Enzastaurin inhibits invasion and metastasis in lung cancer by diverse molecules.

BACKGROUND

Enzastaurin (Enz) is a serine/threonine kinase inhibitor blocking protein kinase C (PKC)beta/AKT pathway. However, an ability of this compound to inhibit cancer invasion and metastasis is not yet clearly elucidated.

METHODS

The ability of Enz to inhibit invasion and metastasis, and to target molecules was investigated in non-small cell lung cancer (NSCLC) by RT-PCR validated microarray, Matrigel, and in vivo chorionallantoic membrane (CAM) assays.

RESULTS

Enzastaurin significantly reduced migration, invasion, and in vivo metastasis to lungs and liver (CAM assay) of diverse NSCLC cell lines. Genes promoting cancer progression (u-PAR, VEGFC, and HIF1alpha) and tumour suppression (VHL, RASSF1, and FHIT) of NSCLC were significantly (P<0.05) down- or upregulated after Enz treatment in H460, A549, and H1299 cells, respectively. Luciferase/chromatin immunoprecipitation analysis showed that Enz transcriptionally controls urokinase-type plasminogen activator receptor (u-PAR) expression by promoter inhibition through Sp1, Sp3, and c-Jun(AP-1). Moreover, siRNA knockdown of u-PAR re-sensitised Enz-resistant cells and induced apoptosis, suggesting u-PAR as a marker of Enz resistance.

CONCLUSION

This study shows that Enz inhibits migration, invasion, and in vivo metastasis by targeting u-PAR, besides further targeting progression-related and tumour-suppressor genes in NSCLC. Together with u-PAR being a novel putative marker of Enz response, these data encourage molecularly tailored clinical studies on Enz in NSCLC therapy.