Gabriela Anton

Quantitative analysis of the relationship between microRNA‑124a, -34b and -203 gene methylation and cervical oncogenesis

Cervical cancer is a leading cause of mortality in women. Molecular and epidemiological data have unequivocally confirmed that high-risk human papillomaviruses (HPVs) are a major etiological agent of this malignancy, as host epigenetic alterations are induced in response to viral infection. The present study evaluated the methylation status of CpG islands surrounding miR-124a, miR-34b and miR-203 in 29 cervical cancer precursor lesions, 31 cervical tumors and 30 normal control samples, with the aim of identifying potential markers of cervical cancer. Direct quantitative methylation-specific PCR (qMSP) was used to evaluate the degree of methylation in the samples. HPV DNA was detected and genotyped using the Linear Array HPV Genotyping Test. Data were statistically analyzed using the Kruskal-Wallis test. Differences in miRNA hypermethylation between the tumor and control samples were highly significant for all the genes tested (p<0.0001). Significant results were also obtained regarding the hypermethylation of miR-124a and miR-203 in the precursor lesions compared to the control samples. Among the 29 patients with precursor lesions, 68.97% (20/29) presented high risk (hr)-HPV genotypes and 31.03% (9/29) were diagnosed with low risk (lr)-HPV. Significant results (p=0.0266) were obtained for miR-124a (hr-HPV group, mean 41.32; lr-HPV group, mean 6.74), revealing a strong association between the methylation process and the hr-HPV genotype. Borderline results (p=0.058) were obtained for miR-203 (hr-HPV group, mean 44.05; lr-HPV group, mean 3.33). These results confirm the involvement of epigenetic alterations in cervical oncogenesis. The lr-HPV precursor lesions had a methylation percent pattern similar to that of the normal samples, while the results for the hr-HPV precursor lesions and tumors indicate a possible involvement of the hr-HPV genotype in the miRNA methylation process.

Methylenetetrahydrofolate reductase (MTHFR) polymorphisms and promoter methylation in cervical oncogenic lesions and cancer.

The aim of this study was to investigate the role of methylenetetrahydrofolate reductase (MTHFR) polymorphisms and MTHFR methylation pattern in cervical lesions development among women from Romania, a country with high prevalence of human papillomavirus (HPV) cervical infections. To achieve this goal, blood samples and cervical cytology specimens (n = 77)/tumour tissue specimens (n = 23) were investigated. As control, blood and negative cytological smears (n = 50) were used. A statistically significant association was found between T allele of C677T polymorphism and cervical lesions, heterozygote women presenting a threefold increased risk (normal/cervical lesions and tumours: wild homozygote 34/41 (0.68/0.41), heterozygote 14/51 (0.28/0.51), mutant homozygote 2/8 (0.04/0.08); OR = 3.081, P = 0.0035). Using χ square test for the control group, the HPV‐negative and HPV‐positive patients with cervix lesions, a significant correlation between viral infection and T allele of C677T polymorphism (P = 0.0287) was found. The MTHFR promoter was methylated in all HGSIL and tumour samples, significant differences being noted between HPV‐positive samples, control group and cases of cervical dysplastic lesions without HPV DNA (P < 0. 0001) and between samples from patients with high‐risk (hr)HPV versus low‐risk (lr)HPV (P = 0.0026). No correlations between polymorphisms and methylation were observed. In Romania, individuals carrying T allele are susceptible for cervical lesions. MTHFR promoter methylation is associated with cervical severity lesions and with hrHPV.

Bacteriological agents which play a role in the development of infertility.

This study was carried out to determine the prevalence of the bacterial agents Chlamydia trachomatis (C. trachomatis), Neisseria gonorrhoeae (N. gonorrhoeae), Mycoplasma hominis (M. hominis) and Ureaplasma urealyticum (U. urealyticum) and the conditions which may play a role in the development of female infertility, in the county of Iaşi in North-Eastern Romania. Cervical and blood samples were collected from 176 infertile women and 45 pregnant women in the third trimester. Classical methods and real time PCR were applied to each cervical sample to detect the presence of these sexually transmitted microorganisms; the ELISA method was applied to blood samples to detect C. trachomatis antibodies (IgA, IgM and IgG). The proportion of C. trachomatis IgG was significantly higher in the infertile group (23.8%) than in the pregnant group (4.4%), p < 0.05. For C. trachomatis antigen (Ag) and N. gonorrhoeae Ag no differences were observed between the two groups. The prevalence of mycoplasma genital infections was higher in the pregnant group (U. urealyticum - 53.3% and M. hominis - 20%) than in the infertile group (U. urealyticum - 39.7% and M. hominis - 7.3%). Higher rate of co-infection with C. trachomatis and mycoplasma were observed among the infertile women (25.7%) than among the pregnant women (7.7%). This combination could be involved in the appearance of pelvic inflammatory disease (PID) and its sequela, including infertility. C. trachomatis IgG determination still remains the gold standard for the diagnosis of PID and should be used as a screening test for the prediction of tubal damage in infertile women. In view of the large number of cases involving the co-existence of genital infections with C. trachomatis, M. hominis and U. urealyticum, it is clearly necessary to perform screening for all three microorganisms among all women of reproductive age but especially those who are infertile.

Methylation pattern of methylene tetrahydrofolate reductase and small nuclear ribonucleoprotein polypeptide N promoters in oligoasthenospermia: a case-control study.

Alterations in DNA methylation patterns in several genes may lead to abnormal male sexual development and infertility. This study investigated the promoter methylation status of MTHFR and SNRPN in infertile men from Romania by quantitative methylation-specific PCR in order to investigate possible correlations with sperm abnormalities. The study groups included patients (n=27) with a median age of 31 years (range 26-41 years) as well as controls (n=11) with a median age of 30 years (range 24-37 years) recruited from couples seeking advice for infertility. DNA was isolated from sperm samples and promoter methylation was assessed using direct. Significant trends were detected for both genes that indicate a tendency towards promoter hypermethylation in spermatozoa with low motility (MTHFR P=0.0032, r=0.23; SNRPN P=0.0003, r=0.32) and poor morphology (MTHFR P=0.0012, r=0.27; SNRPN P=0.0003, r=0.33) but no trend was found in cases of low sperm count (MTHFR r=0.007; SNRPN r=0.06). The data indicate that the methylation patterns of the promoters of MTHFR and SNRPN are associated with changes in sperm motility and morphology, which could lead to male infertility. A large number of studies are now focused on the causes of male infertility. Among these are epigenetic modifications, which are important contributors to reproductive pathology in the male by providing dynamic changes of the phenotype according to the environmental and metabolic factors. The most known epigenetic modification is DNA methylation and alterations in this pattern in several genes could induce male infertility. The present study aims to investigate the promoter methylation status of the genes for methylene tetrahydrofolate reductase (MTHFR) and small nuclear ribonucleoprotein polypeptide N (SNRPN) in infertile males from Romania, in order to establish a correlation with sperm parameters. MTHFR is an enzyme involved in the folate pathway and in de novo nucleotide biosynthesis but also a good example for gene-environment interaction in phenotype development. SNRPN is involved in both somatic cell expression and inheritance of the imprint and the methylation pattern of its gene seems to correlate not only with imprinted disorders but also with infertility. Our study includes patients (n=27, median age 31 years, range 26-41 years) recruited from men seeking advice for couple infertility and control group (n=11, median age 30.5 years, range 24-37 years). The data we obtained indicated significant correlations between hypermethylation of the investigated genes and sperm motility and morphology. No significant correlation between DNA methylation and sperm number was found. Our data suggest that methylation pattern of MTHFR and SNRPN is linked with sperm anomalies of motility and morphology and therefore male infertility.

Detection of human papillomavirus gene sequences in cell lines derived from laryngeal tumors

The role of Human Papillomaviruses (HPV) in laryngeal carcinomas has been studied with conflicting results. To evaluate the etiologic relationship between HPV infection and epithelial malignancy of the larynx we studied five laryngeal carcinoma cell lines obtained from patients undergoing surgery for laryngeal tumors. The paraffin embedded biopsy samples of the original tumor and different passages of the new established cell lines were investigated by PCR with consensus primers specific for HPV DNA. The findings indicate that HPV infection is associated with some larynx carcinomas. The positive association has been enhanced when a method of enrichment of epithelial cells from fresh tumor samples was used. All tumor cells enriched smears were positive for HPV DNA not only by PCR but also by in situ hybridization (ISH). Investigated by PCR, different passages of larynx tumor cell lines maintained expression of HPV DNA. At subsequent passages ISH gives constantly no signals suggesting a minimal amount of viral harbored sequences. In one cell line propagated more than 60 population doublings, the chromosomal frequency distribution shifted from modal number 46 at the 5th passage to 63 at the 60th passage. The mechanisms by which persistent HPV infection maintains continuous cell proliferation were discussed.

Type-specific human papillomavirus detection in cervical smears in Romania.

Anton G, Peltecu G, Socolov D, Cornitescu F, Bleotu C, Sgarbura Z, Teleman S, Iliescu D, Botezatu A, Goia CD, Huica I, Anton A‐C. Type‐specific human papillomavirus detection in cervical smears in Romania. APMIS 2010.

miR-29a associates with viro-immunological markers of HIV infection in treatment experienced patients.

MicroRNAs (miRNAs) are small, non‐coding RNA species essential for the post‐translational regulation of gene expression. Several miRNA have been proposed to contribute to Human immunodeficiency virus‐1 (HIV‐1) infection establishment, progression and latency. Among them, miR‐29a seems to be of particular interest. The aim of this study was to investigate the association between miR‐29a expression and immunologic and virologic markers of HIV infection progression in long‐term antiretroviral‐treated individuals. In a homogenous group of 165 young adults, with chronic HIV infection, parenterally acquired during childhood, the expression level of miR‐29a was found to be inversely correlated with HIV viral load and the degree of immunosuppression, expressed by both CD4 cell count and the CD4/CD8 ratio. There was a significant difference in miR‐29a expression according to the patients response to treatment, with the lowest levels expressed by patients with treatment failure, defined as detectable viremia and CD4 < 350 cells/mm3. No significant correlation was found between miRNA level and the nadir CD4 count or zenith HIV viral load. This study establishes the association between miR‐29a expression and markers of HIV infection in long‐term survivors, treatment‐experienced patients, suggesting its potential use as an indicator for the on‐treatment disease evolution. J. Med. Virol. 88:2132–2137, 2016.

Immunoassay and molecular methods to investigate DNA methylation changes in peripheral blood mononuclear cells in HIV infected patients on cART

ABSTRACT This study aimed to investigate the influence of antiretroviral therapy on methylation markers, in a group of HIV infected, heavily treated patients. Immune and molecular methods were used to investigate potential changes in methylation profile in DNA isolated from peripheral blood mononuclear cells collected from antiretroviral-experienced HIV infected patients and healthy controls. The percentage of 5-methylcytosine was inversely correlated with proviral DNA and active replication while DNMT1 (p = 0.01) and DNMT3A (p = 0.004) independently correlated with active viral replication. DNMT3A expression increased with total treatment duration (p = 0.03), number of antiretroviral drugs ever used (p = 0.003), and cumulative exposure to protease inhibitors (p = 0.02) even in currently HIV undetectable patients.

LINC01101 and LINC00277 expression levels as novel factors in HPV‐induced cervical neoplasia

Recently long non‐coding RNAs were identified as new factors involved in gene expression regulation. To gain insight into expression pattern of these factors related to E7 HPV18 oncogene, this study uses HeLa cell culture transfected with E7‐siRNA. Gene expression profile was investigated using microarray analysis. After analysing the microarray results, we identified 15,387 RNA species differentially expressed in E7‐siRNA‐transfected cells compared with controls (fold change >2). The expression profiles of lncRNA species highlighted 731 lncRNAs and 203 lincRNAs. We selected two lincRNAs (LINC01101 and LINC00277) and we evaluated the expression profile in HPV‐induced neoplasia. Both lincRNAs investigated display a significantly reduced pattern of expression in cervical lesions and cancer, associated with clinical parameters. A connection between HPV presence and lincRNAs was noted. hrHPV‐positive samples exhibit significantly reduced LINC01101 and LINC00277 expression level (P < 0.05). These results provide new insights into involvement of lncRNA in HPV‐induced cervical cancer, enriching our understanding of their potential role in this pathology.

The development of larger cells that spontaneously escape senescence - a step during the immortalization of a human cancer cell line

There are few information concerning the changes associated with the transition interval when slow growing, primary explanted human cancer cells are displaced by new selected faster growing cells and became an immortal cell line. In a previous paper (J. Cell. Mol. Med., 5: 49–59, 2001) we described the TV cell line derived from a laryngeal tumor which harbors human papillomavirus (HPV) gene sequences throughout more than sixty in vitro passages. In this paper we analyze the modifications observed during the crisis interval when significant amount of cells senesce but occasional cells acquire some mutations that make them immortal. Confocal microscopy analysis revealed the heterogeneity of the cells in terms of their size and nucleus/cell ratio. Proliferation capacity was assessed by flow cytometry analyzing DNA content and expression of transferrin receptor (CD71). We discussed the possibility that HPV genome sequences alleviate a proliferation block during the crisis growth arrest of human larynx carcinoma cell line and the possibility that the cells monitor their size and growth by measuring the levels of some protein whose synthesis is coupled to cell development.