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Dna Methylation-Based Epigenetic Biomarkers In Cell-Type Deconvolution And Tumor Tissue Of Origin Identification, Ze Zhang

Dartmouth College Ph.D Dissertations

DNA methylation is an epigenetic modification that regulates gene expression and is essential to establishing and preserving cellular identity. Genome-wide DNA methylation arrays provide a standardized and cost-effective approach to measuring DNA methylation. When combined with a cell-type reference library, DNA methylation measures allow the assessment of underlying cell-type proportions in heterogeneous mixtures. This approach, known as DNA methylation deconvolution or methylation cytometry, offers a standardized and cost-effective method for evaluating cell-type proportions. While this approach has succeeded in discerning cell types in various human tissues like blood, brain, tumors, skin, breast, and buccal swabs, the existing methods have major …

Identification Of Novel Biosynthetic Gene Clusters Encoding For Polyketide/Nrps-Producing Chemotherapeutic Compounds From Marine-Derived Streptomyces Hygroscopicus From A Marine Sanctuary, Hannah Ruth Flaherty

Honors Theses and Capstones

Nearly one out of six deaths in 2020, around ten million people, were caused by cancer, making it a leading cause of death worldwide (WHO, 2022). This major public health issue, in addition to the rise of multidrug-resistant (MDR) pathogens, provides a high demand for the discovery of new pharmaceutical drugs to be used clinically to treat these conditions. The Streptomyces genus accounts to produce 39% of all microbial metabolites currently approved for human health, indicating its potential as an important species to study for antimicrobial and anticancer agents. The long linear genome of Streptomyces contains specialized sequences known as …

Mixture Model Approaches To Integrative Analysis Of Multi-Omics Data And Spatially Correlated Genomic Data, Ziqiao Wang

Dissertations & Theses (Open Access)

Integrative genomic data analysis is a powerful tool to study the complex biological processes behind a disease. Statistical methods can model the interrelationships of the involved gene activities through jointly analyzing multiple types of genomic data from different platforms (vertical integration), or improve the power of a study through aggregating the same type of genomic data across studies (horizontal integration). In this dissertation, we propose statistical methods and strategies for integrative multi-omics data in association analysis of disease phenotypes, with an emphasis on cancer applications.

We develop a new strategy based on horizontal integration by leveraging publicly available datasets into …

Investigation Of Proliferation Suppressors In Genetic Fitness Screens, Walter Frank Lenoir Iv

Dissertations & Theses (Open Access)

Innovation of CRISPR gene-editing technology has provided scientists genome manipulation tools that allowed rapid advancement of scientific capabilities and thus improved our ability to systematically study mammalian genetic functional profiles. Genome-wide CRISPR knockout screens conducted in collections of human cell lines can knock out genes at multiple loci, and have provided new insights into functional roles for independent genes. This method has launched massive efforts in looking across genetic backgrounds for context specific genetic vulnerabilities within cancer. Much of the research effort thus far has been spent on optimizing phenotype distinctions between essential, genes required for cell fitness, and non-essential, …

Statistical Methods For Resolving Intratumor Heterogeneity With Single-Cell Dna Sequencing, Alexander Davis

Dissertations & Theses (Open Access)

Tumor cells have heterogeneous genotypes, which drives progression and treatment resistance. Such genetic intratumor heterogeneity plays a role in the process of clonal evolution that underlies tumor progression and treatment resistance. Single-cell DNA sequencing is a promising experimental method for studying intratumor heterogeneity, but brings unique statistical challenges in interpreting the resulting data. Researchers lack methods to determine whether sufficiently many cells have been sampled from a tumor. In addition, there are no proven computational methods for determining the ploidy of a cell, a necessary step in the determination of copy number. In this work, software for calculating probabilities from …

Investigating The Role Of Cd109 In Pancreatic Ductal Adenocarcinoma, Mennatallah Shaheen

Dissertations & Theses (Open Access)

Pancreatic Ductal Adenocarcinoma (PDAC) is the 3rd leading cause of cancer death in the US. We performed loss of function genomic screening on a cohort of four patient derived PDAC cell populations and our data shows a cell surface receptor CD109 to be a common vulnerability, the biologic role of which in PDAC is yet unstudied and largely unknown. We hypothesized that CD109 expression provides PDAC cells with a survival advantage, and promotes cancer progression through activation of downstream signaling. We believe therefore that targeting CD109 could improve PDAC patients’ survival. Here we report that CD109 plays a role in …

Identification Of Cell Signaling Pathway Regulated By Micrornas In Cancer Cells Using A Systems Biological Approach, Sangbae Kim

Dissertations & Theses (Open Access)

MicroRNAs (miRNAs) are single-stranded, non-coding RNA molecules that regulate gene expression via imperfect binding of the miRNA to specific sites in the 3' untranslated region of the mRNAs. Because prediction of miRNA targets is an essential step for understanding the functional roles of miRNAs, many computational approaches have been developed to identify miRNA targets. However, identifying targets remains challenging due to the inherent limitation of current prediction approaches based on imperfect complementarity between miRNA and its target mRNAs. To overcome these current limitations, we developed a novel correlation-based approach that is sequence independence to predict functional targets of miRNAs by …

Discovery And Elucidation Of The Fgfr3-Tacc3 Recurrent Fusion In Glioblastoma, Brittany C. Parker Kerrigan

Dissertations & Theses (Open Access)

Fusion genes occur due to chromosomal instability where two previously separate genes rearrange and fuse together, forming a hybrid gene. The first fusions were reported in leukemias; however, with the advent of more powerful sequencing technologies, fusions have recently been reported in several solid tumors. Using next-generation deep sequencing approaches, we discovered a fusion gene connecting the fibroblast growth factor receptor 3 (FGFR3) gene to the transforming coiled-coil containing protein 3 (TACC3) gene in glioblastoma multiforme. The fusion occurred in 8.3% of patient samples, but not in low grade or normal samples. FGFR3-TACC3 produced an in-frame …