In vitro and in vivo matrix metalloproteinase production by pancreatic cancer cells and by distant organs.
BACKGROUND
Matrix metalloproteinases (MMP), especially MMP-2 and MMP-9, are thought to play major roles in pancreatic cancer growth and metastasis. MMP inhibition prolongs survival in a murine model of human pancreatic cancer. To establish an in vitro model of human pancreatic cancer, we sought to determine in vitro MMP production by two human pancreatic cancer cell lines, compare in vitro to in vivo production, and, if different, determine if in vitro MMP production could be made to mimic in vivo production by altering the in vitro environment of the cell lines. We also sought to document that in vivo production of MMP was unique to orthotopic pancreatic cancer cells.


METHODS
HPAC and PANC-1 cell lines were grown in vitro and in a murine model of orthotopic pancreatic cancer. MMP-2 and MMP-9 production by the cell lines was determined. Noting differences between in vitro and in vivo production, the cell lines were stimulated in vitro with PMA. Orthotopic pancreatic tumor MMP production was compared to splenic, hepatic, and renal production of MMP. MMP-2 and MMP-9 production was sought in both active and latent forms utilizing gelatin zymography. Results were confirmed by Western blot. Densitometry allowed comparisons: scale 0 (none) to ++++ (most).


RESULTS
In vitro, HPAC and PANC-1 produce modest amounts of MMP-2 and MMP-9, mostly in latent form. In vivo, both cell lines produce more MMP, particularly in the active forms. In vitro stimulation of the cell lines with the PMA increased MMP production, particularly of active MMP-2 and latent MMP-9, resulting in a profile of MMP production similar to that seen in vivo. Hepatic, renal and splenic MMP levels, especially active forms, were very low relative to the tumors.


CONCLUSIONS
Pancreatic cancer cell lines produce less MMP, especially active form, in vitro than in vivo. With in vitro stimulation, the MMP profile of cell lines mimic those of tumors in vivo, suggesting that cancer cells are stimulated in vivo. Both in vitro and in vivo, the poorly differentiated cell line PANC-1 is associated with broadened and enhanced MMP activity. Healthy solid organs produce little MMP-2 or MMP-9, most of which is latent form.
Haq
M
M
Department of Surgery, University of South Florida, Tampa 33601, USA.
Shaeii
A E
AE
Zervos
E E
EE
Rosemurgy
A S
AS
D000818:Animals; D006801:Humans; D020778:Matrix Metalloproteinase 2 / Q000096:biosynthesis*; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis*; D051379:Mice; D008807:Mice, Inbred BALB C; D010190:Pancreatic Neoplasms / Q000201:enzymology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9; D013755:Tetradecanoylphorbol Acetate