Diabetes and periodontal diseases have a mutual promoting relationship that induces severe tissue damage and cell death. The potential roles of microRNAs (miRNAs) and the type of cell death involved in diabetes‐associated periodontitis are obscure. The gingival tissues of patients were obtained and MC3T3‐E1 cells were costimulated with high glucose and lipopolysaccharide (LPS). Osseous morphometric analysis was evaluated with micro‐CT, and histological characteristics were measured by hematoxylin/eosin and immunohistochemical staining. Cytokine secretion was confirmed by enzyme‐linked immunosorbent assay, and reactive oxygen species (ROS) was measured using a DCFH‐DA probe kit. Gene expression was measured by real‐time quantitative reverse transcription PCR (qRT‐PCR), and protein expression was assessed by Western blot and immunofluorescence analysis. The miR‐214 level, receptor‐interacting serine‐threonine protein (RIP) 1, RIP3, and phospho‐mixed lineage kinase domain‐like (p‐MLKL) protein expression were elevated in the inflamed gingival tissues of diabetes‐associated periodontitis patients, with activating transcription factor 4 (ATF4) expression showing the opposite effect. The high glucose (22 mM) could not induce significant increase of RIP1, RIP3, and p‐MLKL; however, the high glucose and LPS (500‐1000 ng/mL) cotreatment resulted in increase in the number of RIP1, RIP3, and p‐MLKL in MC3T3‐E1 cells. NAC (ROS inhibitor) inhibited RIP1, RIP3, and increased ATF4; however, necrostatin‐1 (Nec‐1) (RIP1 inhibitor) specifically inhibited the protein expression of RIP1 and RIP3 and had no influence on ATF4. The use of antagomir‐214 suppressed the expression of miR‐214, RIP1, RIP3, and p‐MLKL, but increased ATF4 protein level in glucose and LPS‐induced cells. ATF4 knockdown by ATF4 small interfering RNA offset the effect of antagomir‐214. RIP1‐ and RIP3‐dependent necroptosis was confirmed in the inflamed gingival tissues of diabetes‐associated periodontitis patients and high glucose‐ and LPS‐ cotreated cells. It was suggested that miR‐214‐targeted ATF4 participated in the regulation of necroptosis in vivo and in vitro.

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Background: MicroRNAs (miRNAs) are widely believed to be promising targets for oral squamous cell carcinoma (OSCC) gene therapy. miR-214 has been identified as a promoter of OSCC aggression and metastasis. Methods: Graphene oxide-polyethylenimine (GO-PEI) complexes were prepared and loaded with a miRNA inhibitor at different N/P ratios. The transfection efficiency of GO-PEI-inhibitor was tested in Cal27 and SCC9 cells. Moreover, the tumor inhibition ability of GO-PEI-inhibitor was measured in an OSCC xenograft mouse model by intratumoral injection. Results: Here, we show that a GO-PEI complex efficiently delivers a miR-214 inhibitor into OSCC cells and controls the intracellular release of the miR-214 inhibitor. These results indicate that the GO-PEI-miR-214 inhibitor complex efficiently inhibited cellular miR-214, resulting in a decrease in OSCC cell invasion and migration and an increase in cell apoptosis by targeting PTEN and p53. In the xenograft mouse model, the GO-PEI-miR-214 inhibitor complex significantly prevented tumor volume growth. Conclusion: This study indicates that functionalized GO-PEI with low toxicity has promising potential for miRNA delivery for the treatment of OSCC.

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