There is increasing evidence that lipid rafts may play important roles in brain neuronal cell functions including signal transduction. Meanwhile, the results suggesting possible presence of rafts in intracellular organelles such as mitochondria have been also reported. In this study, we compared proteins in raft-like structure of mitochondria to those of synaptosomal rafts and analyzed age-related alterations in protein in both mitochondrial and synaptosomal lipid rafts. A low density Triton X-100-insoluble fraction was prepared from cerebral cortical synaptosome and mitochondria of mouse and analyzed by two-dimensional (2-D) gel electrophoresis in combination with mass spectrometry. Co-localization of flotillin and cholesterol in Triton X-100-insoluble fraction of mitochondria was shown by Western blot analysis. Differential display of proteins using computer-aided image analysis revealed that the composition of protein in flotillin-rich Triton X-100-insoluble fraction of mitochondria was similar to that found in synaptosome. Several protein spots on 2-D gels varied in quantity depending on the age of the mouse, including the guanine nucleotide-binding protein G(O) alpha subunit, as identified by peptide mass fingerprinting.

抄録全体を表示

Resistance to chemotherapy is an obstacle to the successful treatment of acute myeloid leukemia (AML). Failure of therapeutic treatment may be due to the development of multidrug resistance (MDR), the mechanisms of which include upregulation of membrane-resident transporters which efflux chemotherapeutic drugs from tumor cells, as well as failure of cancer cells to undergo apoptosis in response to chemotherapy. We developed a quantitative reverse transcription PCR method for MDR1 and multidrug resistance-related protein 1 (MRP1) transcripts to evaluate drug resistance, and applied it to clinical samples. P-glycoprotein encoding MDR1 (P-gp) expression was determined by Western blot analysis, rhodamine 123 was used for functional study of P-gp protein, and sensitization of leukemic cells to drugs was quantified by methyl thiazolyl tetrazolium (MTT) assays. In this review, we cover current findings and suggest that the different methods for determining MDR and, in particular, discuss the efficacy of this quantitative analysis of MDR1 transcripts for the prediction of clinical drug resistance in acute leukemia.

抄録全体を表示