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Objective·To construct a prognosis-associated microRNA (miRNA) prediction model in gastric cancer patients based on bioinformatics analysis and evaluate its application value. Methods·The clinicopathological data of gastric cancer patients were downloaded from the Cancer Genome Atlas (TCGA). There were 258 males and 139 females with a median age of 67 years. Three hundred and fifty-six of the 397 patients had complete clinicopathological data. The 397 patients were allocated into training cohort consisting of 278 patients and validation cohort consisting of 119 patients using the random sampling method, with a ratio of 7:3. A miRNA sequencing dataset GSE93415 containing 20 pairs of gastric cancer and corresponding adjacent normal tissue was downloaded from Gene Expression Omnibus database. The candidate miRNAs were selected from differentially expressed miRNAs in gastric cancer and adjacent tissue. A prognosis associated miRNA prediction model was constructed upon survival-associated miRNAs which were selected from candidate miRNAs through LASSO-Cox regression analysis. The performance of prognosis-associated miRNA prediction model was validated in the training cohort and validation cohort. The reliability of the model was evaluated by using Log-Rank test, and the accuracy of the model was evaluated by using the area under curve (AUC) of the receiver operating characteristic curves. Gene expression profiles and algorithms in the pRRophetic package were utilized to predict patients' sensitivity to chemotherapy drugs. Calibration curves were used to verify the accuracy of the nomogram. Consistency index (C-index) was used to check the consistency of the nomogram and other factors. Decision curve analysis (DCA) was employed to predict the contribution of candidate factors to clinical decision making. Results· 1 There was no significant difference in the baseline and overall survival between the training cohort and validation cohort (P>0.05). 2 There were 111 differentially expressed miRNAs calculated from GSE93415 dataset, of which 20 were up-regulated in tumor tissue while 91 were down-regulated. Fifty-nine miRNAs were selected as candidate miRNAs after filtration. 3 Among the 59 candidate miRNAs, 5 survival-associated miRNAs were selected, including let-7i-5p, let-7f-5p, miR-708-5p, miR-135b-5p and miR-100- 5p. The differential expression patterns of gastric cancer to adjacent tissue were all down-regulation, with the fold change of 2.55, 2.78, 2.17, 3.08 and 3.26. Risk score = ( -0.049xlet-7i-5p expression level -0.033 2xlet-7f-5p expression level +0.202 9xmiR-708-5p expression level -0.088 9xmiR-135b-5p expression level +0.016 3xmiR-100-5p expression level). 4 In the training cohort and the validation cohort, the overall survival rate of patients in the highrisk group was lower, and the difference was statistically significant (P<0.05) . The AUC of the prognosis-associated miRNA model for 1-, 3- and 5-year survival prediction was 0.640, 0.763 and 0.853, and was 0.631, 0.735 and 0.750 in validation cohort. 5 Results of univariate analysis showed that age, tumor pathological stage, T stage, N stage, M stage and prognosis-associated miRNA model score were related factors for prognosis of gastric cancer patients (HR=1.017, 1.633, 1.353, 1.346, 2.652, 15.874; 95%CI 1.002-1.033, 1.333-2.001, 1.109-1.650, 1.169-1.548, 1.553-4.529, 5.729-43.985; P< 0.05). Results of multivariate analysis showed that age, M stage and prognosis-associated miRNA model score were independent risk factors for prognosis of gastric cancer patients (HR=1.03, 2.27, 18.72; 95%CI 1.01-1.05, 1.09-4.70, 5.96-58.77; P<0.05). 6The AUC of the prognosis-associated miRNA model for 5-year survival prediction was 0.818 in 356 gastric cancer patients with complete clinicopathological data, higher than that of age, gender, tumor pathological stage, T stage, N stage, M stage and merged clinical factors. 7 The results of Calibration curves, C-index, and DCA all indicated that patients with gastric cancer may get more net benefits from the prognostic nomogram than age, gender and tumor pathological stage. Conclusion·A prognosisassociated miRNA prediction model that can be used to predict the survival of gastric cancer patients is constructed based on 5 miRNAs, which has a certain predictive ability to distinguish the survival status and prognosis of gastric cancer patients and can provide reference for clinical treatment. [ABSTRACT FROM AUTHOR]

This paper aimed to investigate the effect of total flavonoids of buckwheat flower and leaf on myocardial cell apoptosis and Wnt/β-catenin/peroxisome proliferator-activated receptor γ(PPARγ) pathway in arrhythmic rats. SD rats were randomly divided into a control group, a model group, a low-dose(20 mg·kg~(-1)) group of total flavonoids of buckwheat flower and leaf, a medium-dose(40 mg·kg~(-1)) group of total flavonoids of buckwheat flower and leaf, a high-dose(80 mg·kg~(-1)) group of total flavonoids of buckwheat flower and leaf, a propranolol hydrochloride(2 mg·kg~(-1)) group, with 12 rats in each group. Except the control group, rats in other groups were prepared as models of arrhythmia by sublingual injection of 1 mL·kg~(-1) of 0.002% aconitine. After grouping and intervention with drugs, the arrhythmia, myocardial cells apoptosis, myocardial tissue glutathione peroxidase(GSH-Px), catalase(CAT), malondialdehyde(MDA), serum interleukin-6(IL-6), prostaglandin E2(PGE2) levels, myocardial tissue apoptosis, and Wnt/β-catenin/PPARγ pathway-related protein expression of rats in each group were measured. As compared with the control group, the arrhythmia score, the number of ventricular premature beats, ventricular fibrillation duration, myocardial cell apoptosis rate, MDA levels in myocardial tissues, serum IL-6 and PGE2 levels, Bax in myocardial tissues, and Wnt1 and β-catenin protein expression levels increased significantly in the model group, whereas the GSH-Px and CAT levels, and Bcl-2 and PPARγ protein expression levels in myocardial tissues reduced significantly. As compared with the model group, the arrhythmia score, the number of ventricular premature beats, ventricular fibrillation duration, myocardial cell apoptosis rate, MDA leve in myocardial tissues, serum IL-6 and PGE2 levels, Bax in myocardial tissues, and Wnt1 and β-catenin protein expression levels reduced in the drug intervention groups, whereas the GSH-Px and CAT levels and Bcl-2 and PPARγ protein expression levels in myocardial tissues increased. The groups of total flavonoids of buckwheat flower and leaf were in a dose-dependent manner. There was no significant difference in the levels of each index in rats between the propranolol hydrochloride group and the high-dose group of total flavonoids of buckwheat flower and leaf. The total flavonoids of buckwheat flower and leaf inhibit the activation of Wnt/β-catenin pathway, up-regulate the expression of PPARγ, reduce oxidative stress and inflammatory damage in myocardial tissues of arrhythmic rats, reduce myocardial cell apoptosis, and improve the symptoms of arrhythmia in rats.