PKN3 is the major regulator of angiogenesis and tumor metastasis in mice.

Hideyuki Mukai,Reiko Sugiura,Ryosuke Satoh,Yasunori Kanaho,Mona Mehruba,Tsunaki Hongu,Koji Kubouchi,Go Shioi,Aiko Muramatsu,Sho Tsujimoto,Shozo Nishida,Sally Danno,Masanobu Tsubaki,Rana Mashud

doi:10.1038/srep18979

Abstract

PKN, a conserved family member related to PKC, was the first protein kinase identified as a target of the small GTPase Rho. PKN is involved in various functions including cytoskeletal arrangement and cell adhesion. Furthermore, the enrichment of PKN3 mRNA in some cancer cell lines as well as its requirement in malignant prostate cell growth suggested its involvement in oncogenesis. Despite intensive research efforts, physiological as well as pathological roles of PKN3 in vivo remain elusive. Here, we generated mice with a targeted deletion of PKN3. The PKN3 knockout (KO) mice are viable and develop normally. However, the absence of PKN3 had an impact on angiogenesis as evidenced by marked suppressions of micro-vessel sprouting in ex vivo aortic ring assay and in vivo corneal pocket assay. Furthermore, the PKN3 KO mice exhibited an impaired lung metastasis of melanoma cells when administered from the tail vein. Importantly, PKN3 knock-down by small interfering RNA (siRNA) induced a glycosylation defect of cell-surface glycoproteins, including ICAM-1, integrin β1 and integrin α5 in HUVECs. Our data provide the first in vivo genetic demonstration that PKN3 plays critical roles in angiogenesis and tumor metastasis, and that defective maturation of cell surface glycoproteins might underlie these phenotypes.

Highlights

During the morphogenetic process of dorsal closure of the embryo, a developmental process in which Rho and Rac GTPases have been directly implicated[26]
This paper represents the first description on the role of PKN3 in angiogenesis and tumor metastasis by establishing PKN3 KO mice
We demonstrated that genetic ablation of PKN3 inhibits angiogenesis ex vivo and in vivo and gives resistance to lung metastasis after tail vein injection of melanoma

Summary

Introduction

During the morphogenetic process of dorsal closure of the embryo, a developmental process in which Rho and Rac GTPases have been directly implicated[26]. With regard to the organismal study for each mammalian PKN isoform, only one KO mouse line of PKN1 has been generated, and only abnormal survival and selection of B-cells in secondary lymphoid organs have been reported so far in these mice[27], without referring to the relationship of PKN1 with cell migration or with Rho GTPases. Fibroblastic cells derived from PKN3 KO mice have lower cell migration activity, and PKN3 KO mice showed poor growth factor-induced angiogenesis and suppression of lung metastasis of B16 melanoma cells injected through tail vein. The relationship between the suppression of growth factor-induced angiogenesis and tumor metastasis has not been clarified, but the PKN3 KO mouse experiment clearly revealed that the host PKN3 is crucial for tumor metastasis. We discuss the potential relationship between PKN3 and the small GTPase RhoC based on the phenotype induced by deficiency of each molecule

Methods

Results

Conclusion