| Cancer is a major global diseases to human and the morbidity increasing year by year. Chemotherapy always plays an important role in therapy of cancer. However, multidrug resistance(MDR) of tumor have become the main obstacle in cancer chemotherapy. Therefore, searching low toxic and effective agents against MDR has become a research hotspot. The aim of present study was to investigating the reversal effects of Ganoderma lucidum polysaccharides(GLPS) and choline on SGC7901/ADR cells. Discuss the possible mechanism of reverse, to provide the theoretical basis and experimental evidence for MDR reversal agents.Methods:(1)First, preparation the water-soluble of Ganoderma lucidum. Th&content of Ganoderma lucidum polysaccharides was determined by the method of phenol-sulfuric acid. While the content of choline was measured by spectro-photometry at the wavelength of526nm.(2)MTT assay was used to determie the cytotoxicity of GLPS and choline on SGC7901/ADR cells, calculated the IC20and IC50value of them. Take the inhibition rate≤20%as the none-toxic dose of GLPS and choline, the concentration were used as the experimental concentration in the following experiments, too.(3)MTT method was applied to detect the reversal effect of GLPS and choline on SGC7901/ADR cells, calculated the reversal fold.(4)Flow cytometry(FCM) was applied to detect the intracellular accumulation of Rhodamine-123(Rhol23) or adriamycin(ADR) in SGC7901/ADR cells and calculate the multiples of fluorescence accumulation.(5)RT-PCR was used to determine the influence of GLPS and choline on P-gp expression of SGC7901/ADR cells, which was encoding by MDR1gene.Results:(1)The content of GLPS and choline in the water-soluble of Ganoderma lucidum were12.61%and5.98%, respectively.(2) The IC5o of GLPS and choline were8669.00μg/mL and792.52μg/mL, respectively.The IC20of them were403.23μg/mL and106.71μg/mL, respectively.(3)With the non-toxic dose of GLPS and choline treatment on SGC7901/ADR cells for48h, the IC50of SGC7901/ADR cells were all declined and showed dose-dependent manner in some degree. The reversal fold of GLPS is3.25to5.65, while choline is1.42to3.03.The reversal effect of GLPS is better than choline.(4)Treatment on SGC7901/ADR cells with different concentration of GLPS and choline, the intracellular mean fluorescence intensity of SGC7901/ADR cells were all increased, showed that GLPS and choline all have good reversal effects. The best reversal dose of GLPS and choline were400μg/mL and20μg/mL, respectively.(5)The results of RT-PCR showed that the transcription level of MDR1gene were declined compared with the control group after treatment on SCC7901/ADR cells with GLPS, indicated that GLPS could reverse MDR through down-regulate the expression of MDR1. While the transcription level of MDR1gene weren’t declined compared with the control group after treatment on SGC7901/ADR cells with choline, indicated that the reversal agents of choline is irrelevant to P-gp. Further study should be carried out.Conclusions:Both GLPS and choline have the effect of reversing MDR of tumor. The reversal mechanism of GLPS may be as follows: GLPS can reduce the transcription level of MDR1gene, which lead to decrease the expression of P-gp. Thereby increasing the concentration of anticancer drug in cells. The reversal agents of choline have nothing with P-gp. Since GLPS have low toxicity, and its reversal effect is much better than choline, GLPS maybe an effective ingredients of Ganoderma lucidum water-soluble, which could reverse MDR. GLPS possess enormous value of exploitation and research. |
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