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Enhanced myeloid differentiation factor 88 promotes tumor metastasis via induction of epithelial-mesenchymal transition in human hepatocellular carcinoma.

Jia RJ, Cao L, Zhang L, Jing W, Chen R, Zhu MH, Guo SW, Wu GB, Fan XY, Wang H, Zhang YY, Zhou XY, Zhao J, Guo YJ - Cell Death Dis (2014)

Bottom Line: In this study, we reported that enhanced expression of MyD88 promoted epithelial-mesenchymal transition (EMT) properties and tumor-initiating capabilities in HCC cells.MyD88 was found to be able to interact with p85, a regulatory subunit of phosphoinositide 3-kinase (PI3-K), independent of TLR/IL-1R-mediated response and caused PI3-K/v-akt murine thymoma viral oncogene homolog (Akt) activation, which resulted in subsequent phosphorylation of glycogen synthase kinase-3β and stabilization of Snail, a critical EMT mediator.Consistently, we observed a significant correlation between MyD88 expression and p-Akt levels in a cohort of HCC patients, and found that the combination of these two parameters have better prognostic value for HCC patients.

View Article: PubMed Central - PubMed

Affiliation: 1] International Joint Cancer Institute, The Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, People's Republic of China [2] School of Pharmacy, Liaocheng University, 1 Hunan Road, Liaocheng 252059, People's Republic of China.

ABSTRACT
Metastasis is the leading cause of death in patients with hepatocellular carcinoma (HCC) after curative resection. Therefore, it is critical to understand the mechanisms underlying tumor metastasis in HCC. We have previously shown that elevated expression of myeloid differentiation factor 88 (MyD88) may promote tumor growth and metastasis in HCC. In this study, we reported that enhanced expression of MyD88 promoted epithelial-mesenchymal transition (EMT) properties and tumor-initiating capabilities in HCC cells. MyD88 was found to be able to interact with p85, a regulatory subunit of phosphoinositide 3-kinase (PI3-K), independent of TLR/IL-1R-mediated response and caused PI3-K/v-akt murine thymoma viral oncogene homolog (Akt) activation, which resulted in subsequent phosphorylation of glycogen synthase kinase-3β and stabilization of Snail, a critical EMT mediator. Consistently, we observed a significant correlation between MyD88 expression and p-Akt levels in a cohort of HCC patients, and found that the combination of these two parameters have better prognostic value for HCC patients. Taken together, these results suggest that elevated MyD88 may facilitate HCC metastasis by promoting EMT properties and tumor-initiating capabilities via PI3-K/Akt pathway.

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MyD88 activates Akt, promoting metastatic potential of HCC cells. (a) MyD88 was overexpressed or knocked down as indicated and the phosphorylation levels of Akt were analyzed by western blot assay. (b, c) The expressions of epithelial marker (E-cadherin) and mesenchymal markers (vimentin and N-cadherin) were detected by western blot assay and immunofluorescence staining after PLC/PRF/5/LV-MyD88 cells were infected with DN-Akt. Scale bar, 25 μm. (d) PLC/PRF/5/LV-MyD88 cells were infected by DN-Akt and the invasive properties were analyzed by invasion assay using Matrigel-coated Corning chamber as described in Materials and Methods. (e) Nude mice were given intrasplenic injections of hepatoma cells and then intragastric administration of MK2206 (the inhibitor of Akt) as described in the Materials and Methods, and photographs of HCC tumors growth in the spleens (above) and livers (below) are shown. The number of tumors in each group (n=4) five weeks after inoculation was counted. Data represent mean±S.D. * indicates P <0.05, ** indicates P <0.01
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fig3: MyD88 activates Akt, promoting metastatic potential of HCC cells. (a) MyD88 was overexpressed or knocked down as indicated and the phosphorylation levels of Akt were analyzed by western blot assay. (b, c) The expressions of epithelial marker (E-cadherin) and mesenchymal markers (vimentin and N-cadherin) were detected by western blot assay and immunofluorescence staining after PLC/PRF/5/LV-MyD88 cells were infected with DN-Akt. Scale bar, 25 μm. (d) PLC/PRF/5/LV-MyD88 cells were infected by DN-Akt and the invasive properties were analyzed by invasion assay using Matrigel-coated Corning chamber as described in Materials and Methods. (e) Nude mice were given intrasplenic injections of hepatoma cells and then intragastric administration of MK2206 (the inhibitor of Akt) as described in the Materials and Methods, and photographs of HCC tumors growth in the spleens (above) and livers (below) are shown. The number of tumors in each group (n=4) five weeks after inoculation was counted. Data represent mean±S.D. * indicates P <0.05, ** indicates P <0.01

Mentions: Accumulating studies have suggested that PI3-K/Akt activation has a momentous role in induction of EMT during tumor progression.28, 29, 30 We have previously reported that downregulation of MyD88 was able to inhibit the intrinsic activation of Akt in HCC-LM3 cells with medium level of endogenous MyD88.13 Here, we found that the phosphorylation level of Akt was fairly increased in PLC/PRF/5 cells with enforced MyD88 expression and decreased in MyD88-silenced Hep3B cells (Figure 3a). Blockage of Akt by DN-Akt, a dominant negative mutant of Akt, dramatically attenuated MyD88-elicited EMT and invasive capability in PLC/PRF/5 cells (Figures 3b and d). Nude mice inoculated with PLC/PRF/5/LV-MyD88 cells in spleen displayed more and larger xenografts in the liver in comparison with control mice. Treatment with Akt inhibitor, MK2206, significantly inhibited the xenograft formation in these mice (Figure 3e).


Enhanced myeloid differentiation factor 88 promotes tumor metastasis via induction of epithelial-mesenchymal transition in human hepatocellular carcinoma.

Jia RJ, Cao L, Zhang L, Jing W, Chen R, Zhu MH, Guo SW, Wu GB, Fan XY, Wang H, Zhang YY, Zhou XY, Zhao J, Guo YJ - Cell Death Dis (2014)

MyD88 activates Akt, promoting metastatic potential of HCC cells. (a) MyD88 was overexpressed or knocked down as indicated and the phosphorylation levels of Akt were analyzed by western blot assay. (b, c) The expressions of epithelial marker (E-cadherin) and mesenchymal markers (vimentin and N-cadherin) were detected by western blot assay and immunofluorescence staining after PLC/PRF/5/LV-MyD88 cells were infected with DN-Akt. Scale bar, 25 μm. (d) PLC/PRF/5/LV-MyD88 cells were infected by DN-Akt and the invasive properties were analyzed by invasion assay using Matrigel-coated Corning chamber as described in Materials and Methods. (e) Nude mice were given intrasplenic injections of hepatoma cells and then intragastric administration of MK2206 (the inhibitor of Akt) as described in the Materials and Methods, and photographs of HCC tumors growth in the spleens (above) and livers (below) are shown. The number of tumors in each group (n=4) five weeks after inoculation was counted. Data represent mean±S.D. * indicates P <0.05, ** indicates P <0.01
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3973199&req=5

fig3: MyD88 activates Akt, promoting metastatic potential of HCC cells. (a) MyD88 was overexpressed or knocked down as indicated and the phosphorylation levels of Akt were analyzed by western blot assay. (b, c) The expressions of epithelial marker (E-cadherin) and mesenchymal markers (vimentin and N-cadherin) were detected by western blot assay and immunofluorescence staining after PLC/PRF/5/LV-MyD88 cells were infected with DN-Akt. Scale bar, 25 μm. (d) PLC/PRF/5/LV-MyD88 cells were infected by DN-Akt and the invasive properties were analyzed by invasion assay using Matrigel-coated Corning chamber as described in Materials and Methods. (e) Nude mice were given intrasplenic injections of hepatoma cells and then intragastric administration of MK2206 (the inhibitor of Akt) as described in the Materials and Methods, and photographs of HCC tumors growth in the spleens (above) and livers (below) are shown. The number of tumors in each group (n=4) five weeks after inoculation was counted. Data represent mean±S.D. * indicates P <0.05, ** indicates P <0.01
Mentions: Accumulating studies have suggested that PI3-K/Akt activation has a momentous role in induction of EMT during tumor progression.28, 29, 30 We have previously reported that downregulation of MyD88 was able to inhibit the intrinsic activation of Akt in HCC-LM3 cells with medium level of endogenous MyD88.13 Here, we found that the phosphorylation level of Akt was fairly increased in PLC/PRF/5 cells with enforced MyD88 expression and decreased in MyD88-silenced Hep3B cells (Figure 3a). Blockage of Akt by DN-Akt, a dominant negative mutant of Akt, dramatically attenuated MyD88-elicited EMT and invasive capability in PLC/PRF/5 cells (Figures 3b and d). Nude mice inoculated with PLC/PRF/5/LV-MyD88 cells in spleen displayed more and larger xenografts in the liver in comparison with control mice. Treatment with Akt inhibitor, MK2206, significantly inhibited the xenograft formation in these mice (Figure 3e).

Bottom Line: In this study, we reported that enhanced expression of MyD88 promoted epithelial-mesenchymal transition (EMT) properties and tumor-initiating capabilities in HCC cells.MyD88 was found to be able to interact with p85, a regulatory subunit of phosphoinositide 3-kinase (PI3-K), independent of TLR/IL-1R-mediated response and caused PI3-K/v-akt murine thymoma viral oncogene homolog (Akt) activation, which resulted in subsequent phosphorylation of glycogen synthase kinase-3β and stabilization of Snail, a critical EMT mediator.Consistently, we observed a significant correlation between MyD88 expression and p-Akt levels in a cohort of HCC patients, and found that the combination of these two parameters have better prognostic value for HCC patients.

View Article: PubMed Central - PubMed

Affiliation: 1] International Joint Cancer Institute, The Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, People's Republic of China [2] School of Pharmacy, Liaocheng University, 1 Hunan Road, Liaocheng 252059, People's Republic of China.

ABSTRACT
Metastasis is the leading cause of death in patients with hepatocellular carcinoma (HCC) after curative resection. Therefore, it is critical to understand the mechanisms underlying tumor metastasis in HCC. We have previously shown that elevated expression of myeloid differentiation factor 88 (MyD88) may promote tumor growth and metastasis in HCC. In this study, we reported that enhanced expression of MyD88 promoted epithelial-mesenchymal transition (EMT) properties and tumor-initiating capabilities in HCC cells. MyD88 was found to be able to interact with p85, a regulatory subunit of phosphoinositide 3-kinase (PI3-K), independent of TLR/IL-1R-mediated response and caused PI3-K/v-akt murine thymoma viral oncogene homolog (Akt) activation, which resulted in subsequent phosphorylation of glycogen synthase kinase-3β and stabilization of Snail, a critical EMT mediator. Consistently, we observed a significant correlation between MyD88 expression and p-Akt levels in a cohort of HCC patients, and found that the combination of these two parameters have better prognostic value for HCC patients. Taken together, these results suggest that elevated MyD88 may facilitate HCC metastasis by promoting EMT properties and tumor-initiating capabilities via PI3-K/Akt pathway.

Show MeSH
Related in: MedlinePlus