Page 101 - SRPSKO DRUŠTVO ISTRAŽIVAČA RAKA

SDIRSACR Oncology Insights

P02

Inhibition of the membrane transporters in 5-fluorouracil-resistant colorectal cancer cells by chlorogenic
acid

Milena Milutinović, Anđela Andrejić, Milan Stanković, Danijela Nikodijević

University of Kragujevac, Faculty of Science, Department of Biology and Ecology, Kragujevac, Republic of Serbia

Keywords: ABC transporters, resistance, 5-fluorouracil

Background: In the case of colorectal cancer, one of the most common and deadliest cancers, the commonly used
chemotherapeutic agent is 5-fluorouracil (5-FU). However, a problem facing modern medicine is the development of
resistance to chemotherapy in tumor cells. In several studies, chlorogenic acid (CHA), found in green tea and coffee
extracts, has demonstrated a wide range of pharmacological actions, including anticancer effects. In our study, the
potential of CHA to reverse the sensitivity of 5-FU-resistant colorectal cancer cells and inhibit the expression of key
membrane transporters involved in the resistance development was investigated.
Material and Methods: Human colon carcinoma (HCT-116) cell lines, resistant to 5-FU, were used as a model system.
The cytotoxicity of 5-FU and the achieved resistance were determined using an MTT assay and expressed as IC50
values and resistance factors for 24 h and 72 h. Effects of CHA on the expression of different ABC (ATP Binding Cassette)
membrane transporters expressed in colon tissue were determined in HCT-116 5-FU resistant cells by qPCR methods.
Results: Results show that CHA has the potential to inhibit the expression of some transporters on the transcriptional
level in 5-FU resistant HCT-116 cells. The significant result is the reduced relative expression of MRP5 and MRP8
membrane transporters in resistant cells treated with CHA, considering that these transporters were included in
resistance development (their expression was increased in resistant cells compared to parental cells in our results).
Conclusions: According to its inhibitory activity on expression of the key membrane transporters in the emergence of
5-FU resistance in HCT-116 cells, chlorogenic acid should be further investigated for potential use to re-enhance the
sensitivity of resistant cells to chemotherapeutics and inhibit their efflux. The effects on ABC transporter activity and
more detailed experiments still need to be evaluated.

Acknowledgments and funding: This work was supported by the Ministry of Education, Science and Technological
Development of the Republic of Serbia (Agreement no. 451-03-65/2024-03/ 200122).

P03

The impact of silibinin on the expression of genes involved in the process of apoptosis in malignant cells
treated with selective COX-2 inhibitor

Vanesa Sekeruš , Nebojša Pavlović , Vesna Kojić , Bojan Stanimirov , Karmen Stankov 1
1,2
4
3
1
1Department of Biochemistry, Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia
2Institute for Pulmonary Diseases of Vojvodina, Sremska Kamenica, Serbia
3Department of Pharmacy, Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia
4Faculty of Medicine, University of Novi Sad, Novi Sad; Oncology Institute of Vojvodina, Sremska Kamenica, Serbia

Keywords: lung neoplasms; cyclooxygenase 2; celecoxib; silybin; apoptosis; carcinogenesis

Background: Chronic inflammation and increased activity of the enzyme cyclooxygenase-2 (COX-2) are recognized as
important factors in the etiopathogenesis of lung cancer. Celecoxib, a selective COX-2 inhibitor, is being considered as a
potential agent in the prevention and therapy of lung cancer. The aim of this study was the in vitro determination of the
cytotoxic effect of celecoxib and silibinin (silybin), a natural flavonolignan isolated from the plant Silybum marianum,
on the human cell line of lung adenocarcinoma (A549), as well as an analysis of the expression of genes involved in
inflammatory and apoptotic cell responses.
Material and Methods: The cytotoxicity of celecoxib and silibinin on A549 cells was evaluated using dye exclusion
and MTT assays. Quantification of gene expression was performed using the quantitative real-time polymerase chain
reaction with reverse transcription (qRT-PCR), and was analyzed using the comparative ΔΔCt method, with ACTB as a

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