Modifying Effects of 5-Azacytidine on Metal-Containing Proteins Profile in Guerin Carcinoma With Different Sensitivity to Cytostatics

Abstract

Aim: To assess the influence of the treatment with 5-azacytidine (5-aza) on the profile of metal-containing proteins and factors of their regulation in Guerin carcinoma cells in vivo. Materials and Methods: The study was conducted on Wistar rats transplanted with wild-type Guerin carcinoma (Guerin/WT) and its strains resistant to cisplatin (Guerin/CP) or doxorubicin (Guerin/Dox). Animals were distributed in 6 groups treated with 5-aza and control animals without treatment. 5-Aza was injected by i.v. route (1 injection in 4 days at a dose of 2 mg/kg starting from the 4th day after tumor transplantation, 4 injections in total). Ferritin levels in blood serum and tumor tissue were measured by ELISA, transferrin and free iron complexes — by low-temperature EPR, miRNA-200b, -133a and -320a levels and promoter methylation — by real-time quantitative reverse transcription polymerase chain reaction. Results: The study has shown that 5-aza treatment caused demethylation of promoter regions of fth1 and tfr1 genes in all studied Guerin carcinoma strains. 5-Aza treatment resulted in a significant decrease of ferritin levels in tumor tissue (by 32.1% in Guerin/WT strain, by 29.8% in Guerin/Dox and by 69.1% in Guerin/CP). These events were accompanied by 3.5-fold and 2-fold increase of free iron complexes levels in tumor tissue of doxorubicin and cisplatin resistant strains, respectively. Also, 5-aza treatment resulted in significantly elevated levels of miR-200b, -133a, 320a expression in tumor tissue. After 5-aza treatment, ferritin levels in blood serum of animals with Guerin/Dox were increased by 23.9%, while in Guerin/Wt and Guerin/CP they were decreased by 17 and 16%, respectively. Conclusion: Alterations of epigenetic regulation upon in vivo treatment with 5-aza change the levels of metal-containing proteins due to DNA demethylation and altered miRNA expression profiles in Guerin carcinoma cells.

DNA methylation‐regulated and tumor‐suppressive roles of miR‐487b in colorectal cancer via targeting MYC, SUZ12, and KRAS

“…For instance, 5-Aza contributes to the upregulation of miR-212 in gastric cancer, 40 leading to the inhibition of MYC expression. 5-Aza can also markedly reverse the aberrant level of miR-200b, 41 which may inhibit SUZ12 in cholangiocarcinoma. 42 By removing the hypermethylation on the promoter regions of miR-134, 43 miR-181c, 44 and miR-193b, 45 5-Aza can restrain KRAS expression in the glioma, gastric carcinogenesis, and esophageal adenocarcinoma, respectively.…”