| 1. |
- El-Sayed, R., et al.
(författare)
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Degradation of pristine and oxidized single wall carbon nanotubes by CYP3A4
- 2019
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Ingår i: Biochemical and Biophysical Research Communications. - : Elsevier BV. - 0006-291X .- 1090-2104. ; 515:3, s. 487-492
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Tidskriftsartikel (refereegranskat)abstract
- Carbon nanotubes (CNTs) are a class of carbon based nanomaterials which have attracted substantial attention in recent years as they exhibit outstanding physical, mechanical and optical properties. In the last decade many studies have emerged of the underlying mechanisms behind CNT toxicity including malignant transformation, the formation of granulomas, inflammatory responses, oxidative stress, DNA damage and mutation. In the present investigation, we studied the biodegradation of single-walled carbon nanotubes (SWCNTs) by Cytochrome P450 enzymes (CYP3A4) through using Raman spectroscopy. CYP3A4 is known isozyme accountable for metabolizing various endogenous and exogenous xenobiotics. CYP3A4 is expressed dominantly in the liver and other organs including the lungs. Our results suggest that CYP3A4 has a higher affinity for p-SWNTs compared to c-SWNTs. HEK293 cellular viability was not compromised when incubated with SWNT. However, CYP3A4 transfected HEK293 cell line showed no digestion of c-SWNTs after incubation for 96 h. Cellular uptake of c-SWNTs was observed by electron microscopy and localization of c-SWNTs was confirmed in endosomal vesicles and in the cytoplasm. This is the first study CYP3A4 degrading both p-SWNTs and c-SWNTs in an in vitro setup. Interestingly, our results show that CYP3A4 is more proficient in degrading p-SWNTs than c-SWNTs. We also employed computational modeling and docking assessments to develop a further understanding of the molecular interaction mechanism. © 2019 Elsevier Inc.
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| 2. |
- Lin, Yingbo, et al.
(författare)
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SUMO-modified insulin-like growth factor 1 receptor (IGF-1R) increases cell cycle progression and cell proliferation
- 2017
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Ingår i: Journal of Cellular Physiology. - : John Wiley & Sons. - 0021-9541 .- 1097-4652. ; 232:10, s. 2722-2730
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Tidskriftsartikel (refereegranskat)abstract
- Increasing number of studies have shown nuclear localization of the insulin-like growth factor 1 receptor (nIGF-1R) in tumor cells and its links to adverse clinical outcome in various cancers. Any obvious cell physiological roles of nIGF-1R have, however, still not been disclosed. Previously, we reported that IGF-1R translocates to cell nucleus and modulates gene expression by binding to enhancers, provided that the receptor is SUMOylated. In this study, we constructed stable transfectants of wild type IGF1R (WT) and triple-SUMO-site-mutated IGF1R (TSM) using igf1r knockout mouse fibroblasts (R-). Cell clones (R-WT and R-TSM) expressing equal amounts of IGF1R were selected for experiments. Phosphorylation of IGF-1R, Akt, and Erk upon IGF-1 stimulation was equal in R-WT and R-TSM. WT was confirmed to enter nuclei. TSM did also undergo nuclear translocation, although to a lesser extent. This may be explained by that TSM heterodimerizes with insulin receptor, which is known to translocate to cell nuclei. R-WT proliferated substantially faster than R-TSM, which did not differ significantly from the empty vector control. Upon IGF-1 stimulationG1-S-phase progression of R-WT increased from 12 to 38%, compared to 13 to 20% of R-TSM. The G1-S progression of R-WT correlated with increased expression of cyclin D1, A, and CDK2, as well as downregulation of p27. This suggests that SUMO-IGF-1R affects upstream mechanisms that control and coordinate expression of cell cycle regulators. Further studies to identify such SUMO-IGF-1R dependent mechanisms seem important.
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| 3. |
- Nilsson, Tina, et al.
(författare)
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An induced pluripotent stem cell t(7;12)(q36;p13) acute myeloid leukemia model shows high expression of MNX1 and a block in differentiation of the erythroid and megakaryocytic lineages
- 2022
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 151:5, s. 770-782
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Tidskriftsartikel (refereegranskat)abstract
- Acute myeloid leukemia (AML) results from aberrant hematopoietic processes and these changes are frequently initiated by chromosomal translocations. One particular subtype, AML with translocation t(7;12)(q36;p13), is found in children diagnosed before 2 years of age. The mechanisms for leukemogenesis induced by t(7;12) is not understood, in part because of the lack of efficient methods to reconstruct the leukemia-associated genetic aberration with correct genomic architecture and regulatory elements. We therefore created induced pluripotent stem cell (iPSC) lines that carry the translocation t(7;12) using CRISPR/Cas9. These t(7;12) iPSC showed propensity to differentiate into all three germ layers, confirming retained stem cell properties. The potential for differentiation into hematopoietic stem and progenitor cells (HSPC) was shown by expression of CD34, CD43 and CD45. Compared with the parental iPSC line, a significant decrease in cells expressing CD235a and CD41a was seen in the t(7;12) iPSC-derived HSPC (iHSPC), suggesting a block in differentiation. Moreover, colony formation assay showed an accumulation of cells at the erythroid and myeloid progenitor stages. Gene expression analysis revealed significant down-regulation of genes associated with megakaryocyte differentiation and up-regulation of genes associated with myeloid pathways but also genes typically seen in AML cases with t(7;12). Thus, this iPSC t(7;12) leukemia model of the t(7;12) AML subtype constitutes a valuable tool for further studies of the mechanisms for leukemia development and to find new treatment options.
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| 4. |
- Waraky, Ahmed, et al.
(författare)
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Aberrant MNX1 expression associated with t(7;12)(q36;p13) pediatric acute myeloid leukemia induces the disease through altering histone methylation.
- 2024
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Ingår i: Haematologica. - 1592-8721. ; 109:3, s. 725-739
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Tidskriftsartikel (refereegranskat)abstract
- Certain subtypes of acute myeloid leukemia (AML) in children have inferior outcome, such as AML with translocation t(7;12)(q36;p13) leading to a MNX1::ETV6 fusion along with high expression of MNX1. We have identified the transforming event in this AML and possible ways of treatment. Retroviral expression of MNX1 was able to induce AML in mice, with similar gene expression and pathway enrichment to t(7;12) AML patient data. Importantly, this leukemia was only induced in immune incompetent mice using fetal but not adult hematopoietic stem and progenitor cells. The restriction in transforming capacity to cells from fetal liver is in alignment with t(7;12)(q36;p13) AML being mostly seen in infants. Expression of MNX1 led to increased histone 3 lysine 4 mono-, di- and trimethylation, reduction in H3K27me3, accompanied with changes in genome-wide chromatin accessibility and genome expression, likely mediated through MNX1 interaction with the methionine cycle and methyltransferases. MNX1 expression increased DNA damage, depletion of the Lin- /Sca1+/c-Kit+ population and skewing toward the myeloid lineage. These effects, together with leukemia development, was prevented by pretreatment with the S-adenosylmethionine analog Sinefungin. In conclusion, we have shown the importance of MNX1 in development of AML with t(7;12), supporting a rationale for targeting MNX1 and downstream pathways.
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| 5. |
- Waraky, Ahmed
(författare)
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Insulin-like growth factor 1 receptor, novel functions and future possibilities
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Insulin like growth factor-1 receptor (IGF-1R) has been shown to be important for cancer cell growth and survival, and is often overexpressed in malignant and premalignant tissues. Ligand binding to IGF-1R induces transphosphorylation and activation of the receptor, leading to subsequent activation of the phosphatidyl inositol-3 kinase (PI3K), the mitogen-activated protein kinase (MAPK) and the 14-3-3 pathways. Most of these pathways are shared by other receptor tyrosine kinases. Inhibition of these pathways using specific IGF-1R antibodies has, however, failed in large trials on cancer patients. This opens the possibilities for alternative signaling pathways. Recently, IGF-1R was shown to be SUMOylated and translocated to the cell nucleus. In the nucleus it binds to enhancer-like regions, and regulates expression of genes including CCND1 and AXIN2, and phosphorylates Histone3. The expression of nuclear IGF-1R has also been linked to increased cell growth and aggressive phenotype in cancer. In paper I the effects of picropodophyllin (PPP), an inhibitor of IGF-1R, on cell cycle progression were studied. Previous studies have indicated that PPP treated cells arrest in G2/M. We found that PPP induced G2/M arrest through interfering with microtubule dynamics causing prolonged mitotic arrest and mitotic catastrophe in an IGF-1R independent manner. This mechanism of PPP may contribute to its efficacy in treatment of cancer patients. In paper II the roles of SUMOylated IGF-1R in regulating cell proliferation and cell cycle progression were investigated. We provided evidence that SUMOylation of IGF-1R increases G1/S phase transition through inducing expression of cyclins (D, A and B) and upregulating CDK2. Cells expressing SUMOylated IGF-1R also proliferated faster and formed more colonies in soft agar compared to cells expressing IGF1R with mutated SUMO-binding sites. In paper III we investigated potential binding partners to nuclear IGF-1R in human embryonic stem cells (hESC). We found that nuclear IGF-1R associates with PCNA and phosphorylates it, not only in hESCs but also in other cell types. The nuclear IGF-1R-induced PCNA phosphorylation was followed by ubiquitination of PCNA, probably through DNA damage tolerance (DDT)-dependent E2/E3 ligases (e.g. Rad18 and UBC13). Our data suggest that IGF-1R may contribute to activation of DDT, as externally induced DNA damage in IGF-1R negative cells led to G1 cell cycle arrest and larger S-phase fork stalling compared to cells expressing IGF-1R. In summary, the achieved results may contribute in understanding the complexity of IGF-1R’s roles in cell growth and maintenance of genome stability, as well as the shown mitotic block induced by PPP may be a mechanism that favors anti-IGF-1R treatment in cancer.
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| 6. |
- Yang, Chen, et al.
(författare)
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Nuclear IGF1R interact with PCNA to preserve DNA replication after DNA-damage in a variety of human cancers
- 2020
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Ingår i: PLOS ONE. - : Public Library Science. - 1932-6203. ; 15:7
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Tidskriftsartikel (refereegranskat)abstract
- Nuclear IGF1R has been linked to poor outcome in cancer. We recently showed that nuclear IGF1R phosphorylates PCNA and increases DNA damage tolerance. In this paper we aimed to describe this mechanism in cancer tissue as well as in cancer cell lines. In situ proximity ligation assay identified frequent IGF1R and PCNA colocalization in many cancer types. IGF1R/PCNA colocalization was more frequently increased in tumor cells than in adjacent normal, and more prominent in areas with dysplasia and invasion. However, the interaction was often lost in tumors with poor response to neoadjuvant treatment and most metastatic lesions. In two independent cohorts of serous ovarian carcinomas and oropharyngeal squamous cell carcinomas, stronger IGF1R/PCNA colocalization was significantly associated with a higher overall survival. Ex vivo irradiation of ovarian cancer tissue acutely induced IGF1R/PCNA colocalization together with ?H2AX-foci formations. In vitro, RAD18 mediated mono-ubiquitination of PCNA during replication stress was dependent on IGF1R kinase activity. DNA fiber analysis revealed that IGF1R activation could rescue stalled DNA replication forks, but only in cancer cells with baseline IGF1R/PCNA interaction. We believe that the IGF1R/PCNA interaction is a basic cellular mechanism to increase DNA stress tolerance during proliferation, but that this mechanism is lost with tumor progression in conjunction with accumulated DNA damage and aberrant strategies to tolerate genomic instability. To exploit this mechanism in IGF1R targeted therapy, IGF1R inhibitors should be explored in the context of concomitant induction of DNA replication stress as well as in earlier clinical stages than previously tried.
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