Ferrocenyl-Substituted Curcumin Derivatives as Potential SHP-2 Inhibitors for Anticolorectal Cancer: Design, Synthesis and <i>In Vitro</i> Evaluation

A panel of ferrocenyl-substituted curcumin derivatives has been designed and synthesized as protein tyrosine phosphatase proto-oncogene SHP-2 inhibitors. Antiproliferative activities of the synthesized compounds were tested against colorectal cancer cell lines (including RKO, SW480, and CT26). Compound <b>3f</b> showed excellent activities against the tested cell lines with IC₅₀ values of 5.72, 3.71, and 1.42 μM. The cytotoxicity of compound <b>3f</b> was investigated on human normal colon epithelial cell line NCM460 with IC₅₀ values of 929 μM compared to curcumin with IC₅₀ values of 431 μM. The Western blot analysis approved that the expression level of SHP-2 in the CT26 and SW480 cell lines after being treated with <b>3f</b> was decreased, meanwhile it also affected the SHP-2 in tumor-associated macrophages (THP-1 and RAW264.7), which may support the suggested mechanism of <b>3f</b> as an SHP-2 inhibitor. Besides, <b>3f</b> could also inhibit the activation of the PI3K-Akt pathway in SW480 and CT26 cell lines and the tumor microenvironment (TME) by reducing the expression of PI3K and Akt proteins. Some cytokines (Arg-1, TGF-β, and IL-10) and chemokines (chemokine receptors and CC and CXC chemokine subfamilies) in the TME were also inhibited by <b>3f</b>. Finally, <b>3f</b> could increase the expression level of cell cycle-related and mitophagy-related proteins p27, PINK1, and Parkin and decrease the expression level of CDK1 and Cyclin-D1 proteins in CT26 and SW480 cells, which proved that <b>3f</b> could inhibit the proliferation of CRC cells through multiple pathways. Molecular docking studies against ALDH1 (PDB ID: 5ABM) revealed the good binding modes of the newly synthesized compounds.