PEDF肽段44-mer对前列腺癌细胞PC-3分化作用的研究

Study on the effect of PEDF peptide 44-mer on differentiation of prostate cancer cell line PC-3

目的观察色素上皮细胞衍生因子(PEDF)肽段44-mer(57-101)诱导激素非依赖性前列腺癌(PCa)细胞PC-3发生神经内分泌分化(NED),并探讨其对前列腺癌的治疗机理。方法体外合成44-mer并对PC-3的生长进行干预,以采用不同浓度44-mer诱导作为实验组,未用44-mer诱导作为对照组。从形态、标志物两方面证实部分细胞发生NED;采用水溶性四氮唑(WST-1)、流式细胞仪检测诱导后细胞的增殖情况及细胞周期。建立荷瘤裸鼠模型,实验组腹腔注射44-mer,定期测量肿瘤体积,并对标本进行免疫组化染色以检测嗜铬粒素A(ChrA)的表达情况;对照组腹腔注射磷酸盐缓冲液(PBS),并定期测量肿瘤体积。结果实验组PC-3中发生NED形态学改变的细胞所占的比率为18.65%±1.26%,明显高于对照组(3.62%±0.44%)(P<0.01);1、10、100 nmol/L44-mer分别诱导PC-3 3 d后培养液中的ChrA水平分别为(168.97±5.36)、(263.95±5.30)、(325.24±5.74)ng/mL,均高于对照组[(115.97±2.16)ng/mL](P均<0.01);免疫印迹法显示实验组PC-3神经特异性烯醇化酶(NSE)、ChrA的表达升高;实验组G0/G1期的细胞占79.24%±3.24%,明显高于对照组(65.18%±4.53%)(P<0.05);1、10、100 nmol/L44-mer诱导PC-3 6 d后WST-1实验的吸光度值分别为2.05±0.07、1.98±0.06、1.78±0.09,均低于对照组(2.54±0.08,P均<0.01)。与对照组肿瘤体积[(574.70±63.78)mm3]相比,实验组的肿瘤体积明显减小[(222.21±49.51)mm3](P<0.01),且标本中ChrA表达上升。结论 44-mer诱导PC-3发生NED,并抑制其在体内外的增殖。

Objective To observe the neuroendocrine differentiation（NED） effect of pigment epithelium-derived factor（PEDF） peptide 44-mer（57-101） on the androgen independent prostate cancer（PCa） cell line PC-3 and investigate the therapeutic mechanism of this peptide for PCa.Methods PC-3 were treated with 44-mer which were synthesized in vitro.The subjects induced by different concentrations of 44-mer were perfromed as experiment group,and they treated without 44-mer were performed as controls.NED was confirmed by morphological observation and specific markers expression.The proliferation and cell cycle of treated cells were examined with water-soluble tetrazolium（WST-1） assay and flow cytometry.The xenograft model of PCa in nude mice was established.After the 44-mer was administrated by intraperitoneal injection,the tumors were measured and excised to perform immunohistochemistry for chromogranin A（ChrA） in the experiment group.In the controls,phosphate buffer saline（PBS） was administrated by intraperitoneal injection,and the volume of trumors was measured regularly.Results The percentage of PC-3 experienced morphological changes toward a neuroendocrine phenotype increased to 18.65%±1.26% in experimental group（controls： 3.62%±0.44%,P0.01）.The concentrations of ChrA in conditioned medium after treatment with 1,10 and 100 nmol/L 44-mer were（168.97±5.36）,（263.95±5.30） and（325.24±5.74） ng/mL,respectively,which were higher than those of controls [（115.97±2.16） ng/mL]（P0.01）.Western blot showed the higher expression of neuron-specific enolase（NSE） and ChrA in cells treated with 44-mer.The percentage of cells at G0/G1 stage in experimental group was 79.24%±3.24%,which was higher than that in controls 65.18%±4.53%（P0.05）.After PC-3 were treated with 1,10 and 100 nmol/L 44-mer for 6 d,WST-1 assay showed the absorbance values were 2.05±0.07,1.98±0.06 and 1.78±0.09,respectively,while that of controls was 2.54±0.08（P0.01）.Compared to controls[（574.70±63.78） mm3],the tumor volumes in experimental group were smaller [（222.21±49.51） mm3]（P0.05）with higher expression of ChrA.Conclusions 44-mer can induce the NED of PC-3 and inhibit its growth in vitro and in vivo.