Intrinsic Activity, 2018; 6 (Suppl. 1): A4.4
doi:10.25006/IA.6.S1-A4.4
From:
24th Scientific Symposium of the Austrian Pharmacological Society (APHAR)
Graz, 27 – 28 September 2018
MEETING ABSTRACT
Intrinsic Activity,
2018; 6 (Suppl. 1):

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A4.4
12-Oxo-chenodeoxycholic acid potentiates doxorubicin-induced oxidative stress through Nrf2 axis in breast adenocarcinoma cells
Bojan Stanimirov1,*, Karmen Stankov1, Nebojša Pavlović2, Maja Đanić3, Jasmina Katanić1, Iva Barjaktarović4 and Momir Mikov3
  1. Department of Biochemistry, Faculty of Medicine, University of Novi Sad, Vojvodina, Serbia
  2. Department of Pharmacy, Faculty of Medicine, University of Novi Sad, Vojvodina, Serbia
  3. Department of Pharmacology, Faculty of Medicine, University of Novi Sad, Vojvodina, Serbia
  4. Centre of Forensic Medicine, Toxicology and Molecular Genetics, Faculty of Medicine, University of Novi Sad, Vojvodina, Serbia
* Corresponding author: e-mail

Background: As a transcription factor, nuclear factor E2-like factor 2 (Nrf2) controls the expression of genes encoding cytoprotective proteins, including anti­oxidant enzymes counteracting oxidative and electrophilic stress to maintain redox homeostasis. Aberrant activetion of Nrf2 in malignant cells promotes high expression of cyto­protective proteins, which can decrease the efficacy of anti­neoplastic agents used for chemotherapy. The aim of this study was to analyse the expression of NRF2 gene as well as anti­oxidative system genes in a human breast adenocarcinoma cell line (MCF-7) treated with doxorubicin and the bile acid 12-oxo-cheno­deoxy­cholic acid (12-mono­keto­cholic acid, 12MKC).

Methods: The MCF-7 cell line was maintained in required micro-environmental conditions until confluence was reached. Cells were afterwards treated with 0.25 µM of doxorubicin (D group) or co-treated with 0.25 µM doxorubicin and 25 µM 12MKC (DM group). Following 24 h of incubation, cells were collected, RNA was isolated and transcribed into cDNA. The expression of the genes for Nrf2 (NRF2), superoxide dismutase (SOD), catalase (CAT), and β-actin (ACTB) as a housekeeping gene, was determined using RT-qPCR. Gene expression was analysed using comparative 2−ΔΔCT method and statistical analysis was performed using Anova and Tukey’s post-hoc test.

Results: Compared to untreated group of cells, treatment of MCF-7 cells reduced expression of NRF2 both in the D and in the DM group: 2.74 ± 0.57 (p < 0.001) and 1.74 ± 0.59 (p = 0.014), respectively. Expression of SOD was also repressed in the D and in the DM group: 3.68 ± 0.78 (p < 0.001) and 1.11 ± 0.37 (p < 0.001), respectively. On the other hand, the expression of CAT was induced in the D group 1.50 ± 0.34-fold (p > 0.05), whereas supressed in the DM group 1.15 ± 0.39-fold (p > 0.05), compared to control.

Discussion: Oncogene-induced mutations with gain of function of Nrf2 promote both ROS detoxification and tumorigenesis, whereas suppression of Nrf2 in neoplastic cells and alters redox homeostasis of malignant cells. Through suppression of NRF2, SOD and CAT genes, 12MKC exerts potential to impinge cellular anti­oxidative defence at the transcriptional level in MCF-7 cells treated with doxorubicin, with potential favourable effects in terms of therapeutic outcome.

Acknowledgements: Supported by Horizon 2020 MEDLEM (project no. 690876), the Provincial Secretariat for Science and Technological Development, Autonomous Province of Vojvodina (project no. 114-451-2072-/2016-02) and the Ministry of Education, Science and Technological Development, Republic of Serbia (grant III 41012).

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published online:
20 September 2018