Materials and Methods:
The cells were cultured in their recommended media supplemented with 10% FBS and antibiotics in 24-well tissue culture plates. At near confluence, the cells were treated with NM dissolved in media at 0, 10, 50, 100, 500 and 1000 μg/mL in triplicate. Parallel sets of cultures were also treated with phorbol 12-myristate 13-acetate (PMA) 100 ng/mL for induction of enzymes. After 24 h the media were collected and MMP-2 and MMP-9 levels were assayed by gelatinase zymography. Invasion studies were conducted using Matrigel in 24-well plates.
Results:
Correlation of pooled data from different cancer cell line groups demonstrated dose-dependent inhibition of MMP-2 and -9 and Matrigel invasion with NM treatment and significant negative correlation between MMP-2 and MMP-9 levels and Matrigel invasion. Pooled data of cell lines expressing only MMP-2 and resistance to PMA induction of MMP-9 showed significant negative correlation (r=-0.77, p=0.003) between MMP-2 secretion and inhibition of invasion through Matrigel. Cell lines expressing only MMP-9, showed significant negative correlation (r= -0.726, p=0.003) between MMP-9 secretion and Matrigel invasion. Pooled data of cell lines expressing MMP-2 and MMP-9 demonstrated significant negative correlation ( r = -0.821. p < 0.0001) between MMP-9 secretion and inhibition of invasion through Matrigel, Pooled data of cancer cell lines expressing no basal MMP-9 secretion demonstrated significant negative correlation ( r = -0.686, p < 0.0001) between PMA-induced MMP-9 secretion and inhibition of invasion through Matrigel.
Conclusions:
In conclusion, regardless of MMP-2 and MMP-9 patterns of expression, MMP modulation by NM was found to be significantly correlated with NM modulation of Matrigel invasion of these cell lines.
Key Words:
Human cancer cells, nutrient mixture, correlation of invasion with MMPs
Full Study: