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Hypoxia Promotes Gastric Cancer Malignancy Partly through the HIF-1 α Dependent Transcriptional Activation of the Long Non-coding RNA GAPLINC

View Article: PubMed Central - PubMed

ABSTRACT

Hypoxia-inducible factor (HIF) activates the transcription of genes involved in cancer progression. Recently, HIF was reported to regulate the transcription of non-coding RNAs. Here, we show that the transcription of a long non-coding RNA (lncRNA), Gastric Adenocarcinoma Associated, Positive CD44 Regulator, Long Intergenic Non-Coding RNA (GAPLINC), is directly activated by HIF-1α in gastric cancer (GC). GAPLINC was overexpressed in GC tissues and promoted tumor migration and invasive behavior. GAPLINC overexpression was associated with poor prognosis in GC patients. Luciferase reporter assays and chromatin immunoprecipitation assays confirmed that HIF-1α binds to the promoter region of GAPLINC and activates its transcription. GAPLINC knockdown inhibited hypoxia-induced tumor proliferation in vivo. Taken together, our results identified a novel role for HIF transcriptional pathways in GC tumorigenesis mediated by the regulation of the lncRNA GAPLINC, and suggest GAPLINC as a novel therapeutic target for reversing chemoradioresistance and prolonging survival.

No MeSH data available.


Knockdown of GAPLINC with shRNAs. (A) Sequence information of the primers and shRNAs used. (B) Silencing efficiency of transfection using two shRNAs. The results were derived from at least three different experiments (*P < 0.05).
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Figure 3: Knockdown of GAPLINC with shRNAs. (A) Sequence information of the primers and shRNAs used. (B) Silencing efficiency of transfection using two shRNAs. The results were derived from at least three different experiments (*P < 0.05).

Mentions: The results above prompted us to examine the effect of the HIF-1α-GAPLINC axis on tumor growth. GAPLINC was knocked down in MKN45 and SGC7901 cells using two shRNAs (Figure 3). We next assessed cell proliferation, migration, invasion, and apoptosis rate. The CCK8 assay was performed out to examine the functional role of GAPLINC in cell proliferation. Cells were transfected with GAPLINC shRNA or empty vector. Under normoxic conditions (Figure 4A), cell proliferation was decreased in the shGAPLINC group compared with that in the shGAPLINC-NC group in the MKN45 and SGC7901 cell lines (P < 0.05). This suggested that GAPLINC is a carcinogenic factor involved in regulating GC viability. Under hypoxia, the viability of GC cells was inhibited; however, the shGAPLINC group showed a lower survival rate than the shGAPLINC-NC group (P < 0.01), suggesting that GAPLINC plays an important role in sustaining cell survival under hypoxia. EdU incorporation assay results supported this phenomenon (Figure 4B). The proportion of positive cells (green) among total cells (blue) represented the mitotic cell population. Positive cell numbers were lower in shGAPLINC groups than shGAPLINC-NC groups (P < 0.05).


Hypoxia Promotes Gastric Cancer Malignancy Partly through the HIF-1 α Dependent Transcriptional Activation of the Long Non-coding RNA GAPLINC
Knockdown of GAPLINC with shRNAs. (A) Sequence information of the primers and shRNAs used. (B) Silencing efficiency of transfection using two shRNAs. The results were derived from at least three different experiments (*P < 0.05).
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Related In: Results  -  Collection

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Figure 3: Knockdown of GAPLINC with shRNAs. (A) Sequence information of the primers and shRNAs used. (B) Silencing efficiency of transfection using two shRNAs. The results were derived from at least three different experiments (*P < 0.05).
Mentions: The results above prompted us to examine the effect of the HIF-1α-GAPLINC axis on tumor growth. GAPLINC was knocked down in MKN45 and SGC7901 cells using two shRNAs (Figure 3). We next assessed cell proliferation, migration, invasion, and apoptosis rate. The CCK8 assay was performed out to examine the functional role of GAPLINC in cell proliferation. Cells were transfected with GAPLINC shRNA or empty vector. Under normoxic conditions (Figure 4A), cell proliferation was decreased in the shGAPLINC group compared with that in the shGAPLINC-NC group in the MKN45 and SGC7901 cell lines (P < 0.05). This suggested that GAPLINC is a carcinogenic factor involved in regulating GC viability. Under hypoxia, the viability of GC cells was inhibited; however, the shGAPLINC group showed a lower survival rate than the shGAPLINC-NC group (P < 0.01), suggesting that GAPLINC plays an important role in sustaining cell survival under hypoxia. EdU incorporation assay results supported this phenomenon (Figure 4B). The proportion of positive cells (green) among total cells (blue) represented the mitotic cell population. Positive cell numbers were lower in shGAPLINC groups than shGAPLINC-NC groups (P < 0.05).

View Article: PubMed Central - PubMed

ABSTRACT

Hypoxia-inducible factor (HIF) activates the transcription of genes involved in cancer progression. Recently, HIF was reported to regulate the transcription of non-coding RNAs. Here, we show that the transcription of a long non-coding RNA (lncRNA), Gastric Adenocarcinoma Associated, Positive CD44 Regulator, Long Intergenic Non-Coding RNA (GAPLINC), is directly activated by HIF-1&alpha; in gastric cancer (GC). GAPLINC was overexpressed in GC tissues and promoted tumor migration and invasive behavior. GAPLINC overexpression was associated with poor prognosis in GC patients. Luciferase reporter assays and chromatin immunoprecipitation assays confirmed that HIF-1&alpha; binds to the promoter region of GAPLINC and activates its transcription. GAPLINC knockdown inhibited hypoxia-induced tumor proliferation in vivo. Taken together, our results identified a novel role for HIF transcriptional pathways in GC tumorigenesis mediated by the regulation of the lncRNA GAPLINC, and suggest GAPLINC as a novel therapeutic target for reversing chemoradioresistance and prolonging survival.

No MeSH data available.