Inhibition of Nogo-B reduces the progression of pancreatic cancer by regulation NF-κB/GLUT1 and SREBP1 pathways.

Pancreatic cancer (PC) is a lethal disease and associated with metabolism dysregulation. Nogo-B is related to multiple metabolic related diseases and types of cancers. However, the role of Nogo-B in PC remains unknown. In vitro, we showed that cell viability and migration was largely reduced in Nogo-B knockout or knockdown cells, while enhanced by Nogo-B overexpression. Consistently, orthotopic tumor and metastasis was reduced in global Nogo knockout mice. Furthermore, we indicated that glucose enhanced cell proliferation was associated to the elevation expression of Nogo-B and nuclear factor κB (NF-κB). While, NF-κB, glucose transporter type 1 (GLUT1) and sterol regulatory element-binding protein 1 (SREBP1) expression was reduced in Nogo-B deficiency cells. In addition, we showed that GLUT1 and SREBP1 was downstream target of NF-κB. Therefore, we demonstrated that Nogo deficiency inhibited PC progression is regulated by the NF-κB/GLUT1 and SREBP1 pathways, and suggested that Nogo-B may be a target for PC therapy.

The Wnt3a/ß-catenin/TCF7L2 signaling axis reduces the sensitivity of HER2-positive epithelial ovarian cancer to trastuzumab.

Epithelial ovarian cancer (EOC) is one of the most common and lethal gynecological cancers. Novel therapeutic agents have been developed for EOC, but patient survival remains poor. Trastuzumab has been approved for breast and gastric cancers with high expression of human epidermal growth factor receptor 2 (HER2), but it has not achieved any clinical success in EOC. Dysregulated Wnt/ß-catenin signaling is involved in cancer development, but whether it plays a role in EOC resistance to trastuzumab remains largely unknown. Here, we observed that high expression of Wnt3a, ß-catenin and TCF7L2, which can form a signaling axis in the Wnt/ß-catenin pathway, commonly existed in HER2-positive EOC tissue samples and was correlated with a poor patient prognosis. Cell proliferation and migration assays and nude mouse xenograft model experiments demonstrated that the Wnt3a/ß-catenin/TCF7L2 signaling axis promoted tumor cell growth and metastasis and reduced tumor sensitivity to trastuzumab. Analysis of downstream Akt signaling suggested that the function of the Wnt3a/ß-catenin/TCF7L2 signaling axis was mediated, at least in part, through increasing Akt phosphorylation. Overall, this study reveals a crucial role for the Wnt3a/ß-catenin/TCF7L2 signaling axis in EOC resistance to trastuzumab and the potential application of HER2-targeted drugs combined with inhibitors of this signaling axis for EOC treatment.

Mitochondrial mechanism of heat stress-induced injury in rat cardiomyocyte.

Heat stress results in cardiac dysfunction and even cardiac failure. To elucidate the cellular and molecular mechanism of cardiomyocyte injury induced by heat stress, the changes of structure and function in cardiac mitochondria of heat-exposed Wistar rats and its role in cardiomyocyte injury were investigated. Heat stress induced apoptosis and necrosis of cardiomyocytes in a time- and dose-dependent fashion. In the mitochondria of heat-stressed cardiomyocytes, the respiratory control rate and oxidative phosphorylation efficiency (P:O) were decreased gradually with the rise of rectal temperature. The Ca2+ -adenosine triphosphatase activity and Ca2+ content were also reduced. Exposing isolated mitochondria to the heat stress induced special internal environmental states including Ca2+ overload, oxidative stress, and altered mitochondrial membrane permeability transition (MPT). In vivo, the heat stress-induced mitochondrial MPT alteration was also found. The changes of mitochondrial MPT resulted in the release of cytochrome c from mitochondria into the cytosol, and in turn, caspase-3 was activated. Transfection of bcl-2 caused Bcl-2 overexpression in cardiomyocyte, which protected the mitochondria and reduced the heat stress-induced cardiomyocyte injury. In conclusion, it appears that the destruction of mitochondrial structure and function not only resulted in the impairment of physiological function of cardiomyocytes under heat stress but may also further lead to severe cellular injury and even cell death. These findings underline the contribution of mitochondria to the injury process in cardiomyocytes under heat stress.

[Differentially expressed genes associated with cold acclimation].

To investigate the upregulated genes associated with cold acclimation, a cold acclimation model was established based on Balb/C mouse. mRNA of muscle and liver were isolated, and the upregulated genes of these tissues were studied by representational differential analysis (RDA). The upregulated genes then were sequenced and searched by Blast software in GenBank database. The results showed that some genes were upregulated and possibly associated with cold acclimation. Three of these genes, transferrin, fibrinogen B-beta-chains and a new gene fragment (Genbank ID: AF454762), were confirmed to be upregulated by RNA slot-blot analysis. The finding of these genes might contribute to further understanding of the molecular mechanisms of cold acclimation.

[Study on mitochondrial membrane mechanism of rat heart injury induced by constrainting stress].

OBJECTIVE: To investigate the effect of constrainting stress on biological characters and function of mitochondrial membrane in rat heart and to explore the possible mitochondrial membrane mechanism underlying stress-induced heart injury. METHOD: Stress animal model was established. After constrained for different times, all rats were killed and several indexes were examined. RESULT: Constrainting stress can induce mitochondrial permeability transition, decrease of mitochondrial membrane fluidity, increase of the production of membrane lipid peroxidation and injury of mitochondrial respiratory function which is in time-dependent manner. CONCLUSION: Mitochondrial membrane impairment and its effects are the important mechanism of stress-induced heart injury.