title: Gene silencing of Nox4 by CpG island methylation during hepatocarcinogenesis in rats.
abstract: The association between the downregulation of genes and DNA methylation in their CpG islands has been extensively studied as a mechanism that favors carcinogenesis. The objective of this study was to analyze the methylation of a set of genes selected based on their microarray expression profiles during the process of hepatocarcinogenesis. Rats were euthanized at: 24 h, 7, 11, 16 and 30 days and 5, 9, 12 and 18 months post-treatment. We evaluated the methylation status in the CpG islands of four deregulated genes (Casp3, Cldn1, Pex11a and Nox4) using methylation-sensitive high-resolution melting technology for the samples obtained from different stages of hepatocarcinogenesis. We did not observe methylation in Casp3, Cldn1 or Pex11a. However, Nox4 exhibited altered methylation patterns, reaching a maximum of 10%, even during the early stages of hepatocarcinogenesis. We observed downregulation of mRNA and protein of Nox4 (97.5% and 40%, respectively) after the first carcinogenic stimulus relative to the untreated samples. Our results suggest that Nox4 downregulation is associated with DNA methylation of the CpG island in its promoter. We propose that methylation is a mechanism that can silence the expression of Nox4, which could contribute to the acquisition of neoplastic characteristics during hepatocarcinogenesis in rats.
authors.affiliation: Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Av. IPN No. 2508 Col. San Pedro Zacatenco, CDMX CP 07360, México.
authors.forename: Guadalupe S
authors.initials: GS
authors.lastname: López-Álvarez
authors.affiliation: Aarhus Institute of Advanced Studies and Department of Biomedicine, Bartholins Allé 6 Building, 1242, 8000 Aarhus C, Denmark.
authors.forename: Tomasz K
authors.initials: TK
authors.lastname: Wojdacz
authors.affiliation: Instituto Nacional de Cancerología (INCan), Subdirección de Investigación Básica, San Fernando No. 22, Tlalpan, CDMX CP 14080, México.
authors.forename: Claudia M
authors.initials: CM
authors.lastname: García-Cuellar
authors.affiliation: Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Av. IPN No. 2508 Col. San Pedro Zacatenco, CDMX CP 07360, México.
authors.forename: Hugo C
authors.initials: HC
authors.lastname: Monroy-Ramírez
authors.affiliation: Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Av. IPN No. 2508 Col. San Pedro Zacatenco, CDMX CP 07360, México.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Rodríguez-Segura
authors.affiliation: Departamento de Bioquímica, Escuela Nacional de Ciencias Biológicas-IPN, Carpio y Plan de Ayala S/N, Col. Casco de Santo Tomas, CDMX CP 11340, México.
authors.forename: Ruth A
authors.initials: RA
authors.lastname: Pacheco-Rivera
authors.affiliation: Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Av. IPN No. 2508 Col. San Pedro Zacatenco, CDMX CP 07360, México.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Valencia-Antúnez
authors.affiliation: Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Av. IPN No. 2508 Col. San Pedro Zacatenco, CDMX CP 07360, México.
authors.forename: Nancy
authors.initials: N
authors.lastname: Cervantes-Anaya
authors.affiliation: Instituto Nacional de Cancerología (INCan), Subdirección de Investigación Básica, San Fernando No. 22, Tlalpan, CDMX CP 14080, México.
authors.forename: Ernesto
authors.initials: E
authors.lastname: Soto-Reyes
authors.affiliation: CONACYT, Facultad de Medicina y Cirugía, Universidad Autónoma "Benito Juárez" de Oaxaca, Ex-Hacienda de Aguilera S/N Carretera a San Felipe del Agua, Oaxaca, Oax., CP 68020, México.
authors.forename: Verónica R
authors.initials: VR
authors.lastname: Vásquez-Garzón
authors.affiliation: Instituto Nacional de Cancerología (INCan), Subdirección de Investigación Básica, San Fernando No. 22, Tlalpan, CDMX CP 14080, México yesennia.sanchez@salud.gob.mx svilla@cell.cinvestav.mx.
authors.forename: Yesennia
authors.initials: Y
authors.lastname: Sánchez-Pérez
authors.affiliation: Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Av. IPN No. 2508 Col. San Pedro Zacatenco, CDMX CP 07360, México yesennia.sanchez@salud.gob.mx svilla@cell.cinvestav.mx.
authors.forename: Saúl
authors.initials: S
authors.lastname: Villa-Treviño
keywords: Casp3; Chemical hepatocarcinogenesis; Cldn1; Downregulation; Nox4, DNA methylation; Pex11a