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- Charitou, Theodosia, et al.
(författare)
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Transcriptional and metabolic rewiring of colorectal cancer cells expressing the oncogenic KRAS(G13D) mutation
- 2019
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Ingår i: British Journal of Cancer. - : NATURE PUBLISHING GROUP. - 0007-0920 .- 1532-1827. ; 121:1, s. 37-50
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Activating mutations in KRAS frequently occur in colorectal cancer (CRC) patients, leading to resistance to EGFRtargeted therapies. METHODS: To better understand the cellular reprogramming which occurs in mutant KRAS cells, we have undertaken a systems-level analysis of four CRC cell lines which express either wild type (wt) KRAS or the oncogenic KRAS(G13D) allele (mtKRAS). RESULTS: RNAseq revealed that genes involved in ribosome biogenesis, mRNA translation and metabolism were significantly upregulated in mtKRAS cells. Consistent with the transcriptional data, protein synthesis and cell proliferation were significantly higher in the mtKRAS cells. Targeted metabolomics analysis also confirmed the metabolic reprogramming in mtKRAS cells. Interestingly, mtKRAS cells were highly transcriptionally responsive to EGFR activation by TGF alpha stimulation, which was associated with an unexpected downregulation of genes involved in a range of anabolic processes. While TGF alpha treatment strongly activated protein synthesis in wtKRAS cells, protein synthesis was not activated above basal levels in the TGF alpha-treated mtKRAS cells. This was likely due to the defective activation of the mTORC1 and other pathways by TGF alpha in mtKRAS cells, which was associated with impaired activation of PKB signalling and a transient induction of AMPK signalling. CONCLUSIONS: We have found that mtKRAS cells are substantially rewired at the transcriptional, translational and metabolic levels and that this rewiring may reveal new vulnerabilities in oncogenic KRAS CRC cells that could be exploited in future.
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| 2. |
- Burke, Jason R., et al.
(författare)
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Bifunctional Substrate Activation via an Arginine Residue Drives Catalysis in Chalcone Isomerases
- 2019
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Ingår i: ACS Catalysis. - : AMER CHEMICAL SOC. - 2155-5435 .- 2155-5435. ; 9:9, s. 8388-8396
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Tidskriftsartikel (refereegranskat)abstract
- Chalcone isomerases are plant enzymes that perform enantioselective oxa-Michael cyclizations of 2'-hydroxychalcones into flavanones. An X-ray crystal structure of an enzyme-product complex combined with molecular dynamics simulations reveal an enzyme mechanism wherein the guanidinium ion of a conserved arginine positions the nucleophilic phenoxide and activates the electrophilic enone for cyclization through Bronsted and Lewis acid interactions. The reaction terminates by asymmetric protonation of the carbanion intermediate syn to the guanidinium. Interestingly, bifunctional guanidine- and urea-based chemical reagents, increasingly used for asymmetric organocatalytic applications, share mechanistic similarities with this natural system. Comparative protein crystal structures and molecular dynamics simulations further demonstrate how two active site water molecules coordinate a hydrogen bond network that enables expanded substrate reactivity for 6'-deoxychalcones in more recently evolved type-2 chalcone isomerases.
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| 3. |
- O'Hurley, Gillian, et al.
(författare)
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Investigation of molecular alterations of AKT-3 in triple-negative breast cancer
- 2014
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Ingår i: Histopathology. - : Wiley. - 0309-0167 .- 1365-2559. ; 64:5, s. 660-670
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Tidskriftsartikel (refereegranskat)abstract
- Aims Triple-negative breast cancer (TNBC) is responsible for a disproportionate number of breast cancer (BC) deaths, owing to its intrinsic aggressiveness and a lack of treatment options, especially targeted therapies. Thus, there is an urgent need for the development of better targeted treatments for TNBC. Molecular alteration of AKT-3 was previously reported in oestrogen receptor (ER)-positive BC. AKT-3 has also been suggested to play a role in hormone-unresponsive BC. The aim of this study was to investigate molecular alterations of AKT-3 in TNBC, to perform associated survival analysis, and to compare these findings with the incidence of AKT-3 molecular alterations in ER-positive BC. Results Our study revealed AKT-3 amplification and deletions in 11% (9/82) and 13% (11/82) of TNBCs, respectively. In contrast, 1% (2/209) of ER-positive BCs were found to have AKT-3 amplifications and deletions. A higher prevalence of AKT-3 copy number gains was observed in TNBC [26% (21/82)] than in ER-positive BC [9% (19/209)]. AKT-3 amplification together with Akt-3 protein expression was negatively associated with recurrence-free survival in TNBC. Furthermore, a negative association between high AKT-3 copy number and recurrence-free survival was observed. Conclusion AKT-3 amplification could represent a potentially relevant oncogenic event in a subset of TNBCs that may, in turn, select cells sensitive to Akt-3 inhibitors.
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