We investigated the effect of NM on the tumor growth of human lung carcinoma cell A-549 xenografts in athymic nude mice. Additionally, we tested the in vitro antitumor effect of NM on lung carcinoma A-549 cells by measuring: cell proliferation by MTT assay, MMP-2 and –9 secretion by gelatinase zymography and cell invasion through Matrigel.
Nutrient supplementation strongly suppressed the growth of tumors without adverse effects in nude mice; tumor weight was reduced by 44% (p=0.0001) and tumor burden was reduced by 47% (p<0.0001) with supplementation. Zymography demonstrated in vitro secretion of MMP-2 by uninduced human lung carcinoma cells and both MMP-2 and-9 by PMA (200 ng/ml)- treated cells. NM inhibited the secretion of both MMPs in a dose-dependent fashion with virtual total inhibition at 500 µg/ml concentration. The invasion of human lung carcinoma cells through Matrigel was significantly reduced at 100 µg/ml (64%) and totally inhibited at 500-µg/ml concentration of NM (p=0.01).
Suppression of lung tumor growth in nude mice and inhibition of MMP secretion and Matrigel invasion suggest NM as a potential non-toxic therapeutic agent for lung cancer.