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Transforming growth factor-β1 induces EMT by the transactivation of epidermal growth factor signaling through HA/CD44 in lung and breast cancer cells.

Li L, Qi L, Liang Z, Song W, Liu Y, Wang Y, Sun B, Zhang B, Cao W - Int. J. Mol. Med. (2015)

Bottom Line: Hyaluronan (HA) has been shown to induce EMT through either TGF-β1 or EGF signaling and to be a regulator of the crosstalk between these two pathways in fibroblasts.In this study, in order to clarify whether HA has the same effect in tumor cells, we utilized the lung cancer cell line, A549, and the breast cancer cell line, MCF-7, and found that the effects of stimulation with TGF-β1 were more potent than those of EGF in regulating the expression of EMT-associated proteins and in enhancing cell migration and invasion.In conclusion, our data demonstrate that TGF-β1 induces EMT by the transactivation of EGF signaling through HA/CD44 in lung and breast cancer cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Tianjin Medical University Cancer Institute and Hospital, Tianjin 300060, P.R. China.

ABSTRACT
Epithelial-mesenchymal transition (EMT), a process closely related to tumor development, is regulated by a variety of signaling pathways and growth factors, such as transforming growth factor-β1 (TGF-β1) and epidermal growth factor (EGF). Hyaluronan (HA) has been shown to induce EMT through either TGF-β1 or EGF signaling and to be a regulator of the crosstalk between these two pathways in fibroblasts. In this study, in order to clarify whether HA has the same effect in tumor cells, we utilized the lung cancer cell line, A549, and the breast cancer cell line, MCF-7, and found that the effects of stimulation with TGF-β1 were more potent than those of EGF in regulating the expression of EMT-associated proteins and in enhancing cell migration and invasion. In addition, we observed that TGF-β1 activated EGF receptor (EGFR) and its downstream AKT and extracellular signal-regulated kinase (ERK) pathways. Furthermore, we found that TGF-β1 upregulated the expression of hyaluronan synthases (HAS1, HAS2 and HAS3) and promoted the expression of CD44, a cell surface receptor for HA, which interacts with EGFR, resulting in the activation of the downstream AKT and ERK pathways. Conversely, treatment with 4-methylumbelliferone (4-MU; an inhibitor of HAS) prior to stimulation with TGF-β1, inhibited the expression of CD44 and EGFR, abolished the interaction between CD44 and EGFR. Furthermore, the use of shRNA targeting CD44 impaired the expression of EGFR, deactivated the AKT and ERK pathways, reversed EMT and decreased the migration and invasion ability of cells. In conclusion, our data demonstrate that TGF-β1 induces EMT by the transactivation of EGF signaling through HA/CD44 in lung and breast cancer cells.

No MeSH data available.


Related in: MedlinePlus

Inhibition of hyaluronan (HA) by 4-methylumbelliferone (4-MU) abolishes the transforming growth factor-β1 (TGF-β1) induced epithelial-mesenchymal transition (EMT). (A and B) Western blot analysis of the expression of downstream pathways and EMT-related proteins, such as E-cadherin, vimentin, Snail and Twist, following stimulation with TGF-β1 or TGF-β1 plus 4-MU. β-actin was used as a loading control. (C) A Transwell assay was carried out to determine the migratory/invasive ability of the cells following stimulation with TGF-β1 and treatment with 4-MU. All graphs represent the means ± SD of 3 independent experiments. The y-axis represents the fold change in the number of cells. *P<0.05 vs. control.
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f5-ijmm-36-01-0113: Inhibition of hyaluronan (HA) by 4-methylumbelliferone (4-MU) abolishes the transforming growth factor-β1 (TGF-β1) induced epithelial-mesenchymal transition (EMT). (A and B) Western blot analysis of the expression of downstream pathways and EMT-related proteins, such as E-cadherin, vimentin, Snail and Twist, following stimulation with TGF-β1 or TGF-β1 plus 4-MU. β-actin was used as a loading control. (C) A Transwell assay was carried out to determine the migratory/invasive ability of the cells following stimulation with TGF-β1 and treatment with 4-MU. All graphs represent the means ± SD of 3 independent experiments. The y-axis represents the fold change in the number of cells. *P<0.05 vs. control.

Mentions: We further investigated the effects of 4-MU on pathway activation. Pathways downstream of EGF/EGFR were shown to be inactivated, the levels of p-ERK and p-AKT were signifi-cantly decreased, whereas the expression levels of total ERK and AKT proteins remained unaltered (Fig. 5A). Moreover, no significant effect on Smad2/3 phosphorylation was observed following treastment with 4-MU, which suggesting suggests that 4-MU suppressed the EGFR pathway rather than the TGF-β1 pathway. In other words, HA contributed to the regulation of TGF-β1-induced EGF/EGFR signaling.


Transforming growth factor-β1 induces EMT by the transactivation of epidermal growth factor signaling through HA/CD44 in lung and breast cancer cells.

Li L, Qi L, Liang Z, Song W, Liu Y, Wang Y, Sun B, Zhang B, Cao W - Int. J. Mol. Med. (2015)

Inhibition of hyaluronan (HA) by 4-methylumbelliferone (4-MU) abolishes the transforming growth factor-β1 (TGF-β1) induced epithelial-mesenchymal transition (EMT). (A and B) Western blot analysis of the expression of downstream pathways and EMT-related proteins, such as E-cadherin, vimentin, Snail and Twist, following stimulation with TGF-β1 or TGF-β1 plus 4-MU. β-actin was used as a loading control. (C) A Transwell assay was carried out to determine the migratory/invasive ability of the cells following stimulation with TGF-β1 and treatment with 4-MU. All graphs represent the means ± SD of 3 independent experiments. The y-axis represents the fold change in the number of cells. *P<0.05 vs. control.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4494581&req=5

f5-ijmm-36-01-0113: Inhibition of hyaluronan (HA) by 4-methylumbelliferone (4-MU) abolishes the transforming growth factor-β1 (TGF-β1) induced epithelial-mesenchymal transition (EMT). (A and B) Western blot analysis of the expression of downstream pathways and EMT-related proteins, such as E-cadherin, vimentin, Snail and Twist, following stimulation with TGF-β1 or TGF-β1 plus 4-MU. β-actin was used as a loading control. (C) A Transwell assay was carried out to determine the migratory/invasive ability of the cells following stimulation with TGF-β1 and treatment with 4-MU. All graphs represent the means ± SD of 3 independent experiments. The y-axis represents the fold change in the number of cells. *P<0.05 vs. control.
Mentions: We further investigated the effects of 4-MU on pathway activation. Pathways downstream of EGF/EGFR were shown to be inactivated, the levels of p-ERK and p-AKT were signifi-cantly decreased, whereas the expression levels of total ERK and AKT proteins remained unaltered (Fig. 5A). Moreover, no significant effect on Smad2/3 phosphorylation was observed following treastment with 4-MU, which suggesting suggests that 4-MU suppressed the EGFR pathway rather than the TGF-β1 pathway. In other words, HA contributed to the regulation of TGF-β1-induced EGF/EGFR signaling.

Bottom Line: Hyaluronan (HA) has been shown to induce EMT through either TGF-β1 or EGF signaling and to be a regulator of the crosstalk between these two pathways in fibroblasts.In this study, in order to clarify whether HA has the same effect in tumor cells, we utilized the lung cancer cell line, A549, and the breast cancer cell line, MCF-7, and found that the effects of stimulation with TGF-β1 were more potent than those of EGF in regulating the expression of EMT-associated proteins and in enhancing cell migration and invasion.In conclusion, our data demonstrate that TGF-β1 induces EMT by the transactivation of EGF signaling through HA/CD44 in lung and breast cancer cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Tianjin Medical University Cancer Institute and Hospital, Tianjin 300060, P.R. China.

ABSTRACT
Epithelial-mesenchymal transition (EMT), a process closely related to tumor development, is regulated by a variety of signaling pathways and growth factors, such as transforming growth factor-β1 (TGF-β1) and epidermal growth factor (EGF). Hyaluronan (HA) has been shown to induce EMT through either TGF-β1 or EGF signaling and to be a regulator of the crosstalk between these two pathways in fibroblasts. In this study, in order to clarify whether HA has the same effect in tumor cells, we utilized the lung cancer cell line, A549, and the breast cancer cell line, MCF-7, and found that the effects of stimulation with TGF-β1 were more potent than those of EGF in regulating the expression of EMT-associated proteins and in enhancing cell migration and invasion. In addition, we observed that TGF-β1 activated EGF receptor (EGFR) and its downstream AKT and extracellular signal-regulated kinase (ERK) pathways. Furthermore, we found that TGF-β1 upregulated the expression of hyaluronan synthases (HAS1, HAS2 and HAS3) and promoted the expression of CD44, a cell surface receptor for HA, which interacts with EGFR, resulting in the activation of the downstream AKT and ERK pathways. Conversely, treatment with 4-methylumbelliferone (4-MU; an inhibitor of HAS) prior to stimulation with TGF-β1, inhibited the expression of CD44 and EGFR, abolished the interaction between CD44 and EGFR. Furthermore, the use of shRNA targeting CD44 impaired the expression of EGFR, deactivated the AKT and ERK pathways, reversed EMT and decreased the migration and invasion ability of cells. In conclusion, our data demonstrate that TGF-β1 induces EMT by the transactivation of EGF signaling through HA/CD44 in lung and breast cancer cells.

No MeSH data available.


Related in: MedlinePlus