Genetic investigation of FOXE1 polyalanine tract in thyroid diseases: New insight on the role of FOXE1 in thyroid carcinoma

Article type: Research Article

Authors: Kallel, Rihab^{a; b} | Belguith-Maalej, Salima^{a; b} | Akdi, Abdelmounaim^e | Mnif, Mouna^c | Charfeddine, Ilhem^d | Galofré, Pere^{f; g} | Ghorbel, Abdelmonaim^d | ABID, Mohamed^c | Marcos, Ricard^e | Ayadi, Hammadi^b | Velázquez, Antonia^e | Kacem, Hassen Hadj^{a; b; *}

Affiliations: [a] Laboratoire de Microorganismes et Biomolécules, équipe des Procédés de Criblage Moléculaires et Cellulaires, Centre de Biotechnologie de Sfax, Tunisie | [b] Unité Cibles pour le Diagnostic et la Thérapie, Centre de Biotechnologie de Sfax, Tunisie | [c] Service d'Endocrinologie, CHU, Hédi Chaker, Sfax, Tunisie | [d] Service d'Orl, CHU, Hédi Chaker, Sfax, Tunisie | [e] Departament de Genètica i de Microbiologia, Edifici Cn, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain | [f] Servei de Medicina Nuclear, Hospital Universitary Vall d'Hebron, Barcelona, Spain | [g] Present address: Servei de Medicina Nuclear, Hospital Josep Trueta, Girona, Spain

Correspondence: [*] Corresponding author: Dr. Hassen Hadj Kacem, Laboratoire de Microorganismes et Biomolécules, équipe des Procédés de Criblage Moléculaires et Cellulaires, Centre de Biotechnologie de Sfax. Route Sidi Mansour Km 6. BP “1177”, 3018, Sfax, Tunisia. Tel.: +216 74 871 816; Fax: +216 74 875 818. E-mail: [email protected].

Abstract: FOXE1 polyalanine tract (poly-Ala) has been associated with thyroid dysgenesis. Recently, the SNP (rs1867277:-238G>A) within the FOXE1 5'UTR was involved in the genetic susceptibility to thyroid cancer (TC). In the aim to assess the influence of FOXE1 poly-Ala length on the genetic susceptibility to TC and autoimmune thyroid diseases (AITD), a case-control design (including 261 Tunisian AITD, 170 Spanish TC and respectively 171 and 218 matched healthy subjects) was performed. The effect of Ala length and rs1867277 alleles on FOXE1 expression was investigated by mRNA relative real time quantification on 8 papillary thyroid carcinoma (PTC) and 10 Graves' disease (GD) genotyped thyroid biopsies. The fluorescent genotyping of poly-Ala polymorphism revealed nine alleles (from 12 to 22 repetitions). The association of poly-Ala polymorphism with AITD was rejected (Pc>0.05). However, a significant association was found with TC. In addition, the genotypic distributions revealed the predispositional effect of the 16/16 genotype (OR = 2.71; 95%CI: 1.36–5.42; p=0.001) and the protector effect of the 14/14 genotype (OR= 0.46; 95%CI: 0.29–0.72; p=0.003). The quantification studies reveal that FOXE1 transcripts were less abundant in PTC than GD samples. Moreover, FOXEI gene was 4,8 fold less expressed among PTC protected patients compared to homozygous 16/16-A/A. In conclusion, by exploring the poly-Ala polymorphism, we confirmed the involvement of FOXE1 gene in the genetic susceptibility to TC and we reported its down expression among PTC tissues.

Keywords: AITD, thyroid carcinoma, Graves' disease, FOXE1, poly (Ala)

DOI: 10.3233/DMA-2011-0824

Journal: Cancer Biomarkers, vol. 8, no. 1, pp. 43-51, 2011