M.W. Roomi, J.Monterrey, M. Rath and A. Niedzwiecki
Dr. Rath Research Institute, 1260 Memorex Drive, Santa Clara, CA 95050

Presented at: 
53rd Annual Meeting of the Society of Toxicology, March 23-27, 2014, Phoenix, AZ
Published in: 
The Toxicologist, vol 138(1), Abstract #1088, pg 288

Abstract

Introduction: Strong clinical and experimental evidence demonstrates association of elevated levels of matrix metalloproteinase (MMP)-9 with cancer progression, metastasis and shortened patient survival, as it plays a key role in tumor cell invasion and metastasis by digesting the basement membrane and ECM components. MMP-9 is secreted in both monomer and dimer forms. Though there is little research on MMP-9 dimers, some studies have shown the dimer to be associated with more aggressive tumor progression. 
Objective:9 dimer in various carcinomas, sarcomas, adenocarcinomas and leukemias and the effect of a nutrient mixture (NM) containing lysine, proline, ascorbic acid and green tea extract on dimer secretion.  
Materials and Methods: The cancer cell lines were grown in their respective media, supplemented with 10% FBS, penicillin (100 units/ml), and streptomycin (100 g/ml) in 24-well tissue culture plates. At near confluence, the cells were treated with NM at 0,10, 50, 100, 500 and 1000 µg/ml. Parallel sets of cultures were treated with phorbol 12-myristate 13-acetate (PMA) 100 ng/ml for induction of MMP-9. Cell MMP-9 secretion was assayed by gelatinase zymography.
Results: No MMP-9 dimer secretion was observed in prostate, pancreatic, colon, bladder, head and neck, glioblastoma and leukemia cell lines. MMP-9 dimer secretion only with PMA induction was seen in sarcomas, melanoma and breast, lung and tongue cancer cell lines. Cervical, renal and hepatic carcinomas exhibited MMP-9 dimer without PMA treatment and increased secretion with PMA treatment. Sarcomas demonstrated the highest combined levels of MMP-9 monomer and dimer with and without PMA among these cancer cell lines. NM showed dose-dependent inhibition of MMP-9 monomer and dimer in all cell lines tested. 
Conclusion: In conclusion, high MMP-9 secretion levels correlated with more aggressive cancer cell lines. NM was effective in inhibiting MMP-9 monomer and dimer secretion in all cell lines tested, suggesting its therapeutic potential as an antimetastatic agent.

Comments

Strong clinical and experimental evidence demonstrates association of elevated levels of matrix metalloproteinase MMP-9 with cancer progression, metastasis and shortened patient survival, as it plays a key role in tumor cell invasion and metastasis by digesting the basement membrane and ECM components. MMP-9 is secreted in both the monomeric and dimeric form. In addition to proteolysis, MMP-9 has been shown to play an important role in cell migration. It has been demonstrated that the MMP-9 dimer (present usually as 10-15% of the MMP-9 population), not the monomer, is required for cell migration functional activity of MMP-9.In our study, sarcomas had the highest levels of MMP-9 monomer and dimer combined with and without PMA among these cancer cell lines. In addition, osteosarcoma showed the highest MMP-9 dimer to MMP-9 ratio, indicating a very aggressive cancer. Cervical, uterine, and male breast cancer cell lines showed the next highest levels of combined MMP-9, followed by breast cancer cell lines. Melanoma, renal, lung, head and neck and hepatocellular carcinoma showed lower levels and prostate, glioblastoma, bladder and leukemia cell lines the lowest. The NM showed dose-dependent inhibition of MMP-9 monomer and dimer in all cell lines tested. The results of this study are significant as they demonstrated that high MMP-9 and dimer secretion levels correlated with the most aggressive cancer cell lines. The nutrient mixture was effective in inhibiting MMP-9 and dimer secretion in all cell lines tested, suggesting its therapeutic potential as an antimetastatic agent, but one that would not pose any toxic effect clinically, as documented in our previous in vivo studies.