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.

The MLL recombinome of acute leukemias in 2013.

Chromosomal rearrangements of the human MLL (mixed lineage leukemia) gene are associated with high-risk infant, pediatric, adult and therapy-induced acute leukemias. We used long-distance inverse-polymerase chain reaction to characterize the chromosomal rearrangement of individual acute leukemia patients. We present data of the molecular characterization of 1590 MLL-rearranged biopsy samples obtained from acute leukemia patients. The precise localization of genomic breakpoints within the MLL gene and the involved translocation partner genes (TPGs) were determined and novel TPGs identified. All patients were classified according to their gender (852 females and 745 males), age at diagnosis (558 infant, 416 pediatric and 616 adult leukemia patients) and other clinical criteria. Combined data of our study and recently published data revealed a total of 121 different MLL rearrangements, of which 79 TPGs are now characterized at the molecular level. However, only seven rearrangements seem to be predominantly associated with illegitimate recombinations of the MLL gene (≈ 90%): AFF1/AF4, MLLT3/AF9, MLLT1/ENL, MLLT10/AF10, ELL, partial tandem duplications (MLL PTDs) and MLLT4/AF6, respectively. The MLL breakpoint distributions for all clinical relevant subtypes (gender, disease type, age at diagnosis, reciprocal, complex and therapy-induced translocations) are presented. Finally, we present the extending network of reciprocal MLL fusions deriving from complex rearrangements.

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.