Department of Molecular Medicine and Medical Biotechnologies & Institute of Endocrinology and Molecular Oncology of CNR, University "Federico II", Naples, Italy.
J Cell Physiol. 2014 Oct;229(10):1417-26. doi: 10.1002/jcp.24578.
Recent studies have indicated that endoplasmic reticulum stress, the unfolded protein response activation and altered GRP78 expression can play an important role in a variety of tumors development and progression. Very recently we reported for the first time that GRP78 is increased in endometrial tumors. However, whether GRP78 could play a role in the growth and/or invasiveness of endometrial cancer cells is still unknown. Here we report that the silencing of GRP78 expression affects both cell growth and invasiveness of Ishikawa and AN3CA cells, analyzed by the (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) and transwell migration assay, respectively. At variance with Ishikawa cells, AN3CA cells showed, besides an endoplasmic reticulum, also a plasma membrane GRP78 localization, evidenced by both immunofluorescence and cell membrane biotinylation experiments. Intriguingly, flow cytometry experiments showed that the treatment with a specific antibody targeting GRP78 C-terminal domain caused apoptosis in AN3CA but not in Ishikawa cells. Induction of apoptosis in AN3CA cells was not mediated by the p53 pathway activation but was rather associated to reduced AKT phosphorylation. Interestingly, immunofluorescence analysis evidenced that endometrioid adenocarcinoma tissues displayed, similarly to AN3CA cells, also a GRP78 plasma membrane localization. These data suggest that GRP78 and its plasma membrane localization, might play a role in endometrial cancer development and progression and might constitute a novel target for the treatment of endometrial cancer.
最近的研究表明，内质网应激、未折叠蛋白反应的激活和 GRP78 表达的改变在多种肿瘤的发生和发展中可能发挥重要作用。最近我们首次报道 GRP78 在子宫内膜肿瘤中增加。然而，GRP78 是否能在子宫内膜癌细胞的生长和/或侵袭中发挥作用仍不清楚。在这里，我们报道 GRP78 表达的沉默会影响 Ishikawa 和 AN3CA 细胞的生长和侵袭性，这是通过（3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四唑溴盐）和 Transwell 迁移分析分别分析的。与 Ishikawa 细胞不同，AN3CA 细胞除了内质网外，还显示出细胞膜 GRP78 定位，这一点通过免疫荧光和细胞膜生物素化实验都得到了证明。有趣的是，流式细胞术实验表明，用针对 GRP78 C 端结构域的特异性抗体处理会导致 AN3CA 细胞凋亡，但不会导致 Ishikawa 细胞凋亡。AN3CA 细胞中诱导的凋亡不是通过 p53 通路的激活介导的，而是与 AKT 磷酸化的减少有关。有趣的是，免疫荧光分析表明，子宫内膜样腺癌组织与 AN3CA 细胞类似，也显示出 GRP78 的细胞膜定位。这些数据表明，GRP78 及其细胞膜定位可能在子宫内膜癌的发生和发展中发挥作用，并可能成为子宫内膜癌治疗的新靶点。
