نقش مسیر پیام رسانی Nrf2-ME-1 در ایجاد مقاومت به داروی شیمی درمانی 5- فلوئورویوراسیل در رده سلولی سرطان معده.

Abstract

Background: 5-fluorouracil (5-FU) is one of the first line chemotherapeutics in the treatment of gastric cancer (GC). However, the efficacy of this agent is limited due to development of multidrug resistance (MDR) phenotype. The aim of this study was to investigate the role of nuclear factor erythroid 2-related factor 2 (Nrf2) and key downstream targeting molecule, malic enzyme-1 (ME-1), in the induction of drug resistance. Main methods: First, 5-FU resistant MKN-45 (MKN-45/DR) cell line was generated by employing IC50 concentration of the agent followed by a resting cycles. Cell viability and apoptosis were evaluated by MTT assay, DAPI staining and flow cytometry. mRNA expression levels of Nrf2 and ME-1 were measured by qRT-PCR technique. Morphology analysis and combination index calculation were assessed by Image J and compuSynsoftwares, respectively. Key finding: The value for IC50 in 5-FU resistant cells increased from 8.81 ± 0.209 to 142.4 ± 0.060 µM with a considerable morphological changes from round to elongated shape (P=0.016). Nrf2 and ME-1 expression levels were decreased in resistant cells with a marked increase in MDR1 mRNA level compared to sensitive cells. The cytotoxicity assays, MTT, DAPI and flow cytometry, revealed that the combination of Nrf2 inhibitors, luteolin and brusatol had synergistic effects on 5-FU induced cytotoxicity. Moreover, combined incubation of MKN-45/DR cells with these inhibitors, exponentially increased Nrf2 and ME-1 mRNA levels (P < 0.001). Significance: Our findings suggest that the combined application of both luteolin and brusatol, through their impact on the Nrf2 signaling pathway, can be considered as a novel strategy to overcome 5-FU resistance in GC patients.