Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

Harnessing the NEON data revolution to advance open environmental science with a diverse and data-capable community

It is a critical time to reflect on the National Ecological Observatory Network (NEON) science to date as well as envision what research can be done right now with NEON (and other) data and what training is needed to enable a diverse user community. NEON became fully operational in May 2019 and has pivoted from planning and construction to operation and maintenance. In this overview, the history of and foundational thinking around NEON are discussed. A framework of open science is described with a discussion of how NEON can be situated as part of a larger data constellation—across existing networks and different suites of ecological measurements and sensors. Next, a synthesis of early NEON science, based on >100 existing publications, funded proposal efforts, and emergent science at the very first NEON Science Summit (hosted by Earth Lab at the University of Colorado Boulder in October 2019) is provided. Key questions that the ecology community will address with NEON data in the next 10 yr are outlined, from understanding drivers of biodiversity across spatial and temporal scales to defining complex feedback mechanisms in human–environmental systems. Last, the essential elements needed to engage and support a diverse and inclusive NEON user community are highlighted: training resources and tools that are openly available, funding for broad community engagement initiatives, and a mechanism to share and advertise those opportunities. NEON users require both the skills to work with NEON data and the ecological or environmental science domain knowledge to understand and interpret them. This paper synthesizes early directions in the community’s use of NEON data, and opportunities for the next 10 yr of NEON operations in emergent science themes, open science best practices, education and training, and community building

Detection of Colorectal Adenomas Using a Bioactivatable Probe Specific for Matrix Metalloproteinase Activity1

A significant proportion of colorectal adenomas, in particular those that lack an elevated growth component, continue to escape detection during endoscopic surveillance. Elevation of the activity of matrix metalloproteinases (MMPs), a large family of zinc endopeptidases, in adenomas serves as a biomarker of early tumorigenesis. The goal of this study was to assess the feasibility of using a newly developed near-infrared bioactivatable probe (MMPSense 680) that reports the activity of a broad array of MMP isoforms to detect early colorectal adenomas. Adenomatous polyposis coli (Apc)+/Min-FCCC mice that spontaneously develop multiple colorectal adenomas were injected with MMPSense 680, and the colons were imaged in an IVIS Spectrum system ex vivo. Image analyses were correlated with histopathologic findings for all regions of interest (ROIs). The biochemical basis of fluorescent signal was investigated by immunohistochemical staining of MMP-7 and -9. A strong correlation (Kendall = 0.80) was observed between a positive signal and the presence of pathologically confirmed colonic adenomas; 92.9% of the 350 ROIs evaluated were classified correctly. The correlation between two independent observers was 0.87. MMP-7 expression was localized to epithelial cells of adenomas and microadenomas, whereas staining of MMP-9 was found in infiltrating polymorphonuclear leukocytes within the adenomas. MMPSense 680 identifies colorectal adenomas, both polypoid and nonpolypoid, in Apc+/Min-FCCC mice with high specificity. Use of this fluorescent probe in combination with colonoscopy could aid in preventing colorectal neoplasias by providing new opportunities for early detection and therapeutic intervention

Antisense-MDM2 Sensitizes LNCaP Prostate Cancer Cells to Androgen Deprivation, Radiation, and the Combination In Vivo

Purpose: To test the effects of antisense (AS)-MDM2 alone and with androgen deprivation (AD), radiotherapy (RT), and AD + RT on wild-type LNCaP cells in an orthotopic in vivo model. Methods: Androgen-sensitive LNCaP cells were grown in the prostates of nude mice. Magnetic resonance imaging–based tumor volume and serum prostate-specific antigen (PSA) measurements were used to assess effects on tumor response. Tumor response was measured by biochemical and tumor volume failure definitions and doubling time estimates from fitted PSA and tumor volume growth curves. Expression of MDM2, p53, p21, and Ki-67 was quantified using immunohistochemical staining and image analysis of formalin-fixed tissue, analogous to methods used clinically. Results: Antisense-MDM2 significantly inhibited the growth of LNCaP tumors over the mismatch controls. The most significant increase in tumor growth delay and tumor doubling time was from AS-MDM2 + AD + RT, although the effect of AS-MDM2 + AD was substantial. Expression of MDM2 was significantly reduced by AS-MDM2 in the setting of RT. Conclusions: This is the first in vivo investigation of the effects of AS-MDM2 in an orthotopic model and the first to demonstrate incremental sensitization when added to AD and AD + RT. The results with AD underscore the potential to affect micrometastatic disease, which is probably responsible for treatment failure in 30–40% of men with high-risk disease

Combined In Vivo Molecular and Anatomic Imaging for Detection of Ovarian Carcinoma-Associated Protease Activity and Integrin Expression in Mice

Most patients with epithelial ovarian cancer (EOC) experience drug-resistant disease recurrence. Identification of new treatments is a high priority, and preclinical studies in mouse models of EOC may expedite this goal. We previously developed methods for magnetic resonance imaging (MRI) for tumor detection and quantification in a transgenic mouse model of EOC. The goal of this study was to determine whether three-dimensional (3D) fluorescence molecular tomography (FMT) and fluorescent molecular imaging probes could be effectively used for in vivo detection of ovarian tumors and response to therapy. Ovarian tumor-bearing TgMISIIR-TAg mice injected with fluorescent probes were subjected to MRI and FMT. Tumor-specific probe retention was identified in vivo by alignment of the 3D data sets, confirmed by ex vivo fluorescent imaging and correlated with histopathologic findings. Mice were treated with standard chemotherapy, and changes in fluorescent probe binding were detected by MRI and FMT. Ovarian tumors were detected using probes specific for cathepsin proteases, matrix metalloproteinases (MMPs), and integrin αvβ3. Cathepsin and integrin αvβ3 probe activation and retention correlated strongly with tumor volume. MMP probe activation was readily detected in tumors but correlated less strongly with tumor volume. Tumor regression associated with response to therapy was detected and quantified by serial MRI and FMT. These results demonstrate the feasibility and sensitivity of FMT for detection and quantification of tumor-associated biologic targets in ovarian tumors and support the translational utility of molecular imaging to assess functional response to therapy in mouse models of EOC

PKA Knockdown Enhances Cell Killing In Response To Radiation And Androgen Deprivation

The therapeutic efficacy of Gem®231, a second generation antisense molecule targeted to the RIα subunit of PKA RIα (AS-PKA), administered in combination with androgen deprivation (AD) and radiation therapy (RT), was examined in androgen sensitive (LNCaP) and insensitive (PC3) cell lines. Apoptosis was assayed by Caspase 3+7 activity and AnnexinV binding. AS-PKA significantly increased apoptosis in vitro from RT (both lines), with further increases in LNCaP cells grown in AD medium. In LNCaP cells, AD increased phosphorylated map-kinase (pMAPK), which was reduced by AS-PKA relative to the MM controls. AS-PKA also reduced pMAPK levels in PC3 cells. Cell death was measured by clonogenic survival assays. In vivo , LNCaP cells were grown orthotopically in nude mice. Tumor kinetics were measured by magnetic resonance imaging and serum prostate-specific antigen. PC3 cells were grown subcutaneously and tumor volume assessed by caliper measurements. In PC3 xenografts, AS-PKA caused a significant increase in tumor doubling time relative to MM controls as a monotherapy or in combination with RT. In orthotopic LNCaP tumors, AS-PKA was ineffective as a monotherapy; however it caused a statistically significant increase in tumor doubling time relative to MM controls when used in combination with AD, with or without RT. PKA RIα levels in tumors were quantified via immunohistochemical (IHC) staining and image analysis. IHC measurements in LNCaP cells showed that AS-PKA reduced PKA RIα levels in vivo . We demonstrate for the first time that AS-PKA enhances cell killing androgen sensitive prostate cancer cells to AD±RT and androgen insensitive cells to RT

Opposing effects of inhibitors of Aurora-A and EGFR in Autosomal Dominant Polycystic Kidney Disease (ADPKD)

Aurora-A kinase (AURKA) overexpression in numerous tumors induces aneuploidy, in part because of cytokinetic defects. Alisertib and other small-molecule inhibitors targeting AURKA are effective in some patients as monotherapies or combination therapies. EGFR pro-proliferative signaling activity is commonly elevated in cancer, and the EGFR inhibitor erlotinib is commonly used as a standard of care agent for cancer. An erlotinib/alisertib combination therapy is currently under assessment in clinical trials, following pre-clinical studies that indicated synergy of these drugs in cancer. We were interested in further exploring the activity of this drug combination. Beyond well-established functions for AURKA in mitotic progression, additional non-mitotic AURKA functions include control of ciliary stability and calcium signaling. Interestingly, alisertib exacerbates the disease phenotype in mouse models for autosomal dominant polycystic kidney disease (ADPKD), a common inherited syndrome induced by aberrant signaling from PKD1 and PKD2, cilia-localized proteins that have calcium channel activity. EGFR is also more active in ADPKD, making erlotinib also of potential interest in this disease setting. In this study, we have explored the interaction of alisertib and erlotinib in an ADPKD model. These experiments indicated erlotinib restrained cystogenesis, opposing alisertib action. Erlotinib also interacted with alisertib to regulate proliferative signaling proteins, albeit in a complicated manner. Results suggest a nuanced role of AURKA signaling in different pathogenic conditions and inform the clinical use of AURKA inhibitors in cancer patients with comorbidities

Inhibiting Heat Shock Protein 90 (HSP90) Limits the Formation of Liver Cysts Induced by Conditional Deletion of Pkd1 in Mice

Polycystic liver disease (PLD) occurs in 75-90% of patients affected by autosomal dominant polycystic kidney disease (ADPKD), which affects 1: 400-1,000 adults and arises from inherited mutations in the PKD1 or PKD2 genes. PLD can lead to bile duct obstructions, infected or bleeding cysts, and hepatomegaly, which can diminish quality of life. At present, no effective, approved therapy exists for ADPKD or PLD. We recently showed that inhibition of the molecular chaperone heat shock protein 90 (HSP90) with a small molecule inhibitor, STA-2842, induced the degradation of multiple HSP90-dependent client proteins that contribute to ADPKD pathogenesis and slowed the progression of renal cystogenesis in mice with conditional deletion of Pkd1. Here, we analyzed the effects of STA-2842 on liver size and cystic burden in Pkd(-/-) mice with established PLD. Using magnetic resonance imaging over time, we demonstrate that ten weeks of STA-2842 treatment significantly reduced both liver mass and cystic index suggesting selective elimination of cystic tissue. Pre-treatment cystic epithelia contain abundant HSP90; the degree of reduction in cysts was accompanied by inhibition of proliferation-associated signaling proteins EGFR and others, and induced cleavage of caspase 8 and PARP1, and correlated with degree of HSP90 inhibition and with inactivation of ERK1/2. Our results suggest that HSP90 inhibition is worth further evaluation as a therapeutic approach for patients with PLD

MMP-13 In-Vivo Molecular Imaging Reveals Early Expression in Lung Adenocarcinoma

International audienceSeveral matrix metalloproteinases (MMPs) are overexpressed in lung cancer and may serve as potential targets for the development of bioactivable probes for molecular imaging