Jasna Franekić Čolić

Ruđer Bošković Institute, Zagrabia, Grad Zagreb, Croatia

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Publications (5)9.65 Total impact

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    ABSTRACT: Cited By (since 1996):11, Export Date: 18 October 2014
    No preview · Article · Jan 2009 · Journal of Applied Toxicology
  • kdurgo@yahoo.com · Lidija Vuković · Gordana Rusak · Maja Osmak · Jasna Franekić Čolić
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    ABSTRACT: Flavonoids are phytochemicals exhibiting a wide range of biological activities, among which are antioxidant activity, the ability to modulate activity of several enzymes or cell receptors and possibility to interfere with essential biochemical pathways. Using human laryngeal carcinoma HEp2 cells and their drug-resistant CK2 subline, we examined the effect of five flavonoids, three structurally related flavons (quercetin, fisetin, and myricetin), one flavonol (luteolin) and one glycosilated flavanone (naringin) for: (i) their ability to inhibit mitochondrial dehydrogenases as an indicator of cytotoxic effect, (ii) their influence on glutathione level, (iii) antioxidant/prooxidant effects and influence on cell membrane permeability, and (iv) effect on expression of cytochrome CYP1A1. Cytotoxic action of the investigated flavonoids after 72 hours of treatment follows this order: luteolin>quercetin>fisetin>naringin>myricetin. Our results show that CK2 were more resistant to toxic concentrations of flavonoids as compared to parental cells. Quercetin increased the total GSH level in both cell lines. CK2 cells are less perceptible to lipid peroxidation and damage caused by free radicals. Quercetin showed prooxidant effect in both cell lines, luteolin only in HEp2 cells, whereas other tested flavonoids did not cause lipid peroxidation in the tested cell lines. These data suggest that the same compound, quercetin, can act as a prooxidant, but also, it may prevent damage in cells caused by free radicals, due to the induction of GSH, by forming less harmful complex. Quercetin treatment damaged cell membranes in both cell lines. Fisetin caused higher cell membrane permeability only in HEp2 cells. However, these two compounds did not enhance the damage caused by hydrogen peroxide. Quercetin, naringin, myricetin and fisetin increased the expression of CYP1A1 in both cell lines, while luteolin decreased basal level of CYP1A1 only in HEp2 cells. In conclusion, small differences in chemical structure of flavonoids led to drastic change of their biological effects.
    No preview · Article · Jan 2007
  • Ksenija Durgo · Lidija Vuković · Gordana Rusak · Maja Osmak · Jasna Franekić Čolić

    No preview · Article · Sep 2006 · Toxicology Letters
  • Ksenija Durgo · Sanjica Jakupec · Jasna Franekić Čolić · Maja Osmak

    No preview · Article · Sep 2003 · Toxicology Letters
  • K. Durgo · M. Osmak · V. Garaj-Vrhovac · J.F. Čolić
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    ABSTRACT: Background and Purpose: The major problem in cancer chemotherapy is the ability of tumor cells to develop resistance to anti-cancer drugs. In attempt to overcome drug-resistance, various compounds have been tested. Among them are plant compounds of Brassicaceae family. In the present study we examined the effect of cauliflower's extract and its active compound indole-3-carbinol on the two most important causes of drug-resistance: the activity of P-glycoprotein and the level of intracellular glutathione (GSH). The experiments were done on the human parental laryngeal carcinoma HEp2 cells and its (to cisplatin and vincristine) resistant CK2 subline with increased activity of P-glycoprotein and increased level of GSH. Materials and Methods: Cytotoxicity was determined using a modified colorimetric MTT assay. The effect of the cauliflower's extract and indole-3-carbinol on the activity of P-glycoprotein was determined by their influence on cell sensitivity to vinscristine. Intracellular GSH content was examined by the spectrophotometric procedure developed by Tietze. Results: Results showed that neither cauliflower extract nor indole-3-carbinol altered the sensitivity of HEp2 and CK2 cells to vincristine, suggesting that these compounds may not change the activity of P-glycoprotein. However, both the cauliflower extract and indole-3-carbinol increased the level of GSH in parental HEp2 cells, but reduced its level in drug-resistant CK2 cells. Conclusions: The extract of caulifower and indole-3-carbinol may, by reducing the level of GSH in drug-resistant cells, increase their sensitivity to anticancer drugs and improve the effectiveness of cancer treatment.
    No preview · Article · Dec 2002 · Periodicum Biologorum