Huanglian (Coptidis rhizoma), a widely used herb in
traditional Chinese medicine, has been shown recently to possess anticancer activities. However, the molecular mechanism underlying the anticancer effect of the herb is poorly understood. Specifically, whether
huanglian extract affects the expression of
cancer-related genes has not been defined. This study used
DNA microarray technology to examine the effect of the herbal extract on expression of the common genes involved in
carcinogenesis in two human
breast cancer cell lines, the ER-positive MCF-7 and ER-negative MDA-MB-231 cells. Treatment of the
cancer cells with
huanglian extract markedly inhibited their proliferation in a dose- and time-dependent manner. The growth inhibitory effect was much more profound in MCF-7 cell line than that in MDA-MB-231 cells.
DNA microarray assay revealed that treatment with
huanglian dramatically increased the
mRNA expression of
interferon-beta (IFN-beta) and
tumor necrosis factor-alpha in MCF-7 cells. Quantitative analysis by real-time PCR or western blotting confirmed the upregulation of the two genes (especially IFN-beta) in MCF-7 cells, but not in MDA-MB-231 cells. Addition of
neutralizing antibody against IFN-beta to culture medium markedly inhibited the
huanglian-induced antiproliferative effect, confirming the involvement of IFN-beta in the
huanglian's effect and also suggesting an autocrine pathway for the action of IFN-beta in this setting. Given that IFN-beta is among the most important anticancer
cytokines, the upregulation of this gene by
huanglian is, at least in part, responsible for its antiproliferative effect. The results of this study implicate
huanglian as a promising herb for
chemoprevention and
chemotherapy of certain
cancers.