Development of an orthotopic canine prostate cancer model expressing human GRPr.

Tweedle MF, Ding H, Drost WT, Dowell J, Spain J, Joseph M, Elshafae SM, Menendez MI, Gong L, Kothandaraman S, Dirksen WP, Wright CL, Bahnson R, Knopp MV, Rosol TJ
Prostate in press 07/11/2018


BACKGROUND: Ace-1 canine prostate cancer cells grow orthotopically in cyclosporine immunosuppressed laboratory beagles. We previously transfected (human Gastrin-Releasing Peptide Receptor, huGRPr) into Ace-1 cells and demonstrated receptor-targeted NIRF imaging with IR800-G-Abz4-t-BBN, an agonist to huGRPr. Herein, we used the new cell line to develop the first canine prostate cancer model expressing a human growth factor receptor.

METHODS: Dogs were immunosuppressed with cyclosporine, azathioprine, prednisolone, and methylprednisolone. Their prostate glands were implanted with Ace-1

RESULTS: Dog1 grew no tumors with cyclosporine alone. Using the four drug protocol, Dogs 2-6 grew abundant 1-2 mm intracapsular and 1-2 cm intraglandular tumors. Tumors grew >5 cm when the prostate cancer cells became extracapsular. Dogs 4-6 with sealed prostatic capsule implantation sites had growth of intracapsular and intraglandular tumors and LN metastases at 5 weeks. High tumor to background BPH signal in the NIRF images of sectioned prostate glands resulted from the 100 nmol dose (∼8 nmol/kg) in dogs 2-4 and 50 nmol dose in dog 5, but not from the 25 nmol dose in Dog 6. Imaging of mouse Ace-1


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