Biology subjects

Asciutto, E. K.

Publications and source records attributed to Asciutto, E. K..

3 recordsLinked to original sources

bioRxiv2024

A CYCLIC PEPTIDE TARGETS GLIOBLASTOMA BY BINDING TO ABERRANTLY EXPOSED SNAP25

Disease-specific changes in tumors and other diseased tissues are an important target of research because they provide clues on the pathophysiology of the disease as well as uncovering potentially useful markers for diagnosis and treatment. Here, we report a new cyclic peptide, CESPLLSEC (CES), that specifically accumulated (homed) in intracranial U87MG and the WT-GBM model of glioblastoma from intravenous (IV) injection, associating with the vasculature. Affinity chromatography of U87MG tumor extracts on insolubilized CES peptide identified Synaptosomal Associated Protein 25 (SNAP25) as a candidate target molecule (receptor) for CES. Several results supported the identification of SNAP25 as the CES receptor. IV-injected FAM-CES colocalized with SNAP25 in the tumors, and direct binding studies showed specific CES peptide binding to recombinant human SNAP25. A CES peptide-drug conjugate designed for photodynamic therapy showed selective cytotoxicity to SNAP25+ glioblastoma cell lines. Specific accumulation of systemically injected anti-SNAP25 antibody in U87MG glioblastoma, and labeling of intact U87MG cells with anti-SNAP in flow cytometry showed that SNAP25 is available from the circulation but not in normal tissues and that it is present at the cell surface. Using an array of ECM proteins and surface plasmon resonance revealed that SNAP25 binds moderately to collagen V and strongly to collagen VI. Modeling studies suggested that CES and collagen VI compete for the same binding site on SNAP25. Our results introduce CES as a valuable targeting peptide for drug delivery, and its receptor SNAP25 as a possible molecular marker of interest for glioblastoma.

cancer biology↗

bioRxiv2024

Therapeutic Tumor Macrophage Reprogramming in Breast Cancer Through a Peptide-Drug Conjugate

In triple negative breast cancer (TNBC), pro-tumoral macrophages promote metastasis and suppress the immune response. To target these cells, we engineered a previously identified CD206 (mannose receptor)-binding peptide, mUNO, to enhance its affinity and proteolytic stability. The new rationally designed peptide, MACTIDE, includes a trypsin inhibitor loop, from the Sunflower Trypsin Inhibitor-I. Binding studies to recombinant CD206 revealed a 15-fold lower KD for MACTIDE compared to parental mUNO. Additionally, mass spectrometry showed a 5-fold increase in half-life in tumor lysate for MACTIDE compared to mUNO. Homing studies in TNBC-bearing mice showed that fluorescein (FAM)-MACTIDE precisely targeted CD206+ tumor-associated macrophages (TAMs) upon intravenous, intraperitoneal and even oral administration, with no significant accumulation in liver. We coupled MACTIDE to the FDA-approved drug Verteporfin, an established photosensitizer for photodynamic therapy and inhibitor of the YAP/TAZ pathway, to generate a conjugate here referred to as MACTIDE-V. In the orthotopic 4T1 TNBC mouse model, non-irradiated MACTIDE-V-treated mice unexpectedly showed a similar anti-tumoral effect and fewer signs of toxicity as irradiated MACTIDE-V-treated mice, leading to subsequent studies on the laser-independent activity of this conjugate. In vitro studies using bone-marrow derived mouse macrophages showed that MACTIDE-V excluded YAP from the nucleus, increased the phagocytic activity and upregulated several genes associated with cytotoxic anti-tumoral macrophages. In mouse models of TNBC, MACTIDE-V slowed primary tumor growth, suppressed lung metastases, increased markers of phagocytosis and antigen presentation in TAMs and monocytes, increasing the tumor infiltration of several lymphocyte subsets. We therefore propose MACTIDE-V as a useful peptide-drug conjugate to modulate macrophage function in the context of breast tumor immunotherapy.

cancer biology↗

bioRxiv2020

Physical Interactions Driving the Activation/Inhibition of Calcium/Calmodulin Dependent Protein Kinase II

CaMKII is a protein kinase whose function is regulated by the binding of the Calcium/Calmodulin complex (Ca2+/CaM). It is a major player in the Long Term Potentiation process where it acts as a molecular switch, oscillating between inhibited and active conformations. The mechanism for the switching is thought to be initiated by Ca2+/CaM binding, which allows the trans-phosphorylation of a subunit of CaMKII by a neighboring kinase, leading to the active state of the system. A combination of all-atom and coarse-grained MD simulations with free energy calculations, led us to reveal an interplay of electrostatic forces exerted by Ca2+/CaM on CaMKII, which initiate the activation process. The highly electrically charged Ca2+/CaM neutralizes basic regions in the linker domain of CaMKII, facilitating its opening and consequent activation. The emerging picture of CaMKIIs behavior highlights the preponderance of electrostatic interactions, which are modulated by the presence of Ca2+/CaM and the phosphorylation of key sites.

biophysics↗