Dual EGFR and telomerase inhibitory potential of new triazole tethered Schiff bases endowed with apoptosis: design, synthesis, and biological assessments.

Many cancers have displayed resistance to chemotherapeutic drugs over the past few decades. EGFR has emerged as a leading target for cancer therapy via inhibiting tumor angiogenesis. Besides, studies strongly suggest that blocking telomerase activity could be an effective way to control the growth of certain cancer cells. Based on the fact that multi-target design rationale can afford candidates with greater treatment effectiveness. Besides, it was evidenced that inhibition of human telomerase enhances the effect of some tyrosine kinase inhibitors. So, in the current work, we aimed to design and synthesize novel 1,2,3-triazole-tethered Schiff bases (5a-l) to act as dual EGFR and telomerase inhibitors. Growth inhibition (GI)% was conducted for the synthesized compounds using a panel of eleven cancer cell lines as well as two normal cell lines. Interestingly, compound 5e displayed the highest mean GI% (76.78%) among the investigated compounds surpassing the mean GI% of the reference drug doxorubicin (65.79%). In addition, compound 5g displayed notably the lowest IC₅₀ values (13.31, 13.31, 12.62, and 31.19 μM) for the four utilized cancer cell lines HNO97, HCT116, A375, and HEPG2, respectively. Interestingly, the investigated compounds exhibited significant inhibitory potential to EGFR and telomerase protein expression; in particular, compound 5g recorded inhibitory potentials of 3.45 and 1.31 ng mL^-1, respectively. Hence, protein expression of the apoptosis-related proteins was carried out for compound 5g. Pro-apoptotic proteins (caspases 3, 8, and 9) were upregulated by 1.35, 1.55, and 1.51-fold change, respectively. Meanwhile, the anti-apoptotic proteins (CDK-2, CDK-4, and CDK-6) were downregulated by 2.91, 2.01, and 9.15-fold change, respectively, ensuring the apoptotic potential of compound 5g. Accordingly, compound 5g was selected for further investigation of its effects on cell cycle progression in A375 cancer cells. Obviously, compound 5g prompted cell cycle arrest at the G0-G1 phase. Additionally, the investigated compounds showed eligible pharmacokinetic profiles with feasible oral bioavailability. Consequently, the synthesized compounds can be treated as lead multi-target anticancer ligands for future optimization.