[en] Purpose: We investigated the molecular mechanisms underlying the cytotoxic effect of Temozolomide (TMZ) in both O⁶-methylguanine-DNA methyl transferase (MGMT) depleted as well as undepleted glioblastoma cell lines. Since TMZ is used in clinics in combination with radiotherapy, we also studied the effects of TMZ in combination with ionising radiation (IR). Methods: Cell colony-forming ability was measured using a clonogenic assay. Cell cycle analysis and apoptosis were evaluated by Flow Cytometry (FCM). Proteins involved in cell cycle control were detected by Western blot and co-immunoprecipitation assays. Results: Our data showed that TMZ, independent of MGMT expression, inhibited glioblastoma cell growth via an irreversible G₂ block in MGMT depleted cells or the induction of apoptosis in MGMT normal expressing cells. When TMZ was administered in combination with IR, apoptosis was greater than observed with either agent separately. This TMZ-induced apoptosis in the MGMT expressing cells occurred through Akt/Glycogen-Synthase-Kinase-3ß (GSK3β) signalling and was mediated by Myelocytomatosis (c-Myc) oncoprotein. Indeed, TMZ phosphorylated/activated Akt led to phosphorylation/inactivation of GSK3β which resulted in the stabilisation of c-Myc protein and subsequent modulation of the c-Myc target genes involved in the apoptotic processes. Conclusion: c-Myc expression could be considered a good indicator of TMZ effectiveness. (authors)

[en] Choroid plexus carcinoma is a rare primary brain neoplasm arising from epithelial differentiated tissue, originating from the choroids plexus of the ventricles and, in 90% of the cases, in the lateral and fourth ventricles. This neoplasm is seen mainly in children and reported infrequently in adults. The treatment of choroid plexus carcinoma is based on scarce evidence in literature. We report a rare case of an adult woman affected by a choroid plexus tumour and a discussion on the therapeutic management of this uncommon adult malignancy