## 4 Discussion
### Selectivity Index of S. triloba for U2 OS and SKOV3 Cells
triloba Acetone Extract and Its Combination with Paclitaxel Increase the Percentage of Non-Viable Cells in SKOV3 Cells_  
We employed the trypan blue assay to determine the percentage of non-viable (dead) U2 OS and SKOV3 cells after treatment with either _S. triloba_ acetone extract alone, or when in combination with paclitaxel. Although the percentage of non-viable U2 OS cells increased by almost 18% after _S. triloba_ treatment, the results displayed no statistical significance. Contrarily, the percentage of non-viable SKOV3 cells was significantly greater (44%) after _S. triloba_ treatment. The greatest increase in non-viable cells (92%) was, however, observed when _S. triloba_ acetone extract and paclitaxel were applied to SKOV3 cells in combination. Since trypan blue dye stains cells with disrupted membranes [41], it is probable that after _S. triloba_ treatment, the observed reduction in SKOV3 cell viability in the MTT assay involves the induction of necrotic cell death pathways that induce a rapid loss in membrane integrity [72; 73]. The activation of these pathways can be further amplified by the combination treatment. On the other hand, the decreased viability of U2 OS cells in the MTT assay probably occur via other cell death pathways that do not lead to rapid losses in cell membrane integrity [72; 73]. Besides this, _S. triloba_ was reported to induce both apoptotic and necrotic cell death in T47D breast cancer cells through p21 [24]. _S. triloba and Its Combination with Paclitaxel Respectively Display Anti-Migratory Properties in U2 OS and SKOV3 Cells_  
Metastasis is the leading cause of cancer-related fatalities, and is a complex process involving cell- migration and invasion [74]. As such, we assessed the anti-migratory potential of _S. triloba_ in both U2 OS and SKOV3 cells using both the scratch-wound healing assay and the transwell migration assay. The wound healing assay displayed diminished migration of U2 OS and SKOV3 cells after _S. triloba_ treatment. On the other hand, after treatment with _S. triloba_, only U2 OS cells displayed substantial declines in cell migration when the transwell assay was conducted. A significant decrease in SKOV3 cells was only observed for the combination treatment. Several plant derived phenolic compounds were shown to inhibit cancer cell migration by modulating a range of cellular process involved in epithelial-to-mesenchymal transition (EMT), cell invasion, and extravasation [75]. Carnacic acid, an abundant diterpene in _S. triloba_ exhibited anti-migratory effects by down-regulating COX-2 in colorectal cancer [76; 77; 78]. Carnacic acid further blocked the migration of B16F10 melanoma cells through the inhibition of EMT [77; 78]. Our results additionally suggest that the synergistic interaction between _S. triloba_ and paclitaxel considerably improves the anti-migratory effect of either treatments. [PERSON] and colleagues reported a marked increase in SKOV3 cell migration and invasion, along with a down regulation of E-cadherin and MTA3 after combined treatment with \(\beta\)-elemene and paclitaxel [79]. _S. triloba_ and Its Combination with Paclitaxel Modulate the Steady-State mRNA Expression of Genes Involved in Cell Proliferation and Migration  
The effect of _S. triloba_ acetone extract on the steady-state mRNA expression of several markers implicated in both osteosarcoma and ovarian adenocarcinoma progression was further examined. Since the RUNX2, (PI3K)/ AKT, p53, and \(\beta\)-catenin pathways are often abrogated in both osteosarcoma and ovarian adenocarcinoma, we evaluated how _S. triloba_ affects the steady-state expression of key genes associated with these pathways. The RUNX2 transcription factor is a regulator of both osteogenesis and osteogenic differentiation. Normally, RUNX2 acts as a suppressor or promotor of cell proliferation depending on either cell cycle stage or cell type. In osteosarcoma, RUNX2 expression is regularly elevated; moreover, evidence of increased RUNX2 DNA copy number, mRNA, and protein have been reported [80].