The Development of Novel Apurinic/Aprymidinic Endonuclease/Redox-factor 1 Inhibitors for the Treatment of Human Melanoma

<p>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 [<a href="https://www.ncbi.nlm.nih.gov/pubmed/28852018" target="_blank" title="Ape1 guides DNA repair pathway choice that is associated with drug tolerance in glioblastoma.">1</a>]. </p> <p>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 APE/Ref-1 inhibitors for cancer treatment. Utilizing a structure-based approach, our study identified and characterized small molecular inhibitors of APE/Ref-1. First, <em>N</em>-terminally truncated APE/Ref-1 protein lacking the first 40 amino acid residues (∆40APE-1^wt) was cloned into the pGEX-6P1 vector to express the GST-∆40APE-1^wtprotein. After cleavage of GST-tag, the concentrated ∆40APE-1^wt protein was subjected to protein crystallization study. We have successfully diffracted ∆40APE-1^wt crystals and collected data with a resolution of 1.57Å. The crystal structure was further determined by molecular replacement in Molrep using the already available human APE-1 structure (PDB: 5CFG). For the first time, we observed the dimerization of APE/Ref-1 protein formed under oxidative conditions, which may contribute to the redox regulation of APE/Ref-1. Such structural transformation of APE/Ref-1 protein under distinct redox conditions may pave the way for future drug development and optimization. The binding affinity of the candidate compounds with ∆40APE-1^wtprotein was also determined using Surface Plasmon Resonance (SPR), and the <em>Ki</em> values were analyzed. One of the potent inhibitors developed by our group by structure-based approach, exhibited promising anti-melanoma activities both <em>in vitro</em> and <em>in vivo</em>. Future studies on the structure-activity association are warranted. </p>

Name thesis:degree_name

Master of Science (MS)

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Pharmaceutical Sciences

Year dc:date.available

2019

Author dc:creator

• Sharifi, Bella

Contributors dc:contributor

• Sun Yang
• Miao Zhang
• Keykavous Parang
• Kamaljit Kaur

• Structural Biology
• Protein Crystallography
• Drug Design Delivery
• Medical Cell Biology
• Medical Molecular Biology
• Medical Pharmacology
• Other Pharmacy and Pharmaceutical Sciences
• Pharmaceutics and Drug Design
• Skin and Connective Tissue Diseases

Repository record dc:identifier

https://digitalcommons.chapman.edu/pharmaceutical_sciences_theses/7

OAI identifier oai:identifier

oai:digitalcommons.chapman.edu:pharmaceutical_sciences_theses-1007