The effect of novel synthetic semicarbazone- and thiosemicarbazone-linked 1,2,3-triazoles on the apoptotic markers, VEGFR-2, and cell cycle of myeloid leukemia.

Vascular Endothelial Growth Factor II (VEGFR-2) has been proved as a rational target in cancer therapy. Although currently prescribed VEGFR-2 inhibitors are showing potent antitumor activity, they are often causing serious unwanted effects, restricting their extensive use as chemotherapeutics. Herein, after analyzing the structures of the effective VEGFR-2 inhibitor molecules, we report the synthesis of a new set of semicarbazone- and thiosemicarbazone-linked 1,2,3-triazoles with expected potency of inhibiting the VEGFR-2 signaling. The design of new compounds considered maintaining the essential pharmacophoric features of sorafenib for effective binding with the receptor target. All compounds have been evaluated for their growth inhibition effect against a panel of sixty cancer cells at the National Cancer Institute. Leukemia cancer cells, especially HL-60 and SR, were shown to be the most sensitive to the cytotoxic effect of new compounds. Thiosemicarbazones 21, 26, and 30 exhibited the best activity against almost all tested cancer cells. Therefore, a set of subsequent in vitro biological evaluations has been performed to understand the mechanistic effect of these compounds further. They inhibited the VEGFR-2 with IC50 values of 0.128, 0.413, and 0.067 µM respectively compared with 0.048 µM of Sorafenib. The probable mechanistic effect of 30 has been further evaluated on a number of apoptotic and antiapoptotic markers including BAX, BCL2, caspase-3, and caspase-9. Results revealed the potential of the thiosemicarbazone-linked triazole 30 to induce both the early and the late apoptosis, elevate BAX/BCL2 ratio, induce caspase-3 & caspase-9, and arrest the HL-60 cell cycle at the G2/M and G0-G1 phases. Molecular docking of new semicarbazones and thiosemicarbazones into the proposed biological target receptor has also been performed. Results of docking studies proved the potential of new semicarbazone- and thiosemicarbazone-linked 1,2,3-triazoles to effectively bind with crucial residues of the VEGFR-2 binding pocket.

Apoptosis induction, PARP-1 inhibition, and cell cycle analysis of leukemia cancer cells treated with novel synthetic 1,2,3-triazole-chalcone conjugates.

Leukemia is a life-threatening nonepithelial malignant disorder that is characterized by uncontrolled growth of the hematopoietic cells. To date, there are still unmet needs for effective and less toxic medication for the management of this malignant tumor. Here, we report the synthesis of a new set of suggested anticancer molecules by joining the 1,2,3-triazole and chalcone privileged fragments in one scaffold to develop novel candidates in leukemia therapy. All the synthesized compounds have been screened for their cytotoxicity effect against a panel of 60 cancer cell lines at the National Cancer Institute. The leukemia cancer cells were found to be the most sensitive toward the effect of new molecules. A subsequent set of in vitro biological evaluation studies has been conducted on the most promising derivatives to identify their effect on such a cancer type. Four derivatives (11b, 11e, 11h, and 11j) showed excellent anticancer activity in the RPMI-8226 cells with IC50 values at low micromolar concentrations. Among these compounds, 11e was the most effective with an IC50 value of 3.17 µM (32-folds stronger than Staurosporine). The potential mechanistic effect of the latter has been further studied through the investigation of its potential effect on the cell cycle, PARP-1, and certain apoptotic and anti-apoptotic markers in the RPMI-8226 cells. Results of those studies revealed the potential of 11e to induce apoptosis through the upregulation of BAX, caspase-3, and caspase-9, and to arrest the cell cycle at the S phase.