The functionalized human serine protease granzyme B/VEGF₁₂₁ targets tumor vasculature and ablates tumor growth.
نویسندگان
چکیده
The serine protease granzyme B (GrB) induces apoptosis through both caspase-dependent and -independent multiple-cascade mechanisms. VEGF₁₂₁ binds to both VEGF receptor (VEGFR)-1 and VEGFR-2 receptors. We engineered a unique GrB/VEGF₁₂₁ fusion protein and characterized its properties in vitro and in vivo. Endothelial and tumor cell lines showed varying levels of sensitivity to GrB/VEGF₁₂₁ that correlated closely to total VEGFR-2 expression. GrB/VEGF₁₂₁ localized efficiently into VEGFR-2-expressing cells, whereas the internalization into VEGFR-1-expressing cells was significantly reduced. Treatment of VEGFR-2(+) cells caused mitochondrial depolarization in 48% of cells by 48 hours. Exposure to GrB/VEGF₁₂₁ induced apoptosis in VEGFR-2(+), but not in VEGFR-1(+), cells and rapid caspase activation was observed that could not be inhibited by treatment with a pan-caspase inhibitor. In vivo, GrB/VEGF₁₂₁ localized in perivascular tumor areas adjacent to microvessels and in other areas in the tumor less well vascularized, whereas free GrB did not specifically localize to tumor tissue. Administration (intravenous) of GrB/VEGF₁₂₁ to mice at doses up to 40 mg/kg showed no toxicity. Treatment of mice bearing established PC-3 tumor xenografts with GrB/VEGF₁₂₁ showed significant antitumor effect versus treatment with GrB or saline. Treatment with GrB/VEGF₁₂₁ at 27 mg/kg resulted in the regression of four of five tumors in this group. Tumors showed a two-fold lower Ki-67-labeling index compared with controls. Our results show that targeted delivery of GrB to tumor vascular endothelial cells or to tumor cells activates apoptotic cascades and this completely human construct may have significant therapeutic potential.
منابع مشابه
The Functionalized Human Serine Protease Granzyme B/VEGF121 Targets Tumor Vasculature and Ablates Tumor Growth Running title: Granzyme B/VEGF121 blocks growth of solid tumors
متن کامل
The Functionalized Human Serine Protease Granzyme B/VEGF121 Targets Tumor Vasculature and Ablates Tumor Growth
The serineprotease granzymeB (GrB) induces apoptosis throughboth caspase-dependent and -independent multiple-cascade mechanisms. VEGF121 binds to both VEGF receptor (VEGFR)-1 and VEGFR-2 receptors. We engineered a unique GrB/VEGF121 fusion protein and characterized its properties in vitro and in vivo. Endothelial and tumor cell lines showed varying levels of sensitivity to GrB/VEGF121 that corr...
متن کاملGranzyme M expressed by tumor cells promotes chemoresistance and EMT in vitro and metastasis in vivo associated with STAT3 activation
Granzyme M is a serine protease known to be often expressed by natural killer cells and induce target cells apoptosis in combination with perforin. However, we detected granzyme M expression in murine and human cancer cell lines and human tumor samples in our study. Granzyme M increased chemoresistance, colony-formation, cytokine secretion and invasiveness in vitro. Most importantly, granzyme M...
متن کاملTargeting of Tumor Neovasculature with GrB/VEGF121, a Novel Cytotoxic Fusion Protein
Angiogenesis is a critical process in numerous diseases, and intervention in neovascularization has therapeutic value in several disease settings, including ocular diseases, arthritis, and in tumor progression and metastatic spread. Various vascular targeting agents have been developed, including those that inhibit growth factor receptor tyrosine kinases, blocking antibodies that interfere with...
متن کاملMechanistic studies of a novel human fusion toxin composed of vascular endothelial growth factor (VEGF)121 and the serine protease granzyme B: directed apoptotic events in vascular endothelial cells.
The serine protease granzyme B (GrB; 25 kDa) is capable of inducing apoptosis through both caspase-dependent and caspase-independent mechanisms. We designed a novel vascular-targeting fusion construct designated as GrB/vascular endothelial growth factor (VEGF)121, which is composed of a non-heparin-binding isoform of VEGF and the proapoptotic pathway enzyme GrB fused via a short, flexible tethe...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Molecular cancer therapeutics
دوره 12 10 شماره
صفحات -
تاریخ انتشار 2013