Efficacy of Wnt-1 monoclonal antibody in sarcoma cells.
BACKGROUND
Sarcomas are one of the most refractory diseases among malignant tumors. More effective therapies based on an increased understanding of the molecular biology of sarcomas are needed as current forms of therapy remain inadequate. Recently, it has been reported that Wnt-1/beta-catenin signaling inhibits apoptosis in several cancers. In this study, we investigated the efficacy of a monoclonal anti-Wnt-1 antibody in sarcoma cells.


METHODS
We treated cell lines A-204, SJSA-1, and fresh primary cultures of lung metastasis of sarcoma with a monoclonal anti-Wnt-1 antibody. Wnt-1 siRNA treatment was carried out in A-204. We assessed cell death using Crystal Violet staining. Apoptosis induction was estimated by flow cytometry analysis (Annexin V and PI staining). Cell signaling changes were determined by western blotting analysis.


RESULTS
We detected Wnt-1 expression in all tissue samples and cell lines. Significant apoptosis induction was found in monoclonal anti-Wnt-1 antibody treated cells compared to control monoclonal antibody treated cells (p < 0.02). Similarly, we observed increased apoptosis in Wnt-1 siRNA treated cells. Blockade of Wnt-1 signaling in both experiments was confirmed by analyzing intracellular levels of Dishevelled-3 and of cytosolic beta-catenin. Furthermore, the monoclonal anti-Wnt-1 antibody also induced cell death in fresh primary cultures of metastatic sarcoma in which Wnt-1 signaling was active.


CONCLUSIONS
Our results indicate that Wnt-1 blockade by either monoclonal antibody or siRNA induces cell death in sarcoma cells. These data suggest that Wnt-1 may be a novel therapeutic target for the treatment of a subset of sarcoma cells in which Wnt-1/beta-catenin signaling is active.
Mikami
Iwao
I
Department of Surgery, Comprehensive Cancer Center, University of California, San Francisco, CA 94115, USA. imikami@cc.ucsf.edu
You
Liang
L
He
Biao
B
Xu
Zhidong
Z
Batra
Sonny
S
Lee
Amie Y
AY
Mazieres
Julien
J
Reguart
Noemi
N
Uematsu
Kazutsugu
K
Koizumi
Kiyoshi
K
Jablons
David M
DM
D048868:Adaptor Proteins, Signal Transducing; D017304:Annexin A5 / Q000494:pharmacology; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000627:therapeutic use*; D017209:Apoptosis; D015153:Blotting, Western; D045744:Cell Line, Tumor; D000072261:Dishevelled Proteins; D005434:Flow Cytometry; D005456:Fluorescent Dyes / Q000494:pharmacology; D005840:Gentian Violet / Q000494:pharmacology; D006801:Humans; D008175:Lung Neoplasms / Q000276:immunology / Q000556:secondary* / Q000628:therapy*; D009362:Neoplasm Metastasis; D010750:Phosphoproteins; D011419:Propidium / Q000494:pharmacology; D011506:Proteins / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D012509:Sarcoma / Q000196:embryology / Q000276:immunology / Q000473:pathology / Q000628:therapy*; D015398:Signal Transduction; D014407:Tumor Cells, Cultured; D051155:Wnt1 Protein / Q000737:chemistry / Q000276:immunology* / Q000502:physiology; D051176:beta Catenin / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D017304:Annexin A5; D000911:Antibodies, Monoclonal; C000606584:DVL3 protein, human; D000072261:Dishevelled Proteins; D005456:Fluorescent Dyes; D010750:Phosphoproteins; D011506:Proteins; D034741:RNA, Small Interfering; D051155:Wnt1 Protein; D051176:beta Catenin; D011419:Propidium; D005840:Gentian Violet