Effects Of Interleukin-2 On Proliferation, Apoptosis And Paracrine Of Prostatic Epithelial Cells

Chapter oneInterleukin-2 and Its Receptors Expression in Prostatic Epithelial CellsObjective:Interleukin-2(IL-2) plays a significant role in benign prostatic hyperplasia(BPH).In the present study,the expression of IL-2 in BPH and its relationship with inflammation was firstly evaluated and then the expression of Interleukin-2 receptors(Rα,Rβ,Rγ) in human prostatic epithelial cell line BPH-1 was investigated.Methods:The expression change of IL-2 protein in BPH specimens with or without inflammatory infiltrates was examined by immunohistochemistry.The expression of Interleukin-2 receptors(Rα, Rβ,Rγ) mRNA and protein in BPH-1 cells were determined by reverse transcription-polymerase chain reaction(RT-PCR) and Western blot.Results:The expression of IL-2 was increased in BPH specimens with inflammatory infiltrates.Both Interleukin-2 receptors(Rα,Rβ,Rγ) mRNA and protein were expressed in BPH-1 cells.Conclusions:IL-2 expression is associated with inflammatory pathology in BPH.Interleukin-2 receptors(Rα,Rβ,Rγ) are expressed in human prostatic epithelial cell line BPH-1.This cell line could be used for the investigation of the actions of IL-2 on prostatic epithelial cells. Chapter twoInterleukin-2 Stimulates Proliferation of Prostatic Epithelial Cells through ERK1/2 Signal PathwayObjective:To investigate the mechanism of IL-2 on the proliferation of human prostatic epithelial cell line BPH-1.Methods:Cell proliferation was assessed by the MTT assay. Western blot was used to determine the status of activaton of ERK1/2, p38 and JNK.Results:IL-2 stimulated proliferation of BPH-1 cells.IL-2 induced activation of ERK1/2,but not activation of p38 and JNK.PD098059, which is a selective ERK inhibitor,significantly inhibited IL-2-induced cell proliferation.Conclusion:IL-2 can activate ERK1/2 pathway leading to proliferation of BPH-1 cells. Chapter threeEffects of Interleukin-2 on Apoptosis and Bcl-2,Bax, Caspase-3 Expression in Prostatic Epithelial CellsObjective:To investigate the effects of IL-2 on the apoptosis and the expression of apoptosis-related proteins(Bcl-2,Bax,Caspase-3) in human prostatic epithelial cell line BPH-1.Methods:Cell apoptosis was analyzed by acidine orange/ethidium bromide staining and ELISA.The expression of Bcl-2,Bax and Caspase-3 were measured using Western blot.Results:IL-2 inhibited BPH-1 cells apoptosis induced by serum deprivation in a dose- and time-dependent manner and decreased Caspase-3 activation.Under the treatment of IL-2,Western blot analysis showed an increased Bcl-2 protein and decreased Bax protein expression.Conclusion:IL-2 can protect BPH-1 cells against apoptosis by regulating Bcl-2/Bax expression,and by blocking the activation of Caspase-3. Chapter fourInterleukin-2 Inhibits Differentiation of Prostatic Stromal Cells through Regulation of Prostatic Epithelial Cells ParacrineObjective:To characterize the effects of IL-2 on differentiation in stromal cells through regulation of human prostatic epithelial cell line BPH-1 paracrine.Methods:BPH-1 cells were stimulated with different concentrations of IL-2.Conditioned medium(CM) were harvested and their effects on stromal cells were tested,mRNA of transforming growth factorβ1 (TGF-β1) was analyzed by RT-PCR.Western blot was used to determine smooth muscle myosin heavy chain(SM-MHC).ELISA was used to measure TGF-β1 protein secretion.Results:IL-2 inhibited the mRNA expression and secretion of TGF-β1 in BPH-1 cells.A neutralizing antibody to TGF-β1 inhibited the stimulation of SM-MHC in stromal cells by BPH-1CM.The expression of SM-MHC decreased when stromal cells were cultured with CM harvested from IL-2 treated BPH-1 cells.Conclusion:IL-2 inhibits differentiation of stromal cells by involving regulation of TGF-β1 expression and secretion.