الفهرس | Only 14 pages are availabe for public view |
Abstract The lung, colorectal and female breast cancers are the top three types of cancer in incidence and are responsible for one-third of the incidence and mortality of cancer. Although, the incidence and mortality brain and CNS cancers are rare but require difficult regimen of treatment. The mitotic spindle is one of the validated target in cancer chemotherapy. Well-known anti-proliferative agents, such as taxanes and vinca alkaloids, which target tubulin are clinically successful anticancer agents for certain types of cancer. However, these spindle poisons have certain limitations, such as resistance and toxicities, making it necessary to find other ways of targeting the mitotic spindle. A crucial family of motor proteins that has been shown to be vital for mitosis and that is developing as a target for chemotherapeutic intervention is the kinesin family. Mitotic kinesin Eg5 is a member of kinesin family that essential for bipolar spindle formation. The inhibition of Eg5 leads to the activation of the spindle checkpoint, mitotic arrest at G2/M phase and subsequent cell death in certain tumor cell lines. A series of thirty nine 3,4-dihydropyrimidine derivatives bearing the heterocyclic 1,3-benzodioxole moiety at position 4 in addition to different substituents at positions 1, 2, 3, 5 and 6 were designed, synthesized via multicomponent reaction of Biginelli type by cyclocondensation of aldehyde, urea or its derivatives and active methylene compounds and characterized by elemental analysis and the spectroscopic data (1H NMR, 13C NMR, and mass spectroscopy) and evaluated as inhibitors of Eg5 kinesin enzyme. The target compounds were screened for their cytotoxic activity towards 60 cancer cell lines according to national cancer institute (NCI), USA protocol at one dose. Out of thirty nine synthesized compounds, there were five compounds showed the best antitumor activity against most cell lines in single dose experiment among the synthesized compounds. Only one compound was selected by NCI (USA) to be subsequently tested in 5-doses mode and displayed high selectivity towards CNS cancer, prostate cancer and leukemia subpanel with selectivity ratios of 22.30, 15.38 and 12.56, respectively at GI50 level. Some representative compounds were assayed against kinesin enzyme with IC50 values ranged from 1.2 to 18.71 μM which were more potent than monastrol (IC50 = 20 μM). The most active compounds were evaluated against human embryonic kidney (HEK 293); a human normal cell line and exhibited lower toxicity towards HEK 293 in comparison to doxorubicin (DOX) as a reference drug (IC50 = 11.34 μM). DNA flow cytometric analysis was performed to measure the effect of two selected compounds on induction of cycle of NCI-522 cancer cell and SNB- 75 cancer cell in the presence of positive and negative controls. Cell cycle analysis of selected cancer cells showed cell cycle arrest at G2/M phase. Further, the assay of levels of active caspase-3 and caspase-9 was investigated to provoke apoptosis in MDA-MB-435 melanoma cell line and NCI-H522 lung cancer cell line. Treatment of these cell lines with selected compounds significantly increased the expression levels of active caspases 3 and 9 in comparison to the control. Molecular docking study was performed for selected target compounds along with the reference compound (monastrol) into the allosteric site of kinesin spindle protein 1Q0B to study the comparative differences in the binding interactions of these synthesized compounds at molecular level, explore the structure activity relationships and to explain the data obtained from the cytotoxicity activity. |