Abstract
Background & Aims: HuR is a RNA-binding factor whose expression is commonly upregulated in some human tumor types. We explored the molecular mechanism underlying HuR elevation and its role in gastric cancer tumorigenesis. Methods: HuR expression and subcellular localization were determined by polymerase chain reaction, immunoblot, and immunohistochemical analyses. Its effect on tumor growth was characterized using flow cytometry, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling, and soft agar analyses. Luciferase reporter, chromatin immunoprecipitation, and electrophoretic mobility shift assays were used to measure transcriptional activation by nuclear factor κB (NF-κB) signaling. Results: Compared with normal gastric tissues, HuR was expressed at higher levels in gastric tumors, particularly in advanced versus early tumors; this increase was associated with enhanced cytoplasmic translocation of HuR. HuR overexpression increased proliferation of tumor cells, activating the G1 to S transition of the cell cycle, DNA synthesis, and anchorage-independent growth. Small interfering RNA-mediated knockdown of HuR expression reduced tumor cell proliferation and response to apoptotic stimuli. No genetic or epigenetic alterations of HuR were observed in gastric tumor cell lines or primary tumors; overexpression depended on phosphatidylinositol 3-kinase/AKT signaling and NF-κB activity. AKT activation increased p65/RelA binding to a putative NF-κB binding site in the HuR promoter, the stability of HuR target transcripts, and the cytoplasmic import of HuR. Conclusions: HuR is a direct transcription target of NF-κB; its activation in gastric cancer cell lines depends on phosphatidylinositol 3-kinase/AKT signaling. HuR activation by this pathway has proliferative and antiapoptotic effects on gastric cancer cells.
| Original language | English |
|---|---|
| Journal | Gastroenterology |
| Volume | 135 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - 2008 Dec 1 |
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ASJC Scopus subject areas
- Gastroenterology
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NF-κB Activates Transcription of the RNA-Binding Factor HuR, via PI3K-AKT Signaling, to Promote Gastric Tumorigenesis. / Kang, Min Ju; Ryu, Byung Kyu; Lee, Min Goo; Han, Jikhyon; Lee, Jin Hee; Ha, Tae Kyu; Byun, Do Sun; Chae, Kwon Seok; Lee, Bong Hee; Chun, Hyang Sook; Lee, Kil Yeon; Kim, Hyo Jong; Chi, Sung-Gil.
In: Gastroenterology, Vol. 135, No. 6, 01.12.2008.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - NF-κB Activates Transcription of the RNA-Binding Factor HuR, via PI3K-AKT Signaling, to Promote Gastric Tumorigenesis
AU - Kang, Min Ju
AU - Ryu, Byung Kyu
AU - Lee, Min Goo
AU - Han, Jikhyon
AU - Lee, Jin Hee
AU - Ha, Tae Kyu
AU - Byun, Do Sun
AU - Chae, Kwon Seok
AU - Lee, Bong Hee
AU - Chun, Hyang Sook
AU - Lee, Kil Yeon
AU - Kim, Hyo Jong
AU - Chi, Sung-Gil
PY - 2008/12/1
Y1 - 2008/12/1
N2 - Background & Aims: HuR is a RNA-binding factor whose expression is commonly upregulated in some human tumor types. We explored the molecular mechanism underlying HuR elevation and its role in gastric cancer tumorigenesis. Methods: HuR expression and subcellular localization were determined by polymerase chain reaction, immunoblot, and immunohistochemical analyses. Its effect on tumor growth was characterized using flow cytometry, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling, and soft agar analyses. Luciferase reporter, chromatin immunoprecipitation, and electrophoretic mobility shift assays were used to measure transcriptional activation by nuclear factor κB (NF-κB) signaling. Results: Compared with normal gastric tissues, HuR was expressed at higher levels in gastric tumors, particularly in advanced versus early tumors; this increase was associated with enhanced cytoplasmic translocation of HuR. HuR overexpression increased proliferation of tumor cells, activating the G1 to S transition of the cell cycle, DNA synthesis, and anchorage-independent growth. Small interfering RNA-mediated knockdown of HuR expression reduced tumor cell proliferation and response to apoptotic stimuli. No genetic or epigenetic alterations of HuR were observed in gastric tumor cell lines or primary tumors; overexpression depended on phosphatidylinositol 3-kinase/AKT signaling and NF-κB activity. AKT activation increased p65/RelA binding to a putative NF-κB binding site in the HuR promoter, the stability of HuR target transcripts, and the cytoplasmic import of HuR. Conclusions: HuR is a direct transcription target of NF-κB; its activation in gastric cancer cell lines depends on phosphatidylinositol 3-kinase/AKT signaling. HuR activation by this pathway has proliferative and antiapoptotic effects on gastric cancer cells.
AB - Background & Aims: HuR is a RNA-binding factor whose expression is commonly upregulated in some human tumor types. We explored the molecular mechanism underlying HuR elevation and its role in gastric cancer tumorigenesis. Methods: HuR expression and subcellular localization were determined by polymerase chain reaction, immunoblot, and immunohistochemical analyses. Its effect on tumor growth was characterized using flow cytometry, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling, and soft agar analyses. Luciferase reporter, chromatin immunoprecipitation, and electrophoretic mobility shift assays were used to measure transcriptional activation by nuclear factor κB (NF-κB) signaling. Results: Compared with normal gastric tissues, HuR was expressed at higher levels in gastric tumors, particularly in advanced versus early tumors; this increase was associated with enhanced cytoplasmic translocation of HuR. HuR overexpression increased proliferation of tumor cells, activating the G1 to S transition of the cell cycle, DNA synthesis, and anchorage-independent growth. Small interfering RNA-mediated knockdown of HuR expression reduced tumor cell proliferation and response to apoptotic stimuli. No genetic or epigenetic alterations of HuR were observed in gastric tumor cell lines or primary tumors; overexpression depended on phosphatidylinositol 3-kinase/AKT signaling and NF-κB activity. AKT activation increased p65/RelA binding to a putative NF-κB binding site in the HuR promoter, the stability of HuR target transcripts, and the cytoplasmic import of HuR. Conclusions: HuR is a direct transcription target of NF-κB; its activation in gastric cancer cell lines depends on phosphatidylinositol 3-kinase/AKT signaling. HuR activation by this pathway has proliferative and antiapoptotic effects on gastric cancer cells.
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U2 - 10.1053/j.gastro.2008.08.009
DO - 10.1053/j.gastro.2008.08.009
M3 - Article
VL - 135
JO - Gastroenterology
JF - Gastroenterology
SN - 0016-5085
IS - 6
ER -