Matrix metalloproteinases 2 and 9 in oral squamous cell carcinomas: manifestation and localization of their activity.
OBJECTIVE
The process of invasion and metastasis is closely related to the prognosis of oral squamous cell carcinoma (OSCC). Matrix metalloproteinases (MMPs) are a group of enzymes characterized by their ability to degrade extracellular matrix proteins and contribute to the tumor invasion and metastasis. Especially MMP-2 and MMP-9 are known to be related to destruction of basement membrane as collagenases. This study focused on protein expression of MMP-2 and MMP-9 and their extracellular matrix degradation activity in OSCCs.


METHODS
Freshly frozen samples from 31 OSCC patients were analyzed for the localization and activity of MMP-2 and MMP-9. Serial frozen sections were used by routine hematoxylin and eosin staining, immunohistochemistry for MMP-2 and MMP-9, and film in situ zymography (FIZ) for gelatinolytic activity. We also evaluated the activity of MMP-2 and MMP-9 by zymography using the same samples as frozen sections. The activated form/proform ratio of MMPs in zymography was evaluated using an image scanner.


RESULTS
In MMP-2 the proportion in T3 and T4 clinical stage groups was significantly higher than that in T1 and T2. The proportion in lymph node metastasis cases (N+) was also significantly higher than that in non-lymph node metastasis cases (N-). In contrast to MMP-2, the activated form/proform ratio of MMP-9 was very low, suggesting that MMP-9 is not activated in the matrix degradation of OSCC, although both MMP-2 and MMP-9 protein expression are presented in tumor cells. FIZ revealed MMP in both tumor cells and stromal cells of 70% of the N+ cases and of 47.6% of the N- cases.


CONCLUSIONS
These results indicate that two types of proform and activated form matrix metalloproteinases, MMP-2 and MMP-9, are present in human OSCC, and that the activated MMP-2 could be a main enzymatic activity of gelatinolysis in OSCC. Interaction of tumor cells and stromal cells seems to play an important role in the invasion and metastasis of human OSCC. Combination analysis of zymography and FIZ is a useful method to detect activity and localization of MMPs in human OSCC.
Kato
Keizo
K
Department of Oral and Maxillofacial Sciences, Graduate School of Medicine, Gifu University, 1-1 Yanagido, 501-1194, Gifu, Japan. keizo@cc.gifu-u.ac.jp
Hara
Akira
A
Kuno
Toshiya
T
Kitaori
Nami
N
Huilan
Zhi
Z
Mori
Hideki
H
Toida
Makoto
M
Shibata
Toshiyuki
T
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000201:enzymology* / Q000556:secondary; D005260:Female; D005780:Gelatin; D006801:Humans; D007124:Immunoenzyme Techniques; D008207:Lymphatic Metastasis / Q000473:pathology; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000201:enzymology* / Q000473:pathology; D009361:Neoplasm Invasiveness / Q000473:pathology; D009367:Neoplasm Staging; D017154:Stromal Cells / Q000201:enzymology / Q000473:pathology
C015233:gelatin film; D005780:Gelatin; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9