Upregulation of dual-specificity phosphatase-26 is required for transforming growth factor β1(TGFβ1)-induced Epithelial-mesenchymal transition in A549 and PANC1 cells

Abstract

Background: Transforming Growth Factor β (TGFβ) proteins are potent inducers of the epithelialmesenchymal transition (EMT) in tumor cells. Although mitogen-activated protein kinase (MAPK) family has been shown to be involved in TGFβ-induced EMT, role of Dual Speci city Phosphatases (DUSP), key regulators of MAPK activity, in TGFβ-induced EMT is largely unkonwn.Methods and Results: Real-time qPCR analyses were performed to determine the effect of TGFβ1 on expression of EMT genes and DUSP proteins in the non-small cell lung cancer model A549 and pancreatic adenocarcinoma model PANC1 cells. Western blot analyses were conducted to study the changes in protein levels of EMT proteins and select DUSP proteins, as well as phosphorylations of MAPK proteins upon TGFβ1 stimulation. Small interfering RNA (siRNA) was utilized to reduce expressions of DUSP genes. We observed that the EMT phenotype coincided with increases in phosphorylations of the MAPK proteins ERK1/2, p38MAPK, and JNK upon TGFβ1 stimulation. Real-time qPCR analysis showed increases in DUSP15 and DUSP26 mRNA levels and Western blot analysis con rmed the increase in DUSP26 protein levels in both A549 and PANC1 cells treated with TGFβ1 relative to control. Silencing of DUSP26 expression by siRNA markedly suppressed the effect of TGFβ1 on E-cadherin and mesenchymal genes in the cells.Conclusions: Data provided suggest that TGFβ1 modulates the expression of DUSP genes and that upregulation of DUSP26 may be required for TGFβ1-promoted EMT in A549 and PANC1 cells. Further studies should be carried out to elucidate the requirement of individual DUSPs in TGFβ1-associated EMT in tumor cells.

Expression of dual-specificity phosphatases in TGFß1-induced EMT in SKOV3 cells

“…Moreover, DUSP4/13 coexpression partially inhibited TGFβ1-promoted migration, invasion, and chemoresistance in A549 cells [ 26 ]. In TGF-induced pancreatic adenocarcinoma (PANC-1) cells, silencing of DUSP26 expression by siRNA markedly suppressed the effect of TGFβ1 on E-cadherin and mesenchymal genes in the cells [ 27 ]. Our study reveals that all the known typical and tested atypical DUSPs are expressed at various levels in the ovarian cancer cell line SKOV3 and TGFβ1 treatment leads to marked changes in the expression of several DUSPs.…”

Dual-Specificity Phosphatases in Regulation of Tumor-Associated Macrophage Activity

“…↓ ovarian cancer, neuroblastoma, medulloblastoma and glioblastoma [146] ↑ thyroid carcinoma [147] ↑ for TGFβ1-promoted EMT in pancreatic, lung cancers cell lines [148] positive correlation with DFS in neuroblastoma [149] Thus, the presence of DUSPs in tumors was demonstrated in studies to correlate with a poor or good outcome. However, these studies are limited to the bulk analysis of tumor tissues and it is difficult to determine whether tumor or immune cells contribute to changes in DUSP expression in the tissue.…”