Extended culture and imaging of normal and regenerating adult zebrafish hearts in a fluidic device.

Myocardial infarction and heart failure are leading causes of death worldwide, in large part because adult human myocardium has extremely limited regeneration capacity. Zebrafish are a powerful model for identifying new strategies for human cardiac repair because their hearts regenerate after relatively severe injuries. Zebrafish are also relatively scalable and compatible with many genetic tools.

The Tumor Microenvironment at a Turning Point Knowledge Gained Over the Last Decade, and Challenges and Opportunities Ahead: A White Paper from the NCI TME Network.

Over the past 10 years, the Tumor Microenvironment Network (TMEN), supported by the NCI (Bethesda, MD), has promoted collaborative research with the explicit goal of fostering multi-institutional and transdisciplinary groups that are capable of addressing complex issues involving the tumor microenvironment. The main goal of the TMEN was to generate novel information about the dynamic complexity of tumor-host interactions in different organ systems with emphasis on using human tissues and supplemented by experimental models. As this initiative comes to a close, members of the TMEN took time to examine what has been accomplished by the Network and importantly to identify the challenges and opportunities ahead.

Lower Preprandial Insulin and Altered Fuel Use in HIV/Antiretroviral-Exposed Infants in Cameroon.

Context: Intrauterine HIV/antiretroviral (ARV) and postnatal ARVs are known to perturb energy metabolism and could have permanent effects on future metabolic health. Such maladaptive effects could be mediated by changes in mitochondrial function and intermediary metabolism due to fetal and early-life ARV exposure in HIV/ARV-exposed uninfected (HEU) infants.

Objective: The objective of the study was to understand the relationship(s) between mitochondrial fuel use (assessed via acylcarnitines and branched chain amino acids) and preprandial insulin in infants exposed to in utero HIV/ARV plus postnatal zidovudine or nevirapine compared with HIV/ARV-unexposed uninfected (HUU) infants.

Bone marrow-derived mesenchymal stromal cells promote survival and drug resistance in tumor cells.

Bone marrow mesenchymal stromal cells (BMMSC) have antitumorigenic activities. Here, we hypothesized that circulating BMMSC are incorporated into tumors and protect tumor cells from therapy-induced apoptosis. Adherent cells harvested from murine bone marrow and expressing phenotypic and functional characteristics of BMMSC were tested for their antitumor activity against murine 4T1 mammary adenocarcinoma and LL/2 Lewis lung carcinoma cells.

Desmoplasia: a response or a niche?

Desmoplasia--the presence of a rich stroma around a tumor--has long been associated with a poor clinical outcome in patients with cancer. It is considered to be a response to the presence of invasive tumor cells. There is now evidence that desmoplasia is the result of coordinated changes in several stromal cells under the control of a single gene product, CD36, whose repression leads to a decrease in fat accumulation and an increase in matrix deposition.

Expression of cassini, a murine gamma-satellite sequence conserved in evolution, is regulated in normal and malignant hematopoietic cells.

Background: Acute lymphoblastic leukemia (ALL) cells treated with drugs can become drug-tolerant if co-cultured with protective stromal mouse embryonic fibroblasts (MEFs).

Results: We performed transcriptional profiling on these stromal fibroblasts to investigate if they were affected by the presence of drug-treated ALL cells. These mitotically inactivated MEFs showed few changes in gene expression, but a family of sequences of which transcription is significantly increased was identified.

c-Abl is an upstream regulator of acid sphingomyelinase in apoptosis induced by inhibition of integrins αvβ3 and αvβ5.

Inhibition of integrins αvβ3/αvβ5 by the cyclic function-blocking peptide, RGDfV (Arg-Gly-Asp-Phe-Val) can induce apoptosis in both normal cells and tumor cells. We show that RGDfV induced apoptosis in ECV-304 carcinoma cells, increased activity and mRNA expression of acid sphingomyelinase (ASM), and increased ceramides C(16), C(18:0), C(24:0) and C(24:1) while decreasing the corresponding sphingomyelins. siRNA to ASM decreased RGDfV-induced apoptosis as measured by TUNEL, PARP cleavage, mitochondrial depolarization, and caspase-3 and caspase-8 activities, as well as by annexinV in a 3D collagen model.

Treatment of human pre-B acute lymphoblastic leukemia with the Aurora kinase inhibitor PHA-739358 (Danusertib).

Background: Treatment of Philadelphia chromosome-positive acute lymphoblastic leukemias (Ph-positive ALL) with clinically approved inhibitors of the Bcr/Abl tyrosine kinase frequently results in the emergence of a leukemic clone carrying the T315I mutation in Bcr/Abl, which confers resistance to these drugs. PHA-739358, an Aurora kinase inhibitor, was reported to inhibit the Bcr/Abl T315I mutant in CML cells but no preclinical studies have examined this in detail in human ALL.

Results: We compared the sensitivity of human Bcr/Abl T315I, Bcr/Abl wild type and non-Bcr/Abl ALL cells to this drug.

GG: An Updated Strategy to Use Microbial Products to Promote Health.

It is now widely appreciated that probiotics exert their beneficial effects through several mechanisms, including inhibitory effects on pathogens, maintenance of the balance of intestinal microbiota, and regulation of immune responses and intestinal epithelial homeostasis. A significant area of progress has come from observations that specific products derived from probiotics mediate their mechanism(s) of action. This review focuses on new insights into the well-studied probiotic bacterium GG (LGG).

Platelet-derived growth factor receptor beta is critical for zebrafish intersegmental vessel formation.

Background: Platelet-derived growth factor receptor beta (PDGFRbeta) is a tyrosine kinase receptor known to affect vascular development. The zebrafish is an excellent model to study specific regulators of vascular development, yet the role of PDGF signaling has not been determined in early zebrafish embryos. Furthermore, vascular mural cells, in which PDGFRbeta functions cell autonomously in other systems, have not been identified in zebrafish embryos younger than 72 hours post fertilization.

Interleukin-6 in bone metastasis and cancer progression.

The bone and bone marrow are among the most frequent sites of cancer metastasis. It is estimated that 350,000 patients die with bone metastases annually in the United States. The ability of tumor cells to colonize the bone marrow and invade the bone is the result of close interactions between tumor cells and the bone marrow microenvironment.

Novel cancer vaccine based on genes of Salmonella pathogenicity island 2.

Although tumors express potentially immunogenic tumor-associated antigens (TAAs), cancer vaccines often fail because of inadequate antigen delivery and/or insufficient activation of innate immunity. Engineering nonpathogenic bacterial vectors to deliver TAAs of choice may provide an efficient way of presenting TAAs in an immunogenic form. In this study, we used genes of Salmonella pathogenicity island 2 (SPI2) to construct a novel cancer vaccine in which a TAA, survivin, was fused to SseF effector protein and placed under control of SsrB, the central regulator of SPI2 gene expression.

Valpha24-invariant NKT cells mediate antitumor activity via killing of tumor-associated macrophages.

Tumor infiltration with Valpha24-invariant NKT cells (NKTs) associates with favorable outcome in neuroblastoma and other cancers. Although NKTs can be directly cytotoxic against CD1d+ cells, the majority of human tumors are CD1d-. Therefore, the role of NKTs in cancer remains largely unknown.

Plasminogen activator inhibitor-1 protects endothelial cells from FasL-mediated apoptosis.

Plasminogen activator inhibitor-1 (PAI-1) paradoxically enhances tumor progression and angiogenesis; however, the mechanism supporting this role is not known. Here we provide evidence that PAI-1 is essential to protect endothelial cells (ECs) from FasL-mediated apoptosis. In the absence of host-derived PAI-1, human neuroblastoma cells implanted in PAI-1-deficient mice form smaller and poorly vascularized tumors containing an increased number of apoptotic ECs.

Identification of galectin-3-binding protein as a factor secreted by tumor cells that stimulates interleukin-6 expression in the bone marrow stroma.

We have previously demonstrated that neuroblastoma cells increase the expression of interleukin-6 by bone marrow stromal cells and that stimulation does not require cell-cell contact. In this study we report the purification and identification of a protein secreted by neuroblastoma cells that stimulates interleukin-6 production by stromal cells. Using a series of chromatographic purification steps including heparin-affinity, ion exchange, and molecular sieve chromatography followed by trypsin digestion and liquid chromatography tandem mass spectrometry, we identified in serum-free conditioned medium of neuroblastoma cells several secreted peptides including galectin-3-binding protein, also known as 90-kDa Mac-2-binding protein.

Development of lentiviral vectors with regulated respiratory epithelial expression in vivo.

Development of gene transfer vectors with regulated, lung-specific expression will be a useful tool for studying lung biology and developing gene therapies. In this study we constructed a series of lentiviral vectors with regulatory elements predicted to produce lung-specific transgene expression: the surfactant protein C promoter (SPC) for alveolar epithelial type II cell (AECII) expression, the Clara cell 10-kD protein (CC10) for Clara cell expression in the airway, and the Jaagskiete sheep retrovirus (JSRV) promoter for expression in both cell types. Transgene expression from the SPC and CC10 vectors was restricted to AECII and Clara cell lines, respectively, while expression from the JSRV vector was observed in multiple respiratory and nonrespiratory cell types.

Mechanisms of invasion and metastasis in human neuroblastoma.

Neuroblastoma is the second most common solid tumor in children that is metastatic in 70% of patients at the time of diagnosis. The ability of neuroblastoma cells to colonize distant organs like the bone marrow and the bone is the result of close interactions between tumor cells and the microenvironment. Significant progress has been recently made in our understanding of the mechanisms that promote the colonization and invasion of the bone by neuroblastoma cells and these mechanisms are reviewed in this article.

Multimodal imaging analysis of tumor progression and bone resorption in a murine cancer model.

Objective: This study evaluates the use of multimodal imaging to qualitatively and quantitatively measure tumor progression and bone resorption in a xenotransplanted tumor model of human neuroblastoma.

Methods: Human neuroblastoma cells expressing a luciferase reporter gene were injected into the femur of nu/nu mice. Tumor progression with and without zoledronic acid treatment was monitored using radiographs, D-luciferin-induced luminescence, micro-computer tomography (CT) and micro-magnetic resonance imaging (MRI).

A novel function for the protein tyrosine phosphatase Shp2 during lung branching morphogenesis.

Branching morphogenesis of many organs, including the embryonic lung, is a dynamic process in which growth factor mediated tyrosine kinase receptor activation is required, but must be tightly regulated to direct ramifications of the terminal branches. However, the specific regulators that modulate growth factor signaling downstream of the tyrosine kinase receptor remain to be determined. Herein, we demonstrate for the first time an important function for the intracellular protein tyrosine phosphatase Shp2 in directing embryonic lung epithelial morphogenesis.

The contribution of bone marrow-derived cells to the tumor vasculature in neuroblastoma is matrix metalloproteinase-9 dependent.

The contribution of the tumor stroma to cancer progression has been increasingly recognized. We had previously shown that in human neuroblastoma tumors orthotopically implanted in immunodeficient mice, stromal-derived matrix metalloproteinase-9 (MMP-9) contributes to the formation of a mature vasculature by promoting pericyte recruitment along endothelial cells. Here we show that MMP-9 is predominantly expressed by bone marrow-derived CD45-positive leukocytes.

Dickkopf-1 (DKK1) reveals that fibronectin is a major target of Wnt signaling in branching morphogenesis of the mouse embryonic lung.

Members of the Dickkopf (Dkk) family of secreted proteins are potent inhibitors of Wnt/beta-catenin signaling. In this study we show that Dkk1, -2, and -3 are expressed distally in the epithelium, while Kremen1, the needed co-receptor, is expressed throughout the epithelium of the developing lung. Using TOPGAL mice [DasGupta, R.

Proteases, extracellular matrix, and cancer: a workshop of the path B study section.

The role of the extracellular matrix (ECM) in the tumor microenvironment is not limited to being a barrier against tumor invasion. The ECM is a reservoir of cell binding proteins and growth factors that affect tumor cell behavior. It is also substantially modified by proteases produced by tumor cells or stroma cells.

Requirement for fibroblast growth factor 10 or fibroblast growth factor receptor 2-IIIb signaling for cecal development in mouse.

Epithelial-mesenchymal interactions are critical for the formation of gastrointestinal buds such as the cecum from the midgut, but the mechanisms regulating this process remain unclear. To investigate this problem, we have studied the temporal and spatial expression of key genes known to orchestrate branching morphogenesis. At E10.