Endosialin protein expression and therapeutic target potential in human solid tumors: sarcoma versus carcinoma.
OBJECTIVE
Endosialin/CD248/tumor endothelial marker 1 is expressed in stromal cells, endothelial cells, and pericytes in various tumors; however, few studies have focused on expression in malignant cells.


METHODS
We studied expression of endosialin in clinical specimens, cell culture, and animal models and designed an anti-endosialin therapeutic prototype.


RESULTS
Fifty human tumor cell lines and 6 normal cell types in culture were assayed by reverse transcription-PCR and/or flow cytometry for endosialin. Cell surface protein was found on 7 sarcoma lines, 1 neuroblastoma, and 4 normal cell types in culture. A fully human anti-endosialin antibody bound to human A-673 Ewing's sarcoma cells and SK-N-AS neuroblastoma cells but not HT-1080 cells. Exposure of cells to an anti-human IgG conjugated to saporin resulted in growth inhibition only of endosialin-expressing cells. Endosialin expression was assessed by immunohistochemistry in 250 clinical specimens of human cancer including 20 cancer subtypes. Endosialin is frequently found in human cancers. Endosialin expression is mainly a perivascular feature in carcinomas, with some expression in stromal cells. In sarcomas, endosialin is expressed by malignant cells, perivascular cells, and stromal cells. Development and characterization of experimental models for studying endosialin biology in sarcomas and evaluating anti-endosialin therapies is presented.


CONCLUSIONS
Findings suggest that an anti-endosialin immunotoxin might be a promising therapeutic approach for endosialin-positive neoplasia, especially synovial sarcoma, fibrosarcoma, malignant fibrous histiocytoma, liposarcoma, and osteosarcoma. Thus, a diagnostic/therapeutic targeted therapeutic approach to treatment of endosialin-expressing tumors may be possible.
Rouleau
Cecile
C
Genzyme Corporation, Framingham, Massachusetts 01701, USA. Cecile.Rouleau@Genzyme.com
Curiel
Maritza
M
Weber
William
W
Smale
Robert
R
Kurtzberg
Leslie
L
Mascarello
James
J
Berger
Carol
C
Wallar
Gina
G
Bagley
Rebecca
R
Honma
Nakayuki
N
Hasegawa
Kazumasa
K
Ishida
Isao
I
Kataoka
Shiro
S
Thurberg
Beth L
BL
Mehraein
Khodadad
K
Horten
Bruce
B
Miller
Glenn
G
Teicher
Beverly A
BA
D000818:Animals; D015703:Antigens, CD / Q000096:biosynthesis* / Q000235:genetics; D000951:Antigens, Neoplasm / Q000096:biosynthesis* / Q000235:genetics; D002277:Carcinoma / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D005434:Flow Cytometry; D006801:Humans; D007074:Immunoglobulin G / Q000494:pharmacology; D007150:Immunohistochemistry; D000922:Immunotoxins / Q000494:pharmacology*; D009369:Neoplasms / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D054789:Ribosome Inactivating Proteins, Type 1 / Q000633:toxicity; D000076985:Saporins; D012509:Sarcoma / Q000235:genetics / Q000378:metabolism*
D015703:Antigens, CD; D000951:Antigens, Neoplasm; C078203:CD248 protein, human; D007074:Immunoglobulin G; D000922:Immunotoxins; D012333:RNA, Messenger; D054789:Ribosome Inactivating Proteins, Type 1; D000076985:Saporins