Microarray technology

The normal functions of the cells are based on a strict and regulated expression of various genes. If this precise hierarchy of gene actions becomes unregulated or disturbed due to different genetic or environmental effects, the result will be abnormal cellular function that eventually could lead pathological alterations, including carcinogenic transformation or apoptosis. To understand the complex mechanisms and networks involved in biological processes and diseases, it is not enough to analyze isolated pathways, single gene functions or a single genetic event. A living organism has to be studied as a complex system and all genes involved in different biological processes need to be analyzed simultaneously: a systems biology approach should be applied. In the beginning of the 1990’s years, a new, high throughput technology - called microarray technology – was developed to measure the expression levels of large numbers of genes simultaneously or to genotype multiple regions of a genome. Microarrays have dramatically accelerated many types of investigation since a microarray experiment can accomplish many genetic tests in parallel. This review summarizes some of aspects of the microarray technology, including sample preparations, application possibilities and data analysis

MicroRNA profile of polyunsaturated fatty acid treated glioma cells reveal apoptosis-specific expression changes

<p>Abstract</p> <p>Background</p> <p>Polyunsaturated fatty acids (PUFAs) such as γ-linolenic acid (GLA), arachidonic acid (AA) and docosahexaenoic acid (DHA) have cytotoxic action on glioma cells.</p> <p>Results</p> <p>We evaluated the cytotoxic action of GLA, AA and DHA on glioma cells with specific reference to the expression of miRNAs. Relative expression of miRNAs were assessed by using high throughput nanocapillary real-time PCR. Most of the miRNA target genes that showed altered expression could be classified as apoptotic genes and were up-regulated by PUFA or temozolomide treatment, while similar treatments resulted in repression of the corresponding mRNAs, such as <it>cox2</it>, <it>irs1</it>, <it>irs2</it>, <it>ccnd1</it>, <it>itgb3</it>, <it>bcl2</it>, <it>sirt1</it>, <it>tp53inp1 </it>and <it>k-ras</it>.</p> <p>Conclusions</p> <p><it>Our </it>results highlight involvement of miRNAs in the induction of apoptosis in glioma cells by fatty acids and temozolomide.</p

Lipidomic analysis reveals a radiosensitizing role of gamma-linolenic acid in glioma cells

Previous studies have demonstrated that gamma-linolenic acid (GLA) is effective against glioma cells under both in vitro and in vivo conditions. In the present study we determined how GLA alone or in combination with irradiation alters the fatty acid (FA) and lipid profiles, the lipid droplet (LD) content, the lipid biosynthetic gene expression and the apoptosis of glioma cells. In GLA-treated cells direct correlations were found between the levels of various FAs and the expression of the corresponding FA biosynthetic genes. The total levels of saturated and monosaturated FAs decreased in concert with the down-regulation of FASN and SCD1 gene expression. Similarly, decreased FADS1 gene expression was paralleled by lowered arachidonic acid (20:4 n-6) and eicosapentaenoic acid (20:5 n-3) contents, while the down-regulation of FADS2 expression was accompanied by a diminished docosahexaenoic acid (22:6 n-3) content. Detailed mass spectrometric analyses revealed that individual treatments gave rise to distinct lipidomic fingerprints. Following uptake, GLA was subjected to elongation, resulting in dihomo-gamma-linolenic acid (20:3 n-6, DGLA), which was used for the synthesis of the LD constituent triacylglycerols and cholesteryl esters. Accordingly, an increased number of LDs were observed in response to GLA administration after irradiation. GLA increased the radioresponsiveness of U87 MG cells, as demonstrated by an increase in the number of apoptotic cells determined by FACS analysis. In conclusion, treatment with GLA increased the apoptosis of irradiated glioma cells, and GLA might therefore increase the therapeutic efficacy of irradiation in the treatment of gliomas

Polyunsaturated fatty acids synergize with lipid droplet binding thalidomide analogs to induce oxidative stress in cancer cells

<p>Abstract</p> <p>Background</p> <p>Cytoplasmic lipid-droplets are common inclusions of eukaryotic cells. Lipid-droplet binding thalidomide analogs (2,6-dialkylphenyl-4/5-amino-substituted-5,6,7-trifluorophthalimides) with potent anticancer activities were synthesized.</p> <p>Results</p> <p>Cytotoxicity was detected in different cell lines including melanoma, leukemia, hepatocellular carcinoma, glioblastoma at micromolar concentrations. The synthesized analogs are non-toxic to adult animals up to 1 g/kg but are teratogenic to zebrafish embryos at micromolar concentrations with defects in the developing muscle. Treatment of tumor cells resulted in calcium release from the endoplasmic reticulum (ER), induction of reactive oxygen species (ROS), ER stress and cell death. Antioxidants could partially, while an intracellular calcium chelator almost completely diminish ROS production. Exogenous docosahexaenoic acid or eicosapentaenoic acid induced calcium release and ROS generation, and synergized with the analogs <it>in vitro</it>, while oleic acid had no such an effect. Gene expression analysis confirmed the induction of ER stress-mediated apoptosis pathway components, such as GADD153, ATF3, Luman/CREB3 and the ER-associated degradation-related HERPUD1 genes. Tumor suppressors, P53, LATS2 and ING3 were also up-regulated in various cell lines after drug treatment. Amino-phthalimides down-regulated the expression of CCL2, which is implicated in tumor metastasis and angiogenesis.</p> <p>Conclusions</p> <p>Because of the anticancer, anti-angiogenic action and the wide range of applicability of the immunomodulatory drugs, including thalidomide analogs, lipid droplet-binding members of this family could represent a new class of agents by affecting ER-membrane integrity and perturbations of ER homeostasis.</p

Lipid droplet binding thalidomide analogs activate endoplasmic reticulum stress and suppress hepatocellular carcinoma in a chemically induced transgenic mouse model

BACKGROUND: Hepatocellular carcinoma (HCC) is the most frequent and aggressive primary tumor of the liver and it has limited treatment options. RESULTS: In this study, we report the in vitro and in vivo effects of two novel amino-trifluoro-phtalimide analogs, Ac-915 and Ac-2010. Both compounds bind lipid droplets and endoplasmic reticulum membrane, and interact with several proteins with chaperone functions (HSP60, HSP70, HSP90, and protein disulfide isomerase) as determined by affinity chromatography and resonant waveguide optical biosensor technology. Both compounds inhibited protein disulfide isomerase activity and induced cell death of different HCC cells at sub or low micromolar ranges detected by classical biochemical end-point assay as well as with real-time label-free measurements. Besides cell proliferation inhibiton, analogs also inhibited cell migration even at 250 nM. Relative biodistribution of the analogs was analysed in native tissue sections of different organs after administration of drugs, and by using fluorescent confocal microscopy based on the inherent blue fluorescence of the compounds. The analogs mainly accumulated in the liver. The effects of Ac-915 and Ac-2010 were also demonstrated on the advanced stages of hepatocarcinogenesis in a transgenic mouse model of N-nitrosodiethylamine (DEN)-induced HCC. Significantly less tumor development was found in the livers of the Ac-915- or Ac-2010-treated groups compared with control mice, characterized by less liver tumor incidence, fewer tumors and smaller tumor size. CONCLUSION: These results imply that these amino-trifluoro-phthalimide analogs could serve potent clinical candidates against HCC alone or in combination with dietary polyunsaturated fatty acids

Lipid-membrán iskola a Szegedi Biológiai Központban = Lipid-membrane school at the Biological Research Center

Tisztelegve az elhúnyt Farkas Tibor akadémikus emlékének, a Lipid-Membán Iskola a Szegedi Biológiai Központban minden tekintetben végrehajtotta a pályázatban tervezett feladatait, teljesítette misszióját. Képes volt a meglévő tudás valamint eszközállomány összefogására, koncentrált és hatékony kihasználására. A közös munka eredményeképpen számos, stratégiailag igen jelentős fejlesztés vált lehetővé. Nagy számú új, eredeti tudományos eredmény (köztük több review, ill. könyv) publikációjára került ill. kerül még sor a program lezárását követően. Törekvéseink fénypontját jelzik az egymolekula követésére alkalmas mikroszkópiás laboratórium (nanotechnológiai alapú membrán kutatóhely, SzBK) ill. az első hazai lipidomikai vertikum (SzTE, SzBK ) teljes kiépítése. Kiemelendő, hogy a program célkitűzésének megfelelően a kutatásba számos hallgatót vontunk be. Szakdolgozatok ill. PhD disszertációk születtek a pályázat támogatásával. Aktivitásunk egyértelmű nemzetközi elismeréseképpen 2006-ban Magyarországon kerül megrendezésre a Nemzetközi Lipidtudományi Konferencia (ICBL) kollégáink rendezésében, Vígh László elnökletével. A Lipid-Membrán Iskola szegedi résztvevői az alap- és alkalmazott lipid és membrán kutatási eredményeik, valamint a kiépült együttműködéseik alapján sikeresen részévé váltak a Dél-Alföldi Neurobiológiai Tudásközpontnak. | Saluting to the memory of late Tibor Farkas, the Lipid-Membrane School in the Szeged Biological Research Center successfully accomplished its major goals and fulfilled its mission. The school became capable for bringing together the preexisting knowledges and resources, by effectively concentrate and exploit them. As a result of the common and complementary efforts, several highly important and ambicious projects have been implemented. As a result of these, high number of new, original publications, reviews indicated the success. Amongst of our most remarkable achievements, we should mention the foundation of the nanotech based single molecule microscopy technique, allowing the real-time monitoring of most various lipid-membrane events (BRC). We are also proud, that the first Hungarian lipidomics lab can start soon its operation (SzTE, BRC). Several students participated in our activity: prepared diploma work and PhD thesis. Best highlighting our successful activity, our colleaques will organize the next International Congress of Lipid Sciences (ICBL), chaired by Laszlo Vigh. Based on their basic and applied research related activities and cooperation, most of the participants of the peresently terminated Szeged Lipid-Membrane School have joined successfully the Szeged Neurobiological Knowledge Center