Addition of Matrix Metalloproteinase Inhibition to Conventional Cytotoxic Therapy Reduces Tumor Implantation and Prolongs Survival in a Murine Model of Human Pancreatic Cancer

Matrix metalloproteinases (MMPs) participate in basement membrane degradation, a critical step in invasion of cancer cells. We have previously shown that MMP inhibition of pancreatic cancers improves survival and decreases MMP production in vivo. The purpose of this study was to determine whether BB-94 was better than cytotoxic therapy and would increase the efficacy of cytotoxic therapy (gemcitabine) in a murine model of human pancreatic cancer. A human pancreatic adenocarcinoma cell line (HPAC) was injected into the pancreata of BALB/c nu/nu mice. The mice were randomized 7 days after cancer cell injection to receive vehicle control, BB-94, gemcitabine, or gemcitabine and BB-94 until death or sacrifice at 84 days. At necropsy, tumors were harvested, and the relative enzyme activities of MMP-2 and MMP-9 were determined by gelatin zymography. Active MMP-2 levels in serum were determined using an ELISA technique. Combination treatment with gemcitabine and BB-94 significantly reduced implantation rates and improved survival in mice with documented orthotopic tumors compared with either therapy alone or control. Tumor levels of active and latent MMP-2 were higher than those of MMP-9 in both treated and control mice. There was a significant reduction of tumor MMP-2 activity in mice treated with BB-94, gemcitabine, or gemcitabine and BB-94. Serum levels of active MMP-2 were reduced in all treated groups, with the greatest reduction occurring in mice treated with gemcitabine and BB-94. Combination therapy with gemcitabine and BB-94 reduces cancer implantation and improves survival compared to treatment with BB-94, gemcitabine, or vehicle control alone. MMP production was reduced in all treated groups, reflecting reduced tumor progression, which was particularly seen with combination therapy with gemcitabine and BB-94. This study supports combining MMP inhibition with cytotoxic therapy (gemcitabine) for patients with pancreatic cancer.