Duchenne Muscular Dystrophy (DMD) is an X-linked recessive neuromuscular disorder caused by mutations or deletions in the dystrophin gene. Utrophin up-regulation therapy is among the various therapeutic strategies that are being investigated to treat DMD. In this strategy utrophin, a dystrophin homologue, is up-regulated along the entire length of the sarcolemma to replace the absent dystrophin protein. Previous studies have revealed that utrophin A expression can be controlled by various transcriptional, post-transcriptional and translational mechanisms and pharmacological modulation of these pathways can stimulate its expression in muscle. In the present study we screened several FDA approved and natural pharmacological compounds that can potentially activate utrophin A expression in muscle. We found that AICAR (AMPK activator) and heparin (p38 activator) were most effective in stimulating utrophin A expression in our C2C12 muscle cell system. Next, we analyzed the effect of combining these activators on utrophin A expression in muscle cells and preclinical mdx mouse model of DMD. Our findings revealed that combinatorial treatment of AICAR and heparin instigated an additive effect on utrophin A expression both in C2C12 muscle cells and mdx mice. Further characterization of treated mdx mice revealed that combinatorial treatment of AICAR and heparin caused improvements in the dystrophic phenotype as indicated by decreased central nucleation, decreased fiber size variability and improved sarcolemmal integrity in dystrophic muscle. Together these findings established that combinatorial treatment of AICAR and heparin ameliorates the dystrophic phenotype in mdx mice and may serve as an effective therapeutic strategy for DMD.

Chronic Myelogenous Leukemia (CML) is a blood cancer that arises when hematopoietic cells acquire an abnormal protein known as BCR-ABL. Current therapies for CML include drugs that inhibit BCR-ABL. However, these drugs only suppress the disease and do not cure it. One reason is that BCR-ABL drugs fail to kill the primitive population of CML cells, referred to as leukemia stem cells (LSCs), which are responsible for initiating and propagating CML. Since LSCs are not killed, the cancer is not cured and many affected patients eventually relapse. Recent studies suggest that LSCs are protected from current therapies by the bone marrow micro-environment where they reside. There, cytokine signaling molecules are present, which mediate processes that protect LSCs from BCR-ABL drugs. The stem cell factor (SCF) is one of these signaling molecules. It activates the receptor c-Kit located on the surface of LSCs, and this activation in turn allows proliferating LSCs to resist BCR-ABL drugs, even without prior exposure to these drugs, i.e., innate resistance is observed. In this thesis, the mechanism of this innate resistance is investigated, so that a suitable treatment strategy can be developed. To this end, a co-agent approach based on synthetic antibodies (sABs) is proposed to inhibit the receptor c-Kit, with the goal of disrupting its activation by the ligand SCF. This disruption should in turn block the SCF-mediated innate resistance, thus potentially restoring BCR-ABL drug apoptotic activity. The method for this disruption involves targeting the c-Kit structural susceptibility. Specifically, the sABs are designed via antibody phage display technology to target the D1–D2–D3 domains representing the SCF binding sites, hence preventing downstream pathway activation. The hypothesis is that, by blocking the SCF-mediated innate resistance, a suitable combination of such an sAB co-agent and a BCR-ABL drug should be conducive to suppressing LSCs, thereby providing a potential means to improve CML treatment. In addition, to assess the performance of the proposed treatment strategy, a set of in vitro tests is conducted, focusing on performance behaviors such as cell binding, cell death, and the progenitor inhibition. The experimental results support the hypothesis that the proposed combinatorial strategy is indeed a promising approach to mitigate the innate resistance, thus restoring BCR-ABL drug apoptotic activity.