Activation of PLAG1 and HMGA2 by gene fusions involving the transcriptional regulator gene NFIB.
Genes Chromosomes Cancer
; 59(11): 652-660, 2020 11.
Article
en En
| MEDLINE
| ID: mdl-32654217
ABSTRACT
The pleomorphic adenoma (PA), which is the most common salivary gland neoplasm, is a benign tumor characterized by recurrent chromosome rearrangements involving 8q12 and 12q14-15. We have previously shown that the PLAG1 and HMGA2 oncogenes are the targets of these rearrangements. Here, we have identified previously unrecognized subsets of PAs with ins(9;8)/t(8;9) (n = 5) and ins(9;12)/t(9;12) (n = 8) and breakpoints located in the vicinity of the PLAG1 and HMGA2 loci. RNA-sequencing and reverse transcriptase (RT)-PCR analyses of a case with an ins(9;8) revealed a novel NFIB-PLAG1 fusion in which NFIB exon 4 is linked to PLAG1 exon 3. In contrast to the developmentally regulated PLAG1 gene, NFIB was highly expressed in normal salivary gland, indicating that PLAG1 in this case, as in other variant fusions, is activated by promoter swapping. RT-PCR analysis of three PAs with t(9;12) revealed two tumors with chimeric transcripts consisting of HMGA2 exon 4 linked to NFIB exons 9 or 3 and one case with a fusion linking HMGA2 exon 3 to NFIB exon 9. The NFIB fusion events resulted in potent activation of PLAG1 and HMGA2. Analysis of the chromatin landscape surrounding NFIB revealed several super-enhancers in the 5'- and 3'-parts of the NFIB locus and its flanking sequences. These findings indicate that PLAG1 and HMGA2, similar to MYB in adenoid cystic carcinoma, may be activated by enhancer-hijacking events, in which super-enhancers in NFIB are translocated upstream of PLAG1 or downstream of HMGA2. Our results further emphasize the role of NFIB as a fusion partner to multiple oncogenes in histopathologically different types of salivary gland tumors.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Neoplasias de las Glándulas Salivales
/
Regulación Neoplásica de la Expresión Génica
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Proteínas de Fusión Oncogénica
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Proteína HMGA2
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Proteínas de Unión al ADN
/
Factores de Transcripción NFI
Tipo de estudio:
Prognostic_studies
Límite:
Humans
Idioma:
En
Revista:
Genes Chromosomes Cancer
Asunto de la revista:
BIOLOGIA MOLECULAR
/
NEOPLASIAS
Año:
2020
Tipo del documento:
Article
País de afiliación:
Suecia