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The aim of the present study was to examine and discuss the association between multidrug resistance 1 gene (MDR1) of gastrointestinal tumors, the expression of P-glycoprotein and resistance to chemotherapeutic drugs. In this study, 126 cases of patients with gastrointestinal tumors admitted to hospital from February 2013 to February 2015 were selected. The expression levels of MDR1 gene were obsreved in the control population and patients before and after treatment by fluoresecent quantitative PCR. The protein expression level of P-glycoprotein was determined using western blotting and enzyme-linked immunosorbent assay. In addition, drug resistance was assessed by ATP-TCA chemosensitivity experiments. The results showed that before treatment, the expression of mRNA in MDR1 of tissues of gastrointestinal tract of the 126 cases was 108-fold larger than that of the gastrointestinal tract of the controls (p<0.05), P-glycoprotein was 87-fold larger than the expression level of the controls (p<0.05). The sensitivity of 126 tumor tissues to different chemotherapeutic drugs was determined, and the results showed that most of the tumor tissues were sensitive to chemotherapeutic drugs, and the sensitivity rate reached 96.4%. Following chemotherapy, the expression of mRNA in MDR1 of tumor tissues and the expression of P-glycoprotein decreased (p<0.05). In conclusion, the MDR1 gene and P-glycoprotein have a positive correlation with the occurrence of gastrointestinal tumors, and a negative correlation between the MDR1 gene and P-glycoprotein with resistance of chemotherapeutic drugs. Therefore, the MDR1 gene and P-glycoprotein can be used as references in the identification and diagnosis of gastrointestinal tumors. [ABSTRACT FROM AUTHOR]

Guan Chang Fu Fang (GCFF) is a natural compound, which is extracted from three medicinal plants, Agrimonia pilosa Ledeb., Patrinia scabiosaefolia and Solanum nigrum L. GCFF has demonstrated clinical efficacy in the treatment of colon cancer. At present, 5-fluorouracil (5-FU) is the primary active chemotherapeutic agent used for treating colon cancer. Using median-effect and apoptosis analyses, fluorescence microscopy and western blotting, the present study analyzed the association between GCFF and 5-FU in the human colon adenocarcinoma LoVo cell line. The effect of GCFF on the expression of chemotherapeutic agent-associated genes was also investigated. The results of the synergistic analysis revealed that GCFF exhibited a significant effect upon 5-FU-associated cytotoxicity within the LoVo cell line. This effect was observed over a broad dose-inhibition range (5-95%), but was particularly significant in the lower concentrations. The flow cytometry results revealed that low doses of GCFF or 5-FU induced S -phase arrest, as did a low-dose combination of the two drugs. After 48 h, GCFF significantly suppressed the expression levels of the chemotherapeutic agent resistance-associated genes within the colon cancer cells. The western blot analysis revealed that the combined effects of 5-FU and GCFF were due to a regulation of the B-cell lymphoma-2 family of proteins. The findings of the present study suggested that GCFF, when combined with 5-FU, has the potential to be a novel, chemotherapeutic compound for the treatment of colon cancer. [ABSTRACT FROM AUTHOR]