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- Albertsen, L., et al.
(författare)
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Diversion of Flux toward Sesquiterpene Production in Saccharomyces cerevisiae by Fusion of Host and Heterologous Enzymes
- 2011
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Ingår i: Applied and Environmental Microbiology. - 1098-5336 .- 0099-2240. ; 77:3, s. 1033-1040
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Tidskriftsartikel (refereegranskat)abstract
- The ability to transfer metabolic pathways from the natural producer organisms to the well-characterized cell factory Saccharomyces cerevisiae is well documented. However, as many secondary metabolites are produced by collaborating enzymes assembled in complexes, metabolite production in yeast may be limited by the inability of the heterologous enzymes to collaborate with the native yeast enzymes. This may cause loss of intermediates by diffusion or degradation or due to conversion of the intermediate through competitive pathways. To bypass this problem, we have pursued a strategy in which key enzymes in the pathway are expressed as a physical fusion. As a model system, we have constructed several fusion protein variants in which farnesyl diphosphate synthase (FPPS) of yeast has been coupled to patchoulol synthase (PTS) of plant origin (Pogostemon cablin). Expression of the fusion proteins in S. cerevisiae increased the production of patchoulol, the main sesquiterpene produced by PTS, up to 2-fold. Moreover, we have demonstrated that the fusion strategy can be used in combination with traditional metabolic engineering to further increase the production of patchoulol. This simple test case of synthetic biology demonstrates that engineering the spatial organization of metabolic enzymes around a branch point has great potential for diverting flux toward a desired product.
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| 3. |
- Rank, CU, et al.
(författare)
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Asparaginase-Associated Pancreatitis in ALL: Results from the NOPHO ALL2008 Treatment of Patients 1-45 Years
- 2019
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Ingår i: Blood. 134 (Suppl. 1), 3820.. - : American Society of Hematology. - 0006-4971 .- 1528-0020.
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Konferensbidrag (refereegranskat)abstract
- Premature discontinuation of asparaginase reduces cure rate in contemporary acute lymphoblastic leukemia (ALL) treatment. One of the commonest causes of asparaginase truncation is asparaginase-associated pancreatitis (AAP). We prospectively registered AAP during treatment of 2,448 consecutive Nordic/Baltic ALL patients aged 1.0-45.9 years treated according to the Nordic Society of Pediatric Hematology and Oncology (NOPHO) ALL2008 protocol (7/2008-10/2018). The Day 280 cumulative incidence of first-time AAP (including 99% (167/168) of AAP events at this time point) was 8.3% (95% confidence interval (CI) 7.0-9.9) with a median time of 104 days (interquartile range (IQR) 70-145) from ALL diagnosis to AAP, with a median of 10 days (IQR 6-13) from last asparaginase exposure, and after a median number of five asparaginase doses (IQR 3-7, max 14 doses). All patients received polyethylene glycol conjugated Escherichia coli-derived asparaginase as standard treatment. Eighty-five percent (140/164, unknown in N=4) of AAP events were severe (AAP-associated symptoms and/or pancreatic enzymes >3x upper normal limit lasting >72 hours or with hemorrhagic pancreatitis, pancreatic abscess, or pseudocyst). Four age groups were defined: 1.0-4.9, 5.0-8.9, 9.0-16.9, and 17.0-45.9 years-each containing approximately 25% of the AAP events. Compared with patients aged 1.0-4.9 years, adjusted (sex, immunophenotype, and white blood cell count) hazard ratios (HR) of AAP were associated with higher age (5.0-8.9 years: HR 2.3, 95% CI 1.5-3.6, P<.0001; 9.0-16.9 years: HR 2.5, 95% CI 1.6-3.8, P<.0001; and 17.0-45.9 years: HR 2.5, 95% CI 1.6-3.8, P<.0001). When analyzing the odds of developing any AAP-related complication among patients with ≥100 days of follow-up after the AAP diagnosis, older children (≥5.0 years) and adolescents had increased odds of developing any complication compared with younger children aged 1.0-4.9 years, notably a more than six-fold increase among adolescents (5.0-8.9 years: odds ratio (OR) 2.67, 95% CI 1.07-6.68, P=.04 and 9.0-16.9 years: OR 6.52, 95% CI 2.35-18.1, P=.0003)-including acute and permanent insulin need; intensive care unit admission; pancreatic pseudocyst development; recurrent abdominal pain; elevated pancreatic enzymes at last-follow-up; imaging compatible with pancreatitis (pancreatic inflammation/edema/pseudocysts/hemorrhage) at last follow-up; and AAP-related death. Adult age was not associated with development of any AAP-related complication (17.0-45.9 years: OR 2.3, 95% CI 0.9-5.9, P=.07). Three patients aged 8.6, 17.3, and 18.6 years died of first-time AAP within 0-29 days from AAP diagnosis. Of 168 AAP patients, 34 (20%) were re-challenged with asparaginase. Fifty percent (17/34) developed a second episode of AAP-41% being severe (7/17). The median time to a second AAP event from asparaginase re-exposure was 29 days (IQR 16-94) and occurred after a median of two asparaginase doses (range 0-7). Neither age group nor severity of the first AAP was associated with increased hazard of a second AAP event. None of the patients with a second AAP were further re-exposed to asparaginase, and none died of the second AAP. Among a total of 196 ALL relapses, 21 patients have had AAP including 17 patients with asparaginase truncation. However, the hazard of relapse (age- and sex-adjusted) was not increased among AAP patients with asparaginase truncation versus AAP patients with asparaginase re-exposure (5.0-year cumulative incidence of relapse: 13.2% versus 14.2%) (HR 1.0, 95% CI 0.3-3.1, P=1.0). When analyzing time to relapse among AAP patients versus non-AAP patients, no difference in hazard of relapse was found (HR 2.0, 95% CI 0.8-4.9, P=.2). In conclusion, adolescents and young adults tolerated asparaginase treatment as well as children; however, the risk of AAP was higher for patients older than 5.0 years of age with no difference with increasing age. Despite a low AAP-related mortality, the morbidity was considerable and most profound for patients aged 9.0-16.9 years. Since asparaginase re-exposure was associated with a high risk of a second AAP event and neither AAP development nor AAP-related asparaginase truncation was associated with increased relapse risk, asparaginase re-exposure should be attempted only in patients with a high risk of leukemic relapse. Finally, there is an unmet need for preventive strategies toward AAP
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| 4. |
- Rank, Cecilie U., et al.
(författare)
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Asparaginase-Associated Pancreatitis in Acute Lymphoblastic Leukemia : Results From the NOPHO ALL2008 Treatment of Patients 1-45 Years of Age
- 2020
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Ingår i: Journal of Clinical Oncology. - Alexandria : American Society of Clinical Oncology. - 0732-183X .- 1527-7755. ; 38:2, s. 145-154
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Asparaginase-associated pancreatitis (AAP) is common in patients with acute lymphoblastic leukemia (ALL), but risk differences across age groups both in relation to first-time AAP and after asparaginase re-exposure have not been explored.PATIENTS AND METHODS: We prospectively registered AAP (n = 168) during treatment of 2,448 consecutive ALL patients aged 1.0-45.9 years diagnosed from July 2008 to October 2018 and treated according to the Nordic Society of Pediatric Hematology and Oncology (NOPHO) ALL2008 protocol.RESULTS: Compared with patients aged 1.0-9.9 years, adjusted AAP hazard ratios (HRa) were associated with higher age with almost identical HRa (1.6; 95% CI, 1.1 to 2.3; P = .02) for adolescents (10.0-17.9 years) and adults (18.0-45.9 years). The day 280 cumulative incidences of AAP were 7.0% for children (1.0-9.9 years: 95% CI, 5.4 to 8.6), 10.1% for adolescents (10.0 to 17.9 years: 95% CI, 7.0 to 13.3), and 11.0% for adults (18.0-45.9 years: 95% CI, 7.1 to 14.9; P = .03). Adolescents had increased odds of both acute (odds ratio [OR], 5.2; 95% CI, 2.1 to 13.2; P = .0005) and persisting complications (OR, 6.7; 95% CI, 2.4 to 18.4; P = .0002) compared with children (1.0-9.9 years), whereas adults had increased odds of only persisting complications (OR, 4.1; 95% CI, 1.4 to 11.8; P = .01). Fifteen of 34 asparaginase-rechallenged patients developed a second AAP. Asparaginase was truncated in 17/21 patients with AAP who subsequently developed leukemic relapse, but neither AAP nor the asparaginase truncation was associated with increased risk of relapse.CONCLUSION: Older children and adults had similar AAP risk, whereas morbidity was most pronounced among adolescents. Asparaginase re-exposure should be considered only for patients with an anticipated high risk of leukemic relapse, because multiple studies strongly indicate that reduction of asparaginase treatment intensity increases the risk of relapse.
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