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Iancu I.V.,Romanian Academy Stefan S Nicolau Virology Institute
Roumanian archives of microbiology and immunology | Year: 2010

Human papillomaviruses (HPV) are considered the etiological agents of cervical cancer, especially high-risk genotypes. TGF-beta (transforming growth factor-beta) is well known for its anti-proliferative effects but the neoplastic cells often lose their sensitivity to TGF-beta. A characteristic alteration associated with malignant progression is the loss of responsiveness to TGF-beta1-induced cell growth inhibition. The aim of the present study was to establish the possible role of some members of TGF-beta signalling pathway during cervical cancer development and the possible relationship with HPV infection. In order to establish TGF-beta gene expression levels in cervical oncogenesis, TGF-beta1, TGF-beta1 receptors and Smad2 were investigated in precancerous and cervical cancer samples (Quantitative Real-Time PCR). The study revealed that 84.5% of patients were positive for HPV DNA. The most prevalent HPV genotypes were high-risk HPV 16 and 18 in single or co-infections. Expression of TGF-beta1 decreased as tumor cells progressed from cervical intraepithelial neoplasia to cervical carcinoma. Furthermore, we observed that cervical lesions without HPV infection expressed significantly less TGF-beta1. TGF-betaRI and Smad2 gene expression levels were found to be decreased in SCC and AC samples in contrast with CIN1 and CIN2/3 samples. Our results showed that in human cervical cancer the disruption of TGF-beta/Smad signalling pathway might contribute to the malignant progression of cervical dysplasia. These data emphasize the importance of canonical TGF-beta pathway integrity in carcinogenesis.

Botezatu A.,Romanian Academy Stefan S Nicolau Virology Institute | Goia-Rusanu C.D.,Romanian Academy Stefan S Nicolau Virology Institute | Iancu I.V.,Romanian Academy Stefan S Nicolau Virology Institute | Huica I.,Romanian Academy Stefan S Nicolau Virology Institute | And 4 more authors.
Molecular Medicine Reports | Year: 2011

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 (Ir)-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.

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