Abstract
A novel set of 2-cyanoacrylamides linked to ethyl 1,3-diphenylpyrazole-4-carboxylates moiety were synthesized and elucidated by different spectroscopic tools. In vitro cytotoxic assay was carried out against different cell lines (Hct(116), A(549), MDA-MB231, and HFB4). Ethyl 5-(2-cyano-3-(furan-2-yl)acrylamido)-1,3-diphenylpyrazole-4-carboxylate 5 achieved the potent cytotoxic effect toward all tested cancer cell lines especially colon cancer (HCT116) with IC50 value (30.6 mu g/ml) relative to the lead compound 3 and the standard positive control 5-FU. Additionally, it exhibited less toxic effect toward the normal human melanocytes (HFB4) cell line. Compound 5 was theoretically investigated and compared for its binding affinity to a model of protein markers relative to the lead compound 3 using two different molecular docking programs. More investigations were performed in an attempt to find out the molecular mechanism of this novel compound inside colon cancer cells, as real time PCR analysis, Elisa assay, flow cytometry, and morphological characterizations using TEM and SEM tools. Herein, we showed that compound 5 interferes with the intrinsic pathway of apoptosis at the mitochondrial level in response to an apoptogenic stimulus as cytochrome c, caspase-9 and caspases-3 which were triggered by our novel compound 5. All molecular investigations proved that intrinsic apoptotic pathway of colorectal carcinoma was strongly initiated by the effect of compound 5 through upregulation of mitochondrial apoptosis related genes as (Caspase-3, caspase-9, BAX, P-53, and cytochrome-c) and down-regulated anti-apoptotic proteins (BCL2, MMP1, CDK4, and VEGFR). Further studies proved cell cycle arrest of HCT116 cell lines at G2/M phase after treatment. In addition, our data revealed that our novel efficiently damage the genomic DNA of colorectal cells involving P-53 dependent mechanism using DPA assay. Sever morphological and ultrastructural changes were detected in colorectal cells treated by compound 5 compared to control using both scanning electron microscopy (SEM) and transmission electron microscopy (TEM).