Maspin gene expression in tumor suppression induced by overexpressing manganese-containing superoxide dismutase cDNA in human breast cancer cells

Jian-Jian Li, N. H. Colburn, L. W. Oberley

Research output: Contribution to journalArticle

55 Scopus citations


We have reported the tumor suppressive effects of manganese-containing superoxide dismutase (MnSOD) in human breast cancer cells. In order to understand the molecular mechanism of this anti-tumor effect, we asked whether tumor suppressor gene(s), especially the ones inhibiting tumor invasion and motility, are involved in MnSOD-induced tumor suppression. Maspin is one of the serpin family of protease inhibitors that has been shown to function as a tumor-suppressor in human breast epithelium. In the present study, we demonstrated that maspin expression was up-regulated in human breast cancer MCF-7 cells that overexpress a normal MnSOD gene. The induced maspin transcripts were detected by RT-PCR and Northern blot and identified by sequencing. Maspin gene expression was induced in parallel with the level of exogenous MnSOD protein, which was induced by transfection with varied amounts of cDNA. In order to analyze cell invasion ability, which may be related to the induced maspin gene expression, MnSOD stable transfectants were tested using a matrigel invasion chamber. The invasion ability was reduced to 24% and 36% in the cloned (MCF + SOD) and pooled MnSOD-transfectants (MCF + SODp) respectively, compared with the wild-type MCF-7 cell line. In conclusion, these results suggest that overexpression of a normal MnSOD cDNA in human breast cancer cells up-regulates the gene expression of the protease inhibitor, maspin, which may play a role in the inhibitory function of MnSOD on tumor invasion.

Original languageEnglish (US)
Pages (from-to)833-839
Number of pages7
Issue number5
StatePublished - May 1998
Externally publishedYes


ASJC Scopus subject areas

  • Cancer Research

Cite this