Doctor of Philosophy, The Ohio State University, 2023, Pharmaceutical Sciences

Osteosarcoma (OS) is the most common malignant primary bone tumor in pediatric patients. Therapeutic target identification in osteosarcoma has been extremely challenging due to the high degree of heterogeneity in osteosarcoma genetic profile and the lack of specific oncogenic driver genes. Despite the great research efforts, the treatment and survival outcomes for osteosarcoma patients have stagnated over the past 30 years, and osteosarcoma remains a lethal cancer due to metastasis and development of resistance to current chemotherapies. Study of chemo-resistance and identification of novel targets are therefore critical to better understand osteosarcoma chemo-resistance mechanisms and ultimately lead to new therapies. In the hope of providing an innovative angle for osteosarcoma study, we first performed a comprehensive multiplatform analysis on osteosarcoma tumors, including somatic copy number alteration, gene expression and methylation, and identified three molecularly distinct and clinically relevant subtypes for osteosarcoma. Previously unappreciated osteosarcoma-type-specific features were revealed based on the subgrouping, providing insights into refining osteosarcoma therapy and relationships to other types of cancer. Additionally, a CRISPR functional knockout screen is an ideal new strategy to address the genetic complexity of osteosarcoma. The CRISPR/Cas9 gene editing system with customized libraries of guide RNAs (gRNAs) can be used to test the contribution of each individual gene to osteosarcoma therapy resistance on a genome-wide scale. By comparing the differences in the abundance of gRNAs between the control and phenotyped samples, the genes responsible for the observed phenotype can be identified. Genome-wide CRISPR screen with low-dose drug treatment was conducted on the selected osteosarcoma cell line SaOS2 to identify the genes that are essential for osteosarcoma cell proliferation under different drug treatments. The CRISPR screen, together wi (open full item for complete abstract)

Committee: Moray Campbell (Committee Member); Ryan Roberts (Committee Member); Jeffrey Parvin (Committee Member); Li Lang (Advisor) Subjects: Bioinformatics; Biology; Pharmaceuticals; Pharmacy Sciences