Folic-Acid-Adorned PEGylated Graphene Oxide Interferes with the Cell Migration of Triple Negative Breast Cancer Cell Line, MDAMB-231 by Targeting miR-21/PTEN Axis through NFκB.

Abstract

Triple negative breast cancer (TNBC), characterized by its aggressive and highly metastatic nature, is difficult to cure by the currently available therapies. In our investigation, folic-acid-adorned PEGylated graphene oxide (FA-PEG-GO) was synthesized by modifying graphene oxide (GO) with folic acid-PEG conjugate (FA-PEG-NH2) by EDC/NHS coupling reaction. FA-PEG-GO exhibited an exceptional potential to attenuate cell migration of TNBC cell line ,MDAMB-231 as compared to GO because of the adorned folic acid moiety, which rendered better targeting. FA-PEG-GO inhibited cell migration by actin depolymerization and perturbing lamellipodia formation. The immunocytochemistry and western blot data unraveled the fact that FA-PEG-GO inhibited cell migration by targeting miR-21 by restricting the nuclear translocation of NFκB. The downregulation of miR-21 resulted in the elevation of PTEN expression which sequentially downregulated pFAK resulting in inhibition of cell migration. Moreover, upregulation of PTEN in FA-PEG-GO treated cells led to the decrease in expression of the downstream regulators including pAkt(Ser473) and pERK1/2, which contributed to the retardation of cell migration. Interestingly, the overexpression of NFκB-p65 by the transfection of NFκB-p65 expression plasmid in TNBC cells reversed the inhibitory effect of FA-PEG-GO on the nuclear translocation of NFκB-p65 which stabilized miR-21 expression and successively downregulated PTEN expression in FA-PEG-GO treated cells. Furthermore, miR-21 overexpression by transfection of miR-21 mimic in turn downregulated PTEN expression and sequentially restored the expression of pFAK even upon FA-PEG-GO treatment. miR-21 overexpression also compensated the inhibitory effect of FA-PEG-GO on pAkt(Ser473) and pERK1/2 which was evident from their significant expression in FA-PEG-GO-treated cells. The studies on chick embryo model ratified the ex ovo antimigratory efficacy of FA-PEG-GO. Altogether, our study unveiled the enormous potential of FA-PEG-GO to attenuate migration of TNBC cell line, MDAMB-231 by targeting the miR-21/PTEN axis through NFκB and thereby providing insights on cancer treatment.