Excess Peptide Research Articles

Applicable Machine Learning Model for Predicting Contrast-induced Nephropathy Based on Pre-catheterization Variables.

Objective Contrast agents used for radiological examinations are an important cause of acute kidney injury (AKI). We developed and validated a machine learning and clinical scoring prediction model to stratify the risk of contrast-induced nephropathy, considering the limitations of current classical and machine learning models. Methods This retrospective study included 38,481 percutaneous coronary intervention cases from 23,703 patients in a tertiary hospital. We divided the cases into development and internal test sets (8:2). Using the development set, we trained a gradient boosting machine prediction model (complex model). We then developed a simple model using seven variables based on variable importance. We validated the performance of the models using an internal test set and tested them externally in two other hospitals. Results The complex model had the best area under the receiver operating characteristic (AUROC) curve at 0.885 [95% confidence interval (CI) 0.876-0.894] in the internal test set and 0.837 (95% CI 0.819-0.854) and 0.850 (95% CI 0.781-0.918) in two different external validation sets. The simple model showed an AUROC of 0.795 (95% CI 0.781-0.808) in the internal test set and 0.766 (95% CI 0.744-0.789) and 0.782 (95% CI 0.687-0.877) in the two different external validation sets. This was higher than the value in the well-known scoring system (Mehran criteria, AUROC=0.67). The seven precatheterization variables selected for the simple model were age, known chronic kidney disease, hematocrit, troponin I, blood urea nitrogen, base excess, and N-terminal pro-brain natriuretic peptide. The simple model is available at http://52.78.230.235:8081/Conclusions We developed an AKI prediction machine learning model with reliable performance. This can aid in bedside clinical decision making.

Circulating Dipeptidyl Peptidase 3 Modulates Systemic and Renal Hemodynamics Through Cleavage of Angiotensin Peptides.

High circulating DPP3 (dipeptidyl peptidase 3) has been associated with poor prognosis in critically ill patients with circulatory failure. In such situation, DPP3 could play a pathological role, putatively via an excessive angiotensin peptides cleavage. Our objective was to investigate the hemodynamics changes induced by DPP3 in mice and the relation between the observed effects and renin-angiotensin system modulation. Ten-week-old male C57Bl/6J mice were subjected to intravenous injection of purified human DPP3 or an anti-DPP3 antibody (procizumab). Invasive blood pressure and renal blood flow were monitored throughout the experiments. Circulating angiotensin peptides and catecholamines were measured and receptor blocking experiment performed to investigate the underlying mechanisms. DPP3 administration significantly increased renal blood flow, while blood pressure was minimally affected. Conversely, procizumab led to significantly decreased renal blood flow. Angiotensin peptides measurement and an AT1R (angiotensin II receptor type 1) blockade experiment using valsartan demonstrated that the renovascular effect induced by DPP3 is due to reduced AT1R activation via decreased concentrations of circulating angiotensin II, III, and IV. Measurements of circulating catecholamines and an adrenergic receptor blockade by labetalol demonstrated a concomitant catecholamines release that explains blood pressure maintenance upon DPP3 administration. High circulating DPP3 increases renal blood flow due to reduced AT1R activation via decreased concentrations of circulating angiotensin peptides while blood pressure is maintained by concomitant endogenous catecholamines release.

The role of interleukin-22 in mammalian intestinal homeostasis: Friend and foe.

Interleukin-22 (IL-22) is an important cytokine in the intestinal environment. IL-22 is mainly produced by immune cells and targeted at nonimmune cells such as epithelial and stromal cells in a broad array of tissues such as -but not restricted to- the liver and adipose tissue. IL-22 therefore connects immune functions with metabolic functions of the host, and since it is induced by the microbiota, connects host functioning to the outside environment. IL-22 induces epithelial cell proliferation aiding in rapid epithelium regeneration and wound healing. Additionally, IL-22 activates antiapoptotic genes and DNA damage response pathways, enhancing epithelial cell survival. Recently, it has also been shown that IL-22 induces Paneth cell differentiation in humans. However, IL-22 can also contribute to intestinal epithelium damage and reduces microbial diversity in the intestine directly or indirectly by inducing excessive antimicrobial peptide production by epithelial cells. Moreover, IL-22 enhances angiogenesis and may therefore support tumorigenesis in the intestine. In conclusion, it appears that whether IL-22 has a beneficial or harmful effect in the mammalian intestine largely depends on its regulation. This review aims to provide a comprehensive overview of the current literature and emphasizes that IL-22 signaling outcome depends on the timing and duration of IL-22 production, the presence of it regulators such as IL-22BP, and the specific location of the cytokine production in the gastrointestinal tract.

Neurodevelopmental disorders and microcephaly: how apoptosis, the cell cycle, tau and amyloid-β precursor protein APPly.

Recent studies promote new interest in the intersectionality between autism spectrum disorder (ASD) and Alzheimer's Disease. We have reported high levels of Amyloid-β Precursor Protein (APP) and secreted APP-alpha (sAPP) and low levels of amyloid-beta (Aβ) peptides 1-40 and 1-42 (Aβ40, Aβ42) in plasma and brain tissue from children with ASD. A higher incidence of microcephaly (head circumference less than the 3rd percentile) associates with ASD compared to head size in individuals with typical development. The role of Aβ peptides as contributors to acquired microcephaly in ASD is proposed. Aβ may lead to microcephaly via disruption of neurogenesis, elongation of the G1/S cell cycle, and arrested cell cycle promoting apoptosis. As the APP gene exists on Chromosome 21, excess Aβ peptides occur in Trisomy 21-T21 (Down's Syndrome). Microcephaly and some forms of ASD associate with T21, and therefore potential mechanisms underlying these associations will be examined in this review. Aβ peptides' role in other neurodevelopmental disorders that feature ASD and acquired microcephaly are reviewed, including dup 15q11.2-q13, Angelman and Rett syndrome.

Whole genome sequencing identifies genetic variants associated with neurogenic inflammation in rosacea

Rosacea is a chronic inflammatory skin disorder with high incidence rate. Although genetic predisposition to rosacea is suggested by existing evidence, the genetic basis remains largely unknown. Here we present the integrated results of whole genome sequencing (WGS) in 3 large rosacea families and whole exome sequencing (WES) in 49 additional validation families. We identify single rare deleterious variants of LRRC4, SH3PXD2A and SLC26A8 in large families, respectively. The relevance of SH3PXD2A, SLC26A8 and LRR family genes in rosacea predisposition is underscored by presence of additional variants in independent families. Gene ontology analysis suggests that these genes encode proteins taking part in neural synaptic processes and cell adhesion. In vitro functional analysis shows that mutations in LRRC4, SH3PXD2A and SLC26A8 induce the production of vasoactive neuropeptides in human neural cells. In a mouse model recapitulating a recurrent Lrrc4 mutation from human patients, we find rosacea-like skin inflammation, underpinned by excessive vasoactive intestinal peptide (VIP) release by peripheral neurons. These findings strongly support familial inheritance and neurogenic inflammation in rosacea development and provide mechanistic insight into the etiopathogenesis of the condition.

18F-labeled FGFR1 peptide: a new PET probe for subtype FGFR1 receptor imaging.

The fibroblast growth factor receptor (FGFR) family is highly expressed in a variety of tumor types and represents a new target for cancer therapy. Different FGFR subtype aberrations have been found to exhibit highly variable sensitivity and efficacy to FGFR inhibitors. The present study is the first to suggest an imaging method for assessing FGFR1 expression. The FGFR1-targeting peptide NOTA-PEG2-KAEWKSLGEEAWHSK was synthesized by manual solid-phase peptide synthesis and high-pressure liquid chromatography (HPLC) purification and then labeled with fluorine-18 using NOTA as a chelator. In vitro and in vivo experiments were conducted to evaluate the stability, affinity and specificity of the probe. Tumor targeting efficacy and biodistribution were evaluated by micro-PET/CT imaging in RT-112, A549, SNU-16 and Calu-3 xenografts. The radiochemical purity of [18F]F-FGFR1 was 98.66% ± 0.30% (n = 3) with excellent stability. The cellular uptake rate of [18F]F-FGFR1 in the RT-112 cell line (FGFR1 overexpression) was higher than that in the other cell lines and could be blocked by the presence of excess unlabeled FGFR1 peptide. Micro-PET/CT imaging revealed a significant concentration of [18F]F-FGFR1 in RT-112 xenografts with no or very low uptake in nontargeted organs and tissues, which demonstrated that [18F]F-FGFR1 was selectively taken up by FGFR1-positive tumors. [18F]F-FGFR1 showed high stability, affinity, specificity and good imaging capacity for FGFR1-overexpressing tumors in vivo, which provides new application potential in the visualization of FGFR1 expression in solid tumors.

Initial preclinical evaluation of 68 Ga-DOTA-(Ser) 3 -LTVSPWY peptide as a PET radiotracer for glioblastoma targeting and imaging.

Imaging of glioblastoma multiform (GBM) tumor using 68 -Galium-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraaceticacid-Ser-Ser-Ser-Leu-Thr-Val-Ser-Pro-Trp-Tyr ( 68 Ga-DOTA-(Ser)3-LTVSPWY) as a PET radiotracer for HER2 receptor due to fact that this receptor plays a pivotal role in the tumorigenesis and tumor progression in a wide range of cancer. 68 Ga-DOTA-(Ser) 3 -LTVSPWY was produced with high radiochemical purity. The affinity and specificity of this radiotracer toward HER2 receptor on the surface of glioma glioblastoma (U-87 MG) cell line were evaluated. Furthermore, the biodistribution and PET imaging of this radiolabeled peptide were investigated on xenografted U-87 MG tumor-bearing mice. The in-vitro specific binding study revealed that the 68 Ga-DOTA-(Ser) 3 -LTVSPWY binds to different cell lines with respect to their level of HER2 expression. The calculated K D and B max of radiolabeled peptide toward U-87 MG cell line were 5.5 ± 2.4 nmol/l and (2.4 ± 0.3) × 10 5 receptors per cell, respectively. The highest tumor uptake was observed at 30-min postinjection, whereas the tumor-to-muscle ratio was about four-fold. The acquired PET images distinctively show tumor site, which was blocked with excess nonlabeled peptide that revealed specific in-vivo targeting of 68 Ga-DOTA-(Ser) 3 -LTVSPWY for glioma. 68 Ga-DOTA-(Ser) 3 -LTVSPWY specifically recognizes HER2 receptors and could be a potential candidate for GBM imaging.

Primary and secondary functions of HLA-E are determined by stability and conformation of the peptide-bound complexes.

SummaryMHC-E regulates NK cells by displaying MHC class Ia signal peptides (VL9) to NKG2A:CD94 receptors. MHC-E can also present sequence-diverse, lower-affinity, pathogen-derived peptides to T cell receptors (TCRs) on CD8+ T cells. To understand these affinity differences, human MHC-E (HLA-E)-VL9 versus pathogen-derived peptide structures are compared. Small-angle X-ray scatter (SAXS) measures biophysical parameters in solution, allowing comparison with crystal structures. For HLA-E-VL9, there is concordance between SAXS and crystal parameters. In contrast, HLA-E-bound pathogen-derived peptides produce larger SAXS dimensions that reduce to their crystallographic dimensions only when excess peptide is supplied. Further crystallographic analysis demonstrates three amino acids, exclusive to MHC-E, that not only position VL9 close to the α2 helix, but also allow non-VL9 peptide binding with re-configuration of a key TCR-interacting α2 region. Thus, non-VL9-bound peptides introduce an alternative peptide-binding motif and surface recognition landscape, providing a likely basis for VL9- and non-VL9-HLA-E immune discrimination.

Lipoprotein-Inspired Nanoscavenger for the Three-Pronged Modulation of Microglia-Derived Neuroinflammation in Alzheimer’s Disease Therapy

The inflammatory dysfunction of microglia from excess amyloid-β peptide (Aβ) disposal is an overlooked but pathogenic event in Alzheimer's disease (AD). Here, we exploit a native high-density lipoprotein (HDL)-inspired nanoscavenger (pHDL/Cur-siBACE1) that combines the trinity of phosphatidic acid-functionalized HDL (pHDL), curcumin (Cur), and β-site APP cleavage enzyme 1 targeted siRNA (siBACE1) to modulate microglial dysfunction. By mimicking the natural lipoprotein transport route, pHDL can penetrate the blood-brain barrier and sequentially target Aβ plaque, where Aβ catabolism is accelerated without microglial dysfunction. The benefit results are from a three-pronged modulation strategy, including promoted Aβ clearance with an antibody-like Aβ binding affinity, normalized microglial dysfunction by blocking the NF-κB pathway, and reduced Aβ production by gene silence (44%). After treatment, the memory deficit and neuroinflammation of APPswe/PSEN 1dE9 mice are reversed. Collectively, this study highlights the double-edged sword role of microglia and provides a promising tactic for modulating microglial dysfunction in AD treatment.

Topology‐Induced Chiral Amplification and Inversion in Self‐Assembling Dipeptide Films

AbstractSelf‐assembly of peptides into highly ordered chiral nanostructures has great potential applications in optics, sensing, biomedicine, and templated synthesis. However, the detailed mechanism for the chiral amplification and spontaneous ordering during the self‐assembly of peptides remains largely unexplored. Here, it is shown that by topology control of the co‐assembly of a simple dipeptide and a chiral diamine within a confined film, the supramolecular structures can be controlled precisely from hierarchically organized helical bundles to microcrystals and then parallel aligned nanohelices. The peptide and diamines can co‐assemble into aligned microcrystals when the molar ratio (χ = Cdiamine/Cpeptide) of the two components is 0.5. However, by changing the χ value, excess peptides or diamines create topological defects during the self‐assembly process. This leads to chiral amplification and the formation of long‐range‐ordered nanohelical arrays with controlled phase behaviors. Moreover, the formation of right‐ or left‐handed nanohelices can be further inversed by the topological control, without the need to change the chirality of the peptides. These findings provide new insights into the chiral self‐assembly of amyloid‐related peptides and offer a facile strategy to fabricate highly ordered functional materials.

Structure-Indicated LC-MS/MS Bioanalysis of Therapeutic Antibodies.

Monoclonal antibodies bind to Protein A/G resin with 100nm-diameter pores, which orients the Fab toward the reaction solution. Then, they can be proteolyzed using trypsin immobilized on the surface of 200nm-diameter nanoparticles. The difference between the two particle diameters allows Fab-selectiveproteolysis by limiting trypsin access to the antibody substrate. The specific signature peptide of monoclonal antibody is collected, which comprises the complementarity-determining regions (CDRs). Excess trypsin protease and peptide fragments from common sequences in Fc that inhibit the analysis can then be separated and removed. The resulting peptide samples are separated through high performance liquid chromatography on a 20nm-diameter pore-size reversed-phase C18 column. These are then sequentially ionized with an electrospray interface and subjected to mass spectrometry (MS). In MS, peptide ions are trapped and fragment ions are generated by the collision-induced dissociation with argon gas. These are detected with multiple reaction monitoring measurements to perform a highly sensitive and accurate quantitative analysis.By focusing on various physicochemical features at each analytical scene, such as characteristic structure and orientation of antibody, control of trypsin reaction field, carry-over on HPLC column, ionization suppression effect from endogenous proteins, and detection of amino acid sequence specificity of antibody, we optimized the overall conditions from the sample processing up to MS detection and developed analytical validation and clinical application of many therapeutic antibodies using our Fab-selective proteolysis technology that is based on the structure-indicated approach.

Chimeric virus-like particles (VLPs) designed from shrimp nodavirus (MrNV) capsid protein specifically target EGFR-positive human colorectal cancer cells

Recombinant MrNV capsid protein has been shown to effectively deliver plasmid DNA and dsRNA into Sf9 insect cells and shrimp tissues. To extend its application to cancer cell-targeting drug delivery, we created three different types of chimeric MrNV virus-like particles (VLPs) (R-MrNV, I-MrNV, and E-MrNV) that have specificity toward the epidermal growth factor receptor (EGFR), a cancer cell biomarker, by incorporating the EGFR-specific GE11 peptide at 3 different locations within the host cell recognition site of the capsid. All three chimeric MrNV-VLPs preserved the ability to form a mulberry-like VLP structure and to encapsulate EGFP DNA plasmid with an efficiency comparable to that previously reported for normal MrNV (N-MrNV). Compared to N-MrNV, the chimeric R-MrNV and E-MrNV carrying the exposed GE-11 peptide showed a significantly enhanced binding and internalization abilities that were specific towards EGFR expression in colorectal cancer cells (SW480). Specific targeting of chimeric MrNV to EGFR was proven by both EGFR silencing with siRNA vector and a competition with excess GE-11 peptide as well as the use of EGFR-negative colorectal cells (SW620) and breast cancer cells (MCF7). We demonstrated here that both chimeric R-MrNV and E-MrNV could be used to encapsulate cargo such as exogenous DNA and deliver it specifically to EGFR-positive cells. Our study presents the potential use of surface-modified VLPs of shrimp virus origin as nanocontainers for targeted cancer drug delivery.

An Integrin-αvβ6/α5β1-Bitargeted Probe for the SPECT Imaging of Pancreatic Adenocarcinoma in Preclinical and Primary Clinical Studies.

Pancreatic adenocarcinoma (PA) is one of the deadliest human malignancies. However, early detection, prediction of surgical resectability, and prognosis of PA are challenging with current conventional imaging technologies in the clinic. Molecular imaging technologies combined with novel imaging probes could be useful for early detection and accurate staging of PA. Integrin αvβ6 and α5β1 are found to be overexpressed in PA. In this study, integrin αvβ6/α5β1-bitargeted probes 99mTc-HYNIC-isoDGR (99mTc-isoDGR) and 99mTc-HYNIC-PEG4-PisoDGR2 (99mTc-3PisoDGR2) were prepared and evaluated in the BxPC-3 human pancreatic tumor model. Both subcutaneous and in situ BxPC-3 tumors could be clearly visualized by 99mTc-isoDGR nanoScan SPECT/CT imaging with a high ratio of tumor to background. The blocking study with excess nonradioactive peptide showed a significantly reduced tumor uptake, which confirmed the specificity of 99mTc-isoDGR. Biodistribution results confirmed the imaging results. The dimer tracer 99mTc-3PisoDGR2 significantly enhanced tumor uptake compared with 99mTc-isoDGR, and the spontaneous PA lesion in the mouse model could be clearly visualized by 99mTc-3PisoDGR2. The primary clinical study also verified the ability of 99mTc-3PisoDGR2 for detection of PA. Therefore, SPECT/CT imaging using the integrin αvβ6/α5β1-bitargeted 99mTc-3PisoDGR2 provided a potential approach for the noninvasive detection of PA.

Electronic structure and reactivity of heme bound insulin

Insulin resistance as well as insulin deficiency are said to be principal to the development of type 2 diabetes mellitus (T2Dm). Heme has also been suggested to play an important role in the disease etiology since many of the heme deficiency symptoms constitute the common pathological features of T2Dm. Besides, iron overload, higher heme iron intake and transfusion requiring diseases are associated with a higher risk of T2Dm development. In this study the interaction between these two key components i.e. heme and insulin has been studied spectroscopically under different conditions which include the effect of excess peptide as well as increasing pH. The resultant heme-insulin complexes in their reduced state are found to produce very little partially reduced oxygen species (PROS) on getting oxidized by molecular oxygen. The interaction between insulin and previously reported T2Dm relevant heme-amylin complex were also examined using absorption and resonance Raman spectroscopy. The corresponding data suggest that insulin sequesters heme from heme-amylin to form the much less cytotoxic heme-insulin.

Abstract PO-009: Genetically engineered exosomes enable active pancreatic cancer targeting and evading mononuclear phagocytic system

Abstract Introduction: Exosomes are emerging as promising nanocarriers for genes and drugs; however, major challenges exist including the absence of active tumor targeting and a high proportion of clearance by mononuclear phagocytic system (MPS) in liver and spleen. To overcome these obstacles currently preventing the effective application of nanodelivery technology in the field of cancer biology, we generate a novel exosome that recognizes both pancreatic ductal adenocarcinoma (PDAC) specific cell surface marker avb3 and the signal regulatory protein (SIRPa) on macrophages. Using this novel exosome, we have achieved active PDAC targeting and MPS evasion. Methods: We engineered the CD9, an exosome marker, to display a HA tagged RGD peptide at the E174 site of CD9 (CD9-HA-RGD). We overexpressed CD9-HA-RGD and a Flag tagged CD47 (CD47-Flag) in HEK 293 cells. CD47, a “don’t eat me” protein signal, mediates inhibition of phagocytosis through interacting with SIRPa on macrophages. Exosomes overexpressing CD9-HA-RGD and CD47-Flag were harvested from HEK 293 cell culture media by ultracentrifugation followed by purification with size exclusion chromatography (SEC). Exosomes displaying RGD and CD47 (Exo-RGD/CD47) were characterized in vitro using ELISA, western blot (WB), flow cytometry (FCM), PDAC cell uptake, and macrophage phagocytosis assays. Exo-RGD/CD47 was also evaluated in vivo in patient-derived PDAC cell line (PDCL5) orthotopic xenograft mouse model. Results: RGD and CD47 were demonstrated to be successfully displayed on exosome surface by analysis of HA and Flag expression using ELISA and FCM. Engineered Exo-RGD/CD47 exosomes achieved enhanced cell binding and increased uptake capacities in an avb3 expression dependent manner in PDAC cells. This was confirmed using excess RDG peptide in a competition assay. Control exosomes demonstrated low uptake efficiency by PDAC cells. Exo-RGD/CD47 resulted in 71.5% reduction of macrophage phagocytosis when compared to control exosomes as evaluated by THP1 cells phagocytosis assay. Using DiR stained exosomes, we demonstrated that Exo-RGD/CD47 systemic delivery significantly reduced liver accumulation up to 80.6% and 65.8% after 1h and 6h after injection, respectively, as compared to control group (p<0.05). Similarly, Exo-RGD/CD47 delivery resulted in 70.1% reduction of splenic accumulation as compared to control at 6h after application (p<0.05). Exo-RGD/CD47 systemic delivery also showed significant tumor accumulation in the PDCL5 xenograft tumor model as compared to control (p<0.05). Conclusions: These data demonstrate that CD9 is an editable exosome biomarker by which peptides can be effectively displayed on the surface of an exosome. Displaying RGD and CD47 on the exosome surface results in a novel exosome that enables active PDAC targeting and evasion of phagocytosis by MPS. These findings suggest the newly designed exosome may have a better translational potential in PDAC diagnosis and therapy than traditional exosomes. Citation Format: Shi-He Liu, Justin Creeden, F. Charles Brunicardi, JianTing Zhang. Genetically engineered exosomes enable active pancreatic cancer targeting and evading mononuclear phagocytic system [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2020 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2020;80(22 Suppl):Abstract nr PO-009.

Synthesis of a novel 99mTc labeled GE11 peptide for EGFR SPECT imaging

Purpose This study investigated a novel SPECT agent for the noninvasive imaging of EGFR-overexpressing tumors. Methods The EGFR-targeting peptide GE11 was synthesized with the introduction of four amino acids (GGGC) to its C-terminal to act as a strong chelator and radiolabeled using 99mTc. The radiochemical yield of the 99mTc-peptide-GE11 were evaluated using RP-HPLC. Cellular assays of the probe were performed on two NSCLC cell lines: A549 (high expression) and H23 (low expression). Biodistribution and SPECT imaging were performed in BALB/c nude mice bearing A549 and H23 NSCLC xenografts. Results The 99mTc-peptide-GE11 was prepared at high efficiency with radiochemical yield of 98.40 ± 1.00 % and it showed favorable stability. The cellular uptake was significantly higher in A549 than in H23 at all time points (especially at 1 h, which was 10.34 ± 0.72 and 2.04 ± 0.18, respectively). A nearly 56% reduction in probe uptake was observed after pretreatment with excess unlabeled peptides. The performance of SPECT imaging and biodistribution demonstrated higher uptake of the 99mTc-peptide-GE11 in A549 xenograft than in H23 xenografts. Conclusion The new SPECT tracer 99mTc-peptide-GE11 showed EGFR specificity, favorable pharmacokinetics and great potential for EGFR-targeted imaging.

Positron emission tomography imaging of a novel Anxa1-targeted peptide 18 F-Al-NODA-Bn-p-SCN-GGGRDN-IF7 in A431 cancer mouse models.

Annexin 1 (Anxa1) is a highly specific surface marker of tumor vasculature in the lung and prostate solid tumors. The IF7 peptide was modified with a hydrophilic linker, GGGRDN, and coupled with a new bifunctional chelating agent NODA-Bn-p-SCN. The resulting peptides (NODA-Bn-p-SCN-GGGRDN-IF7) were successfully labeled with Al18 F. The targeting characteristics of the radiolabeled peptides were evaluated in the Anxa1 positive A431 tumor model. Micro-positron emission tomography (micro-PET) imaging revealed that the A431 tumors were clearly visualized (5.74 ± 1.13%ID/g, 3.92 ± 0.78%ID/g and 1.30 ± 0.43%ID/g at 0.5, 1, and 2 h post-injection, respectively). Anxa1 binding specificity was also demonstrated by reduced tumor uptake after co-injection with excessive unlabeled GGGRDN-IF7 peptide at 30, 60, and 120 min post-injection. 18 F-Al-NODA-Bn-p-SCN-GGGRDN-IF7 might be a potential PET imaging agent for detecting Anxa1 levels in cancers due to the favorable characteristics such as convenient synthesis, specific Anxa1 targeting, and good tumor uptakes.

Guidance and best practices for nuclear cardiology laboratories during the coronavirus disease 2019 (COVID-19) pandemic: An Information Statement from ASNC and SNMMI

1022 Purpose: The programmed death-ligand 1 (PD-L1) immunohistochemistry correlates moderately with the response to PD-L1 immunomodulatory therapy. Here we present the initial results from the studies to assess the feasibility of non-invasive PD-L1 imaging with 68Ga-WL12 (a 12-mer anti-PD-L1 peptide) radiotracer from animal experiments to the first-in-human study. Methods: PD-L1 binding peptide, NOTA-WL12, was synthesized by custom services with >95% chemical purity. , we generated 68Ga-WL12 with high specific radioactivity and radiochemical purity. We select human non-small cell lung cancer cells ( HCC827) , which with moderate expression of PD-L1. To demonstrate PD-L1-specific binding of 68Ga-WL12, both binding affinity test and cell uptakes were carried out with excess WL12. Normal Mice were used for PET/CT imaging and biodistribution study. Finally, we recruited a patient ( 80 years old female ;ethical approval No.2019KT) with non-small cell lung cancer who was positive for PD-L1(>80%) and performed PET/CT imaging with 68Ga-WL12 before and after immunomodulatory therapy. Results: To demonstrate PD-L1 specificity and cell uptake, we generated 68Ga-WL12 with radiochemical purity >99% after purification, specific activity 27.8-111.2 GBq/umol. High 68Ga-WL12 uptake was observed in PD-L1-positive HCC827 cells. TO confirming radiotracer specificity, we observed a significant reduction in bound 68Ga-WL12 in the presence of the excess unmodified peptide, indicating that 68Ga-WL12 binding to PD-L1 is specific. We performed PET imaging of the tumor model with 68Ga-WL12. The uptake value was consistent with tracer biodistribution. Finally, in this first-in-human assessment of 68Ga-WL12, we show that the imaging signal corresponds to PD-L1 expression at sites of the primary tumor and metastatic focus. The SUVpeak of different tumor lesions ranged from 2.0 to 6.0. The SUV value of PD-L1 positive tumors decreased significantly after immunomodulatory therapy. Conclusions: In this study, we demonstrated that 68Ga-WL12 exhibited a high affinity to PD-L1 in the Cell uptake experiment in vitro. 68Ga-WL12 demonstrated PD-L1 specific uptake first-in-human study. Therefore, 68Ga-WL12 PET/CT imaging may be a useful tool to assess PD-L1 expression in lesions. Future clinical studies are needed to confirm our findings in a larger patient population, to comprehensively assess different 68Ga-WL12 uptake features in combination with other clinical data to optimize therapy response prediction, and to evaluate whether 68Ga-WL12 PET could also be used as a response predictor for treatment with other monoclonal antibodies targeting the PD-1/PD-L1 axis.

Guidance and best practices for nuclear cardiology laboratories during the coronavirus disease 2019 (COVID-19) pandemic: An Information Statement from ASNC and SNMMI.

1022 Purpose: The programmed death-ligand 1 (PD-L1) immunohistochemistry correlates moderately with the response to PD-L1 immunomodulatory therapy. Here we present the initial results from the studies to assess the feasibility of non-invasive PD-L1 imaging with 68Ga-WL12 (a 12-mer anti-PD-L1 peptide) radiotracer from animal experiments to the first-in-human study. Methods: PD-L1 binding peptide, NOTA-WL12, was synthesized by custom services with >95% chemical purity. , we generated 68Ga-WL12 with high specific radioactivity and radiochemical purity. We select human non-small cell lung cancer cells ( HCC827) , which with moderate expression of PD-L1. To demonstrate PD-L1-specific binding of 68Ga-WL12, both binding affinity test and cell uptakes were carried out with excess WL12. Normal Mice were used for PET/CT imaging and biodistribution study. Finally, we recruited a patient ( 80 years old female ;ethical approval No.2019KT) with non-small cell lung cancer who was positive for PD-L1(>80%) and performed PET/CT imaging with 68Ga-WL12 before and after immunomodulatory therapy. Results: To demonstrate PD-L1 specificity and cell uptake, we generated 68Ga-WL12 with radiochemical purity >99% after purification, specific activity 27.8-111.2 GBq/umol. High 68Ga-WL12 uptake was observed in PD-L1-positive HCC827 cells. TO confirming radiotracer specificity, we observed a significant reduction in bound 68Ga-WL12 in the presence of the excess unmodified peptide, indicating that 68Ga-WL12 binding to PD-L1 is specific. We performed PET imaging of the tumor model with 68Ga-WL12. The uptake value was consistent with tracer biodistribution. Finally, in this first-in-human assessment of 68Ga-WL12, we show that the imaging signal corresponds to PD-L1 expression at sites of the primary tumor and metastatic focus. The SUVpeak of different tumor lesions ranged from 2.0 to 6.0. The SUV value of PD-L1 positive tumors decreased significantly after immunomodulatory therapy. Conclusions: In this study, we demonstrated that 68Ga-WL12 exhibited a high affinity to PD-L1 in the Cell uptake experiment in vitro. 68Ga-WL12 demonstrated PD-L1 specific uptake first-in-human study. Therefore, 68Ga-WL12 PET/CT imaging may be a useful tool to assess PD-L1 expression in lesions. Future clinical studies are needed to confirm our findings in a larger patient population, to comprehensively assess different 68Ga-WL12 uptake features in combination with other clinical data to optimize therapy response prediction, and to evaluate whether 68Ga-WL12 PET could also be used as a response predictor for treatment with other monoclonal antibodies targeting the PD-1/PD-L1 axis.

An Integrin Alpha 6-Targeted Radiotracer with Improved Receptor Binding Affinity and Tumor Uptake.

In this study, we reported a 99mTc-labeled integrin α6-targeted peptide as the molecular imaging probe for tumor imaging by single-photon emission computed tomography (SPECT). We found that replacing Cys-Cys cyclized RWY peptide (sequence: cCRWYDENAC) with lactam-bridged cyclic cKiE peptide (sequence: cKRWYDENAisoE) did not sacrifice the integrin α6-binding affinity and specificity of cKiE radiotracer. To further improve the radiotracer's tumor targeting capability, the dimerized cKiE peptide (termed cKiE2) was designed, and the corresponding radiotracer 99mTc-cKiE2 was evaluated for tumor uptake and in vivo pharmacokinetics properties in tumor models. We found that cKiE2 showed higher binding affinity to integrin α6 than did monomeric RWY or cKiE peptide. The biodistribution results showed that the tumor uptake of 99mTc-cKiE2 was twice higher than that of 99mTc-RWY (3.20 ± 0.12 vs 1.26 ± 0.06 %ID/g, P < 0.001) at 0.5 h postinjection. The tumor to nontargeting tissue ratios were also enhanced in most normal organs. Specificity of 99mTc-cKiE2 for integrin α6 was demonstrated by competitive blocking of tumor uptake with excess cold peptide (3.20 ± 0.24 to 1.38 ± 0.23 %ID/g, P < 0.001). The integrin α6-positive tumors were clearly visualized by 99mTc-cKiE2/SPECT with low background except with a relatively high kidney uptake. The tumor uptake of 99mTc-cKiE2 correlates well with the tumor integrin α6 expression levels in a linear fashion (R2 = 0.9623). We also compared 99mTc-cKiE2 with an integrin αvβ3-targeted radiotracer 99mTc-3PRGD2 in the orthotopic hepatocellular carcinoma tumor models. We found that the orthotopic tumor was clearly visualized with 99mTc-cKiE2. 99mTc-3PRGD2 imaging did not show tumor contours in situ as clearly as 99mTc-cKiE2. The tumor-to-liver ratios of 99mTc-cKiE2 and 99mTc-3PRGD2 were 2.20 ± 0.17 and 0.85 ± 0.20. In conclusion, 99mTc-cKiE2 is an improved SPECT radiotracer for imaging integrin α6-positive tumors and has great potential for further clinical application.