OBJECTIVES:Spindle and kinetochore-associated protein 1(SKA1), originally identified as a protein essential for proper chromosome segregation, has been recently linked to multiple malignancies. This study aimed to explore the biological, clinical role and molecular mechanism of SKA1 in pancreatic carcinogenesis.MATERIALS AND METHODS:SKA1 expression was detected in 145 pancreatic ductal adenocarcinoma (PDAC) specimens by immunohistochemistry. Biological behaviour assays were used to determine the role of SKA1 in PDAC progression in vitro and in vivo. Using isobaric tags for relative and absolute quantitation (iTRAQ), SKA1's downstream proteins were examined. Moreover, cytochalasin B and ZCL278 were used to explore the changes of SKA1-induced signalling and cell morphology, with further confirmation by immunoblotting and immunofluorescence assays.RESULTS:Increased SKA1 expression was significantly correlated with tumour size and cellular differentiation degree in PDAC tissues. Furthermore, elevated levels of SKA1 reflected shorter overall survival (P = .019). As for biological behaviour, SKA1 acted as a tumour promotor in PDAC, overexpression of SKA1 facilitates cell proliferation, migration and invasion in vitro and in vivo. Mechanistically, we demonstrated that SKA1 enhanced pancreatic cancer aggressiveness by inhibiting G2/M arrest and regulating actin cytoskeleton organization via activating Cdc42.CONCLUSIONS:This study revealed novel roles for SKA1 as an important regulator of actin cytoskeleton organization and an oncogene in PDAC cells, which may provide insights into developing novel therapeutics.

Wnt1 inducible signaling pathway protein-1 (WISP1) may play an important role in promoting carcinogenesis. However, the biological function and underlying mechanism of WISP1 in pancreatic carcinogenesis still remains enigmatic. In this study, immunochemistry staining showed that protein levels of WISP1 were more significantly upregulated in pancreatic ductal adenocarcinoma (PDAC) tissues with Tp53 mutation than in PDAC tissues with Tp53 wild-type. In addition, a significant correlation was observed between increased malignant phenotype of tumors from well-differentiated adenocarcinoma tissues to moderately- or poorly-differentiated adenocarcinoma tissues shifting from cytoplasmic expression to nuclear accumulation of WISP1. Interestingly, WISP1 expression was correlated with the poor prognosis in PDAC patients with Tp53 mutation. Also, the biological function analysis showed that WISP1 may act as a potential oncogene in PDAC cells. In addition, immunofluorescence analysis showed that Tp53 mutation promoted WISP1 expression in PanIN and PDAC cells, while Siah E3 Ubiquitin Protein Ligase 1 (Siah1) inhibited WISP1 expression in PDAC cells. Moreover, through immunoprecipitation, immunoblotting analysis, in vitro binding assay, and ubiquitination assay, we found that Tp53 mutation inhibited ubiquitination and degradation of Siah1-dependent WISP1. Therefore, Tp53 mutation-Siah1-WISP1 is a new signaling pathway, playing an important role in pancreatic carcinogenesis.

The EI24 autophagy-associated transmembrane protein is frequently associated with tumor growth and patient survival. In the present study, we found that EI24 was downregulated in pancreatic ductal adenocarcinoma (PDAC) tissues compared with adjacent normal tissues and was associated with cancer cell differentiation. Overexpression of EI24 suppressed cancer cell growth in vitro and in vivo and induced cell cycle S phase arrest, with no impact on caspase-dependent apoptosis. EI24 overexpression also resulted in reduced c-Myc expression, an oncogene in PDAC, accompanied with increased LC3B-II formation, increased Beclin-1, and diminished p62. Together, we propose that EI24 suppresses cell proliferation and prompts cell cycle arrest in pancreatic cancer cells by activating the autophagic lysosomal degradation of c-Myc. Our results suggest a potential mechanism underlying the antitumor effects of EI24 in PDAC and provide insight into the crosstalk between autophagy and cell proliferation involving a possible EI24/Beclin-1/p62/c-Myc signaling pathway.

Objective. This study aimed at investigating the clinical value of magnetic-guided capsule endoscopy (MGCE) in the diagnosis of gastrointestinal diseases in minors. Methods. Eighty-four minor patients hospitalized in the pediatric department at Ruijin Hospital between June 2015 and January 2018 were enrolled for this study. Following bowel preparation, all patients underwent MGCE. The feasibility, safety, diagnostic yield, and sensitivity of MGCE were analyzed. Patients were followed up for more than 2 weeks. Results. The main indications for MGCE in minors were Crohn's disease, gastrointestinal bleeding, and abdominal pain. The main causes of gastric disease were gastric inflammatory hyperplasia, exudative gastritis, and polyps. The most common small bowel diseases in minors were Crohn's disease, Henoch-Schonlein purpura, and polyps. The diagnostic yield in the stomach and small intestine was 13.1% and 28.6%, respectively, and the sensitivity was 100% and 96.0%, respectively. No adverse events occurred. Conclusion. MGCE is a safe, effective, and well-tolerated procedure with good sensitivity and has a potential clinic value for the diagnosis of gastrointestinal diseases in minors.

Pancreatic ductal adenocarcinoma (PanCa) is an extremely lethal disease characterized by mutations of p53 in up to 70% of cases. Our previous studies have confirmed that hyperglycemia may be the first clinical manifestation for the early diagnosis of PanCa. In this article, we showed that targeted knockdown of TG2 or p53 in tumor cells led to decreased cell survival in response to glucose deprivation, while this phenomenon was abolished by combined inhibition of TG2 and p53. We observed that inhibition of TG2 or p53 sensitized glucose deprivation resistance through an intracellular reactive oxygen species (ROS) pathway and the induction of Bcl-2. Moreover, to understand whether pancreatic cancer cells with TG2 and p53 combined interference had possible effects on pancreatic beta cells, we performed studies comparing pancreatic cancer cells with TG2 and p53 combined interference and pancreatic beta cells. We discovered that the supernatant of pancreatic cancer cells with TG2 and p53 combined interference decreased cell survival in pancreatic beta cells. Following the creation of an orthotopic pancreatic cancer mouse model, we revealed glucose tolerance abnormalities in the pancreatic cancer mouse model with TG2 and p53 combined interference, indicating a possible mechanism for damage of beta cells in pancreatic cancer. Taken together, our findings establish roles for TG2 and p53 in response to glucose deprivation in pancreatic cancer cells. The relationship between TG2 and p53 suggests a possible mechanism for glucose tolerance abnormalities-associated pancreatic cancer and could have therapeutic potential for cancer treatment and diagnosis.

Niacin, as an antidyslipidemic drug, elicits a strong flushing response by release of prostaglandin (PG) D2 However, whether niacin is beneficial for inflammatory bowel disease (IBD) remains unclear. Here, we observed niacin administration-enhanced PGD2 production in colon tissues in dextran sulfate sodium (DSS)-challenged mice, and protected mice against DSS or 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis in D prostanoid receptor 1 (DP1)-dependent manner. Specific ablation of DP1 receptor in vascular endothelial cells, colonic epithelium, and myeloid cells augmented DSS/TNBS-induced colitis in mice through increasing vascular permeability, promoting apoptosis of epithelial cells, and stimulating pro-inflammatory cytokine secretion of macrophages, respectively. Niacin treatment improved vascular permeability, reduced apoptotic epithelial cells, promoted epithelial cell update, and suppressed pro-inflammatory gene expression of macrophages. Moreover, treatment with niacin-containing retention enema effectively promoted UC clinical remission and mucosal healing in patients with moderately active disease. Therefore, niacin displayed multiple beneficial effects on DSS/TNBS-induced colitis in mice by activation of PGD2/DP1 axis. The potential efficacy of niacin in management of IBD warrants further investigation.

The importance of Pituitary homeobox 2 (Pitx2) in malignancy remains enigmatic, and Pitx2 has not been previously implicated in pancreatic ductal adenocarcinoma (PDAC). In this study, we performed gene expression profiling of human PDAC tissues and identified Pitx2 as a promising candidate. Pitx2 expression was decreased from 2.6- to 19-fold in human PDAC tissues from microarray units. Immunochemistry staining showed that Pitx2 expression was moderate to intense in normal pancreatic and pancreatic intraepithelial neoplastic lesions, whereas low in human PDAC tissues. The Pitx2 levels correlated with overall patient survival post-operatively in PDAC. Induction of Pitx2 expression partly inhibited the malignant phenotype of PDAC cells. Interestingly, low Pitx2 expression was correlated with Smad4 mutant inactivation, but not with Pitx2 DNA-methylation. Furthermore, Smad4 protein bound to Pitx2 promoter and stimulated Pitx2 expression in PDAC. In addition, Pitx2 protein bound to the promoter of the protein phosphatase 2A regulatory subunit B55α (PPP2R2A) and upregulated PPP2R2A expression, which may activate dephosphorylation of Akt in PDAC. These findings provide new mechanistic insights into Pitx2 as a tumor suppressor in the downstream of Smad4. And Pitx2 protein promotes PPP2R2A expression which may inhibit Akt pathway. Therefore, we propose that the Smad4-Pitx2-PPP2R2A axis, a new signaling pathway, suppresses the pancreatic carcinogenesis.

Cationic polymers readily degradable in response to cellular environment are especially favored as easy-formulating materials to pack siRNA into a nanoparticle and to release the cargo in the cytoplasm in time. In addition to the efficiency of cytosomal release, the degradation products should best be free of safety concerns, a typical challenge for cationic polymers. To satisfy the two criteria, we report a new cationic polymer, polyspermine imine, named as PSP-Imine, which is formed by condensing two endogenous molecules, spermine and glyoxal, through conjugated π linkage, —N═C—C═N— (Schiff base reaction), a poly linkage structure sufficiently stable under neutral condition but dissociative under the endosomal pH. Cellular assays under a confocal microscope indicated that the polyplex formed of PSP-Imine readily released the loaded siRNA to the cytoplasm after being engulfed in the target cells and efficiently silenced the target genes in different cell lines and xenograft mouse model of human cervical carcinoma, as compared with nondegradable PEI 25 kDa. Cell viability assays confirmed that PSP-Imine showed no visible cytotoxicity within the concentration being tested. The present study suggests that PSP-Imine is an excellent siRNA condensing material for forming the core of a therapeutically feasible synthetic carrier system.

Objective: To find a novel nonviral gene vector with a high transfection efficiency and low cytotoxicity.Methods: Polyimine-MPEI is synthesized,then packed with luciferase gene at different mass ratio.The transfection efficiency and cytotoxitity of this polyplex was detected.Results: From mass ratio 5 to 100,the transfection efficiency of the polyplex was above 1.00E+07 and it was relatively ideal.Its cytotoxicity was lower comparing with the PEI25KDa control group and the cell viability was all above the 80%.Conclusions: Polyimine-MPEI is a polycation vector with a bright research prospect,which has high transfection efficiency and low cytotoxicity.Pro-longing the synthesis time and making its molecular weight higher can increase the transfection efficiency.

Objective: To synthesize cross-linked Polyethylenimine derivative with modified procedure and investigate its cytotoxicity and transfection efficiency on COS-7 cells.Methods: PEI-Bu was synthesized by using PEI 800Da as a backbone and 1,4-Dibutanediol Chloroformate was used as a linker.The pDNA condensation ability of the polymer was evaluated by agarose gel electrophoresis.MTT assay was employed to measure the cytotoxicity of the polymer.Luciferase plasmid was used as the reporter gene to investigate transfection efficiency in COS-7 cells.Results: Gel retardation assay showed complete condensation of pDNA at w/w ratios exceeded 1.Cytotoxicity of PEI-Bu increased with the increasing of the concentrations.PEI-Bu showed lower cytotoxicity than PEI 25kDa at the same concentration.Transfection result indicated that the polymer performed the highest transfection efficiency at w/w 5,which was higher than that in commercially available PEI 25kDa(P0.01) and comparable with Lipofectamine 2000(P0.05).Conclusion: The polymer PEI-Bu displayed much lower cytotoxicity and significantly enhanced transfection efficiency than PEI 25kDa in COS-7 cells,Therefore,it would be a promising candidate for safe and efficient gene delivery in gene therapy.

Objective:To investigate the transfection efficiency and cell cytotoxicity of Polyethyleneimine(PEI) derivative linking with glyoxal.Methods:Luciferase plasmid was used as the reporter gene to investigate transfection efficiency in COS-7 cells.Cytotoxicity was detected by MTT method.Results:COS-7 cells transfection and cytotoxicity results suggested that the gene carrier(Polyimine-PEI) was less cytotoxicity than that of PEI25kDa,and expressed equal transfection efficiency with PEI25kDa and Lipofectamine 2000.Conclusion:Polyimine-PEI could be a highly efficient and less toxic gene carrier which was promising in gene therapy.