Rational Drug Design of Targeted and Enzyme-Cleavable Vitamin E Analogs as a Neoadjuvant to Chemotherapy: In Vitro and In Vivo Evaluation on Reduction of the Cardiotoxicity Side Effect of Doxorubicin

Targeted Sensitization of Glioblastoma Multiforme Using AAAPT Technology

Glioblastoma Multiforme (GBM) is the most malignant type of all brain tumors. Current GBM treatment options include surgery, followed by radiation and chemotherapy. However, GBM can become resistant to therapy, resulting in tumor recurrence. GBM cells develop resistance to treatments by either downregulating cell death pathways (CD95) or upregulating cell survival pathways (NF-κB (p65)). Healthy tissues can be affected by the increased therapeutic dose. Therefore, it is important to develop a method that can only target GBM tumor cells, thereby reducing the non-specific uptake which will reduce the side effects. Here we demonstrate an application of novel priori activation of apoptosis pathways of tumor technology (AAAPT), which has been used to demonstrate the effect of targeted tumor sensitizers to make chemotherapy work at lower doses in breast, lung and prostate cancers. Treatment of GBM spheroids with AAAPT in 3D PEGDA microwells, showed an increase in cell death, an upregulation of cell death pathways, and a downregulation of cell survival pathways, in comparison to Temozolomide (TMZ), an oral alkylating agent, which is a commonly used chemotherapy in the treatment of GBM. The dose of AAAPT sensitizers may provide a promising method to increase treatment efficacy and reduce off-target toxicity, as an alternative to existing methods which cause significant off-target damage.

Medicago Sativa Defensin1 as a tumor sensitizer for improving chemotherapy: translation from anti-fungal agent to a potential anti-cancer agent

Plant defensins including Medicago Sativa defensin 1 (MsDef1) are cysteine-rich antifungal peptides which are known for potent broad-spectrum antifungal activity against bacterial or fungal pathogens of plants. The antimicrobial activities of these cationic defensins are attributed to their capacity to bind to cell membranes to create potentially structural defects tin the cell membranes to interact with intracellular target (s) and mediates cytotoxic effects. Our earlier work identified Glucosylceramide (GlcCer) of fungus F. graminearum as a potential target for biological activity. Multi-drug resistant (MDR) cancer cells overexpress GlcCer on the surface of plasma membrane. Hence, MsDef1 may have a potential to bind to GlcCer of MDR cancer cells to induce cell death. We have characterized the three-dimensional structure of MsDef1 and the solution dynamics using of 15N-labeled MsDef1 nuclear magnetic resonance (NMR) spectroscopy which showed that GlcCer binds MsDef1 at two specific sites on the peptide molecule. The ability of MsDef1 to permeate MDR cancer cells was demonstrated by measuring the release of apoptotic ceramide in drug resistant MCF-7R cells. It was also shown that MsDef1 activated dual cell death pathways ceramide and Apoptosis Stimulating Kinase ASK1 by disintegrating GlcCer and oxidizing tumor specific biomarker thioredoxin (Trx) respectively. As a result, MsDef1 sensitizes MDR cancer cells to evoke a better response from Doxorubicin, a front-line chemotherapy for triple negative breast cancer (TNBC) treatment. The combination of MsDef1 and Doxorubicin induced 5 to10-fold greater apoptosis in vitro MDR cells MDA-MB-231R compared to either MsDef1 or Doxorubicin alone. Confocal microscopy revealed that MsDef1 facilitates a) influx of Doxorubicin in MDR cancer cells, b) preferential uptake by MDR cells but not by normal fibroblasts and breast epithelial cells (MCF-10A). These results suggest that MsDef1 targets MDR cancer cells and may find utility as a neoadjuvant chemotherapy. Hence, the extension of antifungal properties of MsDef1 to cancer my result in addressing the MDR problems in cancer.