Nucleic Acids, Nucleotides, and Nucleosides Commons^™

Great Expectations: Phosph(On)Ate Prodrugs In Drug Design—Opportunities And Limitations, Victoria Yan

Dissertations & Theses (Open Access)

Phosphate and phosphonates are chemical moieties with historical precedence in anticancer and antiviral nucleotide analogues. Synchronous to modern efforts identifying novel therapeutic targets in cancer, such chemical moieties are being investigated in the design of novel inhibitors with antineoplastic potential. A central challenge to the delivery of phosph(on)ate-containing drugs is their anionic character at physiological pH, which portends poor membrane permeability. This limitation has been successfully overcome through the use of prodrugs. When attached to the phosph(on)ate moiety, prodrugs mask the negative charge and easily enable cell permeability. Upon cellular entry, the promoieties are enzymatically or environmentally cleaved to unveil …

Evaluating The Therapeutic Efficacy Of Grb2 Inhibition In Ovarian Malignancies, Olivia Lara

Dissertations & Theses (Open Access)

Purpose: Adaptor proteins such as growth factor receptor-bound protein-2 (Grb2) play important roles in cancer cell signaling. In the present study, we examined the biological effects of liposomal antisense oligodeoxynucleotide that blocks Grb2 expression (L-Grb2) in ovarian cancer models.

Experimental Design: Murine orthotopic models of ovarian cancer (OVCAR5 and SKOV3ip1) were used to study the biological effects of L-Grb2 on tumor growth. In vitro experiments (cell viability assay, Western blot analysis, siRNA transfection, and reverse phase protein array) were carried out to elucidate the mechanism and potential predictors of tumor response to L-Grb2.

Results: Treatment with L-Grb2 decreased tumor growth …

The Regulation Of Dna Methylation In Mammalian Development And Cancer, Nicolas Veland

Dissertations & Theses (Open Access)

DNA methylation is an essential epigenetic modification in mammals, as it plays important regulatory roles in multiple biological processes, such as gene transcription, maintenance of chromosomal structure and genomic stability, genomic imprinting, retrotransposon silencing, and X-chromosome inactivation. Dysregulation of DNA methylation is associated with various human diseases. For example, cancer cells usually show global hypomethylation and regional hypermenthylation, which have been implicated in genomic instability and tumor suppressor silencing, respectively. Although great progress has been made in elucidating the biological functions of DNA methylation over the last several decades, how DNA methylation patterns and levels are regulated and dysregulated is …

Targeting Oncogenic Mirnas With Small Molecules For Breast Cancer Therapy, Paloma Del C. Monroig

Dissertations & Theses (Open Access)

The crucial role of microRNAs (miRNAs) in cancer pathobiology has driven the introduction of new drug development approaches such as miRNA inhibition. In order to advance miRNA-therapeutics, there is a need to develop screening strategies that can target tumors in a specific way. Small molecule inhibitors represent an attractive approach to pursue this. However, the absence of molecular structures for most of the miRNAs makes it very difficult to predict which inhibitors can bind to them. Herein we designed a strategy to screen for small molecules by assesing whether they could directly bind/ interact with miR-10b/miR-21. As part of our …

Design, Synthesis And Development Of Transporter Targeting Agents For Image-Guided Therapy And Drug Delivery, Ning Tsao

Dissertations & Theses (Open Access)

The purpose of this study was to design, synthesize and develop novel transporter targeting agents for image-guided therapy and drug delivery. Two novel agents, N4-guanine (N4amG) and glycopeptide (GP) were synthesized for tumor cell proliferation assessment and cancer theranostic platform, respectively. N4amG and GP were synthesized and radiolabeled with ^99mTc and ⁶⁸Ga. The chemical and radiochemical purities as well as radiochemical stabilities of radiolabeled N4amG and GP were tested. In vitro stability assessment showed both ^99mTc-N4amG and ^99mTc-GP were stable up to 6 hours, whereas ⁶⁸Ga-GP was stable up to 2 hours. Cell culture studies …

Chemosensitization Of Hepatocellular Carcinoma To Gemcitabine By Non-Invasive Radiofrequency Field-Induced Hyperthermia, Mustafa Raoof

Dissertations & Theses (Open Access)

Gemcitabine is a potent nucleoside analogue against solid tumors however drug resistance rapidly emerges. Removal of gemcitabine incorporated in the DNA by repair mechanisms could potentially contribute to resistance in chemo-refractory solid tumors. In this study, we evaluated homologous recombination repair of gemcitabine-stalled replication forks as a potential mechanism contributing to resistance. We also studied the effect of hyperthermia on homologous recombination pathway to explain the previously reported synergy between gemcitabine and hyperthermia. We found that hyperthermia degrades and inhibits localization of Mre11 to gemcitabine-stalled replication forks. Furthermore, gemcitabine-treated cells that were also treated with hyperthermia demonstrate a prolonged passage …