A unique tumor targeted method, which may be able to deliver a molecule to the surface of a tumor cell using the pH gradient between hypoxic tumor cells and normal tissue has recently been developed. Since solid tumors have been found to have a lower extra cellular pH compared to normal tissue (6.5 to 6.9 for tumors verses an average 7.4 for normal tissue), the pH gradient is used as a source of power to activate a strategically designed "molecular engine" capable of delivering a diagnostic or therapeutic agent to tumor cells. To test this hypothesis, a 22- sequence amino acid, which reorganizes to alpha helical form at pH 6.9 causing the molecule to become lipophilic and embed into the plasma membrane of nearby cells was synthesized. The molecule was then attached to 99mTc via a MAG-3 chelating molecule. In-vivo nuclear imaging was performed and showed apparent significant uptake in primary tumors as well as lung and liver in Lewis lung cell model C57blk-J6 mice with confirmed primary tumors at the base of the tail or lungs. This study shows significant promise for early diagnosis and treatment of cancer on a molecular level. / Graduation date: 2006

Thesis (Ph.D.) - Carleton University, 2007. / Includes bibliographical references (p. 230-245). Also available in electronic format on the Internet.

El objetivo principal de este trabajo es definir las características clínicas de los tumores de intestino delgado según su tipo. Se revisaron retrospectivamente los archivos de anatomía patológica y los archivos de historias clínicas del Hospital Edgardo Rebagliati Martins, eligiendo los casos con diagnóstico de tumores benignos y malignos del intestino delgado, correspondientes al período de enero de 2003 a marzo de 2005. De ellos se seleccionó un total de 107 casos que cumplían con los criterios de inclusión y se estudió su historial clínico para llenar la ficha de recolección de datos. De la observación de los 107 casos seleccionados surge como categoría relevante el predominio del tumor de tipo histológico maligno, siendo el más frecuente el adenocarcinoma (68,9%), seguido del linfoma (21,60%). Entre los tumores benignos el más recurrente resulta ser el pólipo del duodeno (46,15%). La edad promedio de aparición de la enfermedad fue a partir de la sexta década de vida y, en cuanto a las manifestaciones clínicas, el dolor abdominal fue el predominante en todos los tipos de tumor encontrados. Con este trabajo demostramos que la disminución de peso corporal y el dolor abdominal son manifestaciones importantes para el diagnóstico. Frente a todo paciente de 60 años o más con disminución de peso, recurrente dolor abdominal y sin otra molestia aparente debe pensarse en tumor de intestino delgado.

Thesis advisor: Gabor Marth / Unlike normal tissue cells, which contain identical copies of the same genome, tumors are composed of genetically divergent cell subpopulations, or subclones. The abilities to identify the number of subclones, their frequencies within the tumor mass, and the evolutionary relationships among them are crucial in understanding the basis of tumorigenesis, drug response, relapse, and metastasis. It is also essential information for informed, personalized therapeutic decisions. Studies have attempted to reconstruct subclone structure by identifying distinct allele frequency distribution modes at a handful of somatic single nucleotide variant loci, but this question was not adequately addressed with computational means at the start of this dissertation work, and recent efforts either enforce certain assumptions or resort to statistical procedure which cannot guarantee the complete landscape of solution space. This dissertation present a computational framework that examines somatic variation events, such as copy number changes, loss of heterozygosity, or point mutations, in order to identify the underlying subclone structure. Chapter 2 discuss the presence of intra-tumoral heterogeneity, and for historical interest, a method to reconstruct the parsimonious solution based on simplifying assumptions in tumor micro-evolution process. Analysis results on clinical datasets concerning Ovarian Serious Carcinoma and Intracranal Germ Cell Tumor based on this method, which confirmed the genomic complexity, are also presented. Due to the reason that the linkage information i.e. whether two mutations are co-localizing in the same cancer cell is lost during tissue homogenization and DNA fragmentation, common sample preparation steps used in whole genome profiling techniques, often there are more than one subclone model capable of explaining the observation. Chapter 3 describes an extended method that is able to search for all models consistent with the observation. Consequently, the solution to a specific input dataset is then a set of possible subclone structures. The method then trim this solution space in the case that more than one sample from the same patient are available, such as the primary and relapse tumor pairs. Furthermore, a statistical framework is developed that, when further trimming is not possible, predicts whether two mutations are co-localizing in the same subclone. The formal definition on the problem of subclone structure reconstruction, as well as techniques to pre-process various types of genomic variation data are given given here as well. Results on the analysis of published and novel datasets, ranging from cancer types including Acute Myeloid Leukemia, Sinonasal Undifferenciated Carcinoma and Ovarian Serious Carcinoma, and data types including whole genome sequencing, copy number array, single nucleotide polymorphism array and single nucleotide variant calls with deep sequencing are also included. They show that the method is applicable to these wide range of cancer and data types, able to independently replicate the published conclusion based on manual reasoning, and gain novel insights into the pattern of tumor recurrence and chemoresistance. It also shows that the method can be valuable in prioritizing variants for function study. / Thesis (PhD) — Boston College, 2014. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Biology.

No description available.

Gestational trophoblastic disease (GTD) encompasses a heterogeneous group of trophoblastic lesions. It includes hydatidiform mole (HM), choriocarcinoma (CCA), placental site trophoblastic tumour (PSTT) and epithelioid trophoblastic tumour (ETT). While the latter three are classical malignancies, HM represents abnormal placenta harbouring malignant potential and may develop persistent gestational trophoblastic neoplasm (GTN) requiring therapy. Apoptotic activity and p53 are known to be important in pathogenesis of GTD. However, understanding on the underlying mechanisms is still limited. ASPP1 and ASPP2 are the two tumour suppressor members of the apoptosis stimulating protein of p53 (ASPP) family that stimulate p53-dependent apoptotic pathway. In this study, a differential downregulation of ASPP1 and ASPP2 was observed in GTD, illustrating their distinct roles in the pathogenesis. Results showed that both ASPP1 mRNA and protein levels were significantly downregulated in HM and CCA, when compared with normal placentas by quantitative polymerase chain reaction (qPCR) and immunohistochemistry. Methylation-specific polymerase chain reaction (MS-PCR) in placenta and GTD samples demonstrated a significant correlation between ASPP1 mRNA level and their hypermethylation status (P = 0.024). Most importantly, lower ASPP1 immunoreactivity was found in HM that progressed into persistent GTN than HM that regressed (P = 0.045). Significant correlation was also found between expression of ASPP1 and apoptotic activity (M30 CytoDeath index), p53 and caspase-8 immunoreactivities. In CCA cell lines, namely JEG-3 and JAR, ectopic expression of ASPP1 triggered apoptosis through intrinsic and extrinsic pathways as indicated by an increase in cleaved caspase-9 and Fas ligand protein expression, demonstrating a potent tumour suppressive function through its proapoptotic nature. Downregulation of ASPP2 was mainly detected in choriocarcinoma, the most aggressive form of GTD. In vitro, results showed that ASPP2 was a multi-functional protein with activities not limited to apoptosis stimulation. While activated Src is important in tumour progression, transfection of ASPP2 but not ASPP1 was found to be related to decreased Src-pY416 phosphorylation. This suggested an inactivating effect of ASPP2 on Src. Moreover, this ASPP2-induced inactivation of Src could be abolished by RNA interference (RNAi) with Csk small interfering RNA. Corresponding effect on aggressive behaviors such as cell migration was also confirmed. Hence, loss of ASPP2 in the choriocarcinoma implicates its crucial role in tumourigenesis. FBI-1 is a transcription factor frequently overexpressed in human cancers. Recently, overexpression of FBI-1 in GTD in association with GTN development was also reported. However, its role in GTD pathogenesis remains elucidated at molecular basis. This study unveiled the ability of FBI-1 in contributing overt aggressiveness in GTD. Ectopic FBI-1 expression resulted in decrease in apoptosis and repression of pro-apoptotic genes such as Bak, Fas and caspase-8 at mRNA level in vitro. FBI-1 overexpression also promoted Akt activation as indicated by Akt-pS473 phosphorylation. Interestingly, effect of FBI-1 on cell motility and invasiveness was eradicated in the presence of specific PI3 kinase inhibitor LY294002. This demonstrated that FBI-1 could promote cell migration and invasion through PI3K/Akt signaling. In summary, this study highlighted the effects of dysregulated ASPP and FBI-1 in apoptosis and aggressiveness, implicating their crucial roles in pathogenesis in GTD. / published_or_final_version / Pathology / Doctoral / Doctor of Philosophy

Gestational trophoblastic disease (GTD) includes a spectrum of diseases that involve abnormal growth of trophoblastic cells inside the uterus. It can range from benign hydatidiform moles (HM) to frankly malignant choriocarcinoma, placental site trophoblastic tumor (PSTT) or epithelioid trophoblastic tumour (ETT).GTD are considered curable if the patient is correctly diagnosed and receive appropriate treatment during the early stage of the disease. About 15% -30% of hydatidiform moles will develop persistent GTD, but majority of them can usually resolved by surgical intervention and post-operation weekly serial serum β-hCG level monitoring. In contrast, choriocarcinoma is a frankly malignant gestational trophoblastic neoplasm (GTN). Most choriocarcinoma arise from HM but can develop from any pregnancy related events such as ectopic pregnancy, live-birth or stillbirth. Being the most aggressive neoplasm in GTD, choriocarcinoma can develop widespread metastasis and can be fatal. FBI-1 (Pokemon) is a transcription factor that is often overexpressed in various types of human cancer. We have reported overexpression of FBI-1 in ovarian cancer in association with cell proliferation and invasiveness. Our recent study also suggested that overexpression of FBI-1 in HM was related to subsequent development of gestational trophoblastic neoplasms(GTN). In this study, we evaluated the role of FBI-1 inchoriocarcinoma cell proliferation. By MTT assay, the proliferation rates of two choriocarcinoma cell lines (JAR and JEG-3) was found to decrease when FBI-1 was downregulated by shRNA approach with statistical significance reached in JEG-3 (p < 0.05). By quantitative real time PCR, the relative levels of a panel of hedgehog pathway related genes, including SHH, SMO, GLI1, GLI2, GLI3, and KIF7 were assessed after knockdown of FBI-1 gene. Sonic hedgehog (SHH) was found to be consistently downregulated in JEG-3 and JAR transfected with FBI-1 shRNA constructs. In conclusion, FBI-1 may play a role in choriocarcinoma cell proliferation and FBI-1 may be explored as a potential therapeutic target for GTD in the future. / published_or_final_version / Pathology / Master / Master of Medical Sciences

Choriocarcinoma is a rare, aggressive malignant epithelial tumor that can be arisen from gestational or non-gestational origins. Gestational choriocarcinoma is found primarily in uterus and is a malignant form of gestational trophoblastic disease. The tumor can easily metastasize to other organs through blood vessels and fatal outcome would be resulted if untreated. Nevertheless, the underlying pathogenesis is not fully explored and understood. FBI-1 is a proto-oncogene and acts as a transcriptional repressor for many cellular processes. Overexpression of FBI-1 was observed in various types of cancers including gestational choriocarcinoma. However, little is known on the mechanisms of regulation of FBI-1 gene expression. In this study, by treating with two epigenetic remodeling drugs, 5-aza-2’-deoxycytidine (5-aza-dc) and trichostatin A (TSA), mRNA and protein expressions of FBI-1 were investigated in gestational choriocarcinoma cell lines, JEG-3 and JAR by using quantitative real-time PCR and western blotting. The morphological changes and cell survival after treatment of 5-aza-dc or TSA on JEG-3 and JAR cell lines was also assessed, the latterby3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyl-2H-tetrazolium bromide (MTT) assay. This study demonstrated that FBI-1 protein was overexpressed in JEG-3 and JAR cells compared to normal trophoblastic cell line. Moreover, FBI-1 expressions in JEG-3 and JAR cells were down-regulated in TSA treatment but remained unchanged in 5-aza-dc treatment. It implies that HDAC inhibitor is able to regulate the expression of FBI-1 gene. After treatment with TSA at 0.3Mor 0.6M, both JEG-3 and JAR cells demonstrated significant morphological changes when comparing with the untreated controls, becoming elongated, distorted, rounder and smalleras well as increasingly detached and floating suggestive of cell death. Such changes were not significantly observed in 5-aza-dctreated cells. In addition, more significant reduction in cell survival as assessed by MTT assay was found in TSA than in 5-aza-dc treatment. This may be related to the decrease inFBI-1 expression after TSA treatment. In summary, histone modification may play a role in the regulation of FBI-1 expression in gestational choriocarcinoma cells affecting the cell survival. / published_or_final_version / Pathology / Master / Master of Medical Sciences

No description available.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1990. / Vita. Abstract. Includes bibliographical references (leaves 194-221). Also available via the Internet