| 1. |
- Holm, C, et al.
(författare)
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Phosphorylation of the oestrogen receptor alpha at serine 305 and prediction of tamoxifen resistance in breast cancer
- 2009
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Ingår i: JOURNAL OF PATHOLOGY. - : Wiley. - 0022-3417 .- 1096-9896. ; 217:3, s. 372-379
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Tidskriftsartikel (refereegranskat)abstract
- Phosphorylation of oestrogen receptor a at serine 305 (ER alpha S305-P) induces tamoxifen resistance in experimental studies, but does not influence response to other endocrine agents, such as fulvestrant. We evaluated ER alpha S305-P using immunohistochemistry in 377 breast carcinomas from premenopausal participants of a randomized trial (n = 248) and patients with advanced disease (n = 129). Among the premenopausal patients, adjuvant tamoxifen improved recurrence-free survival (RFS) for ER alpha S305-P-negative tumours (multivariate HR = 0.53, 95% CI 0.32-0.86, p = 0.010), but not for ER alpha S305-P-positive tumours (multivariate HR = 1.01, 95% CI 0.33-3.05, p = 0.99) (interaction p = 0.131). Notably, ER alpha S305-P was not significantly associated with RFS in patients not treated with tamoxifen (multivariate HR = 0.64, 95% CI 0.30-1.37, p = 0.248), indicating that ER alpha S305-P is a marker for treatment outcome rather than tumour progression. Given the direct experimental link between ER alpha S305-P and tamoxifen resistance and these first clinical data suggesting that premenopausal patients with ER alpha S305-P-positive breast cancer are resistant to adjuvant tamoxifen, further research is encouraged to study whether alternative endocrine treatment should be considered for this subgroup.
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| 2. |
- Bergink, S, et al.
(författare)
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DNA damage triggers nucleotide excision repair-dependent monoubiquitylation of histone H2A
- 2006
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Ingår i: Genes & development. - : Cold Spring Harbor Laboratory. - 0890-9369 .- 1549-5477. ; 20:10, s. 1343-1352
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Tidskriftsartikel (refereegranskat)abstract
- Chromatin changes within the context of DNA repair remain largely obscure. Here we show that DNA damage induces monoubiquitylation of histone H2A in the vicinity of DNA lesions. Ultraviolet (UV)-induced monoubiquitylation of H2A is dependent on functional nucleotide excision repair and occurs after incision of the damaged strand. The ubiquitin ligase Ring2 is required for the DNA damage-induced H2A ubiquitylation. UV-induced ubiquitylation of H2A is dependent on the DNA damage signaling kinase ATR (ATM- and Rad3-related) but not the related kinase ATM (ataxia telangiectasia-mutated). Although the response coincides with phosphorylation of variant histone H2AX, H2AX was not required for H2A ubiquitylation. Together our data show that monoubiquitylation of H2A forms part of the cellular response to UV damage and suggest a role of this modification in DNA repair-induced chromatin remodeling.
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| 3. |
- Dantuma, NP, et al.
(författare)
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A dynamic ubiquitin equilibrium couples proteasomal activity to chromatin remodeling
- 2006
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Ingår i: The Journal of cell biology. - : Rockefeller University Press. - 0021-9525 .- 1540-8140. ; 173:1, s. 19-26
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Tidskriftsartikel (refereegranskat)abstract
- Protein degradation, chromatin remodeling, and membrane trafficking are critically regulated by ubiquitylation. The presence of several coexisting ubiquitin-dependent processes, each of crucial importance to the cell, is remarkable. This brings up questions on how the usage of this versatile regulator is negotiated between the different cellular processes. During proteotoxic stress, the accumulation of ubiquitylated substrates coincides with the depletion of ubiquitylated histone H2A and chromatin remodeling. We show that this redistribution of ubiquitin during proteotoxic stress is a direct consequence of competition for the limited pool of free ubiquitin. Thus, the ubiquitin cycle couples various ubiquitin-dependent processes because of a rate-limiting pool of free ubiquitin. We propose that this ubiquitin equilibrium may allow cells to sense proteotoxic stress in a genome-wide fashion.
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