Binding of the Rev protein with Rev Response Element (RRE) RNA present in singly- and unspliced mRNA transcripts is necessary for the replication of HIV-1. This interaction transports the mRNA transcripts from the nucleus to the cytoplasm for translation of the necessary structural and enzymatic proteins for the newly budding virus as well as for providing its genetic material. Given the high rate of mutation in HIV-1, the highly conserved and pertinent RRE RNA is of high interest for pharmaceutical intervention. Consequently, a branched peptide library containing unnatural amino acids was developed to target RRE RNA with the goal of increasing stability, potency, selectivity, and in vivo activity for RRE RNA. An unnatural amino acid branched peptide library (46,656 sequences) was synthesized and screened against RRE IIB and several hits in the sub-micromolar regime were found. A number of hits demonstrated selectivity in the presence of other RNAs in addition to two hits, 4A5 and 4B3, significantly inhibiting HIV-1 growth in vitro. These peptides inhibited HIV-1 replication in a concentration dependent manner and were demonstrated to be non-toxic. Further analysis of 4A5 and 4B3 via footprinting and SHAPE-MaP experiments determined that these peptides blocked binding of Rev through binding at the primary and secondary binding sites of RRE RNA. Sphingosine 1-phosphate (S1P) is a signaling molecule that plays a role in various biological processes including immunity, neurogenesis, and angiogenesis. The role S1P plays is largely determined by its location, in which Spinster homolog 2 (spns2) and mfsd2b are the two known transporters. The two transporters exist in different cell types and cellular localizations, with spns2-produced S1P being responsible for trafficking of lymphocytes. As such, spns2 has become of interest for therapeutic targeting in autoimmune and inflammatory diseases. To validate spns2 as a target in pharmaceutical intervention, a series of spns2 inhibitors were developed. A screening of a library of inhibitors found that compound SLP7120922 demonstrated inhibition of spns2 transport activity. The design, synthesis, and biological evaluation of inhibitors based on SLP7120922 is described. Modifications to the lipophilic tail region were performed with one compound 4.40f discovered to be potent, minimally toxic, and active in vivo. A series of modifications to the head region were then conducted that evaluated linear head derivatives with alkyl-, amide-, and amino acid-based groups. A number of compounds are reported that demonstrate good in vitro activity and minimal toxicity with two compounds, 4.48b and 4.52c, showing favorable in vivo activity in mice. / Doctor of Philosophy / Human immunodeficiency virus (HIV-1) has a high rate of mutation, which commonly leads to the need for many types of medications throughout the lifetime of a patient. In order to design a therapeutic that the virus has a low chance of growing resistance to, a target needs to be chosen with a low mutation rate. One such target is the Rev Response Element (RRE) RNA and it is necessary for the virus to replicate. A protein named Rev binds to RRE RNA in order for RRE to carry out its pertinent function. To block this function we have chosen branched peptides to target the RNA. Peptides are made of the same building blocks of proteins, but are much shorter than proteins. The peptides described here are made up of modified building blocks, called unnatural amino acids. This work describes the generation of an unnatural amino acid branched peptide library and how it was screened in order to find branched peptides that bind RRE RNA. Many peptides were found to bind RRE RNA but two in particular, 4A5 and 4B3, were the best binders that inhibited HIV-1 growth. The remainder of the work describes how these peptides bind to RRE RNA, while demonstrating that they are non-toxic and bind HIV-1 in a concentration dependent manner. A transporter protein termed Spinster homolog 2 (spns2) transports a signaling molecule known as sphingosine 1-phosphate (S1P). For our immune system to function properly, spns2 has to transport S1P to the appropriate places to signal to immune cells. Unfortunately, this is a problem in autoimmune and inflammatory diseases, such as multiple sclerosis, due to these diseases having an overactive immune system. A potential way to treat these diseases would be by inhibiting spns2. This work describes the design, synthesis, and biological evaluation of spns2 inhibitors. Many compounds were found to inhibit spns2 to a degree, but three compounds, in particular, show potent and effective inhibition in mice.

Doctor of Philosophy / In healthy individuals, the autoimmune system is the body's natural defense against foreign materials and organisms. The main tools utilized for this defense mechanism are immune cells. However, in patients suffering from autoimmune diseases, the autoimmune system is overactive resulting in its attack on healthy cells, which leads to reduced or eliminated function of the targeted organs. To suppress these overreactive immune responses, pharmaceutical intervention is needed. An integral part of autoimmune response is the lipid sphingosine-1-phosphate (S1P). Interactions of S1P with its response-inducing receptors prompts the release of immune cells, lymphocytes in particular, from lymph tissue to migrate and participate in the invoked immune response. The pharmaceutical industry has produced five FDA approved drugs that disrupt this S1P-receptor interaction by blocking the receptor to reduce the autoimmune response in patients suffering from autoimmune diseases such as multiple sclerosis and ulcerative colitis. However, these treatments had adverse side effects on the cardiovascular system due to the presence of S1P receptors in the heart. Due to this, there is attraction to target a different node of the S1P signaling pathway to avoid these side effects while still suppressing the immune response. A node that is a viable target for therapeutic target that has recently become the focus of medicinal chemistry campaigns is the transporter protein spinster homolog 2 (Spns2). This protein is responsible for the transport of S1P from intracellular space to extracellular space to interact with its receptors and induce the immune response. Recently, our group has developed several effective inhibitors of Spns2. In this dissertation, several improvements of previously reported inhibitors are revealed. The pinnacle of this work is the development of 4.22v that is optimized to have drug-like properties for testing in mice. Administration of 4.22v to mice resulted in reduced circulating lymphocytes and without showing signs of toxicity following chronic dosing for 14 days. These results suggest that 4.22v is a potential drug candidate and is currently undergoing further biological evaluation.

The potential antitumor activity of mixed CB1/CB2 cannabinoid receptor agonists, such as the aminoalkylindole WIN55,212-2 (WIN2), has been extensively studied, but little information is available as to their potential interaction with conventional cancer therapies, such as ionizing radiation (IR). In the present work, we investigated the effects of WIN2 on the antiproliferative effects of radiation in human (MCF-7 and MDA-MB-231) and murine (4T1) breast cancer cells, as well as an immortalized human breast epithelial cell line (MCF-10A). WIN2 or radiation alone inhibited breast tumor growth, while the combination of WIN2 and radiation was more effective than either agent alone in breast cancer cells. WIN2 showed lower potency in MCF-10A cells than MCF-7 cells, but was still able to augment the effects of radiation at higher doses. The stereoisomer of WIN2, WIN55,212-3 (WIN3) failed to inhibit growth or potentiate the growth-inhibitory effects of radiation, indicating stereospecificity in all cell lines tested. The combination of WIN2 and IR was examined in vivo but the results were inconclusive. Interestingly, while other aminoalkylindoles, pravadoline and JWH-015, enhanced the antiproliferative effects of radiation, this was not the case for other synthetic cannabinoids (i.e., nabilone, CP55,940 and methanandamide) or phytocannabinoids (i.e., ∆9-tetrahydrocannabinol and cannabidiol). The antiproliferative actions of WIN2 were not ameliorated by CB1, CB2, TRPV1, or PPAR receptor antagonists, suggesting the possibility of a novel site of action. Studies utilizing sphingosine-1-phosphate (S1P) agonists and estradiol suggest that WIN2 interferes with S1P signaling in cell proliferation, but agonist stimulated [³⁵S]GTPγS binding assays show that this antagonism is not occurring at the level of S1P receptors. In addition, WIN2 did not alter radiation-induced DNA damage or the rate of DNA repair based on γH2AX staining. Treatment with WIN2 and radiation promoted both autophagy and senescence, but not apoptosis or necrosis. Time course studies combined with senescence and cell death data suggest that radiation-induced senescence, while WIN2 induced classical growth arrest and the WIN2/IR combination produced parallel mechanisms of both senescent growth arrest and classical growth arrest. Taken together, these findings raise the possibility that aminoalkylindole compounds targeting a novel site of action represents a potential strategy to augment the effectiveness of radiation treatment in breast cancer.

Introdução: A lipoproteína de baixa densidade (LDL) e suas formas oxidadas (LDLox) possuem múltiplas propriedades aterogênicas, atuando na deposição de colesterol, indução e manutenção da inflamação, disfunção endotelial, surgimento de células espumosas na parede arterial e conseqüente formação da placa de ateroma. Adicionalmente, LDLox induz apoptose de células endoteliais humanas (HMEC). A lipoproteína de alta densidade (HDL) possui inúmeras atividades antiaterogênicas, incluindo ações antioxidante, anti-inflamatória e anti-trombótica. A HDL é capaz de proteger as HMEC contra apoptose. As subfrações de HDL (sHDL) são heterogêneas em sua composição físico-química e atividades biológicas. A atividade antioxidante das sHDL aumenta com a densidade (HDL2b<HDL2a<HDL3a<HDL3b <HDL3c) e está deficiente em pacientes com SMet. Contudo, a heterogeneidade da atividade anti-apoptótica das sHDL é ainda desconhecida. Objetivos: (i) avaliar a heterogeneidade da atividade protetora das sHDL de indivíduos normolipidêmicos (n=7) e de pacientes com SMet (n=16) contra apoptose de HMEC induzida por LDLox; (ii) definir os mecanismos moleculares envolvidos nesta atividade. Métodos: Através de ultracentrifugação por gradiente de densidade, isolamos cinco diferentes sHDL. HMEC foram incubadas com LDLox (200 ?g apoB/ml) na presença ou não das sHDL (5-100 ?g proteína/ml). Os marcadores de toxicidade (MTT) e de apoptose celular (microscopia de fluorescência, marcagem com anexina V, cit c, AIF, degradação Bid, atividade caspase-3 e fragmentação do ADN) foram analisados. Resultados: Todas sHDL protegeram as HMEC contra a toxicidade e apoptose induzidas pela LDLox. Com mesma concentração de proteína, as subfrações HDL3c (60% proteção - MTT - e >100% - anexina V) e 3b (43% e 67%, respectivamente) de indivíduos normolipidêmicos apresentaram atividade anti-apoptótica mais potente do que as subfrações HDL2a (29% e 28%; p<0,01 vs. HDL3c, respectivamente) e 2b (25% e 62%; p<0,001 vs. HDL3c, respectivamente). Todas sHDL reduziram geração de espécies reativas de oxigênio (ROS) induzida pela LDLox, sendo a HDL3c (54%) mais potente do que HDL2b (21%; p<0.05 vs. HDL3c). Houve correlação positiva entre as atividades anti-apoptótica e antioxidante intracelular com conteúdo de apoA-I e esfingosina 1-fosfato (E1F) das sHDL, senda HDL3b e 3c ricas em E1F. A atividade anti-apoptótica da E1F e das sHDL parece depender da interação com as células endoteliais via apoA-I e seu receptor SR-BI. Finalmente, as HDL3c (n=5) isoladas de pacientes com SMet possuem conteúdo significativamente menor de apoA-I e reduzida atividade anti-apoptótica (60%, p<0,01), quando comparada aos controles normolipidêmicos (n=5). Houve tendência à diminuição da proteção contra a geração de ROS (SMet, n=10). Conclusão: As subfrações HDL3c protegem de forma potente as células endoteliais humanas contra toxicidade e apoptose induzidas pela LDLox, assim como contra geração de ROS. Esta atividade antiapoptótica está reduzida na SMet. / Background: Low density lipoprotein (LDL) and its oxidized forms (oxLDL) have several atherogenic properties, including cholesterol deposition, inflammation, endothelial dysfunction and foam cell formation on the arterial wall, leading to atherosclerotic plaque development. In addition, oxLDL induces human endothelial cell apoptosis (HMEC). High-density lipoprotein (HDL) has number of antiatherogenic activities, as antioxidative, anti-inflammatory and anti-thrombotic actions. HDL displays anti-apoptotic activity and is able to protect endothelial cells against oxLDL-induced apoptosis. HDL subfractions (sHDL) are highly heterogeneous in their physical and chemical composition and biological functions. Antioxidative activity of HDL subfractions increases with increment in density, HDL2b<HDL2a<HDL3a<HDL3b <HDL3c. Important, HDL subfractions from subjects with metabolic syndrome (MetS), display a significantly lower antioxidative activity as compared to healthy controls. However, the heterogeneity of their anti-apoptotic activity was not demonstrated. Objectives: (i) to evaluate the heterogeneity of antiapoptotic activity of sHDL from normolipidemic controls (n=7) and MetS patients (n=16) towards oxLDL-induced apoptosis of HMEC; (ii) to define molecular mechanisms involved in this anti-apoptotic action. Methods: Five major sHDL were fractionated by density gradient ultracentrifugation. HMEC were incubated with mildly oxLDL (200 ?g apoB/ml) in the presence or absence of each sHDL (5-100 ?g protein/ml). Markers of cellular toxicity (MTT) and apoptosis (fluorescent nucleic acid staining, annexin V binding, cytochrome c, AIF and Bid, caspase-3 activity and DNA fragmentation) were observed. Results: All HDL subfractions isolated from normolipidemic subjects protected HMEC against oxLDL-induced toxicity and apoptosis. At equal protein concentrations, HDL3c (60% protection in the MTT test; >100% in annexin V biding) and 3b subfractions (43% and 67%, respectively) were more potent against oxLDL-induced toxicity and apoptosis as compared to HDL2a (29% and 28%; p<0.01 vs. HDL3c, respectively) and 2b subfractions (25% and 62%; p<0.001 vs. HDL3c, respectively). All HDL subfractions attenuated of reactive oxygen species (ROS) generation in HMEC induced by oxLDL. Again, HDL3c (54% inhibition) were more potent as compared to HDL2b (21%; p<0.05 vs. HDL3c). The anti-apoptotic and intracellular antioxidative activities of HDL3 were positively correlated with apoA-I and sphingosine 1-phosphate (S1P) content of sHDL and, possibly, depend on their cellular interaction through apoA-I and its SR-BI receptor. The sHDL3c isolated from MetS patients (n=5) possess reduced content of apoA-I and less potent anti-apoptotic activity (-60%, p<0.01) than controls (n=5). Conclusion: Normolipidemic small dense HDL3 provide potent protection of human endothelial cells from oxLDL-induced apoptosis; this anti-apoptotic activity is reduced in the MetS.

L'activation dérégulée de lymphocytes T conduit à une réponse immune délétère envers les antigènes du soi. Malgré une utilisation croissante de doses élevées d'IVIg pour traiter les maladies auto-immunes, la compréhension des mécanismes sous-jacents aux bénéfices thérapeutiques demeure un enjeu majeur. En effet, les effets des IVIg restent inexplorés dans le cadre des maladies auto-immunes associées aux lymphocytes T. J'ai recherché les effets de doses élevées d'IVIg dans la polarisation des lymphocytes T en utilisant le modèle de l'encéphalomyélite auto-immune expérimentale (EAE), une maladie auto-immune associée aux lymphocytes T. Les IVIg inhibent la différenciation des lymphocytes T CD4+ naïfs en sous-populations effectrices (lymphocytes Th1 et Th17) et induisent, de manière concomitante, une prolifération des lymphocytes T Foxp3+. Les IVIg diminuent les effets délétères des lymphocytes T sur les tissus en diminuant l'expression du GM-CSF et de la podoplanine. En outre, les IVIg empêchent la dégénérescence neuronale en inhibant l'infiltrat en lymphocytes T CD4+ dans le système nerveux central (SNC). Ce mécanisme passe par une séquestration de ces lymphocytes dans les ganglions lymphatiques drainants à travers la voie de signalisation S1P-S1P1-mTor. De manière intéressante, et contrairement aux données actuelles, le récepteur inhibiteur FcγRIIB et la sialylation des IVIg ne sont pas indispensables pour la modulation des sous-populations de lymphocytes T CD4+ effecteurs et régulateurs induite par les IVIg. Ainsi, le bénéfice thérapeutique des IVIg dans le modèle de l'EAE implique un déséquilibre de la balance entre les lymphocytes Th17/Th1 et les lymphocytes Trég, au profit des lymphocytes Trég. Ces cellules diminuent l'expression de médiateurs favorisant l'apparition de l'encéphalomyélite et inhibent la migration des lymphocytes T vers l'organe cible.

The imidazoline I1 receptor (I1-R) is a novel receptor found primarily in the brain and nervous tissue where it modulates neurotransmission. It is named for its high affinity for compounds with an imidazoline structure such as the anti-hypertensive drugs, clonidine and moxonidine. The imidazoline receptor antisera-selected protein (IRAS) is the putative clone of the I1-R. IRAS has a unique structure, which does not resemble any other receptor protein. IRAS is present throughout the body with highest levels in the brain. There is a growing body of research examining the physiological roles of IRAS as an I1-R, in cell survival, migration and protein trafficking. However, there is little research into its neuronal functions. IRAS interacts with other membrane receptors: the mouse homologue of IRAS reorganises the actin cytoskeleton through interaction with the α5β1 fibronectin receptor. IRAS also binds insulin receptor substrate 4 and enhances insulin-induced extracellular signal-regulated kinase1/2 (ERK1/2) activation. Actin reorganisation and ERK1/2 activation are important for the development of neurites during neuronal differentiation. Therefore, the work described in this thesis aimed to investigate the effects of IRAS on neuronal differentiation. Studies reported in this thesis also aimed to investigate whether IRAS affected ERK1/2 signalling of other receptors involved in neuronal differentiation such as the NGF receptor, TrkA, and lysophospholipid receptors. The above aims were carried out in neuronal model PC12 cells transfected with either IRAS or a vector plasmid. Fluorescence microscopy and Western blotting techniques were used to examine the effect of IRAS on cell morphology and ERK1/2 signalling. The work described in this thesis found that IRAS reorganises the actin cytoskeleton and enhances growth cone development in PC12 cells. This study also shows that IRAS differentially enhances or inhibits NGF-induced PC12 cell differentiation depending on the presence or absence of serum in the media. In full-serum conditions, IRAS enhanced neurite outgrowth and this was accompanied by an increase in ERK1/2 activation. In serum-starved cells, IRAS inhibited neurite outgrowth with similar levels of ERK1/2 activation observed in vector- and IRAS-transfected cells. Finally, studies presented in this thesis found that IRAS enhances lysophosphatidic acid-induced ERK1/2 activation and that IRAS interacting with lysophospholipid receptor agonists present in serum is a potential mechanism by which it enhances NGF-induced ERK1/2 activation in full-serum conditions. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1345359 / Thesis (Ph.D.) - University of Adelaide, School of Medical Sciences, 2008

Introdução: A lipoproteína de baixa densidade (LDL) e suas formas oxidadas (LDLox) possuem múltiplas propriedades aterogênicas, atuando na deposição de colesterol, indução e manutenção da inflamação, disfunção endotelial, surgimento de células espumosas na parede arterial e conseqüente formação da placa de ateroma. Adicionalmente, LDLox induz apoptose de células endoteliais humanas (HMEC). A lipoproteína de alta densidade (HDL) possui inúmeras atividades antiaterogênicas, incluindo ações antioxidante, anti-inflamatória e anti-trombótica. A HDL é capaz de proteger as HMEC contra apoptose. As subfrações de HDL (sHDL) são heterogêneas em sua composição físico-química e atividades biológicas. A atividade antioxidante das sHDL aumenta com a densidade (HDL2b<HDL2a<HDL3a<HDL3b <HDL3c) e está deficiente em pacientes com SMet. Contudo, a heterogeneidade da atividade anti-apoptótica das sHDL é ainda desconhecida. Objetivos: (i) avaliar a heterogeneidade da atividade protetora das sHDL de indivíduos normolipidêmicos (n=7) e de pacientes com SMet (n=16) contra apoptose de HMEC induzida por LDLox; (ii) definir os mecanismos moleculares envolvidos nesta atividade. Métodos: Através de ultracentrifugação por gradiente de densidade, isolamos cinco diferentes sHDL. HMEC foram incubadas com LDLox (200 ?g apoB/ml) na presença ou não das sHDL (5-100 ?g proteína/ml). Os marcadores de toxicidade (MTT) e de apoptose celular (microscopia de fluorescência, marcagem com anexina V, cit c, AIF, degradação Bid, atividade caspase-3 e fragmentação do ADN) foram analisados. Resultados: Todas sHDL protegeram as HMEC contra a toxicidade e apoptose induzidas pela LDLox. Com mesma concentração de proteína, as subfrações HDL3c (60% proteção - MTT - e >100% - anexina V) e 3b (43% e 67%, respectivamente) de indivíduos normolipidêmicos apresentaram atividade anti-apoptótica mais potente do que as subfrações HDL2a (29% e 28%; p<0,01 vs. HDL3c, respectivamente) e 2b (25% e 62%; p<0,001 vs. HDL3c, respectivamente). Todas sHDL reduziram geração de espécies reativas de oxigênio (ROS) induzida pela LDLox, sendo a HDL3c (54%) mais potente do que HDL2b (21%; p<0.05 vs. HDL3c). Houve correlação positiva entre as atividades anti-apoptótica e antioxidante intracelular com conteúdo de apoA-I e esfingosina 1-fosfato (E1F) das sHDL, senda HDL3b e 3c ricas em E1F. A atividade anti-apoptótica da E1F e das sHDL parece depender da interação com as células endoteliais via apoA-I e seu receptor SR-BI. Finalmente, as HDL3c (n=5) isoladas de pacientes com SMet possuem conteúdo significativamente menor de apoA-I e reduzida atividade anti-apoptótica (60%, p<0,01), quando comparada aos controles normolipidêmicos (n=5). Houve tendência à diminuição da proteção contra a geração de ROS (SMet, n=10). Conclusão: As subfrações HDL3c protegem de forma potente as células endoteliais humanas contra toxicidade e apoptose induzidas pela LDLox, assim como contra geração de ROS. Esta atividade antiapoptótica está reduzida na SMet. / Background: Low density lipoprotein (LDL) and its oxidized forms (oxLDL) have several atherogenic properties, including cholesterol deposition, inflammation, endothelial dysfunction and foam cell formation on the arterial wall, leading to atherosclerotic plaque development. In addition, oxLDL induces human endothelial cell apoptosis (HMEC). High-density lipoprotein (HDL) has number of antiatherogenic activities, as antioxidative, anti-inflammatory and anti-thrombotic actions. HDL displays anti-apoptotic activity and is able to protect endothelial cells against oxLDL-induced apoptosis. HDL subfractions (sHDL) are highly heterogeneous in their physical and chemical composition and biological functions. Antioxidative activity of HDL subfractions increases with increment in density, HDL2b<HDL2a<HDL3a<HDL3b <HDL3c. Important, HDL subfractions from subjects with metabolic syndrome (MetS), display a significantly lower antioxidative activity as compared to healthy controls. However, the heterogeneity of their anti-apoptotic activity was not demonstrated. Objectives: (i) to evaluate the heterogeneity of antiapoptotic activity of sHDL from normolipidemic controls (n=7) and MetS patients (n=16) towards oxLDL-induced apoptosis of HMEC; (ii) to define molecular mechanisms involved in this anti-apoptotic action. Methods: Five major sHDL were fractionated by density gradient ultracentrifugation. HMEC were incubated with mildly oxLDL (200 ?g apoB/ml) in the presence or absence of each sHDL (5-100 ?g protein/ml). Markers of cellular toxicity (MTT) and apoptosis (fluorescent nucleic acid staining, annexin V binding, cytochrome c, AIF and Bid, caspase-3 activity and DNA fragmentation) were observed. Results: All HDL subfractions isolated from normolipidemic subjects protected HMEC against oxLDL-induced toxicity and apoptosis. At equal protein concentrations, HDL3c (60% protection in the MTT test; >100% in annexin V biding) and 3b subfractions (43% and 67%, respectively) were more potent against oxLDL-induced toxicity and apoptosis as compared to HDL2a (29% and 28%; p<0.01 vs. HDL3c, respectively) and 2b subfractions (25% and 62%; p<0.001 vs. HDL3c, respectively). All HDL subfractions attenuated of reactive oxygen species (ROS) generation in HMEC induced by oxLDL. Again, HDL3c (54% inhibition) were more potent as compared to HDL2b (21%; p<0.05 vs. HDL3c). The anti-apoptotic and intracellular antioxidative activities of HDL3 were positively correlated with apoA-I and sphingosine 1-phosphate (S1P) content of sHDL and, possibly, depend on their cellular interaction through apoA-I and its SR-BI receptor. The sHDL3c isolated from MetS patients (n=5) possess reduced content of apoA-I and less potent anti-apoptotic activity (-60%, p<0.01) than controls (n=5). Conclusion: Normolipidemic small dense HDL3 provide potent protection of human endothelial cells from oxLDL-induced apoptosis; this anti-apoptotic activity is reduced in the MetS.

No description available.

High grade aggressive lymphomas have high mortality. By their nature, more than 40% of patients die from these diseases even with the improved treatment strategies currently available for oncology patients. The characteristic feature is that they are functionally heterogeneous and therefore have different biological and molecular signatures which make it difficult for all groups to respond to same line of treatment. Based on the above, I set out to look at the impact of viral and cellular gene products on these groups of diseases: In chapter 3 I developed monoclonal antibodies against HERV‐K10. I subsequently investigated their expressions in aggressive lymphomas including Diffuse Large B‐cell lymphoma, Hodgkin’s lymphoma and Primary CNS lymphomas. I showed HERV‐K10 is expressed in cell lines of aggressive lymphomas, but not in paraffin‐embedded tissues. In chapter 4 I showed that the expression of ATM using immune‐histochemistry techniques in aggressive lymphomas does offer a guide to prognosis and treatment. Nearly 30% of Diffuse Large B‐cell lymphomas express ATM, 55% of Hodgkin’s lymphomas and more than 80% of Primary CNS lymphomas. I also showed there is a correlation of ATM expression and EBV‐driven aggressive lymphomas and that this has a poor prognostic significance. Chapter 5 analysed the results obtained by generating, validating and evaluating data base of DLBCL and PCNSL from a retrospective cohort over a 17‐year period. The results confirmed that prognostic indicators including ATM, S1PR2, Autotaxin and EBV using immuno‐histochemistry techniques help with categorising aggressive lymphomas into different prognostic groups and does influence future management. In summary, my results showed there is a critical place for immuno‐histochemistry techniques in convincingly helping understand the expressions of viral and cellular gene products in aggressive lymphomas and in contributing positively to their management.

Cholangiocarcinoma (CCA) has a high mortality rate and its occurrence is rising. This increase prompts the need for improved CCA treatments. Studies have suggested that CCA is highly reliant on the sphingosine-1-phosphate-receptor-2 (S1PR2) and sphingosine kinase 2 (SphK2). Recently, a competitive SphK2 inhibitor, ABC294640, has been approved for clinical trial. ABC294640 has the potential to treat CCA, which is support by a phase I clinical study that was able to temporarily treat a patient suffering from metastasized CCA with ABC294640. To determine the viability of ABC294640 as a treatment for CCA, this study focused on determining the effects of ABC294640 on rat CCA cell lines. We found that ABC294640 inhibited the growth and migration of CCA and CAFs cells. The growth and count of 3-D organotypic co-culture of CCA and CAFs, which forms the “duct-like” structures, were reduced by ABC294640. The potential of inhibiting SphK2 as a treatment for CCA is supported by our finding of increased expression of S1PR2 and SphK2 in CCA patient liver samples. In conclusion, ABC294640 represents a potential therapeutic agent for CCA.