Design, synthesis, in vitro anticancer, molecular docking and SAR studies of new series of pyrrolo[2,3-d]pyrimidine derivatives

The current study involves the design and synthesis of a newly synthesized pyrrolo[2,3-d]pyrimidine derivatives to contain chlorine atoms in positions 4 and 6 and trichloromethyl group in position 2 using microwave technique as a new and robust approach for preparation of this type of pyrrolo[2,3-d]pyrimidine derivatives. The chemical structure of the synthesized pyrrolo[2,3-d]pyrimidine derivatives 3-19 was well-characterized using spectral and elemental analyses as well as single-crystal X-ray diffraction. All compounds were tested in vitro against seven selected human cancer cell lines, namely, MCF7, A549, HCT116, PC3, HePG2, PACA2 and BJ1 using MTT assay. It was found that compounds 14a, 16b and 18b were the most active toward MCF7 with IC50 (1.7, 5.7, and 3.4 μg/ml, respectively) relative to doxorubicin (Dox.) (26.1 μg/ml). Additionally, compound 17 exerted promising cytotoxic effects against HePG2 and PACA2 with IC50 (8.7 and 6.4 μg/ml, respectively) relative to Dox. (21.6 and 28.3 μg/ml, respectively). The molecular docking study confirmed our ELISA result which showed the promising binding affinities of compounds 14a and 17 against Bcl2 anti-apoptotic protein. At the gene expression level, P53, BAX, DR4 and DR5 were up-regulated, while Bcl2, Il-8, and CDK4 were down-regulated in 14a, 14b and 18b treated MCF7 cells. At the protein level, compound 14b increased the activity of Caspase 8 and BAX (18.263 and 14.25 pg/ml) relative to Dox. (3.99 and 4.92 pg/ml, respectively), while the activity of Bcl2 was greatly decreased in 14a treated MCF7 (2.4 pg/ml) compared with Dox. (14.37 pg/ml). Compounds 14a and 14b caused cell cycle arrest at the G1/S phase in MCF7. Compounds 16b and 18b induced the apoptotic death of MCF7 cells. In addition, the percentage of fragmented DNA was increased significantly in 14a treated MCF7 cells.