YB-1 expression promotes epithelial-to-mesenchymal transition in prostate cancer that is inhibited by a small molecule fisetin.
Epithelial-to-mesenchymal transition (EMT) plays an important role in prostate cancer (PCa) metastasis. The transcription/translation regulatory Y-box binding protein-1 (YB-1) is known to be associated with cancer metastasis. We observed that YB-1 expression increased with tumor grade and showed an inverse relationship with E-cadherin in a human PCa tissue array. Forced YB-1 expression induced a mesenchymal morphology that was associated with down regulation of epithelial markers. Silencing of YB-1 reversed mesenchymal features and decreased cell proliferation, migration and invasion in PCa cells. YB-1 is activated directly via Akt mediated phosphorylation at Ser102 within the cold shock domain (CSD). We next identified fisetin as an inhibitor of YB-1 activation. Computational docking and molecular dynamics suggested that fisetin binds on the residues from β1 - β4 strands of CSD, hindering Akt's interaction with YB-1. Calculated free binding energy ranged from -11.9845 to -9.6273 kcal/mol. Plasmon Surface Resonance studies showed that fisetin binds to YB-1 with an affinity of approximately 35 µM, with both slow association and dissociation. Fisetin also inhibited EGF induced YB-1 phosphorylation and markers of EMT both in vitro and in vivo. Collectively our data suggest that YB-1 induces EMT in PCa and identify fisetin as an inhibitor of its activation.
Department of Dermatology, School of Medicine and Public Health, University of Wisconsin, Madison, WI.
Mohammad Imran
MI
Khan
Vaqar Mustafa
VM
Adhami
Rahul Kumar
RK
Lall
Mario
M
Sechi
Dinesh C
DC
Joshi
Omar M
OM
Haidar
Deeba Nadeem
DN
Syed
Imtiaz Ahmad
IA
Siddiqui
Shing-Yan
SY
Chiu
Hasan
H
Mukhtar
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D002448:Cell Adhesion / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects*; D005419:Flavonoids / Q000494:pharmacology*; D044948:Flavonols; D005455:Fluorescent Antibody Technique; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D051379:Mice; D008819:Mice, Nude; D060787:Neoplasm Grading; D010766:Phosphorylation / Q000187:drug effects; D011467:Prostate / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D046888:Tissue Array Analysis; D014407:Tumor Cells, Cultured; D023041:Xenograft Model Antitumor Assays; D051840:Y-Box-Binding Protein 1 / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism*
D005419:Flavonoids; D044948:Flavonols; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D051840:Y-Box-Binding Protein 1; C070856:YBX1 protein, human; C017875:fisetin