Han Xu, Saiyin Hexige, Zhao Junjie, Fang Yuan, Rong Yefei, Shi Chenye, Lou Wenhui, Kuang Tiantao
Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.
The State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China.
Oncotarget. 2017 Jul 10;8(37):62195-62207. doi: 10.18632/oncotarget.19150. eCollection 2017 Sep 22.
Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive and malignant neoplasm. The aberrant expression of miR-135b-5p and secreted frizzled-related protein 4 (SFRP4) has been revealed to be involved in various cancers. However, the clinical significance of miR-135b-5p and that of its potential target SFRP4 in PDAC remain to be elucidated. Here, we found that miR-135b-5p was markedly upregulated in pancreatic cancer tissue compared with corresponding adjacent normal tissue, whereas SFRP4 was significantly downregulated. The expression of miR-135b-5p was negatively correlated with the expression of SFRP4. PDAC patients with regional lymph node metastases, vascular invasion, tumor microthrombus and higher PET-CT SUVmax values had significantly higher expression of miR-135b-5p. Immunoblotting revealed that regional lymph node metastases were correlated with expressive states of SFRP4. Negative SFRP4 expression was significantly associated with old age, larger tumor size, regional lymph node metastasis and poor differentiation. Survival analyses demonstrated that miR-135b-5p and SFRP4 could predict outcomes and that miR-135b-5p was an independent predictor. , the overexpression of miR-135b-5p promoted the migration and proliferation of PANC-1 and MiaPaCa-2 cells, while immunoblotting demonstrated the downregulation of SFRP4 and the upregulation of beta-catenin. Inhibition of miR-135b-5p suppressed migration, induced apoptosis of PANC-1 and AsPC-1 cells, and reduced the expression of beta-catenin. A luciferase reporter assay confirmed that miR-135b-5p repressed the expression of SFRP4 via the direct targeting of its 3'-untranslated regions. In conclusion, the overexpression of miR-135b-5p and the downregulation of SFRP4 were associated with unfavorable clinical characteristics and poor prognosis, and SFRP4 was shown to be a direct downstream target of miR-135b-5p. Thus, the mechanism that underlies the miR-135b-5p-SFRP4-Wnt/beta-catenin axis represents a potential target for PDAC diagnosis and therapy.
胰腺导管腺癌（PDAC）是一种侵袭性很强的恶性肿瘤。已发现miR-135b-5p和分泌型卷曲相关蛋白4（SFRP4）的异常表达与多种癌症有关。然而，miR-135b-5p及其潜在靶标SFRP4在PDAC中的临床意义仍有待阐明。在此，我们发现与相应的癌旁正常组织相比，胰腺癌组织中miR-135b-5p明显上调，而SFRP4明显下调。miR-135b-5p的表达与SFRP4的表达呈负相关。有区域淋巴结转移、血管侵犯、肿瘤微血栓形成以及PET-CT SUVmax值较高的PDAC患者，其miR-135b-5p表达明显更高。免疫印迹显示区域淋巴结转移与SFRP4的表达状态相关。SFRP4阴性表达与老年、肿瘤体积较大、区域淋巴结转移及低分化显著相关。生存分析表明，miR-135b-5p和SFRP4可预测预后，且miR-135b-5p是一个独立的预测指标。此外，miR-135b-5p的过表达促进了PANC-1和MiaPaCa-2细胞的迁移和增殖，而免疫印迹显示SFRP4下调且β-连环蛋白上调。抑制miR-135b-5p可抑制PANC-1和AsPC-1细胞的迁移、诱导其凋亡，并降低β-连环蛋白的表达。荧光素酶报告基因检测证实，miR-135b-5p通过直接靶向SFRP4的3'-非翻译区来抑制其表达。总之，miR-135b-5p的过表达和SFRP4的下调与不良临床特征及预后不良相关，且SFRP4被证明是miR-135b-5p的直接下游靶标。因此，miR-135b-5p-SFRP4-Wnt/β-连环蛋白轴的潜在机制是PDAC诊断和治疗的一个潜在靶点。
