Proline-hydroxylated hypoxia-inducible factor 1α (HIF-1α) upregulation in human tumours.
The stabilisation of HIF-α is central to the transcriptional response of animals to hypoxia, regulating the expression of hundreds of genes including those involved in angiogenesis, metabolism and metastasis. HIF-α is degraded under normoxic conditions by proline hydroxylation, which allows for reco...
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Public Library of Science (PLoS)
2014-01-01
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| Series: | PLoS ONE |
| Online Access: | https://doi.org/10.1371/journal.pone.0088955 |
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| author | Cameron E Snell Helen Turley Alan McIntyre Demin Li Massimo Masiero Christopher J Schofield Kevin C Gatter Adrian L Harris Francesco Pezzella |
| author_facet | Cameron E Snell Helen Turley Alan McIntyre Demin Li Massimo Masiero Christopher J Schofield Kevin C Gatter Adrian L Harris Francesco Pezzella |
| author_sort | Cameron E Snell |
| collection | DOAJ |
| description | The stabilisation of HIF-α is central to the transcriptional response of animals to hypoxia, regulating the expression of hundreds of genes including those involved in angiogenesis, metabolism and metastasis. HIF-α is degraded under normoxic conditions by proline hydroxylation, which allows for recognition and ubiquitination by the von-Hippel-Lindau (VHL) E3 ligase complex. The aim of our study was to investigate the posttranslational modification of HIF-1α in tumours, to assess whether there are additional mechanisms besides reduced hydroxylation leading to stability. To this end we optimised antibodies against the proline-hydroxylated forms of HIF-1α for use in formalin fixed paraffin embedded (FFPE) immunohistochemistry to assess effects in tumour cells in vivo. We found that HIF-1α proline-hydroxylated at both VHL binding sites (Pro402 and Pro564), was present in hypoxic regions of a wide range of tumours, tumour xenografts and in moderately hypoxic cells in vitro. Staining for hydroxylated HIF-1α can identify a subset of breast cancer patients with poorer prognosis and may be a better marker than total HIF-1α levels. The expression of unhydroxylated HIF-1α positively correlates with VHL in breast cancer suggesting that VHL may be rate-limiting for HIF degradation. Our conclusions are that the degradation of proline-hydroxylated HIF-1α may be rate-limited in tumours and therefore provides new insights into mechanisms of HIF upregulation. Persistence of proline-hydroxylated HIF-1α in perinecrotic areas suggests there is adequate oxygen to support prolyl hydroxylase domain (PHD) activity and proline-hydroxylated HIF-1α may be the predominant form associated with the poorer prognosis that higher levels of HIF-1α confer. |
| format | Article |
| id | doaj-art-d61ea88e516e49f18f6fe0fe2b4b0515 |
| institution | DOAJ |
| issn | 1932-6203 |
| language | English |
| publishDate | 2014-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj-art-d61ea88e516e49f18f6fe0fe2b4b05152025-08-20T03:10:47ZengPublic Library of Science (PLoS)PLoS ONE1932-62032014-01-0192e8895510.1371/journal.pone.0088955Proline-hydroxylated hypoxia-inducible factor 1α (HIF-1α) upregulation in human tumours.Cameron E SnellHelen TurleyAlan McIntyreDemin LiMassimo MasieroChristopher J SchofieldKevin C GatterAdrian L HarrisFrancesco PezzellaThe stabilisation of HIF-α is central to the transcriptional response of animals to hypoxia, regulating the expression of hundreds of genes including those involved in angiogenesis, metabolism and metastasis. HIF-α is degraded under normoxic conditions by proline hydroxylation, which allows for recognition and ubiquitination by the von-Hippel-Lindau (VHL) E3 ligase complex. The aim of our study was to investigate the posttranslational modification of HIF-1α in tumours, to assess whether there are additional mechanisms besides reduced hydroxylation leading to stability. To this end we optimised antibodies against the proline-hydroxylated forms of HIF-1α for use in formalin fixed paraffin embedded (FFPE) immunohistochemistry to assess effects in tumour cells in vivo. We found that HIF-1α proline-hydroxylated at both VHL binding sites (Pro402 and Pro564), was present in hypoxic regions of a wide range of tumours, tumour xenografts and in moderately hypoxic cells in vitro. Staining for hydroxylated HIF-1α can identify a subset of breast cancer patients with poorer prognosis and may be a better marker than total HIF-1α levels. The expression of unhydroxylated HIF-1α positively correlates with VHL in breast cancer suggesting that VHL may be rate-limiting for HIF degradation. Our conclusions are that the degradation of proline-hydroxylated HIF-1α may be rate-limited in tumours and therefore provides new insights into mechanisms of HIF upregulation. Persistence of proline-hydroxylated HIF-1α in perinecrotic areas suggests there is adequate oxygen to support prolyl hydroxylase domain (PHD) activity and proline-hydroxylated HIF-1α may be the predominant form associated with the poorer prognosis that higher levels of HIF-1α confer.https://doi.org/10.1371/journal.pone.0088955 |
| spellingShingle | Cameron E Snell Helen Turley Alan McIntyre Demin Li Massimo Masiero Christopher J Schofield Kevin C Gatter Adrian L Harris Francesco Pezzella Proline-hydroxylated hypoxia-inducible factor 1α (HIF-1α) upregulation in human tumours. PLoS ONE |
| title | Proline-hydroxylated hypoxia-inducible factor 1α (HIF-1α) upregulation in human tumours. |
| title_full | Proline-hydroxylated hypoxia-inducible factor 1α (HIF-1α) upregulation in human tumours. |
| title_fullStr | Proline-hydroxylated hypoxia-inducible factor 1α (HIF-1α) upregulation in human tumours. |
| title_full_unstemmed | Proline-hydroxylated hypoxia-inducible factor 1α (HIF-1α) upregulation in human tumours. |
| title_short | Proline-hydroxylated hypoxia-inducible factor 1α (HIF-1α) upregulation in human tumours. |
| title_sort | proline hydroxylated hypoxia inducible factor 1α hif 1α upregulation in human tumours |
| url | https://doi.org/10.1371/journal.pone.0088955 |
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