Goto Akiteru, Tanaka Masamitsu, Yoshida Makoto, Umakoshi Michinobu, Nanjo Hiroshi, Shiraishi Kouya, Saito Motonobu, Kohno Takashi, Kuriyama Sei, Konno Hayato, Imai Kazuhiro, Saito Hajime, Minamiya Yoshihiro, Maeda Daichi
Department of Cellular and Organ Pathology, Graduate School of Medicine, Akita University, Akita, Japan.
Department of Molecular Medicine and Biochemistry, Graduate School of Medicine, Akita University, Akita, Japan.
PLoS One. 2017 Jul 12;12(7):e0181270. doi: 10.1371/journal.pone.0181270. eCollection 2017.
miR-451 is a tumor suppressive microRNA with several target genes, including Macrophage migration inhibitory factor (MIF). As little is known about the expression and clinicopathological significance of mir-451 in NSCLC, we performed a clinicopathological study of 370 NSCLC cases to clarify them. Cell biological experiments were also performed on NSCLC cell lines to confirm the tumor-suppressive role of miR-451 and whether or not MIF is targeted by miR-451.
We analyzed 370 NSCLC cases for the miR-451 expression by quantitative real-time polymerase chain reaction and the MIF expression by immunohistochemistry. Eighty-four background lung tissue samples were also evaluated for the miR-451 expression. The clinicopathological and genetic factors surveyed were the disease-free survival, smoking status, histological type, disease stage, EGFR gene mutations and ALK rearrangements. In 286 adenocarcinoma cases, the invasive status (adenocarcinoma in situ, minimally invasive adenocarcinoma and invasive adenocarcinoma) was also evaluated. Five NSCLC cell lines (H23, H441, H522, H1703, and H1975) were cultured and evaluated for their miR-451 and MIF expression. The cell lines with lower miR-451 and higher MIF expressions were then selected and transfected with miR-451-mimic to observe its effects on MIF expression, Akt and Erk status, cell proliferation, and cell migration.
The miR-451 expression was down-regulated in cancer tissues compared with background lung tissues (P<0.0001). Factors such as advanced disease stage, positive pleural invasion and nodal status and being a smoker were significantly correlated with a lower expression of miR-451 (P<0.05 each), while EGFR gene mutations and ALK rearrangements were not. In adenocarcinoma, invasive and minimally invasive adenocarcinoma showed lower expression of miR-451 than adenocarcinoma in situ (P<0.0005, respectively). A survival analysis showed that a lower expression of miR-451 was an independent predictor of a poor prognosis for NSCLC (P<0.05). The MIF expression was inversely correlated with the miR-451 expression. Out of 5 NSCLC cell lines examined, H441 and H1975 showed higher MIF and lower miR-451 expressions. After the transfection of miR-451-mimic, the MIF expression and phosphorylated Akt expression of these cell lines was suppressed, as were cell proliferation and cell migration.
This clinicopathological study of 370 NSCLC cases and the cell biological studies of NSCLC cell lines clarified the tumor-suppressive role of miR-451 and its prognostic value. We also validated MIF as a target of miR-451 in NSCLC.
miR - 451是一种具有多个靶基因的肿瘤抑制性微小RNA，其中包括巨噬细胞迁移抑制因子（MIF）。由于对miR - 451在非小细胞肺癌（NSCLC）中的表达及临床病理意义知之甚少，我们对370例NSCLC病例进行了临床病理研究以阐明这些问题。同时也对NSCLC细胞系进行了细胞生物学实验，以证实miR - 451的肿瘤抑制作用以及MIF是否为miR - 451的靶标。
我们通过定量实时聚合酶链反应分析了370例NSCLC病例中miR - 451的表达，并通过免疫组织化学分析了MIF的表达。还评估了84份背景肺组织样本中miR - 451的表达。所调查的临床病理和基因因素包括无病生存期、吸烟状况、组织学类型、疾病分期、表皮生长因子受体（EGFR）基因突变和间变性淋巴瘤激酶（ALK）重排。在286例腺癌病例中，还评估了浸润状态（原位腺癌、微浸润腺癌和浸润性腺癌）。培养了5种NSCLC细胞系（H23、H441、H522、H1703和H1975）并评估了它们的miR - 451和MIF表达。然后选择miR - 451表达较低且MIF表达较高的细胞系，用miR - 451模拟物进行转染，以观察其对MIF表达、Akt和Erk状态、细胞增殖及细胞迁移的影响。
与背景肺组织相比，癌组织中miR - 451的表达下调（P<0.0001）。疾病晚期、胸膜侵犯阳性和淋巴结状态以及吸烟等因素与miR - 451表达较低显著相关（各P<0.05），而EGFR基因突变和ALK重排则不然。在腺癌中，浸润性和微浸润性腺癌的miR - 451表达低于原位腺癌（分别为P<0.0005）。生存分析表明，miR - 451表达较低是NSCLC预后不良的独立预测因素（P<0.05）。MIF表达与miR - 451表达呈负相关。在所检测的5种NSCLC细胞系中，H441和H1975表现出较高的MIF表达和较低的miR - 451表达。转染miR - 451模拟物后，这些细胞系的MIF表达和磷酸化Akt表达受到抑制，细胞增殖和细胞迁移也受到抑制。
这项对370例NSCLC病例的临床病理研究以及对NSCLC细胞系的细胞生物学研究阐明了miR - 451的肿瘤抑制作用及其预后价值。我们还验证了MIF是NSCLC中miR - 451的靶标。
