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.

Techn. Hochsch., Diss., 2005--Aachen.

Zugl.: Giessen, Univ., Diss., 2009

8q24.21 is a highly amplified region in cancer and associated with many epithelial cancer such as bladder, breast, colorectal and prostate cancer. The proto-oncogene c-myc is located in this region and surrounded by many lncRNAs genes such as PCAT family, CCAT family, PRNCR1. In this study, we used CRISPR-Cas9 constructs to knock out PCAT1, PRNCR1, CASC8, CASC11 and also the sequences between PCAT1-CASC11 and CASC8-CASC11in the prostate cancer cell PC3. The transfected cells with CRISPR-Cas9 targeting CASC11 gene had less proliferation ability comparing with the transfected cells with CRISPR-Cas9 targeting PCAT1, PRNCR1 or CASC8. The role of CASC11 in cancer progression and development is obscure. In our study, The CASC11 Knockout efficiency was 90% compare to the control cell. Furthermore, the study showed the importance of CASC11 in cell proliferation by significantly decreasing in the forming colonies and the growth rate comparing to the control. Also, MMP2, MMP3 and MMP9 expression levels were detected in the transfected cell by using real time PCR and the result revealed the crucial role for CASC11 in metastasis and migration. The slug and vimentin expression levels were reduced in the transfected and the double transfected clones which indicate the possible role of CASC11 in epithelial mesenchymal transition and cell motility. Taken together, our study revealed that the lncRNA CASC11 plays important roles in prostate cancer progression and metastasis by promoting the cell proliferation and migration.

Genomic complexity in non-Hodgkin’s Diffuse Large B-cell Lymphoma (DLBCL) leads to a treatment failure in ~40% of patients. Activation-Induced Cytosine Deaminase (AID), one of the enzymes involved in generating antibody diversity via class switching recombination (CSR) and somatic hypermutation (SHM) of immunoglobulin (Ig) genes in activated B-cells is one mechanism for the introduction of genomic lesions. In previous studies, AID was shown to preferentially bind to super-enhancer (SE) regions within the genome, but 26% of AID targets were not within the SE regions. The mechanism by which AID interacts with SE elements and its off-target interactions still remains a mystery. Recent evidence suggests that AID may cause genomic lesions in DLBCL via interaction with oncogenes such as MYC and BCL2 resulting in mutations and translocations. Sequences within the MYC promoter contain the four-nucleotide AID target sequence (WRCY) and highly G-rich sequences known to form G-quadruplex DNA secondary structures. We hypothesize that key DNA secondary structures act as recruiting elements for aberrant AID activity at promoters and SEs of key genes involved in the development of DLBCL. Here, we first sought to determine whether known AID DNA targets have the potential to form G-quadruplex DNA secondary structures. The data collected from activated mouse B-cells showed 90% of the AID targets contained sequences that could potentially form G-quadruplexes and the data collected from the human Ramos cell line showed 100% of the sequences had the potential to form G-quadruplexes. To further study our hypothesis we used the techniques circular dichroism (CD) and the electrophoresis motility shift assay (EMSA) to explore the potential interaction between AID and the BCL2 and MYC G-quadruplexes. We observed no significant interactions between AID and these two G-quadruplexes, however further experimentation with different conditions and molecular techniques may show interaction. Additional studies will not only provide key insight into the genomic instability within DLBCL, but will also provide a potential mechanism by which AID is recruited to its DNA targets.