The HL-60 cell line, derived from a patient with acute promyelocytic leukemia, proliferates continuously in suspension culture and consists predominantly (>90%) of promyelocytes. These cells can be induced to differentiate to morphologically and functionally mature granulocytes by incubation with a wide variety of compounds, including butyrate and hypoxanthine and polar planar compounds such as dimethyl sulfoxide and hexamethylene bisacetamide. We have now found that retinoic acid (all-trans-retinoic acid) induces differentiation (as measured morphologically and by the ability to reduce nitroblue tetrazolium) of HL-60 at concentrations as low as 1 nM.Maximal differentiation (approximately 90%) occurs at 1 MuM, a concentration 1/500th to 1/160,000th the concentrations of butyrate (0.5 mM) and dimethyl sulfoxide (160 mM) that promote a similar increase in differentiation. Continuous exposure to retinoic acid is necessary for optimal differentiation, with the percentage of mature cells in the culture directly related to the length of time of exposure to retinoic acid. Retinoic acid and 13-cis-retinoic acid are equally effective in inducing differentiation of , retinal, and retinyl acetate are approximately 1/1000th less potent. This study suggests that retinoids could provide a therapeutic tool in the treatment of acute myeloid leukemia, a disease that has been looked upon as primarily involving a block in myeloid differentiation, and indicates that retinoids, in addition to their well-characterized involvement in epithelial cell differentiation, may also be involved in the differentiation of certain hematopoietic cells.Retinoids (vitamin A and its natural and synthetic analogs) influence the normal differentiation of epithelium. Retinoid deficiency in rats leads to premalignant lesions in a wide variety of epithelial tissue that are reversed by the administration of retinoids (1). Retinoids inhibit carcinogenesis in vio (2, 3) and suppress malignant transformation in vitro (4,5). Certain of these compounds inhibit the growth of transformed cells (6, 7) and induce differentiation of mouse embryonal carcinoma cells in vitro (8-10). The antineoplastic effects of retinoids suggest that these compounds could be used therapeutically for the chemoprevention of cancer (11).The HL-60 cell line, derived from a patient with acute promyelocytic leukemia (12), proliferates continuously in suspension culture and consists predominantly of promyelocytes. These cells manifest a transformed phenotype, as shown by karyotypic abnormalities, continuous proliferation for over 3 years in culture, tumorigenicity in nude mice, and morphological, histochemical, and karyotypic similarity to the patient's leukemic cells (13). However, these cells can be induced to terminally differentiate to morphologically mature granulocytes by incubation with a wide variety of compounds, including butyrate, hypoxanthine, actinomycin D, and polar planar compounds such as dimethyl sulfoxide (Me2SO) and hexamethylene bisacetamide (HMBA) (14,15). More...

Several molecular subtypes of sporadic Creutzfeldt–Jakob disease have been identified and electroencephalogram and cerebrospinal fluid biomarkers have been reported to support clinical diagnosis but with variable utility according to subtype. In recent years, a series of publications have demonstrated a potentially important role for magnetic resonance imaging in the pre-mortem diagnosis of sporadic Creutzfeldt–Jakob disease. Magnetic resonance imaging signal alterations correlate with distinct sporadic Creutzfeldt–Jakob disease molecular subtypes and thus might contribute to the earlier identification of the whole spectrum of sporadic Creutzfeldt–Jakob disease cases. This multi-centre international study aimed to provide a rationale for the amendment of the clinical diagnostic criteria for sporadic Creutzfeldt–Jakob disease. Patients with sporadic Creutzfeldt–Jakob disease and fluid attenuated inversion recovery or diffusion-weight imaging were recruited from 12 countries. Patients referred as ‘suspected sporadic Creutzfeldt–Jakob disease’ but with an alternative diagnosis after thorough follow up, were analysed as controls. All magnetic resonance imaging scans were assessed for signal changes according to a standard protocol encompassing seven cortical regions, basal ganglia, thalamus and cerebellum. Magnetic resonance imaging scans were evaluated in 436 sporadic Creutzfeldt–Jakob disease patients and 141 controls. The pattern of high signal intensity with the best sensitivity and specificity in the differential diagnosis of sporadic Creutzfeldt–Jakob disease was identified. The optimum diagnostic accuracy in the differential diagnosis of rapid progressive dementia was obtained when either at least two cortical regions (temporal, parietal or occipital) or both caudate nucleus and putamen displayed a high signal in fluid attenuated inversion recovery or diffusion-weight imaging magnetic resonance imaging. Based on our analyses, magnetic resonance imaging was positive in 83% of cases. In all definite cases, the amended criteria would cover the vast majority of suspected cases, being positive in 98%. Cerebral cortical signal increase and high signal in caudate nucleus and putamen on fluid attenuated inversion recovery or diffusion-weight imaging magnetic resonance imaging are useful in the diagnosis of sporadic Creutzfeldt–Jakob disease. We propose an amendment to the clinical diagnostic criteria for sporadic Creutzfeldt–Jakob disease to include findings from magnetic resonance imaging scans.

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ABSTRACr A human leukemic cell line (designated H-1O0) has recently been established from the peripheral blood leukocytes of a patient with acute promyelocytic leukemia. This cell line displays distinct morphological and histochemical commitment towards myeloid differentiation. The cultured cells are predominantly promyelocytes, but the addition of dimethyl sulfoxide to the culture induces them to differentiate into myelocytes, metamyelocytes, and banded and segmented neutrophils. All 150 clones developed from the HLAO culture show similar morphological differentiation in the presence of dimethyl sulfoxide. Unlike the morphologically immature promyelocytes, the dimethyl sulfoxide-induced mature cells exhibit functional maturity as exemplified by hagocytic activity. A number of other compounds previously shown toinduce erythroid differentiation of mouse erythroleukemia (Friend) cells can induce analogous maturation of the myeloid HL-60 cells. The marked similarity in behavior of HL-O0 cells and Friend cells in the presence of these inducing agents suggests that similar molecular mechanisms are involved in the induction of differentiation of these human myeloid and murine erythroid leukemic cells. mented neutrophils. Although conditioned medium from a whole human embryo fibroblast strain was apparently required to initiate growth of the HL-60 cells (11), these cells, unlike human myeloid cells in our previous experience (12-14), do not require exogenous factor or conditioned medium for sustained growth. The cells have continuously proliferated and maintained distinct myeloid characteristics for over a year in suspension culture. Their morphological and histochemical myeloid characteristics are similar to those of the patient's uncultured leukemic blood cells, and the modal chromosome number of 44 found in the early passages of the HL-60 culture is the same as the modal chromosome number observed in fresh bone marrow obtained from the patient prior to chemotherapy (11). These findings, together with the ability of the cultured HL-60 cells to be tumorigenic in athymic nude mice (to be published elsewhere), indicate that the HL-60 cells are leukemic in origin.In the present study we show that after the addition of MeaSO and other polar compounds capable of inducing maturation in the above-mentioned rodent cell lines, there is a marked increase in the proportion of mature myeloid cells in the human HL-60 culture. Moreover, these morphologically mature cells, unlike the immature promyelocytes, are now capable of phagocytosis. Thus a differentiation-inducing effect of Me2SO and related compounds has now been demonstrated in human cells. The fact that these compounds can induce differentiation in such a variety of different rodent and human cell lines suggests that they may trigger differentiation through common mechanisms in a wide range of mammalian cells. MATERIALS AND METHODS

Using DNA microarrays together with quantitative proteomic techniques (ICAT reagents, two-dimensional DIGE, and MS), we evaluated the correlation of mRNA and protein levels in two hematopoietic cell lines representing distinct stages of myeloid differentiation, as well as in the livers of mice treated for different periods of time with three different peroxisome proliferative activated receptor agonists. We observe that the differential expression of mRNA (up or down) can capture at most 40% of the variation of protein expression. Although the overall pattern of protein expression is similar to that of mRNA expression, the incongruent expression between mRNAs and proteins emphasize the importance of posttranscriptional regulatory mechanisms in cellular development or perturbation that can be unveiled only through integrated analyses of both proteins and mRNAs. Molecular & Cellular Proteomics 3:960 -969, 2004.Genome-wide mRNA expression profiling by means of DNA microarrays has proven to be a powerful approach in characterizing the changes in biological processes such as disease states, developmental stages, and responses to drugs or genetic perturbations (1). However, DNA arrays measure only the changes at the mRNA level. Most biological functions are executed by the proteins rather than mRNAs. While the expression of many genes is controlled at the transcriptional level, other genes also employ posttranscriptional regulation processes involving mRNA stability, translation initiation, and protein stability. An important issue is the extent to which the changing expression patterns of mRNAs reflect corresponding changes in their cognate proteins. Recent advances in quantitative proteomics, especially the application of ICAT reagents in conjunction with MS, have made possible simultaneous quantitative comparison of hundreds of proteins between two complex mixtures (2). Integrated analyses of mRNA and protein expression data by concurrent measurement of both have revealed moderate to poor correlation in yeast and Halobacteria (3-5). Discordant expression of protein and mRNA was also observed in lung adenocarcinomas (6). However, these analyses examined only one aspect of a biological system, i.e. the steady-state levels of mRNAs and proteins. Another important aspect that concerns the kinetic process of perturbation and how the correlation of mRNA and protein evolves during this process was not addressed. Here, we evaluated the correlation of mRNA and protein expression in mammalian systems under two experimental conditions. In the first, we compared steady-state levels of mRNAs and proteins between two related cell lines representing distinct hematopoietic stages, i.e. multipotent myeloid precursors versus lineage-committed promyelocytic cells. In the second condition, we used a mouse model to demonstrate the kinetic changes in liver mRNA and protein levels in response to treatment with three different drugs. In both cases, we observed a moderate correlation between mRNA and protein levels with the expression of m...