Up to date, there has been no molecular signature available in the clinical practice for attention-deficit/hyperactivity disorder (ADHD). To investigate circulating miRNA let-7d significance in ADHD, we investigated serum miRNA let-7d in 35 newly diagnosed ADHD subjects who were randomly selected from 406 patients out of 7450 children, paired with gender- and age-matched control through case-control study. We observed that circulating miRNA let-7d was significantly higher in ADHD subjects than in control (p < 0.05). Higher circulation level of miRNA let-7d was significantly associated with ADHD (odds ratio 16.7; 95% confidence, p < 0.05). Meanwhile, serum galectin-3 level was down-regulated in ADHD subjects and the subjects with low galectin-3 expression accounted for 66% in ADHD. The difference of the serum galectin-3 levels between ADHD and non-ADHD groups reached significance (p < 0.05). In 1-year follow-up, a significantly higher rate of clinical improvement was noted in subjects with low level of circulating miRNA let-7d (p < 0.05) than those with high level of circulating miRNA let-7d. Our data demonstrated that miRNA let-7d was elevated in the serum of ADHD subjects, which might be a novel, useful molecule signature for ADHD.

E-cadherin is often dysregulated in aggressive lung cancer, the mechanism of which cannot always be explained at the level of transcription. In 66 patients with lung cancer, immunohistochemical staining demonstrated that co-localization of E-cadherin and core fucose by Lens culinaris agglutinin was significantly less extensive in tumor than in nontumor tissue. Through gain and loss of fucosylation experiments in the giant lung carcinoma cell lines 95C and 95D, our results revealed that E-cadherin core fucosylation in 95C cells overexpressing α-1, 6-fucosyltransferase (Fut8) inhibited Fut8-95C cell migration, whereas knockdown of Fut8 in 95D cells enhanced migration of short-interfering RNA-targeting Fut8 (siFut8)-95D cells. The level of active Src (phosphorylated Src [Y416]) was significantly reduced in Fut8-95C cells, but elevated in siFut8-95D cells. In protein complexes immunoprecipitated from Fut8-95C cell lysates with anti-E-cadherin, less phosphorylated Src (Y416) and more β-catenin were observed, but immunoprecipitates from siFut8-95D cells, containing less core fucosylated E-cadherin, contained an elevated level of phospho-Src Y416. In Fut8-95C cells, phosphorylation of Akt (Y315, Y326) and GSK-3β (S9) was significantly reduced, but β-catenin (S37) phosphorylation was enhanced. Expression of N-cadherin and Snail1 was also reduced in Fut8-95C cells, but significantly increased in siFut8-95D cells. Intriguingly, when Src kinase activity was inhibited by treatment of cells with PP2 and SU6656, regulation of N-cadherin, Snail1 and cell migration by E-cadherin core fucosylation was abrogated in both Fut8-95C and siFut8-95D cells. Therefore, posttranslational modification of E-cadherin by less core fucosylation recruited and activated Src, and induced an epithelial-mesenchymal transition-like process in lung cancer cells.