MicroRNA hsa-miR-29 was connected to a number of malignancies. Its target genes are many, among them Mcl-1 that is expressed in three possible isoforms, one of which is anti-apoptotic and another one pro-apoptotic. Ratio of these two isoforms appears to affect cell response to external stimuli. We have demonstrated that miR-29b enhanced etoposide toxicity in HeLa cell line by modulating this ratio of Mcl-1 isoforms. However, it is not known whether the described miR-29 effect is common to various cancer types or even have the opposite effect. This represents a significant problem for possible future applications. In this report, we demonstrate that miR-29b affects toxicity of 60 μM etoposide in cell lines derived from selected malignancies. The mechanism, however, differs among the cell lines tested. Hep G2 cells demonstrated similar effect of miR-29b on etoposide toxicity as was described in HeLa cells, i.e. modulation of Mcl-1 expression. Target protein down-regulated by miR-29b resulting in enhanced etoposide toxicity in Caco-2 cells was, however, Bcl-2 protein. Moreover, H9c2, Hek-293 and ARPE-19 cell lines selected as a representatives of non-malignant cells, showed no effect of miR-29b on etoposide toxicity. Our data suggest that miR-29b could be a common enhancer of etoposide toxicity in malignant cells due to its modulation of Bcl family proteins.

• MeSH
• apoptóza účinky léků   genetika   MeSH
• buňky Hep G2 MeSH
• Caco-2 buňky MeSH
• etoposid * toxicita   farmakologie   MeSH
• fytogenní protinádorové látky farmakologie   toxicita   MeSH
• HEK293 buňky MeSH
• HeLa buňky MeSH
• lidé MeSH
• mikro RNA * genetika   metabolismus   MeSH
• protein MCL-1 * genetika   metabolismus   MeSH
• protoonkogenní proteiny c-bcl-2 genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Etoposide is commonly used as a monotherapy or in combination with other drugs for cancer treatments. In order to increase the drug efficacy, ceaseless search for novel combinations of drugs and supporting molecules is under way. MiRNAs are natural candidates for facilitating drug effect in various cell types. We used several systems to evaluate the effect of miR-29 family on etoposide toxicity in HeLa cells. We show that miR-29b significantly increases etoposide toxicity in HeLa cells. Because Mcl-1 protein has been recognized as a miR-29 family target, we evaluated downregulation of Mcl-1 protein splicing variant expression induced by miR-29 precursors and confirmed a key role of Mcl-1 protein in enhancing etoposide toxicity. Despite downregulation of Mcl-1 by all three miR-29 family members, only miR-29b significantly enhanced etoposide toxicity. We hypothesized that this difference may be linked to the change in Mcl-1L/Mcl-1S ratio induced by miR-29b. We hypothesized that the change could be due to miR-29b nuclear shuttling. Using specifically modified miR-29b sequences with enhanced cytosolic and nuclear localization we show that there is a difference, albeit statistically non-significant. In conclusion, we show that miR-29b has the synergistic effect with etoposide treatment in the HeLa cells and that this effect is linked to Mcl-1 protein expression and nuclear shuttling of miR-29b.

• MeSH
• buněčný cyklus účinky léků   MeSH
• down regulace MeSH
• etoposid toxicita   MeSH
• fytogenní protinádorové látky toxicita   MeSH
• HeLa buňky MeSH
• lidé MeSH
• mikro RNA metabolismus   MeSH
• protein MCL-1 genetika   metabolismus   MeSH
• viabilita buněk účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH