R-spondin1/Wnt-enhanced Ascl2 autoregulation controls the self-renewal of colorectal cancer progenitor cells.
Cell Cycle
; 17(8): 1014-1025, 2018.
Article
en En
| MEDLINE
| ID: mdl-29886802
ABSTRACT
The Wnt signaling pathway controls stem cell identity in the intestinal epithelium and cancer stem cells (CSCs). The transcription factor Ascl2 (Wnt target gene) is fate decider of intestinal cryptic stem cells and colon cancer stem cells. It is unclear how Wnt signaling is translated into Ascl2 expression and keeping the self-renewal of CRC progenitor cells. We showed that the exogenous Ascl2 in colorectal cancer (CRC) cells activated the endogenous Ascl2 expression via a direct autoactivatory loop, including Ascl2 binding to its own promoter and further transcriptional activation. Higher Ascl2 expression in human CRC cancerous tissues led to greater enrichment in Ascl2 immunoprecipitated DNA within the Ascl2 promoter in the CRC cancerous sample than the peri-cancerous mucosa. Ascl2 binding to its own promoter and inducing further transcriptional activation of the Ascl2 gene was predominant in the CD133+CD44+ CRC population. R-spondin1/Wnt activated Ascl2 expression dose-dependently in the CD133+CD44+ CRC population, but not in the CD133-CD44- CRC population, which was caused by differences in Ascl2 autoregulation under R-spondin1/Wnt activation. R-spondin1/Wnt treatment in the CD133+CD44+ or CRC CD133-CD44- populations exerted a different pattern of stemness maintenance, which was defined by alterations of the mRNA levels of stemness-associated genes, the protein expression levels (Bmi1, C-myc, Oct-4 and Nanog) and tumorsphere formation. The results indicated that Ascl2 autoregulation formed a transcriptional switch that was enhanced by Wnt signaling in the CD133+CD44+ CRC population, thus conferring their self-renewal.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Células Madre Neoplásicas
/
Neoplasias del Colon
/
Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico
/
Autorrenovación de las Células
/
Homeostasis
Tipo de estudio:
Prognostic_studies
Límite:
Humans
Idioma:
En
Revista:
Cell Cycle
Año:
2018
Tipo del documento:
Article
País de afiliación:
China