A novel inhibitor, 16-hydroxy-cleroda-3,13-dien-16,15-olide, blocks the autophosphorylation site of focal adhesion kinase (Y397) by molecular docking.

BACKGROUND

Focal adhesion kinase (FAK) is a nonreceptor protein tyrosine plays an important role in a number of cell signaling pathways, including cell migration, proliferation, and cell survival. This study was aimed to identify novel and specific inhibitors from natural compounds via molecular docking of FAK (Y397).

METHODS

The 3D structure of FAK (PDB ID: 2AL6) was used for docking 109 natural compounds. Based on high affinity and energy interaction, four of ten candidate compounds, 16-hydroxy-cleroda-3,13-dien-16,15-olide (HCD), curcumin, quercetin, and catechin hydrate, were hit, and the inhibitory activity against FAK was validated in these compounds in C6 glioma and N18 neuroblastoma cell lines.

RESULTS

HCD showed a potential effect on cell viability by MTT assay and cell arrest in the G0-G1 phase, and a TUNEL assay confirmed further apoptosis. Treatment with HCD decreased anti-apoptotic proteins and increased pro-apoptotic proteins. Atomic force microscopy data depicted that the formation of filopodia on the intracellular surface decreased in treated cells compared with the control. Zymography showed that HCD inhibited the activity of MMP-2 and MMP-9. The protein levels of FAK, pFAK, Rac1 and Cdc42, which are the key regulators for the formation of filopodia, were decreased. Additionally, HCD regulated the expression of epithelial mesenchymal transition proteins.

CONCLUSIONS

HCD effectively interacted at the autophosphorylation site of FAK and interaction analysis indicated an H-bond with the Arg 86 and Arg 125 residues.

GENERAL SIGNIFICANCE

This study suggests that HCD could be a potential inhibitor of FAK and could be used for anti-tumorigenesis and anti-metastasis treatments.