Vitamin E D-α-Tocopheryl Polyethylene Glycol Succinate (TPGS) Provokes Cell Death in Human Neuroblastoma SK-N-SH Cells via a Pro-Oxidant Signaling Mechanism

Neuroblastoma (NB) is the most common neoplasm during infancy. Unfortunately, NB is still a lethal cancer. Therefore, innovative curative therapies are immediately required. In this study, we showed the prodeath activity of TPGS in human NB SK-N-SH cancer cells. NB cells were exposed to TPGS (10-80 mu M). We report for the first time that TPGS induces cell death by apoptosis in NB cells via a pro-oxidant-mediated signaling pathway. Certainly, H2O2 directly oxidizes DJ-1 cysteine (106)-thiolate into DJ-1 cysteine (106)-sulfonate, indirectly activates the transcription factors NF-kappaB, p.53, and c-JUN, induces the upregulation of mitochondria regulator proteins BAX/PUMA, and provokes the loss of mitochondrial membrane potential (Delta Psi(m))and the activation of caspase-3/AIF, leading to nuclear disintegration, demonstrated by cellular and biochemical techniques such as fluorescence microscopy, flow cytometry, and Western blot analysis. Since TPGS is a U.S. Food and Drug Administration (FDA)-approved pharmaceutical excipient, this molecule might be used in clinical trials for NB treatment.