Synthetic and Naturally Occurring Heterocyclic Anticancer Compounds with Multiple Biological Targets

Design, synthesis, in vitro and in silico evaluation of indole-based tetrazole derivatives as putative anti-breast cancer agents

A series of new indole-tetrazole derivatives were designed and synthesized to develop potential anti-breast cancer agents. The compounds exhibited in vitro anti-proliferative activity against ER-α positive T-47D (IC50 = 3.82-24.43 μM), MCF-7 (IC50 = 3.08-22.65 μM), and ER-α negative MDA-MB-231 (IC50 = 7.69-19.4 μM) human breast cancer cell lines. Compounds 5d and 5f displayed significant anti-proliferative activity compared to bazedoxifene (IC50 = 14.23 ± 0.68 μM), with IC50 values of 10.00 ± 0.59 and 3.83 ± 0.74 μM, respectively, against the ER-α dominant T-47D cell line. Also, both compounds showed non-significant cytotoxicity against normal cells HEK-293. Further, the ER-α binding affinity of 5d and 5f was assessed through a fluorescence polarization-based competitive binding assay, where 5d and 5f have shown significant binding with IC50 = 5.826 and 110.6 nM, respectively, as compared to the standard drug bazedoxifene (IC50 = 339.2 nM). Western blot analysis confirmed that compound 5d reduced ER-α protein expression in T-47D cells, hindering its transactivation and signalling pathways. Additionally, a molecular docking study suggests that compounds 5d and 5f bind in such a fashion that induces conformational changes in the protein, culminating in their antagonistic effect. Pharmacokinetic profiles showed that the compounds possessed drug-like properties. Furthermore, molecular dynamics simulation studies establish the dynamic stability and conformational behaviour of the ER-α protein and ligand complex of both compounds. Additionally, 5d and 5f ensure biological feasibility as per their DFT analysis through HOMO-LUMO energy gap analysis. In conclusion, compounds 5d and 5f, exhibiting significant ER-α antagonistic activity, can act as potential lead compounds for anti-breast cancer therapies.

Synthesis of novel pyrimido[4,5-b]quinoline derivatives as dual EGFR/HER2 inhibitors as anticancer agents

A series of novel N-aryl-5-aryl-6,7,8,9-tetrahydropyrimido[4,5-b]quinolin-4-amines 4a-4l was synthesized as potential anticancer agents through Dimroth rearrangement reaction of intermediates 3a-3c. Pyrimido[4,5-b]quinolines 4a-4l showed promising activity against the Michigan Cancer Foundation-7 (MCF-7) cell line, compared with lapatinib as the reference drug. Compounds 4d, 4h, 4i, and 4l demonstrated higher cytotoxic activity than lapatinib, with IC50 values of 2.67, 6.82, 4.31, and 1.62 µM, respectively. Compounds 4d, 4i, and 4l showed promising epidermal growth factor receptor (EGFR) inhibition with IC50 values of 0.065, 0.116, and 0.052 µM, respectively. These compounds were subjected to human epidermal growth factor receptor 2 (HER2) inhibition and showed IC50 values of 0.09, 0.164, and 0.055 µM, respectively. Compounds 4d, 4i, and 4l are good candidates as dual EGFR/HER2 inhibitors. The most active compound, 4l, was subjected to cell-cycle analysis and induced cell-cycle arrest at the S phase. Compound 4l induced apoptosis 60-fold compared with control untreated MCF-7 cells. 4l can inhibit cancer metastasis. It reduced MCF-7 cell infiltration and metastasis by 45% compared with control untreated cells.

Synthesis of novel pyrimido[4,5-b]quinolines as potential anticancer agents and HER2 inhibitors

A series of N-arylpyrimido[4,5-b]quinolines 3a-e and 2-aryl-2,3-dihydropyrimido[4,5-b]quinoline-4(1H)-ones 5a-e was designed and synthesized as potential anticancer agents against breast cancer. Compounds 3e, 5a, 5b, 5d, and 5e showed promising activity against the MCF-7 cell line. Among them, compound 5b was the most active with IC50 of 1.67 μM. Compound 5b promoted apoptosis and induced cell cycle arrest at S phase. 5b increased the level of pro-apoptotic proteins p53, Bax, and caspase-7 and inhibited the anti-apoptotic protein Bcl-2. Furthermore, all the synthesized compounds were docked into the crystal structure of HER2 (PBD: 3 pp0). Compounds 3e, 5a, 5b, 5d, and 5e showed good energy scores and binding modes. Finally, Compound 5b was evaluated on the HER2 assay and revealed good inhibition with IC50 of 0.073 μM.

Docking and Molecular Dynamics Identify Leads against 5 Alpha Reductase 2 for Benign Prostate Hyperplasia Treatment

Steroid 5 alpha-reductase 2 (5αR-2) is a membrane-embedded protein that together with other isoforms plays a key role in the metabolism of steroids. This enzyme catalyzes the reduction of testosterone to the more potent ligand, dihydrotestosterone (DHT) in the prostate. Androgens, testosterone, and DHT play important roles in prostate growth, development, and function. At the same time, both testosterone and DHT have been implicated in the pathogenesis of benign prostate hyperplasia (BPH). Inhibition of the DHT formation, therefore, provides a therapeutic strategy that offers the possibility of preventing, delaying, or treating BPH. Currently, two steroidal drugs that inhibit 5αR-2, dutasteride and finasteride, have been approved for clinical use. These two come at a high cost and also portray undesirable sexual side effects which necessitate the need to find new chemotherapeutic alternatives for the disease. Based on the aforementioned, finasteride and dutasteride were subjected to scaffold hopping, fragment-based de novo design, molecular docking, and molecular dynamics simulations employing databases like ChEMBL, DrugBank, PubChem, ChemSpider, and Zinc15 in the identification of potential hits targeting 5αR-2. Altogether, ten novel compounds targeting 5αR-2 were identified with binding energies lower or comparable to finasteride and dutasteride, the main inhibitors for this target. Molecular docking and molecular dynamics simulations studies identify amino acid residues Glu57, Phe219, Phe223, and Leu224 to be critical for ligand binding and complex stability. The physicochemical and pharmacological profiling suggests the potential of the hit compounds to be drug-like and orally active. Similarly, the quality parameter assessments revealed the hits possess LELP greater than 3 implying their promise as lead-like molecules. The compounds A5, A9, and A10 were, respectively, predicted to treat prostate disorders with Pa (0.188, 0.361, and 0.270) and Pi (0.176, 0.050, and 0.093), while A8 and A9 were found to be associated with BPH treatment with Pa (0.09 and 0.127) and Pi (0.077 and 0.033), respectively. Structural similarity searches via DrugBank identified the drugs faropenem, acemetacin, estradiol valerate, and yohimbine to be useful for BPH treatment suggesting the de novo designed ligands as potential chemotherapeutic agents for treating this disease.

Bio-Oriented Synthesis and Molecular Docking Studies of 1,2,4-Triazole Based Derivatives as Potential Anti-Cancer Agents against HepG2 Cell Line

Triazole-based acetamides serve as important scaffolds for various pharmacologically active drugs. In the present work, structural hybrids of 1,2,4-triazole and acetamides were furnished by chemically modifying 2-(4-isobutylphenyl) propanoic acid (1). Target compounds 7a-f were produced in considerable yields (70-76%) by coupling the triazole of compound 1 with different electrophiles under different reaction conditions. These triazole-coupled acetamide derivatives were verified by physiochemical and spectroscopic (HRMS, FTIR, 13CNMR, and 1HNMR,) methods. The anti-liver carcinoma effects of all of the derivatives against a HepG2 cell line were investigated. Compound 7f, with two methyl moieties at the ortho-position, exhibited the highest anti-proliferative activity among all of the compounds with an IC50 value of 16.782 µg/mL. 7f, the most effective anti-cancer molecule, also had a very low toxicity of 1.190.02%. Molecular docking demonstrates that all of the compounds, especially 7f, have exhibited excellent binding affinities of -176.749 kcal/mol and -170.066 kcal/mol to c-kit tyrosine kinase and protein kinase B, respectively. Compound 7f is recognized as the most suitable drug pharmacophore for the treatment of hepatocellular carcinoma.

Structural insights into conformational stability and binding of thiazolo-[2,3-b] quinazolinone derivatives with EGFR-TKD and in-vitro study

Heterocyclic molecules are well-known drugs against various diseases including cancer. Many tyrosine kinase inhibitors including erlotinib, osimertinib, and sunitinib were developed and approved but caused adverse effects among treated patients. Which prevents them from being used as cancer therapeutics. In this study, we strategically developed heterocyclic thiazolo-[2,3-b]quinazolinone derivatives by an organic synthesis approach. These synthesized molecules were assessed against the epidermal growth factor receptor tyrosine kinase domain (EGFR-TKD) by in silico methods. Molecular docking simulations unravel derivative 17 showed better binding energy scores and followed Absorption, Distribution, Metabolism, Excretion, and Toxicity (ADMET) properties. The binding affinity displayed by synthetic congener and reference molecule erlotinib was found to be -8.26 ± 0.0033 kcal/mol and -7.54 ± 0.1411 kcal/mol with the kinase domain. Further, molecular dynamic simulations were conducted thrice to validate the molecular docking study and achieved significant results. Both synthetic derivative and reference molecule attained stability in the active site of the TKD. The synthetic congener and erlotinib showed free energy binding (ΔGbind) -102.975 ± 3.714 kJ/mol and -130.378 ± 0.355 kJ/mol computed by Molecular Mechanics Poison Boltzmann Surface Area (MM-PBSA) method. In addition, the motions of each sampled system including the Apo complex were determined by the principal component analysis and Gibbs energy landscape analysis. The in-vitro apoptosis study was performed using MCF-7 and H-1299 cancer cell lines. However, thiazolo-[2,3-]-quinazoline derivative 17 showed fair anti-proliferative activity against MCF-7 and H-1299. Further, the in-vivo study is necessary to determine the effectivity of the potent anti-proliferative, non-toxic molecule against TKD.