| 1. |
- Jönsson Videsäter, Kerstin
(författare)
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Expression of multidrug resistance genes and proteins and effect of selenite in anthracycline-resistant human tumor cell lines
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Treatment failure due to development of drug resistance is a serious complication in cancer treatment and the major cause of death in these patients. This thesis has focused on to gain knowledge about the mechanisms of multidrug resistance and to establish in vitro methods to characterize the resistant tumor cell phenotype. As a new agent in the context of multidrug resistance, selenite was investigated. The ATP bioluminescence assay was developed for cytotoxicity studies and compared to a differential staining cytotoxicity assay (DiSC) by evaluation of tumor cells from 32 patients with acute myelocytic leukemia. The ATP assay correlated to the DiSC assay (r=0.8). The resistance of the doxorubicin resistant HL-60-R cells correlated with mRNA expression and amplification of the multidrug resistance gene (MDR-1). The MDR-1 gene amplification correlated also to the expression levels of the P-glycoprotein. In the doxorubicin resistant U-1285dox900 cells, the resistance correlated with the MRP1 gene and the protein expression whereas the MDR-1 gene or P-glycoprotein expression was not detectable. The cross-resistance profile in U-1285dox900 or HL-60-R did not include melphalane or CdA implying inability of P-gp and MRP1 to transport these drugs. A low cross-resistance to idarubicin compared to daunorubicin in U-1285dox900 cells was associated with a higher accumulation due to a slower outward transport of idarubicin. A low crossresistance to idarubicin suggests that it could be an effective drug for treatment of leukemias that overexpress MRP1. The resistance modifier verapamil significantly restored the intracellular uptake and enhanced the cytotoxic effect of anthracyclines in both MDR-1 and MRP1 overexpressing sublines, whereas co-incubation of daunorubicin or idarubicin with the gluthatione synthetase inhibitor, buthionine sulphoximine only restored sensitivity in the MRP1 expressing U-1285dox900 cells but not in the MDR-1 expressing HL-60-R sublines. The two doxorubicin-resistant lung carcinoma cell lines U-1285dox900 and GLC4/Adr were 3- and 4-fold respectively more sensitive to selenite toxicity than wild type cells. Necrosis was seen in the U-1285 after exposure to high selenite concentrations. Lower selenite concentrations induced massive apoptosis in the doxorubicin resistant-U-1285dox900 cells. The apoptosis was caspase-3 independent. Selenite exposure did not significantly affect the expression of the multi-drug resistant proteins. The activity of thioredoxin reductase (TrxR) was higher (50 and 25% respectively) in the drug-resistant U-1285dox900 and GLC4/Adr cell lines compared to wild type cells and was upon selenite exposure increased only 30% in drugresistant compared to a 4-fold increase in sensitive U-1285 cells. The activity of glutathione reductase increased 4-fold after selenite exposure of the U-1285 cells, but did not increase in the drug-resistant subline. Analysis of TrxR enzymatic activities and protein levels in these cells revealed a co-augmentation with selenite concentration. Maximum increase of TrxR was seen up to 1 µM in both sublines. A break point was noted at 10 µM selenite were the sensitive cells could increase the activity of TrxR whereas the doxorubicin-resistant U- 1285dox900 cells decreased their TrxR activity. Our results demonstrate pronounced selective selenium-mediated apoptosis in therapy-resistant cells and suggest that redox regulation through the thioredoxin system can be a target for cancer therapy.
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| 2. |
- Jönsson-Videsäter, Kerstin, et al.
(författare)
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Selenite-induced apoptosis in doxorubicin-resistant cells and effects on the thioredoxin system.
- 2004
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Ingår i: Biochemical Pharmacology. - : Elsevier BV. - 0006-2952. ; 67:3, s. 513-522
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Tidskriftsartikel (refereegranskat)abstract
- Selenium treatment of the doxorubicin-resistant cell line, U-1285dox, derived from human small cell carcinoma of the lung, resulted in massive apoptosis. This effect appeared maximal at 2 days after addition of selenite. The apoptosis was caspase-3 independent as revealed by Western blot analysis, activity measurement and by using caspase inhibitors. Induction of apoptosis was significantly more pronounced and occurred after addition of lower concentrations of selenite in the doxorubicin-resistant cells compared to the parental doxorubicin-sensitive cells. High levels of selenite caused necrosis in the doxorubicin-sensitive cells. Analysis of enzymatic activity (insulin reduction) of thioredoxin reductase (TrxR) and TrxR protein concentration, measured by ELISA, revealed increasing activity and protein levels after treatment with increasing concentrations of selenium. Maximum relative increase was induced up to 1 μM in both sublines and at this selenium level the concentrations of TrxR measured as insulin reducing activity or ELISA immunoreactivity were nearly identical. Increasing concentrations of selenite up to 10 μM resulted in increased activity and concentration of TrxR in the sensitive subline but decreasing levels in the resistant subline. The level of truncated Trx (tTrx) was higher in the resistant U-1285dox cells but the level did not change with increasing selenite concentrations. Our results demonstrate pronounced selective selenium-mediated apoptosis in therapy-resistant cells and suggest that redox regulation through the thioredoxin system is an important target for cancer therapy.
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| 3. |
- Löfgren, Christina, et al.
(författare)
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Higher plasma but not intracellular concentrations after infusion with liposomal daunorubicin compared with conventional daunorubicin in adult acute myeloid leukemia
- 2007
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Ingår i: Therapeutic Drug Monitoring. - New York : Raven P.. - 0163-4356 .- 1536-3694. ; 29:5, s. 626-631
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Tidskriftsartikel (refereegranskat)abstract
- To investigate the plasma and intracellular pharmacokinetics of liposomal daunorubicin (DaunoXome) in comparison with conventional daunorubicin, 14 patients aged 28 to 60 years with newly diagnosed acute myeloid leukemia were treated for 1 day with DaunoXome (50 mg/m) and for 2 days with daunorubicin (50 mg/m) with concomitant Ara-C (7 days, 200 mg/m, continuous IV). Eleven of the 14 patients entered complete remission; 9 are still alive. Pharmacokinetic profiles were obtained by blood sampling at appropriate intervals on days 1 to 4. Daunorubicin and daunorubicinol concentrations in plasma and in peripheral leukemic blast cells were measured by high-performance liquid chromatography. Following liposomal daunorubicin administration, the peak values and plasma area under the curve (AUC) were more than 100 times higher than after administration of conventional daunorubicin (AUC, 176 vs. 0.98 micromol/L x hour), but the intracellular AUCs were comparable (759 vs. 715 micromol/L x hour). Intracellular concentrations after DaunoXome peaked later and half as high as after daunorubicin. After DaunoXome versus daunorubicin, plasma clearance was 0.001 versus 0.4 micromol/h, respectively. The volume of distribution was 5.5 L for DaunoXome, versus 3640 L for daunorubicin, indicating low tissue affinity for the liposomal formulation. The authors conclude that liposomal daunorubicin, DaunoXome, yields 2-log higher plasma concentrations but similar intracellular concentrations of daunorubicin and its metabolite daunorubicinol than does free daunorubicin.
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| 4. |
- Rolandsdotter, Helena, et al.
(författare)
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Exclusive Enteral Nutrition : Clinical Effects and Changes in Mucosal Cytokine Profile in Pediatric New Inflammatory Bowel Disease
- 2019
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Ingår i: Nutrients. - : MDPI. - 2072-6643. ; 11:2
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Tidskriftsartikel (refereegranskat)abstract
- Exclusive Enteral Nutrition (EEN) is the first-line treatment in children with Crohn's disease (CD) for induction of remission. However, the mode of action remains conjectural. The aim of this study was to investigate whether the effect of EEN is paralleled by changes in the mucosal cytokine profiles (MCP). Twelve children with new onset inflammatory bowel disease (IBD) received induction treatment with a polymeric EEN. We assessed clinical, endoscopic and histologic scoring before and after EEN. Twelve colonic cytokines were analyzed by Polymerase Chain Reaction (PCR) in six of the IBD patients at onset and after EEN as well as in six non-IBD control children at the diagnostic colonoscopy. Twelve children completed 6 weeks of EEN, except from one child who completed 4 weeks. At the control colonoscopy, 83% were in complete clinical remission. Changes were found in the MCPs of individual patients after EEN. In particular, children with IBD showed significantly higher values of Interleukin (IL)-12 (p = 0.008) and IL-23 (p = 0.02) compared to non-IBD controls at the diagnostic colonoscopy. Furthermore, an overall change in proinflammatory cytokines was noted in the IBD-group after treatment. Further studies are warranted to understand the role of EEN in MCP.
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