Mirela Baus Lončar

Chemical composition of the ethanolic propolis extracts and its effect on HeLa cells.

ETHNOPHARMACOLOGICAL RELEVANCE Propolis is a resinous hive product collected by honeybees from various plant sources. It is widely used in traditional medicine and is reported to have a broad spectrum of pharmacological effects (antibacterial, antihepatoxic, antioxidative, anti-inflammatory, etc.). Thus the aim of this study was to assess cytotoxic effect of various ethanol propolis extractions on the cervical tumor cell line (HeLa) and compare it with their phenolic acids and flavonoids composition. MATERIALS AND METHODS Twenty samples of raw propolis were collected from 17 localities of Croatia (I-XVII), 2 of Bosnia and Hercegovina (XVIII, XIX) and 1 of Macedonia (XX). Reverse phase HPLC was used to determine the chemical composition of polyphenols. Biological experiments were carried out in vitro on cervix adenocarcinoma cell line (HeLa). RESULTS Phenolic acids (ferulic acid, p-coumaric acid, caffeic acid) and flavonoids (tectochrysin, galangin, pinocembrin, pinocembrin-7-methylether, chrysin, apigenin, kaempferol, quercetin) have been determined using HPLC analysis in 20 ethanolic propolis extracts. All samples contain tectochrysin in ranges of 0.1988 mg/g (XVIII) to 1.2004 mg/g (III), while caffeic acid and quercetin have not been found. Flavonoid that is most abundant is galangin in ranges from 0.3706 mg/g (XVII) to 47.4879 mg/g (IX). The samples of propolis numbers I, VI and X applied in the investigated concentration range manifested significant reduction of cell growth. GI(50) value as indicator of cytotoxicity among propolis samples showed that propolis number VII is the most effective (GI(50) =76 μg/ml) followed by propolis nos. XV, XVIII and I. CONCLUSION Antiproliferative and cytotoxic effect of propolis on the HeLa cells is not correlating with the concentration of particular components but on establishing the possible synergistic antiproliferative activity of individual phenolic acid and flavonoids. Differences in the chemical composition lead to diversity in biological activity of propolis samples.

Synthesis, DNA/RNA affinity and antitumour activity of new aromatic diamidines linked by 3,4-ethylenedioxythiophene.

A series of novel 2,5-bis(amidinophenyl)-3,4-ethylenedioxythiophenes (5-10 and 15) has been synthesized. Compounds 5-10 bind to the DNA minor groove as the dominant binding site and strongly stabilize the double helix of ct-DNA. Surprisingly, the same compounds also thermally stabilize ds-RNA, whereby most of them form stacked dimers along the RNA double helix. The only exception is compound 15 which, due to its structural features, showed no interaction with DNA or RNA. Compounds 5-10 have shown a moderate to strong cytotoxic effect (GI50=1.5-9.0 μM) on a panel of seven tumour cell lines. The diimidazoline derivative 9, due to its highest inhibitory potential on the growth of all tested tumour cell lines, was investigated in more detail by testing its ability to enter into cells and influence the cell cycle. Compound 9 (5 μM) was internalized successfully in cell cytoplasm during a 30-min incubation period, followed by nuclear localization upon 90-min incubation. Significant arrest in HeLa cells in the G2/M phase, shown by cell cycle analysis at an equitoxic (50 μM) concentration, suggests interaction of a studied compound with cellular DNA as the main mode of biological action.

Trefoil factor family peptides TFF1 and TFF3 in the nervous tissues of developing mouse embryo.

Trefoil factor family peptides (TFF1, TFF2, and TFF3) are predominantly found in mucous epithelia of various organs. However, they have also been reported in the nervous tissue, particularly mouse, rat, porcine, and human brain. The aim of this research was to determine the presence of TFF1 and TFF3 in the nervous system of developing mouse embryo. Mouse embryos, at the stages E15 to E17 were isolated, fixed in 4% paraformaldehyde and embedded in paraffin blocks. Sagittal 6µm sections were made, processed for immunohistochemistry, and incubated with anti-TFF1 or anti-TFF3 primary polyclonal rabbit antibodies. Labeled streptavidin-biotin method was used for TFF detection. TFF1 and 3 were found in the cytoplasm of ganglion cell somata, while TFF3 staining was also visible in the cytoplasm of neurons in different areas and nuclei of brain and medulla oblongata. Neurons in the gray matter of spinal cord were also TFF1 and TFF3 positive, and signal for both peptides was found in the choroid plexus. TFF peptides might be involved in the complex processes of nervous system development and differentiation and brain plasticity.

Antineoplastic DNA-Binding Compounds: Intercalating and Minor Groove Binding Drugs

Abstract DNA intercalating and minor groove binding compounds are new weapons in the battle against malignant diseases. These antineoplastic agents target the DNA molecule and interfere with the cell cycle leading to rapidly proliferating cell death. They are mainly derivates of a naturally occurring organic compound derived from a microorganism or plant. Intercalators usually act as topoisomerase I and/or II poisons, while the mechanisms of DNA minor groove binders are a combination of several steps including topoisomerase poisoning. This paper gives an overview of some of the developed DNA intercalating and minor groove binding compounds, as well as an explanation of their chemical structures, origins, and application in chemotherapy. Sažetak Novo oružje u borbi protiv zloćudnih bolesti su spojevi koji se umeću u dvolančanu strukturu deoksiribonukleinskih kiselina (DNA) ili se vezuju na mali utor DNA. Navedene skupine kemoterapeutika primarno ciljaju molekulu DNA te utječu na stanični ciklus što vodi do smrti brzo dijelećih stanica. Uglavnom su derivati organskih spojeva prirodnog podrijetla, izoliranih iz mikroorganizama ili biljaka. DNA umetnuti spojevi uglavnom djeluju kao otrovi enzima topoizomeraza I i/ili II a spojevi koji se vezuju na mali utor DNA imaju kombinirani mehanizam djelovanja pri čemu je jedan od koraka i otrovanje topoizomeraza. U ovom preglednom članku dajemo pregled nekih od spojeva koji se umeću u molekulu DNA ili vezuju na mali utor DNA, a koji se primjenjuju u kemoterapiji, njihova podrijetla i kemijske strukture.

Trefoil factor family protein 3 (TFF3) is present in cartilage during endochondral ossification in the developing mouse fetus

Trefoil factor family protein 3 (TFF3) is found in cartilage affected by osteoarthritis and septic arthritis, whereas no TFF3 presence is observed in healthy cartilage. During endochondral ossification, bone tissue replaces degenerating cartilage. There is no data about the role of TFF3 in this process. Our aim was to study the localization of TFF3 in cartilage during endochondral ossification in the mouse fetus. CD1 mouse fetuses, days 14-17, were isolated, fixed, and paraffin embedded. Fetuses were cut into 6μm sections, and processed for immunohistochemical staining with affinity purified polyclonal rabbit anti-TFF3 antibody. TFF3 was present in cartilage chondrocytes undergoing endochondral ossification, particularly in zone of proliferation, hypertrophy and calcification as well as in zone of cartilage degeneration during the monitored fetal period. Resting cartilage showed no presence of TFF3, while during endochondral ossification TFF3 localization showed an analogous pattern to that reported in cartilage affected by osteoarthritis and septic arthritis. Our data indicate that the role of TFF3 in these pathological conditions is similar to its role in the physiological process of endochondral ossification.

Trefoil Factor 3 Deficiency Affects Liver Lipid Metabolism

Background/Aims: Tff3 protein plays a well recognized role in the protection of gastrointestinal mucosa. The role of Tff3 in the metabolism is a new aspect of its function. Tff3 is one of the most affected liver genes in early diabetes and fatty liver rodent models. The aim of this study was to investigate the effect of Tff3 deficiency on lipid and carbohydrate metabolism and on markers of oxidative stress that accompanies metabolic deregulation. Methods: Specific markers of health status were determined in sera of Tff3 deficient mice, including glucose level, functional glucose and insulin tolerance. Composition of fatty acids (FAs) was determined in liver and blood serum by using gas chromatography. Oxidative stress parameters were determined: lipid peroxidation level via determination of lipid hydroperoxide and thiobarbituric acid reactive substances (TBARS), antioxidative capacity (FRAP) and specific antioxidative enzyme activity. The expression of several genes and proteins related to the metabolism of lipids, carbohydrates and oxidative stress (CAT, GPx1, SOD2, PPARα, PPARγ, PPARδ, HNF4α and SIRT1) was determined. Results: Tff3 deficient mice showed better glucose utilization in the glucose and insulin test. Liver lipid metabolism is affected and increased formation of small lipid vesicles is noticed. Formation of lipid droplets is not accompanied by increased liver oxidative stress, although expression/activity of monitored enzymes is deregulated when compared with wild type mice. Tff3 deficient mice exhibit reduced expression of metabolism relevant SIRT1 and PPARγ genes. Conclusion: Tff3 deficiency affects the profile and accumulation of FAs in the liver, with no obvious oxidative stress increase, although expression/activity of monitored enzymes is changed as well as the level of SIRT1 and PPARγ protein. Considering the strong downregulation of liver Tff3 in diabetic/obese mice, presence in circulation and regulation by food/insulin, Tff3 is an interesting novel candidate in metabolism relevant conditions.

Histomorphometric Parameters of the Growth Plate and Trabecular Bone in Wild-Type and Trefoil Factor Family 3 (Tff3)-Deficient Mice Analyzed by Free and Open-Source Image Processing Software

Trefoil factor family 3 (Tff3) peptide is present during intrauterine endochondral ossification in mice, and its deficiency affects cancellous bone quality in secondary ossification centers of mouse tibiae. The aim of this study was to quantitatively analyze parameters describing the growth plate and primary ossification centers in tibiae of 1-month-old wild-type and Tff3 knock-out mice (n=5 per genotype) by using free and open-source software. Digital photographs of the growth plates and trabecular bone were processed by open-source computer programs GIMP and FIJI. Histomorphometric parameters were calculated using measurements made with FIJI. Tff3 knock-out mice had significantly smaller trabecular number and significantly larger trabecular separation. Trabecular bone volume, trabecular bone surface, and trabecular thickness showed no significant difference between the two groups. Although such histomorphological differences were found in the cancellous bone structure, no significant differences were found in the epiphyseal plate histomorphology. Tff3 peptide probably has an effect on the formation and quality of the cancellous bone in the primary ossification centers, but not through disrupting the epiphyseal plate morphology. This work emphasizes the benefits of using free and open-source programs for morphological studies in life sciences.

Small interfering RNAs: heralding a new era in gene therapy

Last decades have witnessed a tremendous expansion in knowledge and availability of the genome sequence, which was of great importance for advancements in the field of gene therapy. This led to improved strategies based on use of nucleic acids with sequences complementary to specific target genes in treatment of many diseases. Especially, advancements have been achieved in discovery and use of diverse RNA molecules other than messenger RNAs (mRNAs), transfer RNAs (tRNAs), or ribosomal RNAs (rRNAs). Such RNA molecules, known as non-coding RNAs (ncRNAs), serve diverse biological roles some of which are still elusive. Some biological processes known to be regulated by ncRNAs include transcriptional regulation of genes, gene silencing, messenger RNA stability and translation, development, proliferation, haematopoiesis, apoptosis, protein translocation and chromosome replication. Up to now, the use of ncRNAs as a research tool has greatly improved gene therapy approaches for various diseases (Gallaso 2010), but also substantially improved drug discovery and target validation. In this book chapter, a focus on the use of a particular approach, namely RNAi for improved gene silencing for both, therapeutic approaches and identification of new therapeutic targets is discussed.