[Down-regulation of metastatic phenotype in human melanoma cells by controlled expression of anti-sense matrix metalloproteinase 9].
OBJECTIVE
To investigate the correlation between matrix metalloproteinase 9 (MMP-9) expression and tumor invasion and metastasis as well, and to explore the potential application of controlled expression of target gene in tumor gene therapy.


METHODS
One self-contained tetracycline-regulated retroviral vector containing anti-sense cDNA of MMP-9 was constructed and transfected into a metastatic human melanoma cell line WM451 which expressed a high level of MMP-9. Techniques such as growth rate measurment, MTT assay, (3)H-thymidine incorporation, colony forming ability in soft agar, invasion assay in Boyden chamber, as well as zymography and Western blot were applied to analyze the expression of MMPs and behaviors of tumor cells in vitro before and after gene transfection. Tumorigenecity and spontaneous metastasis were tested in nude mice.


RESULTS
In the presence of exogenous tetracycline, the transfected antisense MMP-9 did not affect the endogenous level of MMP-9 in WM451 cells, and showed no significant changes in cell behaviors in comparison with that of the vector-transfected control cells. Nevertheless, withdrawal of tetracycline from the medium caused a significant down-regulation of expression and activity of MMP-9. The capacity of cell growth in vitro, colony forming ability in soft agar, invasion through Matrigel all were inhibited remarkably when compared with the controls. Spontaneous metastasis in nude mice was significantly inhibited.


CONCLUSIONS
Transfection of anti-sense MMP-9 can down-regulate the invasion and metastasis of melanoma cells both in vitro and in vivo, further clarifying the important role of MMP-9 in tumor progression.
Kong
Ling-ling
LL
Department of Pathology, Health Science Center, Peking University, Beijing 100083, China.
Fang
Wei-gang
WG
You
Jiang-feng
JF
Zhong
Hao-hao
HH
Zheng
Jie
J
D000818:Animals; D002455:Cell Division; D045744:Cell Line, Tumor; D016373:DNA, Antisense; D018076:DNA, Complementary / Q000235:genetics; D015536:Down-Regulation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D005822:Genetic Vectors; D006801:Humans; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis* / Q000235:genetics; D008545:Melanoma / Q000378:metabolism / Q000473:pathology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D009368:Neoplasm Transplantation; D012190:Retroviridae / Q000235:genetics; D013752:Tetracycline / Q000494:pharmacology*; D014162:Transfection
D016373:DNA, Antisense; D018076:DNA, Complementary; D020780:Matrix Metalloproteinase 9; D013752:Tetracycline