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JARID1B promotes metastasis and epithelial-mesenchymal transition via PTEN/AKT signaling in hepatocellular carcinoma cells.

Tang B, Qi G, Tang F, Yuan S, Wang Z, Liang X, Li B, Yu S, Liu J, Huang Q, Wei Y, Zhai R, Lei B, Yu H, Jiao X, He S - Oncotarget (2015)

Bottom Line: In addition Kaplan-Meier survival analysis showed that high expression of JARID1B was associated with decreased overall survival of HCC patients.Mechanistically, we found JARID1B exerts its function through modulation of H3K4me3 at the PTEN gene promoter, which was associated with inactive PTEN transcription.Our results, for the first time, portray a pivotal role of JARID1B in stimulating metastatic behaviors of HCC cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Hepatobiliary Surgery, Guilin Medical University, Affiliated Hospital, Guilin, Guangxi, People's Republic of China.

ABSTRACT
JARID1B is a member of the family of JmjC domain-containing proteins that removes methyl residues from methylated lysine 4 on histone H3 lysine 4 (H3K4). JARID1B has been proposed as an oncogene in many types of tumors; however, its role and underlying mechanisms in hepatocellular carcinoma (HCC) remain unknown. Here we show that JARID1B is elevated in HCC and its expression level is positively correlated with metastasis. In addition Kaplan-Meier survival analysis showed that high expression of JARID1B was associated with decreased overall survival of HCC patients. Overexpression of JARID1B in HCC cells increased proliferation, epithelial-mesenchymal transition, migration and invasion in vitro, and enhanced tumorigenic and metastatic capacities in vivo. In contrast, silencing JARID1B in aggressive and invasive HCC cells inhibited these processes. Mechanistically, we found JARID1B exerts its function through modulation of H3K4me3 at the PTEN gene promoter, which was associated with inactive PTEN transcription. PTEN overexpression blocked JARID1B-driven proliferation, EMT, and metastasis. Our results, for the first time, portray a pivotal role of JARID1B in stimulating metastatic behaviors of HCC cells. Targeting JARID1B may thus be a useful strategy to impede HCC cell invasion and metastasis.

No MeSH data available.


Related in: MedlinePlus

JARID1B downregulates PTEN expression in HCC cellsA, supervised hierarchical clustering of the genes differentially expressed after JARID1B overexpression in HepG2 cells. B, gene set enrichment analysis was carried out using ConceptGen. C and D, protein levels of PTEN, PI3K, p-PI3K, AKT, and p-AKT were measured in HCC cells with JARID1B overexpression (C) or silencing (D) by Western blot assay. E, the abundance of H3 lysine methylation was assessed in HCC cells with JARID1B overexpression by Western blotting using whole-cell lysate; total H3 and β-actin were used as a loading control. F, schematic presentation of three regions relative to the PTEN transcriptional start site used as primers to test histone occupied abundance. G and H, qChIP was performed to assess H3K4me3 occupancy in HepG2-pBabe-JARID1B (G), SK-Hep1-pSuper-shJARID1B (H) or their control cells. IgG was used as negative control (G and H, left). “Percentage of input” indicates the ratio of DNA fragment of each promoter region bound by H3K4me3 to the total amount of input DNA fragment without H3K4me3 antibody pull-down. **, P < 0.01 is based on the Student t test. All results are from three independent experiments. Error bars, SD.
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Figure 7: JARID1B downregulates PTEN expression in HCC cellsA, supervised hierarchical clustering of the genes differentially expressed after JARID1B overexpression in HepG2 cells. B, gene set enrichment analysis was carried out using ConceptGen. C and D, protein levels of PTEN, PI3K, p-PI3K, AKT, and p-AKT were measured in HCC cells with JARID1B overexpression (C) or silencing (D) by Western blot assay. E, the abundance of H3 lysine methylation was assessed in HCC cells with JARID1B overexpression by Western blotting using whole-cell lysate; total H3 and β-actin were used as a loading control. F, schematic presentation of three regions relative to the PTEN transcriptional start site used as primers to test histone occupied abundance. G and H, qChIP was performed to assess H3K4me3 occupancy in HepG2-pBabe-JARID1B (G), SK-Hep1-pSuper-shJARID1B (H) or their control cells. IgG was used as negative control (G and H, left). “Percentage of input” indicates the ratio of DNA fragment of each promoter region bound by H3K4me3 to the total amount of input DNA fragment without H3K4me3 antibody pull-down. **, P < 0.01 is based on the Student t test. All results are from three independent experiments. Error bars, SD.

Mentions: To better understand the mechanisms by which JARID1B engaged in HCC development and progression, we performed gene expression profiling on HepG2-pBabe-JARID1B and its control cells. Microarray analyses identified a list of genes significantly differentially expressed after JARID1B overexpression including downregulation of PTEN (Figure 7A). Furthermore, gene set enrichment analysis indicated that proliferation, neoplasm metastasis and invasion, cell movement and motility, and PTEN related gene signatures were significantly changed in JARID1B overexpression cells (Figure 7B), supporting the idea that JARID1B regulates proliferation, EMT and cancer invasion and metastasis. These data also led us to hypothesize that JARID1B exerts these functions possibly via PTEN. To test this, we first determined whether PTEN is a downstream target of JARID1B in HCC cells. Expression of PTEN in the cells with altered JARID1B expression was further evaluated by qRT-PCR and Western blotting. Huh7-pBabe-JARID1B and HepG2-pBabe-JARID1B cells exhibited greatly increased both PTEN mRNA and protein levels (Supplemental Figure 4A, Figure 7C), whereas silencing JARID1B in SNU423 and SK-Hep1 cells dramatically decreased its mRNA and protein levels (Supplemental Figure 4B, Figure 7D). Suggesting the regulation of PTEN expression by JARID1B is at transcriptional level. It has been shown that PTEN can regulate PI3K/Akt pathway in many tumor cells [24, 25]. So we next examined the role of JARID1B-mediated inhibition of PTEN in the PI3K/Akt pathway. Of note, ectopic JARID1B expression in Huh7 and HepG2 cells remarkably increased the level of phosphorylated PI3K and AKT (Figure 7C), whereas silencing JARID1B in SNU423 and SK-Hep1 cells robustly suppressed phosphorylation of PI3K and AKT (Figure 7D). While both ectopic expression and silencing of JARID1B not altered the expression of PI3K and AKT mRNA levels (Supplemental Figure 4A and 4B).


JARID1B promotes metastasis and epithelial-mesenchymal transition via PTEN/AKT signaling in hepatocellular carcinoma cells.

Tang B, Qi G, Tang F, Yuan S, Wang Z, Liang X, Li B, Yu S, Liu J, Huang Q, Wei Y, Zhai R, Lei B, Yu H, Jiao X, He S - Oncotarget (2015)

JARID1B downregulates PTEN expression in HCC cellsA, supervised hierarchical clustering of the genes differentially expressed after JARID1B overexpression in HepG2 cells. B, gene set enrichment analysis was carried out using ConceptGen. C and D, protein levels of PTEN, PI3K, p-PI3K, AKT, and p-AKT were measured in HCC cells with JARID1B overexpression (C) or silencing (D) by Western blot assay. E, the abundance of H3 lysine methylation was assessed in HCC cells with JARID1B overexpression by Western blotting using whole-cell lysate; total H3 and β-actin were used as a loading control. F, schematic presentation of three regions relative to the PTEN transcriptional start site used as primers to test histone occupied abundance. G and H, qChIP was performed to assess H3K4me3 occupancy in HepG2-pBabe-JARID1B (G), SK-Hep1-pSuper-shJARID1B (H) or their control cells. IgG was used as negative control (G and H, left). “Percentage of input” indicates the ratio of DNA fragment of each promoter region bound by H3K4me3 to the total amount of input DNA fragment without H3K4me3 antibody pull-down. **, P < 0.01 is based on the Student t test. All results are from three independent experiments. Error bars, SD.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4494969&req=5

Figure 7: JARID1B downregulates PTEN expression in HCC cellsA, supervised hierarchical clustering of the genes differentially expressed after JARID1B overexpression in HepG2 cells. B, gene set enrichment analysis was carried out using ConceptGen. C and D, protein levels of PTEN, PI3K, p-PI3K, AKT, and p-AKT were measured in HCC cells with JARID1B overexpression (C) or silencing (D) by Western blot assay. E, the abundance of H3 lysine methylation was assessed in HCC cells with JARID1B overexpression by Western blotting using whole-cell lysate; total H3 and β-actin were used as a loading control. F, schematic presentation of three regions relative to the PTEN transcriptional start site used as primers to test histone occupied abundance. G and H, qChIP was performed to assess H3K4me3 occupancy in HepG2-pBabe-JARID1B (G), SK-Hep1-pSuper-shJARID1B (H) or their control cells. IgG was used as negative control (G and H, left). “Percentage of input” indicates the ratio of DNA fragment of each promoter region bound by H3K4me3 to the total amount of input DNA fragment without H3K4me3 antibody pull-down. **, P < 0.01 is based on the Student t test. All results are from three independent experiments. Error bars, SD.
Mentions: To better understand the mechanisms by which JARID1B engaged in HCC development and progression, we performed gene expression profiling on HepG2-pBabe-JARID1B and its control cells. Microarray analyses identified a list of genes significantly differentially expressed after JARID1B overexpression including downregulation of PTEN (Figure 7A). Furthermore, gene set enrichment analysis indicated that proliferation, neoplasm metastasis and invasion, cell movement and motility, and PTEN related gene signatures were significantly changed in JARID1B overexpression cells (Figure 7B), supporting the idea that JARID1B regulates proliferation, EMT and cancer invasion and metastasis. These data also led us to hypothesize that JARID1B exerts these functions possibly via PTEN. To test this, we first determined whether PTEN is a downstream target of JARID1B in HCC cells. Expression of PTEN in the cells with altered JARID1B expression was further evaluated by qRT-PCR and Western blotting. Huh7-pBabe-JARID1B and HepG2-pBabe-JARID1B cells exhibited greatly increased both PTEN mRNA and protein levels (Supplemental Figure 4A, Figure 7C), whereas silencing JARID1B in SNU423 and SK-Hep1 cells dramatically decreased its mRNA and protein levels (Supplemental Figure 4B, Figure 7D). Suggesting the regulation of PTEN expression by JARID1B is at transcriptional level. It has been shown that PTEN can regulate PI3K/Akt pathway in many tumor cells [24, 25]. So we next examined the role of JARID1B-mediated inhibition of PTEN in the PI3K/Akt pathway. Of note, ectopic JARID1B expression in Huh7 and HepG2 cells remarkably increased the level of phosphorylated PI3K and AKT (Figure 7C), whereas silencing JARID1B in SNU423 and SK-Hep1 cells robustly suppressed phosphorylation of PI3K and AKT (Figure 7D). While both ectopic expression and silencing of JARID1B not altered the expression of PI3K and AKT mRNA levels (Supplemental Figure 4A and 4B).

Bottom Line: In addition Kaplan-Meier survival analysis showed that high expression of JARID1B was associated with decreased overall survival of HCC patients.Mechanistically, we found JARID1B exerts its function through modulation of H3K4me3 at the PTEN gene promoter, which was associated with inactive PTEN transcription.Our results, for the first time, portray a pivotal role of JARID1B in stimulating metastatic behaviors of HCC cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Hepatobiliary Surgery, Guilin Medical University, Affiliated Hospital, Guilin, Guangxi, People's Republic of China.

ABSTRACT
JARID1B is a member of the family of JmjC domain-containing proteins that removes methyl residues from methylated lysine 4 on histone H3 lysine 4 (H3K4). JARID1B has been proposed as an oncogene in many types of tumors; however, its role and underlying mechanisms in hepatocellular carcinoma (HCC) remain unknown. Here we show that JARID1B is elevated in HCC and its expression level is positively correlated with metastasis. In addition Kaplan-Meier survival analysis showed that high expression of JARID1B was associated with decreased overall survival of HCC patients. Overexpression of JARID1B in HCC cells increased proliferation, epithelial-mesenchymal transition, migration and invasion in vitro, and enhanced tumorigenic and metastatic capacities in vivo. In contrast, silencing JARID1B in aggressive and invasive HCC cells inhibited these processes. Mechanistically, we found JARID1B exerts its function through modulation of H3K4me3 at the PTEN gene promoter, which was associated with inactive PTEN transcription. PTEN overexpression blocked JARID1B-driven proliferation, EMT, and metastasis. Our results, for the first time, portray a pivotal role of JARID1B in stimulating metastatic behaviors of HCC cells. Targeting JARID1B may thus be a useful strategy to impede HCC cell invasion and metastasis.

No MeSH data available.


Related in: MedlinePlus