Publications by authors named "Amel Ben Ammar El Gaaied"

15 Publications

  • Page 1 of 1

Genetic variation of 17 X-chromosome STR loci in Tunisian population of Nabeul.

Int J Legal Med 2019 Jan 22;133(1):85-88. Epub 2018 Mar 22.

Laboratory of Genetics, Immunology, and Human Pathologies, Faculty of Science of Tunis, University Tunis El Manar, Tunis, Tunisia.

In the present study, the genetic variations of 17 X-STR markers (DXS8378, DXS9898, DXS7133, GATA31E08, GATA172D05, DXS6801, DXS7423, DXS6809, DXS6799, DXS7132, DXS9902, DXS6800, DXS6789, DXS10075, DXS10079, DXS6807, and DXS6803) were analyzed in 139 unrelated individuals in Nabeul, aiming to perform an X-STR database for anthropological and forensic purposes. Our results indicate that DXS6809 was the most polymorphic locus, whereas DXS6807 was the least informative marker. In addition, the obtained values for the statistical parameters of forensic interest, i.e., the power of discrimination in males (PD) and females (PD), as well as the mean exclusion chance in duos (MEC) and trios (MEC) have demonstrated that this panel of 17 X-STRs is highly informative and useful for forensic application and anthropological research. Additionally, pairwise genetic distances based on F were calculated between Nabeul population and other populations extracted from the literature. Genetic distances were represented in a non-metric MDS plot and clustering of populations according to their geographic locations and their historical relationship was detected.
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http://dx.doi.org/10.1007/s00414-018-1827-3DOI Listing
January 2019

Clinical significance of T-bet, GATA-3, and Bcl-6 transcription factor expression in bladder carcinoma.

J Transl Med 2016 05 30;14(1):144. Epub 2016 May 30.

Laboratoire d'Immunologie et Immunothérapie des Cancers (LIIC), EPHE, PSL Research University, 75014, Paris, France.

Background: The aim of this study was to investigate the clinical significance of three immune cell-related transcription factors, T-bet, GATA-3 and Bcl-6 in bladder cancer in Tunisian patients.

Methods: Expression of T-bet, GATA-3 and Bcl-6 genes was assessed using RT-qPCR in 65 bladder cancers from patients: 32 being diagnosed as low- and medium-grade, 31 as high-grade, 25 as muscle invasive stage and 39 as non-muscle invasive stage. Gene expression was statistically correlated according to the grade, the stage, tobacco consumption, the BCG response and disease severity.

Results: T-bet levels in patients with high-grade bladder cancer were significantly elevated compared to patients with low- or medium-grade bladder cancer (p = 0.005). In invasive carcinoma (T2-T4), the T-bet levels were significantly higher than in superficial non-invasive bladder tumors (Tis, Ta, and T1) (p = 0.02). However, T-bet is predictive of the response to BCG. Its expression is high in good responders to BCG (p = 0.02). In contrast, the expression of GATA-3 and Bcl-6 in non-invasive carcinoma (p = 0.008 and p = 0.0003) and in patients with low- and medium-grade cancers (p = 0.001 and p < 0.0001) is significantly higher than in invasive bladder tumors and in patients with high-grade bladder carcinoma, respectively. In addition, heavy smokers, whose tumors express low levels of GATA-3 and Bcl-6, are poor responders to BCG (p = 0.01 and p = 0.03). Finally, better patient survival correlated with GATA-3 (p = 0.04) and Bcl-6 (p = 0.04) but not T-bet expression.

Conclusions: Our results suggest that T-bet expression in bladder tumors could be a positive prognostic indicator of BCG therapy, even if high levels are found in high-grade and stage of the disease. However, GATA-3 and Bcl-6 expression could be considered as predictive factors for good patient survival.
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http://dx.doi.org/10.1186/s12967-016-0891-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4885121PMC
May 2016

Akt activation correlates with the tumor aggressiveness in Tunisian patients with bladder cancer.

Tumour Biol 2016 Jun 23;37(6):7873-9. Epub 2015 Dec 23.

EPHE, Laboratoire d'Immunologie et Immunothérapie des Cancers, Paris, F-75014, France.

Various studies in western countries found Akt amplification to be a frequent event in human cancers, including bladder, but the correlation with clinicopathological features is controversial. Such studies have not been reported in African populations, including Tunisians. The purpose of this study was to assess expression of the phosphorylated/activated forms of Akt in tumors from Tunisian patients with bladder cancer and to correlate its expression with pathological and clinical parameters of the disease. The study included 72 patients of whom 34 were diagnosed as low- to medium-grade and 35 as high-grade; 30 were muscle stage and 39 non-muscle stage. Primary tumors from these patients, normal adjacent tissues, or bladder cancer cell-lines were analyzed for Ser473 phosphorylated Akt expression by Western blot. Seventy-two percent of primary tumors from patients with bladder cancer had increased levels of p-Akt. The p-Akt levels in patients with high-grade bladder cancer were significantly elevated compared to patients with low- or medium-grade bladder cancer. In invasive carcinoma, the p-Akt level was significantly higher than in superficial non-invasive bladder tumors. Concerning the influence of tobacco on Akt activation, no significant differences of p-Akt expression were found between non-smoker and smoker patients. Altogether, our results suggest that Akt activation can provide useful prognostic information and that tobacco represents a serious risk factor for recurrence in a cohort of Tunisian patients.
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http://dx.doi.org/10.1007/s13277-015-4678-2DOI Listing
June 2016

An investigation of the genetic diversity of the Kerkennah islands and Mahdia (Tunisia) using biparental markers.

Ann Hum Biol 2014 Jan-Feb;41(1):53-60. Epub 2013 Aug 21.

Laboratory of Molecular Genetics, Immunology and Human Pathology at the Faculty of Sciences of Tunis, University El Manar , 2092 Tunis , Tunisia and.

Background: Kerkennah is one of the main inhabited islands of Tunisia. The origin of the population of Kerkennah has not been established and no well-defined ethnic groups have been identified nor are genetic studies available. Mahdia, a Tunisian coastal city, has a long history dating back to ancient times.

Aim: To discover the genetic diversity of the two studied populations and analyse their relationships with other Mediterranean populations.

Subject And Methods: Seven human-specific Alu insertion polymorphisms were typed in 99 individuals born in Kerkennah and Mahdia.

Results: A neighbour-joining tree and MDS multidimensional scaling analysis showed that these Tunisian populations are scattered amongst North African and Europeans populations, indicating their high genetic diversity and mosaic aspect. The important finding of this study was the proximity of Kerkennah to Moroccans. Hence, the actual gene pool of this insular population may descend from the ancestral population known to be of Moroccan origin. Concerning Mahdia, its closeness to Eurasian populations and some Tunisian groups reflected a high Eurasian genetic component for North African populations and confirmed their heterogeneity.

Conclusion: The strategic location of the two studied populations and their fortifications have allowed them to play a leading role in the Mediterranean basin.
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http://dx.doi.org/10.3109/03014460.2013.824025DOI Listing
July 2014

Assessment of Aurora A kinase expression in breast cancer: a tool for early diagnosis?

Dis Markers 2013 ;34(2):63-9

Laboratory of Genetics, Immunology and Human Pathology, Department of Biology, Faculty of Sciences of Tunis, Tunis, Tunisia.

Aurora A kinase is overexpressed in many cancers but the status of this protein in the breast cancer often varies. We investigate the expression and localization of Aurora A protein in relation with tumor emergence and progression in breast cancer. Aurora A kinase status was evaluated in 107 patients using immunohistochemistry. The experimental findings showed that high expression of the Aurora A protein was correlated with elevated nuclear grade, low expression of progesterone receptor and positive nodal status. The experimental results showed also that the localization of this kinase shifts from cytoplasm in non malignant adjacent tissue to both cytoplasmic and nuclear compartments in tumoral tissue, suggesting an oncogenic role of the nuclear accumulation. We have, furthermore, detected the overexpression of this protein in non malignant adjacent tissue. The expression of the Aurora A kinase in non malignant tissue may represent an earlier diagnosis tool for breast cancer.
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http://dx.doi.org/10.3233/DMA-120947DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3810251PMC
August 2013

Association analysis of LCE3C-LCE3B deletion in Tunisian psoriatic population.

Arch Dermatol Res 2012 Nov 29;304(9):733-8. Epub 2012 Aug 29.

Laboratory of Genetics, Immunology and Human Pathologies, Department of Biology, Tunis, Tunisia.

An association between a common deletion comprising the late cornified envelope LCE3B and LCE3C genes (LCE3C_LCE3B-del) and psoriasis has been reported in Caucasian and Asian populations. To investigate whether this deletion plays a role in the genetic of psoriasis in Tunisian population, we determined the LCE3C_LCE3B-del genotype in 180 Ps patients and 208 healthy controls from different regions of Tunisia. The LCE3B and LCE3C gene variant was determined in the patients through PCR amplification and the SPSS software package. The frequency of the LCE3C_LCE3B-del was similar between patients and healthy controls. Subanalyses by family history revealed that the frequency of LCE3C_LCE3B-del was significantly higher in patients with a positive family history than in control individuals, as well as in individuals with a positive family history versus those without in the case cohort. However, no significant difference was observed between psoriatic patients with no family history and controls. We also evaluated the relationship between LCE3C_LCE3B-del and PSORS1. No significant epistatic effect was observed suggesting that there was no significant epistasis of the two loci in the Tunisian population. Our findings indicate that the LCE3C_LCE3B-del might play a role in familial psoriasis in the Tunisian population.
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http://dx.doi.org/10.1007/s00403-012-1279-4DOI Listing
November 2012

[Immunogenetics of psoriasis: update].

Tunis Med 2012 Jul;90(7):512-7

Laboratoire de genetique, Immunologie et pathologie humaine, Faculte des sciences de Tunis.

Background: Psoriasis is a chronic inflammatory skin disease often benign, affecting 2-3% of the total world population. Psoriasis is a multifactorial disease.

Aim: To present recent advances in the immunologic mechanisms and susceptibility genes involved in the pathogenesis of psoriasis.

Methods: We presented a literature review of recent genetic and immunological basis of psoriasis to better understand the pathomecanisms of this disease and discuss the contribution of the Tunisian work in this area.

Results: Recent works focalized mainly in immunology and genetics. Current progresses in molecular biology have allowed to better characterize the immunogenetic abnormalities in psoriasis.

Conclusion: Psoriasis is a multifactorial disease model in which environmental factors (psychological, climate, traumatic, infectious, and viral) seem to be triggering factors when associated with a particular immunogenetics predisposition.
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July 2012

Population history of the Red Sea--genetic exchanges between the Arabian Peninsula and East Africa signaled in the mitochondrial DNA HV1 haplogroup.

Am J Phys Anthropol 2011 Aug 9;145(4):592-8. Epub 2011 Jun 9.

Department of Anthropology and Human Genetics, Faculty of Science, Charles University, Prague, Czech Republic.

Archaeological studies have revealed cultural connections between the two sides of the Red Sea dating to prehistory. The issue has still not been properly addressed, however, by archaeogenetics. We focus our attention here on the mitochondrial haplogroup HV1 that is present in both the Arabian Peninsula and East Africa. The internal variation of 38 complete mitochondrial DNA sequences (20 of them presented here for the first time) affiliated into this haplogroup testify to its emergence during the late glacial maximum, most probably in the Near East, with subsequent dispersion via population expansions when climatic conditions improved. Detailed phylogeography of HV1 sequences shows that more recent demographic upheavals likely contributed to their spread from West Arabia to East Africa, a finding concordant with archaeological records suggesting intensive maritime trade in the Red Sea from the sixth millennium BC onwards. Closer genetic exchanges are apparent between the Horn of Africa and Yemen, while Egyptian HV1 haplotypes seem to be more similar to the Near Eastern ones.
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http://dx.doi.org/10.1002/ajpa.21522DOI Listing
August 2011

Internal diversification of mitochondrial haplogroup R0a reveals post-last glacial maximum demographic expansions in South Arabia.

Mol Biol Evol 2011 Jan 19;28(1):71-8. Epub 2010 Jul 19.

Archaeogenetics Laboratory, Institute of Archaeology of the Academy of Sciences of the Czech Republic, Prague, The Czech Republic.

Widespread interest in the first successful Out of Africa dispersal of modern humans ∼60-80 thousand years ago via a southern migration route has overshadowed the study of later periods of South Arabian prehistory. In this work, we show that the post-Last Glacial Maximum period of the past 20,000 years, during which climatic conditions were becoming more hospitable, has been a significant time in the formation of the extant genetic composition and population structure of this region. This conclusion is supported by the internal diversification displayed in the highly resolved phylogenetic tree of 89 whole mitochondrial genomes (71 being newly presented here) for haplogroup R0a-the most frequent and widespread haplogroup in Arabia. Additionally, two geographically specific clades (R0a1a1a and R0a2f1) have been identified in non-Arabic speaking peoples such as the Soqotri and Mahri living in the southern part of the Arabian Peninsula where a past refugium was identified by independent archaeological studies. Estimates of time to the most recent common ancestor of these lineages match the earliest archaeological evidence for seafaring activity in the peninsula in the sixth millennium BC.
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http://dx.doi.org/10.1093/molbev/msq178DOI Listing
January 2011

[Penetrance of BRCA1 gene mutation and DNA mitochondrial in Tunisian breast cancer occurrence].

Tunis Med 2009 Aug;87(8):494-8

Laboratory of Genetics, Immunology and Human Pathology, Faculty of Sciences of Tunis, University El Manar I.

Aim: The aim of this study is to evaluate the implication of BRCA1 gene and the mitochondrial micro satellite (situated between 303 and 315 positions) mutations in the occurrence of breast cancer in Tunisia.

Methods: Nine Tunisian patients with hereditary breast cancer have been analyzed. For each patient, total genomic DNA was extracted and used as a template for the amplification of 24 exons of the BRCA1 gene and an hyper variable mitochondrial region. The obtained products were purified and automatically sequenced.

Results: The results revealed five types of mutations for the micro satellite situated between the 303 and 315 positions and two deleterious BRCA1 mutations for two unrelated patients which present the same mitochondrial mutation (315.insC) suggesting his implication in the modulation of the BRCA1 deleterious mutations penetrance.
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August 2009

Data from complete mtDNA sequencing of Tunisian centenarians: testing haplogroup association and the "golden mean" to longevity.

Mech Ageing Dev 2009 Apr 24;130(4):222-6. Epub 2008 Dec 24.

IPATIMUP (Instituto de Patologia e Imunologia Molecular da Universidade do Porto), Porto, Portugal.

Since the mitochondrial theory of ageing was proposed, mitochondrial DNA (mtDNA) diversity has been largely studied in old people, however complete genomes are still rare, being limited to Japanese and UK/US samples. In this work, we evaluated possible longevity associated polymorphisms/haplogroups in an African population, from Tunisia, by performing complete mtDNA sequencing. This population has a mixed Eurasian/sub-Saharan mtDNA gene pool, which could potentially facilitate the evaluation of association for sub-Saharan lineages. Sub-Saharan haplogroups were shown to be significantly less represented in centenarians (9.5%) than in controls (54.5%), but it is not possible to rule out an influence of population structure, which is high in these populations. No recurrent polymorphism were more frequent in centenarians than in controls, and although the Tunisian centenarians presented less synonymous and replacement polymorphisms than controls, this difference was not statistically significant. So far, it does not seem that centenarians have significantly less mildly deleterious substitutions, not only in Tunisia but also in Japanese and UK/US samples, as tested here, not favouring a "golden mean" to longevity.
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http://dx.doi.org/10.1016/j.mad.2008.12.001DOI Listing
April 2009

Post-last glacial maximum expansion from Iberia to North Africa revealed by fine characterization of mtDNA H haplogroup in Tunisia.

Am J Phys Anthropol 2009 Jun;139(2):253-60

Laboratory of Genetics Immunology and Human Pathology, Faculty of Sciences of Tunis, Tunisia.

The first large-scale fine characterization of Tunisian H lineages clarifies that the post-Last glacial maximum expansion originating in Iberia not only led to the resettlement of Europe but also of North Africa. We found that 46% of 81 Tunisian H lineages subscreened for 1,580 bp in mtDNA coding region were affiliated with H1 and H3 subhaplogroups, which are known to have originated in Iberia. Although no signs of local expansion were detected, which would allow a clear dating of their introduction, the younger and less diverse Tunisian H1 and H3 lineages indicate Iberia as the radiating centre. Major contributions from historical migrations to this Iberian genetic imprint in Tunisia were ruled out by the mtDNA gene pool similarity between Berber/Arab/cosmopolitan samples and some "Andalusian" communities, settled by the descendents of the "Moors" who once lived in Iberia for 10 centuries (between 8th and 17th centuries), before being expelled to Tunisia.
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http://dx.doi.org/10.1002/ajpa.20979DOI Listing
June 2009

The role of CYP2D6*4 variant in bladder cancer susceptibility in Tunisian patients.

Bull Cancer 2008 Feb;95(2):E1-4

Laboratoire de génétique, immunologie et pathologies humaines, Faculté des Sciences, El Mannar I, 2092 Tunis, Tunisia.

CYP2D6 enzyme is implicated in the metabolism of drugs and nicotine. Genetic variability within CYP2D6, results in different CYP2D6 phenotypes. Inheritance of polymorphic CYP2D6 metabolizing enzyme is likely to be an important determinant of inter-individual variations in susceptibility to cancer. In this work, we have conducted a case control study in order to assess the role of CYP2D6*4 variant in bladder cancer development in a Tunisian cohort. A total of 80 patients with TCC of bladder cancer and 109 healthy controls were included in the present study. The frequency of CYP2D6*4 allele, characterized by loss of BstNI site, was observed in 8.25% of healthy volunteers and in 10.62% of patients. The CYP2D6*4/CYP2D6*4 genotype was observed in only 2.75% of controls and was absent in cases. In all group of patients, the CYP2D6*4 allele did not appear to influence bladder cancer susceptibility (p > 0.05). A similar result was obtained when we stratified cases group according to tobacco status. Conversely, patients carrying the BstNI site at the homozygous state, mostly combined as homozygous wild genotype, could be at more risk of bladder cancer invasiveness than those having the heterozygous genotype.
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http://dx.doi.org/10.1684/bdc.2008.0583DOI Listing
February 2008

Identification of the CCR5-Delta32 HIV resistance allele and new mutations of the CCR5 gene in different Tunisian populations.

Hum Immunol 2007 Dec 30;68(12):993-1000. Epub 2007 Oct 30.

Laboratoire de Génétique, Immunologie et Pathologies Humaines, Faculté des Sciences de Tunis, Université Tunis El Manar, Tunis, Tunisie.

Polymorphisms in some chemokine receptor genes are associated with susceptibility to and progression of human immunodeficiency virus-1 (HIV-1) infection. Most mutations detected in the CC-chemokine receptor 5 (CCR5) gene are specific to different populations. In this study, we focused on polymorphisms of the CCR5 coding region in three healthy populations from Tunisia, corresponding to a cosmopolitan population from Tunis, and two isolated Berber populations. In addition to the CCR5-Delta32 deletion, eleven single nucleotide polymorphisms were detected. Some of these point mutations were associated with the same genotype and even the same haplotype. The (L55Q-C101X), I124, V131F, T143N, A159V, I237, T239A and G301R alleles have not been described previously, whereas the CCR5-Delta32, L55Q, A335V and Y339F variants have already been reported in the literature. The distribution and frequency of these variants were different among the three groups studied, a result in agreement with the mosaic genetic structure of the Tunisian population. To determine whether these alleles affect HIV-1 transmission, we compared allele frequencies between healthy and HIV-1 infected individuals from Tunis. The frequency of the CCR5-Delta32 variant was significantly different between the two groups, leading us to conclude that this mutation might confer protection against HIV infection in Tunisian populations.
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http://dx.doi.org/10.1016/j.humimm.2007.10.003DOI Listing
December 2007

Female gene pools of Berber and Arab neighboring communities in central Tunisia: microstructure of mtDNA variation in North Africa.

Hum Biol 2005 Feb;77(1):61-70

Laboratory of Molecular Genetics, Immunology, and Biotechnology, Faculty of Sciences of Tunis, University of Tunis, El Manar II 1060, Tunisia.

North African populations are considered genetically closer to Eurasians than to sub-Saharans. However, they display a considerably high mtDNA heterogeneity among them, namely in the frequencies of the U6, East African, and sub-Saharan haplogroups. In this study, we describe and compare the female gene pools of two neighboring Tunisian populations, Kesra (Berber) and Zriba (non-Berber), which have contrasting historical backgrounds. Both populations presented lower diversity values than those observed for other North African populations, and they were the only populations not showing significant negative Fu's F(S) values. Kesra displayed a much higher proportion of typical sub-Saharan haplotypes (49%, including 4.2% of M1 haplogroup) than Zriba (8%). With respect to U6 sequences, frequencies were low (2% in Kesra and 8% in Zriba), and all belonged to the subhaplogroup U6a. An analysis of these data in the context of North Africa reveals that the emerging picture is complex, because Zriba would match the profile of a Berber Moroccan population, whereas Kesra, which shows twice the frequency of sub-Saharan lineages normally observed in northern coastal populations, would match a western Saharan population except for the low U6 frequency. The North African patchy mtDNA landscape has no parallel in other regions of the world and increasing the number of sampled populations has not been accompanied by any substantial increase in our understanding of its phylogeography. Available data up to now rely on sampling small, scattered populations, although they are carefully characterized in terms of their ethnic, linguistic, and historical backgrounds. It is therefore doubtful that this picture truly represents the complex historical demography of the region rather than being just the result of the type of samplings performed so far.
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http://dx.doi.org/10.1353/hub.2005.0028DOI Listing
February 2005