Downregulation of protein disulfide-isomerase A3 expression inhibits cell proliferation and induces apoptosis through STAT3 signaling in hepatocellular carcinoma
Downregulation of protein disulfide-isomerase A3 expression inhibits cell proliferation and induces apoptosis through STAT3 signaling in hepatocellular carcinoma
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DOI：
10.3892/ijo.2019.4710
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发表时间：
2019-04-01
影响因子：
5.2
通讯作者：
Naito, Zenya
中科院分区：
文献类型：
--
作者：
Kondo, Ryota;Ishino, Kousuke;Naito, Zenya
蛋白质二硫键异构酶A3（PDIA 3）是一种分子伴侣蛋白，可调节新合成的糖蛋白的折叠并响应内质网（ER）应激。既往研究报道PDIA 3在肝细胞癌（HCC）中的表达增加是预后不良的标志。然而，人们对这一机制仍然知之甚少。因此，本研究的目的是了解PDIA 3在HCC发展中的作用。首先，53例HCC组织的免疫组化染色显示，PDIA 3高表达的HCC组织比低表达的HCC组织表现出更高的增殖指数和更少的凋亡细胞。此外，PDIA 3的敲低显著抑制HCC细胞系中的细胞增殖并诱导细胞凋亡。这些结果表明PDIA 3调节HCC中的细胞增殖和凋亡。PDIA 3敲低是否通过ER应激诱导细胞凋亡的检查显示，PDIA 3敲低并不增加HCC细胞系中的ER应激标记物78 kDa葡萄糖调节蛋白。此外，PDIA 3和信号转导和转录激活因子3（STAT 3）信号通路之间的关联进行了研究，在体外和体内。免疫荧光染色和免疫共沉淀实验分别揭示了PDIA 3和STAT 3在HCC细胞系中的共定位和结合。PDIA 3的敲低降低了磷酸化STAT 3（P-STAT 3; Tyr 705）和STAT 3信号通路的下游蛋白质的水平：抗凋亡蛋白质（Bcl-2样蛋白1、诱导的髓性白血病细胞分化蛋白Mcl-1、存活素和X连锁凋亡抑制蛋白）。此外，PDIA 3敲低对用酪氨酸蛋白激酶JAK/STAT 3信号传导抑制剂AG 490处理的HCC细胞系中的细胞增殖几乎没有抑制作用。最后，在35个HCC样本的免疫染色后，PDIA 3和P-STAT 3表达之间的关联被证明。总之，目前的数据表明PDIA 3通过STAT 3信号通路促进HCC进展。
Protein disulfide-isomerase A3 (PDIA3) is a chaperone protein that modulates folding of newly synthesized glycoproteins and responds to endoplasmic reticulum (ER) stress. Previous studies reported that increased expression of PDIA3 in hepatocellular carcinoma (HCC) is a marker for poor prognosis. However, the mechanism remains poorly understood. The aim of the present study, therefore, was to understand the role of PDIA3 in HCC development. First, immunohistochemical staining of tissues from 53 HCC cases revealed that HCC tissues with high PDIA3 expression exhibited a higher proliferation index and contained fewer apoptotic cells than those with low expression. In addition, the knockdown of PDIA3 significantly inhibited cell proliferation and induced apoptosis in HCC cell lines. These results suggest that PDIA3 regulates cell proliferation and apoptosis in HCC. An examination of whether PDIA3 knockdown induced apoptosis through ER stress revealed that PDIA3 knockdown did not increase ER stress marker, 78 kDa glucose-regulated protein, in HCC cell lines. Furthermore, the association between PDIA3 and the signal transducer and activator of transcription 3 (STAT3) signaling pathway were investigated in vitro and in vivo. Immunofluorescence staining and co-immunoprecipitation experiments revealed colocalization and binding, respectively, of PDIA3 and STAT3 in HCC cell lines. The knockdown of PDIA3 decreased the levels of phosphorylated STAT3 (P-STAT3; Tyr705) and downstream proteins of the STAT3 signaling pathway: The anti-apoptotic proteins (Bcl-2-like protein 1, induced myeloid leukemia cell differentiation protein Mcl-1, survivin and X-linked inhibitor of apoptosis protein). In addition, PDIA3 knockdown provided little inhibitory effect on cell proliferation in HCC cell lines treated with AG490, a tyrosine-protein kinase JAK/STAT3 signaling inhibitor. Finally, an association was demonstrated between PDIA3 and P-STAT3 expression following immunostaining of 35 HCC samples. Together, the present data suggest that PDIA3 promotes HCC progression through the STAT3 signaling pathway.