Prostate cancer occurs through multiple steps until advanced metastasis. Signaling pathways studies can result in the identification of targets to interrupt cancer progression. Glypicans are cell surface proteoglycans linked to the membrane through glycosylphosphatidylinositol. Their interaction with specific ligands has been reported to trigger diverse signaling, including Wnt. In this study, prostate cancer cell lines PC-3, DU-145, and LNCaP were compared to normal prostate RWPE-1 cell line to investigate glypican family members and the activation of the Wnt signaling pathway. Glypican-1 (GPC1) was highly expressed in all the examined cell lines, except for LNCaP, which expressed glypican-5 (GPC5). The subcellular localization of GPC1 was detected on the cell surface of RWPE-1, PC-3, and DU-145 cell lines, while GPC5 suggested cytoplasm localization in LNCaP cells. Besides glypican, flow cytometry analysis in these prostate cell lines confirmed the expression of Wnt-3a and unphosphorylated β-catenin. The co-immunoprecipitation assay revealed increased levels of binding between Wnt-3a and glypicans in cancer cells, suggesting a relationship between these proteoglycans in this pathway. A marked increase in nuclear β-catenin was observed in tumor cells. However, only PC-3 cells demonstrated activation of canonical Wnt signaling, according to the TOPFLASH assay. GPC1 was the majorly expressed gene in all the studied cell lines, except for LNCaP, which expressed GPC5. We assessed by co-immunoprecipitation that these GPCs could interact with Wnt-3a. However, even though nuclear β-catenin was found increased in the prostate cancer cells (i.e., PC-3, DU-145 and LNCaP), activation of Wnt pathway was only found in PC-3 cells. In these PC-3 cells, GPC1 and Wnt-3a revealed high levels of colocalization, as assessed by confocal microscopy studies. This suggests a localization at the cellular surface, where Frizzled receptor is required for downstream activation. The interaction of Wnt-3a with GPCs in DU-145 and LNCaP cells, which occurs in absence of Wnt signaling activation, requires further studies. Once non-TCF-LEF proteins can also bind β-catenin, another signaling pathway may be involved in these cells with regulatory function.

中文翻译：

---

Glypican 蛋白聚糖显示出与人前列腺癌细胞中 Wnt-3a 的内在相互作用，这些相互作用并不总是与级联激活相关

前列腺癌通过多个步骤发生，直到晚期转移。信号转导通路研究可以识别出阻断癌症进展的靶标。Glypicans 是通过糖基磷脂酰肌醇与膜连接的细胞表面蛋白聚糖。据报道，它们与特定配体的相互作用会触发多种信号传导，包括 Wnt。在本研究中，将前列腺癌细胞系 PC-3、DU-145 和 LNCaP 与正常前列腺 RWPE-1 细胞系进行比较，以研究磷脂酰肌醇蛋白聚糖家族成员和 Wnt 信号通路的激活。Glypican-1 (GPC1) 在所有检查的细胞系中均高度表达，但 LNCaP 除外，其表达 glypican-5 (GPC5)。在 RWPE-1、PC-3 和 DU-145 细胞系的细胞表面检测到 GPC1 的亚细胞定位，而 GPC5 表明 LNCaP 细胞中的细胞质定位。除了磷脂酰肌醇蛋白聚糖，这些前列腺细胞系中的流式细胞术分析证实了 Wnt-3a 和未磷酸化的 β-连环蛋白的表达。免疫共沉淀试验揭示了癌细胞中 Wnt-3a 和磷脂酰肌醇蛋白聚糖之间的结合水平增加，表明这些蛋白聚糖在该途径中存在关联。在肿瘤细胞中观察到核β-连环蛋白显着增加。然而，根据 TOPFLASH 分析，只有 PC-3 细胞表现出经典 Wnt 信号的激活。GPC1 是所有研究细胞系中主要表达的基因，除了表达 GPC5 的 LNCaP。我们通过免疫共沉淀评估这些 GPC 可以与 Wnt-3a 相互作用。然而，即使发现前列腺癌细胞（即 PC-3、DU-145 和 LNCaP)，Wnt 通路的激活仅在 PC-3 细胞中发现。通过共聚焦显微镜研究评估，在这些 PC-3 细胞中，GPC1 和 Wnt-3a 显示出高水平的共定位。这表明在细胞表面定位，其中下游激活需要卷曲受体。Wnt-3a 与 DU-145 和 LNCaP 细胞中 GPC 的相互作用，发生在没有 Wnt 信号激活的情况下，需要进一步研究。一旦非 TCF-LEF 蛋白也可以结合 β-catenin，这些细胞中可能会涉及另一种具有调节功能的信号通路。其中下游激活需要卷曲受体。Wnt-3a 与 DU-145 和 LNCaP 细胞中 GPC 的相互作用，发生在没有 Wnt 信号激活的情况下，需要进一步研究。一旦非 TCF-LEF 蛋白也可以结合 β-catenin，这些细胞中可能会涉及另一种具有调节功能的信号通路。其中下游激活需要卷曲受体。Wnt-3a 与 DU-145 和 LNCaP 细胞中 GPC 的相互作用，发生在没有 Wnt 信号激活的情况下，需要进一步研究。一旦非 TCF-LEF 蛋白也可以结合 β-catenin，这些细胞中可能会涉及另一种具有调节功能的信号通路。