The Traditional Chinese Medicine (TCM) formulation Shexiang Baoxin Pill (SBP) is commonly used in the treatment of coronary heart disease (CHD) in East Asia and regarded to promote the regulation of angiogenesis and to improve endothelial function. SBP comprises of seven TCM materials; however, the interactions of their effects in a biological system are unknown. In this work we developed an algorithm to predict the synergy of pairwise combinations of 22 compounds present in SBP. The algorithm is based on the targets of the compounds network properties in an angiogenesis- and CHD-specific network. We evaluated our synergy score prospectively by testing the 20 highest-ranked and the 20 lowest-ranked compound combinations for their synergistic potential to promote cell proliferation of human umbilical vascular endothelial cells. Results showed that 70 % of the 20 highest-ranked combinations increased cell proliferation synergistically, while only 30 % of the 20 lowest-ranked combinations had a synergistic effect. Based on the target and pathway predictions for the combinations, we hypothesized that two complementary pathways are responsible for the synergistic effect, apoptosis through caspase-3 and caspase-8 and cell growth through the proto-oncogene c-Fos and fibroblast growth factor 1. Hence, in this work we introduce an algorithm which was able to increase the probability of identifying compound pairs from SBP exhibiting synergy, which was experimentally validated in a disease-relevant model. Furthermore, we were able, based on this model, to provide a hypothesis for interactions causing synergy to promote endothelial cell growth.
Pristimerin is a quinonemethide triterpenoid compound that exerts anticancer activities against different cancer cells, including colorectal cancer. The current study aimed to study the cytotoxic and apoptosis-inducing effects of pristimerin alone or in combination with docetaxel on HCT-116 human colorectal cancer cell line. The cytotoxicity of pristimerin, or docetaxel, or the combination on HCT-116 cells were measured using the MTT method. The combination index (CI) was calculated using the isobologram method of Chou and Talalay. Annexin V/PI double staining was used to assess the apoptosis-inducing effect of these agents. Our results showed that both pristimerin and docetaxel showed potent cytotoxic effects against HCT-116 cells in dose-dependent manners. Moreover, the efficacy of docetaxel combined pristimerin was significantly increased, compared to individual treatment. The CI value was (0.55 to 0.89) that indicated the synergistic interaction between two agents to inhibit cell growth of CRC cells. Furthermore, Annexin V/PI assay showed that both agents induced apoptosis in HCT-116 in cancer cells. While treatment with combination resulted in a significant enhancement in apoptosis rates compared to individual treatment. Collectively, the data indicated that pristimerin potentiated the anticancer activities of docetaxel in colon cancer cells by reducing cell viability and promoting apoptosis.