| 1. |
- Andersson, Britta, 1979-
(författare)
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Manipulation of potassium ion fluxes to induce apoptosis in lung cancer cells
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Apoptosis is a special form of cell death that if non-functional may lead to diseases such as cancer. A reduction of the intracellular potassium ion (K+) content is necessary for activating enzymes important for the execution of apoptosis. Pharmacological modulation of K+ fluxes to reduce intracellular K+ in cancer cells might therefore force the cells into apoptosis and decrease tumour cell mass. Human malignant pleural mesothelioma (MPM) is a form of cancer often caused by asbestos exposure. Although asbestos has been banned in the Western World, the incidence of MPM is expected to increase. Cisplatin is the first-line chemotherapy for MPM, but acquired resistance to the drug is a clinical problem. This thesis is mainly based on work with the human malignant pleural mesothelioma cell line (P31 wt) and a cisplatin-resistant sub-line (P31 res). The aim was to first characterize K+ fluxes in P31 wt and P31 res cells, and then manipulate them in order to reduce intracellular K+ and induce apoptosis with K+ manipulation alone or in combination with cisplatin. Characterization of K+ fluxes in P31 wt cells showed that: 1) ouabain, a digitalis-like drug, and specific blocker of the Na+, K+, ATPase pump, effectively inhibited K+ uptake, 2) bumetanide, a diuretic, and an inhibitor of the Na+, K+, 2Cl-¬-cotransporter, had a transient effect on K+ uptake, and 3) the antifungal drug amphotericin B stimulated K+ efflux. In order to determine intracellular K+ content, the potassium-binding fluorescent probe PBFI-AM was used in a 96-well plate assay. After a 3-h incubation with ouabain, with or without bumetanide, combined with amphotericin B, the intracellular K+ content was reduced in P31 wt cells but not in P31 res cells. Ouabain induced apoptosis in both P31 wt and P31 res cells. P31 res cells were sensitized to cisplatin by ouabain, since 10 mg/L cisplatin in combination with ouabain induced about the same percentage of apoptotic cells as 40 mg/L cisplatin. Apoptosis was executed via caspase-3 activation in both P31 wt and P31 res cells. Amphotericin B enhanced ouabain-induced apoptosis in P31 wt cells via caspase-9 activation, with increased caspase-3 activation and DNA fragmentation as consequences. Ouabain-induced apoptosis in P31 res cells was executed via increased expression of pro-apoptotic Bak. The combination of cisplatin with ouabain and amphotericin B was stressful to both P31 wt and P31 res cells, since SAPK/JNK a known factor in stress-induced apoptosis was activated. In conclusion, K+ flux manipulation with clinical used drugs can induce apoptosis per se and also enhance cisplatin-induced apoptosis in P31 wt and P31 res cells.
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| 2. |
- Faraz, Mahmood, 1978-
(författare)
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Investigations of Leucine-rich repeats and immunoglobulin-like domain-proteins 1 and 2 (LRIG1 and LRIG2) and their genes in cancer
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The mammalian leucine-rich repeats and immunoglobulin-like domains (LRIG) gene family consists of three different members, LRIG1, LRIG2, and LRIG3. These genes are expressed in all human and mouse tissues analyzed to date. All LRIG proteins share similar and evolutionary conserved structural domains including a leucine-rich repeat domain, three immunoglobulin-like domains, a transmembrane domain, and a cytosolic tail. Since the discovery of this family, around 20 years ago, various research groups have shown the importance of this family in cancer biology and prognosis. The aim of this thesis was to further investigate the role of LRIG1 and LRIG2 in cancer.To investigate the roles of LRIG1 and LRIG2 in physiology and gliomagenesis, we generated Lrig1- and Lrig2-deficient mice and induced platelet-derived growth factor B (PDGFB)-driven gliomagenesis. We studied the effects of Lrig2 ablation on mouse development and survival and investigated if the ablation of Lrig1 or Lrig2 affects the incidence or malignancy of induced gliomas. We also investigated if Lrig2 ablation affects Pdgfr signaling in mouse embryonic fibroblasts (MEFs). Additionally, we analyzed the effects of ectopic LRIG1 expression in human primary glioblastoma cell lines TB101 and TB107, in vivo and in vitro. We reported no macroscopic anatomical defect but reduced growth and increased spontaneous mortality rate in Lrig2-deficient mice. However, the Lrig2-deficient mice were protected against the induced gliomagenesis. Lrig2-deficient MEFs showed faster kinetics of induction of immediate-early genes in response to PDGFB stimulation, whereas the phosphorylations of Pdgfra, Pdgfrb, Erk1/2, and Akt1 appeared unaltered. Lrig1-heterozygote mice showed a higher incidence of high-grade tumors (grade IV) compared to wildtype mice, demonstrating a haploinsufficient function of Lrig1. LRIG1 overexpression suppressed TB107 cell invasion in vivo and in vitro, which was partially mediated through the suppression of the MET receptor tyrosine kinase.To identify LRIG1-interacting proteins, we used the yeast-two hybrid system and data-mined the Bio-Plex network of high throughput protein-protein interaction database. To study the function of interactors, we used a triple co-transfection system to overexpress LRIG1 and PDGFRA and downregulate endogenous levels of interactors by short hairpin RNAs (shRNAs), simultaneously. This analysis demonstrated that CNPY3, CNPY4, GAL3ST1, GML, HLA-DRA, LRIG2, LRIG3, LRRC40, PON2, RAB4A, and ZBTB16 were important for the PDGFRA-downregulating function of LRIG1.To investigate the clinical significance of LRIG1 copy number alterations (CNAs) in breast cancer, we used droplet digital PCR (ddPCR) to analyze 423 breast cancer tumors. We found that LRIG1 CNAs were significantly different in steroid-receptor-positive vs steroid-receptor-negative tumors and in ERBB2-amplified vs ERBB2-non-amplified tumors. In the whole cohort, patients with LRIG1 loss or gain had a worse metastasis-free survival than patients with normal LRIG1 copy numbers, however, among the early-stage breast cancer subgroup, this difference was not significant. In summary, Lrig1 behaved like a haploinsufficient tumor suppressor gene in malignant glioma, whereas Lrig2 appeared to promote malignant glioma. Our functional analysis of LRIG1 interactome uncovered several unanticipated and novel proteins that might be important for the regulation of receptor tyrosine kinases by LRIG1. LRIG1 CNAs predicted metastasis-free survival time in breast cancer. Hopefully, our findings might lead to a better understanding of the regulation of growth factor signaling and its importance in cancer biology and prognosis.
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| 3. |
- Holmlund, Camilla, 1969-
(författare)
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Identification and investigations of leucine-rich repeats and immunoglobulin-like domains protein 2 (LRIG2)
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Receptor tyrosine kinases (RTKs) constitute a family of proteins controlling cell growth and proliferation and whose activities are tightly controlled in normal cells. LRIG1 is a negative regulator of RTK signaling and is a proposed tumor suppressor. The aim of this thesis was to identify and study possible paralogs of LRIG1. By using the basic local alignment search tool and cDNA cloning, a human mRNA sequence with similarity to LRIG1 was identified and named LRIG2. By fluorescence in situ hybridization analysis, LRIG2 was found to reside on chromosome 1p13. The LRIG2 amino acid sequence was 47% identical to LRIG1, and the predicted protein domain organization was the same as that of LRIG1. Antibodies against LRIG2 were developed and the apparent molecular weight of the protein was determined to be 132 kDa by SDS-polyacrylamide gel electrophoresis and Western blot analysis. The sub-cellular localization was studied by cell surface biotinylation experiments and confocal fluorescence laser microscopy, which revealed that LRIG2 resided at the cell surface and in the cytoplasm. The expression patterns of LRIG2 mRNA, during development and in adult tissues, were evaluated using whole-mount in situ hybridization and quantitative real-time RT-PCR, respectively. In E10.5, E11.5 and E12.5 mouse embryos, the Lrig2 expression domains were both overlapping and unique as compared to the expression domains of Lrig1 and the third family member, Lrig3. In adult human tissues, the most prominent LRIG2 mRNA expression was found in skin, uterus and ovary. To study the developmental and physiological role of LRIG2, Lrig2 knock-out mice were generated. The knock-out mice were born at Mendelian frequencies without any apparent morphological abnormalities. However, Lrig2 knock-out mice showed reduced body weight between 5 days and 12-15 weeks of age, increased mortality, and impaired reproductive capacity. To study the role of LRIG2 as a prognostic factor in oligodendroglioma, LRIG2 expression was analyzed in 65 human oligodendrogliomas by immunohistochemistry. Cytoplasmic LRIG2 expression was an independent prognostic factor associated with poor oligodendroglioma patient survival. The possible functional role of LRIG2 in oligodendroglioma biology was further investigated using the RCAS/tv-a mouse model. Tumors resembling human oligodendroglioma were induced by intracranial injection of PDGFB carrying RCAS retroviruses into newborn Ntv-a mice. Lrig2 wild-type animals developed tumors at a higher frequency and of higher malignancy than the Lrig2 knock-out mice. This result supports the notion that LRIG2 promotes PDGF-induced oligodendroglioma genesis. A possible molecular mechanism was revealed as LRIG2 overexpression increased PDGFRa levels in transfected cells. In summary, we identified a new gene named LRIG2, showed that it is expressed in a variety of tissues during development and in adulthood, knocked it out and found that it was required for proper animal growth, health, and reproduction. We also found that Lrig2 expression promoted PDGF-induced oligodendroglioma genesis and was associated with poor oligodendroglioma patient survival, possibly via a PDGFRa stabilizing function.
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| 4. |
- Janson, Veronica, 1974-
(författare)
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Cisplatin-resistance and cell death in malignant pleural mesothelioma cells
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Malignant pleural mesothelioma (MPM) is an aggressive, treatment-resistant tumour. Cisplatin (cis-diamminedichloroplatinum (II)) is the best single-agent chemotherapy for MPM, but platinum-based combination therapies give the best overall response rates. However, cisplatin use is limited by resistance and severe side effects. This thesis has increased the knowledge concerning cisplatin-induced cell death in MPM by describing a novel potential therapeutic target, and three novel phenotypes of cisplatin-resistance in a human MPM cell line (P31) and its cisplatin-resistant sub-line (P31res1.2). The novel potential therapeutic target, and one of the novel phenotypes, was cisplatin-resistant pro-apoptotic BH3-only proteins. In the P31 cells, cisplatin transiently increased pro-apoptotic BH3-only proteins during 6 h of exposure. This response was almost completely abrogated in the P31res1.2 cells. De-regulated caspase activity and activation was the second novel phenotype identified. The P31res1.2 cells had earlier, possibly mitochondria-independent, caspase-3 activation, increased basal caspase-3 activity and increased basal cleavage of caspase-8 and -9. Despite these differences, 6-h equitoxic cisplatin exposures rendered 50-60% of the cells apoptotic in both cell lines. The third novel phenotype was abrogated Na+K+2Cl--cotransporter (NKCC1) activity. Although NKCC1 activity was dispensable for cisplatin-induced apoptosis, balanced potassium transport activity was essential for P31 cell survival. Finally, the survival signalling protein Protein Kinase B (PKB or Akt) isoforms α and γ were constitutively activated in a PI3K-independent manner in P31 cells. In the P31res1.2 cells, PKBα and γ activities were increased, and there was PI3K-dependent activation of PKBβ. However, this increase in PKB isoform activity was not strongly associated to the cisplatin-resistance of the P31res1.2 cells.
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| 5. |
- Johansson, David, 1979-
(författare)
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Bacterial toxins for cancer treatment
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Even though anti‐cancer chemotherapy has been continuously improved during the last decades. problems with adverse effects and drug resistance still constitutes a considerable obstacle and sets a demand for new effective treatment options. Tissue homeostasis in multi‐cellular organisms is maintained through intrinsic cell death, apoptosis, which removes unwanted or damaged cells. Disrupted apoptosis is an important factor in tumorgenesis and drug resistance, therefore induction or restoration of apoptotic pathways is also important for the treatment of cancer. Several naturally occurring bacterial toxins have the ability to induce apoptosis and could thus be candidates to complement or improve the therapeutic effect of other anticancer drugs. The bacterial toxins, adenylate cyclase (AC) toxin from Bordetella pertussis, α‐toxin from Staphylococcus aureus and verotoxin‐1 (VT‐1) from Escherichia coli were investigated for their ability to induce apoptosis in different tumor cell lines. Toxin induction of cell death was investigated by cell viability assays, end‐stage apoptosis induction by DNA‐fregmentation (TUNEL) assay. Toxin receptor expression and signal transduction pathways to apoptosis were investigated by flow cytometry, caspase enzyme activity assays and western blot. Immunohistochemistry was used for identification of toxin receptor expression in tumor tissue samples. AC‐toxin was cytotoxic and induced apoptosis in cultured malignant plural mesothelioma (MPM) and small‐cell lung cancer (SCLC) cells. Low‐toxic concentrations of AC‐toxin enhanced cisplatin cytotoxicity and apoptosis in both cell lines. MPM‐cells with acquired cisplatin resistance were more sensitive to α‐toxin than the less resistant parental MPM cell line. A low‐toxic concentration of α‐toxin re‐sensitized resistant MPM cells to cisplatin cytotoxicity by apoptosis induced through the mitochondrial pathway without detectable activation of common up‐stream apoptosis signalling proteins. VT‐1 was highly cytotoxic and induced apoptosis in globotriosylceramide (Gb3) ‐expressing glioma, breast cancer and non‐small‐cell lung cancer (NSCLC) cells but was not cytotoxic to non‐Gb3‐expressing cells. PPMP, an inhibitor of glucosylceramide synthesis which makes exposed cells unable to synthesize Gb3 rendered Gb3‐expressing cells resistant to VT‐1. MPM cells with acquired‐cisplatin resistance expressed Gb3 in contrast to the absent of expression in the less resistant parental cell line. Gb3, could however be up‐regulated by cisplatin in Gb3‐negative MPM‐cells. Presence of a low‐toxic concentration of VT‐1 potentiated cisplatin‐induced cytotoxicity and apoptosis in the cisplatin‐resistance MPM cell line. VT‐1 was a potent inducer of apoptosis, probably via stress‐induced Mitogen‐activated protein kinase (MAPK)‐signaling involving c‐Jun N‐terminal kinase (JNK) and p38, leading to disruption of the mitochondrial membrane integrety, activation of caspase‐9 and ‐3, and ultimately DNA fragmentation and cell death. Gb3 expression was demonstrated in clinical specimens of glioblastoma and breast cancer making these tumor types interesting for further VT‐1 studies. We conclude that bacterial toxins may be used to induce apoptosis in several types of cancer cells. Low concentrations of verotoxin‐1 and α‐toxin may potentially be used to overcome acquired cisplatin‐resistance in cancer patients.
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| 6. |
- Karlsson, Terese, 1979-
(författare)
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The expression and molecular functions of LRIG proteins in cancer and psoriasis
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The leucine-rich repeats and immunoglobulin-like domains (LRIG) family consists of three integral membrane proteins that are important in human cancer. LRIG1 is a negative regulator of growth factor signaling. Its expression is associated with longer survival in several cancer types, and the gene has been shown to function as a tumor suppressor. The roles of LRIG2 and LRIG3 are less well known. The aim of this thesis was to improve our understanding of the expression and function of the LRIG protein family in psoriasis and cancer.To investigate their expression in psoriasis, the mRNA levels and subcellular localization of the LRIG proteins were analyzed and compared between normal and psoriatic human skin. There were no differences in the LRIG mRNA levels between psoriatic and normal skin samples. However, the subcellular localization of all three LRIG proteins differed between psoriatic and normal skin.To study the physiological and molecular functions of Lrig2, we generated Lrig2E12-/- mice. These mice were viable and born at a Mendelian rate, but Lrig2E12-/- mice had an increased rate of spontaneous mortality and a transient reduction in growth rate compared to Lrig2 wild-type (wt) mice. In an orthotopic platelet-derived growth factor (PDGF)B-driven brain tumor mouse model, we studied the effect of Lrig2 on gliomagenesis. All Lrig2 wt mice developed tumors; 82% developed grade II/III tumors, and 18% developed grade IV tumors. Only 77% of the Lrig2E12-/- mice developed tumors, and they were all grade II/III tumors. Thus, Lrig2 increased the incidence and malignancy rates of PDGFB-driven gliomas. We then analyzed the effect of Lrig2 on Pdgf receptor (Pdgfr) signaling. Lrig2 had no effect on Pdgfr steady-state levels, the starvation-induced up-regulation of Pdgfrs, the phosphorylation of Pdgfrs, primary cilium formation or the PDGFBB-induced phosphorylation of Akt or Erk1/2. However, the kinetics of induction of the immediate-early genes Fos and Egr2 were altered, resulting in a more rapid induction in Lrig2E12-/- cells.We then analyzed the clinical and biological importance of LRIG1 in lung cancer. In a human lung cancer tissue micro-array (TMA), LRIG1 expression was found to be an independent positive prognostic factor for adenocarcinoma. To study the importance of Lrig1 regarding lung cancer development in vivo, we used an inducible EGFRL858R-driven mouse lung cancer model. The mice developed diffuse lung adenocarcinoma, and the tumor burden was greater in Lrig1-/- mice than in Lrig1+/+ mice (p = 0.025) at 60 days. The human lung cancer cell line H1975, with either normal or Tet-induced expression of LRIG1, was injected into the flanks of Balb/cA nude mice. Tumors formed by LRIG1-overexpressing cells were smaller than those formed by parental cells, further indicating that LRIG1 is important during lung tumor formation or growth. In vitro, LRIG1 suppressed the proliferation of H1975 cells and down-regulated the phosphorylation of MET and RET.To investigate the molecular functions of LRIG proteins further, we performed a yeast two-hybrid (YTH) screen using a peptide from the cytosolic tail of LRIG3 as bait. This screen identified LMO7 and LIMCH1 as prominent interaction partners for LRIG3. Proximity ligation assays showed that LMO7 interacted with all of the LRIG proteins at endogenous expression levels. LMO7 and LIMCH1 were expressed in all human tissues analyzed. Their expression was dramatically decreased in lung cancer compared to normal lung tissue. The expression of LMO7 was analyzed in a human lung cancer TMA. LMO7 was expressed in respiratory epithelial cells in normal lungs. However, LMO7 was only expressed in a quarter of the lung tumors. LMO7 expression was found to be an independent negative prognostic factor for lung cancer.In summary, we found that the LRIG proteins were redistributed in psoriatic skin. In a mouse glioma model, Lrig2 promoted oligodendroglioma genesis. LRIG1 was an independent positive prognostic factor in human lung cancer. Lrig1 ablation increased the tumor size in an EGFRL858R-driven lung cancer mouse model. LRIG1 expression decreased the tumor growth of human lung cancer cells in a xenograft mouse model. LMO7 interacted with all three LRIG proteins and was an independent negative prognostic factor in human lung cancer. These data demonstrate the importance of LRIG proteins in human disease.
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| 7. |
- Kero, Martin
(författare)
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Garbage collection for reactive real-time systems
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Predictable use of resources, such as processor time and memory, is a desirable property for virtually any computer system. In real-time computing, static predictability is of particular concern. A real-time system typically maintains an ongoing interaction with its environment, concurrently executing tasks at predefined intervals or as responses to sporadic external events. Its purpose is often safety-critical, where failures to meet deadlines may have severe consequences - even loss of life. The substantial body of research in real-time scheduling theory has demonstrated that a priori guarantees on schedulability are achievable. What is needed is some carefully chosen restrictions on how tasks may interact and what timing behavior external events may exhibit. Safe use of shared resources in real-time systems are enabled by protocols for preserving mutually exclusive access to critical sections, free of deadlocks and priority inversions. The ability to achieve a priori schedulability guarantees can be preserved by taking the imposed restrictions into account. Nonetheless, allowing real-time tasks to share heap allocated data has far more complex consequences than just being a schedulability issue concerning shared resources. In order to guarantee failure free operation, the system must be free of memory related errors, such as memory leaks and dangling pointers. It is well-known that garbage collection can solve these problems. However, incorporating a garbage collector in a real-time system imposes a set of other requirements related to schedulability. This includes provably safe upper-bounds on required execution time and memory of the garbage collector in the presence of concurrently executing tasks, as well as preserved ability to achieve static schedulability guarantees of the real-time tasks. The body of research work towards establishing a priori schedulability guarantees of garbage collected real-time systems has been growing for the past decade. However, most of the existing work lacks a clear identification of the parameters required for and their impact on establishing a provably safe upper-bound on garbage collection execution time. The lack thereof has often imposed overly simplistic models for the cost of garbage collection; and - probably even more alarming - tractability of finding safe bounds of the involved parameters has not been established. Furthermore, most existing approaches require specialized scheduling policies and schedulability tests, as well as intrusive restrictions on the task model.In this dissertation, we propose the following theses: (1) the key to successful realtime garbage collection is to preserve as much as possible of previous advances in realtime scheduling theory by imposing minimal restrictions on the task model, scheduler, and schedulability test; and (2) the keys to enabling a priori schedulability guarantees are clear identification and tractable analysis of the sources of execution time for the garbage collector. Proofs of our theses are based on the run-time behavior of the real-time programming language Timber and an incremental copying garbage collector running as the lowest priority (idle) process.We identify all parameters needed for establishing a safe and tight upper bound on execution time of our collector, where the major ones (not surprisingly for a copying collector) are related to the amount of live heap space. We present a novel technique for establishing safe upper bounds of live heap space parameters for real-time systems. We rely on existing techniques for finding safe upper-bounds of parameters related to heap allocation of each task. Finally, we present the garbage collection demand analysis, decoupled from the schedulability analysis used for the real-time tasks, which determines if our collector is schedulable in the system.
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| 8. |
- Lindström, Annika, 1953-
(författare)
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Prognostic factors for squamous cell cervical cancer : tumor markers, hormones, smoking, and S-phase fraction
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Cervical cancer is the second most common malignancy in women worldwide and one of the leading causes of cancer mortality globally. In patients with invasive cervical cancer prognostic factors are of value for the choice of treatment, monitoring of treatment and follow-up. The most important clinical prognostic factors are stage, tumor volume, parametrial infiltration, vascular invasion, lymph node metastases, and distant metastases. An improved estimation of the prognosis of cervical cancer is desirable, especially in early cancer stages.The aim of this research was to study possible associations between tumor markers, female sex steroids, smoking, S-phase fraction (SPF), and prognosis in invasive squamous cell cervical cancer (SCC). The study comprised 190 patients with SCC, stages IB-IV, admitted to the Department of Gynecologic Oncology at Norrland University Hospital in Umeå between September 1984 and October1990. Ten year mortality was estimated.In study I, of a total of 103 patients, it was found that increased tumor growth, measured by the DNA SPF, was associated with elevated serum progesterone and smoking in the premenopasual patients and with aneuploidy in the whole group.In study II, comprising 128 patients, survival length related to hormone levels and SPF was evaluated in women who died of cervical cancer. In both pre- and postmenopausal women, who died of cervical cancer, SPF at or above 12% was correlated with reduced survival. There was significant positive correlation between a low serum estradiol/progesterone ratio and short survival in those premenopausal women who died of cancer (p=0.02).In study III, ten-year follow-up results in 128 women were compared with the expression of ten relevant tumor markers, assessed by immunohistochemistry. The overall ten-year survival rate in patients with low COX-2 and high CD4+ expression was 76%, versus 53% in the remaining women. The survival rate with absent p53 and high COX-2 expression in the tumors was 42%, versus 71%, while the corresponding figure for the combination of high COX-2 intensity and expression of c-myc was 27%, versus 62%. None of the single markers correlated significantly with outcome in the final Cox regression analyses, while five combinations did.Study IV addressed possible associations between selected tumor markers and cofactors in SCC. Ten tumor markers were examined in 128 patients. Smoking habits and previous oral contraceptive use were recorded. Serum estradiol and progesterone levels were evaluated in 80 women. Highly significant associations were found between strong c-myc staining and increased progesterone, low EGFR staining and high serum estradiol, and absence of p53 staining and smoking. There was an association between absence of p53 and high serum progesterone.In study V, LRIG1 expression was studied in 128 patients and was compared with expression of nine other tumor markers, smoking history, hormone levels, and prognosis. LRIG1 appears to be a significant prognostic predictor in early stage SCC, independent of the other tumor markers that were studied. Diminished expression in advanced cancer stages and the inverse correlation to serum progesterone and smoking indicate that LRIG1 is a tumor suppressor in squamous cell cervical cancer.Conclusion: The results of these studies support a role of progesterone as a promoter of cervical cancer and indicate that smoking is associated with tumor progression. A combination of tumor markers might be of help in prognostic prediction. LRIG1 acts as a tumor suppressor. These findings might contribute towards greater understanding of prognostic prediction of squamous cell cervical cancer.
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| 9. |
- Ljuslinder, Ingrid, 1968-
(författare)
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Studies of LRIG1 and the ERBB receptor family in breast and colorectal cancer
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The LRIG1 gene (leucine-rich repeats and immunoglobulin like domains-1) at chromosome 3p14 is a proposed tumour suppressor gene whose gene product negatively regulates various receptor tyrosine kinases. This function has been the basis for classifying LRIG1 as a potential tumour suppressor gene (TSG). The ERBB receptor family is important in malignant cellular functions such as proliferation, survival, adhesion, migration and differentiation. In breast cancer, amplification of the ERBB2 proto-oncogene is an important negative prognostic factor. The epidermal growth factor receptor (EGFR/ERBB1), is expressed in colorectal cancer and has been correlated to a worse prognosis. Until recently, immunohistochemical analysis of EGFR expression was used to select patients suitable for treatment with EGFR targeted antibodies. This thesis characterizes LRIG1 in breast and colorectal cancer to gain further knowledge of the gene and its expression. Also, the EGFR expression in metastases and the invasive margin of colorectal cancers was investigated to correlate changes to clinical factors. Breast cancer samples and matched normal tissues were evaluated for LRIG1 and the ERBB receptors at gene, RNA and protein levels. An increase in copy number of the LRIG1 gene was evident. Also, increased LRIG1 copy number was associated with high levels of ERBB2 mRNA. Another set of breast cancer tumours were analysed for LRIG1 by FISH analysis. The results were coherent with the previous results. To further analyze the correlation to ERBB2, tumours with LRIG1 increased copy number were analysed for ERBB2. The data showed that 89% of tumours with increased LRIG1 copy number were either ERBB2 amplified or had an increased copy number of ERBB2. To investigate LRIG1 and the EGFR in colorectal cancer, the gene and protein expression was analysed by several methods in tumours and corresponding normal tissues. There were no significant changes at gene level found, but at the protein level, both over- and under expression were seen. No evident correlation between LRIG1 and EGFR expression was detected. The ERBB receptor family expression in colorectal cancer tumours and corresponding metastases was investigated to explore if the expression was altered in the metastatic lesion. The results showed that the EGFR expression was lost in the corresponding metastases in 33% of the tumours and that the same percentage of tumours gained expression in the metastases. Co-expression of the ERBB family members was also analysed; there was a significant increase of ERBB3/ERBB4 co-expression in late stage tumours. EGFR expression at the invasive margin of colorectal cancers was analysed to clarify whether expression correlated to the patient’s prognosis. Significant correlation to survival and the presence of budding was seen. In conclusion, 34% of the breast cancer tumours studied had an increased copy number of LRIG1 with a significant co-incidental increase in ERBB2 copy number. This raises the question of a functional correlation between LRIG1 and ERBB2, a finding that might be of clinical importance. The studies of EGFR and the ERBB receptors in colorectal cancer reflect the heterogeneity of EGFR expression in tumours. In addition, these findings suggest that survival of the patients correlates to an increasing EGFR expression at the invasive margin.
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| 10. |
- Malmström, Annika, 1957-
(författare)
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Studies for Better Treatment of Patients with Glioma
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In Sweden annually over 500 people will be diagnosed with the malignant brain tumor glioma. They are graded from I-IV. The majority are glioblastoma (grade IV) (GBM), these being the most aggressive type. Median survival for those treated with standard of care is expected to be around 15 months. This tumor will mainly affect those 60 years or older.The studies in this thesis focus on treatment of patients with malignant gliomas grade III and IV. The aim of the studies is to improve the care of glioma patients. Papers I and II explored different therapeutic options in randomized trials, to facilitate individualized treatment recommendations. Findings from studies I and II, together with additional trials, demonstrated the importance of analyzing the tumor marker O6-methylguanine DNA methyltransferase (MGMT) methylation status for survival of GBM patients treated with Temozolomide (TMZ). The third paper investigated how the analysis of this marker is implemented internationally.The first study (paper I, Nordic trial) investigated treatment options for patients 60 years or older with GBM. The trial compared standard radiotherapy (SRT) over 6 weeks versus hypofractionated radiotherapy (HRT) over 2 weeks versus single agent TMZ administered in up to six 4 weekly cycles. In all, 342 patients were included in the trial. This study demonstrated that those randomized to TMZ had superior survival as compared to SRT. In addition, quality of life (QoL) data also suggested a better QoL for TMZ treatment than for radiotherapy. The benefit of TMZ treatment seemed to be limited to those with the tumor molecular marker MGMT methylated (inactivated).The second trial (paper II, Neoadjuvant trial) studied whether integrating TMZ treatment with SRT for patients younger than 60 years with GBM (grade IV) and astrocytoma grade III would confer a survival benefit, if administered postoperatively, before the start of SRT (neoadjuvant). TMZ was provided for 2-3 four weekly cycles followed by SRT to patients randomized to neoadjuvant treatment and was compared to postoperative SRT alone. Although this trial could not illustrate any advantage of delaying the start of SRT while administering TMZ for the study cohort in general, for those included as astrocytoma grade III the median survival was found to be superior by 5 years when randomized to neoadjuvant TMZ. This trial also confirmed the importance of MGMT promoter methylation for the efficacy of TMZ.The third study (paper III) investigated international practices for analyzing tumor MGMT promoter methylation status. MGMT analysis can be conducted by various laboratory methods, which in some cases can provide opposing results regarding the MGMT methylation status of the patient´s tumor. This can lead to incorrect treatment recommendations. To establish which methods and cut-offs that are regularly used to determine tumor MGMT status in the clinic, an international survey was provided to those working in the field. We also inquired about opinions regarding an international consensus on how MGMT should be tested. The 152 respondents reported several methodologies and different cut-off levels also for the same method. A majority of respondents warrant international guidelines.In conclusion, the results of the 2 randomized trials contribute to individualized treatment recommendations for patients affected by GBM or astrocytoma grade III. The results of the survey regarding analyses of MGMT clarify the current problematic situation. The request of the respondents regarding international guidelines might contribute to their future development, so that personalized treatment recommendations can be improved.
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