BHLHA15-Positive Secretory Precursor Cells Can Give Rise to Tumors in Intestine and Colon in Mice

Gastroenterology. 2019 Mar;156(4):1066-1081.e16. doi: 10.1053/j.gastro.2018.11.024. Epub 2018 Nov 15.

Abstract

Background & aims: The intestinal epithelium is maintained by long-lived intestinal stem cells (ISCs) that reside near the crypt base. Above the ISC zone, there are short-lived progenitors that normally give rise to lineage-specific differentiated cell types but can dedifferentiate into ISCs in certain circumstances. However, the role of epithelial dedifferentiation in cancer development has not been fully elucidated.

Methods: We performed studies with Bhlha15-CreERT, Lgr5-DTR-GFP, Apcflox/flox, LSL-Notch (IC), and R26-reporter strains of mice. Some mice were given diphtheria toxin to ablate Lgr5-positive cells, were irradiated, or were given 5-fluorouracil, hydroxyurea, doxorubicin, or dextran sodium sulfate to induce intestinal or colonic tissue injury. In intestinal tissues, we analyzed the fate of progeny that expressed Bhlha15. We used microarrays and reverse-transcription PCR to analyze gene expression patterns in healthy and injured intestinal tissues and in tumors. We analyzed gene expression patterns in human colorectal tumors using The Cancer Genome Atlas data set.

Results: Bhlha15 identified Paneth cells and short-lived secretory precursors (including pre-Paneth label-retaining cells) located just above the ISC zone in the intestinal epithelium. Bhlha15+ cells had no plasticity after loss of Lgr5-positive cells or irradiation. However, Bhlha15+ secretory precursors started to supply the enterocyte lineage after doxorubicin-induced epithelial injury in a Notch-dependent manner. Sustained activation of Notch converts Bhlha15+ secretory precursors to long-lived enterocyte progenitors. Administration of doxorubicin and expression of an activated form of Notch resulted in a gene expression pattern associated with enterocyte progenitors, whereas only sustained activation of Notch altered gene expression patterns in Bhlha15+ precursors toward those of ISCs. Bhlha15+ enterocyte progenitors with sustained activation of Notch formed intestinal tumors with serrated features in mice with disruption of Apc. In the colon, Bhlha15 marked secretory precursors that became stem-like, cancer-initiating cells after dextran sodium sulfate-induced injury, via activation of Src and YAP signaling. In analyses of human colorectal tumors, we associated activation of Notch with chromosome instability-type tumors with serrated features in the left colon.

Conclusions: In mice, we found that short-lived precursors can undergo permanent reprogramming by activation of Notch and YAP signaling. These cells could mediate tumor formation in addition to traditional ISCs.

Keywords: Colon Cancer; Interconversion; Tumorigenesis; Yes Associated Protein 1.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism
  • Animals
  • Antibiotics, Antineoplastic / pharmacology
  • Antineoplastic Agents, Hormonal / pharmacology
  • Basic Helix-Loop-Helix Transcription Factors / genetics
  • Basic Helix-Loop-Helix Transcription Factors / metabolism*
  • CD24 Antigen / metabolism
  • Calcium-Binding Proteins
  • Cell Cycle Proteins
  • Cell Plasticity
  • Chromogranin A / genetics
  • Colonic Neoplasms / genetics*
  • Colonic Neoplasms / metabolism
  • Colonic Neoplasms / pathology
  • Doxorubicin / pharmacology
  • Enterocytes / metabolism
  • Enterocytes / pathology*
  • Gene Expression
  • Gene Expression Profiling
  • Intercellular Signaling Peptides and Proteins / genetics
  • Intestinal Mucosa / drug effects
  • Intestinal Mucosa / metabolism*
  • Intestinal Mucosa / pathology
  • Intestine, Small / cytology
  • Intestine, Small / metabolism
  • Mice
  • Neoplasm Proteins / genetics
  • Neoplastic Stem Cells / drug effects
  • Neoplastic Stem Cells / metabolism
  • Pancreatitis-Associated Proteins
  • Paneth Cells
  • Phosphoproteins / metabolism
  • Proto-Oncogene Proteins c-kit / metabolism
  • Receptors, G-Protein-Coupled / metabolism
  • Receptors, Notch / metabolism*
  • Signal Transduction
  • Stem Cells / drug effects
  • Stem Cells / metabolism*
  • Stem Cells / physiology
  • Stem Cells / radiation effects
  • Tamoxifen / pharmacology
  • Transcriptome*
  • src-Family Kinases / metabolism

Substances

  • Adaptor Proteins, Signal Transducing
  • Antibiotics, Antineoplastic
  • Antineoplastic Agents, Hormonal
  • Atoh1 protein, mouse
  • Basic Helix-Loop-Helix Transcription Factors
  • Bhlha15 protein, mouse
  • CD24 Antigen
  • Calcium-Binding Proteins
  • Cd24a protein, mouse
  • Cell Cycle Proteins
  • Chromogranin A
  • Dlk1 protein, mouse
  • Intercellular Signaling Peptides and Proteins
  • Lgr5 protein, mouse
  • Neoplasm Proteins
  • Pancreatitis-Associated Proteins
  • Phosphoproteins
  • REG4 protein, mouse
  • Receptors, G-Protein-Coupled
  • Receptors, Notch
  • Yap1 protein, mouse
  • chromogranin A, mouse
  • Tamoxifen
  • Doxorubicin
  • Proto-Oncogene Proteins c-kit
  • src-Family Kinases