1. Academic Validation
  2. Levetiracetam enhances the temozolomide effect on glioblastoma stem cell proliferation and apoptosis

Levetiracetam enhances the temozolomide effect on glioblastoma stem cell proliferation and apoptosis

  • Cancer Cell Int. 2018 Sep 10;18:136. doi: 10.1186/s12935-018-0626-8.
Bianca Maria Scicchitano 1 Silvia Sorrentino 1 Gabriella Proietti 1 Gina Lama 1 Gabriella Dobrowolny 2 Angela Catizone 2 Elena Binda 3 Luigi Maria Larocca 4 Gigliola Sica 1
Affiliations

Affiliations

  • 1 1Istituto di Istologia ed Embriologia, Università Cattolica del Sacro Cuore, Fondazione Policlinico Universitario A. Gemelli IRCCS, Roma, Italia.
  • 2 2DAHFMO-Unit of Histology and Medical Embryology, Sapienza University of Rome, Via Scarpa 16, 00161 Rome, Italy.
  • 3 3ISBReMIT-Cancer Stem Cells Unit, IRCSS Casa Sollievo della Sofferenza, Viale Padre Pio 7, 71013 San Giovanni Rotondo, FG Italy.
  • 4 4Istituto di Anatomia Patologica, Università Cattolica del Sacro Cuore, Fondazione Policlinico Universitario A. Gemelli IRCCS, Roma, Italia.
Abstract

Background: Glioblastoma multiforme (GBM) is a highly aggressive brain tumor in which Cancer cells with stem cell-like features, called Cancer Stem Cells (CSCs), were identified. Two CSC populations have been previously identified in GBM, one derived from the GBM area called enhanced lesion (GCSCs) and the other one from the brain area adjacent to the tumor margin (PCSCs) that greatly differ in their growth properties and tumor-initiating ability. To date the most effective chemotherapy to treat GBM is represented by alkylating agents such as temozolomide (TMZ), whose activity can be regulated by histone deacetylases (HDACs) inhibitors through the modulation of O6-methylguanine-DNA methyltransferase (MGMT) expression. Levetiracetam (LEV), a relatively new antiepileptic drug, modulates HDAC levels ultimately silencing MGMT, thus increasing TMZ effectiveness. However, an improvement in the therapeutic efficacy of TMZ is needed.

Methods: Cell proliferation was investigated by BrdU cell proliferation assay and by Western Blot analysis of PCNA expression. Apoptosis was evaluated by Western Blot and Immunofluorescence analysis of the cleaved Caspase-3 expression. MGMT and HDAC4 expression was analyzed by Western Blotting and Immunofluorescence. Statistical analysis was performed using the Student's t test and Mann-Whitney test.

Results: Here we evaluated the effect of TMZ on the proliferation rate of the IDH-wildtype GCSCs and PCSCs derived from six patients, in comparison with the effects of other drugs such as etoposide, irinotecan and carboplatin. Our results demonstrated that TMZ was less effective compared to the other agents; hence, we verified the possibility to increase the effect of TMZ by combining it with LEV. Here we show that LEV enhances the effect of TMZ on GCSCs proliferation (being less effective on PCSCs) by decreasing MGMT expression, promoting HDAC4 nuclear translocation and activating apoptotic pathway.

Conclusions: Although further studies are needed to determine the exact mechanism by which LEV makes GBM stem cells more sensitive to TMZ, these results suggest that the clinical therapeutic efficacy of TMZ in GBM might be enhanced by the combined treatment with LEV.

Keywords

Cancer stem cells; Glioblastoma; Levetiracetam; MGMT; Temozolomide.

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