Dr. Gabriella Spengler

Email: spengler.gabriella@med.u-szeged.hu

Phone: +36-62-34-28-43

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Research areas:

  • > Reversal of efflux pump mediated resistance in multidrug resistant bacteria using efflux pump inhibitors (EPIs)

    The phenomenon of multidrug resistance (MDR) is due to the widespread use of antibiotics and biocides, furthermore MDR is responsible for the selection of resistant bacterial strains. The overexpression of multidrug efflux pumps is one of the most important resistance mechanisms in bacteria, because these proteins expel a broad range of antibiotics owing to their poly-substrate specificity. The main goal of using efflux pump inhibitors (EPI) is the improvement of the efficacy of antibiotics. We focus on the screening of EPIs in order to modulate the activity of bacterial MDR efflux pumps, in addition the lead compounds could be applied in combined antimicrobial chemotherapy in order to reverse antibiotic resistance and overcome MDR bacterial infections.


  • > Reversal of multidrug resistance in tumor cells using natural and synthetic compounds

    The reason of unsuccessful chemotherapy can be related to multidrug resistance (MDR) of tumor cells. Our research group focus on two important resistance mechanisms using in vitro tumor models: the resistance mediated by membrane-bound efflux pumps such as P-glycoprotein (ABCB1) and the apoptosis resistance. Nowadays one of the biggest challenges of anticancer chemotherapy is to find new, effective drugs to reverse multidrug resistance and provide new therapeutic approaches.

Selected publications:


  1. Takács D, Csonka Á, Horváth Á, Windt T, Gajdács M, Riedl Z, Hajós G, Amaral L, Molnár J, Spengler G:
    Reversal of ABCB1-related multidrug resistance of colonic adenocarcinoma cells by phenothiazines. Anticancer Res. 2015 Jun;35(6):3245-51.

  2. Matos AM, Reis M, Duarte N, Spengler G, Molnár J, Ferreira MJ:
    Epoxylathyrol derivatives: modulation of ABCB1-mediated multidrug resistance in human colon adenocarcinoma and mouse T-lymphoma cells. J Nat Prod. 2015 Sep 25;78(9):2215-28.

  3. Spengler G, Takács D, Horváth A, Szabó AM, Riedl Z, Hajós G, Molnár J, Burián K:
    Efflux pump inhibiting properties of racemic phenothiazine derivatives and their enantiomers on the bacterial AcrAB-TolC system. In Vivo. 2014 Nov-Dec;28(6):1071-5.

  4. Spengler G, Takács D, Horváth A, Riedl Z, Hajós G, Amaral L, Molnár J:
    Multidrug resistance reversing activity of newly developed phenothiazines on P-glycoprotein (ABCB1)-related resistance of mouse T-lymphoma cells. Anticancer Res. 2014 Apr;34(4):1737-41.

  5. Amaral L, Martins A, Spengler G, Molnar J:
    Efflux pumps of Gram-negative bacteria: what they do, how they do it, with what and how to deal with them. Front Pharmacol. 2014 Jan 3;4:168.

  6. Spengler G, Molnar J, Viveiros M, Amaral L.:
    Thioridazine induces apoptosis of multidrug-resistant mouse lymphoma cells transfected with the human ABCB1 and inhibits the expression of P-glycoprotein. Anticancer Res. 2011 Dec;31(12):4201-5.

  7. Spengler G, Rodrigues L, Martins A, Martins M, McCusker M, Cerca P, Machado L,Costa SS, Ntokou E, Couto I, Viveiros M, Fanning S, Molnar J, Amaral L:
    Genetic response of Salmonella enterica serotype Enteritidis to thioridazine rendering the organism resistant to the agent. Int J Antimicrob Agents. 2012 Jan;39(1):16-21.

  8. 8. Amaral L, Cerca P, Spengler G, Machado L, Martins A, Couto I, Viveiros M, Fanning S, Pages JM:
    Ethidium bromide efflux by Salmonella: modulation by metabolic energy, pH, ions and phenothiazines. Int J Antimicrob Agents. 2011 Aug;38(2):140-5.

  9. Viveiros M, Rodrigues L, Martins M, Couto I, Spengler G, Martins A, Amaral L:
    Evaluation of efflux activity of bacteria by a semi-automated fluorometric system. Methods Mol Biol. 2010;642:159-72.

  10. Martins A, Iversen C, Rodrigues L, Spengler G, Ramos J, Kern WV, Couto I,Viveiros M, Fanning S, Pages JM, Amaral L:
    An AcrAB-mediated multidrug-resistant phenotype is maintained following restoration of wild-type activities by efflux pump genes and their regulators. Int J Antimicrob Agents. 2009 Dec;34(6):602-4.

  11. Martins A, Spengler G, Rodrigues L, Viveiros M, Ramos J, Martins M, Couto I,Fanning S, Pages JM, Bolla JM, Molnar J, Amaral L:
    pH Modulation of efflux pump activity of multi-drug resistant Escherichia coli: protection during its passage and eventual colonization of the colon. PLoS One. 2009 Aug 17;4(8):e6656.

  12. Spengler G, Viveiros M, Martins M, Rodrigues L, Martins A, Molnar J, Couto I, Amaral L:
    Demonstration of the activity of P-glycoprotein by a semi-automated fluorometric method. Anticancer Res. 2009 Jun;29(6):2173-7.

  13. Martins M, Dastidar SG, Fanning S, Kristiansen JE, Molnar J, Pages JM, Schelz Z, Spengler G, Viveiros M, Amaral L:
    Potential role of non-antibiotics (helper compounds) in the treatment of multidrug-resistant Gram-negative infections: mechanisms for their direct and indirect activities. Int J Antimicrob Agents.2008 Mar;31(3):198-208.

  14. Spengler G, Molnár A, Schelz Z, Amaral L, Sharples D, Molnár J:
    The mechanism of plasmid curing in bacteria. Curr Drug Targets. 2006 Jul;7(7):823-41.