Screening For Alkaloid Compounds And The Mechanism Of Reversing MDR In Gastric Cancer Cells

Objective:Chemotherapy is the primary treatment for gastric cancer, but one clinically significantly problem that often causes failure of chemotherapy the important cause of chemotherapy failure is multidrug resistance (MDR). Chinese traditional drug possesses the good quality of high performance, multi-target and little toxic action, so it has the value of being investigated. The study was to screen out the compound from five alkaloid compounds which could more efficient to inhibit human gastric cancer cell line SGC7901/VCR; And to research the compound reversed effect in gastric cancer cells and possible mechanism of reversaling MDR on SGC7901/VCR cells. Method:(1) Inhibition of Harmine (HM), Harmaline (HMI), Peimine (PM), Peiminine (PMI) and Oxymatrine (OMT) on SGC7901and SGC7901/VCR cells, and the reverse effect were assayed by MTT assays.(2) Flow cytometry was used to determine intracellular Adriamycin (ADR) concentration and the drug-induced apoptosis rate.(3) Western Blotting was used to examine the resistance protein of P-gp and apoptotic protein of Bcl-2, Bax, Caspase-3, Cleaved caspase-3.(4) Cleaved caspase-3in SGC7901/VCR cells were analyzed by Immunofluorescence. Results:(1) HM, HMI, PM, PMI and OMT could inhibit SGC7901and SGC7901/VCR cells growth. Under the no obvious cell toxicity concentration, PMI could improve the sensitivity of vincristine (VCR), adriamycin (ADR),5-fluorouracil (5-Fu), cisplatin (CDDP).(2) PMI could significantly increase intracellular ADR concentration and reduce the expression of P-gp, by increasing the intracellular drug concentration, reducing drug efflux.(3) PMI compared with5-Fu could induce the resistant cells apoptosis.①Flow cytometry results showed that:The percentage of apoptosis of5-Fu in SGC7901/VCR cells was increased from12.4%individually to17.8%,29.5%and44.5%in combination with PMI, respectively.②The Western blotting results indicated that: The expression of Bcl-2and Bax protein was no difference in experimental and control group. In contrast, an increased expression of Caspase-3and Cleaved caspase-3were observed after the administration of PMI in SGC7901/VCR.③Immunofluorescence assay proved that PMI combination with5-Fu could induce resistant cells apoptosis and inducing resistant cells apoptosis by the way of the expression of Cleaved caspase-3. Conclusions:Peiminine seems to be a promising anti-MDR tumor agent. The mechanism of the element is to restrain the P-gp expression and effect cell apoptosis and so on.