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J Am Chem Soc ; 143(48): 20095-20108, 2021 12 08.
Article in English | MEDLINE | ID: covidwho-1531986


Chemical modifications of native proteins can affect their stability, activity, interactions, localization, and more. However, there are few nongenetic methods for the installation of chemical modifications at a specific protein site in cells. Here we report a covalent ligand directed release (CoLDR) site-specific labeling strategy, which enables the installation of a variety of functional tags on a target protein while releasing the directing ligand. Using this approach, we were able to label various proteins such as BTK, K-RasG12C, and SARS-CoV-2 PLpro with different tags. For BTK we have shown selective labeling in cells of both alkyne and fluorophores tags. Protein labeling by traditional affinity methods often inhibits protein activity since the directing ligand permanently occupies the target binding pocket. We have shown that using CoLDR chemistry, modification of BTK by these probes in cells preserves its activity. We demonstrated several applications for this approach including determining the half-life of BTK in its native environment with minimal perturbation, as well as quantification of BTK degradation by a noncovalent proteolysis targeting chimera (PROTAC) by in-gel fluorescence. Using an environment-sensitive "turn-on" fluorescent probe, we were able to monitor ligand binding to the active site of BTK. Finally, we have demonstrated efficient CoLDR-based BTK PROTACs (DC50 < 100 nM), which installed a CRBN binder onto BTK. This approach joins very few available labeling strategies that maintain the target protein activity and thus makes an important addition to the toolbox of chemical biology.

Agammaglobulinaemia Tyrosine Kinase/chemistry , Fluorescent Dyes/chemistry , Ligands , Proto-Oncogene Proteins p21(ras)/antagonists & inhibitors , Adenine/analogs & derivatives , Adenine/chemistry , Adenine/metabolism , Agammaglobulinaemia Tyrosine Kinase/metabolism , Catalytic Domain , Coronavirus Papain-Like Proteases/chemistry , Coronavirus Papain-Like Proteases/metabolism , Half-Life , Humans , Piperidines/chemistry , Piperidines/metabolism , Proteolysis , Proto-Oncogene Proteins p21(ras)/genetics , Proto-Oncogene Proteins p21(ras)/metabolism , Pyrimidines/chemistry , Pyrimidines/metabolism , SARS-CoV-2/enzymology
Exp Mol Pathol ; 120: 104634, 2021 06.
Article in English | MEDLINE | ID: covidwho-1152690


Lung and colorectal cancers (CRC) have two of the highest mortality rates among all cancer types, and their occurrence and the need for personalized diagnostics and subsequent therapy were not influenced by the COVID-19 pandemics. However, due to the disruption of established delivery chains, standard assays for in vitro diagnostics of those cancers were temporarily not available, forcing us to implement alternative testing methods that enabled at least basic therapy decision making. For this reason, we evaluated rapid testing on the Biocartis Idylla™ platform (Biocartis, Mechelen, Belgium) for four important genes commonly mutated in lung and colorectal cancers, namely EGFR, NRAS, KRAS, and BRAF. Clinical specimens from which the mutation status has previously been determined using Next Generation Sequencing (NGS), were retested to determine whether Idylla™ can offer accurate results. To compare the results, the sensitivity, specificity, positive predictive values (PPV) and negative predictive values (NPV) are calculated for each of the mutation types and then combined to determine the values of the Idylla™ system in total, while setting NGS as the gold-standard basis the assays were compared with. Idylla testing thereby displayed acceptable sensitivity and specificity and delivered reliable results for initial therapy decisions.

DNA Mutational Analysis/methods , GTP Phosphohydrolases/genetics , High-Throughput Nucleotide Sequencing/methods , Membrane Proteins/genetics , Mutation , Proto-Oncogene Proteins B-raf/genetics , Proto-Oncogene Proteins p21(ras)/genetics , COVID-19/epidemiology , COVID-19/prevention & control , COVID-19/virology , Colorectal Neoplasms/diagnosis , Colorectal Neoplasms/genetics , ErbB Receptors/genetics , Humans , Lung Neoplasms/diagnosis , Lung Neoplasms/genetics , Pandemics , Reproducibility of Results , SARS-CoV-2/isolation & purification , SARS-CoV-2/physiology , Sensitivity and Specificity
Expert Rev Mol Diagn ; 21(1): 101-107, 2021 01.
Article in English | MEDLINE | ID: covidwho-962282


Background: The SARS-CoV-2 pandemic introduced a global distraction effect in cancer patients' care. The aim of this study was to explore the effect of the pandemic on the largest molecular diagnostics center for cancer patients and high-risk individuals in Serbia.Research design and methods: EGFR, KRAS/NRAS, BRAF, and BRCA1/2 mutation testing were performed by qPCR and NGS. NGS was used for panel testing of hereditary breast/ovarian cancer and cancers associated with Lynch syndrome. The analytical output during the state of emergency (SoE) was compared to the period before and after the outbreak using one-way ANOVA. Statistical significance was set at p < 0.05.Results: A 38% reduction in the number of analysis was detected during the SoE. After the SoE, a 19% reduction was noted compared to SoE and 50% compared to the period before the SoE (p = 0.038). Three of the 48 scheduled appointments for pretest genetic counseling were carried out during the SoE, but the number of NGS tests increased by 50%.Conclusions: The SARS-CoV-2 pandemic had a profound negative effect on the diagnostic output of our centralized molecular diagnostics center. The only positive effect was shortening of waiting lists for hereditary cancer patients and high-risk individuals.

Breast Neoplasms/diagnosis , Colorectal Neoplasms, Hereditary Nonpolyposis/diagnosis , Mutation , Ovarian Neoplasms/diagnosis , BRCA1 Protein/genetics , BRCA2 Protein/genetics , Breast Neoplasms/genetics , COVID-19 , Colorectal Neoplasms, Hereditary Nonpolyposis/genetics , DNA Mutational Analysis , ErbB Receptors/genetics , Female , GTP Phosphohydrolases/genetics , Genetic Counseling , Genetic Predisposition to Disease , Humans , Liquid Biopsy , Membrane Proteins/genetics , Ovarian Neoplasms/genetics , Pandemics , Pathology, Molecular , Pharmacogenetics , Proto-Oncogene Proteins B-raf/genetics , Proto-Oncogene Proteins p21(ras)/genetics , Serbia/epidemiology