Matching Items (3)
Description
Esophageal adenocarcinoma (EAC) is one of the most lethal and fastest growing cancers in the United States. Its onset is commonly triggered by metaplastic transformation of normal squamous esophageal epithelial cells to Barrett's esophagus (BE) cells in response to acid reflux. BE patients are believed to progress through non-dysplastic metaplasia and increasing grades of dysplasia prior to EAC. Conventional cancer diagnostic tools rely on bulk-cell analyses that are incapable of identifying intratumoral heterogeneity or rare driver cells that play important roles in cancer progression. An improved single-cell method of cancer diagnosis would overcome this challenge by detecting cancer initiating cells before they progress into untreatable stages. In this study, using EAC as a model, we attempted to identify a more effective method of cancer diagnosis. We quantified the single- and bulk-cell mRNA expression of genes that have been proposed to be instrumental in the progression of EAC through BE. Quantitative Reverse Transcription Polymerase Chain Reaction (qRT-PCR) analysis was performed on human primary cells to measure the mRNA expression levels of BE- and EAC-associated genes. Our results showed high levels of heterogeneity of CDX2 and TFF3 at the single-cell resolution in human BE and EAC samples. Additionally, while expression of VEGF is generally low at the bulk-cell level, our results showed that a few, rare cells had significantly higher VEGF expression levels than the majority of cells in the EAC sample. In conclusion, we have affirmed that EAC cancer cells, as well as BE cells, show high levels of heterogeneity. Based on the VEGF gene expression pattern, single-cell analysis could potentially be more effective for identifying rare, but essential cells for cancer progression, which could then be targeted for treatment. Future studies will focus on analyzing human samples from thousands of normal and cancer subjects to validate the use of single-cell profiling in cancer.
ContributorsHaeuser, Kelsey Lynn (Author) / Tran, Thai (Thesis director) / Kelbauskas, Laimonas (Committee member) / Gao, Weimin (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2013-12
Description
Esophageal adenocarcinoma is one of the largest growing cancer types in the United States and the whole world. One of the only known precursors to EAC is Barrett’s Esophagus, the changing of the normal squamous cells which line the esophagus into intestinal cells, following repeated exposure to gastric acids via gastroesophageal reflux disease. There is limited knowledge of the mutations and drivers that contribute to EAC’s low 5-year survival rates, demonstrating a need to identify new therapeutic targets. Given the development of EAC from chronic inflammation and acidic microenvironment, elevated expression of tumor necrosis factor receptor super family member 12A (TNFRSF12A, FN14) and its corresponding ligand, TWEAK, is correlated with disease progression. The functional role of the TWEAK/FN14 signaling axis is well documented in other cancer types, contributing to tumor invasion, migration, and survival. However, reports have shown the TWEAK/FN14 signaling axis can contribute “pro-cancer” and “anti-cancer” phenotypes in different tumor microenvironments. In this study, we seek to demonstrate the functional role of TWEAK and FN14 in EAC survival and migration. We hypothesized TWEAK/FN14 signaling would promoted EAC cell survival and migration. In this study, we illustrate increased expression of FN14 with disease progression. Following treatment with TWEAK, human EAC cell lines had increased sensitivity to standard chemotherapy treatment in vitro. Treatment with TWEAK also correlated with increased cellular migration, most likely in correlation with NF-κB activation. Finally, we showed that inhibition of FN14 via siRNA significantly reduced EAC survival and increased efficacy of standard of care treatments. This data suggests a diverse functional role of the TWEAK/FN14 signaling axis in EAC, and may be a potential target for novel therapeutics.
ContributorsFornefeld, Lucas Christien (Author) / Stout, Valerie (Thesis director) / Whitsett, Timothy (Committee member) / Carson, Vashti (Committee member) / School of Life Sciences (Contributor) / W. P. Carey School of Business (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
Prevalence of esophageal adenocarcinoma (EAC) has increased six-fold in the United States over the past four decades due to increases in associated risk factors, namely obesity and gastroesophageal reflux disease. The most common genomic driver of EAC, tumor protein 53 (TP53) mutation, has previously been therapeutically intractable, affirming the unmet clinical need to deploy novel therapeutic strategies targeting this genomic driver in this tumor type. 72 percent of EAC patients have mutations in TP53, making tumors more reliant on the G2/M checkpoint to repair DNA damage, increasing likelihood of efficacious G2/M abrogation via targeting WEE1 G2 checkpoint kinase (WEE1), a modulator of this checkpoint. We hypothesize that the G2/M checkpoint represents a viable therapeutic avenue against the most common genomic driver of EAC. We investigated the efficacy of the WEE1 inhibitor AZD1775 on EAC cells. WEE1 mRNA expression levels in EAC are elevated compared to normal tissue controls. AZD1775 was shown to induce cyclin dependent kinase 1 (CDK1) mediated cell cycle progression and increased DNA damage markers as exposure increased via immunoblot analysis. SK-GT- 4 EAC cell line viability was significantly reduced by up to 30 percent when treated with AZD1775 and cisplatin when compared to cisplatin alone. AZD1775 monotherapy showed high efficacy in some EAC settings. Simultaneous dual therapy demonstrated the highest overall efficacy, and stepwise sequential treatments offered negligible benefit. Future research will explore the genomic contexts of the EAC celllines used in order to understand the different responses to AZD1775 monotherapy regimens. Ionizing radiotherapy will be employed in order to understand the DNA damage response timeline, providing more information on the mechanisms of G2/M checkpoint inhibitors in this disease setting. This research will provide insight into novel therapeutic targets for EAC leading to therapeutic testing and improved patient outcome.
ContributorsBone, Landon David (Co-author) / Carson, Vashti M. (Co-author, Committee member) / Blomquist, Mylan (Co-author) / Inge, Landon J. (Co-author) / Lake, Douglas F. (Thesis director) / Whitsett, Timothy (Committee member) / School of Molecular Sciences (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05