Design, synthesis, anticancer evaluation, and in silico ADMET analysis of novel thalidomide analogs as promising immunomodulatory agents

Abstract

Immunomodulatory medications like thalidomide and its analogs prevent the production of some proinflammatory cytokines linked to cancer. A new series of thalidomide analogs were designed and synthesized in order to develop potential antitumor immunomodulatory agents. The antiproliferative activities of the new candidates against a panel of three human cancer cell lines (HepG-2, PC3 and MCF-7) were assessed in comparison to thalidomide as a positive control. The obtained results showed the relative significant potency of 18f (IC₅₀ = 11.91 ± 0.9, 9.27 ± 0.7, and 18.62 ± 1.5 μM) and 21b (IC₅₀ = 10.48 ± 0.8, 22.56 ± 1.6, and 16.39 ± 1.4 μM) against the mentioned cell lines, respectively. These results were comparable to thalidomide (IC₅₀ = 11.26 ± 0.54, 14.58 ± 0.57, and 16.87 ± 0.7 μM, respectively). To see to what extent the biological properties of the new candidates are relative to those of thalidomide, the effects of 18f and 21b on the expression levels of TNF-α, CASP8, VEGF, and NF-κB P65 were evaluated. Significant reductions in the proinflammatory TNF-α, VEGF, and NF-κB P65 levels in HepG-2 cells were observed after exposure to compounds 18f and 21b. Furthermore, a sharp increase in CASP8 levels was detected. The obtained results revealed that 21b is of greater significance than thalidomide in TNF-α and NF-κB P65 inhibition. The in silico ADMET and toxicity studies showed that most of tested candidates have a good profile of drug-likeness and low toxicity potential.

Fig. 1. Reported thalidomide analogs having the same pharmacophoric features.

Fig. 2. Rationale of the work using thalidomide as lead compound.

Scheme 1. Synthesis of compounds 6a,b, and 9.

Scheme 2. Synthesis of compounds 12.

Scheme 3. Synthesis of compounds 18a–g.

Scheme 4. Synthesis of compounds 21a–c.

Fig. 3. SAR of the synthesized members.

Fig. 4. The effect of 21b on different phases of HepG-2 cell cycle.

Fig. 5. Apoptosis and necrosis rates of HepG2 cells treated with 21b compared to control and thalidomide.

Fig. 6. ADMET properties of the new derivatives and thalidomide.