Limits...
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

shRNA targeting CD44 (shCD44) blocks the activation of the AKT and ERK pathways and causes the reversal of epithelial-mesenchymal transition (EMT). (A) Western blot analysis revealed that the CD44 protein levels and epidermal growth factor receptor (EGFR) expression were altered following stimulation with transforming growth factor-β1 (TGF-β1) or TGF-β1 plus shRNA. β-actin was used as a loading control. (B and C) 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 shCD44. β-actin was used as a loading control.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4494581&req=5

f6-ijmm-36-01-0113: shRNA targeting CD44 (shCD44) blocks the activation of the AKT and ERK pathways and causes the reversal of epithelial-mesenchymal transition (EMT). (A) Western blot analysis revealed that the CD44 protein levels and epidermal growth factor receptor (EGFR) expression were altered following stimulation with transforming growth factor-β1 (TGF-β1) or TGF-β1 plus shRNA. β-actin was used as a loading control. (B and C) 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 shCD44. β-actin was used as a loading control.

Mentions: We then examined whether the disruption of CD44 expression effectively suppresses the expression of EGFR. Transfection of the cells with shRNA-CD44 resulted in a decrease in CD44 and EGFR expression compared to the controls and the TGF-β1-treated group (Fig. 6A). We found that the knockdown of CD44 also caused a marked decrease in the levels of p-ERK and p-AKT, whereas it had no effect on the levels of p-Smad (Fig. 6B), demonstrating the effects of CD44 on TGF-β1-induced EGF/EGFR signaling. Alterations in the expression of EMT-associated proteins indicated that interference with the expression of CD44 reversed EMT (Fig. 6C). Transfection of the cells with shRNA-CD44 increased E-cadherin expression and decreased N-cadherin, Snail, Twist and ZEB1 expression. Cell migration/invasion assays revealed that transfection with shRNA-CD44 partially suppressed cell migration and invasion during the EMT process induced by TGF-β1 (Fig. 7).


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)

shRNA targeting CD44 (shCD44) blocks the activation of the AKT and ERK pathways and causes the reversal of epithelial-mesenchymal transition (EMT). (A) Western blot analysis revealed that the CD44 protein levels and epidermal growth factor receptor (EGFR) expression were altered following stimulation with transforming growth factor-β1 (TGF-β1) or TGF-β1 plus shRNA. β-actin was used as a loading control. (B and C) 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 shCD44. β-actin was used as a loading control.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f6-ijmm-36-01-0113: shRNA targeting CD44 (shCD44) blocks the activation of the AKT and ERK pathways and causes the reversal of epithelial-mesenchymal transition (EMT). (A) Western blot analysis revealed that the CD44 protein levels and epidermal growth factor receptor (EGFR) expression were altered following stimulation with transforming growth factor-β1 (TGF-β1) or TGF-β1 plus shRNA. β-actin was used as a loading control. (B and C) 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 shCD44. β-actin was used as a loading control.
Mentions: We then examined whether the disruption of CD44 expression effectively suppresses the expression of EGFR. Transfection of the cells with shRNA-CD44 resulted in a decrease in CD44 and EGFR expression compared to the controls and the TGF-β1-treated group (Fig. 6A). We found that the knockdown of CD44 also caused a marked decrease in the levels of p-ERK and p-AKT, whereas it had no effect on the levels of p-Smad (Fig. 6B), demonstrating the effects of CD44 on TGF-β1-induced EGF/EGFR signaling. Alterations in the expression of EMT-associated proteins indicated that interference with the expression of CD44 reversed EMT (Fig. 6C). Transfection of the cells with shRNA-CD44 increased E-cadherin expression and decreased N-cadherin, Snail, Twist and ZEB1 expression. Cell migration/invasion assays revealed that transfection with shRNA-CD44 partially suppressed cell migration and invasion during the EMT process induced by TGF-β1 (Fig. 7).

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