Mn-labelled Beta-cyclodextrin for Melanoma Imaging: A Proof-of-concept Preclinical Study.

Background/aim: As prostaglandin E2 (PGE2) and its receptors (EP2) are over-expressed on tumor cells and microenvironment, radiolabeled cyclodextrins targeting such biomolecules are valuable vector candidates in molecular cancer diagnostics. Using experimental melanoma models, we evaluated the in vivo imaging behavior of novel Manganese-52-labeled (Mn) randomly methylated beta-cyclodextrin ([Mn]Mn-DOTAGA-RAMEB) and compared it with the following well-established tumor-specific probes: melanocortin-1 receptor (MC1-R)-affine [Ga]Ga-DOTA-NAPamide and PGE2 selective [Ga]Ga-DOTAGA-RAMEB cyclodextrin.

Materials And Methods: Post-injection of [Ga]Ga-DOTA-NAPamide, [Ga]Ga-DOTAGA-RAMEB, and [Mn]Mn-DOTAGA-RAMEB into MC1-R positive B16F10 melanoma-bearing mice, tumor radio-pharmaceutical uptake was quantified in vivo and ex vivo using preclinical positron emission tomography (PET) and high-performance gamma counter.

SARS-CoV-2 Nucleocapsid Protein Is Not Responsible for Over-Activation of Complement Lectin Pathway.

The nucleocapsid (N) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a viral structural protein that is abundant in the circulation of infected individuals. Previous published studies reported controversial data about the role of the N protein in the activation of the complement system. It was suggested that the N protein directly interacts with mannose-binding lectin-associated serine protease-2 (MASP-2) and stimulates lectin pathway overactivation/activity.

Dominant suppressor genes of p53-induced apoptosis in Drosophila melanogaster.

One of the major functions of programmed cell death (apoptosis) is the removal of cells that suffered oncogenic mutations, thereby preventing cancerous transformation. By making use of a Double-Headed-EP (DEP) transposon, a P element derivative made in our laboratory, we made an insertional mutagenesis screen in Drosophila melanogaster to identify genes that, when overexpressed, suppress the p53-activated apoptosis. The DEP element has Gal4-activatable, outward-directed UAS promoters at both ends, which can be deleted separately in vivo.

Acute Myelomonoblastic Leukemia (My1/De): A Preclinical Rat Model.

Background/aim: Since acute myeloid leukemias still represent the most aggressive type of adult acute leukemias, the profound understanding of disease pathology is of paramount importance for diagnostic and therapeutic purposes. Hence, this study aimed to explore the real-time disease fate with the establishment of an experimental myelomonoblastic leukemia (My1/De) rat model using preclinical positron emission tomography (PET) and whole-body autoradiography.

Materials And Methods: In vitro [F]F-FDG uptake studies were performed to compare the tracer accumulation in the newly cultured My1/De tumor cell line (blasts) with that in healthy control and My1/De bone marrow suspensions.

Concomitant [F]F-FAZA and [F]F-FDG Imaging of Gynecological Cancer Xenografts: Insight into Tumor Hypoxia.

Background/aim: Herein we assessed the feasibility of imaging protocols using both hypoxia-specific [F]F-FAZA and [F]F-FDG in bypassing the limitations derived from the non-specific findings of [F]F-FDG PET imaging of tumor-related hypoxia.

Materials And Methods: CoCl-generated hypoxia was induced in multidrug resistant (Pgp+) or sensitive (Pgp-) human ovarian (Pgp- A2780, Pgp+ A2780AD), and cervix carcinoma (Pgp- KB-3-1, Pgp+ KB-V-1) cell lines to establish corresponding tumor-bearing mouse models. Prior to [F]F-FDG/[F]F-FAZA-based MiniPET imaging, in vitro [F]F-FDG uptake measurements and western blotting were used to verify the presence of hypoxia.

Beta-Secretase 1 Recruits Amyloid-Beta Precursor Protein to ROCK2 Kinase, Resulting in Erroneous Phosphorylation and Beta-Amyloid Plaque Formation.

The amyloidogenic processing of APP depends on two events: its phosphorylation by ROCK2 (at Thr654) and the phosphorylation of the APP-cleaving enzyme BACE1 (at Ser498). However, the mechanisms and structural details of APP-ROCK2 and BACE1-ROCK2 binding are unknown. Using direct physical methods in combination with an in silico approach, we found that BACE1 binds into the substrate-binding groove of ROCK2 with a low affinity (K = 18 µM), while no binding of APP to ROCK2 alone could be detected.

Insights into recent preclinical studies on labelled cyclodextrin-based imaging probes: Towards a novel oncological era.

As malignancies remain one of the major health concerns worldwide, increasing focus has been centered around the application of cyclodextrins (CDs) in cancer imaging and therapy due to their outstanding inclusion forming capability. Albeit the physicochemical properties of CDs were intensively elucidated, the spread of their clinical application is limited by the relative paucity of knowledge about their pharmacokinetic profile, especially biodistribution. Studies applying fluorescently- CDs, or CD-based MRI contrast agents revealed much about pharmacokinetics and diagnostic applications; however, derivatives labelled with positron emitters seem superior molecular probes in the investigation of the route of CDs in biological niche.

Overview of Prostaglandin E2 (PGE2)-Targeting Radiolabelled Imaging Probes from Preclinical Perspective: Lessons Learned and Road Ahead.

As malignancies still represent one of the major health concerns worldwide, early tumor identification is among the priorities of today's science. Given the strong association between cyclooxygenase-2 (COX-2)/prostaglandin E2 (PGE2), PGE2 receptors (EPs), and carcinogenesis, target-specific molecules directed towards the components of the COX2/PGE2/EP axis seem to be promising imaging probes in the diagnostics of PGE2pos. neoplasms and in the design of anti-cancer drugs.

Therapeutic Performance Evaluation of Bi-Labelled Aminopeptidase N (APN/CD13)-Affine NGR-Motif ([Bi]Bi-DOTAGA-cKNGRE) in Experimental Tumour Model: A Treasured Tailor for Oncology.

Since NGR-tripeptides (asparagine-glycine-arginine) selectively target neoangiogenesis-associated Aminopeptidase N (APN/CD13) on cancer cells, we aimed to evaluate the in vivo tumour targeting capability of radiolabelled, NGR-containing, ANP/CD13-selective [Bi]Bi-DOTAGA-cKNGRE in CD13pos. HT1080 fibrosarcoma-bearing severe combined immunodeficient CB17 mice. 10 ± 1 days after cancer cell inoculation, positron emission tomography (PET) was performed applying [Ga]Ga-DOTAGA-cKNGRE for tumour verification.

In vivo assessment of tumor targeting potential of Ga-labelled randomly methylated beta-cyclodextrin (RAMEB) and 2-hydroxypropyl-β-cyclodextrin (HPβCD) using positron emission tomography.

Cyclodextrin derivates (CyDs) can form complexes with cyclooxygenase-2 induced tumor promoting prostaglandin E2 (PGE2). Based on our previous observations, Ga-labelled CyDs may represent promising radiopharmaceuticals in the positron emission tomography (PET) diagnostics of PGE2 positive tumors. We aimed at evaluating the tumor-targeting potential of Ga-NODAGA conjugated randomly methylated beta-cyclodextrin (Ga-NODAGA-RAMEB) and 2-hydroxypropyl-β-cyclodextrin (Ga-NODAGA-HPβCD) using in vivo PET imaging with experimental tumor models.

In Vivo Preclinical Assessment of β-Amyloid-Affine [C]C-PIB Accumulation in Aluminium-Induced Alzheimer's Disease-Resembling Hypercholesterinaemic Rat Model.

Aluminum (Al) excess and hypercholesterinaemia are established risks of Alzheimer's disease (AD). The aim of this study was to establish an AD-resembling hypercholesterinaemic animal model-with the involvement of 8 week and 48 week-old Fischer-344 rats-by Al administration for the safe and rapid verification of β-amyloid-targeted positron emission tomography (PET) radiopharmaceuticals. Measurement of lipid parameters and β-amyloid-affine [C]C-Pittsburgh Compound B ([C]C-PIB) PET examinations were performed.

Dual Inhibitors of AChE and BACE-1 for Reducing Aβ in Alzheimer's Disease: From In Silico to In Vivo.

Alzheimer's disease (AD) is a complex and widespread condition, still not fully understood and with no cure yet. Amyloid beta (Aβ) peptide is suspected to be a major cause of AD, and therefore, simultaneously blocking its formation and aggregation by inhibition of the enzymes BACE-1 (β-secretase) and AChE (acetylcholinesterase) by a single inhibitor may be an effective therapeutic approach, as compared to blocking one of these targets or by combining two drugs, one for each of these targets. We used our ISE algorithm to model each of the AChE peripheral site inhibitors and BACE-1 inhibitors, on the basis of published data, and constructed classification models for each.

In Vivo Assessments of Mesoblastic Nephroma (Ne/De) and Myelomonoblastic Leukaemia (My1/De) Tumour Development in Hypercholesterolemia Rat Models.

Given the rising prevalence of lipid metabolic disorders and malignant diseases, we aimed to establish an in vivo hypercholesterinaemic tumour-bearing rat model for the induction and assessment of these conditions. A normal standard CRLT/N, 2 (baseline),- or 4 (2 + 2, pretreated)-week-long butter and cholesterol rich (BCR) diet was applied to mesoblastic nephroma (Ne/De) and myelomonoblastic leukaemia (My1/De) tumour-bearing and healthy control Long—Evans and Fischer 344 rats. The beginning of chow administration started in parallel with tumour induction and the 2 weeks of pre-transplantation in the baseline and pretreated groups, respectively.

Semisynthetic teicoplanin derivatives with dual antimicrobial activity against SARS-CoV-2 and multiresistant bacteria.

Patients infected with SARS-CoV-2 risk co-infection with Gram-positive bacteria, which severely affects their prognosis. Antimicrobial drugs with dual antiviral and antibacterial activity would be very useful in this setting. Although glycopeptide antibiotics are well-known as strong antibacterial drugs, some of them are also active against RNA viruses like SARS-CoV-2.

PET Probes for Preclinical Imaging of GRPR-Positive Prostate Cancer: Comparative Preclinical Study of [Ga]Ga-NODAGA-AMBA and [Sc]Sc-NODAGA-AMBA.

Gastrin-releasing peptide receptors (GRPR) are overexpressed in prostate cancer (PCa). Since bombesin analogue aminobenzoic-acid (AMBA) binds to GRPR with high affinity, scandium-44 conjugated AMBA is a promising radiotracer in the PET diagnostics of GRPR positive tumors. Herein, the GRPR specificity of the newly synthetized [Sc]Sc-NODAGA-AMBA was investigated in vitro and in vivo applying PCa PC-3 xenograft.

In vivo investigation of Gallium-68 and Bismuth-205/206 labeled beta cyclodextrin for targeted alpha therapy of prostaglandin E2 receptor-expressing tumors in mice.

Prostaglandin E2 (PGE2) molecule and its receptors play an important role in the development of malignancies and metastases therefore PGE2 may play a crucial role in the diagnosis and a new therapeutic target in the field of radionuclide therapy of PGE2-positive tumors. PGE2 form complexes with RAMEB (randomly-methylated-beta-cyclodextrin) with high affinity therefore the aim of this present study was to synthesize a PGE2-specific DOTAGA-RAMEB, which can be labeled with diagnostic and therapeutic isotopes also and binds to PGE2-positive tumors. DOTAGA-RAMEB was labeled with Ga and Bi radionuclides and their radiochemical purity (RCP%), partition coefficient (logP values), and in vitro and in vivo stability were determined.

Imaging of Neo-angiogenesis of Transplanted Metastases in Subrenal Capsule Assay Induced Rat Model.

Background/aim: Changes in the expression of neo-angiogenic molecules in the primary tumor and its metastases may significantly affect the efficacy of therapies. The aim of this study was to evaluate the alterations in aminopeptidase N (APN/CD13) and αβ integrin receptor expression in serially transplanted mesoblastic nephroma tumor (Ne/De) metastases using Gallium (Ga)-labeled NOTA-cNGR and NODAGA-RGD radiotracers and preclinical positron emission tomography (PET) imaging.

Materials And Methods: Primary and metastatic mesoblastic nephroma (Ne/De) tumors were induced by subrenal capsule assay (SRCA) in Fischer-344 rats.

Synthesis and characterization of new fluorescent boro-β-carboline dyes.

The first representatives of the new fluorescent boro-β-carboline family were synthesized by the insertion of the difluoroboranyl group into the oxaza or diaza core. The resulting compounds showed good photophysical properties with fine Stokes-shifts in the range of 38-85 nm with blue and green emission. The energetics of the excitation states and molecular orbitals of two members were investigated by quantum chemical computations suggesting effects for the improved properties of diazaborinino-carbolines over oxazaborolo-carbolines.

Robust Recombinant Expression of Human Placental Ribonuclease Inhibitor in Insect Cells.

Ribonuclease inhibitors (RIs) are an indispensable biotechnological tool for the detection and manipulation of RNA. Nowadays, due to the outbreak of COVID-19, highly sensitive detection of RNA has become more important than ever. Although the recombinant expression of RNase inhibitors is possible in , the robust expression is complicated by maintaining the redox potential and solubility by various expression tags.

Natural Apocarotenoids and Their Synthetic Glycopeptide Conjugates Inhibit SARS-CoV-2 Replication.

The protracted global COVID-19 pandemic urges the development of new drugs against the causative agent SARS-CoV-2. The clinically used glycopeptide antibiotic, teicoplanin, emerged as a potential antiviral, and its efficacy was improved with lipophilic modifications. This prompted us to prepare new lipophilic apocarotenoid conjugates of teicoplanin, its pseudoaglycone and the related ristocetin aglycone.

Rapid Identification of Potential Drug Candidates from Multi-Million Compounds' Repositories. Combination of 2D Similarity Search with 3D Ligand/Structure Based Methods and In Vitro Screening.

Rapid in silico selection of target focused libraries from commercial repositories is an attractive and cost-effective approach in early drug discovery. If structures of active compounds are available, rapid 2D similarity search can be performed on multimillion compounds' databases. This approach can be combined with physico-chemical parameter and diversity filtering, bioisosteric replacements, and fragment-based approaches for performing a first round biological screening.

In vivo preclinical assessment of novel Ga-labelled peptides for imaging of tumor associated angiogenesis using positron emission tomography imaging.

Formation and growth of metastases require a new vascular network. Angiogenesis plays an essential role in the expansion and progression of most malignancies. A high number of molecular pathways regulate angiogenesis, including vascular endothelial growth factor (VEGF), αβ integrin, matrix metalloproteinases (MMPs), or aminopeptidase N.

Ligand-induced conformational rearrangements regulate the switch between membrane-proximal and distal functions of Rho kinase 2.

Rho-associated protein kinase 2 (ROCK2) is a membrane-anchored, long, flexible, multidomain, multifunctional protein. Its functions can be divided into two categories: membrane-proximal and membrane-distal. A recent study concluded that membrane-distal functions require the fully extended conformation, and this conclusion was supported by electron microscopy.

Imaging of Hypoxia and Neoangiogenesis in Experimental Syngeneic Hepatocellular Carcinoma Tumor Model Using Positron Emission Tomography.

Introduction: Hypoxia-induced integrin and aminopeptidase N (APN/CD13) receptor expression play an important role in tumor neoangiogenesis. APN/CD13-specific Ga-NOTA-c(NGR), integrin-specific Ga-NODAGA-[c(RGD)], and hypoxia-specific Ga-DOTA-nitroimidazole enable the detection of the neoangiogenic process and the hypoxic regions in the tumor mass using positron emission tomography (PET) imaging. The aim of this study was to evaluate whether Ga-NOTA-c(NGR) and Ga-DOTA-nitroimidazole allow the noninvasive detection of the temporal changes of APN/CD13 expression and hypoxia in experimental He/De tumors using positron emission tomography.

In vivo preclinical evaluation of the new Ga-labeled beta-cyclodextrin in prostaglandin E2 (PGE2) positive tumor model using positron emission tomography.

The cyclooxygenase-2 (COX-2)/prostaglandin E2 (PGE2) pathway plays an important role in tumor development and formation of metastases. It was earlier reported that cyclodextrin derivatives have a high affinity to form complexes with PGE2. Based on these results radiolabeled cyclodextrins - as new radiopharmaceuticals - may open a new pathway in the in vivo imaging and diagnosis of PGE2 positive tumors.