Generation and Characterization of Novel Local and Metastatic Human Neuroblastoma Variants12

Neuroblastoma (NB) is the most commonly occurring solid tumor in children. The disease usually arises in the adrenal medulla, and it is characterized by a remarkable heterogeneity in its progression. Most NB patients with an advanced disease have massive bone marrow infiltration at diagnosis. Lung metastasis represents a widely disseminated stage and is typically considered to be a terminal event. Much like other malignancies, NB progression is a complex, multistep process. The expression, function, and significance of the various factors involved in NB progression must be studied in relevant in vivo and in vitro models. Currently, models consisting of metastatic and nonmetastatic cell variants of the same genetic background exist for several types of cancer; however, none exists for NB. In the present study, we describe the generation of a NB metastasis model. SH-SY5Y and MHH-NB-11 NB cells were inoculated orthotopically into the adrenal glands of athymic nude mice. Neuroblastoma cells metastasizing to the lungs were isolated from mice bearing adrenal tumors. Lung metastatic variants were generated by repeated cycles of in vivo passage. Characterization of these variants included cellular morphology and immunophenotyping in vitro, aggressiveness in vivo, and various biologic parameters in vitro. The NB metastatic variant in each model displayed unique properties, and both metastatic variants demonstrated a metastatic phenotype in vivo. These reproducible models of human NB metastasis will serve as an unlimited source of transcriptomic and proteomic material. Such models can facilitate future studies on NB metastasis and the identification of novel NB biomarkers and targets for therapy

The Metastatic Microenvironment: Melanoma-Microglia Cross-Talk Promotes the Malignant Phenotype of Melanoma Cells.

Melanoma has the highest propensity to metastasize to the brain compared to other cancers, as brain metastases are found frequently high in patients who have prolonged survival with visceral metastasis. Once disseminated in the brain, melanoma cells communicate with brain resident cells that include astrocytes and microglia. Microglia cells are the resident macrophages of the brain, and are the main immunological cells in the CNS involved in neuroinflammation. Data on the interactions between brain metastatic melanoma cells and microglia and on the role of microglia-mediated neuroinflammation in facilitating melanoma brain metastasis is lacking. To elucidate the role of microglia in melanoma brain metastasis progression, we examined the bidirectional interactions between microglia and melanoma cells in the tumor microenvironment. We identified the molecular and functional modifications occurring in brain-metastasizing melanoma cells and microglia cells following the treatment of each cell type with supernatants of the counter cell type. Both cells induced alteration in gene expression programs, cell signaling and cytokine secretion in the counter cell type. Moreover, melanoma cells exerted significant morphological changes on microglia cells, enhanced proliferation, induced matrix metalloproteinase-2 (MMP-2) activation and cell migration. Microglia cells induced phenotypic changes in melanoma cells increasing their malignant phenotype: increased melanoma proliferation, MMP-2 activity, cell migration, brain endothelial penetration, and tumor cells ability to grow as spheroids in 3D cultures. Our work provides a novel insight into the bi-directional interactions between melanoma and micoglia cells, suggesting the contribution of microglia to melanoma brain metastasis formation. This article is protected by copyright. All rights reserved

Lung-Residing Metastatic and Dormant Neuroblastoma Cells

The mechanism by which dormant tumor cells can begin growing after long periods of inactivity and accelerate disease recurrence is poorly understood. The present study characterizes dormant neuroblastoma (NB) cells, as well as metastatic cells, which reside in the same organ microenvironment. A xenograft model of human NB consisting of variants that generate nonmetastatic local tumors in the orthotopic inoculation site and variants that generate lung metastatic NB (MetNB) cells was developed in our laboratory. The present study shows that lungs of mice inoculated with nonmetastatic NB variants contain disseminated neuroblastoma (DisNB) human cells. Both DisNB and MetNB variants expressed a similar tumorigenicty phenotype in vivo, whereas the MetNB variants produced a heavy metastatic load and the DisNB variants produced no or little metastasis. A comparative in vitro characterization of MetNB and DisNB cells revealed similarities and differences. DisNB, but not MetNB cells, expressed the minimal residual disease markers PHOX2B and TH. MetNB cells demonstrated higher migratory capacity, an elevated matrix metalloproteinase (MMP) secretion, and a higher constitutive phosphorylation of extracellular signal-regulated kinase (ERK) than DisNB cells. We suggest that characteristics common to both MetNB and DisNB cells were acquired relatively early in the metastatic process and the characteristics that differ between these variants were acquired later. We hypothesize that the DisNB cells are metastasis precursors, which may progress toward metastasis under certain microenvironmental conditions

Perceived Impact of a Land and Property Rights Program on Violence Against Women in Rural Kenya

The current study focuses on a community-led land and property rights program in two rural provinces in western Kenya. The program was designed to respond to women's property rights violations to reduce violence against women and HIV risks at the community level. Through in-depth interviews with 30 women, we examine the perceived impact that this community-level property rights program had on violence against women at the individual and community level. We also examine perceptions as to how reductions in violence were achieved. Finally, we consider how our findings may aid researchers in the design of structural violence-prevention strategies