Pharmaceutics and Drug Design Commons^™

Analyzing Functional Interactions Of Designed Peptides By Nmr Spectroscopy, Wonsuk Choi

Pharmaceutical Sciences (MS) Theses

The development of small peptide-based therapeutics can be accelerated by the knowledge of relationships between the peptide structure and its functional interactions. Here, we report the analysis of two groups of synthetic peptides designed for two applications – broad bactericidal action and inhibition of protein-protein interactions in human cells. Novel amphiphilic peptides designed for antibacterial application incorporated arginine as cationic amino acids and non-natural amino acids that have aromatic side chains with similar hydrophobic properties as tryptophan. The interaction of lead cyclic peptides and their linear analogs with a phospholipid bilayer mimicking a bacterial membrane was studied using nuclear magnetic …

The Development Of A Novel Peptide-Drug Conjugate For Treating Triple-Negative Breast Cancer, Phi-Phung Than

Pharmaceutical Sciences (MS) Theses

Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype with poor prognosis and is difficult to treat. A diagnosis of TNBC means that the three most common types of receptors known to fuel most breast cancer growth–estrogen, progesterone, and HER2– are not present in the cancer tumors. Since the tumor cells lack necessary receptors, common treatments like hormone therapies and targeted HER2 drugs are ineffective. The use of chemotherapies in treating TNBC is an effective option instead. However, chemotherapies are not selective, thus they cause severe side effects such as cardiotoxicity, myelosuppression, alopecia and gastrointestinal problems. A peptide-drug conjugate …

Cyclic And Linear Cell-Penetarating Peptides Composed Of Tryptophan (Ww) And Arginine (Rr) Residues As Molecular Transporters, Lois Kim

Pharmaceutical Sciences (MS) Theses

The cell membrane has polar and negative charged characteristics and separates the inside of cells from the outside environment, and only allows small molecules to go into the cell to protect them from toxic substances. However, cell membrane characteristics make it difficult for polar and negatively-charged molecules to interact and penetrate the membrane. The delivery of cell impermeable compounds, such as phosphopeptides and siRNA, across the cell membrane remains a challenge. Previous studies in Dr. Parang’s laboratory have shown that cyclic peptides composed of tryptophan (W) and arginine (R) amino acids [WR]₅ have higher cellular uptake than the corresponding …

Effects Of Nnos Inhibitors On Melanoma-Induced Immunosuppression, Kate Alison Lozada

Pharmaceutical Sciences (MS) Theses

The incidence of cutaneous melanoma (CM) rises despite advances in immunotherapy and targeted therapy. Studies have shown that interferon-gamma (IFN-γ), a pro-tumorigenic cytokine in CM, induces the expression of programmed death-ligand 1 (PD-L1), leading to the escape of melanoma cells from immunosurveillance. Our previous study suggests that neuronal nitric oxide synthase (nNOS)-mediated nitric oxide (NO) signaling is crucial for melanoma progression and forms a mechanistic rationale behind nNOS inhibition as a novel treatment strategy for CM. An additional study demonstrated that IFN-γ interacts with nNOS signaling in melanoma and novel nNOS inhibitors (nNOSi) effectively diminished the induction of PD-L1 post …

Modulation Of Antibacterial Activity And Cytotoxicity In Amphipathic Cyclic Peptide [R4w4] Using Histidine Substitution, Ryan Stueber

Pharmaceutical Sciences (MS) Theses

Antibiotics have been the gold standard frontline defense against bacterial infections for decades. At the same time, these infecting bacteria have continued to evolve to resist developed antibiotics in an almost endless cycle. As such, we aim to take an alternative approach utilizing antimicrobial peptides (AMPs) as a means to end this cycle. [R4W4] is among known AMPs that demonstrated antimicrobial activity against methicillin-resistant staphylococcus aureus (MRSA) with a minimum inhibitory concentration (MIC) of 2.67 μg/mL. This peptide had notably effective antimicrobial activity, especially relative to linear (R4W4). However, it displayed a concerning level of cytotoxicity; eliciting a human embryonic …

Amphiphilic Cell-Penetrating Peptides Containing Natural And Unnatural Amino Acids As Drug Delivery Tools And Antimicrobial Agents, David Salehi

Pharmaceutical Sciences (MS) Theses

Cell-penetrating peptides containing arginine as positively charged residues and tryptophan or diphenylalanine as hydrophobic residues were synthesized. The synthesis was accomplished through the Fmoc solid-phase peptide synthesis in the presence of HBTU and DIPEA. The side-chain protected linear peptides were cleaved from the resin and cyclized in the presence of DIC and HOAt in the solution phase overnight. MALDI-TOF mass spectrometry was used to characterize the peptides.

The cytotoxicity of the synthesized peptides was determined in CCRF-CEM (human, lymphoblast peripheral blood), and HEK-293 (human, embryonic epithelial kidney healthy) cells using the MTS assay. A concentration of 10 µM was found …

Hybrid Cyclic/Linear Peptides In A Multi-Component Lipid Structure As A Sirna Delivery System, Abdulaziz Alasmari

Pharmaceutical Sciences (MS) Theses

Delivering siRNA is challenging due to many obstacles, such as extremely short in vivo half-life, rapid elimination via glomerular filtration, and inability to cross cell membranes due to the hydrophilic and negatively-charged nature. Thus, a delivery system is needed to deliver the siRNA into the cells by crossing the negatively-charged phospholipid cell membrane. The goal of this project was to design hybrid cyclic-linear peptides as siRNA delivery system. We designed and synthesized hybrid cyclic-linear peptides [R5K]W5, [R6K]W6, and [R5K]W7 containing positively-charged arginine residues attached to hydrophobic tryptophan chains for more efficient interaction with siRNA and to improve siRNA internalization into …

The Development Of Novel Apurinic/Aprymidinic Endonuclease/Redox-Factor 1 Inhibitors For The Treatment Of Human Melanoma, Bella Sharifi

Pharmaceutical Sciences (MS) Theses

Apurinic/apyrimidinic DNA repair endonuclease-1 (APE1), first recognized as an important DNA excision repair enzyme, is also known as Redox Factor-1 (Ref-1) involved in the activation of many nuclear transcription factors in both redox-dependent and independent manner. It has been well-documented that the overexpression of APE/Ref-1 contributes to the development of chemo-resistance and is associated with tumor progression in many human malignancies [1].

Our previous study in melanoma demonstrated that the development of novel inhibitors targeting the redox regulation domain of APE/Ref-1 is a promising strategy for melanoma treatment. To date, limited successes have been reported in developing novel …