Gab2 facilitates epithelial-to-mesenchymal transition via the MEK/ERK/MMP signaling in colorectal cancer

Abstract

BackgroundGrb2-associated binder 2 (Gab2), a scaffolding adaptor protein, has recently been implicated in cancer progression. However, the role of Gab2 in the progression and metastasis of colorectal cancer (CRC) remains unclear.MethodsGab2 expression was assessed in CRC patient specimens as well as in CRC cell lines. Recombinant lentivirus vector containing Gab2 gene and its small interfering RNAs were constructed and introduced into CRC cells. Cell migration and invasion ability were evaluated by transwell assays in vitro, and in vivo metastasis was performed on nude mice model. Moreover, the expression of Gab2 and epithelial-to-mesenchymal transition (EMT)-associated proteins (E-cadherin and vimentin) were assessed by western blot and qRT-PCR in CRC cells to evaluate the correlation between Gab2 and EMT. Finally, we evaluated the impact of Gab2 on the activation of its downstream signaling effectors, and furthermore the effects of these pathways on Gab2 induced-EMT were also detected.ResultsWe confirmed that increased Gab2 expression correlated with higher tumor node metastasis stage and highly invasive CRC cell lines. Ectopic expression of Gab2 promoted metastasis of CRC cells, whereas silencing of Gab2 resulted in inhibited metastasis both in vitro and in vivo. Overexpression of Gab2 in CRC cells induced EMT, whereas knockdown of Gab2 had the opposite effect. Furthermore, upregulation of Gab2 expression obviously stimulated the activation of extracellular signal-regulated kinase-1/2 (ERK1/2), and increased the expression of matrix metalloproteinase-7 (MMP7) and matrix metalloproteinase-9 (MMP9) in CRC cells. Conversely, downregulation of Gab2 expression significantly decreased the activation of ERK1/2, and inhibited MMP7 and MMP9 expression. U0126, an inhibitor of mitogen-activated protein kinase (MEK), can reverse the effects of Gab2 on EMT.ConclusionsOur work highlights that Gab2 induces EMT through the MEK/ERK/MMP pathway, which in turn promotes intestinal tumor metastasis.Electronic supplementary materialThe online version of this article (doi:10.1186/s13046-015-0280-0) contains supplementary material, which is available to authorized users.

HspB5 correlates with poor prognosis in colorectal cancer and prompts epithelial-mesenchymal transition through ERK signaling

“…Bewilderingly, the ERK, but not PI3K and p38 signaling pathways may be crucially involved in the invasion, proliferation and EMT induced by HspB5 over-expression in Lovo Cells. One plausible explanation is that the functions of PI3K/Akt, ERK and Raf/MAPK in EMT might depend on the different cell types[ 33 ].…”

Combined application of anti-VEGF and anti-EGFR attenuates the growth and angiogenesis of colorectal cancer mainly through suppressing AKT and ERK signaling in mice model

“…Invasion assays were performed as reported [ 20 ]. Transwell invasion assays were performed in Corning Matrigel invasion chamber containing an 8 μm pore-size polycarbonate membrane with a uniform layer of BD Matrigel basement membrane matrix (BD Biosciences, USA).…”

“…Immunohistochemical assay for paraffin-embedded tissues were performed as reported [ 19 , 20 ]. The evaluation principle was quantified based on the immunoreactive score (IRS), which was calculated as a product of staining intensity (SI) and percentage of positive cells (PP).…”

CCR4 promotes metastasis via ERK/NF-κB/MMP13 pathway and acts downstream of TNF-α in colorectal cancer

“…When treated with small chemical inhibitors against key factors of pathways (U0126 and LY294002), we found that MMP13 expression was inhibited by the blockaded of ERK signaling in tumor cells. Recently, ERK/MMP pathway was shown to facilitate epithelial-to-mesenchymal transition in colorectal cancer [29]. The study by Liang et al [30] indicated that interleukin-1-induced MMP9 expression required the activation of ERK signaling.…”