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Purpose@#Temozolomide is used in first-line treatment for glioblastoma. However, chemoresistance to temozolomide is common in glioma patients. In addition, mechanisms for the anti-tumor effects of temozolomide are largely unknown. Ferroptosis is a form of programmed cell death triggered by disturbed redox homeostasis, overloaded iron, and increased lipid peroxidation. The present study was performed to elucidate the involvement of ferroptosis in the anti-tumor mechanisms of temozolomide. @*Materials and Methods@#We utilized the CCK8 assay to evaluate cytotoxicity. Levels of lactate dehydrogenase (LDH), malondialdehyde (MDA), iron, and glutathione (GSH) were measured. Flow cytometry and fluorescence microscope were used to detect the production of reactive oxygen species (ROS). Western blotting, RT-PCR and siRNA transfection were used to investigate molecular mechanisms. @*Results@#Temozolomide increased the levels of LDH, MDA, and iron and reduced GSH levels in TG905 cells. Furthermore, we found that ROS levels and DMT1 expression were elevated in TG905 cells treated with temozolomide and were accompanied by a decrease in the expression of glutathione peroxidase 4, indicating an iron-dependent cell death, ferroptosis. Our results also showed that temozolomide-induced ferroptosis is associated with regulation of the Nrf2/HO-1 pathway. Conversely, DMT1 knockdown by siRNA evidently blocked temozolomide-induced ferroptosis in TG905 cells. @*Conclusion@#Taken together, our findings indicate that temozolomide may suppress cell growth partly by inducing ferroptosis by targeting DMT1 expression in glioblastoma cells.
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Purpose@#Temozolomide is used in first-line treatment for glioblastoma. However, chemoresistance to temozolomide is common in glioma patients. In addition, mechanisms for the anti-tumor effects of temozolomide are largely unknown. Ferroptosis is a form of programmed cell death triggered by disturbed redox homeostasis, overloaded iron, and increased lipid peroxidation. The present study was performed to elucidate the involvement of ferroptosis in the anti-tumor mechanisms of temozolomide. @*Materials and Methods@#We utilized the CCK8 assay to evaluate cytotoxicity. Levels of lactate dehydrogenase (LDH), malondialdehyde (MDA), iron, and glutathione (GSH) were measured. Flow cytometry and fluorescence microscope were used to detect the production of reactive oxygen species (ROS). Western blotting, RT-PCR and siRNA transfection were used to investigate molecular mechanisms. @*Results@#Temozolomide increased the levels of LDH, MDA, and iron and reduced GSH levels in TG905 cells. Furthermore, we found that ROS levels and DMT1 expression were elevated in TG905 cells treated with temozolomide and were accompanied by a decrease in the expression of glutathione peroxidase 4, indicating an iron-dependent cell death, ferroptosis. Our results also showed that temozolomide-induced ferroptosis is associated with regulation of the Nrf2/HO-1 pathway. Conversely, DMT1 knockdown by siRNA evidently blocked temozolomide-induced ferroptosis in TG905 cells. @*Conclusion@#Taken together, our findings indicate that temozolomide may suppress cell growth partly by inducing ferroptosis by targeting DMT1 expression in glioblastoma cells.
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<p><b>OBJECTIVE</b>To investigate EXT1 and EXT2 genes mutations in a family with hereditary multiple osteochondromas (HME).</p><p><b>METHODS</b>A four-generation family with HME from Linyi city of Shandong Province was studied. There were 6 affected individuals among the 17 family members. Physical examination and radiographical evaluations were carried out for all family members. Genomic DNA was extracted from peripheral venous blood and the samples were subjected to mutation screening by PCR of the coding regions of EXT1 and EXT2 genes.</p><p><b>RESULTS</b>The family has featured an autosomal dominant inheritance pattern. Sequencing of the EXT1 and EXT2 genes suggested the causative gene in this family was in linkage with the second exon of EXT2. A c.244delG mutation was detected, which has resulted in a frameshift mutation p.Asp81IlefsX30. The mutation was found in all of the 6 affected individuals but not in normal family members. And the mutation has co-segregated with the phenotype.</p><p><b>CONCLUSION</b>The mutation c.244delG in the EXT2 gene is the probably the cause of the disease in this family.</p>