RRx-001, an epigenetic-based radio- and chemosensitizer, has vascular normalizing effects on SCCVII and U87 tumors.

BackgroundThe tumor-specific microregional effects of the anticancer agent RRx-001, a novel epigenetic-based radio/chemosensitizer with nitrogen oxide-donating properties in phase II clinical trials, were investigated with whole tissue section quantitative immunohistological staining in mouse SCCVII and human U87 tumors.ResultsSCCVII tumors exhibited regions of intermittent perfusion exemplified by co-localization of vessels with the hypoxia marker pimonidazole commonly occurring throughout the tissue. A moderate increase in perfusion (21 to 28 %) was observed after a bolus dose of the perivascular stain DiOC7(3), however, with the absence of an increase in tissue oxygenation. U87 tumors showed an absence of blood flow over large areas of treated tumors after dosing with RRx-001. However, these areas did not become necrotic and returned to near normal levels after 12 h. No significant change in tumor hypoxia was seen at 90 min or 12 h. For both tumor types, RRx-001 treatment resulted in the loss of perfusion in the large regions of the tumor; however, at the 12-h time point, both tumor types showed an increase in vessel perfusion but no significant decrease in hypoxia.ConclusionsThese data suggest a redistribution of blood flow within the tumor for both tumor types akin to vascular normalization. Differences between the tumors were related to tumor architecture and distribution of alpha-smooth muscle actin (α-SMA). RRx-001 shows promise for short-term blood flow redistribution in tumors with a pericyte- and α-SMA-rich vasculature. Expression of α-SMA in tumor vasculature could therefore be useful for predicting tumor response to RRx-001

Vascularization predicts overall survival and risk of transformation in follicular lymphoma

STP-53912) and by the Fundacao para a Ciencia e Tecnologia (FCT BD13230/2003), Portugal.Follicular lymphoma patients display heterogeneous overall survival and variable risk of transformation. Recent studies have highlighted the role of the microenvironment. The contribution of microvessel density to follicular lymphoma survival remains controversial. We used a quantitative tumor mapping approach to determine whether the degree of vascularization correlated with outcome in a uniformly treated cohort. Whole-tissue sections of diagnostic biopsies from 84 cases were stained for CD34 and tumor-to-vessel-distance that encompassed 90% of the tumor (TVD90) was determined using image analysis. Twenty-one cases with lower TVD90 showed inferior overall survival (P=0.0001) and high risk of transformation (P=0.01). These cases significantly correlated with increased Lymphoma-Associated Macrophages (x(2)=0.025). In multivariate analysis macrophages content, IPI and TVD90 were independent predictors of overall survival (P=0.05, P=0.001 and P=0.01, respectively) and IPI and TVD90 predicted risk of transformation (P=0.008 and P=0.08, respectively). Increased angiogenesis is an independent marker of inferior survival and may promote transformation.publishersversionpublishe

SHIP Represses the Generation of Alternatively Activated Macrophages

SummaryWe recently reported that SHIP restrains LPS-induced classical (M1) activation of in vitro differentiated, bone marrow-derived macrophages (BMMΦs) and that SHIP upregulation is essential for endotoxin tolerance. Herein, we show that in vivo differentiated SHIP−/− peritoneal (PMΦs) and alveolar (AMΦs) macrophages, unlike their wild-type counterparts, are profoundly M2 skewed (alternatively activated), possessing constitutively high arginase I (ArgI) and Ym1 levels and impaired LPS-induced NO production. Consistent with this, SHIP−/− mice display M2-mediated lung pathology and enhanced tumor implant growth. Interestingly, BMMΦs from SHIP−/− mice do not display this M2 phenotype unless exposed to TGFβ within normal mouse plasma (MP) during in vitro differentiation. Our results suggest that SHIP functions in vivo to repress M2 skewing and that macrophage polarization can occur during differentiation in response to TGFβ if progenitors have elevated PIP3

Notch Initiates the Endothelial-to-Mesenchymal Transition in the Atrioventricular Canal through Autocrine Activation of Soluble Guanylyl Cyclase

SummaryThe heart is the most common site of congenital defects, and valvuloseptal defects are the most common of the cardiac anomalies seen in the newborn. The process of endothelial-to-mesenchymal transition (EndMT) in the cardiac cushions is a required step during early valve development, and Notch signaling is required for this process. Here we show that Notch activation induces the transcription of both subunits of the soluble guanylyl cyclase (sGC) heterodimer, GUCY1A3 and GUCY1B3, which form the nitric oxide receptor. In parallel, Notch also promotes nitric oxide (NO) production by inducing Activin A, thereby activating a PI3-kinase/Akt pathway to phosphorylate eNOS. We thus show that the activation of sGC by NO through a Notch-dependent autocrine loop is necessary to drive early EndMT in the developing atrioventricular canal (AVC)

The combination of gefitinib and RAD001 inhibits growth of HER2 overexpressing breast cancer cells and tumors irrespective of trastuzumab sensitivity

<p>Abstract</p> <p>Background</p> <p>HER2-positive breast cancers exhibit high rates of innate and acquired resistance to trastuzumab (TZ), a HER2-directed antibody used as a first line treatment for this disease. TZ resistance may in part be mediated by frequent co-expression of EGFR and by sustained activation of the mammalian target of rapamycin (mTOR) pathway. Here, we assessed feasibility of combining the EGFR inhibitor gefitinib and the mTOR inhibitor everolimus (RAD001) for treating HER2 overexpressing breast cancers with different sensitivity to TZ.</p> <p>Methods</p> <p>The gefitinib and RAD001 combination was broadly evaluated in TZ sensitive (SKBR3 and MCF7-HER2) and TZ resistant (JIMT-1) breast cancer models. The effects on cell growth were measured in cell based assays using the fixed molar ratio design and the median effect principle. <it>In vivo </it>studies were performed in Rag2M mice bearing established tumors. Analysis of cell cycle, changes in targeted signaling pathways and tumor characteristics were conducted to assess gefitinib and RAD001 interactions.</p> <p>Results</p> <p>The gefitinib and RAD001 combination inhibited cell growth <it>in vitro </it>in a synergistic fashion as defined by the Chou and Talalay median effect principle and increased tumor xenograft growth delay. The improvement in therapeutic efficacy by the combination was associated <it>in vitro </it>with cell line dependent increases in cytotoxicity and cytostasis while treatment <it>in vivo </it>promoted cytostasis. The most striking and consistent therapeutic effect of the combination was increased inhibition of the mTOR pathway (<it>in vitro </it>and <it>in vivo</it>) and EGFR signaling <it>in vivo </it>relative to the single drugs.</p> <p>Conclusions</p> <p>The gefitinib and RAD001 combination provides effective control over growth of HER2 overexpressing cells and tumors irrespective of the TZ sensitivity status.</p

A Systems Approach for Tumor Pharmacokinetics

Recent advances in genome inspired target discovery, small molecule screens, development of biological and nanotechnology have led to the introduction of a myriad of new differently sized agents into the clinic. The differences in small and large molecule delivery are becoming increasingly important in combination therapies as well as the use of drugs that modify the physiology of tumors such as anti-angiogenic treatment. The complexity of targeting has led to the development of mathematical models to facilitate understanding, but unfortunately, these studies are often only applicable to a particular molecule, making pharmacokinetic comparisons difficult. Here we develop and describe a framework for categorizing primary pharmacokinetics of drugs in tumors. For modeling purposes, we define drugs not by their mechanism of action but rather their rate-limiting step of delivery. Our simulations account for variations in perfusion, vascularization, interstitial transport, and non-linear local binding and metabolism. Based on a comparison of the fundamental rates determining uptake, drugs were classified into four categories depending on whether uptake is limited by blood flow, extravasation, interstitial diffusion, or local binding and metabolism. Simulations comparing small molecule versus macromolecular drugs show a sharp difference in distribution, which has implications for multi-drug therapies. The tissue-level distribution differs widely in tumors for small molecules versus macromolecular biologic drugs, and this should be considered in the design of agents and treatments. An example using antibodies in mouse xenografts illustrates the different in vivo behavior. This type of transport analysis can be used to aid in model development, experimental data analysis, and imaging and therapeutic agent design.National Institutes of Health (U.S.) (grant T32 CA079443

Differences in architecture between native and non-indigenous macroalgae influence associations with epifauna

Non-indigenous invaders may play ecologically similar roles to native species, and this may be reflected in the abundance, richness and composition of associated species assemblages. We investigated whether associations of epifauna with their macroalgal hosts differed between the non-indigenous Codium fragile ssp. fragile and native, congeneric C. fragile on three rocky shores in southeast Australia. Of the 38 taxa we recorded, 13 were unique to the native Codium and four to non-indigenous individuals. Holdfasts of non-indigenous Codium had double the taxon richness of epifauna compared to native holdfasts, and epifaunal abundances showed a similar but non-significant difference. Patterns of abundance and richness of epifaunal taxa on thalli of native and non-indigenous Codium varied depending on whether these measures were expressed per individual alga, thallus area or number of branches. The composition of epifaunal assemblages between native and non-indigenous Codium were significantly different, but differences among rocky shores were as great as those between macroalgal species. On all shores, two taxa, the gastropod Alaba opiniosa and gammarid amphipods, contributed most to compositional differences between native and non-indigenous Codium, and their abundances were influenced by branch number and associated epiphyte load. Host choice experiments manipulating the complexity and subspecies of Codium revealed that amphipods were more strongly influenced by branch number adjusted for epiphyte load than the identity of Codium. Our results highlight the importance of habitat features, such as structural complexity and associated epiphyte load, in determining whether native and non-indigenous species provide functionally equivalent habitats for associated assemblages

Bait type affects fish assemblages and feeding guilds observed at baited remote underwater video stations

Baited remote underwater video stations (BRUVS) are increasingly being used to examine assemblages of fishes, yet critical methodological questions related to sampling limitations and bias, such as the influence of bait type, remain poorly understood. At multiple locations, we examined the hypothesis that diversity and abundance in temperate reef fish assemblages were independent of bait type. We used 3 bait types (abalone viscera, pilchards and crushed urchin) and quantified commonly used metrics for the fish assemblage, including species richness, time of first arrival and relative abundance on 3 shallow rocky reefs in southeastern Australia over 2 yr. We distinguished the following 6 feeding guilds: herbivore, zooplanktivore, alga/invertebrate consumers, invertebrate carnivore, macroinvertebrate carnivore and generalist carnivore. The response of fishes was dependent on bait type, with urchin bait performing particularly poorly. Although we did not detect statistical differences between the performance of pilchards and abalone viscera as bait, pilchards produced more consistent outcomes. Importantly, we also observed strong spatial effects. In general, bait type had a marked effect on species richness, but little influence on relative abundance. Overall we conclude that oily bait such as pilchards, which have been widely used in most studies, yield the most consistent outcomes. Consequently, bait type and spatial variation in fish assemblages needs to be considered in sampling designs to assess the limitations of BRUVS

Response of marine invertebrate larvae to natural and anthropogenic sound: a pilot study

Many vertebrates and invertebrates in the marine environment create and respond to sound. Due to increasing use of waterways, levels of anthropogenic sound are greater than ever. We examined the responses of larvae of temperate invertebrates to three sound treatments: natural ambient sound (shallow rocky reef), anthropogenic sound (an outboard motor) and no sound (control). Sound recordings were played to molluscan, echinoderm and bryozoan larvae in Petri dishes in the laboratory and the movement of swimming larvae was filmed and quantified in two-dimensional space. Larvae of the gastropod Bembicium nanum increased their swimming activity in response to both natural and anthropogenic sound, while larvae of the bryozoan Bugula neritina decreased swimming activity when exposed to boat sounds, but not recordings from the natural reef. Considerable variation was observed in the swimming behavior of larvae of the echinoid Heliocidaris erythrogramma and we did not observe any differences in response among the treatments. The behavior of the oyster Crassostrea gigas was dependent on its nutritional status. Unfed larvae did not respond to sound, whereas fed larvae increased swimming activity, but only in response to natural sound. Hence effects were highly species-specific, with three of the four species showing some response to sound and apparently distinguishing among different sound frequencies. This study adds to the growing body of evidence that sound may be an important behavioral cue. It may justify further research into the use of sound as an antifouling agent or a tool in the restoration of reef species