Medicinal and Pharmaceutical Chemistry 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 …

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 …

The Development Of A Cancer-Targeting Peptide-Drug Conjugate For The Treatment Of Melanoma, Cassandra Dill

Pharmaceutical Sciences (MS) Theses

Cancer is an ongoing global pandemic which has caused a dramatic shift in research priorities. One of the most aggressive and difficult to treat has invariably remained metastatic melanoma. Although encompassing only 4% of overall skin cancer diagnoses, chances for recovery were slim until recent revolutionary development of immunotherapy adding to its regimen spectrum. This is due to its resistance to many standard-of-care treatment methods, along with its relatively high-metastatic potential. Within the past decade, eight new targeted and immune checkpoint inhibitors have gained FDA approval. The median life survival has increased significantly from 9 months to over 2 years …

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 …

Altering The Regiospecificity Of C6 Indole Prenyltransferase Enzymes Towards Drug Development, Ahmed R. Aoun

Pharmaceutical Sciences (MS) Theses

Prenyltransferase (PT) biocatalysts are late-stage tailoring enzymes that modify natural products. PTs catalyze the attachment of prenyl moieties to natural product acceptors using pyrophosphate donors. This prenyl modification in small molecules leads to changes in structural and biological activities. Understanding the structural insights as well as the mechanisms by which PTs function allows us to utilize PTs as a unique approach towards drug development. PriB PT is an example of aromatic PTs that has been characterized previously as a L-tryptophan (L-Trp) C6 C-prenyltransferase (C6-C-PT). Analysis of PriB binding pocket, highlighted key residues that might play an important …