Group A was fed a regular diet and group B a regular diet supplemented with 0.5% NM. Four weeks later, the mice were sacrificed and their tumors were excised, weighed and processed for histology. We also tested the effect of NM in vitro. NM inhibited the growth of xenograft tumors by 22% (p=0.04) and, in vitro, dose-dependent inhibition of cell proliferation with a decrease of 27% (p=0.001) and 36% (p=0.002) at 500 and 1000 μg/ml NM compared to control, respectively. Zymography showed MMP-2 secretion in normal cells and PMA (100 ng/ml)-induced MMP-9 secretion. NM inhibited the secretion of both MMPs with total blockage at 100 μg/ml concentration. Reverse zymography demonstrated dose-dependent increase in TIMP-2 expression by NM. Interestingly, human neuroblastoma SK-N-MC cells were not invasive through Matrigel. NM induced dose-dependent apoptosis of SK-N-MC cells. The results suggest NM may have therapeutic potential in treating neuroblastoma.

Key words: 
neuroblastoma SK-N-MC, tumor growth, MMP-2 and-9, apoptosis

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http://www.spandidos-publications.com/10.3892/or.2013.2307