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

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.