Immunoproteasome and Non-Covalent Inhibition: Exploration by Advanced Molecular Dynamics and Docking Methods

The selective inhibition of immunoproteasome is a valuable strategy to treat autoimmune, inflammatory diseases, and hematologic malignancies. Recently, a new series of amide derivatives as non-covalent inhibitors of the β1i subunit with Ki values in the low/submicromolar ranges have been identified. Here, we investigated the binding mechanism of the most potent and selective inhibitor, N-benzyl-2-(2-oxopyridin-1(2H)-yl)propanamide (1), to elucidate the steps from the ligand entrance into the binding pocket to the ligand-induced conformational changes. We carried out a total of 400 ns of MD-binding analyses, followed by 200 ns of plain MD. The trajectories clustering allowed identifying three representative poses evidencing new key interactions with Phe31 and Lys33 together in a flipped orientation of a representative pose. Further, Binding Pose MetaDynamics (BPMD) studies were performed to evaluate the binding stability, comparing 1 with four other inhibitors of the β1i subunit: N-benzyl-2-(2-oxopyridin-1(2H)-yl)acetamide (2), N-cyclohexyl-3-(2-oxopyridin-1(2H)-yl)propenamide (3), N-butyl-3-(2-oxopyridin-1(2H)-yl)propanamide (4), and (S)-2-(2-oxopyridin-1(2H)-yl)-N,4-diphenylbutanamide (5). The obtained results in terms of free binding energy were consistent with the experimental values of inhibition, confirming 1 as a lead compound of this series. The adopted methods provided a full dynamic description of the binding events, and the information obtained could be exploited for the rational design of new and more active inhibitors

Virtual Screening Strategy and In Vitro Tests to Identify New Inhibitors of the Immunoproteasome

Immunoproteasome inhibition is a promising strategy for the treatment of hematological malignancies, autoimmune diseases, and inflammatory diseases. The design of non-covalent inhibitors of the immunoproteasome beta 1i/beta 5i catalytic subunits could be a novel approach to avoid the drawbacks of the known covalent inhibitors, such as toxicity due to off-target binding. In this work, we report the biological evaluation of thirty-four compounds selected from a commercially available collection. These hit compounds are the outcomes of a virtual screening strategy including a dynamic pharmacophore modeling approach onto the beta 1i subunit and a pharmacophore/docking approach onto the beta 5i subunit. The computational studies were first followed by in vitro enzymatic assays at 100 mu M. Only compounds capable of inhibiting the enzymatic activity by more than 50% were characterized in detail using Tian continuous assays, determining the dissociation constant (K-i) of the non-covalent complex where K-i is also the measure of the binding affinity. Seven out of thirty-four hits showed to inhibit beta 1i and/or beta 5i subunit. Compound 3 is the most active on the beta 1i subunit with K-i = 11.84 +/- 1.63 mu M, and compound 17 showed K-i = 12.50 +/- 0.77 mu M on the beta 5i subunit. Compound 2 showed inhibitory activity on both subunits (K-i = 12.53 +/- 0.18 and K-i = 31.95 +/- 0.81 on the beta 1i subunit and beta 5i subunit, respectively). The induced fit docking analysis revealed interactions with Thr1 and Phe31 of beta 1i subunit and that represent new key residues as reported in our previous work. Onto beta 5i subunit, it interacts with the key residues Thr1, Thr21, and Tyr169. This last hit compound identified represents an interesting starting point for further optimization of beta 1i/beta 5i dual inhibitors of the immunoproteasome

Recent advances in nanotherapeutics for multiple myeloma

Anticancer therapies cannot be included in a one-size-fits-all scenario; it is imperative to adapt therapies to the tumor molecular profile and most importantly to develop target-specific therapeutics. Nanotherapeutics can combine molecular imaging with molecular therapy in order to provide the maximum benefit to patients in terms of disease prevention, identification, and treatment. Nanotechnology applied to therapy provides numerous advantages in diagnostics and in drug delivery, especially for those malignant cells that are diffcult to target or for drugs with poor bioavailability, such as those used for multiple myeloma (MM). This review summarizes the recent advances in the development of nanoparticle-based systems for the treatment of MM, taking into account the methods used for their functionalization, biocompatibility, and anticancer activity

Cysteine Proteases as Validated Targets for the Treatment of Neglected and Poverty-Related Parasitic Diseases

Neglected tropical diseases (NTDs) include 20 diverse infections mainly prevalent in tropical areas that mostly affect disadvantaged communities and women and children [...

Composti antitumorali

L’invenzione riguarda l’uso di derivati derivato dell’1-(4-amino-3,5-dimetilfenil)-3,5-diidro-7,8-etilenediossi-4h-2,3-benzodiazepin-4-one come agenti antitumorali

Potential Role of microRNAs in inducing Drug Resistance in Patients with Multiple Myeloma

The prognosis for newly diagnosed subjects with multiple myeloma (MM) has significantly progressed in recent years. However, most MM patients relapse and after several salvage therapies, the onset of multidrug resistance provokes the occurrence of a refractory disease. A continuous and bidirectional exchange of information takes place between the cells of the microenvironment and neoplastic cells to solicit the demands of cancer cells. Among the molecules serving as messengers, there are microRNAs (miRNA), a family of small noncoding RNAs that regulate gene expression. Numerous miRNAs are associated with drug resistance, also in MM, and the modulation of their expression or activity might be explored to reverse it. In this review we report the most recent studies concerning the relationship between miRNAs and chemoresistance to the most frequently used drugs, such as proteasome inhibitors, steroids, alkylating agents and immunomodulators. The experimental use of antagomirs or miRNA mimics have successfully been proven to counteract chemoresistance and display synergistic effects with antimyeloma drugs which could represent a fundamental moment to overcome resistance in MM treatment

The Impact of Curcumin on Immune Response: An Immunomodulatory Strategy to Treat Sepsis

Primary and secondary immunodeficiencies cause an alteration in the immune response which can increase the rate of infectious diseases and worsened prognoses. They can also alter the immune response, thus, making the infection even worse. Curcumin is the most biologically active component of the turmeric root and appears to be an antimicrobial agent. Curcumin cooperates with various cells such as macrophages, dendritic cells, B, T, and natural killer cells to modify the body’s defence capacity. Curcumin also inhibits inflammatory responses by suppressing different metabolic pathways, reduces the production of inflammatory cytokines, and increases the expression of anti-inflammatory cytokines. Curcumin may also affect oxidative stress and the non-coding genetic material. This review analyses the relationships between immunodeficiency and the onset of infectious diseases and discusses the effects of curcumin and its derivatives on the immune response. In addition, we analyse some of the preclinical and clinical studies that support its possible use in prophylaxis or in the treatment of infectious diseases. Lastly, we examine how nanotechnologies can enhance the clinical use of curcumin