Cells undergoing apoptosis are known to modulate their tissue microenvironments. By acting on phagocytes, notably macrophages, apoptotic cells inhibit immunological and inflammatory responses and promote trophic signaling pathways. Paradoxically because of their potential to cause death of tumor cells and thereby militate against malignant disease progression, both apoptosis and tumor-associated macrophages (TAM) are often associated with poor prognosis in cancer. In order to better understand the influence of tumor cell apoptosis and in particular its effect on TAM, we investigated global gene expression signatures of undisturbed TAM engaged in engulfment of apoptotic tumor cells. We studied a xenograft model of an aggressive starry-sky non-Hodgkins lymphoma, Burkitts lymphoma (BL), in which apoptotic tumor cells are common and frequently observed in association with the starry-sky TAM (SS-TAM, so called because they appear histologically as stars in a sky of tumor cells) that accumulate in these tumors. We used a BL cell line (BL2) whose cells phenotypically resemble the tumor biopsy cells from which the line was derived including the capacity to undergo apoptosis constitutively. BL xenografts in SCID mice closely recapitulated the starry-sky histological picture of the human lymphoma. Due to the high sensitivity of macrophages to their environments, we adopted laser-capture microdissection of individual SS-TAM in BL xenografts in order to obtain unbiased in situ transcriptional profiles of these cells, which we compared specifically with those of similarly-captured macrophages, the tingible-body macrophages from normal germinal centers (GCM). The rationale for this comparison was based upon BL being a germinal center malignancy and tingible-body macrophages being regarded as normal equivalents of SS-TAM.
Oncogenic properties of apoptotic tumor cells in aggressive B cell lymphoma.
Sex, Specimen part
View SamplesOBJECTIVE: Previous expression microarray analyses have failed to take into consideration the genetic heterogeneity and complex patterns of ERG gene alteration frequently found in cancerous prostates. The objective of this study is for the first time, to integrate the mapping of ERG gene alterations with the collection of expression microarray data.
Integration of ERG gene mapping and gene-expression profiling identifies distinct categories of human prostate cancer.
Sex, Specimen part
View SamplesCerebral organoids, three-dimensional cultures that model organogenesis, provide a new platform to investigate human brain development. High cost, variability and tissue heterogeneity limit accessibility and broad applications of current organoid technologies. Here we developed a miniaturized spinning bioreactor (SpinO) to generate forebrain-specific organoids from human iPSCs. These organoids recapitulate key features of human cortical development, including progenitor zone organization, neurogenesis, gene expression, and importantly, a distinct human-specific outer radial glia cell layer. We have also developed protocols to generate midbrain and hypothalamic organoids. Finally, we employed this forebrain organoid platform to model Zika virus (ZIKV) exposure. Quantitative analyses revealed that preferential, productive ZIKA infection of cortical neural progenitors leads to increased cell death and reduced proliferation, resulting in decreased neuronal cell layer volume that resembles microcephaly. Together, our brain region-specific organoids and SpinO provide an accessible and versatile platform for modeling human brain development and diseases, and for compound testing. Overall design: Time course of human cerebral organoid cultures. No Zika virus infection is involved.
Brain-Region-Specific Organoids Using Mini-bioreactors for Modeling ZIKV Exposure.
Subject, Time
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