Targeting COX-2 and EP4 to control tumor growth, angiogenesis, lymphangiogenesis and metastasis to the lungs and lymph nodes in a breast cancer model.
We reported that cyclo-oxygenase (COX)-2 expression in human breast cancer stimulated cancer cell migration and invasiveness, production of vascular endothelial growth factor (VEGF)-C and lymphangiogenesis in situ, largely from endogenous PGE2-mediated stimulation of prostaglandin E (EP)1 and EP4 receptors, presenting them as candidate therapeutic targets against lymphatic metastasis. As human breast cancer xenografts in immuno-compromised mice have limitations for preclinical testing, we developed a syngeneic murine breast cancer model of spontaneous lymphatic metastasis mimicking human and applied it for mechanistic and therapeutic studies. We tested the roles of COX-2 and EP receptors in VEGF-C and -D production by a highly metastatic COX-2 expressing murine breast cancer cell line C3L5. These cells expressed all EP receptors and produced VEGF-C and -D, both inhibited with COX-2 inhibitors or EP4 (but not EP1, EP2 or EP3) antagonists. C3H/HeJ mice, when implanted SC in both inguinal regions with C3L5 cells suspended in growth factor-reduced Matrigel, exhibited rapid tumor growth, tumor-associated angiogenesis and lymphangiogenesis (respectively measured with CD31 and LYVE-1 immunostaining), metastasis to the inguinal and axillary lymph nodes and the lungs. Chronic oral administration of COX-1/COX-2 inhibitor indomethacin, COX-2 inhibitor celecoxib and an EP4 antagonist ONO-AE3-208, but not an EP1 antagonist ONO-8713 at nontoxic doses markedly reduced tumor growth, lymphangiogenesis, angiogenesis, and metastasis to lymph nodes and lungs. Residual tumors in responding mice revealed reduced VEGF-C and -D proteins, AkT phosphorylation and increased apoptotic/proliferative cell ratios consistent with blockade of EP4 signaling. We suggest that EP4 antagonists deserve clinical testing for chemo-intervention of lymphatic metastasis in human breast cancer.
Departments of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada.
Xiping
X
Xin
Mousumi
M
Majumder
Gannareddy V
GV
Girish
Vik
V
Mohindra
Takayuki
T
Maruyama
Peeyush K
PK
Lala
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D052246:Cyclooxygenase 2 Inhibitors / Q000494:pharmacology*; D005260:Female; D008175:Lung Neoplasms / Q000556:secondary*; D042583:Lymphangiogenesis / Q000187:drug effects; D008325:Mammary Neoplasms, Experimental / Q000098:blood supply / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology*; D051379:Mice; D008809:Mice, Inbred C3H; D058990:Molecular Targeted Therapy; D009362:Neoplasm Metastasis; D009389:Neovascularization, Pathologic / Q000188:drug therapy; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D058309:Receptors, Prostaglandin E, EP4 Subtype / Q000037:antagonists & inhibitors*; D042582:Vascular Endothelial Growth Factor C / Q000378:metabolism; D042643:Vascular Endothelial Growth Factor D / Q000378:metabolism
D052246:Cyclooxygenase 2 Inhibitors; C545651:Ptger4 protein, mouse; D058309:Receptors, Prostaglandin E, EP4 Subtype; D042582:Vascular Endothelial Growth Factor C; D042643:Vascular Endothelial Growth Factor D; C467483:vascular endothelial growth factor C, mouse; C077623:Ptgs2 protein, mouse; D051546:Cyclooxygenase 2; D051057:Proto-Oncogene Proteins c-akt