Somatic homozygous loss of SH2B3, and a non-Robertsonian translocation t(15;21)(q25.3;q22.1) with NTRK3 rearrangement, in an adolescent with progenitor B-cell acute lymphoblastic leukemia with the iAMP21.

Intrachromosomal amplification of chromosome 21 (iAMP21) occurs in ∼2% of B-cell acute lymphoblastic leukemia (ALL) and is considered to confer a poor prognosis. The relapse risk is associated with therapy intensity, suggesting that other somatic mutations may influence iAMP21-ALL prognosis. This abnormality is characterized by multiple copies of the RUNX1 gene in chromosome 21 and appears to arise through multiple breakage-fusion bridge cycles and chromothripsis. Rob(15;21) or a ring chromosome 21 have been associated with an increased risk for iAMP21-ALL, suggesting that constitutional genetic abnormalities may also drive leukemogenesis. Here we describe homozygous deletion of the SH2B3 gene, chromothripsis of chromosome 21, and a non-Robertsonian somatic t(15;21)(q25.3;q22.1) with NTRK3 gene rearrangement in an adolescent with iAMP21-B-ALL. Molecular cytogenetic studies detected iAMP21 with aCGH analysis revealing further genomic imbalances. The RT-qPCR analysis detected elevated expression levels of RUNX1 (68-fold) and reduced expression of CDK6 (0.057-fold). Studies with constitutive cells collected from mouth swabs showed that SH2B3 biallelic deletion was a somatic alteration occurring during clonal evolution. The identification of novel secondary genetic changes was valuable to discuss sporadic iAMP21 leukemogenic mechanisms. For the first time, we show a t(15;21)(q25.3;q22.1) with NTRK3 rearrangement in an adolescent with iAMP21-ALL.

Short infusion of paclitaxel imbalances plasmatic lipid metabolism and correlates with cardiac markers of acute damage in patients with breast cancer.

PURPOSE: Although paclitaxel-based chemotherapy is widely used for treating breast cancer, paclitaxel therapy has been associated with several adverse effects. Such adverse effects have primarily been associated with long-term regimens, but some acute effects are being increasingly reported in the literature. In this context, the present study analyzed the systemic proteomic profiles of women diagnosed with breast cancer at the first cycle of short paclitaxel infusion (n = 30). Proteomic profiles thus obtained were compared with those of breast cancer patients without chemotherapy (n = 50), as well as with those of healthy controls (n = 40). METHODS: Plasma samples were evaluated by label-free LC-MS to obtain systemic proteomic profiles. Putative dysregulated pathways were identified and validated by in silico analysis of proteomic profiles. RESULTS: Our results identified 188 proteins that were differentially expressed in patients who received a single short paclitaxel infusion when compared to patients who did not receive the infusion. Gene ontology analysis indicated that the cholesterol pathway may be dysregulated by paclitaxel in these patients. Validation analysis showed that paclitaxel treatment significantly reduced plasma high-density lipoprotein levels and increased plasma hydroperoxide levels when compared to breast cancer patients without chemotherapy. Furthermore, augmented C-reactive protein and creatine kinase fraction MB were found to be significantly higher in paclitaxel-treated patients in comparison with healthy controls. CONCLUSIONS: Taken together, these data suggest that a single dose of short paclitaxel infusion is sufficient to trigger significant alterations in lipid metabolism, which puts breast cancer patients at risk for increased incidence of cardiovascular disease.

Accurate monitoring of promoter gene methylation with high-resolution melting polymerase chain reaction using the ABCB1 gene as a model.

Multidrug resistance is the major cause of cancer chemotherapy failure. This phenotype is mainly due to the overexpression of the human ABCB1 gene. Several studies have shown that the transcriptional regulation of this gene is complex. Yet, the impact of this transcriptional regulation has not been well studied in a clinical setting. The acquired expression of ABCB1 is associated with the genomic instability of cancer cells. This includes the occurrence of mutational events that alter chromatin structures through epigenetic modifications such as promoter methylation. Therefore, it is important to introduce new clinical methods to monitor the methylation status of ABCB1 and determine its association with gene expression in order to be able to predict response to therapies. The high-resolution melting (HRM) method has emerged as a highly accurate and sensitive method to quantify methylation status at specific sites of DNA. Here, we established HRM parameters to evaluate the promoter methylation status of the ABCB1 gene. Our study is the first to standardize the HRM dissociation curve to evaluate ABCB1 gene methylation. The association between ABCB1 methylation status and gene expression in established cancer cell lines shows that this method is accurate and reliable.

Stability of human mesenchymal stem cells during in vitro culture: considerations for cell therapy.

Ex vivo expansion and manipulation of human mesenchymal stem cells are important approaches to immunoregulatory and regenerative cell therapies. Although these cells show great potential for use, issues relating to their overall nature emerge as problems in the field. The need for extensive cell quantity amplification in vitro to obtain sufficient cell numbers for use, poses a risk of accumulating genetic and epigenetic abnormalities that could lead to sporadic malignant cell transformation. In this study, we have examined human mesenchymal stem cells derived from bone marrow, over extended culture time, using cytogenetic analyses, mixed lymphocyte reactions, proteomics and gene expression assays to determine whether the cultures would retain their potential for use in subsequent passages. Results indicate that in vitro cultures of these cells demonstrated chromosome variability after passage 4, but their immunomodulatory functions and differentiation capacity were maintained. At the molecular level, changes were observed from passage 5 on, indicating initiation of differentiation. Together, these results lead to the hypothesis that human mesenchymal stem cells cultures can be used successfully in cell therapy up to passage 4. However, use of cells from higher passages would have to be analysed case by case.

BCR-ABL-mediated upregulation of PRAME is responsible for knocking down TRAIL in CML patients.

Tumor necrosis factor-related apoptosis-inducing ligand-TNFSF10 (TRAIL), a member of the TNF-α family and a death receptor ligand, was shown to selectively kill tumor cells. Not surprisingly, TRAIL is downregulated in a variety of tumor cells, including BCR-ABL-positive leukemia. Although we know much about the molecular basis of TRAIL-mediated cell killing, the mechanism responsible for TRAIL inhibition in tumors remains elusive because (a) TRAIL can be regulated by retinoic acid (RA); (b) the tumor antigen preferentially expressed antigen of melanoma (PRAME) was shown to inhibit transcription of RA receptor target genes through the polycomb protein, enhancer of zeste homolog 2 (EZH2); and (c) we have found that TRAIL is inversely correlated with BCR-ABL in chronic myeloid leukemia (CML) patients. Thus, we decided to investigate the association of PRAME, EZH2 and TRAIL in BCR-ABL-positive leukemia. Here, we demonstrate that PRAME, but not EZH2, is upregulated in BCR-ABL cells and is associated with the progression of disease in CML patients. There is a positive correlation between PRAME and BCR-ABL and an inverse correlation between PRAME and TRAIL in these patients. Importantly, knocking down PRAME or EZH2 by RNA interference in a BCR-ABL-positive cell line restores TRAIL expression. Moreover, there is an enrichment of EZH2 binding on the promoter region of TRAIL in a CML cell line. This binding is lost after PRAME knockdown. Finally, knocking down PRAME or EZH2, and consequently induction of TRAIL expression, enhances Imatinib sensibility. Taken together, our data reveal a novel regulatory mechanism responsible for lowering TRAIL expression and provide the basis of alternative targets for combined therapeutic strategies for CML.

LLL-3, a STAT3 inhibitor, represses BCR-ABL-positive cell proliferation, activates apoptosis and improves the effects of Imatinib mesylate.

PURPOSE: The chimeric protein BCR-ABL, a constitutively active protein-tyrosine kinase, triggers downstream signalling proteins, such as STAT3, ultimately resulting in the survival of myeloid progenitors in BCR-ABL-positive leukemias. Here, we evaluated the effect of LLL-3, an inhibitor of STAT3 activity, on cell viability and its addictive effects with Imatinib mesylate (IM) treatment in BCR-ABL-positive cells. METHODS: Viability of cell lines was determined using the WST-1 assay in response to drug treatment, either LLL-3 alone or in conjunction with IM. Annexin V-FITC/PI staining, sub-G1 DNA content and Caspase-3/7 activation assays were performed to evaluate apoptosis. RESULTS: LLL-3 treatment decreased cell viability, triggered apoptosis and activated Caspases-3/7 in K562 cells. LLL-3 increases IM treatment to inhibited cell viability and activation of apoptosis in BCR-ABL-positive cell lines. CONCLUSIONS: LLL-3 reduced cell viability and induced apoptosis in K562 cells. Moreover, the observed addictive effects of co-treatment with IM and LLL-3 suggest this combination has therapeutic potential.

Evaluation of trehalose and sucrose as cryoprotectants for hematopoietic stem cells of umbilical cord blood.

Bone marrow transplantation (BMT) is a therapeutic procedure that involves transplantation of hematopoietic stem cells (HSC). To date, there are three sources of HSC for clinical use: bone marrow; mobilized peripheral blood; and umbilical cord blood (UCB). Depending on the stem cell source or type of transplantation, these cells are cryopreserved. The most widely used cryoprotectant is dimethylsulfoxide (Me(2)SO) 10% (v/v), but infusion of Me(2)SO-cryopreserved cells is frequently associated with serious side effects in patients. In this study, we assessed the use of trehalose and sucrose for cryopreservation of UCB cells in combination with reduced amounts of Me(2)SO. The post-thawed cells were counted and tested for viability with Trypan blue, the proportion of HSC was determined by flow cytometry, and the proportion of hematopoeitic progenitor cells was measured by a colony-forming unit (CFU) assay. A solution of 30mmol/L trehalose with 2.5% Me(2)SO (v/v) or 60mmol/L sucrose with 5% Me(2)SO (v/v) produced results similar to those for 10% (v/v) Me(2)SO in terms of the clonogenic potential of progenitor cells, cell viability, and numbers of CD45(+)/34(+) cells in post-thawed cord blood cryopreserved for a minimum of 2 weeks. Thus, cord blood, as other HSC, can be cryopreserved with 1/4 the standard Me(2)SO concentration with the addition of disaccharides. The use of Me(2)SO at low concentrations in the cryopreservation solution may improve the safety of hematopoietic cell transplantation by reducing the side effects on the patient.

Expression of dorsal-ventral genes during early development of Rhynchosciara americana embryos

The establishment of dorsal-ventral polarity in Drosophila is a complex process which involves the action of maternal and zygotically expressed genes. Interspecific differences in the expression pattern of some of these genes have been described in other species. Here we present the expression of dorsal-ventral genes during early embryogenesis in the lower dipteran Rhynchosciara americana. The expression of four genes, the ventralizing genes snail (sna) and twist (twi) and the dorsalizing genes decapentaplegic (dpp) and zerknüllt (zen), was investigated by whole-mount in situ hybridization. Sense and antisense mRNA were transcribed in vitro using UTP-digoxigenin and hybridized at 55°C with dechorionated fixed embryos. Staining was obtained with anti-digoxigenin alkaline phosphatase-conjugated antibody revealed with NBT-BCIP solution. The results showed that, in general, the spatial-temporal expression of R. americana dorsal-ventral genes is similar to that observed in Drosophila, where twi and sna are restricted to the ventral region, while dpp and zen are expressed in the dorsal side. The differences encountered were subtle and probably represent a particular aspect of dorsal-ventral axis determination in R. americana. In this lower dipteran sna is expressed slightly later than twi and dpp expression is expanded over the lateral ectoderm during cellular blastoderm stage. These data suggest that the establishment of dorsal-ventral polarity in R. americana embryos follows a program similar to that observed in Drosophila melanogaster.

Chromosomal alterations associated with evolution from myelodysplastic syndrome to acute myeloid leukemia.

Several studies have demonstrated the prognostic value of cytogenetic analysis in MDS both for survival and progression to AML. However it is unknown which are the numerical or structural abnormalities required for leukemic transformation. In this report we studied clinically and cytogenetically 127 patients: 125 with primary MDS and two with AML with a previous history of MDS. Thirty-one patients (24%) showed evolution of the disease during the follow-up study. Chromosomal abnormalities found at diagnosis in patients that progressed toward AML included: del(5)(q15), +6, del(6)(q21), t(5;8)(q32;q22),-7, del(7)(q22), der(7)t(1;7)(q10;p10), t(7;11)(p15;p15), +8, del(11)(q23), del(12p), del(3)(q21), del(20)(q12) and complex karyotypes. Eight of these patients were studied cytogenetically during transformation and showed acquisition of chromosomal alterations involving dup(1q), +8, del(11)(q23), and translocations between chromosomes 1 and 8 or 7 and 17. In addition we also observed gain of ploidy and monosomy 21. These results suggest that chromosomal alterations during evolution of the disease include special chromosome gains or abnormalities of chromosomes 1, 7, 8, 11 and 17 with involvement of ETV-1, Hox-A9, Pax 4, MLL genes besides a putative gene mapped at 17q25. We also applied the International Prognostic Scoring System (IPSS) to 114 patients, excluding those submitted to allogeneic bone marrow transplant. Our patients were classified into four distinct risk groups. The analysis of risk groups presented by 27 patients who showed evolution of the disease revealed 18 at the high risk group and four at the intermediate-2 group. From the intermediate-1 risk group only five patients showed evolution of the disease. Three of these patients evolved from RA to RAEB with gain of a del(11)(q23) or an expansion of a del(12)(p12) clone. Our results suggest that some chromosomal alterations are responsible for each step in the evolution of the disease. As the pathway of evolution is not unique it has been very difficult to define what genetic alteration comes first. However from several results in the literature and our own, it seems that some chromosomal alterations may predict the evolution of the disease and are correlated with short survival, as for example the trisomy of chromosome 8, and might be incorporated in the high risk group in the IPSS. This score system has been proved to be useful for predicting survival and evolution from MDS to AML.

Complex karyotype and N-RAS point mutation in a case of acute megakaryoblastic leukemia (M7) following a myelodysplastic syndrome.

The development of acute megakaryoblastic leukemia (ANLL-M7) following myelodysplastic syndrome (MDS) has been described only in a few reports, and the mutations necessary for this transformation are still unknown. In this study, we describe a case of ANLL-M7 with a previous history of MDS presenting a complex karyotype 46,XX, t(4;11)(q21;q23),del(5)(q13q33),t(12;13)(p13;q21) and N-RAS point mutation. During MDS, the patient showed a hypercellular myelogram with dysplasia of the three myeloid lineages and the clinical symptoms characteristic of the 5q- syndrome. During the follow-up, we observed the appearance of two additional subclones, one with an isochromosome 17q and another with polyploidy. The presence of an isochromosome 17q in one subclone and polyploidy in another is probably due to the genetic instability generated by the malignant transformation.

Correlation of N-ras point mutations with specific chromosomal abnormalities in primary myelodysplastic syndrome.

A cytogenetic and N-ras point mutation study was done in patients with primary myelodysplastic syndrome (MDS) from Rio de Janeiro, Brazil, in order to evaluate the progression of preleukemic states to overt leukemia. Cytogenetic analysis was performed in 50 patients with MDS and clonal chromosomal abnormalities were detected in 19 (38%) of them. Patients with refractory anemia (RA) or with ringed sideroblasts (RARS) presented normal karyotypes or single abnormalities as del(5q) or -Y, while patients in more advanced states as RA with excess of blasts (RAEB), RAEB in transformation (RAEB-t) and chronic myelomonocytic leukemia (CMML) showed complex karyotypes and single abnormalities involving chromosomes 7 or 8, which were related to poor prognosis and elevated risk of transformation to acute myeloid leukemia (AML). The frequency of ras activation was studied in these 50 patients with MDS. Samples of bone marrow were screened for oncogenic point mutations by DNA amplification followed by oligonucleotide hybridization analysis (PCR-ASO) at codon 12 of N-ras proto-oncogene. We detected N-ras point mutations in 21 patients (42%). Progression from MDS to AML was observed in 9 patients (18%). The correlation analysis between N-ras point mutations and specific chromosomal abnormalities indicated that although mutated N-ras was found in cells with del(5q) and monosomy 7, cells with those abnormalities and normal N-ras were also identified. Otherwise trisomy of chromosome 8 showed a correlation with N-ras point mutations and in all cases, patients showed progression of MDS to AML during the follow-up study. MDS comprises a heterogeneous group of hematopoietic disorders and probably several steps are implicated in the evolution to AML. In this work we suggest that one possible pathway of leukemogenesis in MDS includes N-ras point mutations in association with trisomy of chromosome 8.

Translocation 11;14 in three children with acute lymphoblastic leukemia of T-cell origin.

Clinical, karyotypic, immunophenotypic, and molecular profiles of three TALL cases carrying a t(11;14) are discussed and compared with data in the literature. As previously reported, t(11;14)(p13;q11) was associated in one patient with a TALL profile of intermediate stage of maturation (CD7+, CD4+, CD8+). However, the same translocation was found to be present in another patient with a more immature, pro-TALL profile (CD7+, CD4-, CD8-). Both patients showed molecular rearrangements of the TCR beta chain gene. A third patient, with a very immature pro-TALL profile (CD34+, CD7+, CD4-, CD8-), carrying a t(11;14)(p15;q11), showed molecular rearrangements of the TCR beta and gamma chain genes, while the IgH chain genes were in germline configuration. Our data indicate that t(11;14) can also be present in TALLs of more immature stages of intrathymic development; the significant factor determining the clinical behavior of TALLs is apparently related more to cell differentiation than to the presence of this chromosome rearrangement.

Translocation of CD3D gene in an acute myeloid leukemia (M5) with t(11;17)(q23;21).

Cytogenetic studies in patients with acute leukemia showed structural abnormalities on chromosome 11 at band q23 in five cases. Four of these had acute lymphoblastic leukemia (ALL) associated with t(4;11)(q21;q23) and one case had acute nonlymphoblastic leukemia (ANLL) (M5) associated with t(11;17)(q23;q21). We examined the CD3D and c-ets-1 genes in the t(11;17)(q23;q21) patient to ascertain any association between them and the chromosome change. In situ hybridization results showed that unlike in other studied cases with rearrangements of 11q23, the CD3D gene in the t(11;17)(q23;21) is transposed to the der(17) chromosome, providing evidence for a different breakpoint in the 11q23 region.