Enhancement of Binding Affinity of Folate to Its Receptor by Peptide Conjugation

Abstract

(1) Background: The folate receptor (FR) is a target for cancer treatment and detection. Expression of the FR is restricted in normal cells but overexpressed in many types of tumors. Folate was conjugated with peptides for enhancing binding affinity to the FR. (2) Materials and Methods: For conjugation, folate was coupled with propargyl or dibenzocyclooctyne, and 4-azidophenylalanine was introduced in peptides for “click” reactions. We measured binding kinetics including the rate constants of association (ka) and dissociation (kd) of folate-peptide conjugates with purified FR by biolayer interferometry. After optimization of the conditions for the click reaction, we successfully conjugated folate with designed peptides. (3) Results: The binding affinity, indicated by the equilibrium dissociation constant (KD), of folate toward the FR was enhanced by peptide conjugation. The enhanced FR binding affinity by peptide conjugation is a result of an increase in the number of interaction sites. (4) Conclusion: Such peptide-ligand conjugates will be important in the design of ligands with higher affinity. These high affinity ligands can be useful for targeted drug delivery system.

The interactions of folate with the enzyme furin: a computational study

“…Thus, intermolecular nonpolar solvation and electrostatic interactions are the main forces involved in the binding of drugs with furin structure. The binding affinity (dissociation constant ( K d )) of folate for human folate receptor via isothermal titration calorimetry measurements has been obtained to be ∼10 × 10 −12 M. 34 Also, the binding affinity of folate receptor toward folate measured by biolayer interferometry was ∼1.14 × 10 −9 M. 35 Folic acid binding to folate receptor determined by saturation radioligand-binding assay has been examined to be ∼1.90 × 10 −10 M. 36 The binding free energy of protein-ligand complex formation, can be associated with the dissociation constant through equation, in which T is the absolute temperature, R is the ideal gas constant, C 0 is generally set to 1 with the moles per liter dimension and is accordingly dimensionless. By using this equation, binding free energies of folate for human folate receptor were determined to be −15.05, −12.23, and −13.30 kcal mol −1 , experimentally.…”

Preparation of Biphenyl-Conjugated Bromotyrosine for Inhibition of PD-1/PD-L1 Immune Checkpoint Interactions

“…The results of this study advance our understanding of how small molecule compounds could be rationally designed to inhibit PD-1/PD-L1 interactions with high affinity. In silico docking simulations have typically shown that target proteins have stable binding pockets during ligand binding, even allowing for some local flexibility of the side chains within the pockets [37,44]. In that scenario, binding scores generally correlate well with experimentally determined inhibitor activity [45].…”

“…The docking simulation software ICM 3.8-7 [33] was used to investigate the binding modes of X and amino-Xs to the PD-L1 homodimer complexed with BMS-8 (PDB ID: 5J8O) [31]. We performed docking without template docking [37] or introducing flexibility [37] to avoid over-fitting of the ligands into the pocket. The docking simulation supposed Monte Carlo pseudo-Brownian motion [46].…”

“…Because an amino and carboxyl group included in X, it could be conjugated to various amino acids. [36,37]. During the procedures, we employed in silico simulation and IC50 assay to reveal molecular mechanism of the inhibition.…”

A Redox-Activatable and Targeted Photosensitizing Agent to Deliver Doxorubicin for Combining Chemotherapy and Photodynamic Therapy

“…Chemotherapy drugs have a long history in cancer treatment, since they can inhibit tumor cells proliferation and induce apoptosis. , However, due to the lack of targeting of chemotherapy drugs, they can not selectively kill tumor cells. Therefore, we need to target release of chemotherapy drugs to reduce their toxic and side effects on normal tissues. − Folic acid (FA) receptors are overexpressed on the surface of many tumor cells. − In recent years, researchers have often coupled FA with anticancer drugs to target tumor cells to achieve the targeting function of anticancer drugs. , Moreover, stimulation-responsive nano drug carriers (pH conditions, reductive environment, temperature, enzyme, etc.) have become a research hotspot in recent years, which take advantage of the differences between the microenvironments of tumor cells and normal cells to selectively release anticancer drugs in tumor cells. − Finally, loading anticancer drugs into FA-modified stimulation-responsive nano drug carriers for administration can reduce the side effects of anticancer drugs, achieve controlled release of anticancer drugs at the target, and improve the therapeutic effect of diseases …”