RESUMO
Sox2 expression marks gastric stem and progenitor cells, raising important questions regarding the genes regulated by Sox2 and the role of Sox2 itself during stomach homeostasis and disease. By using ChIP-seq analysis, we have found that the majority of Sox2 targets in gastric epithelial cells are tissue specific and related to functions such as endoderm development, Wnt signaling, and gastric cancer. Unexpectedly, we found that Sox2 itself is dispensable for gastric stem cell and epithelial self-renewal, yet Sox2(+) cells are highly susceptible to tumorigenesis in an Apc/Wnt-driven mouse model. Moreover, Sox2 loss enhances, rather than impairs, tumor formation in Apc-deficient gastric cells in vivo and in vitro by inducing Tcf/Lef-dependent transcription and upregulating intestinal metaplasia-associated genes, providing a mechanistic basis for the observed phenotype. Together, these data identify Sox2 as a context-dependent tumor suppressor protein that is dispensable for normal tissue regeneration but restrains stomach adenoma formation through modulation of Wnt-responsive and intestinal genes.
Assuntos
Adenoma/genética , Proteína da Polipose Adenomatosa do Colo/genética , Transformação Celular Neoplásica/genética , Regulação Neoplásica da Expressão Gênica , Fatores de Transcrição SOXB1/genética , Neoplasias Gástricas/genética , Adenoma/metabolismo , Adenoma/patologia , Proteína da Polipose Adenomatosa do Colo/deficiência , Animais , Sequência de Bases , Linhagem Celular Tumoral , Proliferação de Células , Transformação Celular Neoplásica/metabolismo , Transformação Celular Neoplásica/patologia , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Fator 1-alfa Nuclear de Hepatócito/genética , Fator 1-alfa Nuclear de Hepatócito/metabolismo , Fator 1 de Ligação ao Facilitador Linfoide/genética , Fator 1 de Ligação ao Facilitador Linfoide/metabolismo , Camundongos , Camundongos Transgênicos , Fatores de Transcrição SOXB1/metabolismo , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/patologia , Via de Sinalização WntRESUMO
The transcription factor Sox2 maintains the pluripotency of early embryonic cells and regulates the formation of several epithelia during fetal development. Whether Sox2 continues to play a role in adult tissues remains largely unknown. We show here that Sox2 marks adult cells in several epithelial tissues where its expression has not previously been characterized, including the stomach, cervix, anus, testes, lens, and multiple glands. Genetic lineage tracing and transplantation experiments demonstrate that Sox2-expressing cells continuously give rise to mature cell types within these tissues, documenting their self-renewal and differentiation potentials. Consistent with these findings, ablation of Sox2(+) cells in mice results in a disruption of epithelial tissue homeostasis and lethality. Developmental fate mapping reveals that Sox2(+) adult stem cells originate from fetal Sox2(+) tissue progenitors. Thus, our results identify Sox2 expression in numerous adult endodermal and ectodermal stem cell compartments, which are critical for normal tissue regeneration and survival.