Abstract 1926: Selective induction of apoptosis by aqueous extract of Chinese medicinal herbs Scutellaria barbata and Oldenlandia diffusain HCT 116 colon cancer cells and CCD 841 CoN colon epithelial cells

Scutellaria barbata (SB) and Oldenlandia diffusa (OD) have been used in traditional Chinese medicine for treating liver, lung and rectal tumors. These two herbs are included in most of the herbal cancer treatment formulas in Taiwan hospitals. We previously showed that aqueous extracts of SB and OD inhibited mutagenesis, DNA binding and metabolism of aflatoxin B1 and benzo(a)pyrene. They were also shown to inhibit foci formation in the colon of AOM-induced mice. Other researchers demonstrated their effects in regulation of various apoptotic enzymes and pathways. Ethanol extract of SB was shown to inhibit colorectal cancer growth by suppression of the Wnt/β-catenin signaling pathway while ethanol extract of OD was indicated in the inhibition of proliferation and induction of apoptosis of 5-FU resistant colorectal cancer cells via the regulation of PI3K/AKT signaling pathway. In this study, the effects of aqueous extracts of SB and OD on the induction and modulation of apoptosis in HCT 116 colon cancer cells and CCD 841 CoN normal color epithelial cells were assessed using TUNEL assay, Apoptosis/Necrosis Detection Kit, and Human Apoptosis Antibody Array - Membrane (43 Targets) test (Abcam). Our data demonstrated that both the 3-hours and 6 hours of 1.5 mg/mL SB treatments induced apoptosis in HCT 116 colon cancer cells significantly (77.5 ± 1.5%, 87.5± 3.5%) as compared to the negative control (13.5 ± 0.5%, 17.0 ± 6.0%), p < 0.05. The percent of apoptosis was not significantly different as compared to that of the positive control induced by 1µMol Staurosporine (99.5 ± 0.5%, 91.9 ± 9.0%); while there was no notable induction of apoptosis in normal CCD 841 CoN colon epithelial cells (18.5 ± 1.5%, 14.4 ± 4.0% separately). The majority of the normal cells remained non-induced (71.0 ± 1.0%, 68.5 ± 6.5%). A similar selective induction of apoptosis, in the two cell lines separately, was obtained from the 3-hours and 6 hours of 1.5 mg/mL OD treatments (HCT116 - 44.0 ± 4.0%, 83.5± 15.5%; CCD841 CoN - 6.5 ± 5.5%, 7.0 ± 2.0% respectively). Modulation of various apoptosis markers production such as up-regulation of Bax, BID, Bad, p27, p53, Caspases 8 and 3; and down-regulation of Bcl-2 and Bcl-w was also observed. These results suggested that SB and OD contain phytochemicals which selectively induce apoptosis in HCT 116 cancer cells by modulating these markers while not significantly affecting the normal CCD 841 CoN colon epithelial cells. Further study of their specific