Background: In cancer cells, re-activation of Epithelial-Mesenchymal Transition (EMT) program
through Discoidin Domain Receptor1 (DDR1) leads to metastasis. DDR1-targeted therapy with siRNA might be
a promising strategy for EMT inhibition. Therefore, the aim of this study was to investigate the effect of DDR1
knockdown in the EMT, migration, and apoptosis of prostate cancer cells. For this purpose, the expression of
DDR1 was down regulated by the siRNA approach in LNcap-FGC and DU-145 prostate cancer cells.
Methods: Immunocytochemistry was carried out for the assessment of EMT. E-cadherin, N-cadherin, Bax,
Bcl2, and the phosphorylation level of Proline-rich tyrosine kinase 2 (Pyk2) and Map Kinase Kinase 7 (MKK7)
was determined using the western blot. Wound healing assay was used to evaluate cell migration. Flow cytometry
was employed to determine the apoptosis rate in siRNA-transfected cancer cells.
Results: Our findings showed that the stimulation of DDR1 with collagen-I caused increased phosphorylation of
Pyk2 and MKK7 signaling molecules that led to the induction of EMT and migration in DU-145 and LNcap-
FGC cells. In contrast, DDR1 knockdown led to significant attenuation of EMT, migration, and phosphorylation
levels of Pyk2 and MKK7. Moreover, DDR1 knockdown via induction of Bax expression and suppression of
Bcl-2 expression induces apoptosis.
Conclusion: Collectively, our results indicate that the DDR1 targeting with siRNA may be beneficial for the
inhibition of EMT and the induction of apoptosis in prostate cancer.