Zebrafish tumour xenograft models: a prognostic approach to epithelial ovarian cancer

Epithelial ovarian cancer (EOC) is the gynaecological malignancy with highest mortality. Although adjuvant treatment with carboplatin and paclitaxel leads to an objective response in ~80% of these patients, a majority will relapse within two years. Better methods for assessing long-term treatment outcomes are needed. To address this, we established safe and efficacious doses of carboplatin and paclitaxel using IGROV-1 zebrafish-CDX models. Then fluorescently-labelled cell suspensions from 83 tumour biopsies collected at exploratory laparotomy of women with suspected EOC were generated and 37 (45%) were successfully implanted in zebrafish larvae. Among these 19 of 27 pathology-confirmed EOC samples (70%) engrafted. These zebrafish patient-derived tumour xenograft (ZTX) models were treated with carboplatin or paclitaxel and tumour growth/regression and metastatic dissemination were recorded. In a subgroup of nine patients, four ZTX models regressed during carboplatin treatment. All four corresponding patients had >24 months PFS. Furthermore, both ZTX models established from two patients having <24 months PFS failed to regress during carboplatin treatment. Seven of eight models seeding <6 metastatic cells were established from patients having >24 months PFS. In eleven of fourteen patients, FIGO stage I + II or III tumours gave rise to ZTX models seeding <4 or >4 metastatic cells, respectively. In conclusion, ZTX models predicted patients having >24 or <24 months PFS, based on response/no response to carboplatin. Furthermore, high metastatic dissemination in ZTX models correlated to shorter PFS and more advanced disease at diagnosis. These preliminary results suggest that ZTX models could become a useful prognostic tool in EOC treatment planning.

RhoB expression associated with chemotherapy response and prognosis in colorectal cancer

PURPOSE

To examine the role of RhoB expression in relation to chemotherapy response, clinical outcomes and associated signaling pathways in colorectal cancer patients.

MATERIALS AND METHODS

The study included 5 colon cancer cell lines, zebrafish embryos and 260 colorectal cancer patients treated with 5-fluorouracil (5-FU) and oxaliplatin (OXL). The methods consisted of CRISPR/Cas9, reactive oxygen species (ROS), caspase-3 activity, autophagy flux, in-silico RNA sequencing and immunohistochemistry. Gene expression analysis and pathway analysis were conducted using RNA-seq data.

RESULTS

All cancer lines tested, including SW480, SW480-KO13 (RhoB knockout), SW480-KO55 (RhoB knockout), HCT116 and HCT116-OE (RhoB overexpressed), exhibited cytotoxicity to 5-FU and OXL. RhoB knockout cell lines demonstrated significantly reduced migration compared to the control cell lines. Furthermore, RhoB played a role in caspase-3-dependent apoptosis, regulation of ROS production and autophagic flux. The mRNA sequencing data indicated lower expression levels of oncogenes in RhoB knockout cell lines. The zebrafish model bearing SW480-KO showed a light trend toward tumor regression. RhoB expression by immunohistochemistry in patients was increased from normal mucosa to tumor samples. In patients who received chemotherapy, high RhoB expression was related to worse survival compared to low RhoB expression. Furthermore, the molecular docking analysis revealed that OXL had a higher binding affinity for RhoB than 5-FU, with a binding affinity of -7.8 kcal/mol and HADDOCK predicted molecular interactions between RhoB and caspase 3 protein. Gene-set enrichment analysis supported these findings, showing that enrichment of DNA damage response pathway and p53 signaling in RhoB overexpression treatment group, while the RhoB knockout treatment group exhibited enrichment in the negative regulation pathway of cell migration.

CONCLUSION

RhoB was negatively associated with chemotherapy response and survival in colorectal cancers. Therefore, RhoB inhibition may enhance chemotherapeutic responses and patient survival.

A Combined Quantum Mechanics and Molecular Mechanics Approach for Simulating the Optical Properties of DNA-Stabilized Silver Nanoclusters

DNA-stabilized silver nanoclusters have emerged as an intriguing type of nanomaterial due to their unique optical and electronic properties, with potential applications in areas such as biosensing and imaging. The development of efficient methods for modeling these properties is paramount for furthering the understanding and utilization of these clusters. In this study, a hybrid quantum mechanical and molecular mechanical approach for modeling the optical properties of a DNA-templated silver nanocluster is evaluated. The influence of different parameters, including ligand fragmentation, damping, embedding potential, basis set, and density functional, is investigated. The results demonstrate that the most important parameter is the type of atomic properties used to represent the ligands, with isotropic dipole-dipole polarizabilities outperforming the rest. This underscores the importance of an appropriate representation of the ligands, particularly through the selection of the properties used to represent them. Moreover, the results are compared to experimental data, showing that the applied methodology is reliable and effective for the modeling of DNA-stabilized silver nanoclusters. These findings offer valuable insights that may guide future computational efforts to explore and harness the potential of these novel systems.

A recursive cell multipole method for atomistic electrodynamics models

For large plasmonic nanoparticles, retardation effects become important once their length becomes comparable to the wavelength of light. However, most models do not incorporate retardation effects due to the high computational cost of solving for the optical properties of large atomistic electrodynamics systems. In this work, we derive and implement a recursive fast multipole method (FMM) in Cartesian coordinates that includes retardation effects. In this method, higher-order electrodynamic interaction tensors used for the FMM are calculated recursively, thus greatly reducing the implementation complexity of the model. This method allows for solving of the optical properties of large atomistic nanoparticles with controlled accuracy; in practice, taking the expansion to the fifth order provides a good balance of accuracy and computational time. Finally, we study the effects retardation has on the near- and far-field properties of large plasmonic nanoparticles with over a million atoms using this method. We specifically focus on nanorods and their dimers, which are known to generate highly confined fields in their junctions. In the future, this method can be applied to simulations in which accurate near-field properties are required, such as surface-enhanced Raman scattering.

Modeling the near-field effect on molecular excited states using the discrete interaction model/quantum mechanical method

Strong light-matter interactions significantly modify the optical properties of molecules in the vicinity of plasmonic metal nanoparticles. Since the dimension of the plasmonic cavity approaches that of the molecules, it is critical to explicitly describe the nanoparticle junctions. In this work, we use the discrete interaction model/quantum mechanical (DIM/QM) method to model the coupling between the plasmonic near-field and molecular excited states. DIM/QM is a combined electrodynamics/quantum mechanical model that uses an atomistic description of the nanoparticle. We extend the DIM/QM method to include the local field effects in the sum-over-state formalism of time-dependent density functional theory. As a test of the method, we study the interactions between small organic chromophores and metal nanoparticles. In particular, we examine how the inclusion of multiple electronic transitions and intermolecular interactions modify the coupling between molecules and nanoparticles. Using the sum-over-state formalism of DIM/QM, we show that two-state models break down when the plasmon excitation is detuned from the molecular excitations. To gain further insight, we compare the simple coupled-dipole model (CDM) with the DIM/QM model. We find that CDM works well for simple systems but fails when going beyond the single molecule or single nanoparticle cases. We also find that the coupling depends strongly on the site of the nanoparticle in which the chromophore couples to. Our work suggests the importance of explicitly describing the cavity to capture the atomistic level local field environment in which the molecule strongly couples to.

Seeking a Au-C stretch on gold nanoparticles with 13C-labeled N-heterocyclic carbenes

Gold nanoparticles were functionalized with natural abundance and 13C-labeled N-heterocyclic carbenes (NHCs) to investigate the Au-C stretch. A combinatorial approach of surface enhanced Raman spectroscopy (SERS) and density-functional theory (DFT) calculations highlighted vibrational modes significantly impacted by isotopic labeling at the carbene carbon. Critically, no isotopically-impacted stretching mode showed majority Au-C character.

Elucidating the Mystery of DNA-Templating Effects on a Silver Nanocluster

This presentation considers the effects that DNA-templating has on the optical properties of a 16-atom silver cluster. To accomplish this, hybrid quantum mechanical and molecular mechanical simulations of a Ag₁₆-DNA complex have been carried out and compared with pure time-dependent density functional theory calculations of two Ag₁₆ clusters in vacuum. The presented results show that the templating DNA polymers both red-shift the one-photon absorption of the silver cluster and increase its intensity. This occurs through a change in cluster shape prompted by the structural constraints of the DNA ligands combined with silver-DNA interactions. The overall charge of the cluster also contributes to the observed optical response, as oxidation of the cluster results in a simultaneous blue-shift of the one-photon absorption and a decrease in intensity. Additionally, the changes in shape and environment also lead to a blue-shift and enhancement of the two-photon absorption.

Using Surface-Enhanced Raman Spectroscopy to Unravel the Wingtip-Dependent Orientation of N-Heterocyclic Carbenes on Gold Nanoparticles

N-Heterocyclic carbenes (NHCs) are an attractive alternative to thiol ligands when forming self-assembled monolayers on noble-metal surfaces; however, relative to the well-studied thiol monolayers, comparatively little is known about the binding, orientation, and packing of NHC monolayers. Herein, we combine surface-enhanced Raman spectroscopy (SERS) and first-principles theory to investigate how the alkyl "wingtip" groups, i.e., those attached to the nitrogens of N-heterocyclic carbenes, affect the NHC orientation on gold nanoparticles. Consistent with previous literature, smaller wingtip groups lead to stable flat configurations; surprisingly, bulkier wingtips also have stable flat configurations likely due to the presence of an adatom. Comparison of experimental SERS results with the theoretically calculated spectra for flat and vertical configurations shows that we are simultaneously detecting both NHC configurations. In addition to providing information on the adsorbate geometry, this study highlights the extreme SERS enhancement of vibrational modes perpendicular to the surface.

Understanding chemical enhancements of surface-enhanced Raman scattering using a Raman bond model for extended systems

In this work, we extend a previously developed Raman bond model to periodic slab systems for interpreting chemical enhancements of surface-enhanced Raman scattering (SERS). The Raman bond model interprets chemical enhancements as interatomic charge flow modulations termed Raman bonds. Here, we show that the model offers a unified interpretation of chemical enhancements for localized and periodic systems. As a demonstration of the model, we study systems consisting of CO and pyridine molecules on Ag clusters and slabs. We find that for both localized and periodic systems the dominant Raman bonds are distributed near the molecule-metal interface and the chemical enhancements are determined by a common Raman bond pattern. The effects of surface coverages, thickness, and roughness on the chemical enhancements are studied, which shows that decreasing surface coverages or creating surface roughness increases chemical enhancements. In both of these cases, the inter-fragment charge flow connectivity is improved due to more dynamic polarization at the interface. The chemical enhancement is shown to scale with the inter-fragment charge flow to the fourth power. Since the inter-fragment charge flow is determined by the charge transfer excitation energy, the Raman bond model is connected to the transition based analysis of chemical enhancements. We also show that SERS spectra of localized and periodic systems normalized by inter-fragment charge flows can be unified. In summary, the Raman bond model offers a unique framework for understanding SERS spectra in terms of Raman bond distributions and offers a connection between localized and periodic model systems of SERS studies.

Epidemiology and impact of frailty in patients with atrial fibrillation in Europe

BACKGROUND

Frailty is a medical syndrome characterised by reduced physiological reserve and increased vulnerability to stressors. Data regarding the relationship between frailty and atrial fibrillation (AF) are still inconsistent.

OBJECTIVES

We aim to perform a comprehensive evaluation of frailty in a large European cohort of AF patients.

METHODS

A 40-item frailty index (FI) was built according to the accumulation of deficits model in the AF patients enrolled in the ESC-EHRA EORP-AF General Long-Term Registry. Association of baseline characteristics, clinical management, quality of life, healthcare resources use and risk of outcomes with frailty was examined.

RESULTS

Among 10,177 patients [mean age (standard deviation) 69.0 (11.4) years, 4,103 (40.3%) females], 6,066 (59.6%) were pre-frail and 2,172 (21.3%) were frail, whereas only 1,939 (19.1%) were considered robust. Baseline thromboembolic and bleeding risks were independently associated with increasing FI. Frail patients with AF were less likely to be treated with oral anticoagulants (OACs) (odds ratio 0.70, 95% confidence interval 0.55-0.89), especially with non-vitamin K antagonist OACs and managed with a rhythm control strategy, compared with robust patients. Increasing frailty was associated with a higher risk for all outcomes examined, with a non-linear exponential relationship. The use of OAC was associated with a lower risk of outcomes, except in patients with very/extremely high frailty.

CONCLUSIONS

In this large cohort of AF patients, there was a high burden of frailty, influencing clinical management and risk of adverse outcomes. The clinical benefit of OAC is maintained in patients with high frailty, but not in very high/extremely frail ones.

POS1107 CHANGE IN ULTRASOUND-BASED KNEE JOINT INFLAMMATORY MARKERS AFTER WEIGHT LOSS IN PATIENTS WITH OSTEOARTHRITIS: A PROSPECTIVE COHORT STUDY

Background

Pain and impaired function due to knee OA (KOA) can be reduced with weight loss in obese patients. The role of synovitis in symptom improvement after weight loss is not fully understood. MRI and ultrasound (US) can be used in assessment of inflammation in the KOA. Knee joint synovitis assessed by MRI does not seem to change with weight loss, however, the typical MRI score is semiquantitative, which might be less sensitive to change than a quantitative score. US has a higher resolution than MRI and borders between synovium and surrounding tissues might be clearer allowing for a quantitative score. Changes in US-based synovitis following a weight has not been assessed.

Objectives

To assess changes in US synovitis in the knee joint after 8 weeks low-calorie weight loss intervention in overweight persons with KOA.

Methods

prospective cohort study (NCT02931370) including overweight persons (BMI ≥ 27 kg/m2) with KOA. Weight loss was induced by an intensive 8-week diet (1200 kcal/day), participants had symptomatic and radiographically confirmed KOA (KL grade 1-3). At week 0 and 8 all participants filled in the KOOS questionnaire assessing pain, physical function, symptoms, quality of life, and sport/recreation in relation to KOA (0= worst; 100=best). Furthermore, an US examination of the most affected knee was performed assessing the amount of synovial hypertrophy (SH) and effusion in medial and lateral recesses. The US examination was performed in a strictly standardized manner on a high-end US machine. The subsequent image evaluation was done both according to a semiquantitative score from 0 to 3 (0=no SH/effusion and 3=pronounced SH/effusion) and a quantitative scoring system using specific anatomic landmarks to measure the synovial hypertrophy/effusion in millimeter.

Statistical analyses were performed on the per protocol population (participants completing diet intervention).

Results

135 patients with KOA with a mean age of 60y (SD 9.8), a body weight of 106.0 kg (SD18.5) and mean BMI of 36.4 (SD5.4) completed the weight loss intervention. After the diet intervention mean weight change was -12.8 kg (95%CI -13.3 to -12.4) and the reductions in SH were -0.3mm (95%CI -0.5 to -0.1) (medial recess) and -0.4mm (95%CI -0.6 to -0.1) (lateral recess), and -0.03 (-0.13 to 0.07) (medial recess) and -0.07 (-0.20 to 0.05) using the semi-quantitative system. The mean change in the KOOS subscales range from 15.8 (sport/recreation) to 7.4 (QoL). See Table 1.

Table 1.n=135BaselineChangeMean (SD)Mean (95%CI)PAge60.0 (9.8)--Females, n (%)87 (64.4%)--BMI36.4 (5.4)-4.4 (-4.5 to -4.3)<.0001KL-scores; 122 (16.3%)--KL-scores; 256 (41.5%)--KL-scores; 357 (42.2%)--KL-scores; 40 (0%)--Synovial HypertrophyMedial, mm3.8 (1.8)-0.3 (-0.5 to -0.1)0.0198Lateral, mm5.3 (2.3)-0.4 (-0.6 to -0.1)0.0210Medial, 0-31.2 (0.6)-0.03 (-0.13 to 0.07)0.5584Lateral, 0-31.8 (0.8)-0.07 (-0.20 to 0.05)0.2311KOOS, 0-100Pain64.1 (16.0)12 (10.2 to 13.8)<.0001Function68.4 (17.3)14 (12.4 to 15.6)<.0001Symptoms68.9 (16.4)9 (7.2 to 10.8)<.0001Sports/Recreation35.9 (24.0)15.8 (13.2 to 18.3)<.0001QoL43.8 (17.5)7.4 (5.7 to 9.2)<.0001

SD = Standard Deviation; CI = Confidence Interval; BMI = Body Mass Index;

KOOS = Knee injury and Osteoarthritis Outcome Score; QoL = Knee-related Quality of Life

Conclusion

Quantitative measures of SH assessed by US decreased after a significant weight loss over 8-weeks; however, no linear association with weight loss magnitude was seen. A weak correlation between changes in SH in the lateral recess and change in pain was seen. This indicates changes in SH assessed by US examination is associated with a low-calorie diet but seems uncoupled with weight loss magnitude. The weight loss induced changes in synovitis and KOA symptoms seem vaguely related.

Disclosure of Interests

None declared

Ad aurum: tunable transfer of N-heterocyclic carbene complexes to gold surfaces

The exceptional stability of N-heterocyclic carbene (NHC) monolayers on gold surfaces and nanoparticles (AuNPs) is enabling new and diverse applications from catalysis to biomedicine.

Local-Field Effects in Linear Response Properties within a Polarizable Frozen Density Embedding Method

In this work, we present a polarizable frozen density embedding (FDE) method for calculating polarizabilities of coupled subsystems. The method (FDE-pol) combines a FDE method with an explicit polarization model such that the expensive freeze/thaw cycles can be bypassed, and approximate nonadditive kinetic potentials are avoided by enforcing external orthogonality between the subsystems. To describe the polarization of the frozen environment, we introduce a Hirshfeld partition-based density-dependent method for calculating the atomic polarizabilities of atoms in molecules, which alleviates the need to fit the atomic parameters to a specific system of interest or to a larger general set of molecules. We show that the Hirshfeld partition-based method predicts molecular polarizabilities close to the basis set limit, and thus, a single basis set-dependent scaling parameter can be introduced to improve the agreement against the reference polarizability data. To test the model, we characterized the uncoupled and coupled response of small interacting molecular complexes. Here, the coupled response properties include the perturbation of the frozen system due to the external perturbation which is ignored in the uncoupled response. We show that FDE-pol can accurately reproduce both the exact uncoupled polarizability and the coupled polarizabilities of the supermolecular systems. Using damped response theory, we also demonstrate that the coupled frequency-dependent polarizability can be described by including local field effects. The results emphasize the necessity of including local-field effects for describing the response properties of coupled subsystems, as well as the importance of accurate atomic polarizability models.

Interleukin-33 is a Novel Immunosuppressor that Protects Cancer Cells from TIL Killing by a Macrophage-Mediated Shedding Mechanism

Recognition of specific antigens expressed in cancer cells is the initial process of cytolytic T cell-mediated cancer killing. However, this process can be affected by other non-cancerous cellular components in the tumor microenvironment. Here, it is shown that interleukin-33 (IL-33)-activated macrophages protect melanoma cells from tumor-infiltrating lymphocyte-mediated killing. Mechanistically, IL-33 markedly upregulates metalloprotease 9 (MMP-9) expression in macrophages, which acts as a sheddase to trim NKG2D, an activating receptor expressed on the surface of natural killer (NK) cells, CD8+ T cells, subsets of CD4+ T cells, iNKT cells, and γδ T cells. Further, MMP-9 also cleaves the MHC class I molecule, cell surface antigen-presenting complex molecules, expressed in melanoma cells. Consequently, IL-33-induced macrophage MMP-9 robustly mitigates the tumor killing-effect by T cells. Genetic and pharmacological loss-of-function of MMP-9 sheddase restore T cell-mediated cancer killing. Together, these data provide compelling in vitro and in vivo evidence showing novel mechanisms underlying the IL-33-macrophage-MMP-9 axis-mediated immune tolerance against cancer cells. Targeting each of these signaling components, including IL-33 and MMP-9 provides a new therapeutic paradigm for improving anticancer efficacy by immune therapy.

Abstract 3000: Zebrafish tumor-derived xenograft-models for improved diagnosis and treatment planning in ovarian cancer patients

Precision medicine approaches based on DNA or RNA analyses, are often not identifying actionable mutations in the patients, and have not been established for predicting presonse to commonly used drugs such as platins and taxols. In epithelial ovarian cancer (EOC), where paclitaxel and carboplatin is the most commonly used first-line treatment, however, local practice and a host of clinical studies have/are evaluating combinations with other drugs, implying that first line treatment regimens may vary in different countries and regions. As EOC patients that respond to first-line treatment have much better prognosis that those who don't, there is an urgent need for methods to predict the outcome to various available first line therapies, prior to treatment onset, so that the optimal treatment can be identified and offered to every patient. Zebrafish tumor xenograft (ZTX) models have recently been used to predict treatment outcome to first line therapy in multiple myeloma, neuroendocrine cancer, colorectal cancer and gastric cancer, but these studies have been small case studies including only a few patients. Furthermore, EOC, and the main drugs used to treat them have, however, not been studied in ZTX models in the past. Here we present results from the first 81 patients in an ongoing clinical study to delineate the sensitivity and specificity of ZTX models to predict treatment outcome to paclitaxel and carboplatin. Of these 81 patients, 21 presented with a primary tumor only, whereas 60 had metastatic disease. To date, 25 patient-derived tumor xenograft models have been developed by random selection of samples from this patient cohort, of which 12 were from paired primary and metastatic lesions from 6 patients. We show that tumors generated from metastatic omental lesions exhibited similar growth and metastatic dissemination as those generated from samples taken from ovarian lesions. Among the 25 patient models generated, 15 were analyzed for efficacy of paclitaxel and carboplatin in the ZTX models. We found that 11 of 15 responded to paclitaxel, 12 of 15 to carboplatin and 10 of 15 to both drugs. In conclusion, ZTX EOC models established from surgical samples allow prediction of treatment outcomes to 1st line treatment and thereby may aid treatment planning in the future.

Citation Format: Karthik Selvaraj, Malin Vildevall, Lina Wirestam, Zaheer Ali, Anna Erkstam, Annelie Abrahamsson, Åsa Rydmark Kersley, Preben Kjölhede, Stig Linder, Charlotta Dabrosin, Anna Fahlgren, Lasse Jensen. Zebrafish tumor-derived xenograft-models for improved diagnosis and treatment planning in ovarian cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 3000.

A discrete interaction model/quantum mechanical method for simulating surface-enhanced Raman spectroscopy in solution

Since surface-enhanced Raman scattering (SERS) is of considerable interest for sensing applications in aqueous solution, the role that solvent plays in the spectroscopy must be understood. However, these efforts are hindered due to a lack of simulation approaches for modeling solvent effects in SERS. In this work, we present an atomistic electrodynamics-quantum mechanical method to simulate SERS in aqueous solution based on the discrete interaction model/quantum mechanical method. This method combines an atomistic electrodynamics model of the nanoparticle with a time-dependent density functional theory description of the molecule and a polarizable embedding method for the solvent. The explicit treatment of solvent molecules and nanoparticles results in a large number of polarizable dipoles that need to be considered. To reduce the computational cost, a simple cut-off based approach has been implemented to limit the number of dipoles that need to be treated without sacrificing accuracy. As a test of this method, we have studied how solvent affects the SERS of pyridine in the junction between two nanoparticles in aqueous solution. We find that the solvent leads to an enhanced SERS due to an increased local field at the position of the pyridine. We further demonstrate the importance of both image field and local field effects in determining the enhancements and the spectral signatures. Our results show the importance of describing the local environment due to the solvent molecules when modeling SERS.

Monitoring Reaction Intermediates in Plasma-Driven SO2, NO, and NO2 Remediation Chemistry Using In Situ SERS Spectroscopy

In situ surface-enhanced Raman scattering (SERS) spectroscopy is used to identify the key reaction intermediates during the plasma-based removal of NO and SO₂ under dry and wet conditions on Ag nanoparticles. Density functional theory (DFT) calculations are used to confirm the experimental observations by calculating the vibrational modes of the surface-bound intermediate species. Here, we provide spectroscopic evidence that the wet plasma increases the SO₂ and the NO_x removal through the formation of highly reactive OH radicals, driving the reactions to H₂SO₄ and HNO₃, respectively. We observed the formation of SO₃ and SO₄ species in the SO₂ wet-plasma-driven remediation, while in the dry plasma, we only identified SO₃ adsorbed on the Ag surface. During the removal of NO in the dry and wet plasma, both NO₂ and NO₃ species were observed on the Ag surface; however, the concentration of NO₃ species was enhanced under wet-plasma conditions. By closing the loop between the experimental and DFT-calculated spectra, we identified not only the adsorbed species associated with each peak in the SERS spectra but also their orientation and adsorption site, providing a detailed atomistic picture of the chemical reaction pathway and surface interaction chemistry.

Surface-enhanced hyper-Raman scattering of Rhodamine 6G isotopologues: Assignment of lower vibrational frequencies

We report a comprehensive experimental and theoretical study of the lower-wavenumber vibrational modes in the surface-enhanced hyper-Raman scattering (SEHRS) of Rhodamine 6G (R6G) and its isotopologue R6G-d4. Measurements acquired on-resonance with two different electronic states, S₁ and S₂, are compared to the time-dependent density functional theory computations of the resonance hyper-Raman spectra and electrodynamics-quantum mechanical computations of the SEHRS spectra on-resonance with S₁ and S₂. After accounting for surface orientation, we find excellent agreement between experiment and theory for both R6G and its isotopologue. We then present a detailed analysis of the complex vibronic coupling effects in R6G and the importance of surface orientation for characterizing the system. This combination of theory and experiment allows, for the first time, an unambiguous assignment of lower-wavenumber vibrational modes of R6G and its isotopologue R6G-d4.

Daunorubicin associated to lipid core nanoparticles reduces atherosclerotic lesions, inflammation and cardiotoxicity in atherosclerosis rabbit model

Introduction

Antiproliferative agents used in cancer chemotherapy have low toxicity and increased pharmacological action when carried into lipid core nanoparticles (LDE). LDE has similar structure to LDL and binds to LDL receptors through apo E it acquires in contact with plasma. Previously, we showed that treatment of rabbits with atherosclerosis with drugs such as taxanes and etoposide associate to LDE had pronounced reduction of the atherosclerotic lesions. In this study, we hypothesized whether daunorubicin (DNR) that belongs to another class of anti-cancer drugs, with a distinct mechanism of action and that has strong cardiotoxicity could also have effects against atherosclerosis.

Methods

Sixteen New Zealand male rabbits were fed with a 1% cholesterol diet for 8 weeks to induce atherosclerosis. After 4 weeks, the animals were treated weekly with LDE-DNR (6mg/kg, iv, n=9) or with LDE only (n=7). In addition, 3 animals without any intervention were used as a control group. Chow consumption, lipid and hematological profiles, body weight, and echocardiography were evaluated at baseline, pre-treatment and post-treatment. Morphometry and protein expression were performed to analyze the aortas.

Results

There was no difference in food intake and body weight for control, LDE and LDE-DNR groups. Total cholesterol, HDL-C, non-HDL-C and triglycerides increased in LDE and LDE-DNR groups when comparing baseline and post-treatment. Red blood cells decreased in LDE group at post-treatment in comparison to baseline, while LDE-DNR presented no such difference. Regarding aortic lesions of LDE-DNR group was 50% lower than LDE group. The protein expression of the inflammatory markers CD68, TNF-α and IL-6 in LDE-DNR was lower than LDE. Pro-apoptotic factors caspase 3, caspase 9 and BAX were also lower in LDE-DNR compared to LDE. Protein expression of vascular endothelial growth factor (VEGF) and vascular cell adhesion molecule (VCAM) was lower in the LDE-DNR group when compared to the LDE group. To test the cardiotoxicity of LDE-DNR, echocardiography was performed and observed that under LDE-DNR both systolic and diastolic function were preserved with no difference in cardiac mass in LDE-DNR when compared to control and LDE groups. However, LDE showed a significant increase in relative heart weight compared to control while LDE-DNR had no such difference. Treatment with LDE-DNR did not induce observable hematological toxicity.

Conclusion

The treatment with LDE-DNR reduced aortic lesions, diminished inflammatory and pro-apoptotic factors, diminished VCAM expression in the aorta and promoted cardiac preservation in a rabbit atherosclerosis model. In conclusion, LDE-DNR can be eligible for future developments in the quest for novel effective and safe treatments for atherosclerosis.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): FAPESP (Fundaçao de Amparo a Pesquisa do Estado de Sao Paulo)

Methotrexate associated with a lipid core nanoparticle prevented the dilation and dissection of the aortic arch in mice with Marfan syndrome

Introduction

Mutations in the fibrillin-1 gene result in dilation, dissection and rupture of the aorta, the main cause of mortality in patients with Marfan syndrome (MFS). Inflammation is associated with greater susceptibility to dissection and rupture of the aorta. Previously, we showed that methotrexate (MTX) carried in lipid core nanoparticles (LDE) had powerful anti-inflammatory and anti-proliferative effects on rheumatoid arthritis and atherosclerotic lesions induced in rabbits and improved myocardial infarction morphological and functional aspects in rats with ligation of left coronary artery. When MTX is associated to LDE, the uptake of the drug by the cells is increased several-fold, which conceivably endows MTX with enhanced action mechanisms and the drug toxicity is diminished.

Purpose

To investigate whether treatment with LDE-MTX can prevent the development of aortic arch lesions in a murine model of MFS.

Methods

mgΔloxPneo MFS murine model and wild-type mice were allocated in 3 groups of treatment: LDE only; MTX in commercial formulation; LDE-MTX. The treatment occurred weekly at a dose of 1mg/kg ip, between the 3rd and 6th month of life, period in which both dilation and dissection of the aortic arch are observed. After 12 weeks, the animals were submitted to echocardiography, morphometry and protein expression of the aortic arch.

Results

Compared to LDE and MTX groups, LDE-MTX treatment showed smaller lumen area of ascending and descending aorta and aortic arch segments in MFS mice. LDE-MTX also decreased the collagen volume fraction and the amount of aortic dissections, but did not affect the thickness of the vessel wall and the number of elastic fiber ruptures. The protein expression of the inflammatory markers CD68 (macrophages), CD3 (lymphocytes) and tumor necrosis factor alpha, of the apoptotic marker caspase 3 and of type 1 collagen were lower in MFS LDE-MTX group when compared to MFS mice treated with LDE and MTX. Moreover, treatment with LDE-MTX reduced TGF-β, ERK and the SMAD3 protein expression. Of note, CD68 and CD3 protein expression was positively correlated with the lumen area of the aortic arch (r2=0.36; p&lt;0.001), indicating the importance of inflammation for the aortic dilation. The increase in bioavailability of intracellular adenosine in MFS animals treated with LDE-MTX was suggested by the higher expression of A2a adenosine receptor and the lower expression of adenosine deaminase in the aortic arch.

Conclusion

Possibly by increasing the bioavailability of intracellular adenosine, LDE-MTX treatment had the ability to reduce the processes of inflammation, apoptosis and fibrosis that are consequent to fibrillin-1 mutation. By these means, LDE-MTX may conceivably prevent the development of the dilation and dissection in the aortic arch, the hallmarks of MFS, in this animal model.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo)

Treatment with methotrexate carried in lipid core nanoparticles prevents the development of diastolic dysfunction in septic rats

Introduction

In the development of sepsis, besides the dysregulation of the immune system and disturbances of several vital organs, life-threatening cardiac dysfunction often occurs. Previously, we showed that non-protein nanoparticles that resemble the lipid structure of low-density lipoprotein, termed LDE, concentrate in inflammatory sites. When incorporated in LDE, the cellular uptake of MTX increases several-fold compared to the uptake of commercial MTX. The novel LDE-MTX formulation was shown to have the ability to modulate the immune response in in rabbits with atherosclerosis and in rats with myocardial infarction. LDE-MTX reduced the inflammation and improved the post-infarction cardiac function by increasing the release of angiogenesis, thereby improving hypoxia. The aim of the current study was to test the hypothesis whether LDE-MTX could also improve the cardiac status in septic rats.

Methods

Septicemia was induced in Wistar rats by two I.P. injections of lipopolysaccharide (LPS, 10mg/kg) administered with a 24h interval. Rats were allocated to control group (CT, without sepsis; n=5) and 3 groups with sepsis: LDE (n=7), treated with LDE only; MTX (n=6), with commercial MTX (1mg/kg); and LDE-MTX (n=7), with LDE-MTX (1mg/kg). Echocardiography was performed 72h after sepsis induction. Animals were euthanised and LV tissues were collected for protein expression analysis of inflammatory, apoptotic, angiogenesis, hypoxia and adenosine bioavailability markers.

Results

Septic rats treated with LDE developed diastolic dysfunction and presented decreased diastolic volume and diameter of the LV. Treatment with LDE-MTX totally prevented the appearance of diastolic dysfunction and the alterations in LV diastolic dilation. Also, LDE-MTX treatment elicited cardiac hypertrophy through the increase of the thickness of septum and of the LV posterior wall. LDE-MTX increased LV mass and the relative heart weight, as compared to the other 3 groups. There were no differences in the protein expression of inflammatory (lymphocytes, tumor necrosis factor, interleukins) and apoptotic (caspases and B-cell lymphoma family) markers among the four groups. However, LDE-MTX showed higher expression of CD68 (macrophage marker). Angiogenesis was higher, while cellular hypoxia was lower in LDE-MTX, respectively represented by vascular endothelial growth factor (VEGF) and hypoxia-inducible factor 1 alpha, in comparison to the other 3 groups. The intracellular adenosine bioavailability was increased in LDE-MTX-treated animals, as promoted by the higher expression of the A1 receptor, as compared to CT.

Conclusion

The treatment with LDE-MTX was successful in precluding the appearance of the cardiac dysfunction associated to sepsis. This outcome was conceivably attained by different effects of the treatment observed here, such as those on angiogenesis, macrophage recruitment and adenosine bioavailability in the LV.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): FAPESP (Fundacao de Amparo a Pesquisa do Estado de Sao Paulo)

Alternating magnetic field mediated release of fluorophores from magnetic nanoparticles by hysteretic heating

This study explores the use of differential heating of magnetic nanoparticles with different sizes and compositions (MFe2O4 (M = Fe, Co)) for heteroplexed temporal controlled release of conjugated fluorophores from the surface of nanoparticles. By exploiting these differences, we were able to control the amount of hysteretic heating occurring with the distinct sets of magnetic nanoparticles using the same applied alternating magnetic field radio frequency (AMF-RF). Using thermally labile retro-Diels-Alder linkers conjugated to the surface of nanoparticles, the fluorescent payload from the different nanoparticles disengaged when sufficient energy was locally generated during hysteretic heating. 1H, 13C NMR, ESI-MS, and SIMS characterized the thermally responsive fluorescent cycloadducts used in this study; the Diels Alder cycloadducts were modeled using density functional theory (DFT) computations. The localized point heating of the different nanoparticle compositions drove the retro-Diels-Alder reaction at different times resulting in higher release rates of fluorophores from the CoFe2O4 compared to the Fe3O4 nanoparticles.

NWChem: Past, present, and future

Specialized computational chemistry packages have permanently reshaped the landscape of chemical and materials science by providing tools to support and guide experimental efforts and for the prediction of atomistic and electronic properties. In this regard, electronic structure packages have played a special role by using first-principle-driven methodologies to model complex chemical and materials processes. Over the past few decades, the rapid development of computing technologies and the tremendous increase in computational power have offered a unique chance to study complex transformations using sophisticated and predictive many-body techniques that describe correlated behavior of electrons in molecular and condensed phase systems at different levels of theory. In enabling these simulations, novel parallel algorithms have been able to take advantage of computational resources to address the polynomial scaling of electronic structure methods. In this paper, we briefly review the NWChem computational chemistry suite, including its history, design principles, parallel tools, current capabilities, outreach, and outlook.

A Benchtop Method for Appending Protic Functional Groups to N-Heterocyclic Carbene Protected Gold Nanoparticles

The remarkable resilience of N-heterocyclic carbene (NHC) gold bonds has quickly made NHCs the ligand of choice when functionalizing gold surfaces. Despite rapid progress using deposition from free or CO₂ -protected NHCs, synthetic challenges hinder the functionalization of NHC surfaces with protic functional groups, such as alcohols and amines, particularly on larger nanoparticles. Here, we synthesize NHC-functionalized gold surfaces from gold(I) NHC complexes and aqueous nanoparticles without the need for additional reagents, enabling otherwise difficult functional groups to be appended to the carbene. The resilience of the NHC-Au bond allows for multi-step post-synthetic modification. Beginning with the nitro-NHC, we form an amine-NHC terminated surface, which further undergoes amide coupling with carboxylic acids. The simplicity of this approach, its compatibility with aqueous nanoparticle solutions, and its ability to yield protic functionality, greatly expands the potential of NHC-functionalized noble metal surfaces.

The effect of breast cancer on work participation in different sectors. A Danish registry based study

Background

A breast cancer diagnosis affects an individual’s affiliation to the labor market, but whether the effect of breast cancer variates in different sectors in a Danish setting has not been examined. The present study investigated the effect of stage IA breast cancer (tumor&lt;20 mm and no lymph nodes involved in six sectors among Danish women being part of the work force. Stage IA breast cancer has a good prognosis, and it would be assumed that the majority have returned to work after 1 year.

Methods

This registry-based cohort study was based on data from linked Danish nationwide registries. We identified 5,543 women (aged 25-63 years) diagnosed with breast cancer (BC) stage IA (exposed) and 65.889 women without breast cancer (unexposed) and included women from the different sectors. We calculated a yearly Work Participation Score (WPS), defined as the proportion of weeks being self-supported during a year. We compared the means of WPS for exposed and unexposed women in six different sectors: 1) teaching, 2) childcare, 3) eldercare, 4) cleaning, 5) administration and 6) hospitality industry.

Results

BC had a negative effect on being self-supporting for women in all six sectors in all three years, although the effect declined. In the first year, the difference in WPS varied between 0.38 and 0.54. During the second year all BC patients had still significantly lower WPS with the largest difference in hospitality industry (0.65 (95% CI 0.50-0.80) for exposed women and 0.86 (95% CI 0.83-0.88) for unexposed women). In the third year, the effect further declined although WPS was still significantly lower for most sectors with the biggest difference in the cleaning sector.

Conclusions

A stage IA BC diagnosis had a negative effect on being self-supportive after 2 and 3 years among women in all six sectors, although the difference was largest among cleaning workers. This may indicate, that individual follow-up in relation to work participation is necessary.

Key messages

Although breast cancer stage IA has a good prognosis, it still affects being self-supporting after three years. A diagnosis of breast cancer affects the affiliation to the labour market, but the effect differs according to different sectors.

Revascularization after angiogenesis inhibition favors new sprouting over abandoned vessel reuse

Inhibiting pathologic angiogenesis can halt disease progression, but such inhibition may offer only a temporary benefit, followed by tissue revascularization after treatment stoppage. This revascularization, however, occurs by largely unknown phenotypic changes in pathologic vessels. To investigate the dynamics of vessel reconfiguration during revascularization, we developed a model of reversible murine corneal angiogenesis permitting longitudinal examination of the same vasculature. Following 30 days of angiogenesis inhibition, two types of vascular structure were evident: partially regressed persistent vessels that were degenerate and barely functional, and fully regressed, non-functional empty basement membrane sleeves (ebms). While persistent vessels maintained a limited flow and retained collagen IV+ basement membrane, CD31+ endothelial cells (EC), and α-SMA+ pericytes, ebms were acellular and expressed only collagen IV. Upon terminating angiogenesis inhibition, transmission electron microscopy and live imaging revealed that revascularization ensued by a rapid reversal of EC degeneracy in persistent vessels, facilitating their phenotypic normalization, vasodilation, increased flow, and subsequent new angiogenic sprouting. Conversely, ebms were irreversibly sealed from the circulation by excess collagen IV deposition that inhibited EC migration and prevented their reuse. Fully and partially regressed vessels therefore have opposing roles during revascularization, where fully regressed vessels inhibit new sprouting while partially regressed persistent vessels rapidly reactivate and serve as the source of continued pathologic angiogenesis.

Measuring Local Electric Fields and Local Charge Densities at Electrode Surfaces Using Graphene-Enhanced Raman Spectroscopy (GERS)-Based Stark-Shifts

We report spectroscopic measurements of the local electric fields and local charge densities at electrode surfaces using graphene-enhanced Raman spectroscopy (GERS) based on the Stark-shifts of surface-bound molecules and the G band frequency shift in graphene. Here, monolayer graphene is used as the working electrode in a three-terminal potentiostat while Raman spectra are collected in situ under applied electrochemical potentials using a water immersion lens. First, a thin layer (1 Å) of copper(II) phthalocyanine (CuPc) molecules are deposited on monolayer graphene by thermal evaporation. GERS spectra are then taken in an aqueous solution as a function of the applied electrochemical potential. The shifts in vibrational frequencies of the graphene G band and CuPc are obtained simultaneously and correlated. The upshifts in the G band Raman mode are used to determine the free carrier density in the graphene sheet under these applied potentials. Of the three dominant peaks in the Raman spectra of CuPc (i.e., 1531, 1450, and 1340 cm^-1), only the 1531 cm^-1 peak exhibits Stark-shifts and can, thus, be used to report the local electric field strength at the electrode surface under electrochemical working conditions. Between applied electrochemical potentials from -0.8 V to 0.8 V vs NHE, the free carrier density in the graphene electrode spans a range from -4 × 10¹² cm^-2 to 2 × 10¹² cm^-2. Corresponding Stark-shifts in the CuPc peak around 1531 cm^-1 are observed up to 1.0 cm^-1 over a range of electric field strengths between -3.78 × 10⁶ and 1.85 × 10⁶ V/cm. Slightly larger Stark-shifts are observed in a 1 M KCl solution, compared to those observed in DI water, as expected based on the higher ion concentration of the electrolyte. Based on our data, we determine the Stark shift tuning rate to be 0.178 cm^-1/ (10⁶ V/cm), which is relatively small due to the planar nature of the CuPc molecule, which largely lies perpendicular to the electric field at this electrode surface. Computational simulations using density functional theory (DFT) predict similar Stark shifts and provide a detailed atomistic picture of the electric field-induced perturbations to the surface-bound CuPc molecules.

Resolving Molecular Structures with High-Resolution Tip-Enhanced Raman Scattering Images

Vibrational modes of a single molecule can be visualized by tip-enhanced Raman spectroscopy with atomic resolution. However, the exact vibrations associated with these Raman scattering images are still in debate due to the lack of theoretical interpretation. In this work, we systematically study the Raman scattering images of a single Co(II)-tetraphenylporphyrin molecule. The stable structure whose Raman scattering images consistently match experimental results is discovered. Furthermore, we elucidate the effects of near-field localizations and field gradient on the resolution in Raman scattering images. The approach of locally integrated Raman polarizability density employed in this work provides an intuitive explanation of the origin of the experimental Raman scattering images.

Cytotoxic unsaturated electrophilic compounds commonly target the ubiquitin proteasome system

A large number of natural products have been advocated as anticancer agents. Many of these compounds contain functional groups characterized by chemical reactivity. It is not clear whether distinct mechanisms of action can be attributed to such compounds. We used a chemical library screening approach to demonstrate that a substantial fraction (~20%) of cytotoxic synthetic compounds containing Michael acceptor groups inhibit proteasome substrate processing and induce a cellular response characteristic of proteasome inhibition. Biochemical and structural analyses showed binding to and inhibition of proteasome-associated cysteine deubiquitinases, in particular ubiquitin specific peptidase 14 (USP14). The results suggested that compounds bind to a crevice close to the USP14 active site with modest affinity, followed by covalent binding. A subset of compounds was identified where cell death induction was closely associated with proteasome inhibition and that showed significant antineoplastic activity in a zebrafish embryo model. These findings suggest that proteasome inhibition is a relatively common mode of action by cytotoxic compounds containing Michael acceptor groups and help to explain previous reports on the antineoplastic effects of natural products containing such functional groups.

The Critical Role of Dysregulated RhoB Signaling Pathway in Radioresistance of Colorectal Cancer

PURPOSE

To explore whether the Rho protein is involved in the radioresistance of colorectal cancer and investigate the underlying mechanisms.

METHODS AND MATERIALS

Rho GTPase expression was measured after radiation treatment in colon cancer cells. RhoB knockout cell lines were established using the CRISPR/Cas9 system. In vitro assays and zebrafish embryos were used for analyzing radiosensitivity and invasive ability. Mass cytometry was used to detect RhoB downstream signaling factors. RhoB and Forkhead box M1 (FOXM1) expression were detected by immunohistochemistry in rectal cancer patients who participated in a radiation therapy trial.

RESULTS

RhoB expression was related to radiation resistance. Complete depletion of the RhoB protein increased radiosensitivity and impaired radiation-enhanced metastatic potential in vitro and in zebrafish models. Probing signaling using mass cytometry-based single-cell analysis showed that the Akt phosphorylation level was inhibited by RhoB depletion after radiation. FOXM1 was downregulated in RhoB knockout cells, and the inhibition of FOXM1 led to lower survival rates and attenuated migration and invasion abilities of the cells after radiation. In the patients who underwent radiation therapy, RhoB overexpression was related to high FOXM1, late Tumor, Node, Metastasis stage, high distant recurrence, and poor survival independent of other clinical factors.

CONCLUSIONS

RhoB plays a critical role in radioresistance of colorectal cancer through Akt and FOXM1 pathways.

MicroRNAs in the cornea: Role and implications for treatment of corneal neovascularization

With no safe and efficient approved therapy available for treating corneal neovascularization, the search for alternative and effective treatments is of great importance. Since the discovery of miRNAs as key regulators of gene expression, knowledge of their function in the eye has expanded continuously, facilitated by high throughput genomic tools such as microarrays and RNA sequencing. Recently, reports have emerged implicating miRNAs in pathological and developmental angiogenesis. This has led to the idea of targeting these regulatory molecules as a therapeutic approach for treating corneal neovascularization. With the growing volume of data generated from high throughput tools applied to study corneal neovascularization, we provide here a focused review of the known miRNAs related to corneal neovascularization, while presenting new experimental data and insights for future research and therapy development.

Experimental Observation of Proton Bunch Modulation in a Plasma at Varying Plasma Densities

We give direct experimental evidence for the observation of the full transverse self-modulation of a long, relativistic proton bunch propagating through a dense plasma. The bunch exits the plasma with a periodic density modulation resulting from radial wakefield effects. We show that the modulation is seeded by a relativistic ionization front created using an intense laser pulse copropagating with the proton bunch. The modulation extends over the length of the proton bunch following the seed point. By varying the plasma density over one order of magnitude, we show that the modulation frequency scales with the expected dependence on the plasma density, i.e., it is equal to the plasma frequency, as expected from theory.

Experimental Observation of Plasma Wakefield Growth Driven by the Seeded Self-Modulation of a Proton Bunch

We measure the effects of transverse wakefields driven by a relativistic proton bunch in plasma with densities of 2.1×10^{14} and 7.7×10^{14}  electrons/cm^{3}. We show that these wakefields periodically defocus the proton bunch itself, consistently with the development of the seeded self-modulation process. We show that the defocusing increases both along the bunch and along the plasma by using time resolved and time-integrated measurements of the proton bunch transverse distribution. We evaluate the transverse wakefield amplitudes and show that they exceed their seed value (<15  MV/m) and reach over 300  MV/m. All these results confirm the development of the seeded self-modulation process, a necessary condition for external injection of low energy and acceleration of electrons to multi-GeV energy levels.