Design and synthesis of multitarget triazinoindole derivatives with potent antiproliferative activity: Targeting EGFR, SIRT1, MDM2, Hsp90, PI3K, p53, and caspase-9

Driven by the urgent need for novel anticancer agents capable of overcoming limitations associated with conventional therapies, a new series of Benzyl-5H-[1,2,4]triazino[5,6-b]indoles derivatives bearing flexible pyrazole or pyrazoline moieties were designed, synthesized, and evaluated for antiproliferative efficacy. Most of the synthesized compounds demonstrated notable cytotoxicity compared to the reference compound inauhzin (INZ). Specifically, compounds 4, 10, 11, and 12 exhibited potent activity against A549 lung cancer cells, with IC₅₀ values of 7.39 μM, 3.17 μM, 0.82 μM, and 5.38 μM, respectively, outperforming INZ (IC₅₀ = 8.97 μM). Against Caco-2 colorectal cancer cells, compounds 4, 5, and 10 displayed IC₅₀ values of 2.35 μM, 3.28 μM, and 2.63 μM, respectively, compared to INZ (IC₅₀ = 3.64 μM).

To elucidate the potential mechanisms underlying the anticancer activity of the most active compounds, a comprehensive set of assays was conducted, including cell cycle analysis, apoptosis evaluation, and quantification of key molecular targets such as EGFR, SIRT1, MDM2, Hsp90, PI3K, p53, and caspase-9. These biomarkers are intricately interconnected within cellular signaling pathways, whereby inhibition of EGFR and PI3K suppresses proliferative signaling, downregulation of SIRT1 and MDM2 leads to p53 activation, and subsequent induction of caspase-9-mediated apoptosis and cell cycle arrest. Notably, most of the tested compounds demonstrated promising results in modulating these targets, which supports their potential as effective anticancer agents. Additionally, selected compounds showed excellent binding to the target sites when docked into the active domains of EGFR, Hsp90, PI3K, SIRT1, and MDM2.