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Conversion of Helicobacter pylori CagA from senescence inducer to oncogenic driver through polarity-dependent regulation of p21

The Helicobacter pylori CagA bacterial oncoprotein plays a critical role in gastric carcinogenesis. Upon delivery into epithelial cells, CagA causes loss of polarity and activates aberrant Erk signaling. We show that CagA-induced Erk activation results in senescence and mitogenesis in nonpolarized a...

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Detalles Bibliográficos
Autores principales: Saito, Yasuhiro, Murata-Kamiya, Naoko, Hirayama, Toshiya, Ohba, Yusuke, Hatakeyama, Masanori
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 2010
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2947069/
https://www.ncbi.nlm.nih.gov/pubmed/20855497
http://dx.doi.org/10.1084/jem.20100602
Descripción
Sumario:The Helicobacter pylori CagA bacterial oncoprotein plays a critical role in gastric carcinogenesis. Upon delivery into epithelial cells, CagA causes loss of polarity and activates aberrant Erk signaling. We show that CagA-induced Erk activation results in senescence and mitogenesis in nonpolarized and polarized epithelial cells, respectively. In nonpolarized epithelial cells, Erk activation results in oncogenic stress, up-regulation of the p21(Waf1/Cip1) cyclin-dependent kinase inhibitor, and induction of senescence. In polarized epithelial cells, CagA-driven Erk signals prevent p21(Waf1/Cip1) expression by activating a guanine nucleotide exchange factor–H1–RhoA–RhoA-associated kinase–c-Myc pathway. The microRNAs miR-17 and miR-20a, induced by c-Myc, are needed to suppress p21(Waf1/Cip1) expression. CagA also drives an epithelial-mesenchymal transition in polarized epithelial cells. These findings suggest that CagA exploits a polarity-signaling pathway to induce oncogenesis.