Objective To study the clinical risk factors and the characteristics of cerebral magnetic resonance imaging (MRI) of hypoxic-ischemia encephalopathy (HIE) in full-term infants in high-altitude area.Method From January 2014 to December,2016 full-term Tibetan infants with HIE and healthy full-term Tibetan infants admitted to our hospital were enrolled in the study.General conditions and perinatal status were retrospectively analyzed.Univariate analysis and multivariate analysis were used to determine the risk factors of the HIE.MRI characteristics,location of the brain injuries and the correlation between HIE clinical grading and MRI grading were analyzed.Result During the study period,5 172 full-term Tibetan neonates were born in our hospital,198 of them were diagnosed of HIE and the incidence was 3.8％.According to HIE clinical grading,31 were mild,110 were moderate and 57 were severe.MRI grading included 34 mild,131 moderate and 33 severe.The main manifestations of MRI included white matter injury,especially subcortical white matter injury of frontal,parietal and occipital lobes,gray matter injury and diffuse cerebral edema.Mild HIE had a certain correlation with MRI grading,however,severe HIE had poor correlation with MRI grading.Multivariate Logistic regression analysis showed that abnormal birth weight (＜2 500 g or＞4 000 g) and intrauterine distress were independent risk factors of HIE in full-term Tibetan neonates[OR (95％ CI):3.663 (1.961～6.843) and 5.419 (2.487～11.807)].Conclusion Macrosomia at birth,low birth weight and intrauterine distress are independent risk factors of HIE in Tibetan full-term neonates in Lhasa.White matter injury is the main MRI manifestation of HIE.Clinical grading of Mild HIE has good consistency with the MRI grading,but MRI grading is milder than the clinical grading for those with moderate and severe HIE.

Objective To investigate the mechanism of metformin for regulating tumor-stromal cell cross-talk in breast cancer.Methods Tumor associated fibroblasts(CAFs)co-cultured with breast cancer cells were treated with metformin,and the changes in expressions of hypoxia-inducible factor-1α(HIF-1α),p-AMPK,stroma-derived factor-1(SDF-1)and interleukin-8(IL-8)in the CAFs were detected using ELISA,RT-qPCR or Western blotting;Transwell assay was used to evaluate the invasiveness of the tumor cells and its changes following treatment with exogenous SDF-1,IL-8 and TGF-β1.The effects of HIF-1α shRNA or overexpression plasmid,AMPK shRNA,and treatment with OG(a proline hydroxylase inhibitor)or 2-OXO(a proline hydroxylase activator)were examined on p-AMPK,HIF-1α,SDF-1 and IL-8 expressions and invasiveness of the CAFs.Results Metformin treatment significantly increased the expression levels of p-AMPK,SDF-1 and IL-8(P<0.05)and decreased HIF-1α expression(P<0.05)without affecting AMPK expression level(P>0.05)in the CAFs.The invasion ability of metformin-treated breast cancer cells was significantly decreased(P<0.05).Exogenous SDF-1 and IL-8,HIF-1α overexpression,and OG-induced upregulation of HIF-1α all significantly attenuated the inhibitory effects of metformin on breast cancer cell invasion(P<0.05)and HIF-1α,SDF-1 and IL-8 expressions in CAFs(P<0.05).Transfection with HIF-1α shRNA or treatment with 2-OXO significantly decreased the invasiveness of breast cancer cells(P<0.05).P-AMPK knockdown significantly suppressed the inhibitory effect of metformin on HIF-1α expression in CAFs and on invasion of breast cancer cells(P<0.05).Treatment with TGF-β1 partially decreased the inhibitory effect of metformin on HIF-1α expression in CAFs and invasiveness of the breast cancer cells(P<0.05).Conclusion Metformin suppresses HIF-1α expression in CAFs to block tumor-stromal cross talk in breast cancer.

Objective To explore the regulation of DIRAS2 gene expression by acetylated STAT3 and its involvement in the proliferation of triple-negative breast cancer(TNBC)cells.Methods The expression levels of DIRAS2 and acetylated STAT3 in TNBC tissues and cells were analyzed by database query,Western blotting,and qRT-PCR.TNBC cell lines MDA-MB-231 and SUM159 were selected,and lentivirus or plasmid was used to construct DIRAS2 overexpression and STAT3 wild or Lys685 mutation cell lines.The CCK-8 assay was used to evaluate the effect of DIRAS2 and STAT3 acetylation on the proliferation of TNBC cells.Western blotting,pyrosequencing,ChIP and IP were employed to investigate the regulatory effect and mechanism of acetylated STAT3 on DIRAS2 expression.Results The expression of DIRAS2 was decreased in TNBC tissues and cells.Pyrosequencing analysis found that the methylation level of CpG islands in the DIRAS2 promoter was increased in TNBC cells compared with normal breast epithelial cells,which promoted the growth of cancer cells.Furthermore,TNBC cells showed an increase in STAT3 acetylation,which was accompanied by a shift in the methylation status of the DIRAS2 promoter.ChIP and IP experiments showed that acetylated STAT3 could bind to the DIRAS2 promoter,and the STAT3 Lys685 mutation disrupted the interaction between STAT3 and DNMT1.Conclusion Acetylated STAT3 induces DIRAS2 promoter methylation by recruiting DNMT1,leading to loss of DIRAS2 expression and cancer cell proliferation in TNBC.

Objective To investigate the mechanism of metformin for regulating tumor-stromal cell cross-talk in breast cancer.Methods Tumor associated fibroblasts(CAFs)co-cultured with breast cancer cells were treated with metformin,and the changes in expressions of hypoxia-inducible factor-1α(HIF-1α),p-AMPK,stroma-derived factor-1(SDF-1)and interleukin-8(IL-8)in the CAFs were detected using ELISA,RT-qPCR or Western blotting;Transwell assay was used to evaluate the invasiveness of the tumor cells and its changes following treatment with exogenous SDF-1,IL-8 and TGF-β1.The effects of HIF-1α shRNA or overexpression plasmid,AMPK shRNA,and treatment with OG(a proline hydroxylase inhibitor)or 2-OXO(a proline hydroxylase activator)were examined on p-AMPK,HIF-1α,SDF-1 and IL-8 expressions and invasiveness of the CAFs.Results Metformin treatment significantly increased the expression levels of p-AMPK,SDF-1 and IL-8(P<0.05)and decreased HIF-1α expression(P<0.05)without affecting AMPK expression level(P>0.05)in the CAFs.The invasion ability of metformin-treated breast cancer cells was significantly decreased(P<0.05).Exogenous SDF-1 and IL-8,HIF-1α overexpression,and OG-induced upregulation of HIF-1α all significantly attenuated the inhibitory effects of metformin on breast cancer cell invasion(P<0.05)and HIF-1α,SDF-1 and IL-8 expressions in CAFs(P<0.05).Transfection with HIF-1α shRNA or treatment with 2-OXO significantly decreased the invasiveness of breast cancer cells(P<0.05).P-AMPK knockdown significantly suppressed the inhibitory effect of metformin on HIF-1α expression in CAFs and on invasion of breast cancer cells(P<0.05).Treatment with TGF-β1 partially decreased the inhibitory effect of metformin on HIF-1α expression in CAFs and invasiveness of the breast cancer cells(P<0.05).Conclusion Metformin suppresses HIF-1α expression in CAFs to block tumor-stromal cross talk in breast cancer.