DOI
https://doi.org/10.25772/GMSY-1M48
Author ORCID Identifier
https://orcid.org/0000-0003-2918-5486
Defense Date
2025
Document Type
Thesis
Degree Name
Master of Science
Department
Microbiology & Immunology
First Advisor
Swati P. Deb
Abstract
Mutations of the tumor suppressor gene, TP53, are the most prevalent oncogenic mutations in lung cancer, occurring in up to 70% of human non-small cell lung cancer (NSCLC). The majority of mutations in p53 are missense mutations that cause not only a loss of tumor suppressor function, but also gain of oncogenic functions, like tumorigenicity, immune suppression, and chemoresistance. Previous studies have shown that the depletion of gain-of-function (GOF) p53 or disruption of its ability to transactivate the expression of genes related to oncogenesis eliminates its tumorigenic properties indicating a dependency of human lung cancer cells expressing GOF p53 to execute its tumor formation ability. Thus, we hypothesized that targeting GOF p53 and its ability to transactivate gene expression could serve as a promising therapeutic target in lung cancer. Previously our laboratory developed a novel detection system to identify compounds that inhibit GOF p53-induced transactivation. In this study, we performed colony formation assays and xenograft tumor assays to evaluate one of the most promising compounds, 2-Amino-N-[[4-(5-bromopyrimidin-2-yl)oxy-3-chlorophenyl]carbomoyl] benzamide (referred to hereafter as Benzamide G3), for its ability to inhibit GOF p53-mediated transactivation. Through single-cell RNA sequencing analysis of orthotopic tumors generated in an immunocompromised mouse model, we found that treatment with Benzamide G3 resulted in differential expression of genes related to tumor-immune crosstalk in lung cancer cells containing GOF p53. Additionally, we found that treatment of lung cancer tumors harboring GOF p53 with Benzamide G3 resulted in a different tumor immune microenvironment when compared to vehicle-treated orthotopic tumors. This suggests a potential mechanism in which GOF p53-specific transactivation regulates epithelial-mesenchymal transition (EMT), by downregulating CDH1, and tumor-immune crosstalk by downregulating the expression of cytokines related to the recruitment and differentiation of macrophages, such as TNFSF15, CSF2, and GDF15. Using Benzamide G3 to specifically inhibit GOF p53-induced transcription may be useful in the development of lung cancer therapeutics.
Rights
© Brandon G. Velasco
Is Part Of
VCU University Archives
Is Part Of
VCU Theses and Dissertations
Date of Submission
5-7-2025