P68.10 PFN1 Induces Tumor Metastasis Through Promoting Secretion of Microvesicles By ROCK I/p-MLC Pathway in Non-Small Cell Lung Cancer

Abstract

Profilin1(PFN1) plays confusing roles in metastasis of different cancers, here we explored the roles of PFN1 in metastasis of non-small cell lung cancer (NSCLC). Considering that PFN1 is an important mediator of membrane trafficking and microvesicles(MVs) have already been proved closely associated with tumor metastasis, we further explored relationship of PFN1 and MVs in NSCLC metastasis and the underlying mechanisms. We first detect PFN1 and p-MLC expression in tissue microarray. Then we extracted MVs of NSCLC patients’ serums by continuous differential centrifugation, quantified MVs by WB, electron microscopy and spectral flow cytometry. And PFN1 was overexpression/ knockdown to study the effect of MVs secretion and cell migration. Protein interaction was tested by CO-IP. ROCK kinase assay was used to detect ROCK kinase activity. For in vivo experiment, intracardiac injection of H1299 cell lines were used to establish metastatic tumor model for in vivo assay. PFN1 were highly expressed in late stage NSCLC tissues, and the expression of PFN1 is positively correlated with p-MLC in IHC. Overexpression of PFN1 promotes MVs secretion and metastasis in vitro. Further investigation found that PFN1 could interact with ROCK I and affect the activity of ROCK I to phosphorylate MLC, which could regulate the secretion of MVs. Inhibition of ROCK I activity by Y27632 partially reverse PFN1’ s promotion of MVs secretion and NSCLC metastasis in vivo and in vitro. PFN1 affects NSCLC metastasis via promoting MVs’ secretion, which provided us a new insight into PFN1’s roles in cancer metastasis and a new target of therapy in NSCLC metastasis.