ABSTRACT
The involvement of enolase1 (ENO1), intracellularly or extracellularly, has been implicated in cancer development. Moreover, anticancer activities of an ENO1targeting antibody has demonstrated the pathological roles of extracellular ENO1 (surface or secreted forms). However, although ENO1 was first identified as a glycolytic enzyme in the cytosol, to the best of our knowledge, extracellular ENO1 has not been implicated in glycolysis thus far. In the present study, the effects of extracellular ENO1 on glycolysis and other related procancer activities were investigated in multiple myeloma (MM) cells in vitro and in vivo. Knockdown of ENO1 expression reduced lactate production, cell viability, cell migration and surface ENO1 expression in MM cells. Notably, addition of extracellular ENO1 protein in cancer cell culture enhanced glycolytic activity, hypoxiainducible factor 1α (HIF1α) expression, glycolysisrelated gene (GRG) expression and procancer activities, such as cell migration, cell viability and tumorpromoting cytokine secretion. Consistently, these extracellular ENO1induced cellular effects were inhibited by an ENO1specific monoclonal antibody (mAb). In addition, extracellular ENO1mediated glycolysis, GRG expression and procancer activities were also reduced by HIF1α silencing. Lastly, administration of an ENO1 mAb reduced tumor growth and serum lactate levels in an MM xenograft model. These results suggested that extracellular ENO1 (surface or secreted forms) enhanced a HIF1αmediated glycolytic pathway, in addition to its already identified roles. Therefore, the results of the present study highlighted the therapeutic potential of ENO1specific antibodies in treating MM, possibly via glycolysis inhibition, and warrant further studies in other types of cancer.
Subject(s)
Glycolysis , Multiple Myeloma , Humans , Antibodies, Monoclonal/metabolism , Biomarkers, Tumor/metabolism , Cell Line, Tumor , Cell Proliferation/genetics , DNA-Binding Proteins/metabolism , Glycolysis/genetics , Lactates , Multiple Myeloma/genetics , Phosphopyruvate Hydratase/genetics , Phosphopyruvate Hydratase/metabolism , Tumor Suppressor Proteins/metabolism , Animals , Mice , Xenograft Model Antitumor AssaysABSTRACT
A reverse vaccinology-based survey of potent antigens associated with fish nocardiosis was conducted using the largemouth bass, Micropterus salmoides, with an aim to develop subunit vaccines. The antigens selected from the virulent strain Nocardia seriolae 961113 include the gene products of NGL2579 (GAPDH), NGL5701 (MMP), NGL4377 (OCTase), NGL4486 (ABC transporter), NGL3372 (LLE), NGL3388 (GHf10), NGL6627 (Antigen-85), NGL6696 (Esterase), and NGL6936 (CBP). These antigens were heterologously expressed in E. coli BL21 (DE3) for recombinant protein production. Then fish were vaccinated was these antigens, boosted at 2 weeks, and challenged with N. seriolae at 6 weeks after vaccination. The relative protection survival assay revealed high and significant protection efficacies of 94.45, 50.00, and 44.45 in fish that received the NGL3388 (GHf10), NGL6936 (CBP), and NGL3372 (LLE) vaccines, respectively. There were no apparent relationships or differences in tissue lesions among the administered vaccines. The serum titers against the bacterial preparations were higher for all vaccinated groups than for the control group at 4 weeks after immunization. However, no significant difference in serum titer was found at 6 weeks after immunization. The results of this study demonstrate that subunit vaccines against fish nocardiosis have differential effects, but are highly promising for nocardial prophylaxis.