Design and Synthesis of Quinoxaline Hybrids as Modulators of HIF-1a, VEGF, and p21 for Halting Colorectal Cancer

A library of 16 3-benzyl-N ¹-substituted quinoxalin-2-ones was synthesized as N ¹-substituted quinoxalines and quinoxaline-triazole hybrids via click reaction. These compounds were tested for their anticancer activity via MTT assay on HCT-116 and normal colonocyte cell lines to assess their cytotoxic potentials and safety profiles. Overall, compounds 6, 9, 14, and 20 were found to be promising anticolorectal cancer agents; they exhibited remarkable cytotoxicity (IC₅₀ 0.05-0.07 μM) against HCT-116 cells within their safe doses (EC100) on normal colon cells. Their pronounced anticancer activities were observed as severe morphological alterations and shrinkage of the treated cancer cells. Besides, qRT-PCR analysis was conducted showing the potential of the promising hits to downregulate HIF-1a, VEGF, and BCL-2 as well as their ability to enhance the expression of proapoptotic genes p21, p53, and BAX in HCT-116 cells. In silico prediction revealed that most of our compounds agree with Lipinski and Veber parameters of rules, in addition to remarkable medicinal chemistry and drug-likeness parameters with no CNS side effects. Interestingly, docking studies of the compounds in the VEGFR-2' active site showed significant affinity toward the essential amino acids, which supported the biological results.