title: miR-21 and let-7 in the Ras and NF-κB pathways.
abstract: miR-21 and let-7 are two of the most studied microRNAs (miRNAs), as the former is the most frequently upregulated and the latter is the most frequently down-regulated in cancer. In this short essay, we examine the convergence of miR-21 and let-7 in two major cancer pathways: Ras and NF-κB. miR-21 suppresses multiple targets to enhance the oncogenic action of Ras, while let-7 is a direct negative regulator of the Ras gene family. let-7 is proposed to repress the activation of NF-κB through down-regulation of Ras and IL-6, while miR-21 is demonstrated to enhance NF-κB activation by down-regulating Pten and thereby increasing the activity of Akt, a kinase known to promote the NF-κB pathway. Therefore, miR-21 and let-7 contravene each other in cancer and simultaneous targeting of both is an attractive therapeutic strategy against cancers exhibiting both Ras mutations and constitutive NF-κB activation.
authors.forename: Saibyasachi N
authors.initials: SN
authors.lastname: Choudhury
authors.affiliation: Department of Biochemistry and Molecular Biology, School of Medicine, University of Louisville, 319 Abraham Flexner Way, Louisville, KY, 40202, USA.
authors.forename: Yong
authors.initials: Y
authors.lastname: Li
mesh_terms: D000818:Animals; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D009369:Neoplasms / Q000235:genetics*; D015398:Signal Transduction; D018631:ras Proteins / Q000378:metabolism*
chemical_list: C524940:MIRN21 microRNA, human; D035683:MicroRNAs; D016328:NF-kappa B; C487931:mirnlet7 microRNA, human; D018631:ras Proteins