Breast cancer is the most common type of diagnosed malignancies and the second leading cause of cancer death in women around the world [4]. Triple-negative breast cancer (TNBC) is characterized by the aggressive nature and lack of targeted therapies, which results in very limited treatment options [5]. Protein kinases are responsible for regulating different cellular functions, such as proliferation, cell cycle, apoptosis, motility, differentiation. Many studies have shown a causal role of protein kinase dysregulations or mutations in different human diseases, including cancer [1]. Over 25 kinase inhibitors are approved as anticancer drugs [2]. One of them is sunitinib, which is used to treat kidney cancer and gastrointestinal stromal tumors [3].
The aim of our study was to evaluate the anticancer activity of new sunitinib analogues on TNBC cell line MDA-MB-231.
Materials and methods. Experiments were performed on human cell line MDA-MB-231. 17 kinase inhibitors, which are sunitinib analogues, have been tested. These analogues were synthesized at the University of Cagliari, Italy, and their synthesis and characterization was published [6]. The effect of kinase inhibitors on cell viability was evaluated by MTT assay after 72 hours of incubation. First, we selected the most active kinase inhibitors that reduced cell viability up to 5% or less. Then the EC50 values of the most active compounds were established and compared to the sunitinib activity. Compound activity on breast cancer cell ability to migrate was examined using single cell tracking assay. This experiment was performed on a special imaging dish with a grid. Cells were seeded at a low concentration in the dish, to get 50-70 cells in total on a grid area. Cell were allowed to attach overnight, and then the solutions with tested compounds in a fresh medium were added. Images of the migrating cells were taken at one-hour intervals for 8 hours by using an inverted microscope. Single cells were tracked and the cell migration distance was measured. Then the average cell migration velocity was calculated.
Results. Kinase inhibitors 1, 6, 7, 8 and 17 were the most active ones. Among tested compounds, the compound 1 possessed the greatest effect on cell viability (EC50 value after 72 h on MDA-MB-231 was 73.61 ± 5.77 μM). Most of the other compounds reduced cancer cell viability at the concentrations ranging from 170 to 600 nM. All tested sunitinib analogues were more active than sunitinib. Also, tested compounds reduced the MDA-MB-231 cell migration. The compound 6, one of the most active ones, inhibited breast cancer cell migration by about 28% compared to the control.
Conclusions. Tested kinase inhibitors possess anticancer activity on triple-negative breast cancer cell line. They reduce the viability and inhibit migration of cells, and may be worthy for further studies.