Open AccessHypoxia activates the hedgehog signaling pathway in a ligand‐independent manner by upregulation of Smo transcription in pancreatic cancer
Author(s) -
Onishi Hideya,
Kai Masaya,
Odate Seiichi,
Iwasaki Hironori,
Morifuji Yoshihiro,
Ogino Toshitatsu,
Morisaki Takafumi,
Nakashima Yutaka,
Katano Mitsuo
Publication year - 2011
Publication title -
cancer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.035
H-Index - 141
eISSN - 1349-7006
pISSN - 1347-9032
DOI - 10.1111/j.1349-7006.2011.01912.x
Subject(s) - smoothened , gli1 , cancer research , hedgehog signaling pathway , pancreatic cancer , downregulation and upregulation , hedgehog , transcription factor , sonic hedgehog , gene silencing , biology , mmp9 , cyclopamine , signal transduction , microbiology and biotechnology , cancer , biochemistry , gene , genetics
The hedgehog (Hh) signaling pathway is activated in various types of cancer including pancreatic ductal adenocarcinoma. It has been shown that extremely low oxygen tension (below 1% O 2 ) is found in tumor tissue including pancreatic ductal adenocarcinoma cells (PDAC) and increases the invasiveness of PDAC. To investigate the contribution of the Hh pathway to hypoxia‐induced invasiveness, we examined how hypoxia affects Hh pathway activation and the invasiveness of PDAC. In the present study, three human PDAC lines were cultured under normoxic (20% O 2 ) or hypoxic (1% O 2 ) conditions. Hypoxia upregulated the transcription of Sonic hedgehog ( Shh ), Smoothened ( Smo ), Gli1 and matrix metalloproteinase9 ( MMP9 ) and increased the invasiveness of PDAC. Significantly, neither the addition of recombinant Shh (rhShh) nor the silencing of Shh affected the transcription of these genes and the invasiveness of PDAC. On the other hand, silencing of Smo decreased the transcription of Gli1 and MMP9 and PDAC invasiveness. Silencing of Gli1 or MMP9 decreased PDAC invasiveness. These results suggest that hypoxia activates the Hh pathway of PDAC by increasing the transcription of Smo in a ligand‐independent manner and increases PDAC invasiveness. ( Cancer Sci 2011; 102: 1144–1150)