Myc is a powerful oncogene frequently deregulated in cancer yet deregulated Myc alone does not lead to cellular transformation due to the intrinsic safety mechanism of deregulated Myc potentiating apoptosis. The mechanism by which Myc potentiates apoptosis remains unclear, however, because the regions of Myc essential for apoptosis are also required for Myc to function as a regulator of gene transcription, it is thought that Myc’s role in apoptosis is a function of its regulation of an apoptotic genetic program. We hypothesize that under apoptotic conditions, Myc differentially binds and/or regulates a specific cohort of genes to potentiate apoptosis. The foremost approach to addressing this hypothesis is the employment of ChIP-chip coupled with expression microarray analyses. Here, using the MCF10A breast epithelial and SHEP neuroblastoma cell lines, we developed and characterized two independent human systems for subsequent ChIP-chip and expression array analyses to elucidate the genetic program of Myc-potentiated apoptosis.

Cullin 7 (Cul7) is a member of the cullin protein family that is emerging as a complex anti-apoptotic player in tumourigenesis. We hypothesize that by determining the mechanism through which Cul7 can protect against specific forms of cell death, we will uncover novel molecular pathways important in cancer. We aimed to address mechanism by evaluating which domains within Cul7 are important for its activity. Thus, we have introduced mutations in each of the Cul7 domains and asked whether any of these has an effect on the ability of Cul7 to inhibit cell death. To be able to detect even subtle affects of mutation, we required that mutants be assessed in appropriate experimental systems where ectopic wild-type Cul7 could robustly inhibit death compared to vector controls. We screened multiple cell lines and agonists, and have now indentified conditions in U2OS and SHEP cell lines in which our mutants can be evaluated.

Effective therapeutics are urgently needed to improve the treatment and survival of cancer patients and we believe that targeting the MYC oncogene would fill this gap. Our strategy to achieve this goal involves the design of minimalist hybrid protein inhibitors (MHP) - 25-75 amino acid proteins composed of subdomains of known transcription factor families to generate hybrids that act as structural competitive inhibitors of the Myc/Max:DNA E-box interaction. We have established cell systems, reagents and assays using our prototype MHP, ME47 to evaluate the biological effectiveness of this putative inhibitor as well as subsequently designed MHPs using cell-based proliferation and transformation assays. Omomyc was included as a proof-of-concept control to optimize our systems and gauge the performance of ME47. This research demonstrates for the first time that ME47 exerts desirable biological effects in human cells lines and provides support for the validity of our MHP strategy thus warranting further investigation.

Myc is a powerful oncogene frequently deregulated in cancer yet deregulated Myc alone does not lead to cellular transformation due to the intrinsic safety mechanism of deregulated Myc potentiating apoptosis. The mechanism by which Myc potentiates apoptosis remains unclear, however, because the regions of Myc essential for apoptosis are also required for Myc to function as a regulator of gene transcription, it is thought that Myc’s role in apoptosis is a function of its regulation of an apoptotic genetic program. We hypothesize that under apoptotic conditions, Myc differentially binds and/or regulates a specific cohort of genes to potentiate apoptosis. The foremost approach to addressing this hypothesis is the employment of ChIP-chip coupled with expression microarray analyses. Here, using the MCF10A breast epithelial and SHEP neuroblastoma cell lines, we developed and characterized two independent human systems for subsequent ChIP-chip and expression array analyses to elucidate the genetic program of Myc-potentiated apoptosis.

Cullin 7 (Cul7) is a member of the cullin protein family that is emerging as a complex anti-apoptotic player in tumourigenesis. We hypothesize that by determining the mechanism through which Cul7 can protect against specific forms of cell death, we will uncover novel molecular pathways important in cancer. We aimed to address mechanism by evaluating which domains within Cul7 are important for its activity. Thus, we have introduced mutations in each of the Cul7 domains and asked whether any of these has an effect on the ability of Cul7 to inhibit cell death. To be able to detect even subtle affects of mutation, we required that mutants be assessed in appropriate experimental systems where ectopic wild-type Cul7 could robustly inhibit death compared to vector controls. We screened multiple cell lines and agonists, and have now indentified conditions in U2OS and SHEP cell lines in which our mutants can be evaluated.

Effective therapeutics are urgently needed to improve the treatment and survival of cancer patients and we believe that targeting the MYC oncogene would fill this gap. Our strategy to achieve this goal involves the design of minimalist hybrid protein inhibitors (MHP) - 25-75 amino acid proteins composed of subdomains of known transcription factor families to generate hybrids that act as structural competitive inhibitors of the Myc/Max:DNA E-box interaction. We have established cell systems, reagents and assays using our prototype MHP, ME47 to evaluate the biological effectiveness of this putative inhibitor as well as subsequently designed MHPs using cell-based proliferation and transformation assays. Omomyc was included as a proof-of-concept control to optimize our systems and gauge the performance of ME47. This research demonstrates for the first time that ME47 exerts desirable biological effects in human cells lines and provides support for the validity of our MHP strategy thus warranting further investigation.

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 1996. / Vita. Includes bibliographical references (leaves [85]-98).

Thèse (M.Sc.)--Université Laval, 2005. / Titre de l'écran-titre (visionné le 28 mars 2007). Bibliogr.

Thèse (Ph.D.)--Université Laval, 2002. / Bibliogr.: f. 242-282. Publié aussi en version électronique.