Discovery of new VEGFR-2 inhibitors based on bis([1, 2, 4]triazolo)[4,3-<i>a</i>:3',4'-<i>c</i>]quinoxaline derivatives as anticancer agents and apoptosis inducers

Abstract

Herein, a new wave of bis([1, 2, 4]triazolo)[4,3-<i>a</i>:3',4'-<i>c</i>]quinoxaline derivatives have been successfully designed and synthesised. The synthesised derivatives were biologically investigated for their cytotoxic activities against HepG2 and MCF-7. Also, the tested compounds were further examined <i>in vitro</i> for their VEGFR-2 inhibitory activity. The most promising derivative <b>23j</b> was further investigated for its apoptotic behaviour in HepG2 cell lines using flow cytometric and western-plot analyses. Additional <i>in-silico</i> studies were performed to predict how the synthesised compounds can bind to VEGFR-2 and to determine the drug-likeness profiling of these derivatives. The results revealed that compounds <b>23a</b>, <b>23i</b>, <b>23j</b>, <b>23l</b>, and <b>23n</b> displayed the highest antiproliferative activities against the two cell lines with IC₅₀ values ranging from 6.4 to 19.4 µM. Furthermore, compounds <b>23a</b>, <b>23d</b>, <b>23h</b>, <b>23i</b>, <b>23j</b>, <b>23l</b>, <b>23 m</b>, and <b>23n</b> showed the highest VEGFR-2 inhibitory activities with IC₅₀ values ranging from 3.7 to 11.8 nM, comparing to sorafenib (IC₅₀ = 3.12 nM). Moreover, compound <b>23j</b> arrested the HepG2 cell growth at the G2/M phase and induced apoptosis by 40.12% compared to the control cells (7.07%). As well, such compound showed a significant increase in the level of caspase-3 (1.36-fold), caspase-9 (2.80-fold), and BAX (1.65-fold), and exhibited a significant decrease in Bcl-2 level (2.63-fold).