Correlations of MRP1 gene with serum TGF-β1 and IL-8 in breast cancer patients during chemotherapy

Purpose: To investigate the expressions of multidrug resistance-associated protein I (MRP1) gene, serum transforming growth factor beta-1 (TGF-beta 1) and interleukin-8 (IL-8) in patients with breast cancer during chemotherapy, and to analyze their correlations in chemotherapy. Methods: 346 breast cancer patients admitted to the Department of Surgery (Breast) of Nanjing Drum Tower Hospital from March 2015 to December 2017 were included as study subjects. All selected patients received chemotherapy in our hospital. Quantitative reverse transcription- polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA) were adopted to detect the expression levels of MRP1 mRNA, as well as MRP1, TGF-beta 1 and IL-8 proteins in patients before chemotherapy and at 1, 2, 4 and 8 weeks after chemotherapy. Correlations of MRP1 protein/mRNA with clinical features of patients were analyzed, and Pearson's correlation analysis was performed to examine correlations of MRP1 protein/mRNA with TGF-beta 1 and IL-8 proteins. Results: The expressions of MRP1 mRNA as well as MRP1, TGF-beta 1 and IL-8 proteins were increased with the prolongation of chemotherapy time, and there were statistically significant differences between the two time points (p<0.05). No correlations of MRP1 with the clinical patient features with breast cancer were found. Pearson's correlation analysis showed that the expression level of MRP1 was positively correlated with the expression levels of TGF-beta 1 (r=0.732, p=0.012) and IL-8 (r=0.709, p=0.018), and the expression level of TGF-beta 1 was positively related to that of IL-8 (r=0.714, p=0.015). Conclusion: With the prolongation of chemotherapy time in breast cancer patients, the expression level of MRP1 also increased which may affect the therapeutic effect of chemotherapy in breast cancer patients and lead to drug resistance. TGF-beta 1 and IL-8 may be closely associated with the mechanism of drug resistance in MRP1-guided breast cancer chemotherapy.