Organoselenium-based Azomethines as Apoptosis Inducers in Colorectal Carcinoma via P53, BAX, Caspase-3, Caspase-6, and Caspase-9 Modulations

Background: Organoselenium (OSe) agents and Schiff bases have demonstrated immense potential in the pharmaceutical field due to their broad spectrum of medicinal activities. Methods: We herein report the antitumor activities of bis diselenide-based Schiff bases (3a-3c) derived from bis(4-aminophenyl)diselenide 2 and organoselenide-based Schiff bases (5a-c) derived from p-(methylselanyl)phenyl amine (4). The antitumor activity was estimated against fifteen cancer cell lines. Also, the growth inhibition percentage (GI%) of the Schiff bases tethered OSe compounds was evaluated against two normal cell lines, namely, human skin fibroblasts (HSF) and olfactory ensheathing cell line (OEC), to estimate the potential safety and selectivity. Furthermore, the cytotoxic inhibitory concentration 50 (IC₅₀) was assessed against the cancer cell lines with the most outstanding GI% using the SRB assay. Results: Compounds 3a, 3b, 3c, and 5a showed the lowest IC₅₀ values compared to those of doxorubicin (DOX) against HCT₁₁₆, HEPG2, A549, MDA-MB-468, and FaDu cancer cell lines, respectively, especially against the HCT₁₁₆ subtype, assuring their potential anticancer activity. On the other side, the apoptotic potentials of the most active compounds (3a, 3b, 3c, and 5a) were also evaluated for apoptosis-related genes (P53, BAX, caspases 3, 6, 8, and 9, MMP2, MMP9, and BCL-2). Interestingly, compounds 3a, 3b, 3c, and 5a upregulated P53, BAX, and caspases 3, 6, 8, and 9 by (2.66, 2.26, 2.44, and 2.57)-, (1.62, 1.52, 1.37, and 1.47)-, (1.87, 1.75, 2.02, and 1.75)-, (1.96, 1.74, 2.06, and 2.30)-, (4.25, 3.78, 3.53, and 3.96)-, and (2.04, 1.72, 1.90, and 1.63)-fold change, respectively. Furthermore, MMP2, MMP9, and BCL-2 were downregulated by (0.39, 0.51, 0.33, and 0.28)-, (0.29, 0.32, 0.37, and 0.41)-, and (0.42, 0.35, 0.29, and 0.38)-fold-change, upon treatment with compounds 3a, 3b, 3c, and 5a, respectively, assuring the apoptotic potentials. Finally, molecular docking also greatly recommends the potential activity of the examined candidates (especially 3a and 3c) against the GSTP1 receptor as a recommended mechanism for their antitumor activity. Conclusion: Our findings point to significant anticancer activities of Schiff bases tethered OSe agents, suggesting their promising potential for development as effective anticancer drugs.