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Marijeta Kralj

Publications and source records attributed to Marijeta Kralj.

18 recordsLinked to original sources
PubMed2006

The dicationic derivatives of DBTAA: Interactions with DNA/RNA and antiproliferative effects on human cell lines.

Three dibenzotetraaza[14]annulenes non-covalently interacted with double-stranded DNA and RNA by mixed minor groove and/or intercalative binding mode. Observed interactions were strongly dependent on the steric exposure of positive charges and the length of the linkers of studied compounds as well as on the secondary structure and basepair composition of DNA/RNA. Compound 2 showed pronounced selectivity toward dA-dT-rich sequences and binding mode switch from dominant minor groove binding to ds-DNA to dominant intercalation into ds-RNA. Antiproliferative effect of studied compounds on human tumor and normal cell lines was in good agreement with the strength of observed interactions with DNA/RNA.

Antineoplastic Agents↗
PubMed2006

The novel C-5 aryl, alkenyl, and alkynyl substituted uracil derivatives of L-ascorbic acid: synthesis, cytostatic, and antiviral activity evaluations.

The novel C-5 substituted uracil derivatives of l-ascorbic acid were synthesized by coupling of 5-iodouracil-4,5-didehydro-5,6-dideoxy-l-ascorbic acid with unsaturated stannanes under Stille reaction conditions. The new compounds were evaluated for their antitumoral and antiviral activities. Among all compounds evaluated the 5-propynyl substituted uracil derivative of l-ascorbic acid (7) exhibited the most pronounced cytostatic activities against all examined tumor cell lines (IC(50): 0.2-0.78 microM). However, this compound was also cytotoxic to human normal fibroblasts WI 38. The 5-(phenylethynyl)uracil-2,3-di-O-benzylated l-ascorbic acid derivative (4) exhibited an albeit slight (IC(50): 55-108 microM), but selective inhibitory effect toward all tumor cell lines except for cervical carcinoma (HeLa), pancreatic carcinoma (MiaPaCa-2), laryngeal carcinoma (Hep-2), and colon carcinoma (SW 620), and no cytotoxicity to normal human fibroblast (WI 38). Compound 7 showed some, not highly specific, inhibitory potential against vesicular stomatitis virus, Coxsackie B4 virus, and Sindbis viruses (EC(50): 1.6 microM).

Animals↗
PubMed2006

Synthesis, X-ray crystal structural study, antiviral and cytostatic evaluations of the novel unsaturated acyclic and epoxide nucleoside analogues.

A series of the novel purine and pyrimidine nucleoside analogues were synthesised in which the sugar moiety was replaced by the 4-amino-2-butenyl (2-6 and 10-18) and oxiranyl (8 and 20) spacer. The Z- (2-6) and E-isomers (10-18) of unsaturated acyclic nucleoside analogues were synthesized by condensation of 2- and 6-substituted purine and 5-substituted uracil bases with Z- (1) or E-phthalimide (9) precursors. The oxiranyl nucleoside analogues (8 and 20) were obtained by epoxidation of 1 and 9 with m-chloroperoxybenzoic acid and subsequent coupling with adenine. The new compounds were evaluated for their antiviral and antitumor cell activities. Among the olefinic nucleoside analogues, Z-isomer of adenine containing 4-amino-2-butenyl side chain (6) exhibited the best cytostatic activities, particularly against colon carcinoma (SW 620, IC50 = 26 microM). Its E-isomer 15 did not show any antiproliferative activity against malignant tumor cell lines, except for a slight inhibition of colon carcinoma (SW 620, IC50 = 56.5 microM) cells. In general, Z-isomers showed better cytostatic activities than the corresponding E-isomers. (Z)-4-Amino-2-butenyl-adenine nucleoside analogue 6 showed albeit modest but selective activity against HIV-1 (EC50 = 4.83 microg mL(-1)).

Antineoplastic Agents↗
PubMed2006

Synthesis, photochemical synthesis, DNA binding and antitumor evaluation of novel cyano- and amidino-substituted derivatives of naphtho-furans, naphtho-thiophenes, thieno-benzofurans, benzo-dithiophenes and their acyclic precursors.

As a part of the research on the improvement of an alternative to conventional photodynamic therapy by light-induced formation of intercalators, we synthesized a series of novel heterocyclic compounds and their acyclic precursors. We now report details about their synthesis/characterization in respect to their potential of photoinduced cyclization, interactions with DNA and inhibition of the tumor cell growth in vitro. Among studied compounds only amidino-furyl-substituted phenyl acrylates were efficiently converted to the corresponding naphthofuranes, while their thiophene analogues, all non-charged derivatives and amidino-phenyl-substituted analogues didn't show acceptable photoconversion. The significantly stronger antiproliferative activity of cyclic analogues could be correlated to the property of these molecules to intercalate into DNA. The acyclic molecules did not show any interaction with DNA, correlating with the inferior biological activity, except for one cyano-bearing molecule.

Antineoplastic Agents↗
PubMed2006

Synthesis, structural studies, and cytostatic evaluation of 5,6-di-O-modified L-ascorbic acid derivatives.

The 5,6-di-O-tosylated derivative of l-ascorbic acid was synthesized by selective protection and deprotection of 2,3- and 5,6-dihydroxy functional groups involving 5,6-ditosylation in the final step, while the novel 6-acetoxy, 6-hydroxy, and 6-chloro derivatives of 4,5-didehydro-l-ascorbic acid were obtained by reaction of ditosylated compound with nucleophilic reagents. The analysis of 3JH-4-H-5 homonuclear coupling constants shows that all l-ascorbic acid derivatives except for epoxy and 4,5-didehydro compounds exist in high population as gauche conformers across C-4-C-5 bonds, while 3JC-3-H-5 heteronuclear coupling constants in 4,5-didehydro derivatives indicate cis geometry along C-4-C-5 double bond. The X-ray crystal structure analysis of 2,3-di-O-benzyl-5,6-epoxy- and 5,6-isopropylidene-l-ascorbic acid shows that the oxygen atoms attached at positions 2 and 3 of the lactone ring are disposed in a synperiplanar fashion. Besides that, the dioxolane ring adopts half-chair conformation. The molecules of epoxy derivative are joined into infinite chains by one weak hydrogen bond of C-H...O type. Two O-H...O, and C-H...O hydrogen bonds link the molecules of 5,6-di-O-isopropylidene compound into two-dimensional network. 6-Chloro derivative of 2,3-di-O-benzyl-l-ascorbic acid showed the best cytostatic effects against all tested malignant tumor cells (IC50: approximately 18 microM).

Antineoplastic Agents↗
PubMed2006

Novel cyano- and amidino-substituted derivatives of thieno[2,3-b]- and thieno[3,2-b]thiophene-2-carboxanilides and thieno[3',2':4,5]thieno- and thieno[2',3':4,5]thieno [2,3-c]quinolones: synthesis, photochemical synthesis, DNA binding, and antitumor evaluation.

A series of cyano- and amidino-substituted derivatives of thieno[2,3-b]- and thieno[3,2-b]thiophene-2-carboxanilides and their 'cyclic' derivatives (quinolones) were synthesized. 'Cyclic' compounds displayed a rather strong and differential antiproliferative effect on various cell lines, while the 'acyclic' amidino-substituted compounds were much more active, but showing mostly non-differential cytotoxicity, whereas cyano-substituted compounds (2a,b) produced a strikingly strong effect selectively on HeLa and Hep-2 cell lines. Antiproliferative activity of 'cyclic' derivatives is very likely caused by intercalation into DNA, while their 'acyclic' analogues use other target(s) and/or mechanisms of action.

Amidines↗
PubMed2005

A novel bis-phenanthridine triamine with pH controlled binding to nucleotides and nucleic acids.

The new bis-phenanthridine triamine is characterised by three pK(a) values: 3.65; 6.0 and >7.5. A significant difference in the protonation state of at pH = 5 (four positive charges) and at pH = 7 (less than two positive charges) accounts for the strong dependence of -nucleotide binding constants on nucleotide charge under acidic conditions, whereas at neutral pH all -nucleotide complexes are of comparable stability. All experimental data point at intercalation as the dominant binding mode of to polynucleotides. However, there is no indication of bis-intercalation of the two phenanthridine subunits in binding to double stranded polynucleotides, the respective complexes being most likely mono-intercalative. Thermal stabilisation of calf thymus DNA (ct-DNA) and poly A-poly U duplexes upon addition of is significantly higher at pH = 5 than at neutral conditions. This is not the case with poly dA-poly dT, indicating that the specific secondary structure of the latter, most likely the shape of the minor groove, plays a key role in complex stability. At pH = 5 acts as a fluorimetric probe for poly G (emission quenching) as opposed to other ss-polynucleotides (emission increase), while at neutral conditions this specificity is lost. One order of magnitude higher cytotoxicity of compared to its "monomer" can be accounted for by cooperative action of two phenanthridinium units and the charged triamine linker. The results presented here are of interest to the development of e.g. sequence-selective cytostatic drugs, and in particular for the possibility to control the drug activity properties over binding to DNA and/or RNA by variation of the pH of its surrounding.

Amination↗
PubMed2005

Effect of indomethacin on E-cadherin and beta-catenin expression in HT-29 colon cancer cells.

Nonsteroidal anti-inflammatory drugs (NSAIDs) lower the incidence of and mortality from colon cancer. Although there is much evidence from epidemiological and laboratory studies that NSAIDs have antitumor activity and reduce the incidence of colon cancer, the mechanism of action remains unknown. In this paper, we present the effect of indomethacin on growth inhibition, induction of apoptosis, and alterations in the expression of several genes involved in Wnt signaling in HT-29 colon cancer cells. We have shown that indomethacin reduces the proliferation rate of HT-29 colon cancer cells and induces apoptosis. Concentrations of indomethacin from 10(-4) to 10(-3) M strongly inhibited the growth of HT-29 cells. The inhibition of growth, as well as induction of apoptosis was dose and time dependent. The treatment of cells with 4 x 10(-4) M indomethacin caused strong inhibition of cell growth (about 70%), enhanced expression of APC, decreased expression of beta-catenin and induced expression of E-cadherin proteins. Expression of beta-catenin was not markedly reduced instead, beta-catenin was translocated from the nucleus and cytoplasm to the plasma membrane. These results were confirmed by real-time RT-PCR analysis on mRNA level. At a concentration of 4 x 10(-4) M indomethacin there was increased expression of APC gene (10.9-fold induction; DeltaDeltaCt = 3.43) and E-cadherin gene (3.5-fold induction; DeltaDeltaCt = 1.79). These results suggest the antiproliferative effect of indomethacin may contribute to enhanced cell adhesion through increased expression of E-cadherin and translocation of beta-catenin from the nucleus to the cell membrane.

Active Transport, Cell Nucleus↗
PubMed2005

Novel cyano- and N-isopropylamidino-substituted derivatives of benzo[b]thiophene-2-carboxanilides and benzo[b]thieno[2,3-c]quinolones: synthesis, photochemical synthesis, crystal structure determination, and antitumor evaluation. 2.

Derivatives of 3-chlorobenzo[b]thiophene-2-carboxanilides and their "cyclic" analogues benzo[b]thieno[2,3-c]quinolones were synthesized. Spectroscopic study of the interactions of some representatives of "cyclic" derivatives and their "acyclic" precursors with ds-DNA/RNA supported strong intercalative binding of the former and weak nonintercalative binding of the latter group of compounds. All tested compounds showed a certain antiproliferative effect on a series of human tumor cells and on a normal cell line. Among the compounds, those with one amidino-substituent have shown the best effect. The most active benzo[b]thieno[2,3-c]quinolones induced apparent S and G2/M arrests of the cell cycle, which resulted in apoptosis. These results strongly suggest that the compounds may act as topoisimerase "poisons", which is in good agreement with their intercalative mode of binding to ds-DNA/RNA, in contrast to the studied "acyclic"group of derivatives. 6a and 6d showed the best selectivity by inhibiting the growth of tumor cells but not of normal fibroblasts.

Amidines↗
PubMed2005

Photoinduced switch of a DNA/RNA inactive molecule into a classical intercalator.

Spectroscopic titrations and thermal denaturation experiments show that "acyclic" analogue 1 does not bind to ds-DNA, but under same conditions "cyclic" 2 strongly interacts with ds-DNA and ds-RNA by intercalation into the double helix. Besides, 2 is significantly more effective in inhibition of the tumor cell growth in vitro than 1. We have shown that it is possible to efficiently and irreversibly convert "DNA inactive" compound 1 into "DNA active" compound 2 by light irradiation of the aqueous solutions of the former. This strategy offers a new and attractive approach to photoinduced anticancer therapy.

Cyclization↗
PubMed2005

The novel L- and D-amino acid derivatives of hydroxyurea and hydantoins: synthesis, X-ray crystal structure study, and cytostatic and antiviral activity evaluations.

The novel L- and D-amino acid derivatives of hydroxyurea 5a-o were prepared by aminolysis of N-(1-benzotriazolecarbonyl)amino acid amides 4a-o with hydroxylamine. The hydantoin derivatives 6a-e,m,p were synthesized by base-catalyzed cyclization of amides 4, common precursors for 5 and 6. X-ray crystal structure analysis shows that the C5 atom in 6e possesses the S configuration, which is consistent with the configuration of the starting reagent, l-leucine. Among L-amino acid derivatives of hydroxyurea, 5h and 5i inhibited specifically murine leukemia and human T-lymphocytes (IC(50) = 10-19 microM) and showed selectivity with respect to normal human fibroblasts (WI 38). d-Amino acid derivatives of hydroxyurea 5m and 5o inhibited the growth of all tumor cell lines (IC(50) = 4.8-83.9 microM), but not the growth of normal fibroblasts (WI 38; IC(50) > 100 microM). Results on antiviral evaluations showed that N-(1-benzotriazolecarbonyl)amino acid amide 4m and hydantoin 6m had marked activity against the Davis strain of CMV (4m, EC(50) = 3.2 microg/mL; 6m, EC(50) = 4.0 microg/mL). However, these compounds showed also rather expressed cytotoxicity (4m, CC(50) = 43.4 microg/mL; 6m, CC(50) = 12.5 microg/mL(-1)).

Amino Acids↗
PubMed2005

The novel pyrimidine and purine derivatives of l-ascorbic acid: synthesis, one- and two-dimensional 1H and 13C NMR study, cytostatic and antiviral evaluation.

The syntheses of the novel C-5 substituted pyrimidine derivatives of l-ascorbic acid containing free hydroxy groups at C-2' (6-10) or C-2' and C-3' (11-15) positions of the lactone ring are described. Debenzylation of the 6-chloro- and 6-(N-pyrrolyl)purine derivatives of 2,3-O,O-dibenzyl-l-ascorbic acid (16 and 17) gave the new compounds containing hydroxy groups at C-2' (18) and C-2' and C-3' (19 and 20). Z- and E-configuration of the C4'C5' double bond and position of the lactone ring of the compounds 6-9 were deduced from their one- and two-dimensional (1)H and (13)C NMR spectra and connectivities in NOESY and HMBC spectra. Compounds 15 and 18 showed the best inhibitory activities of all evaluated compounds in the series. The compound 15 containing 5-(trifluoromethyl)uracil showed marked inhibitory activity against all human malignant cell lines (IC(50): 5.6-12.8 microM) except on human T-lymphocytes. Besides, this compound influenced the cell cycle by increasing the cell population in G2/M phase and induced apoptosis in SW 620 and MiaPaCa-2 cells. The compound 18 containing 6-chloropurine ring expressed the most pronounced inhibitory activities against HeLa (IC(50): 6.8 microM) and MiaPaCa-2 cells (IC(50): 6.5 microM). The compound 20 with 6-(N-pyrrolyl)purine moiety showed the best differential inhibitory effect against MCF-7 cells (IC(50): 35.9 microM).

Antineoplastic Agents↗
PubMed2005

Antiviral and cytostatic evaluation of the novel 6-acyclic chain substituted thymine derivatives.

A series of the novel 5-methyl pyrimidine derivatives with an acyclic side chain at the C-6 position were synthesized using lithiation of a 2,4-dimethoxy-5,6-dimethyl pyrimidine and subsequent nucleophilic addition or substitution reactions of the organolithium intermediate thus obtained with acetaldehyde, epichlorhydrine, fluorinated ketones and fluorinated ester. The novel compounds were evaluated for their cytostatic and antiviral activities. Among all the compounds evaluated, two fluorinated acyclic pyrimidine derivatives showed the highest cytostatic activities. The compound containing a 2-hydroxy-3,3,3-trifluoro-1-propenyl side chain exhibited a pronounced effect against breast carcinoma (MCF-7, IC50=8.38 micorg/ml), while the compound with a 2-fluoromethyl-2-acetoxypropyl chain exhibited moderate effect against cervical carcinoma (HeLa, IC50=19.73 microg/ml).

Antineoplastic Agents↗
PubMed2005

Global approach to perinatal medicine: functional genomics and proteomics.

Functional genomics (transcriptomics and proteomics) is a global, systematic and comprehensive approach to the identification and description of the processes and pathways involved in normal and abnormal physiological states. The functional genomics methods most applied today are DNA microarrays and proteomics methods, primarily two-dimensional gel electrophoresis coupled with mass spectrometry. To date, interesting research has been carried out, representing milestones for future implementation of functional genomics/proteomics in perinatal medicine. For instance, possible biomarkers of pre-eclampsia, preterm labor and gestational trophoblastic diseases have been discovered. Further systematic examination of differentially regulated genes and proteins in maternal and fetal tissues and fluids will be required. However, high-throughput technologies reflect biological fluctuations and methodological errors. Large amounts of such different data challenge the performance and capacity of the statistical tools and software available at present. Further major developments in this field are pending and the intellectual investment will certainly result in clinical advances.

Female↗
PubMed2003

p21WAF1/CIP1 is more effective than p53 in growth suppression of mouse renal carcinoma cell line Renca in vitro and in vivo.

PURPOSE: Although there are many controversial reports about the effect of p53 and p21(WAF1/CIP1) overexpression in different human tumor cells, the p53 gene is shown to be a more effective candidate for cancer gene therapy because of its more pronounced ability to induce apoptosis. In the present study, we present the effect of p53 and p21(WAF1/CIP1) overexpression on mouse renal carcinoma cells in vitro and in vivo. METHODS: p53 and p21(WAF1/CIP1) genes were introduced into Renca cells using adenoviral vectors (Ad5CMV-p53 and Ad5CMV-p21). The induction of apoptosis was measured using Annexin V assay and DNA fragmentation analysis. The expression of proteins was examined using immunocytochemistry and Western blot methods. The ability of adenoviral vectors to inhibit tumorigenicity of Renca cells, as well as the growth of pre-established tumors was measured. RESULTS: In vitro growth assays revealed higher growth suppression after Ad5CMV-p21 infection. Although both vectors induced apoptosis, Ad5CMV-p53 was slightly more efficient. In vivo studies in Balb/c mice, demonstrated that tumorigenicity was completely suppressed by Ad5CMV-p21. Besides this, Ad5CMV-p21 significantly inhibited the growth of established tumors, while Ad5CMV-p53 did not. CONCLUSIONS: These data suggest that p21(WAF1/CIP1) is a more potent growth suppressor than p53 of mouse tumor cells Renca. The divergent responses of tumor cells to p21(WAF1/CIP1) overexpression could be due to various networks that differ between species.

Adenoviridae↗
PubMed2003

Endogenous p21WAF1/CIP1 status predicts the response of human tumor cells to wild-type p53 and p21WAF1/CIP1 overexpression.

Expression of exogenous wild-type (wt) p53 protein can suppress the growth and/or induce apoptosis in different tumor cells. The effect of exogenous p21(WAF1/CIP1) expression is more controversial: while it can induce apoptosis in some cells, it can protect against p53-mediated apoptosis in others. We used adenoviral vectors to introduce p53 and p21(WAF1/CIP1) genes into human tumor cell lines with different p53 and/or p21(WAF1/CIP1) status. The cell growth inhibition and the induction of apoptosis were measured. Overexpression of wt p53 induced more efficient growth inhibition and apoptosis in SW 620 (mutant p53) and HeLa (inactivated p53 protein) than in MCF-7 (wt p53) and CaCo-2 cell line, which was the most resistant to p53 overexpression despite the p53 mutation. Unlike HeLa and SW 620 cells, the basal p21 protein level was readily detected in CaCo-2 and MCF-7 cells. Overexpression of p21(WAF1/CIP1) gene induced somewhat less pronounced growth inhibition of all cell lines tested, but it also induced apoptosis in HeLa and SW 620 cells. These results suggest that the basal, but not the inducible, levels of p21(WAF1/CIP1) protein in tumor cells could protect from p53-mediated apoptosis. On the other hand, overexpression of p21(WAF1/CIP1) gene itself can induce apoptosis in cells with no basal p21(WAF1/CIP1) protein level. Possible mechanisms of the differential response to these genes are discussed.

Adenoviridae↗
PubMedDate not supplied

Anticancer and antioxidative effects of micronized zeolite clinoptilolite.

BACKGROUND: Treatment of cancer-bearing mice and dogs with micronized zeolite clinoptilolite (MZ) led to improvement of the overall health status, prolongation of life span and decrease of tumor size in some cases. It also reduced lipid peroxidation in the liver of mice. MATERIALS AND METHODS: The experiments were performed on various tumor cell cultures and tumor-bearing animals. Immunohistochemistry was used to analyze if MZ could interfere with Doxorubicin-induced lipid peroxidation and consequential production of 4-hydroxynonenal (HNE). RESULTS: MZ reduced the metabolic rate of cancer cells and increased binding of HNE to albumin in vitro. It selectively reduced generation of HNE in vivo in tumor stroma after Doxorubicin treatment leaving onset of lipid peroxidation intact in malignant cells. Combined treatment with Doxorubicin and MZ resulted in strong reduction of the pulmonary metastasis count increasing anticancer effects of Doxorubicin. CONCLUSION: Interference of MZ with lipid peroxidation might explain some of the beneficial effects of this particular zeolite in combined cancer therapy.

Adenocarcinoma↗