Cancer is often associated with an aberrant increase in tubulin and microtubule activity required for cell migration, invasion, and metastasis. A new series of fatty acid conjugated chalcones have been designed as tubulin polymerization inhibitors and anticancer candidates. These conjugates were designed to harness the beneficial physicochemical properties, ease of synthesis, and tubulin inhibitory activity of two classes of natural components. New lipidated chalcones were synthesized from 4-aminoacetophenone via N-acylation followed by condensation with different aromatic aldehydes. All new compounds showed strong inhibition of tubulin polymerization and antiproliferative activity against breast and lung cancer cell lines (MCF-7 and A549) at low or sub-micromolar concentrations. A significant apoptotic effect was shown using a flow cytometry assay that corresponded to cytotoxicity against cancer cell lines, as indicated by a 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide assay. Decanoic acid conjugates were more potent than longer lipid analogues, with the most active being more potent than the reference tubulin inhibitor, combretastatin-A4 and the anticancer drug, doxorubicin. None of the newly synthesized compounds caused any detectable cytotoxicity against the normal cell line (Wi-38) or hemolysis of red blood cells below 100 μM. It is unlikely that the new conjugates described would affect normal cells or interrupt with cell membranes due to their lipidic nature. A quantitative structure-activity relationship analysis was performed to determine the influence of 315 descriptors of the physicochemical properties of the new conjugates on their tubulin inhibitory activity. The obtained model revealed a strong correlation between the tubulin inhibitory activity of the investigated compounds and their dipole moment and degree of reactivity.
The immune system is essential for the defense against infections and is critically implicated in various disorders, including immunodeficiency, autoimmunity, inflammation and cancer. The current study includes a new design of palmitoylated derivatives of thioglycolic acids (PTGAs) capable of triggering innate immune responses. The new series were accessible through a three-step synthetic route, including N-palmitoylation, Claisen-Schmidt condensation and thia-Michael addition. Their structures were elucidated using different 1D and 2D NMR spectroscopic techniques and their purity was confirmed by elemental analysis. The most active PTGAs induced a 12-26-fold increase in the expression of TNF-α and IL-1β mRNA and triggered a marked release of NO in isolated macrophages. These levels were comparable to the responses elicited by heat-killed E. coli and S. aureus. The position of the palmitamide chain and aryl substitution had a significant effect on the TNF-α and IL-1β mRNA expression and NO release. Simulations of molecular dockings showed that the new PTGA derivatives occupy the same TLR2/TLR6 heterodimer active binding site of the microbial diacylated lipoproteins. The new immunomodulators may have a profound impact on various clinical disorders associated with dysfunctional innate immunity.