Nucleophosmin (NPM), a multifunctional nucleolar phosphoprotein is dysregulated in human malignancies leading to anti-apoptosis and inhibition of differentiation.We evaluated the precise three-dimensional structure of NPM based on the highly conserved structure of Xenopus NO38 and its requirement to form dimers and pentamers via its N-terminal domain (residues, 1-107). We hypothesized that a small molecular inhibitor (SMI) that could disrupt the formation of dimers would inhibit aberrant NPM function(s) in cancer cells. Molecular modeling, pharmacophore design, in silico screening and interactive docking identified NSC348884 as a putative NPM SMI that disrupts a defined hydrophobic pocket required for oligomerization. NSC348884 inhibited cell proliferation at an IC 50 of 1.7-4.0 lM in distinct cancer cell lines and disrupted NPM oligomer formation by native polyacrylamide gel electrophoresis assay. Treatment of several different cancer cell types with NSC348884 upregulated p53 (increased Ser15 phosphorylation) and induced apoptosis in a dose-dependent manner that correlated with apoptotic markers: H2AX phosphorylation, poly(ADPribose) polymerase cleavage and Annexin V labeling. Further, NSC348884 synergized doxorubicin cytotoxicity on cancer cell viability. The data together show that NSC348884 is an SMI of NPM oligomer formation, upregulates p53, induces apoptosis and synergizes with chemotherapy. Hence, an SMI to NPM may be a useful approach to anticancer therapy.

Lactic acid bacteria (LAB) and their exopolysaccharides (EPS) are recognized to promote intestinal barrier function by mechanisms that remain incompletely understood. Herein, we sought to identify the roles of exopolysaccharides from Lactobacillus plantarum NCU116 (EPS116) in intestinal barrier function. Our data showed that EPS116 attenuated dextran sodium sulfate (DSS) induced colitis and promoted epithelial barrier function and the expression of tight junction (TJ) proteins in vivo and in vitro. Moreover, chromatin immunoprecipitation data showed that EPS116 facilitated STAT3 (signal transducer and activator of transcription 3) binding to the promoter of occludin and ZO-1. Furthermore, knockdown of STAT3 in Caco-2 cell with EPS116 treatment led to decreased expression of occludin and ZO-1 and increased intestinal permeability, suggesting that the regulation of epithelial barrier function by EPS116 should be STAT3 dependent. Thus, our data revealed a novel mechanism that EPS116 inhibited intestinal inflammation via regulating intestinal epithelial barrier function.

Regeneration of epithelia is crucial for maintaining the intestinal barrier and homeostasis. Our previous work showed that exopolysaccharides from Lactobacillus plantarum NCU116 (EPS116) regulated the barrier function and homeostasis of the intestine; however, the relevant mechanisms remain obscure. Therefore, we sought to explore the role of EPS116 in promoting intestinal epithelial regeneration. Our data showed that the administration of EPS116 markedly ameliorated inflammatory bowel disease-related phenotypes and promoted the regeneration of crypts in the colon of colitis mice. The results of immunofluorescence and reverse transcription-quantitative polymerase chain reaction experiments indicated that EPS116 strikingly increased the number of intestinal stem cells (ISCs) and the expression of differentiation markers for goblet cells, enterocytes, and enteroendocrine cells in the mouse colon. Intestinal microbiota analysis showed that EPS116 increased microbial populations associated with intestinal regeneration and glycan metabolism. Therefore, the present study revealed a novel model that EPS116 promoted the intestinal homeostasis through modulating the proliferation and differentiation of ISCs and altering the gut microbiota profile.