Doctor of Philosophy, The Ohio State University, 2023, Biomedical Engineering

Cancer metastasis is a complex, systemic, and non-random process requiring tumor cells to both adapt to and manipulate a multitude of microenvironments. Given this complexity, traditional 2D cell culture models offer insufficient structural and biological relevance, while animal models face obstacles in real-time analysis, experimental control, and translational success. As an alternative to address these barriers, this dissertation discusses development of tissue engineered microfluidic device-based tumor-on-a-chip platforms to isolate phases of metastatic colonization and study premetastatic microenvironmental changes. In this dissertation, this hydrogel-based technology was applied in three different aspects of metastatic progression. First, a thyroid metastasis-on-a-chip model was developed to study metastasis suppressor gene RCAN1-4 and its impact on downstream lung colonization. Second, 3D hydrogel scaffolds were implemented to investigate colorectal cancer-induced collagen remodeling by stromal fibroblasts and pericytes during premetastatic niche development. Third, observations of cancer-induced collagen remodeling were used to inform design of a liver premetastatic niche-on-a-chip model to further interrogate immune-myofibroblast crosstalk in response to colorectal cancer signaling and establish the relationship between this crosstalk and metastatic colonization.

Committee: Aleksander Skardal (Advisor); Daniel Gallego-Perez (Committee Member); Jennifer Leight (Committee Member); Jonathan Song (Committee Member) Subjects: Biomedical Engineering; Biomedical Research; Oncology

Doctor of Philosophy, The Ohio State University, 2022, Molecular Genetics

StARkin domains are a superfamily of structurally conserved ligand binding domains found in all the domains of life. These domains use a diverse set of mechanisms to regulate the activity of multidomain proteins they are integrated into, will identified roles in mediating homo/heteromeric interactions, subcellular localization, protein stability, and protein turnover. One subfamily of StARkin domains, StAR-related lipid transfer (START) domains, is found in both plant CLASS III HOMEODOMAIN-LEUCINE ZIPPER (HD-ZIPIII) transcription factors (TFs) and human deleted in liver cancer (DLC) tumor suppressor genes. Both families of proteins have critical roles in development, however, roles of the START domain in regulating the activity of either of these protein families is largely unknown. In Arabidopsis thaliana, phylogenetic analysis of HD-ZIPIII paralogs shows divergent activity stemming from coding sequence divergence, separating the five HD-ZIPIII paralogs into two sister clades, the REVOLUTA clade and the CORONA clade. HD-ZIPIII paralogs have redundant developmental activities, with distinct and antagonist effects between these sister clades. Preliminary work in our lab investigating the START domain of a representative REVOLUTA clade paralog, PHABULOSA (PHB), shows that the START domain is required for the developmental activity of PHB and regulates homodimerization, DNA-binding, and transactivation potential. In this study, I present the divergent activity of a representative CORONA clade paralog, CORONA (CNA), mediated by its START domain. We identify the target genes of PHB and CNA, highlighting overlapping, distinct, and antagonist regulation of target genes representative of their redundant developmental roles with distinct, and antagonist effects on each other. Additionally, using domain swap experiments, I identify two new properties of the CNA START domain in modulating the behavior of the binding sites of CNA, as well as modulating transactivation / tra (open full item for complete abstract)

Committee: Aman Husbands (Advisor); Jay Hollick (Committee Member); Mark Seeger (Committee Member); Ruben Petreaca (Committee Member); Amanda Bird (Committee Member) Subjects: Biology; Molecular Biology; Plant Biology

Doctor of Philosophy, The Ohio State University, 2021, Chemical Physics

Cancer is a disease that affects millions of people each year, and cancer detection is currently done using costly and inefficient methods. The purpose of this research has been to develop methods that use infrared spectroscopy and machine learning to accurately and efficiently detect cancer. The vibrational information from the molecules of tissue can be accessed through infrared spectroscopy and various spectral metrics including those from spectral peak ratios, calibrant spectra, and principal component analysis of spectral libraries. This information is coupled with machine learning methods for separation and feature selection. Using these methods, two imaging experiments were conducted on SKH-1 mice with skin cancer and colorectal cancer metastatic to the liver in humans. Support vector machine learning methods were able to separate the tumor spectra from other spectra, including nontumor, with high accuracy. Support vector machines were also used to determine optimum peak ratios for separation to reduce the number of wavelengths needed. Support vector machine methods were also compared with metrics from currently used tissue staining techniques – hematoxylin and eosin – which showed that infrared spectra are more effective at separating cancer under the present conditions. These known optical techniques were also joined with infrared spectroscopy for a combined approach. Using the support vector machine decision equation, images of tissue were created to aid in the diagnosis of cancer. The methods developed were used as a basis for the design of a fast infrared probe that can detect skin cancer with high levels of accuracy in a clinical trial. The fast infrared probe was also able to separate between two different types of skin cancer – basal and squamous cell carcinomas. This prototype probe could be modified with an etalon filter to increase the efficiency of the probe when used in a clinical setting. This research develops and tests methods that show that i (open full item for complete abstract)

Committee: James Coe Ph.D. (Advisor); Heather Allen Ph.D. (Committee Member); Sherwin Singer Ph.D. (Committee Member); Dongping Zhong Ph.D. (Committee Member) Subjects: Chemistry; Physics

Doctor of Philosophy, Case Western Reserve University, 2013, Pathology

Advancement of stem cell biology is critically dependent on improved isolation and characterization of stem cells. This thesis describes a) the development of two novel screening assays for stem cells and b) characterizes the expression of the stem cell marker Lgr5 in two anatomically distinct tissue compartments. Whole-animal lineage tracing provides global in situ expression analysis, which can be used to evaluate stem cell proliferation, trophism, niche structures, and anatomical spatial relationships. This method accelerated the detection of Lgr5 in multiple tissues, including the liver and central nervous system. These expression patterns are impactful for regenerative medicine efforts aimed at isolating stem/progenitor cells. In addition, the data contained herein refine the understanding of the Wnt pathway in stem and non-stem cells as they exist within signaling gradients and different physiological states. Multiplex high-throughput flow cytometry is another technique that can be used to rapidly identify comprehensive surface antigen signatures of normal and cancer cells. The methodology developed in this thesis doubles potential coverage of immunophenotypes using reagents directly translatable into clinical application for enhancing cellular detection and development of targeted therapies. Since stem cells relate to the biology of homeostasis, regeneration, and cancer, the works completed in this thesis advance our medical knowledge and capabilities.

Committee: Jeremy Rich MD (Advisor); Alan Levine PhD (Committee Chair); Anita Hjelmeland PhD (Committee Member); Alex Huang MD, PhD (Committee Member); Sanford Markowitz MD, PhD (Committee Member); Clive Hamlin PhD (Committee Member) Subjects: Biology; Biomedical Research; Cellular Biology; Pathology

PhD, University of Cincinnati, 2018, Engineering and Applied Science: Biomedical Engineering

Liver cancer, including hepatocellular carcinoma and colorectal metastases, is the second greatest cause of cancer-related death worldwide. Liver transplantation is considered the gold standard for hepatic cancer treatment. However, it is limited by the availability of liver donors and by cost. Hepatic resection is another treatment option that offers a high long-term survival rate. However, the overall resectability rate is low due to chronic liver disease and tumor location. Thermal ablation, including radiofrequency ablation as well as microwave and ultrasound ablation, has become an important alternative to liver resection and transplantation. To avoid incomplete treatments and cancer recurrence while reducing morbidity, a real-time monitoring and control approach, capable of providing consistent thermal ablation in minimal time, is needed. Echo decorrelation imaging has been successfully employed to monitor ultrasound ablation and radiofrequency ablation both ex vivo and in vivo. In this dissertation, its utility for real-time control of ultrasound ablation was assessed in ex vivo bovine liver and in vivo rabbit liver with VX2 tumor. Ultrasound exposures and echo decorrelation imaging were performed using 5 MHz linear image-ablate array. Sonications were automatically ceased when the minimum or average cumulative echo decorrelation within a control region of interest (ROI) exceeded a predetermined threshold, corresponding to high specificity for prediction of local tissue ablation or complete ROI ablation. Ablation outcomes, treatment time and prediction performance were statistically compared between controlled and uncontrolled groups. For controlling ex vivo focused ultrasound treatments, a small control ROI was placed at the focal zone and the selected control threshold corresponded to 90% specificity of local ablation prediction for preliminary ex vivo experiments. Controlled trials were compared to uncontrolled trials employing 2, 5 or 9 therapy cyc (open full item for complete abstract)

Committee: T. Douglas Mast Ph.D. (Committee Chair); Syed Ahmad (Committee Member); Jing-Huei Lee Ph.D. (Committee Member); Marepalli Rao Ph.D. (Committee Member) Subjects: Biomedical Research

Master of Sciences (Engineering), Case Western Reserve University, 2017, Biomedical Engineering

Patient-derived xenografts (PDX) are living ex situ tumor models that aid clinicians in selecting potent therapies for cancer patients. Unfortunately, a liver PDX is difficult to develop due to poor liver tumor engraftment in mice hosts. Tissue engineering studies have suggested that beneficial factors may exist in extracellular matrix (ECM) that can enhance tumor viability after transplant. We conducted comparative analysis of three published decellularization protocols for efficient cell removal. ECM samples produced by Freeze-thaw with Triton X-100 (TX-100), Sodium Dodecyl Sulfate (SDS) with TX-100, and TX-100 alone, were analyzed with nuclear labeling and structural analysis. SDS with TX- 100 was efficient and caused minimal alterations to the matrix structure. Additionally, we demonstrated with developed assays that liver cell lines can respond to isolated decellularized matrix and mimic in vivo liver activity. The work completed provides confidence to study the effects of decellularized liver matrix on patient-derived liver tumors.

Committee: Samuel Senyo PhD (Advisor); Eben Alsberg PhD (Committee Member); Analisa DiFeo PhD (Committee Member); Anirban Sen Gupta PhD (Committee Member) Subjects: Biomedical Engineering

Doctor of Philosophy, Case Western Reserve University, 2017, Molecular Medicine

The era of genomic revolution illustrated that cancer is a genetic disease where alterations impair specific cellular pathways. For instance, cancer cells frequently physically remove cell death genes (i.e., TP53, CDKN2A) to impair apoptotic pathways. However, most systemic treatments of cancer are typically designed to engage cell cycle exit by apoptosis. This approach selects for apoptosis-resistant cancer cells and is toxic to normal cells. There is clear need for p53 independent non-apoptosis therapies in cancer. To proliferate, cells must execute a complex duplication and separation of entire cells: a process coordinated by the transcription factor MYC, whose growth and division function is conserved throughout metazoan evolution. Multicellular organisms are unique however, by potently antagonizing MYC function by genetic methods. This allows differentiation into layers of cells, tissues, organs and organ systems each with specialized biological function. The evolutionary process of specialization is uniquely regulated, and arises from stem cells that acquire tissue/lineage specification signals, attaining exponential outgrowth, while systemically differentiating into various tissue precursors. Differentiation, therefore routinely restrains the exponential growth of committed tissue precursors through potent physiologic antagonization of MYC and MYC related programs. The aberrant growth and division illustrates that differentiation derangement is emblematic of cancer. Hepatocellular carcinoma (HCC) - including that histologically classified as `well-differentiated' by light microscopy - displays lower expression of hundreds of specialized liver differentiation genes compared to non-malignant liver. Suppression of so many differentiation genes suggests disruption to the upstream core master transcription factor circuit that coordinates physiologic programs to terminate MYC function. We demonstrate how deletion/mutation of GATA4 - a master transcription factor (open full item for complete abstract)

Committee: Saunthararajah Yogen MD (Advisor); Scacheri Peter PhD (Committee Chair); Ting Angela PhD (Committee Member); Li Xiaoxia PhD (Committee Member); Khorana Alok MD (Committee Member) Subjects: Biochemistry; Genetics; Medicine; Molecular Biology

Doctor of Philosophy, The Ohio State University, 1981, Graduate School

Committee: Not Provided (Other) Subjects: Health Sciences

Master of Science, The Ohio State University, 2016, Biomedical Sciences

Sorafenib therapy has been shown to have only a small clinical benefit for liver cancer patients. There is an urgent needed to develop new therapeutic strategies for the treatment of advanced stage HCC. In this report, we screened several repurposed therapeutics in order to identify synergistic drug combinations. We demonstrate that the combination of 2-deoxy-glucose and sorafenib drastically inhibit HCC cell viability in Hep3B, Huh7 and sorafenib resistant Huh7 cells. Cell cycle analysis revealed that this therapeutic combination induced complete G0/G1 arrested HCC cells. Our studies suggest that this cell-cycle arrest is due to the depletion of cellular ATP. Overall, this report provides strong evidence for the clinical potential of sorafenib + 2-deoxyglucose combination therapy.

Committee: Samson Jacob PhD (Advisor); Kalpana Ghoshal PhD (Committee Member) Subjects: Medicine; Molecular Biology; Therapy

Doctor of Philosophy, The Ohio State University, 2014, Mechanical Engineering

Cancer remains a substantial health burden in the United States. Traditional treatments for solid malignancies may include chemotherapy, radiation therapy, targeted therapies, or surgical resection. Improved surgical outcomes coincide with increased information regarding the tumor extent in the operating room. Furthermore, pathological examination and diagnosis is bettered when the pathologist has additional information about lesion locations on the large resected specimens from which they take a small sample for microscopic evaluation. Likewise, cancer metastasis is a leading cause of cancer death. Fully understanding why a particular tumor becomes metastatic as well as the mechanisms of cell migration are critical to both preventing metastasis and treating it. This dissertation utilizes the complex interactions of induced electric fields with tissues and cells to meet two complementary research goals. First, eddy currents are induced in tissues using a coaxial eddy current probe (8mm diameter) in order to distinguish tumor tissue from surrounding normal tissue to address the needs of surgeons performing curative cancer resections. Measurements on animal tissue phantoms characterize the eddy current measurement finding that the effective probing area corresponds to about twice the diameter of the probe and that the specimen temperature must be constant for reliable measurements. Measurements on ten fresh tissue specimens from human patients undergoing surgical resection for liver metastases from colorectal cancer showed that the eddy current measurement technique can be used to differentiate tumors from surrounding liver tissue in a non-destructive, non-invasive manner. Furthermore, the differentiation between the tumor and normal tissues required no use of contrast agents. Statistically significant differences between eddy current measurements in three tissue categories, tumor, normal, and interface, were found across patients using a Tukey's pairwis (open full item for complete abstract)

Committee: Vish Subramaniam (Advisor); Shaurya Prakash (Advisor); Carlos Castro (Committee Member); Charles Hitchcock (Committee Member) Subjects: Biomedical Engineering; Biomedical Research; Electromagnetics; Engineering; Experiments; Mechanical Engineering; Medical Imaging

PhD, University of Cincinnati, 2002, Medicine : Molecular Genetics, Biochemistry and Microbiology

Chronic infection with Hepatitis B Virus (HBV) is a predominant risk factor associated with development of hepatocellular carcinoma (HCC). Individuals who are chronically infected with HBV are over 200-times more likely to develop HCC than those who are not infected. Multiple studies have implicated the virally encoded X protein (HBx) as the candidate oncoprotein responsible for cellular transformation. HBx forms a complex with cellular p53 tumor suppressor protein to result in modification of p53-mediated gene regulation, DNA damage detection and modulation of apoptosis. The developmentally silenced a-fetoprotein (AFP) tumor marker gene, which is transcriptionally repressed by p53, is tightly correlated with HCC development: it is reactivated in over 80% of all liver carcinomas. p53 mediates transcriptional repression of AFP through an over-lapping HNF-3/Smad4/p53 binding element located within the developmental repressor domain of the AFP promoter. Here, using AFP as a model gene, we have examined the mechanism by which p53 facilitates transcriptional repression, and how this repression is disrupted upon p53-HBx interaction. In vitro chromatin assembled transcription analysis and enzyme accessibility studies demonstrate that p53 association at the overlapping binding element is required during chromatin assembly for reorganization of AFP promoter chromatin structure to result in occlusion of restriction enzymes and general transcription factors from the transcription start site. Protein-DNA binding assays show that p53 association at this element is required to recruit mSin3A co-repressor and stabilize association of a putative Smad4 and SnoN containing co-repressor complex with AFP chromatin templates. HBx-mediated reactivation of AFP is achieved through direct p53-HBx interaction resulting in disruption of SnoN co-repressor binding to AFP chromatin templates.

Committee: Dr. Michelle Craig Barton (Advisor) Subjects:

Doctor of Philosophy, The Ohio State University, 2012, Molecular, Cellular and Developmental Biology

miR-122, the most abundant liver-specific microRNA (miRNA), is involved in many different biological functions, including cholesterol metabolism, hepatitis C virus replication, and hepatocarcinogenesis. Previous studies have shown that downregulation of miR-122 in hepatocellular carcinoma (HCC) correlates with metastasis and poor prognosis. Among the deregulated miRNAs in HCC, miR-122 is drastically reduced in HCC. Based on these observations, our hypothesis is that miR-122 is a liver-specific tumor suppressor and its loss may promote hepatocarcinogenesis. To test this hypothesis, we generated germ-line (KO) and liver-specific (LKO) miR-122 knockout mice. Both KO and LKO mice exhibited hepatic microsteatosis and hepatic inflammation at early adult stage. Lipid analysis showed accumulated hepatic triglyceride, which correlated with increased de novo triglyceride synthesis and reduced triglyceride secretion. By 6 month both KO and LKO mice develop hepatic steatosis, inflammation, and fibrosis. After twelve months, these mice produce spontaneous liver tumors resembling HCC. The HCC incidences were ~30% and ~50% in LKO and KO mice, respectively. Microarray and realtime RT-PCR analysis attributed these pathological phenotypes to dysregulated expression of signaling pathways involved in triglyceride synthesis, cytokine expression, and oncogenesis. Among the deregulated genes, Agpat1, Cidec and Mapre1 were identified for the first time as the direct targets of miR-122. Exploration of the mechanism leading to hepatic inflammation in KO and LKO mice led to the identification of CD11bhighGr-1+ subtype of inflammatory cells increased in the liver of KO mice. These cells were determined as the major source of high levels of IL-6 and TNF-α that accumulated in the livers of KO and LKO mice. Ccl2, a reported myeloid chemo-attractant, was induced in hepatocytes of KO and LKO mice and was inversely regulated by miR-122 in vitro. To establish further the tumor suppressor role of mi (open full item for complete abstract)

Committee: Samson Jacob (Advisor); Kalpana Ghoshal (Advisor); Thomas Schmittgen (Committee Member); Robert Lee (Committee Member); David Symer (Committee Member) Subjects: Biology; Biomedical Engineering; Biomedical Research; Oncology

Doctor of Philosophy, The Ohio State University, 2011, Integrated Biomedical Science Graduate Program

The endocycle is a developmentally programmed variant cell cycle consisting of successive S (DNA synthesis) and G (Gap) phases without an intervening M phase or cytokinesis. As a consequence of the regulated “decoupling” of DNA replication and mitosis, which are two central processes of the traditional cell division program, endocycling cells acquire highly polyploid genomes after having undergone multiple rounds of whole genome reduplication. Although essential for metazoan development, relatively little is known about the regulation of endocycle or its physiologic role in higher vertebrates such as the mammal. A substantial body of work in the model organism Drosophila melanogaster has demonstrated an important function for dE2Fs in the control of endocycle. Genetic studies showed that both endocycle initiation and progression is severely disrupted by altering the expression of the fly E2F activator (dE2F1) or repressor (dE2F2). In mammals, the E2F family is comprised of nine structurally related proteins, encoded by eight distinct genes, that can be classified into transcriptional activators (E2f1, E2f2, E2f3a and E2f3b) or repressors (E2f4, E2f5, E2f6, E2f7 and E2f8). The repressor subclass may then be further divided into canonical (E2f4, E2f5 and E2f6) or atypical E2fs (E2f7 and E2f8). Until this study, there has been sparse knowledge regarding the role of E2fs in the control of mammalian endocycle, or what the physiologic consequences might be of perturbed endocycles in tissues composed of polyploid cells such as the liver. Now using a combination of novel and established lineage-specific cre mice we identified that two opposing arms of the E2F program, one driven by canonical transcription activation (E2F1, E2F2 and E2F3) and the other by atypical repression (E2F7 and E2F8), converge on the regulation endocycles in vivo. Ablation of canonical activators in the two endocycling tissues of mammals, trophoblast giant cells (TGCs) in the placenta and hepatocytes (open full item for complete abstract)

Committee: Gustavo Leone PhD (Advisor); Michael Ostrowski PhD (Committee Member); Clay Marsh MD (Committee Member); Tsonwin Hai PhD (Committee Member); Kathryn Wikenheiser-Brokamp MD PhD (Committee Member) Subjects: Cellular Biology; Developmental Biology; Genetics; Molecular Biology

Doctor of Philosophy, The Ohio State University, 2010, Chemical Engineering

Oligonucleotides (ONs), including antisense oligodeoxynucleotides (AS-ODN) and small interfering RNA (siRNA) that can specifically down-modulate disease-causing gene, hold great promises in cancer and leukemia therapies. Clinical application of ONs based therapy is seriously hampered, primarily due to be lack of safe and efficient delivery systems. Lipid based nanoparticles (LNPs) have been recognized as one of the most promising delivery systems for ON therapeutics. However, LNP based ON therapeutics are not clinically available and merely a few in clinical trials. It still remains a critical challenge to design, synthesize and evaluate LNP for in vivo applications. To successfully translate the LNP technology into clinical practice, it requires collaborative efforts between engineers, pharmaceutical scientists and clinical researchers. The aim of this PhD thesis was to design, synthesize and optimize LNPs towards the clinical application of ONs using an interdisciplinary strategy. A variety of chemical and engineering approaches were developed in construction and delivery of ON loaded LNPs. Liver cancer and chronic lymphocytic leukemia (CLL) were selected as two clinical models. In Chapter 2, several new methods to enhance encapsulation and nanostructure control of ONs in LNP were designed and constructed from viewpoints of engineering and pharmaceutics. The incorporation of condensing agents such as protamine during the ethanol dilution was applied to prepare ON lipoplexes. The resultant particles still remained the onion-like structures. By adapting a novel two-step strategy to prepare pH-sensitive ON lipoplexes, the cryo-TEM imaging revealed a rich population of core-shell like nanostructures. Furthermore, cholesterol modified ONs (chol-ONs) with assistance of calcium ion were used to prepare LNPs. Clear core-shell nanostructures were observed in the LNPs containing chol-ON/calcium. To further control uniform size distribution, an engineering microfluidic app (open full item for complete abstract)

Committee: Li Lee (Advisor); Robert Lee (Committee Member); Byrd John (Committee Member); Muthusamy Natarajan (Committee Member) Subjects: Chemical Engineering

Doctor of Philosophy, Case Western Reserve University, 2012, Nursing

Primary liver cancer is the most common type of solid tumors affecting young to middle-aged individuals and the second leading cause of death in Korea. However, very little research has been conducted concerning the specific factors which contribute to quality of life in primary liver cancer patients. Considering Korea's sharply increasing incidence/mortality rates due to the disease, the issue of quality of life is expected to become more critical. This study employs a theoretical framework based on Fitzpatrick's Life Perspective Rhythm Model. The research design employs mixed methodology both quantitative data (a cross-sectional design) and qualitative data (a phenomenological approach). The purpose of this study is to explore the relationships among depressive symptoms, spiritual well-being, and quality of life as well as to examine the lived experiences of primary liver cancer patients in Korea. A total of 96 patients were consecutively recruited for quantitative data collection and 40 of these patients completed in-depth interviews. To investigate participants' demographic characteristics, a researcher-designed questionnaire was used. To measure the study variables, the CES-D Scale (Radloff, 1977) for depressive symptoms, the Spiritual Well-Being Scale (Paloutzian & Ellison, 1982) for spiritual well-being, and the SF-12v2 (Ware et al., 1996) for QOL were used. The instruments reported high reliabilities in this study: the CES-D (Cronbach's α=.80), the SWBS (Cronbach's α=.89), and the SF-12v2 (Cronbach's α=.89). In summary, there were significant negative correlations: between depressive symptoms and spiritual well-being; between depressive symptoms and QOL-PCS; between depressive symptoms and QOL-MCS. There were significant positive correlations: between spiritual well-being and QOL-PCS; between spiritual well-being and QOL-MCS. In order to predict QOL-PCS in the regression equation, spiritual well-being was the strongest predictor when controlling durati (open full item for complete abstract)

Committee: Joyce Fitzpatrick PhD (Committee Chair); Mary QuinnGriffin PhD (Committee Member); Elizabeth Madigan PhD (Committee Member); Smitha Krishnamurthi MD (Committee Member); Haeok Lee PhD (Committee Member) Subjects: Health; Health Care; Health Sciences; Nursing; Oncology

Doctor of Philosophy, Case Western Reserve University, 2009, Biomedical Engineering

Hepatocellular carcinoma (HCC) is a deadly cancer. The poor survival rate is a consequence of the absence of efficient chemotherapeutic agents and the fact that this cancer is often asymptomatic until advanced stages. In this work, the woodchuck model of HCC was used to investigate the metabolism of [(methyl)1-11C]acetate (Act). This positron emission tomography (PET) radiotracer has shown promises for detecting HCC in humans, but its metabolism is currently unknown. PET studies with 2-deoxy-2[18F]fluoro-D-glucose (FDG) first showed FDG uptake in four moderately- to poorly-differentiated tumors, which had decreased glucose-6-phosphatase to hexokinase activity ratio compared to peritumoral liver tissues. Act and [(N-methyl)11C]choline (CCho) were shown to be more sensitive than FDG for detecting HCC. Pharmacokinetic modeling showed that a two-tissue compartmental model with four rate-constants better describes the Act metabolism in HCCs with high Act uptake. A two-tissue compartmental model with three rate-constants was sufficient to describe Act metabolism in peritumoral liver tissues or in HCCs with low Act uptake. The local hepatic metabolic rate of Act utilization (LHMRAct) could quantitatively distinguish between peritumoral liver tissues or HCCs with low Act uptake and HCCs with high Act uptake. Peritumoral liver tissues and HCCs with low Act uptake were associated with high venous clearance and decreased transport of radioactive species into the second tissue compartment. The opposite was seen in HCCs with high Act uptake. In vivo studies with 14C-Act showed that high Act uptake was associated with increased incorporation of the 14C label into lipids, with phosphatidylcholine being the main metabolite. In vitro experiments showed that radiolabeled acetate was preferentially converted to radioactive carbon dioxide (CO2) or retained in water-soluble compounds in hepatocytes whereas WCH-17 cells, which are derived from an adult woodchuck hepatoma, predominantly i (open full item for complete abstract)

Committee: David Wilson L (Committee Chair); Zhenghong Lee (Advisor); Gerald Saidel M (Committee Member); Stephen Previs (Committee Member) Subjects: Oncology

Doctor of Philosophy, Case Western Reserve University, 2007, Biomedical Engineering

Cancer is the second leading cause of death in the United States, behind only heart disease. Many cancers, particularly solid tumors, are inaccessible to surgery, and current systemic chemotherapy regimens are extremely limited. As a result, developing new treatments for unresectable tumors that minimize side effects is an active area of research. For example, image-guided radiofrequency (RF) ablation has had considerable success for treatment of liver tumors, but tumor recurrence at the periphery of the original tumor site is common. Recent work has proposed improving the efficacy of RF ablation by delivering a drug to the treatment area with a chemotherapeutic, biodegradable implant made of poly(D,L-lactide-co-glycolide) (PLGA). Previous studies have shown that these implants can successfully deliver antineoplastic drugs to normal and ablated liver in animal models. To establish the efficacy of these implants in treating tumors, drug-releasing PLGA implants were manufactured and tested in a rabbit liver tumor model both with and without radiofrequency ablation. Information gathered from the tumor drug distributions was used to develop a computer simulation for comparing alternative tumor treatment configurations. Optimal combined treatments were developed using the simulation and further validated with an animal model. The result of these studies is a comprehensive strategy for treating unresectable tumors with drug-containing implants and RF ablation that may ultimately impact treatment of unresectable tumors in humans.

Committee: Agata Exner (Advisor) Subjects: Engineering, Biomedical

Master of Science, The Ohio State University, 2013, Pathology

Hepatocellular carcinoma (HCC) is the third most common cause of cancer-related death worldwide. There are a limited number of therapeutic options currently available to delay the advancement of HCC, and the chance of survival decreases as the disease progresses. DNA methylation of certain tumor suppressor genes and hypomethylation of oncogenes have been shown to initiate HCC. 5-hydroxymethylcytosine (5-hmC), recently identified sixth base of the genome, can cause demethylation by its conversion to cytosine through reactions catalyzed by the TET enzymes. Research on the role of this novel modification in the liver and HCC is needed before it can be therapeutically targeted. To this end, we planned to perform systematic analysis of the role of 5-hmC in liver biology and its aberrations in HCC. In the present study, DNA from primary human HCC and matching benign livers were used to compare alterations in 5-hmC level, if any, in tumors. Mouse models of HCC were also used to further validate the results obtained from human specimens. We observed remarkable decrease in global 5-hmC content in HCCs of both human and rodent origin using multiple techniques that include dot blot, immunohistochemistry, and LC/MS analysis. Furthermore, specific regions of EGFR, H19, and 7SL loci also exhibited reduced 5-hmC levels in the tumor samples. Since aberrations in methylation can cause cancer including HCC, it would be important to identify differentially hydroxymethylated genes in the liver and the consequence of their differential hydroxymethylation in HCC.

Committee: Kalpana Ghoshal (Advisor); Samson Jacob (Committee Member) Subjects: Biology; Genetics; Molecular Biology; Oncology