Molecular and Chemical Modulation of NRF2 for Disease Intervention

Abstract

Cells are frequently exposed to endogenous and environmental stressors that pose a threat to homeostatic cellular conditions. In response to such stress, the cell activates an adaptive antioxidant response, which is regulated by the transcription factor NRF2 to mitigate the harmful effects of electrophilic or oxidative species. Pharmacological activation of NRF2 has shown to be effective for preventing the initiation and promotion of cancer, neurodegenerative diseases, and other chronic illnesses, leading to the search for more specific molecules that activate this pathway. Intriguingly, because it is a pro-survival factor, NRF2 is frequently found to be deregulated in many cancer types that are resistant to chemotherapy, calling for the use of NRF2 inhibitors as an adjuvant therapy to enhance the effects of primary chemotherapeutic regimens. In this dissertation, detailed molecular studies have identified a new mechanism by which NRF2 can be aberrantly up-regulated in Type 1 endometrial carcinoma. Additionally, key mechanistic approaches were undertaken to understand the biological consequence of the first NRF2 inhibitor, brusatol. Furthermore, strategic approaches to identify novel chemical modulators of the NRF2 pathway were used, using natural products as a primary source. Assessment of the mechanism of action of biological activity for chemical modulators of the NRF2 pathway was of extreme interest, and rational approaches for the use of these compounds for disease intervention based on disease context will be discussed. Strat-MTM is a synthetic model for transdermal diffusion testing made by EMD Millipore and was marketed as a new skin mimetic membrane. It has been reported to be predictive of diffusion in human skin. Independent researchers had evaluated this membrane and compared it with animal and human skin and other polymeric membranes. Yet, there are not a published research to correlate the animal skin and Strat-MTM based on the amount of drug retained after topical application, which is one of the critical criteria for dermal drug delivery system. In this research, five compounds, with various physiochemical properties, were selected to perform this correlation. Resatorvid, Methyl Para aminobenzoate (M-PABA), Diclofenac sodium, Salicylic acid and hydrocortisone, each one was dissolved in phosphate buffer saline (pH 7.4) in concentrations of 60 ug/ml for resatorvid and 100-120 ug/ ml for others. All experiments were uniform in the setting and made in triplicate. As a conclusion from the results, the number of tested compounds were shorted to reflect the correlation in flux or permeability coefficient between murine skin and Strat-MTM membrane. With exception of M-PABA, there is a trend of correlation with the percentage of drug retained in dermis layers; however, the number of compounds still low to reflect a real correlation.