PT  - JOURNAL ARTICLE
AU  - Landowski, Terry H.
AU  - Gard, Jaime
AU  - Pond, Erika
AU  - Pond, Gerald D.
AU  - Nagle, Raymond B.
AU  - Geffre, Christopher P.
AU  - Cress, Anne E.
TI  - Targeting Integrin α6 Stimulates Curative-Type Bone Metastasis Lesions in a Xenograft Model
AID  - 10.1158/1535-7163.MCT-13-0962
DP  - 2014 Jun 01
TA  - Molecular Cancer Therapeutics
PG  - 1558--1566
VI  - 13
IP  - 6
4099  - http://mct.aacrjournals.org/content/13/6/1558.short
4100  - http://mct.aacrjournals.org/content/13/6/1558.full
SO  - Mol Cancer Ther2014 Jun 01; 13
AB  - Laminin-binding integrin receptors are key mediators of epithelial cell migration and tumor metastasis. Recent studies have demonstrated a role for the α6 integrin (ITGA6/CD49f) in maintaining stem cell compartments within normal bone marrow and in residency of tumors metastatic to bone. In this study, we tested a function-blocking antibody specific for ITGA6, called J8H, to determine if preexisting cancer lesions in bone could be slowed and/or animal survival improved. Human prostate tumors were established by intracardiac injection into male SCID mice and treatment with J8H antibody was initiated after 1 week. Tumor progression was monitored by micro-computed tomography (CT) imaging of skeletal lesions. Animals that received weekly injections of the anti-ITGA6 antibody showed radiographic progression in only 40% of osseous tumors (femur or tibia), compared with control animals, where 80% of the lesions (femur or tibia) showed progression at 5 weeks. Kaplan–Meier survival analysis demonstrated a significant survival advantage for J8H-treated animals. Unexpectedly, CT image analysis revealed an increased proportion of bone lesions displaying a sclerotic rim of new bone formation, encapsulating the arrested lytic lesions in animals that received the anti-ITGA6 antibody treatment. Histopathology of the sclerotic lesions demonstrated well-circumscribed tumor within bone, surrounded by fibrosis. These data suggest that systemic targeting of the ITGA6-dependent function of established tumors in bone may offer a noncytotoxic approach to arrest the osteolytic progression of metastatic prostate cancer, thereby providing a new therapeutic strategy for advanced disease. Mol Cancer Ther; 13(6); 1558–66. ©2014 AACR.