Induction of apoptosis is the most studied cell death process and it is a tightly regulated physiological event that enables elimination of damaged and unwanted cells. Apoptosis can be induced via activation of either the intrinsic or the extrinsic signalling pathway. The intrinsic pathway involves activation of the mitochondria by stress stimuli, whereas the extrinsic pathway is triggered by ligand induced activation of death receptors such as Fas. Apoptosis induction via Fas activation plays an important role in the function of cytotoxic T lymphocytes and in the control of immune cell homeostasis. Several studies have shown that anticancer therapies require functional cell death signalling pathways. Irradiation based therapy has been successful in treatment of several malignancies but the usage of high doses has been associated with side effects. Therefore, low dose therapies, that either is optimized for specific delivery or administrated in combination with other treatments, are promising modalities. However, in order to achieve high-quality effects of such treatments, the death effector mechanisms involved in tumour eradication needs to be further explored. Importantly, tumour cells frequently acquire resistance to apoptosis, which consequently allows tumour cells to escape from elimination by the immune system and/or treatment. Interferons constitute a large family of pleotrophic cytokines that are important for the immune response against viruses and other microorganisms. The interferon signalling pathway mediates transcriptional regulation of hundreds of genes, which result in mRNA degradation, decreased protein synthesis, cell cycle inhibition and induction of apoptosis. Interferon has successfully been used in therapy against some tumours. However, several drawbacks have been reported, such as reduced sensitivity to interferon during treatment. The aim of this thesis was to elucidate mechanisms that mediate resistance to death receptor or interferon induced apoptosis in human tumour cell models, as well as investigate what molecular events that underlie cell death following radiation therapy of tumour cells. In order to elucidate mechanisms involved in acquired resistance to Fas- or interferon-induced apoptosis, a Fas- and interferon-sensitive human cell line, U937, was subjected to conditions where resistance to either Fas- or interferon induced apoptosis was acquired. Characterization of the Fas resistant cells showed that multiple resistant mechanisms had been acquired. Reduced Fas expression and increased cFLIP expression, which is an inhibitor of death receptor signalling, were two important changes found. To further examine the importance of these two alterations, clones from the Fas resistant population were established. The reduced Fas expression was determined to account for the resistant phenotype in approximately 70% of the clones. In the Fas resistant clones with normal Fas expression, the importance of an increased amount of the cFLIP protein was confirmed with shRNA interference. A cross-resistance to death receptor induced apoptosis was detected in the interferon resistant variant, which illustrates that a connection between death receptor and interferon induced apoptosis exists. Notably, interferon resistant cells also contained increased cFLIP expression, which were determined to mediate resistance to both interferon and death receptor mediated apoptosis. Finally, when cell death induced by irradiation treatment was investigated in HeLa Hep2 cells we could demonstrate that cell death was mediated by centrosome hyperamplification and mitotic aberrations, which forced the cells into mitotic catastrophes and delayed apoptosis. In conclusion, we have described model systems where selection for resistance to Fas or interferon induced apoptosis generated a heterogeneous population, where several signalling molecules were altered. Furthermore, we have shown that a complex cell death network was activated by irradiation based therapy.

Squamous cell carcinoma of the head and neck (SCCHN), the 6th most common cancer worldwide, has a low 5-year survival. Disease as well as treatment often causes patients severe functional and aesthetic problems. In order to improve treatment and diagnosis at earlier stages of tumour development it is important to learn more about the molecular mechanisms behind the disease. p63, an important regulator of epithelial formation, has been suggested to play a role in the development of SCCHN. Six different isoforms of p63 have been found and shown to have various functions. The aim of the studies in this thesis was to learn more about the role of p63 and proteins connected to p63 in SCCHN. Expression of p63, Cox-2, EGFR, beta-catenin, PP2A and p53 isoforms was mapped in tumours and normal tumour adjacent tissue from patients with SCCHN using western blot or RT-PCR. Results showed no significant difference between tumours and normal tumour adjacent tissue concerning expression of EGFR and beta-catenin. Cox-2 and PP2A showed significantly higher expression in tumours while p63 was more expressed in normal tumour adjacent tissue. However, expression of all these proteins in normal tumour adjacent tissue differed from tissue from disease-free non-smoking individuals. Smoking in itself did not affect expression of these proteins. The p53 isoforms p53, p53beta, p53gamma, ∆133p53, ∆133p53beta and ∆133p53gamma were expressed at RNA level in samples both from tumours and normal tumour adjacent tissue, though most of them at fairly low levels. The functional properties of the different p63 isoforms have not been fully mapped. By establishing stable cell lines over-expressing the different p63 isoforms we investigated their specific effect on tumour cells from SCCHN. Only the ∆Np63 isoforms could be stably over-expressed, whereas no clones over-expressing TAp63 could be established. Using microarray technique, cell lines stably expressing the ∆Np63 isoforms were studied and CD44, Keratins 4, 6, 14, 19 and Cox-2 were found to be regulated by p63. In conclusion, the present project adds new data to the field of p63 and SCCHN. For example, we have shown that clinically normal tumour adjacent tissue is altered compared to normal oral mucosa in non tumour patients, and that smoking does not change expression of p63, Cox-2, EGFR, beta-catenin or PP2A in oral mucosa. Novel p53 isoforms are expressed in SCCHN, and even though levels are very low they should not be overlooked. Furthermore, CD44, keratins 4, 6, 14, 19 and Cox-2 were identified as p63 targets in SCCHN.

Fibrosis is a sequel of chronic inflammation and is defined as an excessive deposition of collagen that ultimately leads to organ dysfunction. To date there are no effective treatments for fibrosis. The main cell type involved in collagen deposition and organization is the myofibroblast. In the first study we examined how myofibroblasts differentiate in human fibrotic conditions and in experimental animal models. Human tissues were stained with antibodies that recognize integrin receptors and in addition we also stained for α-SMA, a myofibroblast marker. We found a co-localization between these two markers in stromal cells and hypothesized that integrin α1 is important for the acquisition of the myofibroblast phenotype. To tests this hypothesis we used knockout animals for this integrin subunit. These animals showed a reduction of α-SMA positive fibroblasts, indicating that the α1 integrin subunit is required for proper myofibroblast differentiation. In the second study we used a neuroblastoma tumor model to study tumour growth when a drug targeting the synthesis of cellular NAD was administered. In treated animals an expansion of the nonvascular stroma was observed compared to controls. Normalization of the vasculature was observed in treated tumors together with a decrease in hypoxia. Moreover, this was followed by a decrease in stromal PDGF-B and VEGF expression, suggesting a deactivation of the stroma. In the third study the effects of over-expression of the two pro-fibrotic growth factors TGF-β and PDGF-B in skin was evaluated. We observed that both growth factors induced fibrosis. Over time, a decrease in blood vessel density was observed in both treatment groups. Both factors also stimulated an expansion of the connective tissue cell population originating from the microvascular pericyte, but the phenotype of these cells differed in the different treatments with regards to expression of markers. Furthermore, in tissue over-expressing PDGF-B but not TGF-β, the fibrotic process was partially reversible.

In addition to malignant cells, solid tumors comprise supporting stromal tissue that consists of extra cellular matrix (ECM), connective tissue cells, inflammatory cells and blood vessels. The stromal compartment and the malignant cells together shape the tumor microenvironment that in turn determines tumor progression and efficacy of anti-tumor treatments. In this thesis, studies that investigate the roles of different kinds of interactions between tumor cells and stromal cells were undertaken. Further, growth factors that have important roles in interactions between tumor cells and stromal cells were investigated in a non-tumor environment. Tumor cells were found to modulate the response to the platelet derived growth factor  (PDGF) by microvascular pericytes, a cell type found in the vasculature of solid tumors. The importance of this growth factor in biology of tumors has earlier been shown, but here it was shown that PDGF also modulate the ECM phenotype of solid tumors. The ECM of tumors treated with an inhibitor of PDGF receptor (PDGFR) signaling induced a less fibrotic collagen scaffold, which could explain how PDGFR inhibition in earlier reports lowered tumor interstitial fluid pressure (IFP). Lowering the normally high IFP in tumors increases efficacy of chemotherapy. The integrin αVβ3 is activated downstream of PDGF-B in acute inflammations, and this integrin is important for raising IFP in loose connective tissue in such conditions. However, in tumors we found that lack of the β3 subunit lead to an increased IFP, which were attributed to a more fibrotic ECM phenotype. In addition to PDGF-B, transforming growth factor β (TGFβ) is an important growth factor in the biology of tumors. These two growth factors were separately overexpressed in mouse skin and they both induced an inflammatory response. Expressed in a tumor free context, they evoked a response that was in many ways reminiscent of what can be observed in the tumor microenvironment. This thesis contributes further understanding of how the complex tumor microenvironment affects the phenotype of solid tumors.

Malignant glioma is a highly lethal and destructive disease with no proper cure. We have investigated some of the hallmarks of cancer in connection to glioma and found ways to disrupt these and prevent tumor growth. The work is done within the context of a glioma subtype distinguished by activation of PDGF signaling termed the proneural subtype. In two of the studies we have investigated mechanisms regulating the glioma cells themselves, and in the other two we have focused on the tumor stroma. In the first study, glioma-initiating cells were isolated in defined serum free culture medium from PDGF-B driven murine glioma and shown to be independent of EGF and FGF2 for self-renewal and proliferation. When cultured in serum the GICs displayed an aberrant differentiation pattern that was reversible. Specific depletion of the transduced PDGF-B caused a loss of self-renewal and tumorigenicity and induced oligodendrocyte differentiation. The transcription factor S-SOX5 has previously been shown to have a tumor suppressive effect on PDGF-B induced murine glioma, and to induce cellular senescence in PDGF-B stimulated cells in vitro. We found that S-SOX5 had a negative effect on proliferation of newly established human glioma cells cultured under stem cell conditions. We also revealed a connection between alterations causing up-regulation of SOX5 with the proneural subgroup and a tendency towards co-occurrence with PDGFRA alterations. Angiogenesis, the formation of new blood vessels from existing ones, is an important hallmark for glioma malignancy. We found that the anti-angiogenic protein HRG had a negative effect on glioma progression in PDGF-B induced experimental tumors and that HRG was able to completely prevent formation of glioblastomas. Subsequently it was shown that HRG could skew pro-tumorigenic tumor associated macrophages into an anti-tumorigenic phenotype. Stromal cells had not previously been fully investigated in gliomas. We observed a correlation between tumor malignancy and increased numbers of tumor-associated macrophages as well as pericytes in PDGF-B induced gliomas. There was also a correlation between tumor grade and vessel functionality that had not previously been shown. Our results offer further understanding of gliomagenesis and present possible future therapies.

<p>Understanding signalling pathways that control pancreatic endocrine tumour (PET) development and proliferation may reveal novel targets for therapeutic intervention. The pathogenesis for sporadic and hereditary PETs, apart from mutations of the <i>MEN1</i> and <i>VHL</i> tumour suppressor genes, is still elusive. The protein product of the <i>MEN1</i> gene, menin, regulates many genes. The aim of this thesis was to identify genes involved in pancreatic endocrine tumourigenesis, with special reference to Notch signalling.</p><p>Messenger RNA and protein expression of NOTCH1, HES1, HEY1, ASCL1, NEUROG3, NEUROD1, DLK1, POU3F4, PDX1, RPL10, DKK1 and TPH1 were studied in human PETs, sporadic and MEN 1, as well as in tumours from heterozygous <i>Men1</i> mice. For comparison, normal and <i>MEN1</i> non-tumourous human and mouse pancreatic specimens were used. Nuclear expression of HES1 was consistently absent in PETs. In mouse tumours this coincided with loss of menin expression, and there was a correlation between <i>Men1</i> expression and several Notch signalling factors. A new phenotype consisting of numerous menin-expressing endocrine cell clusters, smaller than islets, was found in <i>Men1</i> mice. Expression of NEUROG3 and NEUROD1 was predominantly localised to the cytoplasm in PETs and islets from MEN 1 patients and <i>Men1</i> mice, whereas expression was solely nuclear in wt mice. Differences in expression levels of Pou3f4, Rpl10 and Dlk1 between islets of <i>Men1</i> and wt mice were observed.</p><p>In addition, combined RNA interference and microarray expression analysis in the pancreatic endocrine cell line BON1 identified 158 target genes of ASCL1. For two of these, DKK1 (a negative regulator of the WNT/β-catenin signalling pathway) and TPH1, immunohistochemistry was performed on PETs. In concordance with the microarray finding, DKK1 expression showed an inverse relation to ASCL1 expression.</p><p>Altered subcellular localisation of HES1, NEUROD1 and NEUROG3 and down-regulation of DKK1 may contribute to tumourigenesis.</p>

<p>Varje år diagnostiseras över 50 000 individer med cancer i Sverige. Ett cancerbesked väcker blandade känslor och associeras ofta med lidande och död. Ett svårt besked kan leda till en förändrad livssituation och kan även ses som början på en lång och mödosam resa. En vetenskaplig litteraturstudie baserad på 15 originalartiklar genomfördes med syftet att belysa patientens upplevelse av ett cancerbesked och därmed öka sjuksköterskans förståelse för patientens situation samt fördjupa kunskaperna inom ämnet. Genom litteraturgranskningen identifierades tre teman: information, emotionella reaktioner samt psykosocialt stöd. Patienten upplever att det är viktigt att informationen ges på ett öppet och ärligt sätt. Vidare framkom det betydelsefullt att uppmärksamma patientens emotionella reaktioner i samband med beskedet. Eftersom upplevelsen av ett cancerbesked påverkar patientens fortsatta upplevelse av sin sjukdom, har sjuksköterskan en viktig roll att fylla genom att erbjuda psykosocialt stöd i de olika tänkbara situationer som kan uppkomma i samband med ett livsavgörande besked. Fortsatt forskning behövs för att jämföra hur de rekommendationer som finns angående delgivandet av ett svårt besked överensstämmer med patienternas egna upplevelser och önskemål.</p> / <p>Every year, over 50 000 individuals in Sweden are diagnosed with cancer. The disclosure of the cancer diagnosis arouses emotions and is often associated with suffering and death. Receiving bad news may lead to changes in life and can also be seen as the beginning of a long and difficult journey. A scientific study based on 15 original articles was carried out with the purpose to identify the patient’s experience of receiving a cancer diagnosis and therefore increase the nurse’s understanding for the patient’s situation and deepen the knowledge of the subject. When examining the articles three themes were identified: information, emotional reactions and psychosocial support. The patient experience that it is important that the information is given in an open and honest manner. Patients also find it important that their emotional reaction is being observed as receiving the diagnosis. As the disclosure of the cancer diagnosis affects the patient’s further perception of the disease the nurse has an important role providing psychosocial support in various situations that may arise in connection with the disclosure. Continued research is needed to compare how guidelines for giving bad news to a patient correspond with the patient’s own experiences and preferences.</p>

Understanding signalling pathways that control pancreatic endocrine tumour (PET) development and proliferation may reveal novel targets for therapeutic intervention. The pathogenesis for sporadic and hereditary PETs, apart from mutations of the MEN1 and VHL tumour suppressor genes, is still elusive. The protein product of the MEN1 gene, menin, regulates many genes. The aim of this thesis was to identify genes involved in pancreatic endocrine tumourigenesis, with special reference to Notch signalling. Messenger RNA and protein expression of NOTCH1, HES1, HEY1, ASCL1, NEUROG3, NEUROD1, DLK1, POU3F4, PDX1, RPL10, DKK1 and TPH1 were studied in human PETs, sporadic and MEN 1, as well as in tumours from heterozygous Men1 mice. For comparison, normal and MEN1 non-tumourous human and mouse pancreatic specimens were used. Nuclear expression of HES1 was consistently absent in PETs. In mouse tumours this coincided with loss of menin expression, and there was a correlation between Men1 expression and several Notch signalling factors. A new phenotype consisting of numerous menin-expressing endocrine cell clusters, smaller than islets, was found in Men1 mice. Expression of NEUROG3 and NEUROD1 was predominantly localised to the cytoplasm in PETs and islets from MEN 1 patients and Men1 mice, whereas expression was solely nuclear in wt mice. Differences in expression levels of Pou3f4, Rpl10 and Dlk1 between islets of Men1 and wt mice were observed. In addition, combined RNA interference and microarray expression analysis in the pancreatic endocrine cell line BON1 identified 158 target genes of ASCL1. For two of these, DKK1 (a negative regulator of the WNT/β-catenin signalling pathway) and TPH1, immunohistochemistry was performed on PETs. In concordance with the microarray finding, DKK1 expression showed an inverse relation to ASCL1 expression. Altered subcellular localisation of HES1, NEUROD1 and NEUROG3 and down-regulation of DKK1 may contribute to tumourigenesis.

The incidence of cutaneous malignant melanoma has increased dramatically in Caucasians the last few decades, an increase that is partly explained by altered sun exposure habits. For the individual patient, with a localized disease, the tumor thickness of the excised lesion is the most important prognostic factor. However, there is a need to identify characteristics that can place patients in certain risk groups. In this study, the protein expression of multiple proteins in malignant melanoma tumors was studied, with the aim of identifying potential new candidate biomarkers. Representative samples from melanoma tissues were assembled in a tissue microarray format and protein expression was detected using immunohistochemistry. Multiple cohorts were used and for a subset of proteins the expression was also analyzed in melanocytes in normal skin and in benign nevi. The immunohistochemical staining was evaluated manually and for part of the proteins also with an automated algorithm. The protein expression of STX7 was described for the first time in tumors of the melanocytic lineage. Stronger expression of STX7 and SOX10 was seen in superficial spreading melanomas compared with nodular malignant melanomas. An inverse relationship between STX7 expression and T-stage was seen and between SOX10 expression and T-stage and Ki-67, respectively. In a population-based cohort the expression of MITF was analyzed and found to be associated with prognosis. Twenty-one potential biomarkers were analyzed using bioinformatics tools and a protein signature was identified which had a prognostic value independent of T-stage. The protein driving this signature was RBM3, a protein not previously described in malignant melanoma. Other markers included in the signature were MITF, SOX10 and Ki-67. In conclusion, the protein expression of numerous potential biomarkers was extensively studied and a new prognostic protein panel was identified which can be of value for risk stratification.

Background Colorectal cancer (CRC) is the second most common malignancy in developed countries. The mortality is high, with nearly half of patients dying from the disease. The primary treatment of CRC is surgery, and decisions about additional treatment with chemotherapy are based mainly on tumor stage. Novel prognostic markers that identify patients at high risk of recurrence and cancer-related death are needed. The development of CRC has been described in terms of two different pathways; the microsatellite instability (MSI) and chromosomal instability (microsatellite stable, MSS) pathway. More recently, the CpG island methylator phenotype (CIMP), characterized by frequent DNA hypermethylation, has been described as an alternative pathway of tumorigenesis. The event of DNA methylation is dependent on one-carbon metabolism, in which folate and vitamin B12 have essential functions. The purpose of this thesis was to study CIMP in CRC. The specific aims were to investigate the potential role of components of one-carbon metabolism as risk factors for this subgroup of tumors, and the prognostic importance of CIMP status, taking into consideration important confounding factors, such as MSI and tumor-infiltrating T cells. Methods CRC cases and referents included in the Northern Sweden Health and Disease Study (NSHDS, 226 cases and 437 referents) and CRC cases in the Colorectal Cancer in Umeå Study (CRUMS, n=490) were studied. Prediagnostic plasma concentrations of folate and vitamin B12 were analyzed in NSHDS. In both study groups, CIMP status was determined in archival tumor tissue by real-time quantitative PCR using an eight-gene panel (CDKN2A, MLH1, CACNA1G, NEUROG1, RUNX3, SOCS1, IGF2 and CRABP1). MSI screening status and the density of tumor-infiltrating T cells were determined by immunohistochemistry.  Results An inverse association was found between plasma concentrations of vitamin B12 and rectal, but not colon, cancer risk. We also found a reduced risk of CIMP-high and CIMP-low CRC in study subjects with the lowest levels of plasma folate. We found that patients with CIMP-low tumors in both NSHDS and CRUMS had a poorer prognosis compared with CIMP-negative, regardless of MSI screening status. We also found that MSS CIMP-high patients had a poorer prognosis compared with MSS CIMP-negative. The density of tumor-infiltrating T cells and CIMP status were both found to be independent predictors of CRC patient prognosis. A particularly poor prognosis was found in patients with CIMP-low tumors poorly infiltrated by T cells. In addition, the density of T cells appeared to be more important than MSI screening status for predicting CRC patient prognosis. Conclusion Rather than being one disease, CRC is a heterogeneous set of diseases with respect to clinico-pathological and molecular characteristics. We found that the association between risk and plasma concentration of vitamin B12 and folate depends on tumor site and CIMP status, respectively. Patient prognosis was found to be different depending on CIMP and MSI screening status, and the density of tumor-infiltrating T cells.