Piperidine and valproic acid hybrid compound (F2S4-p-VPA) outperforms methotrexate as anti-proliferative and cells migration inhibition

Glioblastoma and triple-negative breast cancer (TNBC) pose significant challenges in treatment due to their invasive nature and propensity for metastasis. Methotrexate (MTX) is a common chemotherapeutic agent; however, it has limited efficacy owing to its low aqueous solubility and cytostatic rather than cytotoxic effects. Valproic acid (VPA) has been used as chemotherapeutic agent, but with low potency. In this study, two novel VPA derivatives (F2S4-<i>p</i>-VPA and F3S4-<i>m</i>-VPA) were designed, chemically synthesized, and evaluated <i>in vitro</i>. These compounds contain tertiary amines as pharmacophore groups reminiscent of methotrexate. Cytotoxicity, migration, assays were conducted on glioblastoma (LN-18, U373) and breast cancer (MDA-MB-231) cell lines, using fibroblast (3T3-L1; non-cancer cells) as a control. Apoptosis (LN-18 and MDA-MB-231), cell cycle arrest and Bax and Bcl2 assays were carried out on LN-18 cells. Physicochemical properties of the compounds were assessed using <i>in silico</i> predictions. Results showed that F2S4-<i>p</i>-VPA exhibited better cytotoxicity than F3S4-<i>m</i>-VPA on both LN-18 (IC₅₀ = 112 μM) and MDA-MB-231 (IC₅₀ = 142 μM) cell lines, while demonstrating reduced cytotoxicity in 3T3-L1 cells. F2S4-<i>p</i>-VPA inhibited cell migration, outperforming MTX. Moreover, F2S4-<i>p</i>-VPA induced the highest rate of apoptosis in LN-18 cell, and produce the cell cycle arrest in the S and G2/M phase, showing a Bax/Bak-independent propapoptotic effect suggesting other mechanisms of cell death. Also, these novel compounds possess superior physicochemical properties to MTX and VPA. These results suggest that F2S4-<i>p</i>-VPA warrants further investigation <i>in vivo</i> and may serve as structural scaffold for the development of novel compounds for the treatment of these aggressive cancers.