Hypoxia augments gelatinase activity in a variety of adenocarcinomas in vitro.
BACKGROUND
Hypoxia within solid adenocarcinomas and protease up-regulation has been independently implicated as poor prognostic indicators in a variety of tumor types. The authors hypothesize that Matrix Metalloproteases (MMP) are up-regulated in direct response to a hypoxic environment.


METHODS
Colonic (SW1222), breast (MDA-MB231), and pancreatic (PSN-1) tumor cell lines were exposed to hypoxia (1% oxygen/94% nitrogen/5% carbon dioxide) for periods of up to 24 h. Reaction to a hypoxic environment was determined via invasion across a Matrigel-coated 8-microm Transwell filter. Activity of MMP 2 and 9 was assessed using gelatin zymography. Expression of tissue inhibitor of metalloproteases 1 (TIMP-1) was quantified using ELISA (Biotrak). Correlation between protease expression and invasive capacity was determined using a specific gelatinase inhibitor (MMPI; Calbiochem).


RESULTS
All tumor lines demonstrated augmented invasion over 72 h (P < 0.01 all groups). Concomitant significant increase in MMP 2 and 9 activity was observed in the SW1222 and PSN-1 lines. MDA-MB231s showed increase in MMP 9 expression and in a unidentified 103-kDa gelatinase (P < 0.001). The hypoxia-augmented invasion was attenuated by the addition of a specific gelatinase inhibitor confirming interdependence.


CONCLUSIONS
Hypoxia induces an increased invasive capacity via gelatinase up-regulation without loss of cell viability. This suggests a mechanism explaining the poorer prognosis seen in patients with protease-secreting solid adenocarcinomas.
Ridgway
Paul F
PF
Department of Surgical Oncology and Technology, Imperial College, St. Mary's Hospital, London, United Kingdom. p.ridgway@ic.ac.uk
Ziprin
Paul
P
Alkhamesi
Nawar
N
Paraskeva
Paraskevas A
PA
Peck
David H
DH
Darzi
Ara W
AW
D000230:Adenocarcinoma / Q000378:metabolism* / Q000473:pathology; D001943:Breast Neoplasms; D045744:Cell Line, Tumor; D002470:Cell Survival; D003110:Colonic Neoplasms; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D000860:Hypoxia / Q000378:metabolism* / Q000473:pathology; D066298:In Vitro Techniques; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D061965:Matrix Metalloproteinase Inhibitors; D009361:Neoplasm Invasiveness; D010190:Pancreatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism; D015854:Up-Regulation
D004791:Enzyme Inhibitors; D061965:Matrix Metalloproteinase Inhibitors; D019715:Tissue Inhibitor of Metalloproteinase-1; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9