Graphene Oxide Dysregulates MiR-21 Expression in Breast Cancer MCF-7 Cell Line

Background and Aim: Inhibition of microRNA-21 (miR-21) has emergedas a promising therapeutic strategy for many malignancies includingbreast cancer. Graphene oxide (GO) has been used as a suitable carrierfor drug delivery due to its unique properties which include large surfacearea and capability of chemical modifications. However, the molecularbasis for in vivo and in vitro GO toxicity has been remained uncleartill now. Recent studies have detected changes in miRNAs expressionafter exposure to GO. In this study, the cytotoxicity effect of GO on theexpression of miR-21 in MCF-7 cells has been investigated.Methods: The cytotoxicity of GO was quantitatively evaluated by MTTassay. MCF- 7 Cells were seeded in 96-well plates and were treatedwith different concentrations (5,10, 20, 40, 80, 160 μg/mL) of GO for24 h. Then cells were incubated with GO for 24 hours and were stainedwith PI and Hoechst 33324 and analyzed by fluorescence microscopy.Furthermore, the expression of miR-21 was analyzed in incubated MCF-7 Cells with GO by Real-Time PCR technique.Results: Our results indicated that GO has no cytotoxicity in MCF-7 cellsup to a concentration of 20 μg/mL. Fluorescence imaging analysis ofHoechst and PI staining revealed that GO did not induce cell apoptosisin the concentration of 15 μg/mL. Real-time PCR result indicated that GOincreased the expression of miR-21 in MCF-7 cells.Conclusion: Although our results showed too little apoptosis in breastcancer MCF-7 cell line exposed to GO at a non-toxic concentration of15μg/mL, we found induction of miR-21 expression after GO treatment.Considering that inhibition of miR-21 is the therapeutic goal, newstrategies such as chemical modification are needed to eliminate thepositive effect of GO on miR-21 expression.

کلیدواژه ها:

Graphene oxide ، MCF-7 cells ، miR-21 ، Apoptosis