Chloroform fraction of Scutellaria barbata D. Don inhibits the growth of colorectal cancer cells by activating miR-34a

Scutellaria barbata D. Don (SB) is a well known formula in traditional Chinese medicine, which exhibits potent anticancer effects on various cancers. Many miRNAs play crucial roles in the regulation of cancer, for instance, miR-34a functions as a tumor suppressor, and is often downregulated during cancer. In this study, we investigated the role of ECSB in suppressing the growth of human colon cancer HCT-8 cells, and whether this is mediated by regulation of miR-34a and its downstream target genes, using real-time PCR and western blot analysis. ECSB treatment significantly inhibited the proliferation of HCT-8 cells and promoted apoptosis in a dose dependent manner. In addition, ECSB treatment significantly increased the level of miR-34a expression and decreased the levels of Bcl-2, Notchl/2 and Jagged1 expression. Furthermore, knockdown of miR-34a expression through transfection of anti-miR-34a oligonucleotide was significantly reversed by ECSB treatment. Likewise, knockdown of miR-34a resulted in significant upregulation of Bcl-2, Notchl/2 and Jagged1 expression, which was reversed following ECSB treatment. Therefore, this study reveals that ECSB inhibited cancer cell growth via promoting apoptosis and inhibiting proliferation, through regulation of miR-34a. These findings further support the use of ECSB as an effective therapeutic agent against colon cancer.