Hypoxia promotes uveal melanoma invasion through enhanced Notch and MAPK activation.
The transcriptional response promoted by hypoxia-inducible factors has been associated with metastatic spread of uveal melanoma. We found expression of hypoxia-inducible factor 1α (HIF-1α) protein in well-vascularized tumor regions as well as in four cell lines grown in normoxia, thus this pathway m...
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doaj-343740fa96234aad82441e00b23e8bbd2020-11-25T01:46:39ZengPublic Library of Science (PLoS)PLoS ONE1932-62032014-01-0198e10537210.1371/journal.pone.0105372Hypoxia promotes uveal melanoma invasion through enhanced Notch and MAPK activation.Laura AsnaghiMichael H LinKah Suan LimKah Jing LimArushi TripathyMurilo WendebornShannath L MerbsJames T HandaAkrit SodhiEli E BarCharles G EberhartThe transcriptional response promoted by hypoxia-inducible factors has been associated with metastatic spread of uveal melanoma. We found expression of hypoxia-inducible factor 1α (HIF-1α) protein in well-vascularized tumor regions as well as in four cell lines grown in normoxia, thus this pathway may be important even in well-oxygenated uveal melanoma cells. HIF-1α protein accumulation in normoxia was inhibited by rapamycin. As expected, hypoxia (1% pO2) further induced HIF-1α protein levels along with its target genes VEGF and LOX. Growth in hypoxia significantly increased cellular invasion of all 5 uveal melanoma lines tested, as did the introduction of an oxygen-insensitive HIF-1α mutant into Mel285 cells with low HIF-1α baseline levels. In contrast, HIF-1α knockdown using shRNA significantly decreased growth in hypoxia, and reduced by more than 50% tumor invasion in four lines with high HIF-1α baseline levels. Pharmacologic blockade of HIF-1α protein expression using digoxin dramatically suppressed cellular invasion both in normoxia and in hypoxia. We found that Notch pathway components, including Jag1-2 ligands, Hes1-Hey1 targets and the intracellular domain of Notch1, were increased in hypoxia, as well as the phosphorylation levels of Erk1-2 and Akt. Pharmacologic and genetic inhibition of Notch largely blocked the hypoxic induction of invasion as did the pharmacologic suppression of Erk1-2 activity. In addition, the increase in Erk1-2 and Akt phosphorylation by hypoxia was partially reduced by inhibiting Notch signaling. Our findings support the functional importance of HIF-1α signaling in promoting the invasive capacity of uveal melanoma cells in both hypoxia and normoxia, and suggest that pharmacologically targeting HIF-1α pathway directly or through blockade of Notch or Erk1-2 pathways can slow tumor spread.http://europepmc.org/articles/PMC4148307?pdf=render |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Laura Asnaghi Michael H Lin Kah Suan Lim Kah Jing Lim Arushi Tripathy Murilo Wendeborn Shannath L Merbs James T Handa Akrit Sodhi Eli E Bar Charles G Eberhart |
spellingShingle |
Laura Asnaghi Michael H Lin Kah Suan Lim Kah Jing Lim Arushi Tripathy Murilo Wendeborn Shannath L Merbs James T Handa Akrit Sodhi Eli E Bar Charles G Eberhart Hypoxia promotes uveal melanoma invasion through enhanced Notch and MAPK activation. PLoS ONE |
author_facet |
Laura Asnaghi Michael H Lin Kah Suan Lim Kah Jing Lim Arushi Tripathy Murilo Wendeborn Shannath L Merbs James T Handa Akrit Sodhi Eli E Bar Charles G Eberhart |
author_sort |
Laura Asnaghi |
title |
Hypoxia promotes uveal melanoma invasion through enhanced Notch and MAPK activation. |
title_short |
Hypoxia promotes uveal melanoma invasion through enhanced Notch and MAPK activation. |
title_full |
Hypoxia promotes uveal melanoma invasion through enhanced Notch and MAPK activation. |
title_fullStr |
Hypoxia promotes uveal melanoma invasion through enhanced Notch and MAPK activation. |
title_full_unstemmed |
Hypoxia promotes uveal melanoma invasion through enhanced Notch and MAPK activation. |
title_sort |
hypoxia promotes uveal melanoma invasion through enhanced notch and mapk activation. |
publisher |
Public Library of Science (PLoS) |
series |
PLoS ONE |
issn |
1932-6203 |
publishDate |
2014-01-01 |
description |
The transcriptional response promoted by hypoxia-inducible factors has been associated with metastatic spread of uveal melanoma. We found expression of hypoxia-inducible factor 1α (HIF-1α) protein in well-vascularized tumor regions as well as in four cell lines grown in normoxia, thus this pathway may be important even in well-oxygenated uveal melanoma cells. HIF-1α protein accumulation in normoxia was inhibited by rapamycin. As expected, hypoxia (1% pO2) further induced HIF-1α protein levels along with its target genes VEGF and LOX. Growth in hypoxia significantly increased cellular invasion of all 5 uveal melanoma lines tested, as did the introduction of an oxygen-insensitive HIF-1α mutant into Mel285 cells with low HIF-1α baseline levels. In contrast, HIF-1α knockdown using shRNA significantly decreased growth in hypoxia, and reduced by more than 50% tumor invasion in four lines with high HIF-1α baseline levels. Pharmacologic blockade of HIF-1α protein expression using digoxin dramatically suppressed cellular invasion both in normoxia and in hypoxia. We found that Notch pathway components, including Jag1-2 ligands, Hes1-Hey1 targets and the intracellular domain of Notch1, were increased in hypoxia, as well as the phosphorylation levels of Erk1-2 and Akt. Pharmacologic and genetic inhibition of Notch largely blocked the hypoxic induction of invasion as did the pharmacologic suppression of Erk1-2 activity. In addition, the increase in Erk1-2 and Akt phosphorylation by hypoxia was partially reduced by inhibiting Notch signaling. Our findings support the functional importance of HIF-1α signaling in promoting the invasive capacity of uveal melanoma cells in both hypoxia and normoxia, and suggest that pharmacologically targeting HIF-1α pathway directly or through blockade of Notch or Erk1-2 pathways can slow tumor spread. |
url |
http://europepmc.org/articles/PMC4148307?pdf=render |
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