Angiogenesis plays a crucial role in tumour progression and metastatic spread; therefore, the development of specific vectors targeting angiogenesis has attracted the attention of several researchers. Since angiogenesis-associated aminopeptidase N (APN/CD13) is highly expressed on the surface of activated endothelial cells of new blood vessels and a wide range of tumour cells, it holds great promise for imaging and therapy in the field of cancer medicine. The selective binding capability of asparagine-glycine-arginine (NGR) motif containing molecules to APN/CD13 makes radiolabelled NGR peptides promising radiopharmaceuticals for the non-invasive, real-time imaging of APN/CD13 overexpressing malignancies at the molecular level. Preclinical small animal model systems are major keystones for the evaluation of the in vivo imaging behaviour of radiolabelled NGR derivatives. Based on existing literature data, several positron emission tomography (PET) and single-photon emission computed tomography (SPECT) radioisotopes have been applied so far for the labelling of tumour vasculature homing NGR sequences such as Gallium-68 (⁶⁸Ga), Copper-64 (⁶⁴Cu), Technetium-99m (^99mTc), Lutetium-177 (¹⁷⁷Lu), Rhenium-188 (¹⁸⁸Re), or Bismuth-213 (²¹³Bi). Herein, a comprehensive overview is provided of the recent preclinical experiences with radiolabelled imaging probes targeting angiogenesis.

Spontaneous deamidation prompted backbone isomerization of Asn/Asp residues resulting in – most cases – the insertion of an extra methylene group into the backbone poses a threat to the structural integrity of proteins. Here we present a systematical analysis of how temperature, pH, presence of charged residues, but most importantly backbone conformation and dynamics affect isomerization rates as determined by nuclear magnetic resonance in the case of designed peptide-models. We demonstrate that restricted mobility (such as being part of a secondary structural element) may safeguard against isomerization, but this protective factor is most effective in the case of off-pathway folds which can slow the reaction by several magnitudes compared to their on-pathway counterparts. We show that the geometric descriptors of the initial nucleophilic attack of the isomerization can be used to classify local conformation and contribute to the design of stable protein drugs, antibodies or the assessment of the severity of mutations.

Development of novel cyclic NGR peptide–daunomycin conjugates with dual targeting property Development of novel cyclic NGR peptide–daunomycin conjugates with dual targeting property

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), α_vβ₃ integrin, matrix metalloproteinases (MMPs), or aminopeptidase N. The aim of this study is to involve new, easily accessible peptide sequences into the of neo-angiogenesis in malignant processes. Labelling of these peptide ligands with ⁶⁸Ga enable PET imaging of neo-vascularization.

H2A.Z-nucleosomes are present in both euchromatin and heterochromatin and it has proven difficult to interpret their disparate roles in the context of their stability features. Using an in situ assay of nucleosome stability and DT40 cells expressing engineered forms of the histone variant we show that native H2A.Z, but not C-terminally truncated H2A.Z (H2A.Z∆C), is released from nucleosomes of peripheral heterochromatin at unusually high salt concentrations. H2A.Z and H3K9me3 landscapes are reorganized in H2A.Z∆C-nuclei and overall sensitivity of chromatin to nucleases is increased. These tail-dependent differences are recapitulated upon treatment of HeLa nuclei with the H2A.Z-tail-peptide (C9), with MNase sensitivity being increased genome-wide. Fluorescence correlation spectroscopy revealed C9 binding to reconstituted nucleosomes. When introduced into live cells, C9 elicited chromatin reorganization, overall nucleosome destabilization and changes in gene expression. Thus, H2A.Z-nucleosomes influence global chromatin architecture in a tail-dependent manner, what can be modulated by introducing the tail-peptide into live cells.

Traditional drug screening methods use monolayer (2D) tumor cell cultures, which lack basic features of tumor complexity. As an alternative, 3D hydrogels have begun to emerge as simple, time‐, and cost‐saving systems. One of the most promising candidates, synthetic alkoxysilane‐PEG (polyethylene glycol)‐based hydrogels, are formed by “sol–gel” polymerization in an aqueous medium, which allows control over the incorporated elements. Our aims were to optimize siloxane‐PEG hydrogels for three different cell lines of skin origin and utilize these 3D hydrogels as a feasible drug (e.g., daunorubicin) screening assay. A drastic increase in survival and the formation of cellular aggregates (spheroids) could be observed in A2058 melanoma cells, but not in keratinocyte and endothelial cell lines. A deep‐learning neural network was trained to recognize and distinguish between the cellular formations and allowed the fast processing of hundreds of microscopic images. We developed an artificial intelligence (AI)‐assisted application (https://github.com/enyecz/CancerDetector2), which indicated that, in terms of average area of the spheroids treated with daunorubicin, A2058 melanoma cell 3D aggregates have better survival in a hydrogel containing 15% bis‐mono‐ethoxysilane‐PEG.