Bimetallic junctions

The formation of voids through interdiffusion in bimetallic welded structures exposed to high operating temperatures is inhibited by utilizing an alloy of the parent materials in the junction of the parent materials or by preannealing the junction at an ultrahigh temperature. These methods are also used to reduce the concentration gradient of a hardening agent

Brafv600e and Ctbn1 Mutational Study in Rathke's Cleft Cysts

Aim: Rathke's cleft cysts and craniopharyngiomas tipically involve sellar region and their histogenetic relationship is still matter of debate. Clinical and histopathologic differentiation of cystic lesions from the sellar region, that is, craniopharyngiomas (CPs) and Rathke cleft cysts (RCCs), is challenging and has great importance with respect to variable clinical manifestation and adapted surgical treatment strategies in both entities. The recent acquisition that adamantinomatous and papillary craniopharyngiomas bear distinct molecular alterations i.e., β-catenin (CTNNB1) and BRAFv600 mutations respectively, has suggest to screen for such alteration a series of Rathke cyst to seek a possible relation with one of the two craniopharyngioma type. Methods: Seven Rathke's cleft cysts were analyzed for BRAF and CTNNB1 mutational status by sequencing and immunohistochemistry. Radiological, clinical and histological features were performed. Results: None of the 7 Rathke's cleft cysts harbor BRAFV600E mutation. No CTNNB1 mutation was found. Radiological, clinical and histological re-evaluation of the cases confirmed the diagnosis of Rathke's cleft cysts. Conclusion: BRAFV600E and CTNNB1 mutations appeared, as most reliable factor for the differentiation between purely cystic CPs and RCCs, whereas tumor location, tumor size, and radiological parameter of the tumor were less consistent parameters. This study again confirms that craniopharyngiomas (CPs) and Rathke cleft cysts (RCCs), are associated with distinct pathogenic pathways

Cytotoxicity effect of quinoin, type 1 ribosome-inactivating protein from quinoa seeds, on glioblastoma cells

Ribosome-inactivating proteins (RIPs) are found in several edible plants and are well characterized. Many studies highlight their use in cancer therapy, alone or as immunoconjugates, linked to monoclonal antibodies directed against target cancer cells. In this context, we investigate the cytotoxicity of quinoin, a novel type 1 RIP from quinoa seeds, on human continuous and primary glioblastoma cell lines. The cytotoxic effect of quinoin was assayed on human continuous glioblas-toma U87Mg cells. Moreover, considering that common conventional glioblastoma multiforme (GBM) cell lines are genetically different from the tumors from which they derive, the cytotoxicity of quinoin was subsequently tested towards primary cells NULU and ZAR (two cell lines established from patients’ gliomas), also in combination with the chemotherapeutic agent temozolomide (TMZ), cur-rently used in glioblastoma treatment. The present study demonstrated that quinoin (2.5 and 5.0 nM) strongly reduced glioblastoma cells’ growth. The mechanisms responsible for the inhibitory action of quinoin are different in the tested primary cell lines, reproducing the heterogeneous response of glioblastoma cells. Interestingly, primary cells treated with quinoin in combination with TMZ were more sensitive to the treatment. Overall, our data highlight that quinoin could represent a novel tool for glioblastoma therapy and a possible adjuvant for the treatment of the disease in combination with TMZ, alone or as possible immunoconjugates/nanoconstructs

Ageritin—The Ribotoxin-like Protein from Poplar Mushroom (Cyclocybe aegerita) Sensitizes Primary Glioblastoma Cells to Conventional Temozolomide Chemotherapy

Here, we propose Ageritin, the prototype of the ribotoxin-like protein family, as an adjuvant treatment to control the growth of NULU and ZAR, two primary human glioblastoma cell lines, which exhibit a pharmacoresistance phenotype. Ageritin is able to inhibit NULU and ZAR growth with an IC50 of 0.53 ± 0.29 µM and 0.42 ± 0.49 µM, respectively. In this study, Ageritin treatment highlighted a macroscopic genotoxic response through the formation of micronuclei, which represents the morphological manifestation of genomic chaos induced by this toxin. DNA damage was not associated with either the deregulation of DNA repair enzymes (i.e., ATM and DNA-PK), as demonstrated by quantitative PCR, or reactive oxygen species. Indeed, the pretreatment of the most responsive cell line ZAR with the ROS scavenger N-acetylcysteine (NAC) did not follow the reverse cytotoxic effect of Ageritin, suggesting that this protein is not involved in cellular oxidative stress. Vice versa, Ageritin pretreatment strongly enhanced the sensitivity to temozolomide (TMZ) and inhibited MGMT protein expression, restoring the sensitivity to temozolomide. Overall, Ageritin could be considered as a possible innovative glioblastoma treatment, directly damaging DNA and downregulating the MGMT DNA repair protein. Finally, we verified the proteolysis susceptibility of Ageritin using an in vitro digestion system, and considered the future perspective use of this toxin as a bioconjugate in biomedicine

Knock-Down of Mucolipin 1 Channel Promotes Tumor Progression and Invasion in Human Glioblastoma Cell Lines

Among cancers that affect the central nervous system, glioblastoma is the most common. Given the negative prognostic significance of transient receptor potential mucolipin 1 (TRPML1) channel reduction in patients with glioblastoma, as discussed in previous publications, the aim of the current study was to investigate the biological advantage of TRPML1 loss for glioma cells. Human glioblastoma primary cancer cells (FSL and FCL) and glioblastoma cell lines (T98 and U251) were used for that purpose. TRPML1 silencing in T98 cells induces defective autophagy, nitric oxide (NO) production, and cathepsin B-dependent apoptosis in the first 48 h and then apoptotic-resistant cells proliferate with a high growth rate with respect to control cells. In U251 cells, knock-down of TRPML1 stimulates NO generation and protein oxidation, arrests cell cycle at G2/M phase, and induces autophagy leading to cathepsin B-dependent senescence. Finally, in both cell lines, the long-term effects of TRPML1 silencing promote survival and invasion capacity with respect to control cells. Silencing of TRPML1 also affects the phenotype of glioblastoma primary cells. FSL cells show increased proliferation ability, while FCL cells enter into senescence associated with an increased invasion ability. In conclusion, although the molecular heterogeneity among different glioblastoma cell lines mirrors the intercellular heterogeneity in cancer cells, our data support TRPML1 downregulation as a negative prognostic factor in glioblastoma

The Early Growth Response Gene EGR-1 Behaves as a Suppressor Gene That Is Down-Regulated Independent of ARF/Mdm2 but not p53 Alterations in Fresh Human Gliomas.

EGR-1 is an immediate early gene with diverse functions that include the suppression of growth. EGR-1 is down-regulated many cancer cell types, suggesting a tumor suppressor role, and may critically involve the p53 pathway. The aim of this work was to measure the expression of EGR-1 and the p16/INK4a/ARF-Mdm2-p53 pathway status in fresh human gliomas. Thirty-one human gliomas with different grades of malignancy were investigated for Egr-1 mRNA and the protein expression, frequency, and spectrum of p53 gene mutations, mdm2 gene amplification, and p16/INK4a/ARF allele loss. The amplification of Mdm2 and the deletion of the p16/INK4a gene was found in 3 and 5 cases, respectively, whereas mutations of p53, including two novel mutations, were observed in 10 other cases. The three types of changes occurred strictly mutually exclusively, emphasizing that these genes operate in a common pathway critical to glioma progression. EGR-1 mRNA was significantly down-regulated in astrocytomas (14.7 +/- 5.1%) and in glioblastomas (33.6 +/- 10.0%) versus normal brain. Overall, EGR-1 mRNA was strongly suppressed (average, 15.2 +/- 13.9%) in 27 of 31 cases (87%), independent of changes in p16/INK4a/ARF and Mdm2; whereas 4 of 31 cases with residual EGR-1 expression as well as the highest EGR-1 variance segregated with p53 mutations. Immunohistochemical analyses confirmed the suppression of EGR-1 protein. These results indicate that EGR-1 is commonly suppressed in gliomas independent of p16/INK4a/ARF and Mdm2 and that suppression is less crucial in tumors bearing p53 mutations, and these results implicate an EGR-1 growth regulatory mechanism as a target of inactivation during tumor progression