D. Litt et Phil. / It is well known that high levels of anxiety and/or depression often accompany the diagnosis and treatment of cancer. Literature from various sources, but in particular from the fairly new field of research, Psychoneuroimmunology, also provides ample evidence that excessive anxiety and/or depression can be immunosuppressive. It makes sense, therefore, that any intervention restoring balance to the immuno-regulatory system, thereby allowing the body’s innate healing processes to focus on eliminating cancer, is highly desirable. In line with current thinking based on the mind-body connection as well as cognitive behavioural techniques utilised in many therapeutic settings, various psychological interventions have been found to help the patient gain a better sense of control over distressing symptoms and side-effects of cancer. Some of these include: basic cognitive restructuring, hypnotherapy, relaxation-meditation techniques, art and music therapy, and guided imagery. Substantial international research illustrates the beneficial effect that relaxation and/or guided imagery provides in such diverse settings including work, sport and health. In this regard, it was decided to run a pilot study to ascertain whether a customised tape recording with a relaxation and guided imagery dialogue aimed at helping patients manage and cope with negative symptoms of cancer, could significantly reduce anxiety levels in patients with cancer receiving radiotherapy. To operationalise the above, 30 men and women, aged between 20 and 80, with Stages 1, 2 or 3 breast, prostrate, gynaecological cancers, and head and neck cancers, who were about to commence radical (minimum 25 fractions) radiotherapy, were randomly selected to an experimental and a control group. A consecutive sample, pre-test post-test experimental design was applied to this study in which the experimental and control groups were subjected to pre- and post radiotherapy Hospital Anxiety & Depression (HAD) Scale, Institute for Personality Assessment and Training (IPAT) Anxiety Scale and blood pressure measurements during their 1st, 3rd, 6th week cycle of treatments, as well as a final measurement 12 weeks after commencement of therapy. The main hypothesis of this pilot study was that there would be statistically significant decreases in levels of anxiety as a result of the intervention of guided imagery tape recording in patients with non-metastatic cancer undergoing curative radiotherapy. For the intervention, each experimental participant was taught a relaxation technique and then following an interview a customised guided imagery dialogue developed for the participant’s sole use. The participant was requested to listen to this tape at least once a day. The control group had the same pre- and post tests as the experimental group, but did not receive any intervention. Statistical analysis of the data revealed that the experimental group showed a tendency towards decreased blood pressure and anxiety over the course of radiotherapy. The most significant change, however, was noted in terms of diastolic blood pressure, suggesting that the intervention corresponded to a physiological decrease in anxiety. There was not a statistically significant difference in terms of the measured psychological variables. A general conclusion to this pilot study suggests that whilst guided imagery may contribute to a lowering of anxiety, additional cognitive intervention would probably affect a more substantial and sustained change in the patient. Although this pilot study revealed some methodological weaknesses the results are sufficiently encouraging to warrant further in-depth research regarding the use of guided imagery as a cost-effective, easy method for individuals to learn and utilise as part of their integrative cancer treatment programme.

Inflammatory Breast Cancer (IBC) is a rare, lethal, and understudied form of breast cancer. Although affecting 1-2% of the population, the remission rate is half that of the spectrum of other breast cancers, and most cases present in the advanced stages due to rapid undetectable development. Of the diagnosed cases, systemic chemotherapeutics are relatively ineffective in comparison to non-IBC breast cancer cases, indicating other unique mechanisms driving IBC progression. Historically, the specific sensitivities of a particular tumor type or subtype have been linked to genetic alterations that represent addiction hubs, such as hyperactivation of oncogenes due to mutation. Although some efforts have been made to characterize the molecular fingerprint of inflammatory breast cancers (IBCs), unfortunately, no clinical application has emerged from these studies. Thus, we decided to utilize a different strategy to identify the Achilles' heel of IBC cells. Using shRNA libraries, we performed an unbiased genome-wide loss-of-function screen comparing the gene functions required for survival of IBC and non-IBC cells. Histone deacetylase 6 (HDAC6) emerged as one of the top genes required for IBC cell survival and was further validated. HDAC6 is vital in the cell's unfolded protein response (UPR) to clear misfolded or toxic protein, and IBC cells proved to be preferentially sensitive to this aspect of HDAC6 inhibition, displaying increased protein accumulation, ER stress indicators, and subsequent apoptosis upon failure to clear or refold accumulated proteins. These data indicate HDAC6 is a crucial gene required for IBC cell line survival, in part due to its function in IBC cell UPR. Furthermore, emerging orally bioavailable agents for HDAC6 inhibition make it a promising candidate towards tailored therapeutic implementation in IBC patient trials.

Small molecules are a powerful tool to illuminate biological mechanisms and assist in the identification and validation of therapeutic targets. KRAS is the single most frequently mutated oncogene in human cancer, with particularly high mutation frequencies observed in pancreas (95%), colon (45%), and lung (35%) cancer. However, despite three decades of effort, there is no clinical viable KRAS cancer therapy. The first part of this thesis focuses on exploring the potential of directly targeting the KRAS nucleotide binding site. Directly targeting oncogenic KRAS with small molecules in the nucleotide-binding site has had limited success due to the high affinity of KRAS for nucleotide GTP and the high cellular concentration of GTP. The strategy of generating engineered KRAS allele based on shape and covalent complementarity was exploited herein to address this challenge. Using fragment-based small molecule design, a cell-membrane-permeable covalent inhibitor able to irreversibly modify the engineered nucleotide-binding site of KRAS was developed. The second part of this thesis describes the investigation of the therapeutic potential of imidazole ketone erastin (IKE), a small molecule inhibitor of the cystine/glutamate antiporter system xc–, in a subcutaneous xenograft model of Diffuse Large B Cell Lymphoma (DLBCL). A biodegradable polyethylene glycol-poly(lactic-co-glycolic acid) nanoparticle formulation was employed to aid in the delivery of IKE to cancer cells in vivo. This IKE nanoparticle system showed improved tumor accumulation and therapeutic index relative to free IKE, indicating its potential for treating DLBCL. The final part of this thesis describes the study of lipid metabolism features of ferroptotic cell death using quantitative reverse transcription PCR (RT-qPCR) and mass spectrometry-based lipidomic analysis. In summary, this work illustrates how chemistry and chemical biology approaches can supplement existing efforts towards the design and discovery of new drugs for challenging targets, as well as aid in the study of therapeutic mechanisms.

Due to the difficulty of a complex commissioning technique for a multi energetic, multi-modality linear accelerator, I perform all the commissioning and acceptance testing for a TrueBeam linear accelerator with 4 megavoltage (MV) energies of which 2 are flattening filter-free (FFF) and 6 electron energies varying from 6 MeV to 20 MeV. A 2 dimensional (2D) water tank was used for scanning all the required field sizes for all the energies. The one dimensional (1D) water tank was used to collect all the output factors for all the photon fields sizes small to medium electron field sizes. For the large electron fields sizes, we had to use the 2D water tank. All the collected data was converted into a file type accepted by the planning system (Eclipse) and subsequently imported there. Treatment plans were generated using multiple forms of planning to verify the viability and quality of the beam data commissioned. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection

published_or_final_version / Public Health / Master / Master of Public Health

published_or_final_version / Pathology / Master / Master of Philosophy

published_or_final_version / Chinese Medicine / Doctoral / Doctor of Philosophy

Hepatocellular carcinoma (HCC) is one of the most devastating malignancies worldwide with increasing incidences in both developed and developing countries. Survival rates have not been significantly improved over the past decades in spite of advances in detection and therapies for this disease, suggesting that current treatments may target the wrong cells, and miss the cancer stem cells (CSCs). The cancer stem cell hypothesis presents that tumor formation, proliferation and propagation are driven by a rare subpopulation of chemoresistant CSCs that are not killed by conventional therapies and go on to cause disease relapse. The objective of this study was to identify and characterize CSCs in HCC cell lines and human liver tumor specimens using CD90 as a potential marker. The number of CD90+ cells present in HCC cell lines was found to positively correlate with tumorigenicity potentials. Injection of as few as 2,000 sorted CD90+ cells from HCC cell lines resulted in the formation of tumor nodules in nude mice, whereas no tumors formed for CD90ˉcells in the same model. The tumor xenograft generated by injection of CD90+ cells sorted from previous xenograft in a serial xenotransplantation assay exhibited recapitulation of tumor heterogeneity to original primary tumor and consistent proportion of CD90+ and CD90ˉ cells which demonstrated self-renewal and differentiation capacities of CD90+CSCs. CD45ˉCD90+ cells were detected (0.03%–6.2%) in human liver tumor specimens, but were only present in minute quantities in normal, cirrhotic and non-tumorous tissues. More importantly, CD45ˉCD90+ cells sorted from primary HCC tumor also displayed tumorigenicity, self-renewal and lineage differentiation capacities. CD90+CSCs were found to be more resistant to therapeutic drugs compared to CD90- cells, as reflected by the results of enrichment of the CD90+ CSCs and longer survival rates after chemotherapeutic treatment. The high expression of genes, such as OCT4, MRP3, ABCG2, AKT1, BirC5, BCL2, HA and CD44, in CD90+CSCs may mediate chemoresistance. The majority of CD90+ cells co-expressed CD44, another stem cell marker. Blocking CD44 activities by anti-CD44 antibody increased apoptosis of CD90+ CSCs, sensitized CD90+CSCs to chemotherapeutic drugs in vitro, and decreased tumorigenic and metastatic potentials of CD90+CSCs in vivo, indicating that a therapeutic potential of targeting CD44. However side effects may be problematic due to the endogenous expression of CD44 in healthy tissues and normal lymphocytes. To identify novel gene targets specific to liver CSCs, a sensitive RNA-sequencing (RNA-Seq) technique was used to compare the gene expression profiles between CD90+CSCs sorted from HCC primary tumors and CD90+cells from adjacent non-tumorous tissue (CD90+NTSCs). The up-regulated genes in CD90+CSCs were associated with lipid metabolism, inflammation, and drug resistance. Among the differentially expressed genes, glypican-3 (GPC3) was specifically elevated in CD90+CSCs but not in CD90+NTSCs. Therefore, GPC3 could be a promising gene candidate for HCC therapy as targeting GPC3 should not induce damage to normal liver stem cells. In summary, CD90 is a liver CSCs marker. Identification of CD90+ CSCs in HCC provides new insight into cellular basis of hepatocarcinogenesis, recurrence and metastasis, which opens new avenues for the design of future CSC-targeted therapies. / published_or_final_version / Surgery / Doctoral / Doctor of Philosophy

Nasopharyngeal carcinoma (NPC), endemic in southern China and Southeast Asia, was ranked 7th as the most common new malignancy in Hong Kong. Metastatic and recurrent NPC have a poor prognosis despite recent advancement in medicine. Inactivation of tumor suppressor genes (TSGs) through the loss of chromosomal regions is frequently reported in NPC. With the recent discovery of cancer stem cells (CSCs), which are refractory to current therapies, a new paradigm shift in the perspective of cancer therapy development has emerged. For the first time, this study aims to unravel the complexity of NPC tumorigenicity for identifying more effective targets by studying the possible interplay between CSCs and TSGs. NPC cell lines had different expression profiles of CSC markers, confirming not all CSC markers are applicable to every tumor type. Although CD24/CD44 were expressed in NPC, however CD24+CD44+ NPC cells did not initiate tumor formation. By utilizing a cancer hybrid cell model with a transferred single copy of chromosome 3, physiological β-catenin up-regulated core stem cell markers through the activation of Wnt signaling pathway in NPC. Moreover, the down-regulation of β-catenin suppressed chemoresistance and inhibited cell proliferation, colony formation, angiogenesis, the epithelial-mesenchymal transition (EMT) process, and the tumor microenvironment factors. Amongst the tumor microenvironment factors, chemokine Rantes and matrix metalloproteinase were down-regulated when β-catenin was knocked down. Therefore, activation of Wnt signaling provide an alternative platform for identifying putative CSCs in NPC, leading to the identification of several prospective CSC markers in NPC. Down-regulation of IKBB, a NF-KB inhibitor, in the majority of NPC patients indicated that IKBB plays a prominent role as a TSG in NPC. In this study, IKBB was found to exert its tumor suppressive functions by abrogating tumor formation, cell migration, invasion and angiogenesis. Angiogenic factors, including Rantes, Upar, IL6 and IL8, were significantly down-regulated by IKBB. In addition, IKBB also suppressed the binding activity of NF-KB. The involvement of Akt/Gsk-3β pathways was also observed. Taken together, IKBB regulated NPC tumorigenesis through NF-KB/Akt/Gsk-3β and interaction with tumor microenvironment. Collectively, this study demonstrated that the progression of NPC is not simply initiated by a single signaling pathway, but a dynamic and complex interplay between multiple signaling networks and the tumor microenvironment. NPC tumorigenesis is hypothesized to be driven by orchestrated interaction between CSCs and TSGs through crosstalk with the tumor microenvironment. Amongst the major players in the tumor microenvironment, Rantes/CCL5, IL6, and the matrix metalloproteinase are envisaged to induce angiogenesis, EMT, and metastasis in NPC. This dynamic intercommunication between CSCs and tumor suppressor IKBB signaling networks may shed better insights on modulation of the major hallmarks of cancer in orchestrating NPC development. The modulation of the major hallmarks of cancer by CSCs and IKBB, a TSG, involves promotion of aberrant proliferation, enhancement of invasion and metastasis, induction of angiogenesis, circumvention of tumor suppressors, and prevention of cell death. Taken together, selective and synergistic co-targeting these signaling networks and the tumor microenvironment will provide a more effective new modality of treatments for NPC. / published_or_final_version / Clinical Oncology / Doctoral / Doctor of Philosophy

Oncogenic mutations in lung cancer further our knowledge about cancer initiation and progression, and may guide personalized treatment. The fact that targeted therapy is most effective in subsets of patients with defined molecular targets indicates the need for classification of clinically-related molecular tumor phenotypes based on the presence of oncogenic mutations, including EGFR mutations and EML4-ALK rearrangements. The identification of EGFR mutations, in up to half of lung adenocarcinomas in Asians, could predict clinical sensitivity to tyrosine kinase inhibitor (TKI). However, testing for mutations is not always possible due to tumor tissue availability. The therapeutic decision sometimes remains a clinical one especially for elderly lung cancer patients but no known mutation status. We studied the survival outcomes of targeted therapy versus conventional chemotherapy in elderly patients with lung cancer when we did not yet have routine EGFR mutation testing and demonstrated comparable survival outcomes in targeted therapy compared to chemotherapy, implying that survival with targeted therapy could be better if the treatment population could be selected with EGFR mutations. Though testing for EGFR mutation in tumor biopsy have later become routine practice and remains the accepted reference for therapeutic decision, the detection of EGFR mutations in plasma DNA with high diagnostic performance will be useful adjunct for diagnostic and therapeutic monitoring. Among patients with EGFR mutations in tumor biopsy, the concurrent detection of EGFR mutation in plasma DNA was found to confer a less favorable prognosis in terms of overall survival than those patients with EGFR mutations in tumor biopsy but the corresponding mutation was not detected in plasma. Other oncogenic mutations with therapeutic implications in lung tumors are yet to be fully explored, like ALK, KRAS, ROS1 or NTRK1 mutations. It is not exactly the tumor – but the mutations in the tumor that need to be explored with reference to clinical behavior. Even with EGFR mutation with well-established clinical implications, further exploration into its mechanistic functions will help in understanding of drug resistance. Lung cancer cell lines established from patients with known mutation profiles could be useful tools for studying the biology of known molecular targets as well as for therapeutic testing. Four new lung adenocarcinoma and one mesothelioma cell lines were established from patients with different clinical characteristics and oncogenic mutation profiles. These cell lines with defined mutation profiles will provide tools for exploration of lung cancer and mesothelioma biology with respect to molecular therapeutic targets. The Large Tumor Suppressor 2 (LATS2) gene was a differentially expressed gene between EGFR mutant and wildtype lung adenocarcinomas. The differential LATS2 expression levels were predictive of survival in patients with resected lung AD and may modulate tumor growth via different signaling pathways in EGFR mutant and wild-type tumors. The identification of oncogenic mutations has led to a new paradigm of targeted therapy in lung cancer. Further improvements in outcome of lung cancer management will stem from research into the biology of oncogenic mutations and their clinico-pathological correlations, which would fuel parallel development of clinically efficacious targeted therapies. / published_or_final_version / Medicine / Master / Doctor of Medicine