Synthesis and Evaluation of Novel Cholestanoheterocyclic Steroids as Anticancer Agents.

Modification of steroid molecules by introducing heterocyclic ring into the core structure of steroids has been utilized as an attractive approach for either cancer prognosis or diagnosis. Several new cholestanoheterocyclic steroids were synthesized, and analytical and spectral data proved the validity of the novel synthesized steroid derivatives. The cytotoxicity of synthesized compounds 3, 4, 5, 7, 9, 10, 13, 15b, and 16b was evaluated using human colorectal cancer HCT 116 and Caco-2, cervical cancer HeLa, hepatoma HepG2, and breast cancer MCF7 cell lines. Intriguingly, compound 13 has the highest cytotoxic effect when applied on the majority of cancer cells. In conclusion, compound 13 may be considered as a promising anticancer candidate against all cancer cell lines, because it recorded the lowest IC50 of the majority of the cancer cell lines used. Furthermore, a molecular docking study was employed to determine the binding modes against aromatase cytochrome P450 (CYP19), cyclin-dependent kinase 2 (CDK2), and B-cell lymphoma (BCL-2) proteins, which are major proteins involved in the pathogenesis of cancer. Molecular docking analyses revealed that compounds 13, 3, and 5 (free energy of binding = - 9.2, - 9.1, and - 9.0 kcal/mol, respectively) were the best docked ligand against aromatase CYP19; compounds 16b, 3, 9, and 10 (free energy of binding = - 9.6, - 9.3, and - 9.2 kcal/mol, respectively) were the best docked ligand against CDK2, while compounds 15b, 16b, and 13 (free energy of binding = - 9.1, - 9.0, and- 8.7 kcal/mol, respectively) were the best docked ligand against BCL2. In conclusion, compounds 3, 13, and 16b were the most promising compounds with the lowest IC50s against most of the tested cancer cell lines, and they displayed the lowest binding energies, critical hydrogen bonds, and hydrophobic interactions with the three molecular targets compared to other tested compounds.