Pyrimidine-Derived Scaffolds Targeting VEGFR-2, EGFR, and HER-2: Synthesis, Anticancer/Immunomodulatory Evaluation,...

Following the common structural features of VEGFR-2, EGFR, and HER-2 kinase inhibitors, two newly synthesized series of 3,4-dihydropyrimidine 2(1H)-(thio)ones-5-carboxamide (2a-l) and thiouracil-5-sulfonyl derivatives (4a-e) were evaluated for anti-proliferative activity against colorectal (HCT-116) and breast (MCF-7) cancer cell lines. Among the designed series, Compounds 2h and 2l were the most potent derivatives across both tumor models, exhibiting IC₅₀ values of 23.3 and 30.9 μM (HCT-116), respectively, and 31.5 and 39.2 μM (MCF-7), respectively, compared to sorafenib (IC₅₀ = 8.8 and 11.6 μM, respectively). Interestingly, 2h and 2l displayed a favorable safety profile toward the normal human cell line WI-38, with IC₅₀ > 200 μM comparable to sorafenib (IC₅₀ = 192 μM). In vitro enzymatic assays, 2h and 2l derivatives emerged as potent multi-kinase inhibitors targeting VEGFR-2, EGFR, and HER-2 with IC₅₀ = 0.20, 0.21, and 0.19 μM, respectively, and IC₅₀ = 0.67, 0.53, and 0.40 μM, respectively, hence circumventing cancer resistance mechanisms. The most potent Compound 2h prompted apoptosis and necrosis at % G0-G1 phase in HCT-116 via the activation of caspase-3 and 8, with significant downregulation of anti-apoptotic protein Bcl-2. Additionally, Compound 2h markedly suppressed immunomodulatory proteins TNF-α and IL-6 levels by 80.9% and 88.2%, respectively, in comparison to dexamethasone (82.7% and 93.2%, respectively), which attenuates tumor-promoting inflammation, disrupting pro-survival signaling pathways and metastasis. In silico ADMET, toxicity, and molecular docking studies were performed; notably, the docking simulations generated an interesting hypothesis for potential direct binding to Bcl-2, an effect distinct from the experimentally observed downstream downregulation of its expression. The present results pave the way for further developing of 2h candidate as a multi-tyrosine kinases inhibitor toward colon cancer cells.