Silencing of NAC1 Expression Induces Cancer Cells Oxidative Stress in Hypoxia and Potentiates the Therapeutic Activity of Elesclomol.

In order to survive under conditions of low oxygen, cancer cells can undergo a metabolic switch to glycolysis and suppress mitochondrial respiration in order to reduce oxygen consumption and prevent excessive amounts of reactive oxygen species (ROS) production. Nucleus accumbens-1 (NAC1), a nuclear protein of the BTB/POZ gene family, has pivotal roles in cancer development. Here, we identified that NAC1-PDK3 axis as necessary for suppression of mitochondrial function, oxygen consumption, and more harmful ROS generation and protects cancer cells from apoptosis in hypoxia. We show that NAC1 mediates suppression of mitochondrial function in hypoxia through inducing expression of pyruvate dehydrogenase kinase 3 (PDK3) by HIF-1α at the transcriptional level, thereby inactivating pyruvate dehydrogenase and attenuating mitochondrial respiration. Re-expression of PDK3 in NAC1 absent cells rescued cells from hypoxia-induced metabolic stress and restored the activity of glycolysis in a xenograft mouse model, and demonstrated that silencing of NAC1 expression can enhance the antitumor efficacy of elesclomol, a pro-oxidative agent. Our findings reveal a novel mechanism by which NAC1 facilitates oxidative stress resistance during cancer progression, and chemo-resistance in cancer therapy.

[Preparation of two mouse anti-human PD-1 monoclonal antibodies and identification of their biological characteristics].

AIM: To prepare mouse anti-human PD-1 monoclonal antibodies (mAbs) and identify their biological characteristics. METHODS: The BALB/c mice were immunized with the transfected cell line PD-1/L929. The cells were fused with Sp2/0 using monoclonal antibody techniques and the positive clones were screened by FCS with PD-1/L929. The secreted anti-PD-1 mAbs were identified through rapid isotyping analysis, karyotype analysis, Western blot, competitive inhibition test, indirect immunofluorescence assay, and tumor cell lines detection. RESULTS: Two mouse anti-human PD-1 hybridomas were obtained and their secreted mAbs were named (1F2 and 5F10). Their biological characteristics suggested that they could recognize a protein with approximate molecular weight 55 000 on PD-1/L929 cell lines and different epitopes. 1F2 could recognize PD-1 molecules expressed on SKHep-1 and 7721 while 5F10 could recognize Raji cells. CONCLUSION: Two mouse anti-human PD-1 hybridoma cell lines and their secreted monoclonal antibodies have been successfully obtained and identified.

[Effect of total glucosides of Centella asiatica on antagonizing liver fibrosis induced by dimethylnitrosamine in rats].

OBJECTIVE: To investigate the anti-liver fibrosis effect of total glucosides of Centella asiatica (GCA) in experimental rats. METHODS: Rat liver fibrosis model was induced by injecting dimethylnitrosamine (DMN) intraperitoneally for 6 weeks. Rats were randomly divided into 6 groups, the normal group, the model group, the positive control group treated by colchicine, and the three GCA groups treated by high, moderate and low dosage of GCA through gastrogavage started simultaneously with the modeling. At the end of the experiment, levels of serum total protein (TP), albumin (ALB), alanine transaminase (ALT), aspartate aminotransferase (AST), hyaluronic acid (HA), laminin (LN) were measured, and the pathology of liver tissue was observed. RESULTS: The liver function in the GCA groups was improved, the levels of serum ALT, AST, HA were significantly lower than those in the model group (P < 0.05). Histopathological observation showed that GCA has significant anti-liver fibrosis effect. CONCLUSION: GCA has significant preventive and therapeutic effect on DMN induced liver fibrosis in rats.