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- Dimberg, Lina, et al.
(författare)
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Ectopic and IFN-induced expression of Fas overcomes resistance to Fas-mediated apoptosis in multiple myeloma cells.
- 2005
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020.
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Tidskriftsartikel (refereegranskat)abstract
- Multiple myeloma (MM) is an as yet incurable B cell malignancy. Increased survival in vitro is a hallmark of MM cells, implying that a therapeutic potential may lie in circumventing anti-apoptotic signals. We have previously reported that interferons (IFNs) sensitize MM cells to Fas/CD95-mediated apoptosis (1). In the present study, we explore the mechanism underlying this effect. In a wide screening of apoptosis-related genes, Apo2L/TRAIL and Fas were identified as IFN-targets. Sensitization to Fas-mediated apoptosis by IFNs was not affected by blocking Apo2L/TRAIL, suggesting that Apo2L/TRAIL is not a key mediator in this process. In contrast, we found that an elevated Fas expression was functionally linked to increased susceptibility to Fas-mediated apoptosis. This was further supported by the finding that IFN-treatment enhanced Fas-mediated caspase-8 activation, one of the earliest signaling events down-stream receptor activation. In addition, IFN treatment attenuated the IL-6 dependent activation of Stat3, interfering with a known survival-pathway in MM that has previously been linked with resistance to Fas-mediated apoptosis. Taken together, our results show that IFN-induced up-regulation of Fas sensitizes MM cells to Fas-mediated apoptosis and suggest that attenuation of Stat3 activation may be a potentially important event in this process.
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- Dimberg, Lina Y., et al.
(författare)
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Stat1 activation attenuates IL-6 induced Stat3 activity but does not alter apoptosis sensitivity in multiple myeloma
- 2012
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Ingår i: BMC Cancer. - : Springer Science and Business Media LLC. - 1471-2407. ; 12, s. 318-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Multiple myeloma (MM) is at present an incurable malignancy, characterized by apoptosis-resistant tumor cells. Interferon (IFN) treatment sensitizes MM cells to Fas-induced apoptosis and is associated with an increased activation of Signal transducer and activator of transcription (Stat)1. The role of Stat1 in MM has not been elucidated, but Stat1 has in several studies been ascribed a pro-apoptotic role. Conversely, IL-6 induction of Stat3 is known to confer resistance to apoptosis in MM. Methods: To delineate the role of Stat1 in IFN mediated sensitization to apoptosis, sub-lines of the U-266-1970 MM cell line with a stable expression of the active mutant Stat1C were utilized. The influence of Stat1C constitutive transcriptional activation on endogenous Stat3 expression and activation, and the expression of apoptosis-related genes were analyzed. To determine whether Stat1 alone would be an important determinant in sensitizing MM cells to apoptosis, the U-266-1970-Stat1C cell line and control cells were exposed to high throughput compound screening (HTS). Results: To explore the role of Stat1 in IFN mediated apoptosis sensitization of MM, we established sublines of the MM cell line U-266-1970 constitutively expressing the active mutant Stat1C. We found that constitutive nuclear localization and transcriptional activity of Stat1 was associated with an attenuation of IL-6-induced Stat3 activation and up-regulation of mRNA for the pro-apoptotic Bcl-2 protein family genes Harakiri, the short form of Mcl-1 and Noxa. However, Stat1 activation alone was not sufficient to sensitize cells to Fas-induced apoptosis. In a screening of > 3000 compounds including bortezomib, dexamethasone, etoposide, suberoylanilide hydroxamic acid (SAHA), geldanamycin (17-AAG), doxorubicin and thalidomide, we found that the drug response and IC50 in cells constitutively expressing active Stat1 was mainly unaltered. Conclusion: We conclude that Stat1 alters IL-6 induced Stat3 activity and the expression of pro-apoptotic genes. However, this shift alone is not sufficient to alter apoptosis sensitivity in MM cells, suggesting that Stat1 independent pathways are operative in IFN mediated apoptosis sensitization.
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- Ivarsson, Lovisa, et al.
(författare)
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Changes in testing and incidence of Chlamydia trachomatis and Neisseria gonorrhoeae : the possible impact of the COVID-19 pandemic in the three Scandinavian countries
- 2022
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Ingår i: Infectious Diseases. - : Taylor & Francis. - 2374-4235 .- 2374-4243. ; 52:9, s. 623-631
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Tidskriftsartikel (refereegranskat)abstract
- Background: This study aimed to investigate what impact the COVID-19 pandemic and its associated restrictions had on Chlamydia trachomatis and Neisseria gonorrhoeae infections in Sweden, Denmark and Norway, countries with very different governmental strategies for handling this pandemic.Methods: Retrospective analysis of data collected via requests to Swedish regions and to health authorities in Denmark and Norway. The data were collected for the years 2018-2020 and the data from Sweden were more detailed.Results: When the pandemic restrictions were installed in 2020, the number of reported chlamydia cases decreased. The decline was most pronounced in Norway 10.8% (2019: n = 28,446; 2020: n = 25,444) while it was only 3.1% in Denmark (2019: n = 35,688; 2020: n = 34,689) and 4.3% in Sweden (2019: n = 34,726; 2020: n = 33,339). Nucleic acid amplifications tests for chlamydia decreased in Sweden (10%) and Norway (18%) in 2020 compared to 2019, while in Denmark a 21% decrease was noted in April 2020 but thereafter increased to a higher level than 2019. The number of reported gonorrhoea cases decreased in Sweden (17%) and in Norway (39%) in 2020 compared to 2019, while a 21% increase was noted in Denmark.Conclusions: Pandemic restrictions had an impact on the number of reported chlamydia infections in all three countries, but only temporarily and did not seem to be correlated to the restriction levels. The number of reported gonorrhoea infections in Sweden and Norway significantly decreased but not in Denmark. Pandemic restrictions appear to have had a limited effect on the spread of chlamydia and gonorrhoea.
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