背景:γ1-Adaptin是衔接蛋白复合物-1(AP-1)的一个亚基,它调节反式高尔基网络(TGN)和内体之间的细胞内运输。据报道,由于AP-1亚基的表达水平与细胞增殖和癌症恶性肿瘤有关,我们研究了乳腺癌组织中γ1-Adaptin的免疫组织化学表达与临床病理因素和无复发生存期(RFS)之间的关系。
方法:用γ1-adaptin耗竭的SK-BR-3细胞系进行细胞增殖,迁移,和入侵测定。使用针对γ1-adaptin的抗体通过免疫组织化学(IHC)检查γ1-adaptin的细胞内定位,并使用TGN和核内体的标记进行双重免疫组织荧光(IHF)显微镜检查。对199例原发性乳腺癌患者的IHC样本中的γ1-适应素强度进行了定量,并评估了其与临床病理因素和RFS的关系。
结果:细胞生长,迁移,γ1-adaptin耗竭可显着抑制SK-BR-3细胞的侵袭。尽管通过IHC在癌组织中的染色模式因病例而异,双IHF显示γ1-适应素主要定位于EEA1阳性内体,但不是在TGN。肿瘤区域的γ1-适应素强度明显高于非肿瘤区域。Ki-67(高)患者也较高,ER(-),PgR(-),HER2(+)在乳腺癌的亚型中,γ1-适应素强度在HER2中高于腔A或腔B。生存分析的结果表明,高γ1-适应素强度与较差的RFS显着相关,在ER(+)组中也观察到这种关联,PgR(+),HER2(-),Ki-67(高),或管腔B。此外,Cox比例风险模型显示,高γ1-适应素强度是独立的预后因素。
结论:这些结果表明γ1-Adaptin的内体表达与乳腺癌的恶性程度呈正相关,可能是一种新的预后指标。
BACKGROUND: γ1-Adaptin is a subunit of adaptor protein complex-1 (AP-1), which regulates intracellular transport between the trans-Golgi network (TGN) and endosomes. Since expression levels of AP-1 subunits have been reported to be associated with cell proliferation and cancer malignancy, we investigated the relationships between the immunohistochemical expression of γ1-adaptin and both clinicopathological factors and relapse-free survival (RFS) in breast cancer tissue.
METHODS: SK-BR-3 cell line depleted of γ1-adaptin was used for cell proliferation, migration, and invasion assay. Intracellular localization of γ1-adaptin was examined with immunohistochemistry (IHC) using an antibody against γ1-adaptin, and with double immunohistofluorescence (IHF) microscopy using markers for the TGN and endosome. γ1-Adaptin intensities in IHC samples from 199 primary breast cancer patients were quantified and assessed in relation to clinicopathological factors and RFS.
RESULTS: Cell growth, migration, and invasion of SK-BR-3 cells were significantly suppressed by the depletion of γ1-adaptin. Although the staining patterns in the cancer tissues varied among cases by IHC, double IHF demonstrated that γ1-adaptin was mainly localized in EEA1-positive endosomes, but not in the TGN. γ1-Adaptin intensity was significantly higher in the tumor regions than in non-tumor regions. It was also higher in patients with Ki-67 (high), ER (-), PgR (-), and HER2 (+). Among subtypes of breast cancer, γ1-adaptin intensity was higher in HER2 than in luminal A or luminal B. The results of the survival analysis indicated that high γ1-adaptin intensity was significantly associated with worse RFS, and this association was also observed in group with ER (+), PgR (+), HER2 (-), Ki-67 (high), or luminal B. In addition, the Cox proportional hazards model showed that high γ1-adaptin intensity was an independent prognostic factor.
CONCLUSIONS: These results suggest that the endosomal expression of γ1-adaptin is positively correlated with breast cancer malignancy and could be a novel prognostic marker.