Resistance to therapies, recurrence, and metastasis remain challenging issues for breast cancer patients, particularly for triple-negative and breast cancer stem cells. The activation of the epithelial-to-mesenchymal transition (EMT) plays an indispensable role in the poor prognosis of those types. The accumulating proofs indicated that the mevalonate pathway crucially mediates a poor prognosis. Here, the effects of lipophilic 3-hydroxy-3-methyl-glutaryl-coenzyme A inhibitors, atorvastatin, lovastatin, and simvastatin, were investigated on expression and function of a selected profile of EMT-related genes in breast cancer stem-like cells. A nontoxic dose of statins (5 μM for 4 days) significantly (P < 0.05 and >2-fold change) altered expression of 50 of 71 studied genes with a shared cluster of 37 genes that are coding chief operator of signaling pathways in Hippo, Notch, Wnt, proliferation, invasion, angiogenesis, and cell death. They also significantly decreased the levels of Yap/Taz proteins and shifted the expression of vimentin/E-cadherin in favor of induction of differentiation. Statins significantly chemosensitized the treated cells to doxorubicin and also reduced in vitro migration of the cells. Whereas lovastatin and simvastatin significantly decreased the expression of CD44, atorvastatin drastically increased CD24 and caused more wide-ranging impacts. In summary, the statins hold back the process of EMT by the antagonizing of EMT-promoting pathways. High degree of overlapping findings is supportive of the central role of the mevalonate pathway in cancer stem-like cells, but further studies are required to find the optimized chemical structure for the maximum abrogation of orchestrated EMT pathways.

All three compounds were revealed IC50 value around 51.96±7.15 microM in HN-5 cells which were significantly lower than observed IC50 for AGO1522, 121.93±3.66 microM (p=0.001). Significant increase expression of FAS, FASL and TRIAL were observed in the treated cells with or without pretreatment with zVAD. In the absence of pretreatment, treatment lead to the induction of apoptosis with a significant increase in caspase-3 gene expression and caspase-3 activity without a significant increase in expression or activity of caspase-9 and other components of the intrinsic apoptotic pathway. However, in the zVAD pretreated cells, necroptotic cell death with a significant increase in expression of RIP1, RIP3, and MLKL genes was observed Conclusion: The novel hybrid benzoxazole-coumarins effectively induce Caspase-3 dependent apoptosis in HN-5 cancer cells, but also could circumvent the blockage of apoptotic cell death by induction of necroptosis.