Search

TP53 mutation is associated with various hematological malignancies and immunohistochemistry of p53 has been used as a simple method to establish the presence of a TP53 mutation. Since the significance of p53 expression is controversial in myelodysplastic syndrome (MDS) patients treated with azacitidine (Aza), we analyzed the prevalence of p53 expression as a prognostic factor in 60 MDS patients treated with Aza. To assess p53 expression, immunohistochemical analyses of bone marrow clot sections were performed. Overall survival (OS) was significantly lower in p53-positive patients compared with p53-negetive patients (59% vs. 85% at 12 months; P = 0.006). Multivariate analysis demonstrated that p53-positive was a significant prognostic factor for OS along with poor cytogenetics. Here, we propose a new prognostic index to make short-term prognoses of MDS patients in the era of Aza treatment; high: p53-positive and poor cytogenetics, low: p53-negative and absence of poor cytogenetics, and intermediate: the others. OS was significantly different among the three groups according to this index (Low 92%, Intermediate 65% and High 27% at 12 months; P < 0.0001). In conclusion, p53 expression was a significant prognostic factor in MDS patients treated with Aza. In combination with cytogenetic abnormalities, it is possible to make short-term prognoses. [ABSTRACT FROM AUTHOR]

Abstract: Mitochondrial dysfunction caused by mutations in mitochondrial DNA (mtDNA) is related to a variety of diseases including MELAS and NARP syndromes. However, little is known about the intracellular responses induced by mtDNA mutations. In order to identify genes whose expression is altered as a result of the presence of mtDNA mutations, DNA microarray analysis was performed using human 143B osteosarcoma cells harboring 3243A>G [tRNA-Leu (UUR)] and 8993T>G [ATPase6 Leu156Arg] mtDNA mutations associated with MELAS and NARP syndromes (2SD and NARP3-1 cybrid cells), respectively. We found that mRNA and protein levels of ATF4, CHOP and ASNS were upregulated in 2SD and NARP3-1 cells as compared with parental cells. Reporter assays demonstrated that transcription of CHOP and ASNS genes was upregulated through the AARE (amino acid regulatory element) and NSRE-1 (nutrient-sensing response element-1) enhancer elements to which ATF4 binds, respectively. Furthermore, knockdown of ATF4 by RNA interference reduced CHOP and ASNS transcription in 2SD and NARP3-1 cells. These results suggest that the presence of mtDNA mutations elicits upregulation of CHOP and ASNS genes through the elevation of ATF4 expression and its binding to the AARE and NSRE-1, respectively. [Copyright &y& Elsevier]

Abstract: Pyruvate treatment was found to alleviate clinical symptoms of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome and is highly promising therapeutic. Using capillary electrophoresis time-of-flight mass spectrometry (CE-TOFMS), we measured time-changes of 161 intracellular and 85 medium metabolites to elucidate metabolic effects of pyruvate treatment on cybrid human 143B osteosarcoma cells harboring normal (2SA) and MELAS mutant (2SD) mitochondria. The results demonstrated dramatic and sustainable effects of pyruvate administration on the energy metabolism of 2SD cells, corroborating pyruvate as a metabolically rational treatment regimen for improving symptoms associated with MELAS and possibly other mitochondrial diseases. [Copyright &y& Elsevier]