| 1. |
- Backman, Samuel, 1994-
(författare)
-
Molecular studies of endocrine tumors : Insights from genetics and epigenetics
- 2020
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Endocrine tumors may be benign or malignant and may occur in any of the hormone producing tissues. They share several biological characteristics, including a low mutation-burden, and may co-occur in several hereditary tumor syndromes. The aim of this thesis was to identify genetic and epigenetic aberrations in endocrine tumors.In paper I we performed a comprehensive DNA methylation analysis of 39 pheochromocytomas/paragangliomas as well as 4 normal adrenal medullae on the HumanMethylation27 BeadChip array. We validated two previously described clusters based on DNA methylation with distinct genetic associations.In Paper II we performed a transcriptomic analysis of 15 aldosterone producing adenomas. CTNNB1-mutated tumors were found to form a distinct subgroup based on gene expression and to share gene expression similarities with non-aldosterone producing adrenocortical tumors with CTNNB1 mutations, including overexpression of AFF3 and ISM1.In paper III we used whole genome sequencing to identify germline genetic variants in 14 patients with Multiple Endocrine Neoplasia type 1 previously found to be wildtype for the MEN1 gene on routine clinical testing. Three patients were found to carry previously undetected MEN1 mutations. Two patients were confirmed to have phenocopies caused by variants affecting CASR or CDC73. In total 9/14 patients were not found to have a disease-causing germline variant, suggesting that the syndrome may in some cases be due to chance co-occurrence of several sporadic tumors.In paper IV RNA-Seq and whole genome sequencing of a cohort of SI-NETs selected on the basis of unusually short or long survival was performed in order to identify disease causing genes and potential prognostic factors. We confirmed known genetic aberrations and found rare variants in known cancer driver genes. Based on gene expression two clusters that differ in prognosis were detected. Moreover, through integration of copy number variation data and gene expression, we identied novel potential disease causing genes.
|
|
| 2. |
- Bayadsi, Haytham, 1987-
(författare)
-
Tumour stromal and demographical factors affecting the metastatic aggressiveness of small differentiated papillary thyroid cancers in Sweden
- 2023
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: The incidence of papillary thyroid cancer (PTC) has been increasing over the recent decades, especially that of small papillary thyroid cancers (sPTCs) (≤ 20mm in size). sPTCs are generally classified as low risk cancers with a very favourable diagnosis, yet some of these cancers still cause locoregional and distant metastasis, recurrence and even death.Aims: To investigate the role of tumour stromal, environmental and demographical factors affecting the metastatic aggressiveness of sPTCs in Sweden.Material & Methods: Selected tumour stromal proteins (Types I (Col1) and IV (Col4) collagens, alpha smooth muscle actin (a-SMA) and matrix metallopeptidase 9 (MMP-9)) were analysed for their role in metastatic disease (Paper I). Demographic and clinicopathological differences regarding recurrence between metastasized vs. non-metastasized sPTCs in Sweden were studied in 2 registry-based retrospective observational cohort studies (Papers II & III). The geographic distribution of patients with sPTC in Sweden was pinpointed and layered with maps of gamma radiation deposits of radionuclides Caesium-137 (Cs-137), Thorium-232 (Th-232), Uranium-238 (U-238) and Potassium-40 (K-40) using different spatial analysis methods (Paper IV).Results: Col1 and Col4 were significantly more expressed in the non-metastatic tumours compared with metastatic ones. Patients with N1b disease were younger, had a smaller tumour size and higher recurrence rates compared to patients with N0 and N1a disease. The mean number of metastatic LNs at initial surgery was higher in the N1b group than the N1a group and correlated with more recurrent disease. The prevalence of metastatic sPTC was associated with significantly higher levels of gamma radiation from Th-232, U-238 and K-40.Conclusions: The higher expression of Col1 and Col4 in the non-metastasized tumours indicates a potential protective role in tumour progression. LN stage N1b at diagnosis, and having five or more metastatic nodes, are strong risk factors for cancer recurrence and decreased disease-free survival in sPTC. Environmental factors such as gamma radiation are believed to play a major role in the pathogenesis of the PTC. These findings altogether underscore the importance of LN evaluation, tumour biological as well as environmental factors in sPTC patients, suggesting that the management of these patients should be based on an individual risk stratification instead of a “one size fits all” approach.
|
|
| 3. |
- Berglund, Erik, et al.
(författare)
-
Intracellular concentration of the tyrosine kinase inhibitor imatinib in gastrointestinal stromal tumor cells.
- 2014
-
Ingår i: Anti-Cancer Drugs. - 0959-4973 .- 1473-5741. ; 25:4, s. 415-22
-
Tidskriftsartikel (refereegranskat)abstract
- Gastrointestinal stromal tumor (GIST) is the most common mesenchymal neoplasm in the gastrointestinal tract. In most GISTs, the underlying mechanism is a gain-of-function mutation in the KIT or the PDGFRA gene. Imatinib is a tyrosine kinase inhibitor that specifically blocks the intracellular ATP-binding sites of these receptors. A correlation exists between plasma levels of imatinib and progression-free survival, but it is not known whether the plasma concentration correlates with the intracellular drug concentration. We determined intracellular imatinib levels in two GIST cell lines: the imatinib-sensitive GIST882 and the imatinib-resistant GIST48. After exposing the GIST cells to imatinib, the intracellular concentrations were evaluated using LC-MS (TOF). The concentration of imatinib in clinical samples from three patients was also determined to assess the validity and reliability of the method in the clinical setting. Determination of imatinib uptake fits within detection levels and values are highly reproducible. The GIST48 cells showed significantly lower imatinib uptake compared with GIST882 in therapeutic doses, indicating a possible difference in uptake mechanisms. Furthermore, imatinib accumulated in the tumor tissues and showed intratumoral regional differences. These data show, for the first time, a feasible and reproducible technique to measure intracellular imatinib levels in experimental and clinical settings. The difference in the intracellular imatinib concentration between the cell lines and clinical samples indicates that drug transporters may contribute toward resistance mechanisms in GIST cells. This highlights the importance of further clinical studies to quantify drug transporter expression and measure intracellular imatinib levels in GIST patients.
|
|
| 4. |
- Bränström, Robert, et al.
(författare)
-
Electrical short-circuit in β-cells from a patient with non-insulinoma pancreatogenous hypoglycemic syndrome (NIPHS) : a case report
- 2010
-
Ingår i: Journal of Medical Case Reports. - : Springer Science and Business Media LLC. - 1752-1947. ; 4:1, s. 315-
-
Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Non-insulinoma pancreatogenous hypoglycemic syndrome is a rare disorder among adults, and, to our knowledge, only about 40 cases have been reported in the literature. CASE PRESENTATION: The patient is a previously healthy 35-year-old Caucasian man. His symptoms began four years ago when he suddenly felt weakness in his legs and started sweating for unknown reasons. The symptoms worsened, and laboratory tests revealed hypoglycemia and hyperinsulinemia at the time of the symptoms. All diagnostics attempts using magnetic resonance imaging, computed tomography, and endoscopic ultrasound did not reveal any abnormalities. At this stage, surgical intervention was planned, and a distal 80% pancreatectomy was performed. The histopathologic and immunohistochemical investigations of the pancreas showed an increased number of islets of different sizes, more or less evenly distributed in the gland, but no insulinoma. Patch-clamp recordings from isolated pancreatic β-cells showed that, even at a low glucose concentration (3 mmol/L), the β-cell membrane was depolarized, and action potentials were seen. Surprisingly, in patch-clamp experiments, the addition of diazoxide had a marked effect on K-ATP channel activity and membrane potential, but no effect on insulin levels in vivo before surgery. CONCLUSION: This case report adds new information on the pathogenesis of non-insulinoma pancreatogenous hypoglycemic syndrome, as we performed an electrophysiologic characterization of isolated islet cells. We show, for the first time, that β-cells isolated from a non-insulinoma pancreatogenous hypoglycemic syndrome patient are constantly depolarized, even at low glucose levels, but display normal K-ATP channel physiology.
|
|
| 5. |
- Bränström, Robert
(författare)
-
Metabolic signals and the ATP-sensitive potassium channel in the pancreatic beta-cell
- 1999
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- ATP-sensitive K+ (KATP) channels are widely distributed in a variety of tissues and cell types. KATP channels are comprised of two subunits, a pore forming subunit (Kir6.x) and a regulatory sulfonylurea receptor (SURx). Both subunits are required for fully functional channels. In the present thesis the role of the pancreatic [beta]-cell KATP channel, with regard to oscillations in electrical activity and modulation of channel activity by various compounds as well as the functional organization of channel subunits, were investigated. In the [beta]-cell the KATP channel (comprised of Kir6.2 and SUR1) couples metabolic changes to electrical activity. Although electrophysiological studies during the last decade have provided clues to the complex control of the KATP channel by various nucleotides and pharmacological agents, the metabolic signals responsible for its physiological regulation remain to be clarified. The widely accepted model of glucose-induced insulin secretion involves a number of events. Following glucose metabolism, the ATP/ADP ratio increases, inducing closure of the KATP channel, depolarization of the [beta]-cell plasma membrane and thereby opening of voltage-gated Ca2+ channels. The rise in cytoplasmic free Ca2+ concentration ([Ca2+]i) triggers insulin release. Oscillations in some or all of these signals are thought to play an important role in the pulsatile nature of insulin release. The molecular mechanism underlying these oscillations is unknown but is an important issue since absence of normal oscillations in plasma insulin levels is observed in non-insulin dependent diabetes mellitus. In this thesis, it is shown that KATP channel activity is oscillating in intact [beta]-cells under stimulatory concentrations of glucose, thereby inducing fluctuations in electrical activity and [Ca2+]i. This effect is likely to reflect oscillations in metabolism, since blocking of glucose metabolism induced openings of the KATP channel that correlated with periods of hyperpolarization and lowering in [Ca2+]i. Glucose is metabolized through glycolysis in the cytosol and through the tricarboxylic acid cycle in the mitochondria. The relative role of mitochondrial metabolism has frequently been studied using [alpha]-ketoisocaproate as substrate. In contrast to previous findings, assuming that [alpha]-ketoisocaproate needs to be metabolized in order to close the KATP channel, it is shown that [alpha]-ketoisocaproate reversibly and in a dose-dependent manner inhibits the KATP channel directly. Besides glucose, free fatty acids (FFA) have been demonstrated to play a critical role in insulin secretion. It is shown that the metabolic active form of FFA, long-chain CoA (LC-CoA) esters, are accumulated intracellularly in response to prolonged exposure to elevated FFA, and are potent and chain-length specific activators of the KATP channel. Using a truncated version of Kir6.2 (Kir6.2[delta]C26), which generates channels in the absence of SUR1, it was shown that LC-CoA esters interact directly with Kir6.2. These findings verify that LC-CoA esters have a unique binding site on the KATP channel complex and may be of physiological importance. Finally, KATPchannels are organized as heterooctameric complexes assembled with a 4:4 stoichiometry of Kir6.2 and SUR1. It is shown that SUR1 plays a critical role in the functional organization of Kir6.2 by a mechanism distinct from the ability of SUR1 to recruit Kir6.2 to the membrane and the ability to convey sensitivity to sulfonylurea and MgADP.
|
|
| 6. |
- Daskalakis, Kosmas
(författare)
-
Small Intestinal Neuroendocrine Tumors : Clinical Studies, Novel Serum Biomarkers and Sensitivity to Cytotoxic and Targeted Agents
- 2017
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Small Intestinal Neuroendocrine Tumors (SI-NETs) are indolent neoplasms with an increasing annual incidence of approximately 1/100 000 people. They are often diagnosed at a late stage, restricting treatment efficacy. The aim of this thesis was to investigate clinical aspects of patients with advanced and/or disseminated disease with regard to clinical signs and management of abdominal fibrosis, the role of locoregional surgery and liver transplantation, as well as the ex vivo sensitivity of tumor samples to cytotoxic and targeted agents. Additionally, novel serum biomarkers for the diagnosis and prognosis of SI-NETs were investigated. In Paper I, abdominal fibrosis induced by serotonin and other cytokines from tumor cells, was associated with clinically significant symptoms of intestinal ischemia and/or obstructive uropathy, and was linked to advanced disease. Prompt recognition and minimally invasive intervention with superior mesenteric vein stenting and/or percutaneous nephrostomy and J stent treatment were effective in disease palliation. Paper II challenged the role of prophylactic, upfront locoregional surgery in Stage IV, which conferred no survival advantage in asymptomatic SI-NET patients. The option of delayed surgery as needed seemed to be comparable in all the outcomes examined, whilst also offering the advantage of fewer re-operations for intestinal obstruction in patients with already disseminated disease. Paper III confirmed that most young patients (<65 years) with SI-NET and liver metastases had a favorable survival with standardized multimodality treatment and that survival figures reported after liver transplantation for NETs do not surpass these figures. In Paper IV, 145 biomarkers were analyzed in blood serum using two different multiplex proximity assays. Subsequent ELISA and immunohistochemical analyses identified DcR3, TFF3 and midkine as novel serum biomarkers for SI-NETs. In Paper V, SI-NET samples were profiled with respect to sensitivity ex vivo to a panel of standard chemotherapeutics and targeted agents using a short-term total cell kill assay. SI-NETs exhibited variable but generally intermediate sensitivity ex vivo compared with other cancer diagnoses, calling for individualized selection of therapy.
|
|
| 7. |
- Fröbom, Robin, et al.
(författare)
-
Phase I trial evaluating safety and efficacy of intratumorally administered inflammatory allogeneic dendritic cells (ilixadencel) in advanced gastrointestinal stromal tumors
- 2020
-
Ingår i: Cancer Immunology and Immunotherapy. - : Springer Science and Business Media LLC. - 0340-7004 .- 1432-0851. ; 69:11, s. 2393-2401
-
Tidskriftsartikel (refereegranskat)abstract
- BackgroundThe majority of patients with advanced gastrointestinal stromal tumor (GIST) develop resistance to imatinib, and subsequent treatments have limited efficacy. Ilixadencel (allogeneic inflammatory dendritic cells) is a cell-based immune primer injected intratumorally that previously has been clinically investigated in metastatic renal cell carcinoma and hepatocellular carcinoma.MethodsThe trial was a single arm phase I trial assessing safety and efficacy of ilixadencel in subjects with progressing advanced/metastatic GIST despite ongoing treatment with second or later lines of tyrosine kinase inhibitors (TKI). Three patients were progressing while on sunitinib (second line), one on regorafenib (third line), and two on pazopanib (fourth line). TKI treatment was maintained throughout, while two intratumoral injections of ilixadencel (10 × 106 viable and HLA-DR expressing cells per dose) were administered.ResultsNo severe adverse events were found to be related to ilixadencel administration. Four patients showed continued tumor progression at 3 months per RECIST 1.1 and Choi criteria. One patient (on third line regorafenib) had stable disease for 9 months and another patient (on second line sunitinib) had stable disease at end of study (12 months) as per RECIST 1.1. These two patients developed a partial response as per Choi criteria with a duration of 3 and 6 months, respectively. The median progression-free survival (PFS) was 4.0 months.ConclusionIlixadencel treatment presented an acceptable safety profile among advanced GIST patients who developed resistance to TKI. Encouraging radiological tumor responses were detected in 33% of treated patients, supporting further investigation.
|
|
| 8. |
- Lu, Ming, et al.
(författare)
-
Expression and association of TRPC subtypes with Orai1 and STIM1 in human parathyroid
- 2010
-
Ingår i: Journal of Molecular Endocrinology. - 0952-5041 .- 1479-6813. ; 44:5, s. 285-294
-
Tidskriftsartikel (refereegranskat)abstract
- The mechanism behind Ca2+ entry into the parathyroid cells has been widely debated, and the molecular identities of the responsible ion channels have not been established yet. In this study, we show that the parathyroid cells lack voltage-operated Ca2+ channels. Passive store depletion by thapsigargin, on the other hand, induces a large non-voltage-activated non-selective cation current. The increase in intracellular Ca2+ caused by thapsigargin is attenuated by 2-aminoethoxydiphenyl borate, a blocker of store-operated Ca2+ entry (SOCE). Candidate molecules for non-voltage-operated Ca2+ signaling were investigated. These included members of the transient receptor potential canonical (TRPC) ion channel family, as well as Ca2+ release-activated Ca2+ modulator 1 (Orai1) and stromal interaction molecule 1 (STIM1) that are key proteins in the SOCE pathway. Using RT-PCR screening, quantitative real-time PCR, and western blot, we showed expression of TRPC1, TRPC4, and TRPC6; Orai1; and STIM1 genes and proteins in normal and adenomatous human parathyroid tissues. Furthermore, co-immunoprecipitation experiments demonstrated a ternary complex of TRPC1-Orai1-STIM1, supporting a physical interaction between these molecules in human parathyroid.
|
|
