A biotin-guided near-infrared fluorescent probe for imaging hydrogen sulfide and differentiating cancer cells.

Imaging cancer specific biomarkers with near-infrared (NIR) fluorescent probes can help inaccurate diagnosis. Hydrogen sulfide (H2S) has been reported to be involved in many physiological and pathological processes and is considered as one of the key gasotransmitters during the development of cancer. To achieve specific H2S detection in cancer cells, we reported a biotin-guided NIR fluorescent sensor P1 targeting a cancer cell surface biomarker, based on the H2S-specific thiolysis of the NBD-amine-hemicyanine conjugate. The probe showed a fast turn-on signal at 754 nm upon H2S activation and good selectivity towards H2S over millimolar levels of other biothiols. We successfully employed P1 to image endogenous H2S and demonstrated its tumor-targeting ability in live cells. P1 could differentiate multiple cancer cells with various levels of H2S from normal cells, indicating its potential for cancer imaging.

Four-dimensional digital design to prediction of the real-time functional rehabilitation in the esthetic zone.

Recent developments in digital technology and materials have improved the accuracy and efficiency of tracking and recording mandibular motion, with various methods being described. The present article describes a digital workflow with complete and accurate 3-dimensional spatial trajectories of mandibular motion to direct the design of lingual restorations. The workflow allowed the lingual curvature of the restoration to conform with the distinctive trajectory of mandibular protrusion.

Selection of Aptamers with Large Hydrophobic 2'-Substituents.

Previously, we evolved a DNA polymerase, SFM4-3, for the recognition of substrates modified at their 2' positions with a fluoro, O-methyl, or azido substituent. Here we use SFM4-3 to synthesize 2'-azido-modified DNA; we then use the azido group to attach different, large hydrophobic groups via click chemistry. We show that SFM4-3 recognizes the modified templates under standard conditions, producing natural DNA and thereby allowing amplification. To demonstrate the utility of this remarkable property, we use SFM4-3 to select aptamers with large hydrophobic 2' substituents that bind human neutrophil elastase or the blood coagulation protein factor IXa. The results indicate that SFM4-3 should facilitate the discovery of aptamers that adopt novel and perhaps more protein-like folds with hydrophobic cores that in turn allow them to access novel activities.

Preparing gelatin-containing polycaprolactone / polylactic acid nanofibrous membranes for periodontal tissue regeneration using side-by-side electrospinning technology.

Electrospinning technology has recently attracted increased attention in the biomedical field, and preparing various cellulose nanofibril membranes for periodontal tissue regeneration has unique advantages. However, the characteristics of using a single material tend to make it challenging to satisfy the requirements for a periodontal barrier film, and the production of composite fibrous membranes frequently impacts the quality of the final fiber membrane due to the influence of miscibility between different materials. In this study, nanofibrous membranes composed of polylactic acid (PLA) and polycaprolactone (PCL) fibers were fabricated using side-by-side electrospinning. Different concentrations of gelatin were added to the fiber membranes to improve their hydrophilic properties. The morphological structure of the different films as well as their composition, wettability and mechanical characteristics were examined. The results show that PCL/PLA dual-fibrous composite membranes with an appropriate amount of gelatin ensures sufficient mechanical strength while obtaining improved hydrophilic properties. The viability of L929 fibroblasts was evaluated using CCK-8 assays, and cell adhesion on the scaffolds was confirmed by scanning electron microscopy and by immunofluorescence assays. The results demonstrated that none of the fibrous membranes were toxic to cells and the addition of gelatin improved cell adhesion to those membranes. Based on our findings, adding 30% gelatin to the membrane may be the most appropriate content for periodontal tissue regeneration, considering the scaffold's mechanical qualities, hydrophilic properties and biocompatibility. In addition, the PCL-gelatin/PLA-gelatin dual-fibrous membranes prepared using side-by-side electrospinning technology have potential applications for tissue engineering.

Translational PET Imaging of Nectin-4 Expression in Multiple Different Cancers with 68Ga-N188.

Nectin cell adhesion molecule 4 (nectin-4) is a transmembrane protein overexpressed on a variety of cancers and plays an important role in oncogenic and metastatic processes. The nectin-4-targeted antibody-drug conjugate enfortumab vedotin has been approved for treating locally advanced or metastatic urothelial cancer, but the efficacy in other types of cancer remains to be explored. The aim of this study was to evaluate the feasibility of nectin-4-targeted PET imaging with 68Ga-N188 as a noninvasive method to quantify membranous nectin-4 expression in multiple tumor types-an approach that may provide insight for patient stratification and treatment selection. Methods: Sixty-two patients with 16 types of cancer underwent head-to-head 68Ga-N188 and 18F-FDG PET/CT imaging for initial staging or detection of recurrence and metastases. Correlation between lesion SUVmax and nectin-4 expression determined by immunohistochemistry staining was analyzed in 36 of 62 patients. Results: The SUVmax of 68Ga-N188 had a positive correlation with membranous nectin-4 expression in the various tumor types tested (r = 0.458; P = 0.005), whereas no association was observed between the SUVmax and cytoplasmic nectin-4 expression. The detection rates for patient-based analysis of 68Ga-N188 and 18F-FDG PET/CT examinations were comparable (95.00% [57/60] vs. 93.33% [56/60]). In patients with pancreatic cancer, 68Ga-N188 exhibited a potential advantage for detecting residual or locally recurrent tumors; this advantage may assist in clinical decision-making. Conclusion: The correlation between nectin-4-targeted 68Ga-N188 PET imaging and membranous nectin-4 expression indicates the potential of 68Ga-N188 as an effective tool for selecting patients who may benefit from enfortumab vedotin treatment. The PET imaging results provided evidence to explore nectin-4-targeted therapy in a variety of tumors. 68Ga-N188 may improve the restaging of pancreatic cancer but requires further evaluation in a powered, prospective setting.

First-in-Human Study of the Radioligand 68Ga-N188 Targeting Nectin-4 for PET/CT Imaging of Advanced Urothelial Carcinoma.

PURPOSE: Nectin-4 is an emerging biomarker for cancer diagnosis and therapy. Recently, enfortumab vedotin (EV) was approved by the FDA as the first nectin-4 targeting antibody-drug conjugate for treating advanced urothelial carcinoma (UC). A PET imaging method to noninvasively quantify nectin-4 expression level would potentially help to select patients most likely to respond to EV and predict the response. EXPERIMENTAL DESIGN: In this study, we designed a bicyclic peptide-based nectin-4 targeting radiotracer 68Ga-N188. Initially, we performed preclinical evaluations of 68Ga-N188 in UC cell lines and xenograft mouse models. Next, we performed the translational study in healthy volunteers and a pilot cohort of patients with advanced UC on uEXPLORER total-body PET/CT. RESULTS: In the preclinical study, 68Ga-N188 showed high affinity to nectin-4, specific uptake in a nectin-4(+) xenograft mouse model, and suitable pharmacokinetic and safety profiles. In the translational study, 2 healthy volunteers and 14 patients with advanced UC were enrolled. The pharmacokinetic profile was determined for 68Ga-N188, and the nectin-4 relative expression level in different organs was quantitatively imaged. CONCLUSIONS: A clear correlation between PET SUV value and nectin-4 expression was observed, supporting the application of 68Ga-N188 PET as a companion diagnostic tool for optimizing treatments that target nectin-4. See related commentary by Jiang et al., p. 3259.

Molecular PET/CT Profiling of ACE2 Expression In Vivo: Implications for Infection and Outcome from SARS-CoV-2.

Rapid progress has been made to identify and study the causative agent leading to coronavirus disease 2019 (COVID-19) but many questions including who is most susceptible and what determines severity remain unanswered. Angiotensin-converting enzyme 2 (ACE2) is a key factor in the infection process of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). In this study, molecularly specific positron emission tomography imaging agents for targeting ACE2 are first developed, and these novel agents are evaluated in vitro, in preclinical model systems, and in a first-in-human translational ACE2 imaging of healthy volunteers and a SARS-CoV-2 recovered patient (NCT04422457). ACE2 expression levels in different organs in live subjects are quantitatively delineated and observable differences are measured in the patient recovered from COVID-19. Surprising sites of uptake in the breast, reproductive system and very low uptake in pulmonary tissues are reported. This novel method can add a unique tool to facilitate SARS-CoV-2 related research and improve understanding of this enigmatic disease. Molecular imaging provides quantitative annotation of ACE2, the SARS-CoV-2 entry receptor, to noninvasively monitor organs impacted by the COVID-19.