SerpinB2 (aka plasminogen activator type 2) is well described as an extracellular inhibitor of urokinase-type plasminogen activator (uPA). However, the majority of SerpinB2 is retained intracellularly, and many uPA-independent activities have been reported for SerpinB2 suggesting an alternate function. This thesis explores the role of SerpinB2 in epithelial tumour cell lines, highlights the problems associated with various expression systems and argues that SerpinB2 has no role in growth or apoptosis of tumour cells. A potential role for immune modulation and angiogenesis is suggested in in vivo models. Previous research using SerpinB2 transfected, clonally selected tumour cell lines suggested that SerpinB2 regulates the retinoblastoma tumour suppressor protein (Rb) by binding and protecting Rb from degradation. Despite the use of two techniques under numerous conditions and positive controls, no significant interaction between SerpinB2 and Rb was found. SerpinB2 was reported to bind Rb through a PENF homology motif located within the SerpinB2 C-D interhelical loop region. The PENF homology motif was postulated to represent the motif responsible for binding to the C-pocket of Rb. Epstein Barr Virus nuclear antigen 6 (EBNA6) is a known Rb binding protein, which contains two predicted PENF homology motifs. However, mutation of the two PENF homology motifs within EBNA6 did not reduce Rb binding. Furthermore, the SerpinB2 PENF homology motif is actually not well conserved between SerpinB2 proteins from multiple species, whereas other regions of the SerpinB2 C-D loop show a high level of conservation. These data do not support a role for SerpinB2 and the PENF homology motif in Rb binding. SerpinB2 has been proposed to have a role in regulating growth and apoptosis. To further investigate this proposed phenotype of SerpinB2, SerpinB2 was expressed in a range of epithelial tumour lines using transient transfection. No change in growth, apoptosis or Rb levels were found. After ≈2-3 month antibiotic selection for the SerpinB2-expressing plasmid, SerpinB2 protein was lost without the loss of the transgene, indicating selective pressure against long-term SerpinB2 protein expression. To further investigate long-term SerpinB2 expression adenovirus and lentivirus vectors were used. Infection of tumour cell lines with adenovirus vectors expressing SerpinB2 resulted in reduced cell growth, characterised by increased p53 (but not Rb) levels and G2 arrest or apoptosis. When SerpinB2 expressing lentivirus vectors were used to transduce the same tumour cell lines, high levels of long-term expression of functional SerpinB2 was achieved. However, SerpinB2-expressing cell lines showed no differences in growth, proliferation, Rb levels, or apoptosis induced by a range of agents. Growth and apoptosis observed with adenovirus SerpinB2 had all the characteristics of adenovirus-associated toxicity, which has been reported previously for specific proteins. These experiments highlighted the problems associated with SerpinB2 expression systems and suggest that SerpinB2 expression per se is not toxic nor has a role in regulating Rb, growth and apoptosis. Screening of a number of tumour cell lines identified the HPV16 transformed cervical cancer line as expressing high levels of SerpinB2. SerpinB2 was located both extracellularly and intracellularly with a cytoplasmic and nuclear distribution. A high molecular weight SerpinB2 species was identified in CaSki cells and was shown to be the N-linked glycosylated species. Sequencing showed the protein to be Type A SerpinB2 and the protein was shown to form an inhibitory complex with uPA. An abundant low molecular weight SerpinB2 species was also identified in CaSki cell supernatants and appeared to be a proteolytic fragment of SerpinB2. Treatment of CaSki with PMA, TNFα and IFNγ increased SerpinB2 levels. Lentiviral based shRNA failed to significantly down regulate SerpinB2 expression and increasing SerpinB2 levels with lentiviral expression did not change growth, apoptosis, Rb levels or E7 transcription. Lentiviral expression of SerpinB2 in (normally SerpinB2 negative) HPV16 transformed SiHa cells, also failed to show changes in Rb levels or E7 transcription. CaSki thus express wild-type and functional SerpinB2, but no evidence could found that SerpinB2 effects HPV16 E7 transcription or Rb levels. The data presented identifies CaSki as valuable source of biologically functional SerpinB2. SerpinB2 expression in breast cancer cells has been associated with positive prognosis. Tubo, a SerpinB2-negative murine breast carcinoma cell line, was transduced with lentivirus expressing SerpinB2 and grown subcutaneously in BALB/c mice. SerpinB2 expressing tumours appeared red and were larger than control tumours. Furthermore, SerpinB2 expressing tumours had a ≈2 fold higher density of blood vessels when compared to Tubo and Tubo expressing EGFP. Mice carrying tumours expressing SerpinB2 also showed reduced anti-tumour IgG2 responses. These data suggest that a role for SerpinB2 in regulating angiogenesis and antitumour immunity. In conclusion, this thesis challenges the notion that SerpinB2 regulates Rb, cell cycle, and apoptosis and suggests a potential role for SerpinB2 in tumour angiogenesis and immunity.

<p>Heparan sulfate (HS) is a polysaccharide of glycosaminoglycan type composed of alternating hexuronic acid [either glucuronic acid (GlcA) or iduronic acid (IdoA)] and glucosamine (GlcN) units that can be sulfated in various positions. HS binds to a large number of proteins and these interactions promote many biological processes, including cell adhesion and growth factor signaling. This thesis deals with the structural analysis of short heparan sulfate sequences that mediate binding to fibroblast growth factors FGF1 and FGF2, their receptor FGFR4, and the angiogenesis inhibitor endostatin.</p><p>Both FGF1 and FGF2 were shown to interact with N-sulfated hexa- and octasaccharide fragments isolated from HS. A pool of HS fragments depleted for FGF1 binding retained the ability to bind FGF2. Changes in 6-O sulfation affected binding to FGF1 but not FGF2, indicating that these proteins bind to distinct HS sequences. </p><p>All octasaccharides with high affinity for FGF1 contained an internal IdoA2S-GlcNS6S-IdoA2S trisaccharide motif as shown by exoenzyme-based sequence analysis. FGF2 bound to a mono-O-sulfated hexasaccharide with an internal IdoA2S unit, although the affinity was higher for a di-O-sulfated octasaccharide displaying an IdoA2S-GlcNS-IdoA2S trisaccharide motif. </p><p>FGFR4 was shown to bind the HS analogue heparin with a K_D value of 0.3 μM.</p><p>The interaction between FGFR4 and HS depends on both IdoA2S and GlcNS6S units. Sequence analysis suggested that the number but not the precise location of 6-O-sulfate groups determines affinity.</p><p>The HS-binding site of endostatin was identified through alanine scanning. Endostatin mutants with reduced affinity for HS were unable to counteract angiogenesis induced by FGF2. The predominant HS motif recognized by endostatin was shown to consist of two N-sulfated domains separated by N-acetylglucosamine units.</p>

<p>Angiogenesis can be defined as the formation of new blood vessels from pre-existing ones. Angiogenesis is required for development and maintenance of our vascular system and thus of fundamental importance to our existence. The endothelial cells that line the inside of the vessels de-differentiate, migrate, proliferate and re-differentiate during angiogenesis. Angiogenesis is tightly regulated, controlled by several angiogenic factors of various classes that promote angiogenesis but also by anti-angiogenic factors that counteract the effect of the pro-angiogenic factors. We have examined three factors involved in angiogenesis regulation, Vascular endotelial growth factor (VEGFR) -3, the matrix protein laminin-1 and the collagen XVIII derived fragment endostatin. </p><p>Five tyrosine phosphorylation sites in the cytoplasmic tail of VEGFR-3 were identified by phosphopeptide mapping (PPM). The data was confirmed by PPM using point-mutated receptors generated by site-directed mutagenesis.</p><p>Laminin-1 was found to promote angiogenesis in the chicken chorioallantoic membrane assay and in a synergistic fashion together with suboptimal levels of fibroblast growth factor 2 (FGF-2) in embryoid bodies. Laminin-1 also promoted endothelial tubular morphogenesis in vitro, and upregulated the expression of the endothelial differentiation marker Jagged-1. </p><p>Endostatin was shown to affect endothelial FGF-2-induced cell survival and morphogenesis. This was a result of direct binding to endothelial cells and induction of tyrosine phosphorylation of many proteins including the adaptor protein Shb. The apoptotic and morphogenic responses induced by endostatin was shown to be dependent on Shb. Further, endostatin inhibited endothelial migration and affected molecules implicated in migration. In particular, FGF-2 induced actin reorganization, and β-catenin regulation was modulated by endostatin. </p>

<p>Neuroblastoma is one of the most common solid cancers of early childhood. In Sweden, approximately 10-15 cases occur annually. The overall five-year neuroblastoma survival in Europe is approximately 45%. Since cancer treatment involves drugs with risks of side effects in the growing child, there is a need for more effective and less toxic drugs. One new approach in cancer treatment is inhibition of tumor angiogenesis, i.e., of new blood vessel growth into the tumor. An angiogenesis inhibitor may be combined with cytostatic drugs to enhance the efficacy. The aim of this study was to investigate how drugs could be used to inhibit angiogenesis and tumor growth in a xenograft model of human neuroblastoma in nude mice. </p><p>The tumors express the angiogenesis stimulator vascular endothelial growth factor (VEGF) on both protein and mRNA levels. The angiogenesis inhibitors SU5416 (an inhibitor of VEGF signalling) and TNP-470 (an inhibitor of endothelial cell proliferation) inhibited angiogenesis in our model. TNP-470, however, inhibited angiogenesis without significant reduction of the tumor growth, in contrast to SU5416. </p><p>We also discovered that the cytostatic drug CHS 828 could cause regression of neuroblastoma tumors in the model when given orally at a low daily dose, alone or in combination with the angiogenesis inhibitor SU5416 or TNP-470. </p><p>Furthermore, a new use of the cardiac glycoside digoxin was found. Digoxin inhibited FGF-2 -stimulated bovine capillary endothelial cell growth in vitro, and inhibited angiogenesis in vivo in the chick chorioallantoic membrane assay (CAM). It also inhibited neuroblastoma growth by approximately 50% in our neuroblastoma model. </p><p>In conclusion, CHS 828 and digoxin represent two classes of drugs with potent antitumor effects that may be valuable in treatment of neuroblastoma, either alone or in combination with angiogenesis inhibitors.</p>

<p>Angiogenesis is necessary for the growth and spread of solid tumors. In these studies angiogenesis was measured in childhood malignancies in general and in Wilms’ tumor in particular, and cutting needle biopsy (CNB) specimens were evaluated for diagnosis in childhood renal tumors. </p><p>In 33 patients with Wilms’ tumor, tumor capillaries were quantified, expression of angiogenic growth factors in tumor tissue investigated, and concentrations of angiogenic growth factors in serum measured. Reference values for angiogenic growth factors were obtained in 80 healthy adults (fibroblast growth factor 2 [FGF-2], vascular endothelial growth factor A [VEGF-A]) and 94 healthy children (angiogenin [ANG], epidermal growth factor [EGF], FGF-2, hepatocyte growth factor [HGF], tumor necrosis factor alpha [TNFA] and VEGF-A) aged 0.5-18 years. These reference values were compared with values in sera taken at diagnosis in 268 children with tumors and leukemias. CNB specimens were evaluated in 25 children with renal tumors.</p><p>A large number of capillaries was an independent prognostic factor for a poor outcome in Wilms’ tumor. Angiogenic growth factors were expressed in Wilms’ tumor tissue, and elevated concentrations of HGF and VEGF-A were found in both benign and malignant tumors. HGF was increased in leukemia, and TNFA was increased in leukemia, lymphoma and neuroblastoma. CNB, which proved to be a safe procedure, had a sensitivity of 76%. </p><p>These studies have demonstrated that quantification of capillaries is a prognostic factor in Wilms’ tumor and that HGF, TNFA and VEGF-A are frequently elevated in sera from children with cancer. Quantification of capillaries in tumor tissue and of circulating angiogenic growth factors would therefore seem to be of clinical relevance in managing children with cancer.</p>

<p>This thesis investigated the predictive and the prognostic powers of angiogenesis related markers in both operable and inoperable non-small cell lung cancer (NSCLC) patients.</p><p>In the first and second study, we investigated the serological fractions of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in 2 cohorts of patients with either operable or inoperable NSCLC. </p><p>Regarding operable NSCLC, we demonstrated significant correlations between VEGF and tumour volume and overall survival. Regarding bFGF, significant correlations with recurrent disease and survival were demonstrated. VEGF and bFGF correlated to each other and with platelet counts. In multivariate analysis, bFGF proved to be a significantly independent prognostic factor.</p><p>Regarding inoperable NSCLC, we demonstrated that patients with elevated bFGF levels before any treatment and during chemotherapy had a significantly poorer survival. During chemotherapy, each rise of one unit of bFGF (ng/L) corresponded to a 4 times increased risk of death. Regarding VEGF, elevated levels after radiotherapy corresponded with better survival. All prognostic information demonstrated in this study concerned patients with a, co-sampled, normal platelet count.</p><p>In the third study, three putative markers, HER-2, EGFR and COX-2, suitable for targeted therapies in resected NSCLC were investigated in a panel of 53 tumours and further investigated for a possible correlation with microvessel density. We demonstrated that HER-2 and COX-2 were mainly expressed in adenocarcinomas, whereas EGFR was only expressed in squamous cell carcinomas. COX-2 showed a trend towards a correlation with microvesssel density. The expression profile, HER-2+/EGFR-, was significantly correlated to poorer survival. </p><p>In the fourth study, a predictive model for recurrences consisting of p53, CD34 and CD105, and circulating serum fractions of VEGF and bFGF, was investigated. The two endothelial markers correlated with each other. CD105 expression correlated with p53 expression. No other significant correlations between markers could be demonstrated. A significant correlation between p53 overexpression and recurrent disease was demonstrated. The mutational status could not confirm the immunohistochemical correlation between p53 and recurrences. </p><p> In conclusion, the present thesis demonstrates that the angiogenic factors VEGF and bFGF analysed in sera have both predictive and prognostic information when measured in operable and inoperable NSCLC. Since HER-2 is overexpressed in NSCLC and linked with prognostic information, this marker might be a suitable target for therapy in NSCLC. Furthermore, in patients with operable NSCLC, p53 expression status was linked with recurrent disease and mean MVD. </p>

<p>Heparan sulfate (HS) is an unbranched and negatively charged polysaccharide of the glycosaminoglycan family, based on the repeated (GlcNAcα1-4GlcAβ1-4)disaccharide structure. The HS backbone is modified by epimerization and sulfation in various positions. HS chains are composed of <i>N</i>-sulfated (NS) domains – predominant locations for further modification steps –, the poorly modified <i>N</i>-acetylated (NA) domains and the alternating NA/NS-domains. HS is present at the cell surface and in the extra-cellular matrix and interacts at these sites with various proteins involved in numerous biological processes, such as angiogenesis. Both pro- and anti-angiogenic proteins can interact with HS and this study was focused on how HS binds to the anti-angiogenic proteins endostatin (ES) and histidine-rich glycoprotein (HRGP) and to pro-angiogenic fibroblast growth factors (FGFs).</p><p>Here we show that ES recognizes NS-domains in HS spaced by NA-disaccharides, and that binding to ES is abolish through cleavage at these NA-disaccharides. HRGP335, a peptide derived from the His/Pro-rich domain of HRGP is shown to bind to heparin and HS to the same extent as full-size HRGP, in a Zn²⁺-dependent manner. Moreover, the ability of HRGP to inhibit endothelial cell migration is located to the same region of the protein. We analyzed HS structure in respect to binding to HRGP335 and FGF-2, and show that the ability of HS to bind to those proteins depends on chain length and composition. Finally, the role of HS in FGF–HS–FGF receptor ternary complexes is evaluated using biosynthetic analogs of NS-domains. For stabilization of such complexes the overall sulfation degree of HS seems to play a more pronounced role than the exact distribution of sulfate groups.</p><p>The results presented in this thesis contribute to a greater understanding of the role of HS in angiogenesis and may provide valuable information for the development of cures against angiogenesis-related disorders.</p>

<p>Esophageal carcinoma is a malignancy with a poor prognosis and is the sixth cause of cancer related death worldwide. In Sweden approximately 400 new cases are diagnosed every year. The aim of this present thesis was to investigate predictive factors for esophageal carcinoma patients.126 esophageal carcinoma patients admitted to the department of Oncology at the University Hospital in Uppsala between 1990-2000 were investigated with focus on known and potential prognostic factors. Performance status and stage of the disease were the only independent prognostic factors (p-values <0.001). </p><p>Angiogenic factors VEGF and bFGF were correlated to platelet and leukocyte counts and VEGF was correlated to tumor volume (p=0.04) whereas bFGF was not (p=0.08) in pre-treatment serum samples from 42 esophageal carcinoma patients. The use of the angiogenic factors as prognostic factors, prior to therapy in patients with esophageal carcinoma, according to the results from the present study, seems limited. </p><p>HER-2 overexpression was seen in 17% of 97 investigated esophageal tumor samples. In squamous cell carcinoma patients, HER-2 overexpression correlated with poorer survival (p=0.035), whereas in adenocarcinoma patients, HER-2 status did not. HER-2 overexpression seems to be associated with poorer survival in esophageal carcinomas, especially in patients with squamous cell esophageal carcinoma. </p><p>Telomerase activity was detected in all esophageal cell lines, with a broad range of activity levels. No correlation was found between telomerase activity levels and sensitivity to investigated cytotoxic drugs. We therefore conclude that basal telomerase activity level is not a key determinant of sensitivity to standard cytotoxic drugs in esophageal carcinoma cell lines. </p><p>The virus HPV-16 was detected in 16 % of the patients; no other type HPV was detected. HPV-16 infection had no significant effect on survival (p=0.72). Our results did not show that HPV-16 increases survival or improve therapy response in patients with esophageal carcinoma.</p>

<p>The mechanisms behind many important aspects of blood- and lymphatic vessel formation have yet not been elucidated in detail. The primary objectives of this thesis have therefore been to study the effects of hypoxia, platelet-derived growth factor (PDGF) and vascular endothelial growth factors (VEGFs) on vascular development and function. </p><p>In conditions of low oxygen pressure, hypoxia, the survival of the organism is critically dependent on the ability to compensate for the reduced oxygen levels by promoting blood vessel growth and oxygen-independent energy production. Many direct effects of hypoxia in cells are attributed to the induction of a family of hypoxia-inducible transcription factors (HIFs) which control the expression of specific target genes. We found that capillary endothelial cells (ECs) respond to hypoxia with upregulation of genes involved in growth and remodeling of blood vessels. On the other hand, vein ECs responded to hypoxia with increased expression of genes involved in lymphatic vessel growth. Using differentiating embryonic stem (ES) cells, we have shown that hypoxia upregulates expression of VEGF receptor-3 (VEGFR-3) on blood vascular ECs. Furthermore, we have provided evidence for a critical role of VEGFR-3 in hypoxia-induced blood vessel development. </p><p>Activation of PDGF receptor-β (PDGFR-β) on early vascular progenitors in differentiating ES cells or in mice induces blood vessel differentiation, while negatively influencing early hematopoiesis. PDGFR-β expression on vascular progenitors may therefore play a role in guiding differentiation of the vascular lineages. </p><p>We have investigated the usefulness of differentiating ES cells as a model to study early lymphatic development. Administration of VEGF-C and VEGF-A induced formation of lymphatic vessel-like structures that seemed connected to the blood vasculature, supporting the general view that lymphatic ECs are derived from blood vascular ECs.</p><p>In summary, this thesis has provided new insights in the contribution of different growth factors in hematopoietic, blood- and lymphendothelial development. </p>

<p>During the past decade clinical islet transplantation has become a viable strategy for curing type 1 diabetes. The limited supply of organs, together with the requirement for islets from multiple donors to achieve insulin independence, has greatly limited the application of this approach. </p><p>The islets are infused into the liver via the portal vein, and once exposed to the blood, the grafted tissue has been shown to be damaged by the instant blood-mediated inflammatory reaction (IBMIR), which is characterized by coagulation and complement activation as well as leukocyte infiltration into the islets. Islet revascularization is a subsequent critical step for the long-term function of the transplanted graft, which may partially be impeded by the IBMIR. </p><p>In this thesis, we have explored novel strategies for circumventing the effects of the IBMIR and facilitating islet revascularization.</p><p>Systemic inhibitors of the IBMIR are typically associated with an increased risk of bleeding. We therefore evaluated alternative strategies for modulating the islets prior to transplantation. We demonstrated, using an adenoviral vector, that a high level of expression and secretion of the anticoagulant hirudin could be induced in human islets. An alternative approach to limiting the IBMIR was developed in which anticoagulant macromolecular heparin complexes were conjugated to the islet surface. This technique proved effective in limiting the IBMIR in both an in vitro blood loop model and an allogeneic porcine model of islet transplantation. An increased adhesion of endothelial cells to the heparin-coated islet surface was demonstrated, as was the capacity of the heparin conjugate to bind the angiogenic factors VEGF and FGF; these results have important implications for the revascularization process.</p><p>The outcome of the work in this thesis suggests that modulation of the islet surface is an attractive alternative to systemic therapy as a strategy for preventing the IBMIR. Moreover, the same techniques can be employed to induce revascularization and improve the engraftment of the transplanted islets. Ultimately, improved islet viability and engraftment will make islet transplantation a more effective procedure and increase the number of patients whose diabetes can be cured.</p>