Journal

Bulletin of Experimental Biology and Medicine

Papers (23)

Features of the Copy Number Variation of Certain Genes in Tumor Cells in Patients with Serous Ovarian Adenocarcinoma

We analyzed the peculiarities of the copy number variation of genes that regulate apoptosis, DNA repair, cell proliferation, metabolism, and estrogen reception in tumor and normal cells of high-grade and low-grade serous adenocarcinoma of the ovaries. Using real-time qPCR method, the relative copy number of 34 genes (BAX, BCL2, TP53, MDM2, CASP9, CASP3, CASP7, CASP8, PRKCI, SOX2, OCT4, PIK3, PTEN, C-MYC, SOX18, AKT1, NOTCH1, BRCA1, BRCA2, EXO1, SCNN1A, KRAS, EGFR, BRAF, CYP1A1, CYP1A2, CYP1B1, CYP19A, ESR1, ESR2, GPER, STS, SULT1A, and SULT1E1) was determined in normal and tumor cells of the ovaries extracted by contactless capture laser microsection from FFPE-blocks of 200 patients. The most typical molecular markers of ovarian serous adenocarcinoma cells were identified: copy number of PIK3CA, BCL2, BAX, CASP3, and CASP8 genes. Based on the differences in the gene copy number variation, two molecular subtypes of serous adenocarcinoma were identified, corresponding to two histological subtypes: high-grade (MDM2, SOX2, ESR1, CYP1B1, SULT1E1, TP53, BRCA2) and low-grade (PIK3CA, PTEN, BCL2, BAX, and CASP3). Each of these subtypes was also characterized by molecular heterogeneity and can be subdivided into several subgroups: 3 subgroups for high-grade and 4 subgroups for low-grade serous adenocarcinoma. These findings extend our understanding of the molecular mechanisms of carcinogenesis in the ovarian tissue, confirm molecular difference between the two histological subtypes of serous adenocarcinoma probably underlying their different clinical course.

DNA Methylation of a Group of Long Non-Coding RNA Genes at Different Stages of Ovarian Cancer Dissemination

There are three types of metastases in ovarian cancer: lymphogenous, hematogenous, and peritoneal. Dissemination of the tumor in the peritoneum is directly related with the development of ascites and a poor prognosis. The purpose of this study is to determine changes in the methylation level of a group of long non-coding RNA (lncRNA) genes at different stages of ovarian cancer progression. The methylation level of 7 lncRNA genes (LINC00472, LINC00886, MAFG-DT, SNHG1, SNHG6, TP53TG1, and TUG1) was studied by quantitative methyl-specific PCR in 93 samples of ovarian tumors and 75 paired samples of histologically normal tissue, as well as in 29 peritoneal macroscopic metastases. Using the nonparametric Mann-Whitney test, a significant (p<0.001) increase in the level of methylation of the LINC00886, SNHG1, SNHG6, and TUG1 genes in the tumor tissue was shown. For the LINC00472, LINC00886, and SNHG6 genes, a significant relationship was found with the clinical stage (p≤0.001), as well as with the appearance of metastases for the LINC00472 (p<0.001) and SNHG6 (p=0.005) genes. There was a significant increase in the level of methylation of MAFG-DT and TP53TG1 (p<0.001) genes, as well as a decrease in LINC00886 (p=0.003) in peritoneal metastases relative to the primary focus. Methylation of the LINC00472 and SNHG6 genes can be considered as a factor in initiating ovarian cancer metastasis, and methylation of the LINC00886, MAFG-DT, and TP53TG1 genes as a colonization factor for metastases in the peritoneum. Thus, a relationship between methylation of a group of lncRNA genes at different stages of ovarian cancer dissemination was shown, which is important for understanding the mechanisms of these processes and for developing innovative approaches to ovarian cancer therapy.

Hypermethylation of Genes in New Long Noncoding RNA in Ovarian Tumors and Metastases: A Dual Effect

The role of methylation in the regulation of genes of long noncoding RNA (lncRNA) is still poorly understood. We revealed new hypermethylated lncRNA genes in ovarian tumors and their effect on metastasis of ovarian cancer. A multiple and significant (p<0.001) increase in methylation of a group of lncRNA genes (MEG3, SEMA3B-AS1, ZNF667-AS1, and TINCR) was shown by quantitative methylation-specific PCR using the non-parametric Mann-Whitney test. Moreover, methylation of SEMA3B-AS1, ZNF667-AS1, and TINCR genes in ovarian cancer tumors was detected for the first time. Comparative analysis of 19 samples of peritoneal metastases and paired primary tumors showed a significant decrease in the methylation level of the same 4 genes: MEG3 (p=0.004), SEMA3B-AS1 (p=0.002), TINCR (p=0.002), and ZNF667-AS1 (p<0.001). Reduced methylation of suppressor lncRNA genes in peritoneal metastases is probably associated with the involvement of these lncRNA in the regulation of plastic reversion of the epithelial-mesenchymal transition to the mesenchymal-epithelial transition. Thus, the effect of lncRNA and their methylation on the development of tumors and metastases of ovarian cancer was demonstrated, which is important for understanding of the pathogenesis and mechanisms of metastasis of ovarian cancer. New properties of lncRNA can find application in the development of new approaches in the therapy of ovarian cancer.

Publisher

Springer Science and Business Media LLC

ISSN

0007-4888