Purified sulforaphane from broccoli (Brassica oleracea var. italica) leads to alterations of CDX1 and CDX2 expression and changes in miR-9 and miR-326 levels in human gastric cancer cells

Background: Genetic alterations and epigenetic modifications are two main factors involved in gastric carcinogenesis, progression, and metastasis. Several miRNAs such as miRNA-9 and miRNA-326 may play important role in gastric cancer by targeting the 3'UTR of the caudal type homeobox (CDX) 1 and 2 mRNA respectively. The use of herbal medicines has been widely considered in the treatment of cancers such as gastric cancer. Sulforaphane extracted from broccoli may indirectly prevent cancer through affecting different signaling pathways. The aim of this study was to evaluate the effect of different concentrations of sulforaphane extracted from broccoli sprout (SEBS) on viability, death pattern, and expression alterations of CDX1/2 as well as miRNA-9 and miRNA-326 in normal (HF2FF) and gastric cancer cell lines. Methods: Two gastric cancer cell lines (AGS and MKN45) and HF2FF normal cell line were cultured and treated with different concentrations (31.25, 62.5, 125, and 250 mu g/ml) of the purified sulforaphane. Expression levels of CDX1 and CDX2 as well as miRNA-9 and miRNA-326, and mechanisms leading to cell death were assessed by Taqman real time PCR assay and flow cytometry, respectively. Results: Significant dose-dependent and anti-proliferative effects of the SEBS were observed on AGS and MKN45 cells after 48 h with an IC50 value of about 112 and 125 mu g/ml, respectively (P < 0.001). Apoptotic cells were observed in AGS and MKN45 cells but not HF2FF after 48 h of treatment with SEES. Furthermore, significant changes in expression of CDX1, CDX2, miR-9 and miR-326 in the gastric cancer lines (AGS and MKN45), were observed under different concentrations of SEBS. Conclusion: Our present study suggests that the SEBS may influence gastric cancer cell lines at specific doses and change their proliferation rate by altering the expression of CDX1, CDX2, miR-9, and miR-326.