| Popis: |
Background The Hedgehog (Hh) signaling pathway is essential for normal embryonic development, while its hyperactivation in adult organism is associated with development of various cancers, including ovarian cancer. The role of the Hh signaling pathway in ovarian cancer, as well as in certain histological subtypes of ovarian cancer, is poorly understood. Therefore, we investigated the role of PTCH1 protein and changes in the promoter methylation status of the corresponding gene, in a cohort of low- (LGSC) and high-grade (HGSC) serous ovarian carcinomas and HGSC cell lines (OVCAR5, OVCAR8 and OVSAHO). Methods PTCH1 protein expression level was analyzed using immunohistochemistry in tissue samples, and by immunofluorescence and Western blot in cell lines. DNA methylation pattern of PTCH1 gene were analyzed by methylation-specific PCR (MSP). Mann-Whitney U test was used to compare differences in expression of PTCH1 protein among ovarian tumor samples compared with normal tissue samples, while Spearman’s correlation was used to test the association between DNA promoter methylation of the PTCH1 gene and expression of the corresponding protein. Results PTCH1 protein expression level was significantly higher in HGSCs and LGSCs compared with control tissues (healthy ovaries and fallopian tubes). Similarly, cancer cell lines exhibited significantly higher PTCH1 protein expression in comparison with normal fallopian tube non-ciliated epithelium cell line (FNE1). Nuclear localization of the PTCH1 protein in tumor tissue and cultured tumor cells suggests that this protein could play an active tumor promoter role in the nuclei of serous ovarian carcinoma cells. PTCH1 protein fragments of different molecular weights were detected in the cell lines, indicating possible proteolytic cleavage of this protein, resulting in the generation of soluble N-terminal fragments that are translocated to the nucleus. DNA methylation of the PTCH1 gene promoter was not in line with the expression level of this protein, suggesting that possibly other mechanisms, either epigenetic or posttranslational, regulate PTCH1 gene expression and protein level in serous ovarian carcinomas. Conclusions Our results indicate that PTCH1 protein could play an active tumor promoter role in the pathogenesis of serous ovarian carcinoma. |
