Dendritic cell-based cancer immunotherapy requires tumour antigens to be delivered efficiently into dendritic cells and their migration to be monitored in vivo. Nanoparticles have been explored as carriers for antigen delivery, but applications have been limited by the toxicity of the solvents used to make nanoparticles, and by the need to use transfection agents to deliver nanoparticles into cells. Here we show that an iron oxide-zinc oxide core-shell nanoparticle can deliver carcinoembryonic antigen into dendritic cells while simultaneously acting as an imaging agent. The nanoparticle-antigen complex is efficiently taken up by dendritic cells within one hour and can be detected in vitro by confocal microscopy and in vivo by magnetic resonance imaging. Mice immunized with dendritic cells containing the nanoparticle-antigen complex showed enhanced tumour antigen specific T-cell responses, delayed tumour growth and better survival than controls.

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BackgroundAging is a fundamental biological process. Characterization of genetic and environmental factors that influence lifespan is a crucial step toward understanding the mechanisms of aging at the organism level. To capture the different effects of genetic and environmental factors on lifespan, appropriate statistical analyses are needed.Methodology/Principal FindingsWe developed an online application for survival analysis (OASIS) that helps conduct various novel statistical tasks involved in analyzing survival data in a user-friendly manner. OASIS provides standard survival analysis results including Kaplan-Meier estimates and mean/median survival time by taking censored survival data. OASIS also provides various statistical tests including comparison of mean survival time, overall survival curve, and survival rate at specific time point. To visualize survival data, OASIS generates survival and log cumulative hazard plots that enable researchers to easily interpret their experimental results. Furthermore, we provide statistical methods that can analyze variances among survival datasets. In addition, users can analyze proportional effects of risk factors on survival.Conclusions/SignificanceOASIS provides a platform that is essential to facilitate efficient statistical analyses of survival data in the field of aging research. Web application and a detailed description of algorithms are accessible from http://sbi.postech.ac.kr/oasis.

Mild inhibition of mitochondrial respiration extends the lifespan of many species. In Caenorhabditis elegans, reactive oxygen species (ROS) promote longevity by activating hypoxia-inducible factor 1 (HIF-1) in response to reduced mitochondrial respiration. However, the physiological role and mechanism of ROS-induced longevity are poorly understood. Here, we show that a modest increase in ROS increases the immunity and lifespan of C. elegans through feedback regulation by HIF-1 and AMP-activated protein kinase (AMPK). We found that activation of AMPK as well as HIF-1 mediates the longevity response to ROS. We further showed that AMPK reduces internal levels of ROS, whereas HIF-1 amplifies the levels of internal ROS under conditions that increase ROS. Moreover, mitochondrial ROS increase resistance to various pathogenic bacteria, suggesting a possible association between immunity and long lifespan. Thus, AMPK and HIF-1 may control immunity and longevity tightly by acting as feedback regulators of ROS.aging | mitochondria | immunity | reactive oxygen species | C. elegans M itochondria are essential for various physiological processes, including energy production, apoptosis, metabolism, and signaling (1). Thus, it is not surprising that defects in mitochondrial function are linked to many diseases. Interestingly, however, mild inhibition of mitochondrial respiration increases the lifespans of many organisms (2, 3). In particular, genetic inhibition of components of the mitochondrial electron transport chain (ETC) increases longevity of the roundworm Caenorhabditis elegans. For example, mutations in clk-1 (a ubiquinone hydroxylase) and isp-1 (iron-sulfur protein 1 in the mitochondrial complex III) extend the lifespans of worms (4, 5). Longevity resulting from mitochondrial ETC inhibition also has been observed in Drosophila (6, 7) and mice (8, 9). Thus, the mechanisms responsible for longevity may be evolutionarily conserved.Key genetic factors that mediate longevity caused by reduced mitochondrial respiration in C. elegans have been identified recently (10-17). However, the mechanisms are not completely understood. Hypoxia-inducible factor 1 (HIF-1), the master transcriptional regulator of cellular responses to hypoxia, is one of the mediators of longevity caused by inhibition of mitochondrial respiration in C. elegans (12). The physiological importance of HIF-1α in humans is underscored by the fact that mutations in VHL, the von HippelLindau tumor suppressor gene, which encodes an E3-ubiquitin ligase component required for the degradation of HIF-1, lead to an inherited form of cancer (18,19). HIF-1 regulates adaptation to low oxygen and various other biological processes, including axon guidance, immunity, iron homeostasis, and aging (20-29). Increased levels of HIF-1 by vhl-1 mutations or by overexpression of HIF-1 lengthen the lifespan of C. elegans (27, 28). In addition, we previously showed that inhibition of mitochondrial respiration promotes longevity by elevating reactive oxygen species (ROS) levels and incr...

Various mammalian cells including tumor cells secrete extracellular vesicles (EVs), otherwise known as exosomes and microvesicles. EVs are nanosized bilayered proteolipids and play multiple roles in intercellular communication. Although many vesicular proteins have been identified, their functional interrelationships and the mechanisms of EV biogenesis remain unknown. By interrogating proteomic data using systems approaches, we have created a protein interaction network of human colorectal cancer cell-derived EVs which comprises 1491 interactions between 957 vesicular proteins. We discovered that EVs have well-connected clusters with several hub proteins similar to other subcellular networks. We also experimentally validated that direct protein interactions between cellular proteins may be involved in protein sorting during EV formation. Moreover, physically and functionally interconnected protein complexes form functional modules involved in EV biogenesis and functions. Specifically, we discovered that SRC signaling plays a major role in EV biogenesis, and confirmed that inhibition of SRC kinase decreased the intracellular biogenesis and cell surface release of EVs. Our study provides global insights into the cargo-sorting, biogenesis, and pathophysiological roles of these complex extracellular organelles.