Remarkably most of these molecules are also quite
Remarkably, most of these molecules are also quite effective in interfering with the proliferation of the drug-resistant cancer cell lines, with IC50 values ranging from 0.59 to 2.93 μM against MCF-7/ADR cells, and from 0.160 to 1.17 μM against NSCLC-resistant H1975 cells. Among these molecules, compound 7a possess the strongest ability to inhibit MCF-7/ADR Cap Firefly Luciferase sale (IC50 = 0.59 μM), while compound 7b, exhibited the highest inhibitory potency against H1975 cells (IC50 = 0.190 μM). These newly obtained FAK inhibitors provide a new insight to overcome the stubborn drug-resistance cancer cells.
In addition, the potent inhibitor 7a also has very low cytotoxicity toward the normal HPDEC cells (IC50 = 6.62 μM) and LO2 cells (IC50 = 3.70 μM). The data shown in Fig. 3 reveals that compound 7a markedly inhibited the proliferations of AsPC-1 cells with increasing drug concentration from 125 to 1000 nM, and treatment time from 24 to 72 h. The results presented in Fig. 4 revealed that 7a could induce striking nuclear condensation, membrane blebbing, nuclear fragmentation, and apoptotic bodies, all of which are characteristics of apoptotic programmed cell death. Thus, taken together, these findings indicate that compound 7a may serve as a new promising agent for the treatment of cancers that are hard to treat.
To investigate the effects of compound 7a on FAK activation and downstream signaling in AsPC-1 cells, the expression and activation of proteins involved in FAK mediated MEK pathways were assessed via immunoblotting analysis (Fig. 5) [32,33]. The analysis demonstrated that treatment with 7a significantly repressed FAK phosphorylation in a dose-dependent manner. For compound 7a, complete inhibition was achieved at a concentration of 50 nM for 72 h, while for TAE226, it was achieved at a concentration of 100 nM, which showed the superior anticancer potency of compound 7a. However, compound 7a produced little effect on the expression of MEK and ERK proteins, suggesting that compound 7a may interfere with other downstream signaling proteins of the FAK pathway. The extensive mechanism of action of the signaling pathway will be explored in our subsequent work.
Conclusion A new class of Car-pyrimidines were synthesized and biologically evaluated as potent FAK inhibitors. Two of them displayed equal anti-FAK enzymatic activity against FAK to the lead compound TAE226, with IC50 values of 5.17 nM (7a), and 2.58 nM (7f). In particular, compound 7a could also significantly block the proliferation of AsPC-1 (IC50 = 0.105 nM), BxPC-3 (IC50 = 0.090 nM), and MCF-7/ADR cells (IC50 = 0.59 nM). The Western blot analysis demonstrated that treatment with 7a significantly repressed FAK phosphorylation at a very low concentration in AsPC cells. In vivo antitumor efficacy using AsPC-1 cancer Xenograft mouse model showed that tumor growth was greatly inhibited by repeated oral administration of 7a. All these evaluations suggested that inhibitor 7a may serve as a promising preclinical candidate for treatment of stubborn cancer disease.
Acknowledgments We are grateful to the National Natural Science Foundation of Liaoning province (20180530066), the National Natural Science Foundation of China (No. 81603186, 81672945), the Research Fund of Higher Education of Liaoning province (LQ2017039, LQ2017008)for the financial support of this research.
Introduction Tumor metastasis, as opposed to primary tumor growth, is a major cause of cancer mortality [1,2]. Tumor metastasis is a complex, multi-step process by which tumor cells must first gain the ability to migrate away from the original tumor and enter either the bloodstream or the lymphatic system in a process known as intravasation . Next, the cancer cell must be able to attach to endothelium of blood or lymph vessels and enter the surrounding tissue, known as extravasation . Only a few of these tumor cells that undergo intravasation can survive in circulation, and successfully colonize distant tissues . Several components of the tumor stroma, such as modified extracellular matrix and cell adhesion molecules induced by local inflammation, play key roles in promoting cancer metastasis [4,5].