Cecal Metastasis of Clear Cell Renal Cell Carcinoma After Previous Nephrectomy.

Metastasis of renal cell carcinoma (RCC) to the gastrointestinal (GI) tract is exceedingly rare. We present a case of a man in his 40s with a history of RCC that had metastasized to his abdominal wall and brain who then presented with abdominal pain and melena. On presentation, imaging showed new bone metastases and a colonic mass in the ascending colon. The biopsy of the mass from colonoscopy demonstrated RCC primary. Although rare, this case report highlights the importance of a thorough evaluation of patients with a history of RCC and considers GI tract involvement in those presenting with GI bleeding.

Selective In Vitro and Ex Vivo Staining of Brain Neurofibrillary Tangles and Amyloid Plaques by Novel Ethylene Ethynylene-Based Optical Sensors.

The identification of protein aggregates as biomarkers for neurodegeneration is an area of interest for disease diagnosis and treatment development. In this work, we present novel super luminescent conjugated polyelectrolyte molecules as ex vivo sensors for tau-paired helical filaments (PHFs) and amyloid-ß (Aß) plaques. We evaluated the use of two oligo-p-phenylene ethynylenes (OPEs), anionic OPE12- and cationic OPE24+, as stains for fibrillar protein pathology in brain sections of transgenic mouse (rTg4510) and rat (TgF344-AD) models of Alzheimer's disease (AD) tauopathy, and post-mortem brain sections from human frontotemporal dementia (FTD). OPE12- displayed selectivity for PHFs in fluorimetry assays and strong staining of neurofibrillary tangles (NFTs) in mouse and human brain tissue sections, while OPE24+ stained both NFTs and Aß plaques. Both OPEs stained the brain sections with limited background or non-specific staining. This novel family of sensors outperformed the gold-standard dye Thioflavin T in sensing capacities and co-stained with conventional phosphorylated tau (AT180) and Aß (4G8) antibodies. As the OPEs readily bind protein amyloids in vitro and ex vivo, they are selective and rapid tools for identifying proteopathic inclusions relevant to AD. Such OPEs can be useful in understanding pathogenesis and in creating in vivo diagnostically relevant detection tools for neurodegenerative diseases.

Partial CHARGE syndrome with bilateral retinochoroidal colobomas associated with 7q11.23 duplication syndrome: case report.

BACKGROUND: CHARGE syndrome is a relatively common cause of deafness and blindness resulting from failure to form the primordia of specific organs due to deficient contribution of neural crest cell derivatives. The majority of CHARGE syndrome cases are caused by heterozygous mutations in CHD7 on chromosome 8q21. Those with CHARGE syndrome without CHD7 mutation typically do not have an identified genetic defect. 7q11.23 duplication syndrome is associated with mild facial dysmorphism, heart defects, language delay, and autism spectrum disorder. In the current literature, 7q11.23 duplication has not been associated with CHARGE syndrome, retinochoroidal colobomas, or significant ear abnormalities. CASE PRESENTATION: We describe a patient with 7q11.23 duplication syndrome and clinical CHARGE syndrome with no variant in CHARGE-associated genes. CONCLUSIONS: This case highlights the still incomplete understanding of the pathogenesis of CHARGE syndrome and raises the possibility of a dose-sensitive effect of genes in the 7q11.23 critical region on neural crest differentiation and fate.

Highly Effective Inactivation of SARS-CoV-2 by Conjugated Polymers and Oligomers.

In the present study, we examined the inactivation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by synthetic conjugated polymers and oligomers developed in our laboratories as antimicrobials for bacteria, fungi, and nonenveloped viruses. The results show highly effective light-induced inactivation with several of these oligomers and polymers including irradiation with near-UV and visible light. In the best case, one oligomer induced a 5-log reduction in pfu/mL within 10 min. In general, the oligomers are more active than the polymers; however, the polymers are active with longer wavelength visible irradiation. Although not studied quantitatively, the results show that in the presence of the agents at concentrations similar to those used in the light studies, there is essentially no dark inactivation of the virus. Because three of the five materials/compounds examined are quaternary ammonium derivatives, this study indicates that conventional quaternary ammonium antimicrobials may not be active against SARS-CoV-2. Our results suggest several applications involving the incorporation of these materials in wipes, sprays, masks, and clothing and other personal protection equipment that can be useful in preventing infections and the spreading of this deadly virus and future outbreaks from similar viruses.

Highly Effective Inactivation of SARS-CoV-2 by Conjugated Polymers and Oligomers.

The current Covid-19 Pandemic caused by the highly contagious SARS-CoV-2 virus has proven extremely difficult to prevent or control. Currently there are few treatment options and very few long-lasting disinfectants available to prevent the spread. While masks and protective clothing and social distancing may offer some protection, their use has not always halted or slowed the spread. Several vaccines are currently undergoing testing; however there is still a critical need to provide new methods for inactivating the virus before it can spread and infect humans. In the present study we examined the inactivation of SARS-CoV-2 by synthetic conjugated polymers and oligomers developed in our laboratories as antimicrobials for bacteria, fungi and non-enveloped viruses. Our results show that we can obtain highly effective light induced inactivation with several of these oligomers and polymers including irradiation with near-UV and visible light. With both the oligomers and polymers, we can reach several logs of inactivation with relatively short irradiation times. Our results suggest several applications involving the incorporation of these materials in wipes, sprays, masks and clothing and other Personal Protection Equipment (PPE) that can be useful in preventing infections and the spreading of this deadly virus and future outbreaks from similar viruses.

HDO production from [2H7]glucose Quantitatively Identifies Warburg Metabolism.

Increased glucose uptake and aerobic glycolysis are striking features of many cancers. These features have led to many techniques for screening and diagnosis, but many are expensive, less feasible or have harmful side-effects. Here, we report a sensitive 1H/2H NMR method to measure the kinetics of lactate isotopomer and HDO production using a deuterated tracer. To test this hypothesis, HUH-7 hepatocellular carcinoma and AML12 normal hepatocytes were incubated with [2H7]glucose. 1H/2H NMR data were recorded for cell media as a function of incubation time. The efflux rate of lactate-CH3, lactate-CH2D and lactate-CHD2 was calculated as 0.0033, 0.0071, and 0.0.012 µmol/106cells/min respectively. Differential production of lactate isotopomers was due to deuterium loss during glycolysis. Glucose uptake and HDO production by HUH-7 cells showed a strong correlation, indicating that monitoring the HDO production could be a diagnostic feature in cancers. Deuterium mass balance of [2H7]glucose uptake to 2H-lactate and HDO production is quantitatively matched, suggesting increasing HDO signal could be used to diagnose Warburg (cancer) metabolism. Measuring the kinetics of lactate isotopomer and HDO production by 1H and 2H MR respectively are highly sensitive. Increased T1 of 2H-lactate isotopomers indicates inversion/saturation recovery methods may be a simple means of generating metabolism-based contrast.

Gain-of-Function Mutant p53 R273H Interacts with Replicating DNA and PARP1 in Breast Cancer.

Over 80% of triple-negative breast cancers (TNBC) express mutant p53 (mtp53) and some contain oncogenic gain-of-function (GOF) p53. We previously reported that GOF mtp53 R273H upregulates the chromatin association of mini chromosome maintenance (MCM) proteins MCM2-7 and PARP and named this the mtp53-PARP-MCM axis. In this study, we dissected the function and association between mtp53 and PARP using a number of different cell lines, patient-derived xenografts (PDX), tissue microarrays (TMA), and The Cancer Genome Atlas (TCGA) database. Endogenous mtp53 R273H and exogenously expressed R273H and R248W bound to nascent 5-ethynyl-2´-deoxyuridine-labeled replicating DNA. Increased mtp53 R273H enhanced the association of mtp53 and PARP on replicating DNA. Blocking poly-ADP-ribose gylcohydrolase also enhanced this association. Moreover, mtp53 R273H expression enhanced overall MCM2 levels, promoted cell proliferation, and improved the synergistic cytotoxicity of treatment with the alkylating agent temozolomide in combination with the PARP inhibitor (PARPi) talazoparib. Staining of p53 and PARP1 in breast cancer TMAs and comparison with the TCGA database indicated a higher double-positive signal in basal-like breast cancer than in luminal A or luminal B subtypes. Higher PARP1 protein levels and PAR proteins were detected in mtp53 R273H than in wild-type p53-expressing PDX samples. These results indicate that mtp53 R273H and PARP1 interact with replicating DNA and should be considered as dual biomarkers for identifying breast cancers that may respond to combination PARPi treatments. SIGNIFICANCE: p53 gain-of-function mutant 273H and PARP1 interact with replication forks and could serve as potential biomarkers for breast cancer sensitivity to PARP inhibitors. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/3/394/F1.large.jpg.

Preclinical and first-in-human-brain-cancer applications of [18F]poly (ADP-ribose) polymerase inhibitor PET/MR.

BACKGROUND: We report preclinical and first-in-human-brain-cancer data using a targeted poly (ADP-ribose) polymerase 1 (PARP1) binding PET tracer, [18F]PARPi, as a diagnostic tool to differentiate between brain cancers and treatment-related changes. METHODS: We applied a glioma model in p53-deficient nestin/tv-a mice, which were injected with [18F]PARPi and then sacrificed 1 h post-injection for brain examination. We also prospectively enrolled patients with brain cancers to undergo dynamic [18F]PARPi acquisition on a dedicated positron emission tomography/magnetic resonance (PET/MR) scanner. Lesion diagnosis was established by pathology when available or by Response Assessment in Neuro-Oncology (RANO) or RANO-BM response criteria. Resected tissue also underwent PARPi-FL staining and PARP1 immunohistochemistry. RESULTS: In a preclinical mouse model, we illustrated that [18F]PARPi crossed the blood-brain barrier and specifically bound to PARP1 overexpressed in cancer cell nuclei. In humans, we demonstrated high [18F]PARPi uptake on PET/MR in active brain cancers and low uptake in treatment-related changes independent of blood-brain barrier disruption. Immunohistochemistry results confirmed higher PARP1 expression in cancerous than in noncancerous tissue. Specificity was also corroborated by blocking fluorescent tracer uptake with an excess unlabeled PARP inhibitor in patient cancer biospecimen. CONCLUSIONS: Although larger studies are necessary to confirm and further explore this tracer, we describe the promising performance of [18F]PARPi as a diagnostic tool to evaluate patients with brain cancers and possible treatment-related changes.

[18F]FE-OTS964: a Small Molecule Targeting TOPK for In Vivo PET Imaging in a Glioblastoma Xenograft Model.

PURPOSE: Lymphokine-activated killer T cell-originated protein kinase (TOPK) is a fairly new cancer biomarker with great potential for clinical applications. The labeling of a TOPK inhibitor with F-18 can be exploited for positron emission tomography (PET) imaging allowing more accurate patient identification, stratification, and disease monitoring. PROCEDURES: [18F]FE-OTS964 was produced starting from OTS964, a preclinical drug which specifically binds to TOPK, and using a two-step procedure with [18F]fluoroethyl p-toluenesulfonate as a prosthetic group. Tumors were generated in NSG mice by subcutaneous injection of U87 glioblastoma cells. Animals were injected with [18F]FE-OTS964 and PET imaging and ex vivo biodistribution analysis was carried out. RESULTS: [18F]FE-OTS964 was successfully synthesized and validated in vivo as a PET imaging agent. The labeling reaction led to 15.1 ± 7.5 % radiochemical yield, 99 % radiochemical purity, and high specific activity. Chemical identity of the radiotracer was confirmed by co-elution on an analytical HPLC with a cold-labeled standard. In vivo PET imaging and biodistribution analysis showed tumor uptake of 3.06 ± 0.30 %ID/cc, which was reduced in animals co-injected with excess blocking dose of OTS541 to 1.40 ± 0.42 %ID/cc. CONCLUSIONS: [18F]FE-OTS964 is the first TOPK inhibitor for imaging purposes and may prove useful in the continued investigation of the pharmacology of TOPK inhibitors and the biology of TOPK in cancer patients.

A Retrospective: 10 Years of Oligo(phenylene-ethynylene) Electrolytes: Demystifying Nanomaterials.

In this retrospective, we first reviewed the synthesis of the oligo(phenylene-ethynylene) electrolytes (OPEs) we created in the past 10 years. Since the general antimicrobial activity of these OPEs had been reported in our previous account in Langmuir, we are focusing only on the unusual spectroscopic and photophysical properties of these OPEs and their complexes with anionic scaffolds and detergents in this Feature Article. We applied classical all-atom MD simulations to study the hydrogen bonding environment in the water surrounding the OPEs with and without detergents present. Our finding is that OPEs could form a unit cluster or unit aggregate with a few oppositely charged detergent molecules, indicating that the photostability and photoreactivity of these OPEs might be considerably altered with important consequences to their activity as antimicrobials and fluorescence-based sensors. Thus, in the following sections, we showed that OPE complexes with detergents exhibit enhanced light-activated biocidal activity compared to either OPE or detergent individually. We also found that similar complexes between certain OPEs and biolipids could be used to construct sensors for the enzyme activity. Finally, the OPEs could covalently bind to microsphere surfaces to make a bactericidal surface, which is simpler and more ordered than the surface grafted from microspheres with polyelectrolytes. In the Conclusions and Prospects section, we briefly summarize the properties of OPEs developed so far and future areas for investigation.

Discriminating radiation injury from recurrent tumor with [18F]PARPi and amino acid PET in mouse models.

BACKGROUND: Radiation injury can be indistinguishable from recurrent tumor on standard imaging. Current protocols for this differential diagnosis require one or more follow-up imaging studies, long dynamic acquisitions, or complex image post-processing; despite much research, the inability to confidently distinguish between these two entities continues to pose a significant dilemma for the treating clinician. Using mouse models of both glioblastoma and radiation necrosis, we tested the potential of poly(ADP-ribose) polymerase (PARP)-targeted PET imaging with [18F]PARPi to better discriminate radiation injury from tumor. RESULTS: In mice with experimental radiation necrosis, lesion uptake on [18F]PARPi-PET was similar to contralateral uptake (1.02 ± 0.26 lesion/contralateral %IA/ccmax ratio), while [18F]FET-PET clearly delineated the contrast-enhancing region on MR (2.12 ± 0.16 lesion/contralateral %IA/ccmax ratio). In mice with focal intracranial U251 xenografts, tumor visualization on PARPi-PET was superior to FET-PET, and lesion-to-contralateral activity ratios (max/max, p = 0.034) were higher on PARPi-PET than on FET-PET. CONCLUSIONS: A murine model of radiation necrosis does not demonstrate [18F]PARPi avidity, and [18F]PARPi-PET is better than [18F]FET-PET in distinguishing radiation injury from brain tumor. [18F]PARPi-PET can be used for discrimination between recurrent tumor and radiation injury within a single, static imaging session, which may be of value to resolve a common dilemma in neuro-oncology.

PARP-1-Targeted Radiotherapy in Mouse Models of Glioblastoma.

The DNA repair enzyme poly(ADP-ribose) polymerase 1 (PARP-1) is overexpressed in glioblastoma, with overall low expression in healthy brain tissue. Paired with the availability of specific small molecule inhibitors, PARP-1 is a near-ideal target to develop novel radiotherapeutics to induce DNA damage and apoptosis in cancer cells, while sparing healthy brain tissue. Methods: We synthesized an 131I-labeled PARP-1 therapeutic and investigated its pharmacology in vitro and in vivo. A subcutaneous tumor model was used to quantify retention times and therapeutic efficacy. A potential clinical scenario, intratumoral convection-enhanced delivery, was mimicked using an orthotopic glioblastoma model combined with an implanted osmotic pump system to study local administration of 131I-PARPi (PARPi is PARP inhibitor). Results:131I-PARPi is a 1(2H)-phthalazinone, similar in structure to the Food and Drug Administration-approved PARP inhibitor AZD-2281. In vitro studies have shown that 131I-PARPi and AZD-2281 share similar pharmacologic profiles. 131I-PARPi delivered 134.1 cGy/MBq intratumoral injected activity. Doses to nontarget tissues, including liver and kidney, were significantly lower. Radiation damage and cell death in treated tumors were shown by p53 activation in U87-MG cells transfected with a p53-bioluminescent reporter. Treated mice showed significantly longer survival than mice receiving vehicle (29 vs. 22 d, P < 0.005) in a subcutaneous model. Convection-enhanced delivery demonstrated efficient retention of 131I-PARPi in orthotopic brain tumors, while quickly clearing from healthy brain tissue. Conclusion: Our results demonstrate 131I-PARPi's high potential as a therapeutic and highlight PARP's relevance as a target for radionuclide therapy. Radiation plays an integral role in brain tumor therapy, and radiolabeled PARP therapeutics could ultimately lead to improvements in the standard of care.

Detergent-induced self-assembly and controllable photosensitizer activity of diester phenylene ethynylenes.

Photodynamic therapy, in which malignant tissue is killed by targeted light exposure following administration of a photosensitizer, can be a valuable treatment modality but currently relies on passive transport and local irradiation to avoid off-target oxidation. We present a system of excited-state control for truly local delivery of singlet oxygen. An anionic phenylene ethynylene oligomer is initially quenched by water, producing minimal fluorescence and no measurable singlet oxygen generation. When presented with a binding partner, in this case an oppositely charged surfactant, changes in solvent microenvironment result in fluorescence unquenching, restoration of intersystem crossing to the triplet state, and singlet oxygen generation, as assayed by transient absorption spectroscopy and chemical trapping. This solvation-controlled photosensitizer model has possible applications as a theranostic agent for, for example, amyloid diseases.

Substituent, Charge, and Size Effects on the Fluorogenic Performance of Amyloid Ligands: A Small-Library Screening Study.

Developing new molecular ligands for the direct detection and tracking of amyloid protein aggregates is key to understanding and defeating myriad neurodegenerative and other disorders including Alzheimer's and Parkinson's diseases. A crucial factor in the performance of an amyloid dye is its ability to detect the amyloid structural motif independent of the sequence of the amyloid-forming protomer. The current study investigates structure-function relationships of a class of novel phenyleneethynylene (PPE)-based dyes and fluorescent polymers using amyloid fibrils formed by two model proteins: lysozyme and insulin. A small library of 18 PPE compounds that vary in molecular weights, charge densities, water solubilities, and types and geometries of functional groups was tested. One compound, the small anionic oligo(p-phenylene ethynylene) electrolyte OPE1, was identified as a selective sensor for the amyloid conformation of both lysozyme and insulin. On the basis of protein binding and photophysical changes observed in the dye from this set of PPE compounds, keys to the selective detection of the amyloid protein conformation include moderate size, negative charge, and substituents that provide high microenvironment sensitivity to the fluorescence yield. These principles can serve as a guide for the further refinement of the effective amyloid-sensing molecules.

Antifungal Properties of Cationic Phenylene Ethynylenes and Their Impact on ß-Glucan Exposure.

Candida species are the cause of many bloodstream infections through contamination of indwelling medical devices. These infections account for a 40% mortality rate, posing a significant risk to immunocompromised patients. Traditional treatments against Candida infections include amphotericin B and various azole treatments. Unfortunately, these treatments are associated with high toxicity, and resistant strains have become more prevalent. As a new frontier, light-activated phenylene ethynylenes have shown promising biocidal activity against Gram-positive and -negative bacterial pathogens, as well as the environmental yeast Saccharomyces cerevisiae In this study, we monitored the viability of Candida species after treatment with a cationic conjugated polymer [poly(p-phenylene ethynylene); PPE] or oligomer ["end-only" oligo(p-phenylene ethynylene); EO-OPE] by flow cytometry in order to explore the antifungal properties of these compounds. The oligomer was found to disrupt Candida albicans yeast membrane integrity independent of light activation, while PPE is able to do so only in the presence of light, allowing for some control as to the manner in which cytotoxic effects are induced. The contrast in killing efficacy between the two compounds is likely related to their size difference and their intrinsic abilities to penetrate the fungal cell wall. Unlike EO-OPE-DABCO (where DABCO is quaternized diazabicyclo[2,2,2]octane), PPE-DABCO displayed a strong propensity to associate with soluble ß-glucan, which is expected to inhibit its ability to access and perturb the inner cell membrane of Candida yeast. Furthermore, treatment with PPE-DABCO unmasked Candida albicans ß-glucan and increased phagocytosis by Dectin-1-expressing HEK-293 cells. In summary, cationic phenylene ethynylenes show promising biocidal activity against pathogenic Candida yeast cells while also exhibiting immunostimulatory effects.

Oligo(p-phenylene ethynylene) Electrolytes: A Novel Molecular Scaffold for Optical Tracking of Amyloids.

Finding new optical probes to detect and track amyloid protein aggregates is key to understanding and defeating the myriad of neurodegenerative and other diseases associated with these misfolded proteins. Herein we report that a series of fluorescent, soluble oligo(p-phenylene ethynylene)s (OPEs) are able to detect amyloids in vitro by massive binding-activated superluminescence, with low micromolar affinity and high selectivity for the amyloid conformer. The OPEs track the kinetics of amyloid fibril formation from native hen egg white lysozyme (HEWL) similarly to thioflavin T (ThT), and the dependence of binding affinity on OPE length supports the theory of a linear binding groove. We hypothesize, based on spectral properties, induced circular dichroism, and previous work in analogous systems, that the fluorescence turn-on mechanism is a combination of the reduction of static solvent-mediated quenching at the ethyl ester end groups of the phenylene ethynylene fluorophore and the formation of chiral J-type aggregates templated on the amyloid fibril surface.