Human CC chemokine Macrophage Inflammatory Protein-3α (MIP-3α) directs inflammatory cell migration through its binding to the transmembrane receptor CCR6. MIP-3α has recently been shown to promote tumor cell migration in pancreatic adenocarcinoma by up-regulation of matrix metalloproteinases (MMPs). We hypothesized that MIP-3α promotes pancreatic cancer invasion through the up-regulation of MMP-9, a Type 4 collagenase. Immunohistochemistry and RT-PCR confirmed the presence of MIP-3α in PANC-1 cells, a human pancreatic adenocarcinoma cell line. MIP-3α stimulated the production of both latent and active forms of MMP-9 in PANC-1 by Western analysis. Tumor cell invasion was then evaluated using a modified Boyden chamber invasion assay. MIP-3α promoted a dose-dependent increase in pancreatic cancer cell invasion (P < 0.05) at 100 ng/ml. The activity at the putative MIP-3α receptor, CCR6, was demonstrated by receptor blockade. Anti-CCR6 antibody and anti-MMP-9 antibody inhibited MIP-3α-stimulated PANC-1 cell invasion of collagen to 37% and 35% of control, respectively (P < 0.05). MIP-3α, through its CCR6 receptor, promotes tumor cell invasion by the up-regulation of MMP-9. Molecular based therapy aimed at the inhibition of MIP-3α activity through the CCR6 receptor may serve as a future target to prevent tumor cell invasion in pancreatic adenocarcinoma. © 2004 Elsevier Inc. All rights reserved.