Studies On Suppression Of Growth, Induction Of Apoptosis And Inhibition Of Metastasis Of PC-3 Cells By Oridonin

Background:In China,the incidence of prostate cancer has been increasing in recent years.Hormone therapy has been the mainstay of the therapeutic options for metastatic diseases for many years.But many metastatic tumors progress at a median of 18 to 24 months and become hormonal refractory prostate cancer(HRPC).The frequent acquisition of drug-resistant phenotypes and the occurrence of second malignancies often associated with chemotherapy remain serious problems.New therapeutic strategies must be evaluated to improve survival.Oridonin is a naturally active substance isolated from Rabdosia rubescens.The medicinal value of oridonin has been well recognized due to its anti-inflammation and anti-DNA-damaging effects.In recent years,many studies have shown that oridonin possesses anti-proliferative and apoptotic activities against various cancer cells with little toxicity.In our study,we observe whether Oridonin suppresses proliferation,induces apoptosis and inhibits metastasis of PC-3 cells and to explore its possible mechanisms. Partâ… Proliferation-inhibiting effect of Oridonin on PC-3 cellsObjective:To determine proliferation-inhibiting capability of Oridonin on PC-3 cells.Methods:PC-3 cells were treated with different concentrations of Oridonin,then cell viability was analyzed with trypan blue exclusion test,MTT assay and drug concentration-time survival curve test;Cell cycle was tested by flow cytometry.Results:(1) Oridonin effectively inhibited the proliferation of PC-3 cells in a concentration-time dependent way,and the IC50 of PC-3 cells was 10.29μmol/L.(2) Oridonin increased the percentage of G0/G1 phase and decreased S phase of PC-3 cells.Conclusion:Oridonin can inhibit proliferation of PC-3 cells effectively with a concentration-time dependent manner. Partâ…¡Apoptosis-inducing effect of Oridonin on PC-3 cellsObjective:To ensure whether Oridonin can induce the apoptosis of PC-3 cells.Methods:After PC-3 cells were incubated with different concentrations of Oridonin,(1) morphologic character of apoptosis was evaluated by Hochest33258 staining;(2) the percentage of earlier apoptosis cell was analyzed by flow cytometry;(3) the molecular character of apoptosis was analyzed by Western blot detecting Caspase-3 expression.Results:(1) Hochest33258 staining and flow cytometry detection powerfully testify Oridonin can induce the apoptosis of PC-3 cells in a concentration-dependent way;(2) The apoptosis of PC-3 cells,which was induced by Oridonin,kept company with up-regulation and cleavage of Caspase-3.Conclusion:Oridonin can induce the apoptosis of PC-3 cells with a concentration-dependent manner. Partâ…¢Molecular mechanisms of the proliferation-inhibiting and apoptosis-inducing effects of Oridonin on PC-3 cellsObjective:(1) To reveal the relation between the proliferation-inhibiting effect of Oridonin and the change of PC-3 cells cycle;(2) To partly explore the mechanism of apoptosis-inducing effects of Oridonin on PC-3 cells;(3) To determine the important role Caspase-3 plays in the apoptosis of PC-3 cells induced by Oridonin.Methods:(1) The change of cell cycle was analyzed by flow cytometry;(2) The protein expression of COX-2,Survivin,Bcl-2 and Bax in PC-3 cells were detected by Western blot;(3) The protein expression of COX-2,Survivin,CyclinD₂,CyclinE,P27in PC-3 cells were detected by fluorescent quatititive PCR;(4) After the activation of Caspase-3 was inhibited,the changes of proliferation-inhibiting and apoptosis-inducing effects of Oridonin were detected by Z-IETD-fmk blocking tests.Results:(1) Oridonin increased the percentage of G0/G1 phase and decreased S phase of PC-3 cells;(2) Oridonin down-regulated CyclinD₁,Survivin and Bcl-2,and up-regulated P21 and Bax protein in a concentration-dependent way in PC-3 cells;(3) Oridonin down-regulated telomerase activities in a concentration-dependent way in PC-3 cells;(4) The apoptosis-inducing effects of Oridonin were partly suppressed after Z-IETD-fmk blocking the Caspase-3 activation of PC-3 cells.Conclusion:Oridonin inhibits proliferation and induces apoptosis of PC-3 cells through regulating cell cycle protein,blocking "checkpoint" of G1/S phase,down-regulating COX-2,Survivin,CyclinD2,CyclinE and Bcl-2,up-regulated P27and Bax and activating Caspase-3. Partâ…£Metastasis-inhibiting effect of Oridonin on PC-3 cells and its mechanismObjective:To determine metastasis-inhibiting capability of Oridonin on PC-3 cells and to explore its mechanisms.Methods:After PC-3 cells were incubated with different concentrations of Oridonin,(1) the metastasis ability was analyzed with experiment of chemotaxic migration;(2) the mRNA expressions of VEGF, MMP-2 and MMP-9 were analyzed by fluorescent quatititive PCR;(3) the expressions of VEGF,MMP-2 and MMP-9 were analyzed by ELISA.Results:(1) Oridonin effectively inhibited the metastasis of PC-3 cells in a concentration-time dependent way.(2) Oridonin effectively inhibited the expressions of VEGF and MMP-9 in a concentration-time dependent way.Conclusion:Oridonin can inhibit metastasis of PC-3 cells effectively with a concentration dependent manner and the molecular mechanism may relate to Oridonin down-regulating VEGF,MMP-2 and MMP-9 expression.