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- Gustafsson, Anna, et al.
(författare)
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Gas6 and the receptor tyrosine kinase Axl in clear cell renal cell carcinoma.
- 2009
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Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 4:10, s. e7575-
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The molecular biology of renal cell carcinoma (RCC) is complex and not fully understood. We have recently found that the expression of the receptor tyrosine kinase Axl in the RCC tumors independently correlates with survival of the patients. PRINCIPAL FINDINGS: Here, we have investigated the role of Axl and its ligand Gas6, the vitamin-K dependent protein product of the growth arrest-specific gene 6, in clear cell RCC (ccRCC) derived cells. The Axl protein was highly expressed in ccRCC cells deficient in functional von Hippel-Lindau (VHL) protein, a tumor suppressor gene often inactivated in ccRCC. VHL reconstituted cells expressed decreased levels of Axl protein, but not Axl mRNA, suggesting VHL to regulate Axl expression. Gas6-mediated activation of Axl in ccRCC cells resulted in Axl phosphorylation, receptor down-regulation, decreased cell-viability and migratory capacity. No effects of the Gas6/Axl system could be detected on invasion. Moreover, in ccRCC tumor tissues, Axl was phosphorylated and Gas6 gamma-carboxylated, suggesting these molecules to be active in vivo. SIGNIFICANCE: These results provide novel information regarding the complex function of the Gas6/Axl system in ccRCC.
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| 2. |
- Karlsson, Ulf, et al.
(författare)
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Mode of coreceptor use by R5 HIV type 1 correlates with disease stage: a study of paired plasma and cerebrospinal fluid isolates.
- 2009
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Ingår i: AIDS research and human retroviruses. - : Mary Ann Liebert Inc. - 1931-8405 .- 0889-2229. ; 25:12, s. 1297-1305
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Tidskriftsartikel (refereegranskat)abstract
- Through the use of chimeric CXCR4/CCR5 receptors we have previously shown that CCR5-tropic (R5) HIV-1 isolates acquire a more flexible receptor use over time, and that this links to a reduced viral susceptibility to inhibition by the CCR5 ligand RANTES. These findings may have relevance with regards to the efficacy of antiretroviral compounds that target CCR5/virus interactions. Compartmentalized discrepancies in coreceptor use may occur, which could also affect the efficacy of these compounds at specific anatomical sites, such as within the CNS. In this cross-sectional study we have used wild-type CCR5 and CXCR4 as well as chimeric CXCR4/CCR5 receptors to characterize coreceptor use by paired plasma and cerebrospinal fluid (CSF) isolates from 28 HIV-1-infected individuals. Furthermore, selected R5 isolates, with varying chimeric receptor use, were tested for sensitivity to inhibition by the CCR5 antagonist TAK-779. Discordant CSF/plasma virus coreceptor use was found in 10/28 patients. Low CD4+ T cell counts correlated strongly with a more flexible mode of R5 virus CCR5 usage, as disclosed by an increased ability to utilize chimeric CXCR4/CCR5 receptors, specifically receptor FC-2. Importantly, an elevated ability to utilize chimeric receptors correlated with a reduced susceptibility to inhibition by TAK-779. Our findings show that a discordant CSF and plasma virus coreceptor use is not uncommon. Furthermore, we provide support for an emerging paradigm, where the acquisition of a more flexible mode of CCR5 usage is a key event in R5 virus pathogenesis. This may, in turn, negatively impact the efficacy of CCR5 antagonist treatment in late stage HIV-1 disease.
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| 4. |
- Ljungberg, Liza, 1980-
(författare)
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Angiotensin-Converting Enzyme : Effects of Smoking and Other Risk Factors for Cardiovascular Diseases
- 2009
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Cardiovascular diseases (CVDs) are the most common cause of death in Western countries. Smoking, hypertension, diabetes mellitus and hypercholesterolemia are considered as major risk factors. However, the underlying mechanisms by which these factors cause CVDs are not entirely clear. Angiotensin-converting enzyme (ACE) is a key enzyme in the renin-angiotensin-aldosterone system, converting angiotensin I to the vasoactive peptide angiotensin II. Besides being an important factor for normal regulation of blood pressure, ACE appears to be involved in the pathogenesis of atherosclerosis. Previous studies have shown an upregulation of ACE in atherosclerotic plaques. There is genetic polymorphism in the ACE gene (ACE I/D polymorphism) which is strongly connected to the levels of ACE in plasma, but has also been associated with higher risk for cardiovascular diseases. The aim of this thesis was to investigate ACE in vitro and in vivo, in relation to cardiovascular risk factors and CVDs. The results showed that nicotine and nicotine metabolites increase ACE activity in human endothelial cells in vitro. Smoking was associated with increased plasma ACE levels. This effect might be mediated by nicotine and nicotine metabolites. These results could explain one cellular mechanism by which smoking exerts negative effect on the vascular system. Extract of oral snuff inhibited ACE in human endothelial cells and in serum, whereas extract of cigarette smoke had no effect on endothelial ACE. If these results have any physiological relevance remains to be investigated. Cardiovascular risk factors and CVDs were associated with increased levels of ACE in plasma. No association between ACE D/D genotype and CVDs was found. Based on these results we suggest that an increased level of ACE, rather than ACE genotype, is associated with increased risk for CVDs.
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| 5. |
- Ljungberg, Liza, 1980-, et al.
(författare)
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Effect of Nicotine and Nicotine Metabolites on Angiotensin-Converting Enzyme in Human Endothelial Cells
- 2008
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Ingår i: Endothelium. - Philadelphia, USA : Informa UK Limited. - 1062-3329 .- 1029-2373. ; 15:5-6, s. 239-245
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Tidskriftsartikel (refereegranskat)abstract
- Nicotine has been shown to induce endothelial dysfunction, which is an early marker of atherosclerosis. Nicotine undergoes extensive metabolism in the liver, forming a number of major and minor metabolites. There are very limited data on the effect of nicotine metabolites on the cardiovascular system. This study investigates the effects of nicotine and the nicotine metabolites, cotinine, cotinine-N-oxide, nicotine-1-N-oxide, norcotinine, trans-3-hydroxycotinine, on angiotensin-converting enzyme (ACE) in human endothelial cells. Cultured endothelial cells obtained from human umbilical cord vein (HUVECs) were stimulated with nicotine or nicotine metabolites in concentrations similar to those observed in plasma during smoking. ACE activity and expression were analyzed using commercial kits. The results showed that nicotine and nicotine metabolites can increase both activity and expression of ACE. However, a marked individual variation in the response to the drugs was observed. This variation was not associated with the ACE insertion/deletion polymorphism. Tobacco contains numerous chemical compounds, and the underlying cause for development of atherosclerosis in smokers is probably multifactorial. The results from this study could explain one cellular mechanism by which smoking exerts negative effect on the vascular system.
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| 9. |
- Papworth, Karin, 1964-, et al.
(författare)
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Expression of erythropoietin and its receptor in human renal cell carcinoma
- 2009
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Ingår i: Tumor Biology. - : Springer Science and Business Media LLC. - 1010-4283 .- 1423-0380. ; 30:2, s. 86-92
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To investigate the prognostic impact of erythropoietin (EPO) and EPO-receptor (EPO-R) expression in tumour as well as serum EPO in patients with renal cell carcinoma (RCC). Methods: Using immunohistochemistry, EPO and EPO-R were assessed in tissue microarrays from 195 RCCs. RCC type, TNM stage, nuclear grade, survival, EPO and haemoglobin (Hb) levels in blood were registered. Results: Strong expression of EPO and EPO-R in tumour tissue was found in 83 and 56%, respectively. EPO and EPO-R expression differed between RCC types. Serum EPO and blood Hb did not correlate to the expression of EPO or EPO-R. A positive correlation was found between the expression of EPO and EPO-R (p = 0.028). Survival was not related to tumour EPO, whereas strong EPO-R expression indicated a non-significantly worse prognosis. Serum EPO correlated positively to TNM stage and nuclear grade and negatively to survival. A multivariate analysis showed that TNM stage and nuclear grade were independent prognostic factors. Tumour EPO and EPO-R expression as well as serum EPO added no independent prognostic information. Conclusion: No correlation between EPO or EPO-R in tumour tissue and serum EPO or blood Hb was found. Neither EPO, EPO-R in tumour tissue nor serum EPO are independent prognostic factors.
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| 10. |
- Papworth, Karin, 1964-, et al.
(författare)
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Parathyroid hormone-related protein and serum calcium in patients with renal cell carcinoma
- 2005
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Ingår i: Tumor Biology. - : Springer Science and Business Media LLC. - 1010-4283 .- 1423-0380. ; 26:4, s. 201-206
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To evaluate serum parathyroid hormone-related protein (PTHrP) in relation to serum calcium and clinical outcome of patients with renal cell carcinoma. Methods: Sera from 243 patients with renal cell carcinoma were collected prior to therapy. Serum PTHrP was analyzed using an immunoradiometric assay. Tumour stage, nuclear grade, corrected serum calcium, and survival were assessed. Results: Serum PTHrP was detectable in 37/243 sera (15%) and hypercalcaemia (≥2.60 mmol/l) in 32/220 (15%). A positive correlation between serum PTHrP and serum calcium was found (r = 0.326; p < 0.01). Following subdivision of the material, based on storage time, the frequency of detectable serum PTHrP seemed to decrease with time. Serum calcium, but not serum PTHrP, was correlated to tumour stage (p < 0.001). Survival was similar for patients with detectable and undetectable PTHrP, but those with hypercalcaemia had a significantly shorter survival time compared to those with normal serum calcium (p < 0.001). A multivariate analysis showed that tumour stage and serum calcium were independent prognostic factors, but not grade or PTHrP. Conclusions: A positive relation of serum PTHrP to serum calcium was demonstrated in patients with renal cell carcinoma. Hypercalcaemia but not serum PTHrP predicted a worse prognosis.
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