ABSTRACTmechanism or have tumor suppressive functions, depending on the context. In addition, autophagy is involved in other important aspects of blood cancers as it promotes immune competence and anticancer immunity, and may even help to enhance patients' tolerance to standard treatments.

Scope Human breast milk has been shown to prevent necrotizing enterocolitis (NEC). Although exosomes have been identified in breast milk, their function and components have not been fully addressed. This study is conducted to elucidate the differences in peptidomic complexities between preterm and term milk exosomes. Methods and results Breast milk samples are collected from healthy lactating mothers who have delivered term and preterm infants. Exosomes are separated and quantified. The protective effects of purified exosomes against NEC are investigated both in vitro and in vivo. The peptidomic complexities in term and preterm milk exosomes are analyzed by iTRAQ LC‐MS/MS to screen differentially expressed exosomal peptides. Preterm milk exosomes administration significantly enhances proliferation and migration of intestinal epithelial cells compared with term milk exosomes. A total of 70 peptides are found to be significantly modulated in preterm milk samples compared to term milk samples. Of these, 47 peptides are upregulated, and 23 peptides are downregulated. Bioinformatics analysis suggests several potential regulatory roles of the altered peptides in intestinal epithelial cell function. Conclusion These results reveal the differences for the first time in peptidomic complexities between preterm and term milk exosomes. Milk exosome administration might be a promising prevention for NEC.

MYCN is amplified in 20% to 25% of neuroblastoma, and MYCN-amplified neuroblastoma contributes to a large percent of pediatric cancer–related deaths. Therapy improvements for this subtype of cancer are a high priority. Here we uncover a MYCN-dependent therapeutic vulnerability in neuroblastoma. Namely, amplified MYCN rewires the cell through expression of key receptors, ultimately enhancing iron influx through increased expression of the iron import transferrin receptor 1. Accumulating iron causes reactive oxygen species (ROS) production, and MYCN-amplified neuroblastomas show enhanced reliance on the system Xc- cystine/glutamate antiporter for ROS detoxification through increased transcription of this receptor. This dependence creates a marked vulnerability to targeting the system Xc-/glutathione (GSH) pathway with ferroptosis inducers. This reliance can be exploited through therapy with FDA-approved rheumatoid arthritis drugs sulfasalazine (SAS) and auranofin: in MYCN-amplified, patient-derived xenograft models, both therapies blocked growth and induced ferroptosis. SAS and auranofin activity was largely mitigated by the ferroptosis inhibitor ferrostatin-1, antioxidants like N-acetyl-L-cysteine, or by the iron scavenger deferoxamine (DFO). DFO reduced auranofin-induced ROS, further linking increased iron capture in MYCN-amplified neuroblastoma to a therapeutic vulnerability to ROS-inducing drugs. These data uncover an oncogene vulnerability to ferroptosis caused by increased iron accumulation and subsequent reliance on the system Xc-/GSH pathway. Significance: This study shows how MYCN increases intracellular iron levels and subsequent GSH pathway activity and demonstrates the antitumor activity of FDA-approved SAS and auranofin in patient-derived xenograft models of MYCN-amplified neuroblastoma.

Human embryogenesis is believed to involve an integrated set of complex yet coordinated development of different organs and tissues mediated by the changes in the spatiotemporal expression of many genes. Here, we report a genome-wide expression analysis during wk 4-9 of human embryogenesis, a critical period when most organs develop. About half of all human genes are expressed, and 18.6% of the expressed genes were significantly regulated during this important period. We further identified >5000 regulated genes, most of which previously were not known to be associated with animal development. Our study fills an important gap in mammalian developmental studies by identifying functional pathways involved in this critical but previously not studied period. Our study also revealed that the genes involved here are distinct from those during early embryogenesis, which include three groups of maternal genes. Furthermore, we discovered that genes in a given developmental process are regulated coordinately. This led us to develop an easily searchable database of this entire collection of gene expression profiles, allowing for the identification new genes important for a particular developmental process/pathway and deducing the potential function of a novel gene. The validity of the predictions from the database was demonstrated with two examples through spatiotemporal analyses of the two novel genes. Such a database should serve as a highly valuable resource for the molecular analysis of human development and pathogenesis.