2022 VCOM Research Retreat Program

ABSTRACTS

Characterizing Molecular Mechanisms that Mutant Proteins Promote Cancer Progression Presenter: Lin Kang, PhD Co-Authors: Md Saqline Mostaq; Amanda Raphael; Celine Asbury*; Anish Gupta; Yong-Yu Liu, MD, Phd Mutant proteins of cancer-addicted genes (such as TP53 and KRAS) promote cancer progression in metastases and cause cancer resistance to treatments. However, it is still unclear how the expression of mutant proteins is upregulated and further promotes the enrichment of cancer stem cells in tumors under chemotherapy. In response to the challenges of anticancer drugs, increased ceramide glycosylation catalyzed by glucosylceramide (GCS) confers cancer drug resistance and enriches cancer stem cells. We established UGCG knock-out cell models and characterized the correlation of ceramide-glycosylation to tumor progression. The Human UGCG gene that encodes GCS, a limiting enzyme catalyzing the first reaction of ceramide glycosylation, was knocked out in colorectal cancer cell lines of WiDr (TP53 R273H+/+) and LS1747 (KRAS G12A+/-) via CRISP/cas9 gene editing. We found that knock-out of UGCG significantly decreased GCS activity, the EC50 values of oxaliplatin, and tumorgenicity of WiDr/UGCG-KO cancer cells, and further re-sensitized tumor generated from WiDr/UGCG-KC cells response to oxaliplatin treatments. Based on single nucleus-RNA sequencing (snRNA-seq), we will be able to characterize various cell populations during the propagation of cancer stem cells in tumors under chemotherapy. Further assessment and genomic analyses of snRNA-seq with typical RNA-seq of tumors will help us to characterize molecular mechanisms that regulate the cancerous pluripotency, formation, and differentiation of cancer stem cells from tumors under chemotherapy. Colorectal cancer (CRC) is the fourth most common type of cancer and the second leading cause of cancer-related deaths in the United States. One pathway that is heavily implicated in CRC is NF-kB, a master transcriptional regulator of genes related to proliferation, survival, immunity, and inflammation. Previous studies have demonstrated the anti-inflammatory and anti-neoplastic role of the canonical NF-kB signaling pathway in CRC. NF-kB is extensively down regulated in CRC of both mice and humans. However, relatively little is known about the non-canonical NF-kB signaling cascade (activation of Nik). To further understand NF-kB/Nik involvement in colon cancer development and progression, we will grow murine intestinal organoids extracted from wild-type (Nikloxp), Nik-/-, Nikloxp/Villiancre, and Villiancre mice and characterize their growth and development in comparison with WT. Our research hopes to further characterize this aggressive and deadly disease. We hypothesize that loss of non-canonical NFκB signaling attenuates stem cell regeneration of the epithelial cell barrier and/or inhibits cell death in mature epithelial cells in the colon. We further postulate that either of these events is significant contributor to the progression of colorectal cancer and may contribute to tumorigenesis through either a stem cell or enterocyte-dependent mechanism. We hope to further identify the cell composition and 3D architecture of these NF-kB low organoids to better understand how NF-kB is implicated in the development of CRC Role of Noncanonical NF-kB Signaling in the Development of Intestinal Cell Subpopulations Presenter: Stephan Brown, MD, PhD Co-Authors: Creighton Kellogg*; Mandy Stallard*; Katherine Hanson, MS; Holly Morrison*; Irving Allen, PhD

*VCOM Student