The Experimental Study Of The Effect Of Periplocin On The Proliferation Of MDA-MB-231 In Vitro And In Vivo

Objective: The JAK/STAT3 signaling pathway plays an important role in the development and progression of human cancers,especially in breast cancer.This study was to analyze the inhibition effect of of periplocin extracted from cortex periplocae (CPP) on proliferation and invasion of human breast cancer cell line MDA-MB-231 and underlying mechanism.Methods:1 The inhibitory effect on cell growth of MDA-MB-231 was measured by MTT assay in 6 treated or untreated groups (0.625, 1.25, 2.5, 5, 10, 20μg/ml periplocin and control) for three different treatment times (24h, 48h and 72h) .2 Wright and Giemse's staining are carried out for observing the inducible apoptosis by periplocin in MDA-MB-231 cells.3 The expression of stat3 and IL-8 were detected by reverse transcription polymerase chain reaction(RT-PCR).4 The ability of invasiveness was investigated by scarification test.5 p-Stat3 espression in MDA-MB-231 cells was analyzed by immunohisto- chemisty after cells wers treated with cpp.6 The amount of IL-6 secreted from MDA-MB-231 cells treated with CPP(2.5μg/ml)for 24h was analyzed by ELISA.7 Antitumor effect and impact on STAT3 signaling pathway of CPP in tumor-bearing nude mice. MDA-MB-231 cells were washed and adjusted to 5×10~6/ml cell density with PBS. Each BALB/C-nu nude mouse was inoculated subcutaneously in the right back with 10~6 (0.2ml) MDA-MB-231 tumor cells to establish animal model of tumor-bearing nude mice. Two groups were divided, each group has ten nude mice. CPP(30mg/kg)0.2ml or PBS was infused through peri-tumor in tumor-bearing mice. Changes of P-STAT3 and STAT3 were detected by Western blot and RT-PCR. Results:1 Periplocin (0.625~20μg/ml) can significantly inhibit the growth of MDA-MB-231 cells in vitro (p<0.05). The growth inhibition is in dose-dependent and time-dependent manner. The greatest inhibit rate is 70.25% observed in the treatment group of MDA-MB-231 cells by 20μg/ml periplocin for 72 hours.2 Wright and Giemsa's staining reveals MDA-MB-231 cells treated by periplocin had proapoptotic morphology.3. The ability of invasiveness was decreased.4 IL-8 secreted from MDA-MB-231 cells was decreasded aftert treatment with CPP(p<0.05).5 Periplocin inhibits the mRNA expression of the genes stat3 and IL-8 in MDA-MB-231 cells treated by 2.5μg/ml periplocin for 6h, 12h, 24h in time-dependent manner, compared with untreated cells (p<0.05).6 IL-8 secreted from MDA-MB-231 cells was decreasded aftert treatment with CPP(p<0.05).7 Compared to control group, the growth speed of CPP group is lower.The average tumor weight of treated group was 1.437±0.398g and control group group was3.458±0.675g.The tumor inhibition rat was58.44%(compared to the control group, p<0.05). Western blot results showed that the p-stat3 was decreased than that in control group(P<0.05). RT-PCR results showed that stat3 was decreased than that in control group(P<0.05).Conclusion:1 Periplocin inhibits significantly proliferation of the human breast cancer MDA-MB-231 cells in vitro in dose-dependent and time-dependent manner.2 The treatment of periplocin induced apoptosis of MDA-MB-231 cells in vitro.3 In the MDA-MB-231 cells, periplocin represses the Stat3 signaling pathway through downregulating the expression of stat3.4 Periplocin could inhibit MDA-MB-231 cell proliferation by interfering with the stat3 signaling pathway., inhibit invasiveness by inhibit IL-8. 5 CPP has significant inhibition effect on breast carcinoma cell lines MDA-MB-231 in vitro and in vivo.