Chapter Ten - The Central Role of Wnt Signaling and Organoid Technology in Personalizing Anticancer Therapy

https://doi.org/10.1016/bs.pmbts.2017.11.009Get rights and content

Abstract

The Wnt pathway is at the heart of organoid technology, which is set to revolutionize the cancer field. We can now predetermine a patient's response to any given anticancer therapy by exposing tumor organoids established from the patient's own tumor. This cutting-edge biomedical platform translates to patients being treated with the correct drug at the correct dose from the outset, a truly personalized and precise medical approach. A high throughput drug screen on organoids also allows drugs to be tested in limitless combinations. More recently, the tumor cells that are resistant to the therapy given to a patient were selected in culture using the patient's organoids. The resistant tumor organoids were then screened empirically to identify drugs that will kill the resistant cells. This information allows diagnosis in real-time to either prevent tumor recurrence or effectively treat the recurring tumor. Furthermore, the ability to culture stem cell-derived epithelium as organoids has enabled us to begin to understand how a stem cell becomes a cancer cell or to pin-point the genetic alteration that underlies a given genetic syndrome. Here we summarize these advances and the central role of Wnt signaling, and identify the next challenges for organoid technology.

Introduction

Stem cell-derived three-dimensional (3D) replicas of organs grown in tissue culture, termed organoids, have led to remarkable advances in stem cell and developmental biology, human disease, and regenerative medicine.1 “Organoid” is a term originally used by developmental biologists working with tissue explants to unravel the mechanisms of organogenesis. The term literally means “organ-like.” More recent use of the term organoid is defined as a 3D structure established from stem cells and consisting of organ-specific cell types that self-organize to mimic their tissue of origin.2, 3 Organoids can be initiated from two main types of stem cells (summarized in Table 1). The first stem cell type is the pluripotent embryonic stem (ES) cell or the induced pluripotent stem cell (iPS). For iPS, adult cells are artificially reprogrammed to pluripotency,4 and then differentiated toward different organ cell types using cues that have been identified to orchestrate the development of those organs during embryogenesis and organogenesis.3, 5 Diverse tissue and organ cell types can be derived from a pluripotent stem cell.

By contrast, the second type of stem cells, the tissue restricted adult stem cells, have a “memory” of their tissue of origin and self-organize and differentiate into structures that contain the different tissue-specific cell types; they recapitulate the characteristics of tissue function and architecture.1 The culture conditions that were developed to establish adult tissue stem cell-derived organoids were then adapted to growing organoids from diseased tissues, such as cancers (Table 1). This innovation has led to one of the most important advances in cancer research—high throughput drug prescreening, in a clinically relevant time frame, on patient-derived tumor organoids to personalize treatment.6, 7 In this chapter we briefly summarize the discoveries that led to adult stem-cell-derived organoid technology, the central role of Wnt signaling in this advance and how this advance is poised to revolutionize anticancer treatment. We also highlight the next challenges for patient-derived tumor organoid technology in the quest for curative anticancer treatment. Improved survival is clearly a great outcome for anticancer treatment, but the ultimate goal is curative treatment where the tumor cells are eliminated.

Section snippets

WNT signaling pathway

The Wnt signal transduction pathway has several branches that are β-catenin-dependent and β-catenin-independent (i.e., the calcium and planar cell polarity pathways) and the core components of these are highly conserved through evolution.8, 9 Here we give a brief overview of the Wnt/β-catenin branch10 as it is critical to stem cell function and organoid formation. In the absence of a Wnt ligand, β-catenin is primarily engaged in cell-cell adherens junctions. Any free newly synthesized β-catenin

Organoids derived from adult epithelium

Adult stem cell-derived organoids were first established from the epithelium lining the mouse intestine.26 Several discoveries led to this game-changing achievement. The first was the demonstration in 1998 by Korinek and coworkers that Wnt signaling is critical for intestinal stem cells. Deletion of the gene that codes for Tcf4, the downstream effector of Wnt signaling (Fig. 1), from the developing mouse intestine led to a depletion of the putative epithelial stem cell compartment and postnatal

Organoids derived from patient tumors

Once the culture techniques for growing intestinal organoids were established, variations on the same culture protocol led to the establishment of organoids from several other gastrointestinal tissues,41, 48 as well as many other stem-cell maintained adult tissues (several comprehensive recent reviews49, 50, 51). Clevers and coworkers also adapted the organoid protocols to grow patient-derived colon cancer tumor organoids. The mini-tumor organoids similarly recapitulate the features of actively

Modeling dormant tumor cells: the next frontier for tumor organoids

One limitation for mini-tumor organoids as a drug screen is that the ever-expanding tumor organoids mimic the actively growing tumor cells. The mini-tumor organoids do not mimic the dormant tumor cell state. The key to curative cancer treatment is to therapeutically target and eliminate the disseminated dormant tumor cells that eventually reestablish tumors at secondary sites and are ultimately the cause of death. Some therapies will target actively dividing, as well as dormant tumor cells; but

Conclusions

In this chapter we have tried to highlight the current state of the tumor organoid field, which is advancing at an astronomical rate. Mini-gut and mini-tumor organoids have revolutionized our understanding of the molecular mechanisms that underlie transition from normal epithelial stem cell to cancer cell, identify the molecular drivers of cancer cells, and predict their susceptibility to anticancer drugs. The ability to conduct drug screens on dormant patient tumor cells is the next frontier

Acknowledgments

We thank Gavin Mitchell for generating the artwork, and Nancy Amin and Jordane Malaterre for the confocal images. Funding is gratefully acknowledged from the National Health and Medical Research Council of Australia (566679 & APP1099302); Melbourne Health project grants (605030 & PG-002) and early career researcher grant (GIA-033); Cancer Council Victoria project grant (APP1020716) and Fellowship; and Cardiff University.

References (97)

  • T. Sato et al.

    Long-term expansion of epithelial organoids from human colon, adenoma, adenocarcinoma, and Barrett's epithelium

    Gastroenterology

    (2011)
  • G. Schwank et al.

    Functional repair of CFTR by CRISPR/Cas9 in intestinal stem cell organoids of cystic fibrosis patients

    Cell Stem Cell

    (2013)
  • D.J. Flanagan et al.

    Frizzled7 functions as a Wnt receptor in intestinal epithelium stem cells

    Stem Cell Reports

    (2015)
  • K.R. Levental et al.

    Matrix crosslinking forces tumor progression by enhancing integrin signaling

    Cell

    (2009)
  • D. Dutta et al.

    Disease modeling in stem cell-derived 3D organoid systems

    Trends Mol Med

    (2017)
  • H. Clevers et al.

    Wnt/beta-catenin signaling and disease

    Cell

    (2012)
  • E.R. Fearon et al.

    A genetic model for colorectal tumorigenesis

    Cell

    (1990)
  • Y. Ding et al.

    Wnt signal transduction: kinase cogs in a nano-machine?

    Trends Biochem Sci

    (2002)
  • A. Dimitriadis et al.

    Expression of Wnt genes in human colon cancers

    Cancer Lett

    (2001)
  • T. Brabletz et al.

    Nuclear overexpression of the oncoprotein beta-catenin in colorectal cancer is localized predominantly at the invasion front

    Pathol Res Pract

    (1998)
  • N. Lugli et al.

    Enhanced rate of acquisition of point mutations in mouse intestinal adenomas compared to normal tissue

    Cell Rep

    (2017)
  • A. Cristobal et al.

    Personalized proteome profiles of healthy and tumor human colon organoids reveal both individual diversity and basic features of colorectal cancer

    Cell Rep

    (2017)
  • K.R. Kao et al.

    The legacy of lithium effects on development

    Biol Cell

    (1998)
  • E. Vincan et al.

    Frizzled-7 receptor ectodomain expression in a colon cancer cell line induces morphological change and attenuates tumor growth

    Differentiation

    (2005)
  • J.B. Gurdon

    Adult frogs derived from the nuclei of single somatic cells

    Dev Biol

    (1962)
  • M.A. Lancaster et al.

    Organogenesis in a dish: modeling development and disease using organoid technologies

    Science

    (2014)
  • Y. Shi et al.

    Induced pluripotent stem cell technology: a decade of progress

    Nat Rev Drug Discov

    (2017)
  • T. Phesse et al.

    Frizzled7: a promising achilles' heel for targeting the Wnt receptor complex to treat cancer

    Cancers

    (2016)
  • C. Niehrs

    The complex world of WNT receptor signalling

    Nat Rev Mol Cell Biol

    (2012)
  • D.L. Daniels et al.

    Beta-catenin directly displaces Groucho/TLE repressors from Tcf/Lef in Wnt-mediated transcription activation

    Nat Struct Mol Biol

    (2005)
  • J.H. van Es et al.

    Wnt signalling induces maturation of Paneth cells in intestinal crypts

    Nat Cell Biol

    (2005)
  • V. Korinek et al.

    Depletion of epithelial stem-cell compartments in the small intestine of mice lacking Tcf-4

    Nat Genetics

    (1998)
  • N. Barker et al.

    Identification of stem cells in small intestine and colon by marker gene Lgr5

    Nature

    (2007)
  • C. Albuquerque et al.

    The “just-right” signaling model: APC somatic mutations are selected based on a specific level of activation of the beta-catenin signaling cascade

    Hum Mol Genetics

    (2002)
  • E. Driehuis et al.

    WNT signalling events near the cell membrane and their pharmacological targeting for the treatment of cancer

    Br J Pharmacol

    (2017)
  • T. Brabletz et al.

    Variable beta-catenin expression in colorectal cancers indicates tumor progression driven by the tumor environment

    Proc Natl Acad Sci USA

    (2001)
  • T. Brabletz et al.

    Opinion: migrating cancer stem cells—an integrated concept of malignant tumour progression

    Nat Rev Cancer

    (2005)
  • E. Vincan et al.

    The upstream components of the Wnt signalling pathway in the dynamic EMT and MET associated with colorectal cancer progression

    Clin Exp Metastasis

    (2008)
  • G.M. Caldwell et al.

    The Wnt antagonist sFRP1 in colorectal tumorigenesis

    Cancer Res

    (2004)
  • G.M. Caldwell et al.

    The Wnt antagonist sFRP1 is downregulated in premalignant large bowel adenomas

    Br J Cancer

    (2006)
  • H. Suzuki et al.

    Epigenetic inactivation of SFRP genes allows constitutive WNT signaling in colorectal cancer

    Nat Genetics

    (2004)
  • H. Taniguchi et al.

    Frequent epigenetic inactivation of Wnt inhibitory factor-1 in human gastrointestinal cancers

    Oncogene

    (2005)
  • O. Aguilera et al.

    Epigenetic inactivation of the Wnt antagonist DICKKOPF-1 (DKK-1) gene in human colorectal cancer

    Oncogene

    (2006)
  • T. Sato et al.

    Single Lgr5 stem cells build crypt-villus structures in vitro without a mesenchymal niche

    Nature

    (2009)
  • D. Pinto et al.

    Canonical Wnt signals are essential for homeostasis of the intestinal epithelium

    Genes Dev

    (2003)
  • F. Kuhnert et al.

    Essential requirement for Wnt signaling in proliferation of adult small intestine and colon revealed by adenoviral expression of Dickkopf-1

    Proc Natl Acad Sci USA

    (2004)
  • T. Sato et al.

    Paneth cells constitute the niche for Lgr5 stem cells in intestinal crypts

    Nature

    (2011)
  • H.F. Farin et al.

    Redundant sources of wnt regulate intestinal stem cells and promote formation of paneth cells

    Gastroenterology

    (2012)
  • View full text