ONC201-DerivedTetrahydropyridopyrimidindiones asPowerful ClpP Protease Activators to Tackle Diffuse Midline Glioma

Pediatric diffuse intrinsic pontine glioma (DIPG), classified under diffuse midline glioma, is a deadly tumor, with no effective treatments. The human mitochondrial protease <i>h</i>ClpP is a potential DIPG therapeutic target, and this study describes the synthesis of two new series of tetrahydropyridopyrimidindiones (THPPDs) as <i>h</i>ClpP activators. Among the tested compounds, we have identified <b>36</b> (THX6) that shows a strong <i>h</i>ClpP activation (EC₅₀ = 1.18 μM) and good cytotoxicity in <b>ONC201</b>-resistant cells (IC₅₀ = 0.13 μM). Studying the oxidation mechanisms on cell membranes, the treatment of DIPG cells with <b>36</b> (THX6) causes a change in levels of fatty acids (PUFAs, MUFAs, and SFAs) compared to untreated cells and dysregulates the level of proteins involved in oxidative phosphorylation, biogenesis, and mitophagy that lead to a global collapse of mitochondrial integrity and function suggesting this as the mechanism through which <b>36</b> (THX6) accomplishes its antitumor activity in DIPG cell lines.