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Exosomes derived from solid tumour cells are involved in immune suppression, angiogenesis and metastasis; however, the role of leukaemia-derived exosomes has less been investigated. Hence, changes in immune response-related genes and human T cells apoptosis co-incubated with exosomes isolated from patients' pre-B cell acute lymphoblastic leukaemia were evaluated in this in vitro study. Vein blood sample was obtained from each newly diagnosed acute lymphoblastic leukaemia (ALL) patient prior any therapy. ALL serum exosomes were isolated by ultrafiltration and characterized using Western blotting and transmission electron microscopy. Exosomes were then co-incubated with T lymphocytes and the gene expressions, as well as functions of human T cells were quantified by qRT-PCR. Apoptosis and caspase-3 and caspase-9 protein expression were also evaluated by flowcytometry and Western blotting analysis, respectively. Exosomes isolated from ALL patients affected T lymphocytes and elevated the apoptosis. Moreover, these exosomes altered the T cells profile into regulatory type by increasing the expression of FOXP3 and Tregs-related cytokines, including TGF-B and IL-10. The expression level of Th17-related transcription factors (RoR gamma t) and interleukins (IL-17 and IL-23) decreased after this treatment. According to our findings, exosomes derived from ALL patients' sera carry immunosuppressive molecules, indicating the possible effect of exosomes as liquid biomarkers for cancer staging. The authors would acknowledge the stem cell research center at Tabriz University of Medical Sciences (TUOMS), Tabriz, Iran, for their great help. This work was financially supported by Tabriz University of Medical Sciences [63611 as grant number].

Conjugated linoleic acid (CLA) exhibits isomer-specific effects on transepithelial calcium (Ca) transport as well as on cell growth in human intestinal-like Caco-2 cells. However, the molecular mechanisms of action are still unclear. Therefore, this study used a transcriptomic approach to help elucidate the molecular mechanisms underlying such isomer-specific effects. Caco-2 cells were treated with 80 µmol/L linoleic acid (control), 80 µmol/L trans-10, cis-12 CLA, or 80 µmol/L cis-9, trans-11 CLA for 12 d. Ca transport was measured radio-isotopically. RNA was isolated from the cells, labeled, and hybridized to the Affymetrix U133 2.0 Plus arrays (n = 3). Data and functional analysis was preformed using Bioconductor. Using a minimum fold-change criterion of 1.6 and a false discovery rate criterion of P-value 0.05, trans-10, cis-12 CLA altered the expression of 918 genes, whereas, cis-9, trans-11 CLA had no effect on gene expression. Gene ontology analysis revealed that trans-10, cis-12 CLA strongly modulated a number of processes inherently related to carcinogenesis, such as cell cycle, cell proliferation, and DNA metabolism. Trans-10, cis-12 CLA, but not cis-9, trans-11 CLA, increased transepithelial Ca transport in Caco-2 cells, which corresponded to changes in molecular mediators of paracellular (including claudin 2 and 4) and transcellular (calbindin D9k and vitamin D receptor) Ca transport. This microarray-based study highlighted a number of gene expression patterns of relevance to 2 important intestinal processes (carcinogenesis and Ca transport), which were modulated by trans-10, cis-12 CLA. These may help our mechanistic understanding of the role of CLA in promoting gut function and health.

Despite the presence of many therapeutic regimens like imatinib and other tyrosine kinase inhibitors, the development of resistance, intolerance, and side effects makes chronic myeloid leukemia (CML) therapy challenging. Thus, there is a need to discover novel drugs for CML patients. In this study, we attempted to assess apigenin, a common plant dietary flavonoid, in terms of its cytotoxic, apoptotic, and cytostatic effects on imatinib-sensitive and resistant Philadelphia-positive CML cells. We analyzed apigenin's effects on cell proliferation, apoptosis, caspase-3 activity, loss of mitochondrial membrane potential, and cell cycle progression in K562 and K562/IMA3 cells. Furthermore, we described genes and gene networks that are modulated in CML in response to apigenin. Results of our study revealed that apigenin has cytotoxic and apoptotic effects on both cell types. We also displayed that apigenin induced G2/M arrest in K562 cells while arresting K562/IMA3 cells in S phase especially at the highest apigenin concentration. The expression analysis identified a set of genes that were regulated by apigenin in K652 and K562/IMA3 cells. Association of modulated genes with biological functional groups identified several networks affected by apigenin including cell survival, proliferation, cell death, cell cycle, and cell signalling pathways., NCI NIH HHS (P30 CA016672)

Palmitic acid is known to be apoptotic for nervous cells but no data are available on membrane lipidome transformations occurring during its supplementation, although membrane lipids are clearly involved in the apoptotic signaling cascade. NB100 neuroblastoma cells were supplemented with palmitic acid and membrane fatty acids were isolated, derivatized and analysed by gas chromatography at defined time intervals. Parallely, cell viability, morphology, apoptosis, cPLA2 and caspase activations were checked. Interestingly, under 150 mu M supplementation the incorporation of palmitic acid was accompanied by the specific release of arachidonic acid. This event was timely correlated with cPLA2 and caspases activations, and the time window of 60 minutes was envisaged for crucial membrane lipidome changes. The simultaneous addition of 50 mu M oleic, 50 mu M arachidonic and 150 mu M palmitic acids to the cell cultures influenced membrane changes with suppression of caspase activation and maintenance of cell viability. These results highlight the role of the membrane asset with fatty acid remodeling and suggest the potential of lipid-based strategies for influencing cell response and fate in human diseases, such as neurodegenerative disorders or tumours.

15-deoxy-delta-12,14-prostaglandin-J(2) (15d-PGJ(2)), an arachidonic metabolite and a natural PPAR gamma agonist, is known to induce apoptosis in tumor cells. In this study, we investigated new therapeutic potentials of 15d-PGJ(2) by determining its anticancer effects in wild-type and doxorubicin-resistant ovarian carcinoma cells. Despite high expression of resistance-inducing genes like MDR1, Bcl2 and Bcl-xl, 15d-PGJ(2) strongly induced apoptosis in doxorubicin-resistant (A2780/AD) cells similar to the wild-type (A2780). This was found to be related to caspase-3/7- and NF-kappa B pathways but not to its PPAR gamma agonistic activity. 15d-PGJ(2) also was able to reduce the doxorubicin resistance of A2780/AD cells at low doses as confirmed by the inhibition of gene expression of MDR1 (p-glycoprotein) and SIRT1 (a drug senescence gene). We also investigated effects of 15d-PGJ(2) on cell migration and transformation using a wound-healing assay and morphological analyses, respectively. We found that 15d-PGJ(2) inhibited migration most likely due to NF-kappa B inhibition and induced transformation of the round-shape A2780/AD cells into elongated epithelial cells due to HDAC1 inhibition. Using a 15d-PGJ(2) analog, we found the mechanism of action of these new activities of 15d-PGJ(2) on SIRT1 and HDAC1 gene expressions and enzyme activities. In conclusion, the present study demonstrates that 15d-PGJ(2) has a high therapeutic potential to kill drug-resistant tumor cells and, the newly described inhibitory effects of this cyclo-oxygenase product on SIRT1 and HDAC will provide new opportunities for cancer therapeutics.

Funding: This study was supported by Fundação para a Ciência e Tecnologia (POCTI/CBO/48922/2002), Portugal. Peroxisome proliferator-activated receptor gamma (PPAR gamma) gene is a nuclear receptor that is involved in thyroid tumourigenesis. Recently, our group has shown that follicular carcinomas underexpressing PPAR gamma protein are more prone to develop distant metastases, to invade locally, to present poorly differentiated areas and to persist after surgery. Aneuploidy is also observed in some thyroid tumours, particularly in the more advanced cases. The aim of the present study was to investigate the association of PPAR gamma expression with the degree of differentiation and ploidy status of benign and malignant thyroid neoplasias. DNA cytometric studies, ploidy and S-phase fraction (SPF) determination, and quantitative RT-PCR analysis of molecular markers specific for thyroid follicular cells, namely Tg (thyroglobulin), TSHR (TSH receptor) and NIS (Na+/I- symporter) were compared between thyroid lesions with positive or negative PPAR gamma protein expression. We observed that PPAR gamma-negative tissues expressed lower levels of Tg mRNA [4.66x10(6) a.u. (arbitrary units) +/- 1.49x10(6)], and were more frequently aneuploid (36%), and presented higher SPF (3.1%+/- 0.4) than PPAR gamma-positive samples (Tg mRNA = 2.54x10(7) a.u. +/- 9.72 x 10(6). P=0.0006; aneuploidy=8%, P=0.0031; SPF=2.2%+/- 0.2, P=0.0430). A similar trend was also observed for TSHR and NIS mRNA, although not reaching statistical significance. This study showed that underexpression of PPAR gamma is associated with poor tumour differentiation, aneuploidy and higher cell proliferative activity. Therapies designed to modulate expression of PPAR gamma may have an impact on the growth of thyroid neoplasias. publishersversion published

Conjugated linoleic acid (CLA) exhibits isomer-specific effects on transepithelial calcium (Ca) transport as well as on cell growth in human intestinal-like Caco-2 cells. However, the molecular mechanisms of action are still unclear. Therefore, this study used a transcriptomic approach to help elucidate the molecular mechanisms underlying such isomer-specific effects. Caco-2 cells were treated with 80 µmol/L linoleic acid (control), 80 µmol/L trans-10, cis-12 CLA, or 80 µmol/L cis-9, trans-11 CLA for 12 d. Ca transport was measured radio-isotopically. RNA was isolated from the cells, labeled, and hybridized to the Affymetrix U133 2.0 Plus arrays (n = 3). Data and functional analysis was preformed using Bioconductor. Using a minimum fold-change criterion of 1.6 and a false discovery rate criterion of P-value 0.05, trans-10, cis-12 CLA altered the expression of 918 genes, whereas, cis-9, trans-11 CLA had no effect on gene expression. Gene ontology analysis revealed that trans-10, cis-12 CLA strongly modulated a number of processes inherently related to carcinogenesis, such as cell cycle, cell proliferation, and DNA metabolism. Trans-10, cis-12 CLA, but not cis-9, trans-11 CLA, increased transepithelial Ca transport in Caco-2 cells, which corresponded to changes in molecular mediators of paracellular (including claudin 2 and 4) and transcellular (calbindin D9k and vitamin D receptor) Ca transport. This microarray-based study highlighted a number of gene expression patterns of relevance to 2 important intestinal processes (carcinogenesis and Ca transport), which were modulated by trans-10, cis-12 CLA. These may help our mechanistic understanding of the role of CLA in promoting gut function and health.

A library of 42 natural and synthetic flavonoids has been screened for their effect on cell proliferation and apoptosis in a human colonic cell line (HT-29). Examples of different classes of flavonoids have been screened, and the effects of hydroxylation, methoxylation and/or C-alkylation at various positions in the A- and B-rings have been assessed. Flavones and flavonols possess greater antiproliferative activity than chalcones and flavanones. With respect to structural modification of flavonoids, C-isoprenylation was by far the most effective, with substitution at the 8-position and longer chains, such as geranyl giving the best results. Finally, most compounds that significantly reduced cell survival also increased caspase activity, suggesting that at least part of their antiproliferative activity might be attributable to an apoptotic response.