Gene expression profiling and pathway network analysis of anti-tumor activity by Jaridon 6 in esophageal cancer
Jaridon 6, a novel ent-kaurene diterpenoid derived from Rabdosia rubescens (Hemsl.) Hara, possesses strong anti-tumor activity in esophageal cancer cells. In this study, we explored the underlying molecular events of the anti-tumor activity of Jaridon 6. Cell viability and apoptosis results obtained by flow cytometry confirmed the tumor inhibitory effect of Jaridon 6 in esophageal cancer cells. A cDNA microarray was performed and the observations were validated using quantitative reverse transcription polymerase chain reaction. The microarray data showed that 151 genes were differentially expressed between the untreated group and the Jaridon 6-treated group, among these were 57 upregulated genes, and 94 downregulated genes (P < 0.01, fold change threshold: 2). These included genes such as Wnt, peroxisome, and genes involved in chemokine signaling pathways. In addition, Western blot analysis demonstrated that Jaridon 6 regulated the expression of Wnt pathway proteins, including reduced levels of Dvl 2, survivin and cyclin D1, and increased levels of p-β-catenin, and AXIN2 in EC109 and EC9706 esophageal cancer cells. In addition, recombinant murine Wnt3a could change the regulation of Jaridon 6 on Wnt pathway proteins. Immunohistochemical analysis indicated that the anti-tumor activity of Jaridon 6 was closely related to the Wnt signaling pathway in esophageal cancer cells.