

Microarray and RNA-seq data have been deposited in the Gene Expression Omnibus under accession numbers GSE73312 and GSE75797.

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Acknowledgements

We are grateful to I. Verma, M. Karin, and D. Cheresh for advice and comments on the manuscript, A. Luo and T. Wang for technical support, G. Yeo for advice on Msi targeting, K. Jenne for advice on MRI imaging, N. Patel and P. Mischel for reagents and experimental advice, and E. O’Conner and K. Marquez for cell sorting. R.F. is a recipient of a California Institute for Regenerative Medicine interdisciplinary stem cell training program fellowship and received support from T32 HL086344 and T32 CA009523, C.K. received support from T32 GM007752, N.K.L. received support from T32 GM007752 and a National Research Service Award F31 CA206416, J.L.K. received support from National Institutes of Health (NIH)-F32CA136124 and an Advanced Postdoctoral Fellowship from the Juvenile Diabetes Research Foundation, and B.Z. received support from T32 GM007184-33 (Duke University). F.P. is a recipient of a California Institute for Regenerative Medicine interdisciplinary stem cell training program fellowship and the University of California San Diego Clinical and Translational Research Institute KL2 Award. T.I. is the recipient of a California Institute for Regenerative Medicine interdisciplinary stem cell training program fellowship, J.B. is supported by a postdoctoral fellowship from National Cancer Center, and T.R. was supported in part by a Leukemia and Lymphoma Society Scholar Award. P.M.G. and M.A.H. are supported by a Specialized Program of Research Excellence (SPORE) in Pancreatic Cancer, CA127297, a TMEN Tumor Microenvironment Network U54, a National Cancer Institute Cancer Center Support Grant P30 CA36727, and an Early Detection Research Network (EDRN) U01 CA111294, M.Sa. is supported by NIH DK078803 and NIH CA194839, J.K.S. is supported by NIH K08CA168999, R.S. is supported by the Clinical and Translational Research Institute (CTRI) grant UL1TR001442, and A.M.L. is supported by donations from Ride the Point. This work was also supported by CA155620 to A.M.L., DK63031, HL097767, DP1 CA174422, and R35 CA197699 to T.R., and CA186043 to A.M.L. and T.R.

Author information

Author notes

    • Raymond G. Fox
    •  & Nikki K. Lytle

    These authors contributed equally to this work.

    • Masato Yano

    Present address: Division of Neurobiology and Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Asahimachidori, Chuo-ku, Niigata 951-8510, Japan.

Affiliations

  1. Department of Pharmacology, University of California San Diego School of Medicine La Jolla, California 92093, USA

    • Raymond G. Fox
    • , Nikki K. Lytle
    • , Frederick D. Park
    • , Takahiro Ito
    • , Jeevisha Bajaj
    • , Claire S. Koechlein
    • , Bryan Zimdahl
    • , Marcie Kritzik
    •  & Tannishtha Reya
  2. Department of Medicine, University of California San Diego School of Medicine La Jolla, California 92093, USA

    • Raymond G. Fox
    • , Nikki K. Lytle
    • , Frederick D. Park
    • , Takahiro Ito
    • , Jeevisha Bajaj
    • , Claire S. Koechlein
    • , Bryan Zimdahl
    • , Marcie Kritzik
    •  & Tannishtha Reya
  3. Sanford Consortium for Regenerative Medicine, La Jolla, California 92037, USA

    • Raymond G. Fox
    • , Nikki K. Lytle
    • , Frederick D. Park
    • , Takahiro Ito
    • , Jeevisha Bajaj
    • , Claire S. Koechlein
    • , Bryan Zimdahl
    • , Janel L. Kopp
    • , Marcie Kritzik
    • , Maike Sander
    •  & Tannishtha Reya
  4. Moores Cancer Center, University of California San Diego School of Medicine, La Jolla, California 92093, USA

    • Raymond G. Fox
    • , Nikki K. Lytle
    • , Dawn V. Jaquish
    • , Frederick D. Park
    • , Takahiro Ito
    • , Jeevisha Bajaj
    • , Claire S. Koechlein
    • , Bryan Zimdahl
    • , Marcie Kritzik
    • , Jason K. Sicklick
    • , Andrew M. Lowy
    •  & Tannishtha Reya
  5. Department of Surgery, Division of Surgical Oncology, University of California San Diego School of Medicine, La Jolla, California 92093, USA

    • Dawn V. Jaquish
    • , Jason K. Sicklick
    •  & Andrew M. Lowy
  6. Department of Medicine, Division of Gastroenterology, University of California San Diego School of Medicine, La Jolla, California 92093, USA

    • Frederick D. Park
  7. Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan

    • Masato Yano
    • , Shinsuke Shibata
    •  & Hideyuki Okano
  8. Department of Cellular and Molecular Medicine, University of California San Diego School of Medicine, La Jolla, California 92093, USA

    • Janel L. Kopp
    •  & Maike Sander
  9. Eppley Institute for Research in Cancer and Allied Diseases, Department of Pathology, University of Nebraska Medical Center, Omaha, Nebraska 68198, USA

    • Paul M. Grandgenett
    •  & Michael A. Hollingsworth
  10. Department of Pathology, University of California San Diego School of Medicine, La Jolla, California 92093, USA

    • Donald Pizzo
    •  & Mark A. Valasek
  11. Center for Computational Biology and Bioinformatics, University of California San Diego School of Medicine, La Jolla, California 92093, USA

    • Roman Sasik
  12. Department of Radiology, University of California San Diego School of Medicine, La Jolla, California 92093, USA

    • Miriam Scadeng
  13. Department of Oncology Drug Discovery, Ionis Pharmaceuticals, Carlsbad, California 92010, USA

    • Youngsoo Kim
    •  & A. Robert MacLeod

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Contributions

R.F. designed and performed all experiments related to Msi expression and deletion, whole genome and target analysis, and ASO delivery in pancreatic cancer; N.K.L. designed and performed all live imaging of Msi reporter pancreatic tumours, and provided functional analysis of cancer stem cells, circulating tumour cells, and therapy resistance; R.F., N.K.L., and M.K. helped write the paper; D.V.J. performed histological analysis, and provided mouse and xenograft models; F.P., T.I., J.B., C.K., and B.Z. provided experimental data and advice; R.S. performed all bioinformatics analysis; M.Y., S.S., and H.O. provided Msi1−/− mice and CLIP-seq analysis; M.V. and D.P. performed pathology/in situ hybridization analysis; M.Sc. performed MRI analysis; J.K. and M. Sa. provided experimental advice, tumour samples, and mouse models; J.S., A.M.L., M.V., P.A.G., and M.A.H. provided patient samples; Y.K. and R.M. designed, synthesized, and screened MSI ASOs, and provided advice on ASO-related experiments. A.M.L. and T.R. conceived the project, planned and guided the research, and wrote the paper.

Competing interests

T.I. and T.R. are named inventors on a patent application number 61/178,370 titled ‘Diagnostic and treatment for chronic and acute myeloid leukemia’. Y.K. and A.R.M. are employees and shareholders of Ionis Pharmaceuticals.

Corresponding authors

Correspondence to Andrew M. Lowy or Tannishtha Reya.

Extended data

Supplementary information

Videos

  1. 1.

    Live imaging of tumor bearing REM2-KPf/fC mouse

    4D view of Msi2 reporter+ pancreatic cancer cells within tumor mass. VE-cadherin (magenta), Hoechst (blue) and Msi2 reporter (green).

  2. 2.

    MRI of wild type mouse

    3-D projection of MRI image from control mouse with normal pancreas.

  3. 3.

    MRI of WT-KPf/fC mouse

    3-D projection of MRI image from WT-KPf/fC mouse (11 weeks)

  4. 4.

    MRI of Msi1-/--KPf/fC mouse

    3-D projection of MRI image from Msi1-/--KPf/fC mouse (11 weeks)

  5. 5.

    MRI of WT-KPf/fC mouse

    3-D projection of MRI image from WT-KPf/fC mouse, (13 weeks)

  6. 6.

    MRI of Msi2-/--KPf/fC mouse

    3-D projection of MRI image from Msi2-/--KPf/fC mouse, (13 weeks)

About this article

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DOI

https://doi.org/10.1038/nature17988

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