| 1. |
- Aare, Sudhakar, et al.
(författare)
-
Mechanisms underlying the sparing of masticatory versus limb muscle function in an experimental critical illness model
- 2011
-
Ingår i: Physiological Genomics. - : American Physiological Society. - 1094-8341 .- 1531-2267. ; 43:24, s. 1334-1350
-
Tidskriftsartikel (refereegranskat)abstract
- Acute quadriplegic myopathy (AQM) is a common debilitating acquired disorder in critically ill intensive care unit (ICU) patients which is characterized by tetraplegia/generalized weakness of limb and trunk muscles. Masticatory muscles, on the other hand, are typically spared or less affected, yet the mechanisms underlying this striking muscle-specific difference remain unknown. This study aims to evaluate physiological parameters and the gene expression profiles of masticatory and limb muscles exposed to factors suggested to trigger AQM, such as mechanical ventilation, immobilization, neuromuscular blocking agents (NMBA), corticosteroids (CS) and sepsis for five days by using a unique porcine model mimicking the ICU conditions. Single muscle fiber cross-sectional area and force-generating capacity, i.e., maximum force normalized to fiber cross-sectional area (specific force), revealed maintained masseter single muscle fiber cross-sectional area and specific-force after five days exposure to all triggering factors. This is in sharp contrast to observations in limb and trunk muscles, showing a dramatic decline in specific force in response to five days exposure to the triggering factors. Significant differences in gene expression were observed between craniofacial and limb muscles, indicating a highly complex and muscle specific response involving transcription and growth factors, heat shock proteins, matrix metalloproteinase inhibitor, oxidative stress responsive elements and sarcomeric proteins underlying the relative sparing of cranial versus spinal nerve innervated muscles during exposure to the ICU intervention.
|
|
| 2. |
- Banduseela, Varuna C., et al.
(författare)
-
Gene expression and muscle fiber function in a porcine ICU model
- 2009
-
Ingår i: Physiological Genomics. - : American Physiological Society. - 1094-8341 .- 1531-2267. ; 39:3, s. 141-159
-
Tidskriftsartikel (refereegranskat)abstract
- Skeletal muscle wasting and impaired muscle function in response to mechanical ventilation and immobilization in intensive care unit (ICU) patients are clinically challenging partly due to 1) the poorly understood intricate cellular and molecular networks and 2) the unavailability of an animal model mimicking this condition. By employing a unique porcine model mimicking the conditions in the ICU with long-term mechanical ventilation and immobilization, we have analyzed the expression profile of skeletal muscle biopsies taken at three time points during a 5-day period. Among the differentially regulated transcripts, extracellular matrix, energy metabolism, sarcomeric and LIM protein mRNA levels were downregulated, while ubiquitin proteasome system, cathepsins, oxidative stress responsive genes and heat shock proteins (HSP) mRNAs were upregulated. Despite 5 days of immobilization and mechanical ventilation single muscle fiber cross-sectional areas as well as the maximum force generating capacity at the single muscle fiber level were preserved. It is proposed that HSP induction in skeletal muscle is an inherent, primary, but temporary protective mechanism against protein degradation. To our knowledge, this is the first study that isolates the effect of immobilization and mechanical ventilation in an ICU condition from various other cofactors.
|
|
| 3. |
- Banduseela, Varuna, et al.
(författare)
-
Impaired autophagy, chaperone expression, and protein synthesis in response to critical illness interventions in porcine skeletal muscle
- 2013
-
Ingår i: Physiological Genomics. - : American Physiological Society. - 1094-8341 .- 1531-2267. ; 45:12, s. 477-486
-
Tidskriftsartikel (refereegranskat)abstract
- Critical illness myopathy (CIM) is characterized by a preferential loss of the motor protein myosin, muscle wasting, and impaired muscle function in critically ill intensive care unit (ICU) patients. CIM is associated with severe morbidity and mortality and has a significant negative socioeconomic effect. Neuromuscular blocking agents, corticosteroids, sepsis, mechanical ventilation, and immobilization have been implicated as important risk factors, but the causal relationship between CIM and the risk factors has not been established. A porcine ICU model has been used to determine the immediate molecular and cellular cascades that may contribute to the pathogenesis prior to myosin loss and extensive muscle wasting. Expression profiles have been compared between pigs exposed to the ICU interventions, i.e., mechanically ventilated, sedated, and immobilized for 5 days, with pigs exposed to critical illness interventions, i.e., neuromuscular blocking agents, corticosteroids, and induced sepsis in addition to the ICU interventions for 5 days. Impaired autophagy as well as impaired chaperone expression and protein synthesis were observed in the skeletal muscle in response to critical illness interventions. A novel finding in this study is impaired core autophagy machinery in response to critical illness interventions, which when in concert with downregulated chaperone expression and protein synthesis may collectively affect the proteostasis in skeletal muscle and may exacerbate the disease progression in CIM.
|
|
| 4. |
- Baskaran, Sathishkumar, et al.
(författare)
-
Primary glioblastoma cells for precision medicine : a quantitative portrait of genomic (in)stability during the first 30 passages
- 2018
-
Ingår i: Neuro-Oncology. - : OXFORD UNIV PRESS INC. - 1522-8517 .- 1523-5866. ; 20:8, s. 1080-1091
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Primary glioblastoma cell (GC) cultures have emerged as a key model in brain tumor research, with the potential to uncover patient-specific differences in therapy response. However, there is limited quantitative information about the stability of such cells during the initial 20-30 passages of culture.Methods: We interrogated 3 patient-derived GC cultures at dense time intervals during the first 30 passages of culture. Combining state-of-the-art signal processing methods with a mathematical model of growth, we estimated clonal composition, rates of change, affected pathways, and correlations between altered gene dosage and transcription.Results: We demonstrate that GC cultures undergo sequential clonal takeovers, observed through variable proportions of specific subchromosomal lesions, variations in aneuploid cell content, and variations in subpopulation cell cycling times. The GC cultures also show significant transcriptional drift in several metabolic and signaling pathways, including ribosomal synthesis, telomere packaging and signaling via the mammalian target of rapamycin, Wnt, and interferon pathways, to a high degree explained by changes in gene dosage. In addition to these adaptations, the cultured GCs showed signs of shifting transcriptional subtype. Compared with chromosomal aberrations and gene expression, DNA methylations remained comparatively stable during passaging, and may be favorable as a biomarker.Conclusion: Taken together, GC cultures undergo significant genomic and transcriptional changes that need to be considered in functional experiments and biomarker studies that involve primary glioblastoma cells.
|
|
| 5. |
|
|
| 6. |
- Birgisson, Helgi, et al.
(författare)
-
Microsatellite instability and mutations in BRAF and KRAS are significant predictors of disseminated disease in colon cancer
- 2015
-
Ingår i: BMC Cancer. - : Springer Science and Business Media LLC. - 1471-2407 .- 1471-2407. ; 15
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Molecular alterations are well studied in colon cancer, however there is still need for an improved understanding of their prognostic impact. This study aims to characterize colon cancer with regard to KRAS, BRAF, and PIK3CA mutations, microsatellite instability (MSI), and average DNA copy number, in connection with tumour dissemination and recurrence in patients with colon cancer. Methods: Disease stage II-IV colon cancer patients (n = 121) were selected. KRAS, BRAF, and PIK3CA mutation status was assessed by pyrosequencing and MSI was determined by analysis of mononucleotide repeat markers. Genome-wide average DNA copy number and allelic imbalance was evaluated by SNP array analysis. Results: Patients with mutated KRAS were more likely to experience disease dissemination (OR 2.75; 95% CI 1.28-6.04), whereas the opposite was observed for patients with BRAF mutation (OR 0.34; 95% 0.14-0.81) or MSI (OR 0.24; 95% 0.09-0.64). Also in the subset of patients with stage II-III disease, both MSI (OR 0.29; 95% 0.10-0.86) and BRAF mutation (OR 0.32; 95% 0.16-0.91) were related to lower risk of distant recurrence. However, average DNA copy number and PIK3CA mutations were not associated with disease dissemination. Conclusions: The present study revealed that tumour dissemination is less likely to occur in colon cancer patients with MSI and BRAF mutation, whereas the presence of a KRAS mutation increases the likelihood of disseminated disease.
|
|
| 7. |
|
|
| 8. |
- Eriksson, Anna, 1977-, et al.
(författare)
-
AKN-028 induces cell cycle arrest, downregulation of Myc associated genes and a dose dependent reduction of kinase activity in acute myeloid leukemia
- 2014
-
Ingår i: Biochemical Pharmacology. - : Elsevier. - 0006-2952 .- 1356-1839. ; 87:2, s. 284-291
-
Tidskriftsartikel (refereegranskat)abstract
- AKN-028 is a novel tyrosine kinase inhibitor with preclinical activity in acute myeloid leukemia (AML), presently undergoing investigation in a phase I/II study. It is a potent inhibitor of the FMS-like kinase 3 (FLT3) but shows in vitro activity in a wide range of AML samples. In the present study, we have characterized the effects of AKN-028 on AML cells in more detail. AKN-028 induced a dose-dependent G(0)/arrest in AML cell line MV4-11. Treatment with AKN-028 caused significantly altered gene expression in all AML cell types tested (430 downregulated, 280 upregulated transcripts). Subsequent gene set enrichment analysis revealed enrichment of genes associated with the proto-oncogene and cell cycle regulator c-Myc among the downregulated genes in both AKN-028 and midostaurin treated cells. Kinase activity profiling in AML cell lines and primary AML samples showed that tyrosine kinase activity, but not serine/threonine kinase activity, was inhibited by AKN-028 in a dose dependent manner in all samples tested, reaching approximately the same level of kinase activity. Cells sensitive to AKN-028 showed a higher overall tyrosine kinase activity than more resistant ones, whereas serine/threonine kinase activity was similar for all primary AML samples. In summary, AKN-028 induces cell cycle arrest in AML cells, downregulates Myc-associated genes and affect several signaling pathways. AML cells with high global tyrosine kinase activity seem to be more sensitive to the cytotoxic effect of AKN-028 in vitro.
|
|
| 9. |
|
|
| 10. |
- Fryknäs, Mårten, et al.
(författare)
-
STAT1 signaling is associated with acquired crossresistance to doxorubicin and radiation in myeloma cell lines
- 2007
-
Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 120:1, s. 189-195
-
Tidskriftsartikel (refereegranskat)abstract
- The myeloma cell line RPMI 8226/S and its doxorubicin resistant subline 8226/Dox40 were used as models to explore the potential importance of the STAT1 signaling pathway in drug and radiation resistance. The 40-fold doxorubicin resistant subline 8226/Dox40 was found to be crossresistant to single doses of 4 and 8 Gy of radiation. A genome-wide mRNA expression study comparing the 8226/Dox40 cell line to its parental line was performed to identify the underlying molecular mechanisms. Seventeen of the top 50 overexpressed genes have previously been implicated in the STAT1 signaling pathway. STAT1 was over expressed both at the mRNA and protein level. Moreover, analyses of nuclear extracts showed higher abundance of phosphorylated STAT1 (Tyr 701) in the resistant subline. Preexposure of the crossresistant cells to the STAT1 inhibiting drug fludarabine reduced expression of overexpressed genes and enhanced the effects of both doxorubicin and radiation. These results show that resistance to doxorubicin and radiation is associated with increased STAT1 signaling and can be modulated by fludarabine. The data support further development of therapies combining fludarabine and radiation.
|
|
