Background: Breast cancer is the first noticeable disease in female patients. Long-term use of soybean (Glycine max) may prevent the progression of cancer. However, the molecular mechanism for the functions of soybean remains unclear. Histone demethylase JMJD5, an important epigenetic molecule, is overexpressed in the progression of breast cancer suggesting that soybean may ameliorate cancer by affecting the expression of JMJD5.
Materials and methods: To test the hypothesis, human breast cancer cell lines MCF-7 and MDA-MB-231 were treated with different concentrations of soybean and/or transfected with the plasmids pcDNA3.1-JMJD5 and pTZU6 + 1-shRNA-JMJD5. The growth rate was measured using xCELLigence real-time cell analysis. The level of JMJD5 was measured by using quantitative reverse transcription-polymerase chain reaction and Western blot.
Results: Soybean showed significant inhibitory effects on the growth rates ofMCF-7 and MDA-MB-231 cells in a concentration-dependent way (P < 0.05). Meanwhile, the levels of JMJD5 were reduced with the increase of soybean concentration (P < 0.05). JMJD5 transfection increased the growth rates of MCF-7 and MDA-MB-231 by 25% and 40%. In contrast, the growth rates of MCF-7 and MDA-MB-231 cells were decreased by 17% and 23% after being transfected with JMJD5 shRNA. Soybean inhibited the growth rate of MCF-7 and MDA-MB-231 cells when they were transfected by JMJD5 gene but no for the cells transfected with JMJD5 shRNA.
Conclusion: The complicated compositions of soybean will be beneficial to the therapy of breast cancer since its causes may be involved in multiple aspects. Soybean represses breast cancer development by downregulating the level of JMJD5.
Keywords: Breast cancer; histone demethylase JMJD5; soybean (Glycine max).