Contributions
Abstract: PB1611
Type: Publication Only
Session title: Lymphoma Biology & Translational Research
Background
The p53 protein (a product of the TP53 gene) is known to regulate a whole class of micro-RNAs. The direct target of p53, through which it implements its oncosuppressive effects, is miR-145. This micro-RNA interacts with the 3/ - untranslated mRNA sequence of oncogenes c-MYC and individual cyclinkinases.
Several mechanisms of impaired expression of oncosuppressive micro-RNAs have been described, among which the methylation of promoters and enhancers encoding their genes is important. It is known that the frequency of methylation of the MIR-145 gene differs in various oncological processes. Thus, in patients with prostate cancer and non-small cell lung cancer, the frequency of methylation of this gene is about 50.0 % (Zaman M. S., 2011; Zhiqiang Y., 2015), and in colon cancer – more than 80.0 % (Pekow J., 2015).
It has been shown that a decrease in miR-145 expression is not only associated with the occurrence of lymphomas, but also a predictor of their more aggressive clinical course (Poli V., 2020). However, studies of the methylation status of MIR-145 in diffuse B-large cell lymphoma (DLBCL) have not been previously conducted.
Aims
To evaluate the frequency of methylation of the MIR-145 gene in the tumor tissue of Diffuse Large B-cell Lymphoma.
Methods
Genomic DNA was isolated by phenol-chloroform extraction using guanidine from paraffinized blocks of biopsy samples of tumor lymph nodes and extranodal lesions of patients with DLBCL. The DNA of a healthy donor was used to assess the specificity of methylation. The Human Methylated and Unmethylated DNA Control Kit (Zymo Research, USA) was used as a controls. Bisulfite DNA conversion was performed using the EZ DNA Methylation-Gold Kit (Zymo Research, USA). The methylation status of the gene was determined by the method of methyl-specific PCR using pairs of primers to the methylated and unmethylated sequences.
Results
Currently, 25 DNA samples have been analyzed. It was shown that the frequency of methylation of the MIR-145 gene was 23\25 (92%). In the healthy tissue MIR-145 was also in the methylated state.
Conclusion
The results obtained indicate that the methylation of the MIR-145 gene in the lymphoid tissue of patients with DLBCL is not tumor-nonspecific.
Keyword(s): DLBCL, Methylation
Abstract: PB1611
Type: Publication Only
Session title: Lymphoma Biology & Translational Research
Background
The p53 protein (a product of the TP53 gene) is known to regulate a whole class of micro-RNAs. The direct target of p53, through which it implements its oncosuppressive effects, is miR-145. This micro-RNA interacts with the 3/ - untranslated mRNA sequence of oncogenes c-MYC and individual cyclinkinases.
Several mechanisms of impaired expression of oncosuppressive micro-RNAs have been described, among which the methylation of promoters and enhancers encoding their genes is important. It is known that the frequency of methylation of the MIR-145 gene differs in various oncological processes. Thus, in patients with prostate cancer and non-small cell lung cancer, the frequency of methylation of this gene is about 50.0 % (Zaman M. S., 2011; Zhiqiang Y., 2015), and in colon cancer – more than 80.0 % (Pekow J., 2015).
It has been shown that a decrease in miR-145 expression is not only associated with the occurrence of lymphomas, but also a predictor of their more aggressive clinical course (Poli V., 2020). However, studies of the methylation status of MIR-145 in diffuse B-large cell lymphoma (DLBCL) have not been previously conducted.
Aims
To evaluate the frequency of methylation of the MIR-145 gene in the tumor tissue of Diffuse Large B-cell Lymphoma.
Methods
Genomic DNA was isolated by phenol-chloroform extraction using guanidine from paraffinized blocks of biopsy samples of tumor lymph nodes and extranodal lesions of patients with DLBCL. The DNA of a healthy donor was used to assess the specificity of methylation. The Human Methylated and Unmethylated DNA Control Kit (Zymo Research, USA) was used as a controls. Bisulfite DNA conversion was performed using the EZ DNA Methylation-Gold Kit (Zymo Research, USA). The methylation status of the gene was determined by the method of methyl-specific PCR using pairs of primers to the methylated and unmethylated sequences.
Results
Currently, 25 DNA samples have been analyzed. It was shown that the frequency of methylation of the MIR-145 gene was 23\25 (92%). In the healthy tissue MIR-145 was also in the methylated state.
Conclusion
The results obtained indicate that the methylation of the MIR-145 gene in the lymphoid tissue of patients with DLBCL is not tumor-nonspecific.
Keyword(s): DLBCL, Methylation