Identification of Chemicals That Abrogate Folate-Dependent Inhibition of Starch Accumulation in Non-Photosynthetic Plastids of Arabidopsis

Folate, also known as vitamin B9, is an essential cofactor for a variety of enzymes and plays a crucial role in many biological processes. We previously reported that plastidial folate prevents starch biosynthesis triggered by the influx of sugar into non-starch-accumulating plastids, such as etioplasts, and chloroplasts under darkness; hence the loss of plastidial folate induces the accumulation of starch in plastids. To understand the molecular mechanism underlying this phenomenon, we screened our in-house chemical library and searched their derivatives to identify chemicals capable of inducing starch accumulation in etioplasts. The results revealed four chemicals, compounds #120 and #375 and their derivatives, compounds #120d and #375d, respectively. The derivative compounds induced starch accumulation in etioplasts and suppressed hypocotyl elongation in dark-grown Arabidopsis seedlings. They also inhibited the post-germinative growth of seedlings under illumination. All four chemicals contained the sulfonamide group as a consensus structure. The sulfonamide group is also found in sulfa drugs, which exhibit antifolate activity, and in sulfonylurea herbicides. Further analyses revealed that compound #375d induces starch accumulation by inhibiting folate biosynthesis. By contrast, compound #120d neither inhibited folate biosynthesis nor exhibited the herbicide activity. Protein and metabolite analyses suggest that compound #120d abrogates folate-dependent inhibition of starch accumulation in etioplasts by enhancing starch biosynthesis.

Acceleration of Protein Degradation by 20S Proteasome-Binding Peptides Generated by In Vitro Artificial Evolution

Although the 20S core particle (CP) of the proteasome is an important component of the 26S holoenzyme, the stand-alone 20S CP acts directly on intrinsically disordered and oxidized/damaged proteins to degrade them in a ubiquitin-independent manner. It has been postulated that some structural features of substrate proteins are recognized by the 20S CP to promote substrate uptake, but the mechanism of substrate recognition has not been fully elucidated. In this study, we screened peptides that bind to the 20S CP from a random eight-residue pool of amino acid sequences using complementary DNA display an in vitro molecular evolution technique. The identified 20S CP-binding amino acid sequence was chemically synthesized and its effects on the 20S CP were investigated. The 20S CP-binding peptide stimulated the proteolytic activity of the inactive form of 20S CP. The peptide bound directly to one of the α-subunits, opening a gate for substrate entry on the α-ring. Furthermore, the attachment of this peptide sequence to α-synuclein enhanced its degradation by the 20S CP in vitro. In addition to these results, docking simulations indicated that this peptide binds to the top surface of the α-ring. These peptides could function as a key to control the opening of the α-ring gate.

Chemotherapy after nivolumab for advanced gastric cancer (REVIVE): a prospective observational study

BACKGROUND

Nivolumab therapy is a standard-of-care treatment for heavily pretreated patients with advanced gastric cancer (AGC). Previous studies have reported improvement in the objective response rate to chemotherapy after nivolumab therapy for other types of cancer. This study evaluated the efficacy and safety of chemotherapy after nivolumab therapy in AGC.

PATIENTS AND METHODS

We conducted a prospective, multicenter, observational study in pretreated patients with nivolumab-refractory or -intolerant AGC. Patients received irinotecan, oxaliplatin-containing regimens, or trifluridine/tipiracil. The primary endpoint was overall survival.

RESULTS

A total of 199 patients were included (median age: 69 years; male: 70%; female: 30%). Median overall survival and progression-free survival were 7.5 months [95% confidence interval (CI): 6.7-9.7 months] and 2.9 months (95% CI: 2.2-3.5 months), respectively. Objective response and disease control rates were 16.8% (95% CI: 11.6% to 23.6%) and 18.9% (95% CI: 38.9% to 54.6%), respectively. A prognostic index using alkaline phosphatase and the Glasgow Prognostic Score was generated to classify patients into three risk groups (good, moderate, and poor). The hazard ratios of the moderate and poor groups to the good group were 1.88 (95% CI: 1.22-2.92) and 3.29 (95% CI: 1.92-5.63), respectively. At the initiation of chemotherapy, 42 patients had experienced immune-related adverse events due to prior nivolumab therapy. The most common grade 3-4 adverse events were neutropenia (7.5%), anemia (8.0%), and anorexia (7.5%).

CONCLUSIONS

The administration of cytotoxic chemotherapy after nivolumab therapy may give rise to a synergistic antitumor effect in AGC. Further investigation is warranted to confirm these findings.

An Enzyme-Linked Immunosorbent Assay to Quantify Poly (ADP-Ribose) Level In Vivo

PolyADP-ribosylation is a posttranslational modification of proteins that results from enzymatic synthesis of poly(ADP-ribose) with NAD⁺ as the substrate. A unique characteristic of polyADP-ribosylation is that the poly(ADP-ribose) chain can have 200 or more ADP-ribose residues in branched patterns, and the presence and variety of these chains can have substantive effects on protein function. To understand how polyADP-ribosylation affects biological processes, it is important to know the physiological level of poly(ADP-ribose) in cells. Under normal cell physiological conditions and in the absence of any exogenous DNA damaging agents, we found that the concentration of poly(ADP-ribose) in HeLa cells is approximately 0.04 pmol (25 pg)/10⁶ cells, as measured with a double-antibody sandwich, enzyme-linked immunosorbent assay protocol that avoids artificial activation of PARP1 during cell lysis. Notably, this system demonstrated that the poly(ADP-ribose) level peaks in S phase and that the average cellular turnover of a single poly(ADP-ribose) is less than 40 s.

Improvement in angina pectoris after percutaneous coronary interventions in focal and diffuse coronary artery disease

Objective

To investigate the effect of PCI on patient-reported outcomes in focal and diffuse coronary artery disease (CAD) as defined by the pullback pressure gradient (PPG).

Background

Improvements in fractional flow reserve (FFR) following PCI are associated with freedom from angina. CAD patterns influence the FFR change after stenting. Therefore, CAD patterns might be essential to assess the likelihood of PCI success in terms of angina relief.

Methods

This is a sub-analysis of the TARGET-FFR randomized clinical trial (NCT03259815). The 7-item Seattle Angina Questionnaire (SAQ-7) and EuroQol five-level EQ-5D questionnaire (EQ-5D-5L) were administered at baseline and three months after PCI. The PPG index was calculated from manual pre-PCI FFR pullbacks and the median PPG value was used to define focal and diffuse CAD.

Results

103 patients (51 with focal and 52 with diffuse disease) were analyzed. There were no differences in baseline characteristics between patients with focal and diffuse CAD. Patients with focal disease had larger increases in FFR with PCI than those with diffuse disease (0.30±0.14 units vs 0.19±0.12 units, p<0.001). Patients who underwent PCI to focal CAD had significantly higher SAQ-7 summary scores at follow-up compared to those with diffuse CAD (87.1±20.3 vs. 75.6±24.4, mean difference 11.5 [95% CI 2.8 to 20.3], p=0.01). Following PCI, residual angina was present in 39.8% of all patients but was significantly lower among those with treated focal CAD (27.5% vs 51.9%, p-value=0.020).

Conclusion

Persistent angina after PCI was almost twice as common in patients with diffuse CAD as defined by the pre-PCI PPG. Patients with focal disease reported greater improvement in angina and quality of life with PCI. The likelihood of successful angina relief from PCI can be predicted by the baseline pattern of CAD.

Funding Acknowledgement

Type of funding sources: None.

Structure and Function of Potential Glycosylation Sites of Dynactin-Associated Protein dynAP

Overexpression of human dynactin-associated protein (dynAP) transforms NIH3T3 cells. DynAP is a single-pass transmembrane protein with a carboxy-terminal region (amino acids 135-210) exposed to the outside of the cell possessing one potential N-glycosylation site (position 143) and a distal C-terminal region (residues 173-210) harboring a Thr/Ser-rich (T/S) cluster that may be O-glycosylated. In SDS-PAGE, dynAP migrates anomalously at ~ 45 kDa, much larger than expected (22.5 kDa) based on the amino acid composition. Using dynAP mutants, we herein showed that the T/S cluster region is responsible for the anomalous migration. The T/S cluster region is required for transport to the cytoplasmic membrane and cell transformation. We produced and purified the extracellular fragment (dynAP135-210) in secreted form and analyzed the attached glycans. Asn143 displayed complex-type glycosylation, suggesting that oligosaccharide transferase may recognize the NXT/S sequon in the secretory form, but not clearly in full-length dynAP. Core I-type O-glycosylation (Gal-GalNAc) was observed, but the mass spectrometry signal was weak, clearly indicating that further studies are needed to elucidate modifications in this region.

Expression and cell transformation activity of dynactin-associated protein isoforms

Overexpression of human dynactin-associated protein isoform a (dynAPa) transforms NIH3T3 cells. DynAPa is a single-pass transmembrane protein with a carboxy-terminal region exposed to the outside of cells. According to the NCBI RefSeq database, there may be two other splicing variants of the encoding gene (dynAPb and c). DynAPa and c differ in some amino-terminal residues (NH₂ -MVA in dynAPa and NH₂ -MEYQLL in dynAPc). DynAPb has the same amino-terminal residues as dynAPc, but lacks 55 residues in the intracellular region. All three isoforms have the same carboxy-terminal region, including the transmembrane domain. Expression of mRNAs of three splicing variants was found in human cancer cell lines ACHN and Caki-1. The subcellular localization and in vitro cell transformation ability of the three isoforms were examined using NIH3T3 cells overexpressing each respective isoform. All isoforms were found to be localized to the Golgi apparatus and plasma membrane, where the carboxy-terminal region was exposed to the outside of cells. Cell transformation was tested using focus formation due to loss of contact inhibition of cell proliferation, and colony formation was examined on soft agar and spheroid formation in ultralow U-bottomed wells. DynAPa robustly formed foci and colonies on soft agar and spheroid, whereas these abilities were considerably decreased for dynAPb and completely lost in dynAPc. These findings warrant dissection studies to identify the dynAP domain that is required for cell transformation.

Endoscopic repair of atrial functional mitral regurgitation in heart failure: long-term effects

Introduction

In patients with heart failure and preserved ejection fraction (HFpEF), even mild atrial functional mitral regurgitation (AFMR) has been associated with poor outcome.

Objective

To describe long-term effects of endoscopic mitral valve (MV) repair on outcome in patients with HFpEF and AFMR.

Methods

The study population consisted of consecutive patients with HFpEF (LVEF ≥50%, H2FPEF score ≥5) and AFMR, who underwent isolated, minimally invasive (endoscopic), MV repair (MVRepair group) (n=131) or remained on standard of care (StanCare group) (n=139). Patients with coronary artery disease or organic MR were excluded. Patients were matched using inverse probability of treatment weighting. Primary objective was all-cause mortality or HFpEF readmissions.

Results

The median follow up was 5.03 years (IQR 2.6–7.9 years). In the MVRepair group, the perioperative, 30-day, 1- and 5-year mortality was 0, 1% and 12%, respectively. Additional 13 (10%) patients were readmitted for worsening HFpEF, while 2 (1%) individuals underwent redo MV surgery for recurrent MR. MVRepair compared with StanCare showed 21–29% (SE 6–8%) and 19–26% (SE 6–8%) absolute risk reduction of all-cause mortality and HFpEF readmissions, respectively (all p<0.05). MVRepair emerged as the strongest independent predictor of all-cause mortality (HR 0.16, 95% CI 0.07–0.34, p<0.001) and HFpEF readmissions (HR 0.21, 95% CI 0.09–0.51, p<0.001). At 5-year follow-up, in the MVRepair group, a total of 88% were alive and 80% were alive without readmission for HFpEF.

Conclusions

Endoscopic MV repair is associated with low perioperative mortality, high long-term efficacy and appears to improve clinical outcome in patients with AFMR and HFpEF.

Mortality and readmission for HF

Funding Acknowledgement

Type of funding source: None

Hyperemic hemodynamic characteristics of serial coronary lesions assessed by pressure pullbacks gradients (PPG) index

Introduction

The evaluation of functional significance in serial coronary lesions is crucial for achieving optimal clinical outcomes. In this setting, fractional flow reserve (FFR) measurements with pullback pressure recording can be helpful in assessing lesion functional significance.

Purpose

To describe the functional characteristics of angiography-defined serial coronary lesions using FFR-derived motorised pullback tracings, and to describe the Pullback Pressure Gradients (PPG) index - in these lesions.

Methods

Prospective, multicentre study with independent core laboratory analysis. Patients undergoing coronary angiography due to stable angina were enrolled. Serial lesions were defined angiographically as the presence of 2 or more narrowings with visual diameter stenosis >50% separated at least by 3 times the reference vessel diameter in the same coronary vessel. Continuous IV adenosine-FFR measurements were obtained using a motorised device at a speed of 1 mm/s. Pullback curves were assessed to determine the presence of focal step-ups (FFR >0.05 units over 20 mm). In addition, the PPGindex was computed for all vessels. PPGindex values close to 0 define functional diffuse disease whereas values close to 1 define focal disease.

Results

From a total of 159 vessels (117 patients), 25 vessels were adjudicated as presenting serial lesions (mean PPGindex 0.48±0.17, range 0.26–0.87). Two focal pressure step-ups were observed in 40% of the cases (n=10; mean PPGindex 0.59±0.17), whereas 8% of the vessels presented a progressive pressure losses (n=2; mean PPGindex 0.27±0.01). In the remaining 52% of the cases, a single pressure step-up was recorded (n=13; mean PPGindex 0.44±0.12; ANOVA p-value = 0.01). The PPGindex independently predicted the presence of two focal pressure step ups.

Conclusion

Hyperemic FFR curves in tandem stenoses revealed high prevalence of functional diffuse CAD. Two pressure step-ups occurred in less than half of the vessels. High PPG-Index identified vessels with two focal pressure drops. FFR tracings and the PPGindex provide a more objective CAD evaluation, which can lead to changes in the therapeutic approach.

Funding Acknowledgement

Type of funding source: None

P2721FFRct analysis for screening of obstructive coronary artery disease: a propensity score adjusted study

Background

Guidelines recommend functional assessment in stable coronary artery disease (CAD) to guide further treatment. Computed tomography fractional flow reserve (FFRCT) has been proposed for non-invasive assessment of stable CAD. A cutoff value of FFRCT ≥0.8 has been shown cost-effective, and allowing to avoid inappropriate invasive coronary angiography (ICA). However, no results from real-life hospital registries have been reported yet.

Purpose

We aimed to compare the impact of FFRCT with conventional coronary CT angiography (CTA) for detecting obstructive CAD in the daily practice of a tertiary referral hospital.

Methods

Patients referred to CTA for suspected CAD between 2013 and 2017 were included. FFRCT analysis was introduced in 2015 and performed at the discretion of the radiologist by Heartflow Inc. FFRCT was considered abnormal if FFR was <0.8 in at least one of 3 main vessels. Obstructive CAD was defined on both CTA and ICA by the presence of a stenosis ≥50% in at least one of 3 main vessels, or an invasive FFR<0.8. Propension to perform a FFRCT was modeled, based on gender, cardiovascular risk factors, completion of stress test and echocardiography and presence of a lesion of more than 50% stenosis on CTA. A logistic regression adjusted for the propensity score was then performed on the use of ICA, the presence of significant CAD on ICA and revascularization rate either by PCI or CABG.

Results

2906 patients (50% of male, 56±12) were included in this registry. Diabetes, hypertension, dyslipidemia and smoking were present in respectively 12.3, 30.5, 27.5 and 9% of patients. A stress ECG and a transthoracic echo were obtained in respectively 37.1 and 49% of patients. FFRCT was performed in 757 (26%) and was abnormal in 323 (42.7%) of the patients. An ICA was performed in 622 (21.4%) patients and was abnormal in 292 (46.9%). After propensity score weighting, FFRCT was associated with an increase in ICA (OR=1.58, 95% CI: 1.23–2.02, p<0.01). There were no significant changes regarding ICA showing obstructive CAD with FFRCT (OR=1.13, 95% CI: 0.78–1.66, p=0.5) but a trend towards an increase of revascularization (OR=1.48, 95% CI: 0.98–2.24, p=0.06). In patient undergoing an ICA, a FFRCT ≥0.8 was decreasing the presence of significant CAD (OR=0.27, 95% CI: 0.16–0.48, p<0.001), whereas a FFRCT <0.8 increased the rate of revascularization (OR=24.7, 95% CI: 12.3–49.7, p<0.001).

Conclusion

These real life data showed that, adding FFRCT to conventional CTA, and interpreting only the numerical values of FFRCT, would increase the use of ICA in patients suspected of CAD. A trend towards an increase in revascularization was also observed. Therefore, another index than the minimal FFRCT should be used to improve discrimination regarding the presence of obstructive CAD. However, normal values of FFRCT were strong predictors of the absence of significant CAD, and abnormal values of FFRCT for the need of a revascularization.

279Clinical outcome after coronary bifurcation stenting: a systematic review and network meta-Analysis of PCI bifurcation techniques comprising 5572 patients

Background

The optimal PCI technique for bifurcation lesions remains a matter of debate. Several RCT have compared different bifurcation PCI techniques. Provisional stenting has been recommended as the default technique for most bifurcation lesions. However, emerging data suggests that double-kissing crush technique can be considered in true left main bifurcation lesions and has been endorsed by the European Society of Cardiology Guidelines.

Purpose

To compare the clinical outcome between different bifurcation PCI techniques.

Methods

We searched MEDLINE for randomized clinical trials (RCT) comparing PCI bifurcation techniques for coronary bifurcation lesions. Outcomes of interest were major adverse cardiovascular events (MACE) defined as the composite of cardiac death, myocardial infarction (MI) and target vessel or lesion revascularization (TVR/TLR), and the individual components of MACE. Stent thrombosis was assessed as defined by the ARC. Stratification based on left-main or distal bifurcations was performed. We evaluated the studies' risk of bias in accordance to the Cochrane Handbook for Systematic Reviews of Interventions, and certainty of evidence using the Grading of Recommendations Assessment, Development and Evaluation framework. We estimated summary odds ratios (ORs) using pairwise and Bayesian network meta-analysis.

Results

We identified 263 studies and of these included 19 RCT including 5572 patients treated with 5 bifurcation PCI techniques namely provisional stenting, systematic T-stenting, crush, culotte and double-kissing crush. Median follow-up was 12 months (IQR 8 to 36). When all bifurcation lesions were combined, double-kissing crush technique reduced the occurrence of MACE (OR 0.42; CrI 0.28 to 0.61) compared to provisional stenting. This difference was driven by a reduction in TVR/TLR (OR 0.39; CrI 0.25 to 0.65). No differences were found in cardiac death, MI or stent thrombosis among analyzed PCI techniques. No differences in MACE were observed between provisional stenting, systematic T-stenting, crush. In distal bifurcations (n=17 studies, 4634 patients), double-kissing crush also showed to reduce MACE (OR 0.48; CrI 0.29 to 0.67 vs. Provisional). In left-main bifurcations (n=3 studies, 938 patients) no differences in MACE were found between PCI techniques.

Conclusions

In this network meta-analysis, PCI bifurcation techniques were similar with respect to the occurrence of cardiac death, myocardial infarction and stent thrombosis. When all coronary bifurcations were combined, an advantage of double-kissing crush was observed in terms of MACE driven by lower rate of repeated revascularization. Further studies are required to define the best PCI bifurcation technique for left main coronary artery disease.

P854Physiological patterns of coronary artery disease

Background

Randomised controlled trials have confirmed the clinical benefit of invasive functional assessment to guide clinical decision making about myocardial revascularisation in patients with stable coronary artery disease. Treatment decision is based on one FFR value which provides a vessel-level metric as a surrogate of myocardial ischaemia. Also, the distribution of epicardial conductance can be evaluated using an FFR pullback manoeuvre.

Purpose

The objective of the present study is to characterise the physiological patterns of CAD using motorised coronary pressure pullbacks during continuous hyperaemia in patients with stable coronary artery disease.

Methods

Prospective, multicentre study of patients undergoing clinically-indicated coronary angiography. A pullback device, adapted to grip the coronary pressure wire, was set at a speed of 1 mm/sec. The pattern of CAD was adjudicated by visual inspection of the FFR pullback curves as focal, diffuse, or a combination of both mechanisms. Also, a quantitative classification of the physiological pattern of CAD was performed based on (1) the functional contribution of the epicardial lesion in relation to the total vessel FFR (Δlesion FFR/Δvessel FFR) and (2) the length (mm) of epicardial coronary segments with FFR drops in relation to the total vessel length. The combination of these two ratios, namely, lesion-related pressure drops (%FFR-lesion), and the extent of functional disease, resulted in the functional outcomes index (FOI), a metric that represents the pattern of CAD (i.e. focality or diffuseness) based on coronary physiology. Agreement on CAD patterns and between observers was assessed using Fleiss' Kappa. Analysis of variance (ANOVA) was used to compared quantitative variables. Correlation between variables was assessed by the Pearson moment coefficient.

Results

One hundred and fifty-eight vessels were included; 984,813 FFR values were used to generate the FFR pullback curves. Using motorised FFR pullbacks, 34% of the vessel disease patterns (i.e. focal, diffuse or combined) were reclassified compared to conventional angiography. The mean contribution of the angiographic lesions to the distal FFR (%FFR-lesion) was 61.7±25% whereas vessel length with the physiological disease was 59.8±21% of the total vessel length. The mean FOI was 0.61±0.17, and differentiated focal from diffuse CAD in terms of %FFR-lesion (p<0.001) and physiological extent of CAD (p<0.001).

Conclusion

Coronary angiography was inaccurate to assess the patterns of CAD. The inclusion of the functional component reclassified 34% of the vessel disease patterns (i.e. focal, diffuse or combined). A new metric, the FOI, based on the functional impact of anatomical lesions and the extent of physiological disease, discriminated focal from diffuse CAD. Further clinical trials are required to evaluate the usefulness of FOI for clinical decision making and outcomes.

P855Evaluation of epicardial coronary resistance using computed tomography angiography

Background

A Fractional flow reserve (FFR) pullback allows assessing the distribution of pressure loss along the vessel. FFR derived from CT (FFRCT) provides a virtual pullback curve that may also aid in the assessment of epicardial coronary resistance in the non-invasive setting.

Purpose

The present study aims to determine the accuracy of the virtual FFRCT pullback curve using a motorized invasive FFR pullback as reference in patients with stable coronary artery disease.

Methods

This is a single centre, prospective study of patients with stable coronary artery disease in whom FFRCT was performed as standard of care for non-invasive assessment. Patients referred to coronary angiography with clinically indicated invasive FFR measurement were included. FFRCT and invasive FFR values were extracted from coronary vessels every 1 mm to generate pullback curves. Invasive FFR pullbacks were acquired using a dedicated device at a speed of 1 mm/s. The area under the pullback curve (AUPC), defined as the sum of areas under the FFR pullback curve, was compared between FFRCT and invasive FFR pullbacks. Lesions were defined based on invasive angiography. FFR gradients in lesions and non-obstructive segments were defined as the difference between FFR values at the proximal and distal edge of the segments. FFR vessel gradient was defined as the difference between the most distal FFR value and the FFR at the ostium of the vessel. Mixed effect model was used to account for the correlation of FFR values within vessels. The agreement between FFRCT and FFR gradients was assessed using the Passing Bablok regression analysis and Bland-Altman methods at the vessel, lesion and non-obstructive level.

Results

A total of 3172 matched FFRCT and FFR values were obtained in 24 vessels. The correlation coefficient between FFRCT and FFR was 0.76 (95% CI 0.75 to 0.78; p<0.001). The mean difference between the FFRCT and invasive FFR pullback values was 0.07 (LOA −0.11 to 0.24). AUPC was similar between FFRCT and invasive FFR (79.0±16.1 vs. 85.3±16.4, p=0.097); the mean slope of FFRCT pullback curve was steeper compared to invasive FFR (p<0.001). The mean difference in lesion gradient was −0.07 (LOA −0.26 to 0.13) and −0.01 (LOA −0.06 to 0.05) in non-obstructive segments. There were no systematic or proportional differences between FFRCT and FFR gradients either in lesion or non-obstructive segments); however, vessel gradients were overestimated by FFRCT with a bias of −0.12 (LOA −0.35 to 0.12) driven by a higher mean difference in lesion gradients (−0.07; 95% CI −0.26 to 0.13).

Conclusions

The evaluation of epicardial coronary resistance using coronary CT angiography with FFRCT was feasible. FFRCT pullbacks were accurate in the assessment of lesion and non-obstructive gradients. FFRCT can identify the physiological pattern of coronary artery disease in the non-invasive setting.

Tongue surface model can predict radiation tongue mucositis due to intensity-modulated radiation therapy for head and neck cancer

Acute radiation tongue mucositis has a profound effect on talking and eating. We examined whether the dose-volume histogram obtained from the tongue surface model correlates with mucositis severity, and whether it is useful for predicting acute radiation tongue mucositis in patients with head and neck cancer treated with intensity-modulated radiation therapy. Thirty-six patients who received intensity-modulated radiation therapy for head and neck cancer were analysed for acute radiation tongue mucositis according to the Common Terminology Criteria for Adverse Events, version 4.0, as well as the Radiation Therapy Oncology Group scoring systems. The corresponding high-dose locations in anatomical sub-regions in the tongue surface model and the development of high-grade acute radiation tongue mucositis were compared. The mucositis sites coincided with the high-dose anatomical sub-regions in the tongue surface model. There was a clear dose-response relationship between the mean dose to the tongue and the acute radiation tongue mucositis Radiation Therapy Oncology Group grade. According to the dose-volume histogram, patients receiving 16.0-73.0 Gy to the tongue were susceptible to grade 2-3 toxicity. The tongue surface model can predict the site and severity of acute radiation tongue mucositis. In future, radiation treatment plans ccould be optimized using this model.

Ecology of the cardiovascular system: Part II - A focus on non-air related pollutants

An integrated exposomic view of the relation between environment and cardiovascular health should consider the effects of both air and non-air related environmental stressors. Cardiovascular impacts of ambient air temperature, indoor and outdoor air pollution were recently reviewed. We aim, in this second part, to address the cardiovascular effects of noise, food pollutants, radiation, and some other emerging environmental factors. Road traffic noise exposure is associated with increased risk of premature arteriosclerosis, coronary artery disease, and stroke. Numerous studies report an increased prevalence of hypertension in people exposed to noise, especially while sleeping. Sleep disturbances generated by nocturnal noise are followed by a neuroendocrine stress response. Some oxidative and inflammatory endothelial reactions are observed during experimental session of noise exposure. Moreover, throughout the alimentation, the cardiovascular system is exposed to persistent organic pollutants (POPs) as dioxins or pesticides, and plastic associated chemicals (PACs), such as bisphenol A. Epidemiological studies show positive associations of exposures to POPs and PACs with diabetes, arteriosclerosis and cardiovascular disease incidence. POPs and PACS share some abilities to interact with nuclear receptors activating different pathways leading to oxidative stress, insulin resistance and angiotensin potentiation. Regarding radiation, survivors of nuclear explosion have an excess risk of cardiovascular disease. Dose-effect relationships remain debated, but an increased cardiovascular risk at low dose of radiation exposure may be of concern. Some emerging environmental factors like electromagnetic fields, greenspace and light exposure may also require further attention. Non-air related environmental stressors also play an important role in the burden of cardiovascular disease. Specific methodologies should be developed to assess the interactions between air and non-air related pollutants.

Detection of rotavirus in clinical specimens using an immunosensor prototype based on the photon burst counting technique

In this study, a sensitive fluorescence sensor was developed for the detection of small, fluorescence-labeled particles dispersed in a solution. The prototype system comprises of a laser confocal optical system and a mechanical sample stage to detect photon bursting of fluorescence-labeled small particles in sample volumes less than 5 μL within 3 minutes. To examine the feasibility of the prototype system as a diagnostic tool, assemblages of rotavirus and fluorescence-labeled antibody were analyzed. The detection sensitivity for rotavirus was 1 × 10⁴ pfu/mL. Rotavirus in stool samples from patients with acute gastroenteritis was also detected. The advantages and disadvantages of this immunosensor with respect to ELISA and RT-PCR, the current gold standards for virus detection, are discussed.

Evaluation of phenylcyclopropylamine compounds by enzymatic assay of lysine-specific demethylase 2 in the presence of NPAC peptide

Lysine-specific demethylase 2 (LSD2) demethylates mono- and dimethylated Lys-4 of histone H3 (H3K4me1 and H3K4me2). NPAC protein is known to interact with LSD2 and promote its H3K4 demethylase activity. In this study, we established a demethylation assay system that utilizes recombinant LSD2 in the presence of a synthetic NPAC peptide. Several phenylcyclopropylamine (PCPA)-based inhibitors were examined for their LSD2 inhibitory activity in the LSD2 enzymatic assay with the NPAC peptide. The assay results showed that the PCPA derivatives, including NCD41, selectively inhibited LSD1 in preference to LSD2.

The Impact of c-Fos/Activator Protein-1 Inhibition on Allogeneic Pancreatic Islet Transplantation

Unpreventable allograft rejection is one of the main problems in pancreatic islet transplantation (PIT). Therefore, it is imperative to develop a more effective immunosuppressive strategy. The blockade of transcription factors has been a central part of T cell-depleting immunosuppressive therapies, as typified by the use of calcineurin inhibitors. The inhibition of activator protein-1 (AP-1) offers a novel strategy for immunosuppression in PIT, although to date, no reports on the effects of AP-1 inhibition are available. In this study, we investigated the immunosuppressive effects of T-5224, a c-Fos/AP-1-selective inhibitor, on murine T cells activated by αCD3+αCD28 mAbs. T-5224 inhibited proliferation, CD25 up-regulation, and the production of IL-2 and interferon-γ. In addition, T-5224 blocked the nuclear translocation of c-Fos/AP-1 in activated murine T cells. In BALB/c (H-2(d) )-to-C57BL/6J (H-2(b) ) mouse PIT, the 2-week administration of T-5224 prolonged survival of 600 islet allografts in a dose-dependent manner. When combined with a 2-week low-dose tacrolimus, the T-5224 treatment markedly prolonged allograft survival to over 300 days, while the efficacy was indeterminate when transplanted islet allograft mass was reduced to 300. We conclude that the c-Fos/AP-1 inhibition by T-5224 is a potentially attractive strategy for allogeneic PIT.

Human Dynactin-Associated Protein Transforms NIH3T3 Cells to Generate Highly Vascularized Tumors with Weak Cell-Cell Interaction

Human dynactin-associated protein (dynAP) is a transmembrane protein that promotes AktSer473 phosphorylation. Here, we report the oncogenic properties of dynAP. In contrast to control NIH3T3 cells expressing LacZ (NIH3T3LacZ), NIH3T3dynAP cells vigorously formed foci in two-dimensional culture, colonies on soft agar, and spheroids in anchorage-deficient three-dimensional culture. NIH3T3dynAP cells injected into nude mice produced tumors with abundant blood vessels and weak cell—cell contacts. Expression of dynAP elevated the level of rictor (an essential subunit of mTORC2) and promoted phosphorylation of FOXO3aSer253. FOXO3a is a transcriptional factor that stimulates expression of pro-apoptotic genes and phosphorylation of FOXO3a abrogates its function, resulting in promoted cell survival. Knockdown of rictor in NIH3T3dynAP cells reduced AktSer473 phosphorylation and formation of foci, colony in soft agar and spheroid, indicating that dynAP-induced activation of the mTORC2/AktSer473 pathway for cell survival contributes to cell transformation. E-cadherin and its mRNA were markedly reduced upon expression of dynAP, giving rise to cells with higher motility, which may be responsible for the weak cell-cell adhesion in tumors. Thus, dynAP could be a new oncoprotein and a target for cancer therapy.

Complementary DNA display selection of high-affinity peptides binding the vacuolating toxin (VacA) of Helicobacter pylori

Artificial peptides designed for molecular recognition of a bacterial toxin have been developed. Vacuolating cytotoxin A protein (VacA) is a major virulence factor of Helicobacter pylori, a gram-negative microaerophilic bacterium inhabiting the upper gastrointestinal tract, particularly the stomach. This study attempted to identify specific peptide sequences with high affinity for VacA using systematic directed evolution in vitro, a cDNA display method. A surface plasmon resonance-based biosensor and fluorescence correlation spectroscopy to examine binding of peptides with VacA identified a peptide (GRVNQRL) with high affinity. Cyclization of the peptide by attaching cysteine residues to both termini improved its binding affinity to VacA, with a dissociation constant (Kd ) of 58 nm. This study describes a new strategy for the development of artificial functional peptides, which are promising materials in biochemical analyses and medical applications.

Identification of Jumonji AT-Rich Interactive Domain 1A Inhibitors and Their Effect on Cancer Cells

Jumonji AT-rich interactive domain 1A (JARID1A), one of the jumonji C domain-containing histone demethylase (JHDM) family members, plays key roles in cancer cell proliferation and development of drug tolerance. Therefore, selective JARID1A inhibitors are potential anticancer agents. In this study, we searched for cell-active JARID1A inhibitors by screening hydroxamate compounds in our in-house library and the structural optimization based on docking study of the hit-compound to a homology model of JARID1A. As a result, we identified compound 6j, which selectively inhibits JARID1A over three other JHDM family members. Compound 7j, a prodrug form of compound 6j, induced a selective increase in the level of trimethylation of histone H3 lysine 4, a substrate of JARID1A. Furthermore, compound 7j synergistically enhanced A549 human lung cancer cell growth inhibition induced by vorinostat, a histone deacetylase inhibitor. These findings support the idea that JARID1A inhibitors have potential as anticancer agents.

The histone demethylase JMJD1A induces cell migration and invasion by up-regulating the expression of the long noncoding RNA MALAT1

Patients with neuroblastoma due to N-Myc oncogene amplification have a high frequency of tumor metastasis. However, it is not clear how N-Myc induces cell migration, invasion and metastasis. The histone demethylase JMJD1A activates gene transcription by demethylating the lysine 9 residue of histone H3 (H3K9) at target gene promoters. The long noncoding RNA MALAT1 induces lung cancer cell migration and plays a pivotal role in lung cancer metastasis. Here we demonstrated that N-Myc up-regulated the expression of JMJD1A in N-Myc oncogene-amplified human neuroblastoma cells by directly binding to the JMJD1A gene promoter. Affymetrix microarray studies revealed that the gene second most significantly up-regulated by JMJD1A was MALAT1. Consistent with this finding, RT-PCR and chromatin immunoprecipitation assays showed that JMJD1A bound to the MALAT1 gene promoter and demethylated histone H3K9 at the MALAT1 gene promoter. Moreover, JMJD1A and MALAT1 induced, while the small molecule JMJD1A inhibitor DMOG suppressed, neuroblastoma cell migration and invasion. Taken together, our data identify a novel pathway through which N-Myc causes neuroblastoma cell migration and invasion, and provide important evidence for further development of more potent JMJD1A/MALAT1 inhibitors for the prevention of tumor metastasis.

Design, synthesis, and biological activity of N-alkylated analogue of NCL1, a selective inhibitor of lysine-specific demethylase 1

A hybridization of NCL1 and compound 5 led to the identification of a potent lysine-specific demethylase 1 inhibitor 5.

Stearoyl-CoA desaturase 1 activity is required for autophagosome formation

Autophagy is one of the major degradation pathways for cytoplasmic components. The autophagic isolation membrane is a unique membrane whose content of unsaturated fatty acids is very high. However, the molecular mechanisms underlying formation of this membrane, including the roles of unsaturated fatty acids, remain to be elucidated. From a chemical library consisting of structurally diverse compounds, we screened for novel inhibitors of starvation-induced autophagy by measuring LC3 puncta formation in mouse embryonic fibroblasts stably expressing GFP-LC3. One of the inhibitors we identified, 2,5-pyridinedicarboxamide, N2,N5-bis[5-[(dimethylamino)carbonyl]-4-methyl-2-thiazolyl], has a molecular structure similar to that of a known stearoyl-CoA desaturase (SCD) 1 inhibitor. To determine whether SCD1 inhibition influences autophagy, we examined the effects of the SCD1 inhibitor 28c. This compound strongly inhibited starvation-induced autophagy, as determined by LC3 puncta formation, immunoblot analyses of LC3, electron microscopic observations, and p62/SQSTM1 accumulation. Overexpression of SCD1 or supplementation with oleic acid, which is a catalytic product of SCD1 abolished the inhibition of autophagy by 28c. Furthermore, 28c suppressed starvation-induced autophagy without affecting mammalian target of rapamycin activity, and also inhibited rapamycin-induced autophagy. In addition to inhibiting formation of LC3 puncta, 28c also inhibited formation of ULK1, WIPI1, Atg16L, and p62/SQSTM1 puncta. These results suggest that SCD1 activity is required for the earliest step of autophagosome formation.

Regulation of tissue factor pathway inhibitor-2 (TFPI-2) expression by lysine-specific demethylase 1 and 2 (LSD1 and LSD2)

Tissue factor pathway inhibitor-2 (TFPI-2) is a major inhibitor of extracellular matrix degradation. Decreases in TFPI-2 contribute to malignant tumor cell production, and TFPI-2 is a presumed tumor suppressor. TFPI-2 gene transcription is regulated by two epigenetic mechanisms: DNA methylation of the promoter and K4 methylation of histone 3 (H3). Lysine-specific demethylase 1 (LSD1) and LSD2 demethylate H3K4me2/1. LSD1 has been implicated in TFPI-2 regulation through both epigenetic mechanisms, but the involvement of LSD2 remains unknown. We prepared a monoclonal anti-LSD2 antibody that clearly distinguishes LSD2 from LSD1. Knockdown of LSD1 or LSD2 by siRNAs increased TFPI-2 protein and mRNA. Simultaneous knockdown of both LSD1 and LSD2 showed additive effects. Bisulfite sequencing revealed that CpG sites in the TFPI-2 promoter region were unmethylated. These results indicate that LSD2 also contributes to TFPI-2 regulation through histone modification, and that further studies of the involvement of LSD2 in tumor malignancy are warranted.

Synthesis, LSD1 Inhibitory Activity, and LSD1 Binding Model of Optically Pure Lysine-PCPA Conjugates

Compounds that inhibit the catalytic function of lysine-specific demethylase 1 (LSD1) are interesting as therapeutic agents. Recently, we identified three lysine-phenylcyclopropylamine conjugates, NCD18, NCD25, and NCD41, which are potent LSD1 inactivators. However, in our previous study, because we tested those compounds as mixtures of (1S,2R)- and (1R,2S)-disubstituted cyclopropane rings, the relationship between the stereochemistry of the cyclopropane ring and their biological activity remained unknown. In this work, we synthesized optically active compounds of NCD18, NCD25, and NCD41 and evaluated their LSD1 inhibitory activities. In enzyme assays, the LSD1 inhibitory activities of (1R,2S)-NCD18 and (1R,2S)-NCD25 were approximately eleven and four times more potent than those of the corresponding (1S,2R)-isomers, respectively. On the other hand, (1S,2R)-NCD41 was four times more potent than (1R,2S)-NCD41. Binding simulation with LSD1 indicated that the aromatic rings of the compounds and the amino group of the cyclopropylamine were important for the interaction with LSD1, and that the stereochemistry of the 1,2-disubstituted cyclopropane ring affected the position of the aromatic rings and the hydrogen bond formation of the amino group in the LSD1 catalytic site. These findings are expected to contribute to the further development of LSD1 inactivators.

Abstract P2-09-11: Identification of a novel inhibitor of triple-negative breast cancer cell growth by screening of a small molecule library

Background: Triple-negative breast cancers (TNBC) are defined as not having amplification of the estrogen receptor, progesterone receptor, or epidermal growth factor receptor 2. At present, recovery in patients is severely limited following diagnosis of metastatic TNBC, with less than 30% of patients surviving more than 5 years.. The most effective therapy to date is chemotherapy, which has been unsuccessful due to the lack of therapeutic targets for these aggressive cancers. To identify new molecular targets for TNBC, we have developed a novel method for drug discovery using active compounds for identification of pharmacodynamic biomarkers.

Methods: We used chemical informatics to design a small molecule library that has structural diversity. This library was used to screen for compounds that selectively inhibit the proliferation in TNBC cell lines. The differences in gene expression profiles in cell lines before and after the addition of selected compounds were analyzed and compared with control cells.

Results: We identified (E)-3-(3,4-dihydroxybenzylidene)-benzofuran-2(3H)-one (DBBF) that exhibited specific inhibition of the proliferation in a TNBC cell line, MDA-MB-468 with IC50 of 2.4 μM. Microarray analysis identified several signaling pathways, including the irinotecan pathway, which changed specifically in the TNBC cell lines by the addition of DBBF.

Conclusion: We have developed a novel research strategy that involves screening of selective inhibitors of TNBC cell line proliferation that can be used for identification of pharmacodynamic biomarkers for TNBC. The discovery of new pathways by this technique should lead to the identification of new therapeutic targets for this aggressive cancer.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-09-11.