Protein C inhibitor inhibits breast cancer cell growth, metastasis and angiogenesis independently of its protease inhibitory activity.
Protein C inhibitor (PCI) regulates the anticoagulant protein C pathway and also inhibits urinary plasminogen activator (uPA), a mediator of tumor cell invasion. In the present study, we evaluated the effect of human PCI and its inactive derivatives on tumor growth and metastasis of human breast cancer (MDA-231) cells, and on angiogenesis in vivo. The invasiveness of MDA-231 cells was inhibited by recombinant intact PCI, but not by reactive site-modified PCI (R354APCI) or by the N-terminal fragment of protease-cleaved PCI (NTPCI). The in vitro invasiveness of MDA-231 cells expressing intact PCI (MDA-PCI) was significantly decreased as compared to MDA-231 cells expressing R354APCI (MDA-R354APCI) or NTPCI (MDA-NTPCI). Further, in vivo growth and metastatic potential of MDA-PCI, MDA-R354APCI and MDA-NTPCI cells in severe combined immunodeficient (SCID) mice were significantly decreased as compared to MDA-Mock cells. Angiogenesis was also significantly decreased in Matrigel implant containing MDA-PCI, MDA-R354APCI or MDA-NTPCI cells as compared to that containing MDA-Mock cells. In vivo angiogenesis in rat cornea and in vitro tube formation were also inhibited by recombinant intact PCI, R354APCI and NTPCI. Furthermore, the anti-angiogenic activity of PCI was strong as cleaved antithrombin (AT), and slightly stronger than that of plasminogen activator inhibitor (PAI)-1 and pigment epithelium-derived factor (PEDF). Overall, this study showed that, in addition to a reactive site-dependent mechanism, PCI may also regulate tumor growth and metastasis independently of its protease inhibitory activity by inhibiting angiogenesis.
Asanuma
Kunihiro
K
Department of Molecular Pathobiology, Mie University Graduate School of Medicine, Tsu-city, Mie, Japan.
Yoshikawa
Tomoaki
T
Hayashi
Tatsuya
T
Akita
Nobuyuki
N
Nakagawa
Norimi
N
Hamada
Yasuhiko
Y
Nishioka
Junji
J
Kamada
Haruhiko
H
Gabazza
Esteban C
EC
Ido
Masaru
M
Uchida
Atsumasa
A
Suzuki
Koji
K
D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000098:blood supply / Q000473:pathology*; D002455:Cell Division / Q000502:physiology*; D045744:Cell Line, Tumor; D017931:DNA Primers; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D051379:Mice; D016513:Mice, SCID; D009362:Neoplasm Metastasis; D009389:Neovascularization, Pathologic; D018046:Protein C Inhibitor / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction
D017931:DNA Primers; D018046:Protein C Inhibitor