To explore the effect of SP600125, a c-Jun N-terminal kinases (JNK) inhibitor, on epithelial-mesenchymal transition (EMT) in retinal pigment epithelial (RPE) cell caused by transforming growth factor-beta 2 (TGF-β2).

Human RPE cell line (ARPE-19) cells were treated with TGF-β2 and JNK inhibitor SP600125 in vitro. Cellular viability, migration and proliferation in ARPE-19 cells were examined by cell counting kit-8 (CCK-8) assay, wound scratch, and bromodeoxyuridine (BrdU) staining assay, respectively. Transforming growth factor-beta receptor 2 (TGF-βR2), Smad2/3, JNK, c-Jun, alpha-smooth muscle actin (α-SMA), N-cadherin, and vimentin proteins were analyzed by immunoblotting. Moreover, TGF-βR2 was detected by immunofluorescence assay.

TGF-β2 significantly enhanced viability, migration, and proliferation in ARPE‑19 cells, induced phosphorylation of TGF-βR2, Smad2/3, JNK, and c‑Jun, and upregulated α‑SMA, N‑cadherin, and vimentin expression. SP600125 inhibited these cellular processes and reduced the expression/phosphorylation of the above proteins; notably, it blocked TGF-β2‑induced effects, including cell viability, migration, proliferation, phosphorylation of TGF-βR2, Smad2/3, JNK, and c‑Jun, as well as upregulation of α‑SMA, N‑cadherin, and vimentin.

JNK inhibitor SP600125 suppresses TGF-β2-induced the increases in cell viability, migration, proliferation, and EMT in RPE cells via the TGF-βR2/Smad2/3 and JNK/c-Jun signaling pathways.

To explore the effect of epidermal growth factor receptor (EGFR) inhibition by erlotinib and EGFR siRNA on epidermal growth factor (EGF)-induced activation of retinal pigment epithelium (RPE) cells.

Human RPE cell line (ARPE-19 cells) was activated by 100 ng/mL EGF. Erlotinib and EGFR siRNA were used to intervene EGF treatment. Cellular viability, proliferation, and migration were detected by methyl thiazolyl tetrazolium (MTT) assay, bromodeoxyuridine (BrdU) staining assay and wound healing assay, respectively. EGFR/protein kinase B (AKT) pathway proteins and N-cadherin, α-smooth muscle actin (α-SMA), and vimentin were tested by Western blot assay. EGFR was also determined by immunofluorescence staining.

EGF treatment for 24h induced a significant increase of ARPE-19 cells’ viability, proliferation and migration, phosphorylation of EGFR/AKT proteins, and decreased total EGFR expression. Erlotinib suppressed ARPE-19 cells’ viability, proliferation and migration through down regulating total EGFR and AKT protein expressions. Erlotinib also inhibited EGF-induced an increase of proliferative and migrative ability in ARPE-19 cells and clearly suppressed EGF-induced EGFR/AKT proteins phosphorylation and decreased expression of N-cadherin, α-SMA, and vimentin proteins. Similarly, EGFR inhibition by EGFR siRNA significantly affected EGF-induced an increase of cell proliferation, viability, and migration, phosphorylation of EGFR/AKT proteins, and up-regulation of N-cadherin, α-SMA, and vimentin proteins.

Erlotinib and EGFR-knockdown suppress EGF-induced cell viability, proliferation, and migration via EGFR/AKT pathway in RPE cells. EGFR inhibition may be a possible therapeutic approach for proliferative vitreoretinopathy (PVR).

To explore the effects of hepatocyte growth factor (HGF) on retinal pigment epithelium (RPE) cell behaviors.

The human adult retinal pigment epithelial cell line-19 (ARPE-19) were treated by HGF or mesenchymal-epithelial transition factor (MET) inhibitor SU11274 in vitro. Cell viability was detected by a Cell Counting Kit-8 assay. Cell proliferation and motility was detected by a bromodeoxyuridine incorporation assay and a wound healing assay, respectively. The expression levels of MET, phosphorylated MET, protein kinase B (AKT), and phosphorylated AKT proteins were determined by Western blot assay. The MET and phosphorylated MET proteins were also determined by immunofluorescence assay.

HGF increased ARPE-19 cells’ viability, proliferation and migration, and induced an increase of phosphorylated MET and phosphorylated AKT proteins. SU11274 significantly reduced cell viability, proliferation, and migration and decreased the expression of MET and AKT proteins. SU11274 suppressed HGF-induced increase of viability, proliferation, and migration in ARPE-19 cells. Additionally, SU11274 also blocked HGF-induced phosphorylation of MET and AKT proteins.

HGF enhances cellular viability, proliferation, and migration in RPE cells through the MET/AKT signaling pathway, whereas this enhancement is suppressed by the MET inhibitor SU11274. HGF-induced MET/AKT signaling might be a vital contributor of RPE cells survival.