间质表皮转化因子通过PI3K/AKT/MMPs信号通路促进肺腺癌细胞的侵袭转移

间质表皮转化因子（mesenchymal to epithelial transition factor，MET）在多种癌症中异常表达，影响肿瘤的发生发展，但MET影响肺腺癌的分子机制并不明确。本研究收集3例淋巴结转移的肺腺癌组织（lung adenocarcinoma tissues，LAD）和3例无淋巴结转移的肺腺癌组织，用于微阵列基因芯片分析。结果显示，与无淋巴结转移的肺腺癌组织相比，有淋巴结转移的肺腺癌组织中有1 314条mRNAs表达上调，400条mRNAs表达下调。其中，MET在有淋巴结转移的肺腺癌组织中表达显著升高。随机选取8个差异表达基因，对收集的潍坊医学院附属医院2014年2月至2017年2月间有淋巴结转移的肺腺癌组织和无淋巴结转移的肺腺癌组织各30例通过qRT -PCR实验进行微阵列基因芯片验证。结果显示，所选mRNAs的表达与微阵列结果一致，验证了微阵列基因芯片结果的准确性。通过Western 印迹进一步检测MET的表达。结果显示，相较于正常肺上皮细胞，肺腺癌细胞中MET的表达显著升高。利用质粒转染，敲减肺腺癌细胞A549中的MET，Transwell侵袭实验结果显示，敲减MET后肺腺癌细胞的侵袭能力明显降低；对各细胞组进行EGF（epidermal growth factor）处理并检测PI3K/AKT/MMPs信号通路，Western 印迹检测结果显示，敲减MET后，肺腺癌细胞中基质金属蛋白酶-2（matrix metalloproteinase 2，MMP-2）和MMP-9的表达显著下降， AKT的磷酸化水平也显著下降。上述结果表明，MET可通过激活PI3K/AKT信号通路进而增加MMPs的表达促进肺腺癌的侵袭转移。

MET Promotes Invasion and Metastasis of Lung Adenocarcinoma Cells through PI3K/AKT/MMPs Signaling Pathway

Mesenchymal to epithelial transition factor (MET) is abnormally expressed in many cancers, but the molecular mechanism of MET affecting lung adenocarcinoma is not clear. In this study, 3 cases of lung adenocarcinoma tissues (LAD) with lymph node metastasis and 3 cases of LAD without lymph node metastasis were collected for microarray gene chip analysis. The results showed that 1 314 mRNAs were up regulated and 400 mRNAs were down regulated in LADs with lymph node metastasis, and the expression of MET was significantly increased in lung adenocarcinoma tissues with lymph node metastasis, compared with those without lymph node metastasis. Eight differentially expressed genes were randomly selected, and qRT-PCR was used to verify the results of microarray gene chip in 30 cases of LADs with lymph node metastasis collected from February 2014 to February 2017 in Affiliated Hospital of Weifang Medical University. The results showed that the expression of the selected mRNAs was consistent with the microarray data, which verified the accuracy of the microarray gene chip results. The expression of MET was further detected by Western blot, and the results showed that the expression of MET in lung adenocarcinoma cells was significantly higher than that in normal lung epithelial cells. Transwell invasion experiment results showed that the invasion ability of A549 lung epithelial cells was significantly reduced after knockdown of MET. After treated with EGF (epidermal growth factor), results showed that the expression levels of matrix metalloproteinase 2 (MMP-2) and MMP-9 in lung adenocarcinoma cells were significantly decreased after the knockout of MET, and the phosphorylation level of AKT was also significantly decreased. These results indicated that MET can promote the invasion and metastasis of lung adenocarcinoma cells by activating the PI3K/AKT signaling pathway and thereby increasing the expression of MMPs.