2 research outputs found
A Proteometric Analysis of Human Kinome: Insight into Discriminant Conformation-dependent Residues
Because
of the success of imatinib, the first type-II kinase inhibitor
approved by the FDA in 2001, sustained efforts have been made by the
pharmaceutical industry to discover novel compounds stabilizing the
inactive conformation of protein kinases. On the seven type-II inhibitors
having reached the market, four were released in 2012, suggesting
an acceleration of the research of such a class of compounds. Still,
they represent less than a third of the protein kinase inhibitors
available to patients today. The identification of key residues involved
in the binding of this type of ligands in the kinase active site might
ease the design of potent and selective type-II inhibitors. In order
to identify those discriminant residues, we have developed a proteometric
approach combining residue descriptors of protein kinase sequences
and biological activities of various type-II kinase inhibitors. We
applied Partial Least Squares (PLS) regression to identify 29 key
residues that influence the binding of four type-II inhibitors to
most proteins of the kinome. The gatekeeper residue was found to be
the most relevant, confirming an essential role in ligand binding
as well as in protein kinase conformational changes. Using the newly
developed proteometric model, we predicted the propensity of each
protein kinase to be inhibited by type-II ligands. The model was further
validated using an external data set of protein/ligand activity pairs.
Other residues present in the kinase domain, and more specifically
in the binding site, have been highlighted by this approach, but their
role in biological mechanisms is still unknown
Peptide-Conjugated MRI Probe Targeted to Netrin-1, a Novel Metastatic Breast Cancer Biomarker
Despite
significant progress in cancer imaging and treatment
over
the years, early diagnosis and metastasis detection remain a challenge.
Molecular magnetic resonance imaging (MRI), with its high resolution,
can be well adapted to fulfill this need, requiring the design of
contrast agents which target specific tumor biomarkers. Netrin-1 is
an extracellular protein overexpressed in metastatic breast cancer
and implicated in tumor progression and the appearance of metastasis.
This study focuses on the design and preclinical evaluation of a novel
Netrin-1-specific peptide-based MRI probe, GdDOTA-KKTHDAVR (GdāK),
to visualize metastatic breast cancer. The targeting peptide sequence
was identified based on the X-ray structure of the complex between
Netrin-1 and its transmembrane receptor DCC. Molecular docking simulations
support the probe design. In vitro studies evidenced
submicromolar affinity of GdāK for Netrin-1 (KD = 0.29 Ī¼M) and good MRI efficacy (proton relaxivity, r1 = 4.75 mMā1 sā1 at 9.4 T, 37 Ā°C). In vivo MRI studies in a
murine model of triple-negative metastatic breast cancer revealed
successful tumor visualization at earlier stages of tumor development
(smaller tumor volume). Excellent signal enhancement, 120% at 2 min
and 70% up to 35 min post injection, was achieved (0.2 mmol/kg injected
dose), representing a reasonable imaging time window and a superior
contrast enhancement in the tumor as compared to Dotarem injection